We have authorized service centers worldwide providing in-country support. Our service centers can assist you with technical support and equipment repairs.
Comtech EF Data Corp. (Headquarters)
Tempe, AZ 85281 USA
Tel: +1.480.333.2200
Fax: +1.480.333.2540
- Medical insurance – choice of HMO / POS / HSA
- Dental insurance – choice of HMO / PPO
- Vision insurance
- Company paid life and Accidental Death and Dismemberment (AD&D) insurance
- Optional supplemental life and AD&D insurance
- Disability insurance – company paid short-term
- Optional supplemental short-term and long-term disability insurance
- Athletic club reimbursement
- 401(k) company match and automatic enrollment for all employees
- Employee stock purchase plan
- Tuition assistance
- Flexible spending account plan
- Paid vacation
- Paid personal time off
- 10 company paid holidays per year
- Sick leave
- Family leave
- Miscellaneous leave policies (military, jury duty, bereavement)
Traffic Prioritization shapes bandwidth utilization so that capacity requirements for mission-critical applications are always met. By controlling the transmission of specific applications, administrators are able to keep within bandwidth limits and to prioritize applications over satellite links.
Quality of Service (QoS) is used to classify and prioritize network applications based on business objectives to guarantee optimal application performance regardless of network conditions by assigning priority or bandwidth guarantees and limits for each application. Satellite links are subjected to limited amount of bandwidth. QoS traffic management enables network administrators to define preferential treatment for certain classes of traffic. For hub deployments, QoS provides TCP rate controls and priority levels capable of to supporting many remote sites, while, remote sites use QoS to prioritize applications and user types.
Even with proper QoS priorities in place, applications with large file transfers, such as CIFS, FTP, and backup systems can starve real-time applications such as VoIP and streaming media (e.g. video). Even if a real-time application has priority, the bulky nature of large-transfers takes too long to clear the satellite link – even when queuing and traffic shaping are enabled. The added latency that results can make a critical application such as VoIP impossible for many remote sites. To address this problem, Stampede’s FX Series reduces the size of data packets, and intelligently manages packets based on satellite link capability and application profiles.
The FX Series Traffic Shaping is a powerful feature which ensures on-time delivery of time-critical information. Through specific port assignments, priorities and policies that can be assigned at the database-level, guaranteeing Quality of Service for critical applications. The FX Series Traffic shaping feature allows different TCP ports to be assigned to individual applications, such as email and VoIP. These TCP ports are used in conjunction with Traffic Shaping hardware to provide different levels of service quality. This allows administrators to define the “Quality of Service” attributes used for traffic control based on either “Traffic Classes” or “Bandwidth Pools”.
Dynamic Data Suppression (DDS) is block level de-duplication, which is a technique for recognizing and replacing repetitive streams of payload data with signatures prior to transmission over the satellite links. DDS is not application protocol specific and can be applied to most TCP application traffic. The FX Series intelligently monitors the data stream and is able to distinguish protocol headers which change frequently from payload data which is often static. The FX Series extracts this payload data and segments it into blocks, storing each block into persistent memory known as a “byte cache”. Blocks of data are replaced with a signature for that data. This generates significant data reduction.
The FX Series provides application-aware modules for HTTP, HTTP/S, CIFS, MAPI, POP3, SMTP, and FTP that dramatically reduce costly handshakes and intelligently apply compression to lower bandwidth consumption and reduce latency.
Stampede specializes in optimizing protocols by consolidating multiple transactions into a single transaction, which eliminates round-trips, performing cache differencing on dynamically generated content, and bi-directional data compression. In addition, our patented technology (TurboStreaming) enables the transfer of previously compressed objects up to 5 times faster through intelligent multiplexing across multiple TCP sessions.
- TCP and HTTP applications have chatty protocols that put added delay in satellite networks, as do delay-sensitive applications such as VoIP and applications such as Microsoft Exchange and CIFS.
- IT managers are placing thousands of applications on their satellite links. Many of these applications are mission-critical, and compete over a limited amount of bandwidth.
Advanced Virtual Pipelining™ (AVP) is a technique developed by Stampede that provides 40% performance improvements for browser-based applications. This performance improvement is on top of the FX Series industry leading performance, and is only possible because of innovative technology for two-way application acceleration.It becomes an important and standard acceleration technique used with the FX Series family of products.
AVP is a highly optimized implementation of the patented TurboStreaming™ (multiplexed TCP sessions, patent # 7,543,072) that enables HTTP browser traffic to be intermixed across multiple “pipelines”. All browser activity is optimized, including the network-intensive polling associated with Web 2.0 and AJAX applications. A key advantage of our AVP implementation is that communication resources can be shared across multiple applications, and all HTTP requests and responses from any application (including multiple browsers) are intermixed simultaneously across multiple concurrent sessions. AVP serves as a platform for the consolidation and aggregation of all Web-based traffic from a given user. AVP logically aggregates multiple HTTP protocol streams across a few TCP sessions. Individual objects or pieces of objects can be split into any size and then multiplexed with other object data and reconstructed as needed SNSPs that deliver mixed payloads consisting of business-critical applications and data, streaming media, Voice Over Internet Protocol (VoIP) and other network-intensive traffic. The end result is improved throughput and faster response time for the end-user.
AVP enables the browser to open multiple pipelines (10s or even 100s) that communicate with the FX Series remote appliances. All of this data, from all browsers and all browser windows, is intelligently multiplexed over multiple TCP sessions (TurboStreaming) back to the head-end FX Series appliance. This fully utilizes all available bandwidth, and enables the browser to function at its full potential. This is only possible because of our advanced, industry leading two-sided acceleration technology.
The FX Series uses patented (PN# 6,012,085) “Multi-get” technology to reduce the chattiness of the HTTP protocol. In some cases, a single page retrieval will cause hundreds of HTTP Get requests to be issued by the browser.
A single page is returned to the browser that contains many embedded URLs needed for proper display of the original page. These URLs can be for additional HTML pages, image data such as pictures in the form of gifs and jpegs, java scripts and so on. The browser will first download the main page and then request the embedded URLs essentially one at a time. The latest browsers typically open several connections to retrieve these objects to overlap the retrieval process.
There are two problems with this approach. First, each item request causes a separate HTTP request/response round trip. For a first time retrieval of a page this may mean between 10 and 100 or more round trips to the Web server. More complicated pages can cause significantly more round trips. Secondly, the extra connections the browser uses can add significant load to a Web server and to the network infrastructure.
The FX Series Multi-get technology examines the first page when it is downloaded and builds a patented Multi-get request that contains an optimized “GET” for all of the necessary additional objects. The FX Series appliance parses this request and streams the objects to the remote FX Series appliance that caches them and returns them to the browser when the browser requests them. The FX Series Multi-get/Multi-verify technology determines which objects need to be retrieved freshly and which can be conditionally retrieved. All objects are retrieved in one logical request and streamed to the FX Series appliance.
The Multi-get/Multi-verify technology virtually eliminates the “chattiness” of the HTTP protocol. However, the Multi-get technology is not limited to HTML pages and is employed wherever possible; such as with JAVA Server Pages (JSPs) and Active Server Pages (ASPs) that have embedded Java Scripts. Advanced protocol optimizations drive significant improvements in bandwidth efficiencies and time savings, providing significant payload reductions and improved application delivery speeds. The FX Series specializes in optimizing the HTTP protocol by consolidating multiple transactions into a single transaction, which eliminates round-trips that add latency that can be responsible for up to 95% of the total application delay. Important protocols for satellite communications are HTTP (web mail, web surfing, enterprise web apps), POP3/ SMTP (email), HTTPS (enterprise accounts), CIFS (enterprise accounts). Stampede delivers true HTTP / HTTPS protocol optimization:
- Multi-get
- Content validation
- Intelligent cache-differencing, including dynamic content
- JPEG compression and smoothing
Intelligently caches Microsoft® Updates on the client side saving significant bandwidth attributed to “Patch Tuesday”. The FX Series caching methodology handles the rather complicated procedures employed by Microsoft and other AV vendors to request updates by requesting “partial objects”. This reduces the amount of data sent over satellite links to reduce bandwidth consumption and provide faster response times for end-users.
The FX Series Remote can dramatically curb bandwidth consumption by caching software updates published frequently by Microsoft, Symantic, Adobe, Apple and many other leading software vendors. Most Satellite service providers are aware of the bandwidth impact of “Patch Tuesday” – the day that Windows updates are distributed. The delivery of these updates is performed when software that resides on client devices downloads the new content in the background by requesting “partial content” over HTTP. The complex nature of “partial-content” HTTP requests thwarts the capabilities of most caching devices, however the FX Series Remote appliance caching engine can handle these requests. Once the content is cached by the FX Series Remote, subsequent retrievals by the updating agents that request “partial-content” will be satisfied by the FX Series Remote appliance, eliminating the need to repetitively transfer the same updates over satellite links.
The FX Series multiplexes large data objects using Stampede’s patented TurboStreaming™ (multiplexed TCP sessions, patent # 7,543,072) that enables HTTP browser traffic to be intermixed across multiple “pipelines”. All browser activity is optimized, including the network-intensive polling associated with Web 2.0 and AJAX applications. A key advantage of TurboStreaming is that communication resources can be shared across multiple applications, and all HTTP requests and responses from any application (including multiple browsers) are intermixed simultaneously across multiple concurrent sessions.
TurboStreaming serves as a platform for the consolidation and aggregation of all Web-based traffic from a given user. Multiple HTTP protocol streams are logically aggregated across a few TCP sessions. Individual objects or pieces of objects can be split into any size and then multiplexed with other object data and reconstructed as needed SNSPs that deliver mixed payloads consisting of business-critical applications and data, streaming media, Voice Over Internet Protocol (VoIP) and other network-intensive traffic. The end result is improved throughput and faster response time for the end-user.
TurboStreaming enables the browser to open multiple pipelines (10s or even 100s) that communicate with the FX Series remote appliances. All of this data, from all browsers and all browser windows, is intelligently multiplexed over multiple TCP sessions back to the head-end FX Series appliance. This fully utilizes all available bandwidth, and enables the browser to function at its full potential. This is only possible because of advanced, industry leading two-sided acceleration technology.
Caching brings information closer to the end-user by storing recently accessed data in local memory or on hard disk, reducing the time it takes to bring back needed information, making the user experience more positive and action oriented. While today’s browsers maintain their own cache, they tend to be overly conservative. This means they will err on the side of requesting a new piece of data or object, usually when it really hasn’t been changed. This not only impacts response time to the end-user, but also saturates bandwidth with unnecessary data transmission. Cache Differencing takes the concept one step further and maintains identical copies of the browser’s cache at the local device and on the FX Series appliance. The FX Series then uses intelligent differencing technology to understand what data has actually changed, and then transfers only the changed data. The local device functions normally, but with less data being transferred, you realize improved utilization of the satellite network, and increased end-user productivity.
Traditionally, pages can be marked as cacheable and will have expiration dates. When they expire they must be retrieved from the original server, resulting in additional traffic and data being transmitted across the satellite network. Within a two-sided environment, the FX Series remote appliance caches all pages returned to the browser (even pages that are marked as non-cacheable) and performs validation when needed to ensure that no stale data is returned to the browser. When the browser asks for a page or an item that has expired or been marked as non-cacheable, the FX Series remote appliance sends a validation request to the FX Series appliance at the head-end. If the FX Series appliance is aware of the last page the client cache contains and can compute differences in the page, it sends just the differences to an expired page or non-cached page. If the differences are too big, or if the FX Series appliance no longer has retained the last version that the client has, then the entire page is returned and subsequently cached for future possible differencing. The client in turn reconstructs the requested page, caches it, and returns it to the browser. Checksums are calculated by the FX Series appliance at the head-end and verified at the FX Series remote appliance so that pages will never be delivered incorrectly. While this technique adds value on expired pages, it is extremely effective for dynamic page generation.
An important aspect of Stampede’s Cache Differencing is the ability to perform differencing not only on HTML GET requests but also on POST requests. This is significant because a) responses to posts are always marked non-cacheable, and b) most applications that are based on SOAP and XML (including most AJAX applications) issue SOAP requests via the HTML POST command.
Advanced protocol optimizations drive significant improvements in bandwidth efficiencies and time savings (reducing payload and latency). WAN optimization and application acceleration technologies are deployed to improve satellite network performance and increase the amount of applications and users that can be delivered over the satellite link. The FX Series manages all TCP sessions, and handles the establishing and tearing down of TCP connections locally (at LAN speeds) to avoid satellite network congestion problems. This helps to increase link utilization and improve the user experience. TCP termination offloads the responsibility from servers having to handle the overhead imposed by the volume of TCP connections from web applications.
Additionally, application level multiplexed TCP streams take advantage of all other TCP or protocol optimization done at the link level, and application-level handshakes are eliminated by consolidating transaction requests.
Benefits include:
- Increases server capacity
- Reduces the amount of traffic sent over satellite links
- Keeps the satellite links maximized for optimum utilization
- Dramatically reduces transaction TCP turns (requests and responses) that bottleneck satellite links
For customers who use Microsoft’s Internet Explorer browser, the FX Series can reduce round trips during Internet sessions by marking the HTTP objects to allow IE to extend the time that the objects are stored within the browser cache without the content becoming stale.
Caching brings information closer to the end-user by storing recently accessed data in local memory or on hard disk, reducing the time it takes to bring back needed information, making the user experience more positive and action oriented. While today’s browsers maintain their own cache, they tend to be overly conservative. This means they will error on the side of requesting a new piece of data or object, usually when it really hasn’t been changed. This not only impacts response time to the end-user, but also saturates bandwidth with unnecessary data transmissions.
The FX Series uses caching to maintain copies of routinely accessed data to eliminate unnecessary requests to Web and application servers, and from going over limited satellite links. By keeping local copies of frequently requested content, the FX Series allows organizations to significantly reduce their upstream bandwidth usage and cost, while improving performance. The FX Series acts as an intermediary from end-users requesting content (such as a file, web page, or other resource) from servers. Some of the key benefits include:
- Reducing bandwidth consumption
- Keeping servers behind the FX Series anonymous for security purposes
- Delivering fast access to content
Image Reduction and Smoothing reduces the amount of data required to represent an image without significantly altering the visual perception of the image. This is accomplished in two ways. Smoothing reduces the high frequency components or the sharpness of an image. A moderate amount of smoothing can significantly reduce the amount of data. The quality factor of a JPEG image relates to the precision of the samples. Sample precision can be reduced without visible detection.
The goal of the JPEG quality and smoothing values is to reduce the amount of data while maintaining a usable image. Depending on the JPEG, the compression is often in the range 9:1. A number between 1 and 100 specifies the tradeoff between size of the jpeg data and quality of the original image. A higher number will retain a higher quality but will not conserve as much bandwidth. If no value is specified then the FX Series value is inherited from a higher level policy; a default value of 25 is used if no higher level policy is defined. Images that have been transformed are typically not significantly changed by running through the algorithm again. What this means is that if an image has been compressed with particular smoothing and quality factor, if the same factors are used again, the image is not significantly changed.
GZIP compression is handled on-the-fly from the servers to the clients. This reduces bandwidth consumption and improves application delivery and client response time. The FX Series uses GZIP compression to reduce the payload size to deliver more data across the satellite link, enabling more applications to be delivered and the ability to support more users. GZIP compression removes non-essential information from data being moved from one location to another, and then reassembles the data to its original form after the transfer is complete.
Squeezing the data reduces network traffic and accelerates the delivery of time-sensitive information. GZIP compression uses standard techniques to compress data sent to browsers. While compression exists in many forms throughout Web deployments, the FX Series is able to more effectively apply compression resulting in better compression ratios. The most common use of compression in Web environments is accomplished by enabling GZIP functionality at the Web server. This is useful for reducing the text portions of pages, but GZIP is not normally used for attachment compression or for inbound compression from the browser. In addition, GZIP cannot be used to compress HTTP headers or image data.
Stampede utilizes various compression techniques to reduce the amount of data that must be sent across the network. In a single-sided mode, the FX Series appliance utilizes GZIP to compress information that can be processed by standard browsers. This is useful for reducing the text portions of pages, but GZIP is not normally used for attachment compression or for inbound compression from the browser. In addition, GZIP cannot be used to compress HTTP headers, cookies or image data. In two-sided deployment, the FX Series bi-directional compression provides compression for:
- All HTTP Headers
- Application Cookies
- All Text and Data Objects
- JPEG files with Image Reduction, yielding very acceptable quality
- All attachments and file uploads and downloads
Bandwidth pooling is used by satellite network service providers (SNSPs) to enforce a rate limit on traffic coming from their head-end out to different subnets. It allows SNSPs to define a pool, and associate a maximum bit-rate to that pool. With a defined pool, subnets are then identified as part of the pool. The FX Series enforces traffic limits based on the network administrator-defined throttle of the bandwidth pool so that the data going through the pool does not exceed the specified parameters.
A bandwidth pool consists of a record that includes a name, rate and subnet that belong to a specific pool. A SNSP can associate a carrier (or beam) to a bandwidth pool. In this case, a bandwidth pool corresponds to a specific satellite traffic beam. For network managers, the problem arises when assigning separate subnets over a single beam that may have any number of associated subnets.
The FX Series allows the administrator to restrict the data flow over a beam based on how they defined the subnets to their customers. This enables the administrator to apply QoS to the subnets, and have greater control over the re-transmission requirements for each subnet. This also alleviates the network architect or engineer from having to change each individual subnet, rather than having to individually shape each subnet so that all the subnets equal the total amount of bandwidth available for a single beam. The FX Series greatly simplifies this process by allowing network administrators to easily input the maximum rate for a particular beam (or carrier), and the subnets, and ensures that the traffic load will not exceed the rate. This also provides greater bandwidth flexibility by not enforcing an artificial rate limit on a per-subnet basis.
The FX Series takes traffic control to a new level. Stampede developed an easy-to-use Web GUI around the complex rate shaping technology that is built into the FX Series. With the Web GUI, network personnel are able to easily configure bandwidth pools. The FX Series Web GUI allows administrators to define a bandwidth pool and give it a rate, then add separate subnets to that pool. The FX Series appliance then dynamically throttles the traffic according to the specifications of the pool.
Connection management removes the burden of establishing and terminating TCP connections from the web servers, allowing the server to handle more traffic. Stampede manages network connections in several ways to optimize the flow of data and reduce the impact on the network, application servers and end-user devices. The FX Series appliance maintains a consistent pool of connections between itself and the servers. The servers are then offloaded from managing the connections, and are isolated from inadvertent session disconnects.
With Stampede’s FX Series Remote appliances working with the FX Series head-end appliance, a persistent connection between the client and server is always maintained, even when the browser may close and reopen a session. These sessions are also multiplexed across multiple connections, improving throughput and response time. This persistent connection is extremely important for AJAX and Web 2.0 applications which constantly open and close sessions as they poll and access various Web services. Stampede eliminates this potentially network intrusive overhead.
IP Source Preservation is a technology that is used to support security policies that require a specific source IP address, or range of IP addresses. It is also used to prevent the FX Series appliance from being blacklisted.
For example, in the event where a situation is deemed inappropriate, such as a SPAM event, the sending device Source IP address will be blacklisted. To avoid this problem, the FX Series uses the end-user’s Source IP address when making a request to a Web or application server. The FX Series configuration method makes implementing IP Source Preservation easy within a WCCP or inline environment. The FX Series is usually configured to use the IP address of the client when making requests to content servers, whereas, other acceleration devices make requests to Web servers using their own IP address. IP addressing problems can occur when, for example, an end-user is involved with illegal online activity and the IP address of the acceleration device is recorded in the Web server’s logs. If the IP address of the acceleration device is used to make the client request to the server, it will likely be placed on a blacklist, and therefore cause considerable network problems. By spoofing the IP address of the client, the FX Series is able to avoid this problem.
The Web Cache Communications Protocol (WCCP) allows satellite network service providers to transparently inject acceleration into their satellite network infrastructure by redirecting traffic flows in real-time to network devices such as the FX Series. WCCP has built-in load balancing, scaling, fault tolerance, and service-assurance (failsafe) mechanisms to ensure network devices can scale and have high-availability. For fault tolerance, if one of the FX Series appliances incurs a hardware failure, the WCCP-enabled router will stop sending traffic to that device and redirect traffic to the other FX Series appliances with zero down-time.
Load balancing via WCCP intelligently distributes the TCP and HTTP workload across multiple FX Series appliances. For flexible scalability, service providers can simply add an FX Series appliance to the cluster, and WCCP will split the traffic load among all the FX Series appliances. Up to thirty-two FX Series appliances can be set up within a cluster and dynamically load balanced.
WCCP enables network service providers to implement the FX Series into their network with greater deployment flexibility, without requiring the FX Series to be physically in-line. The FX Series can be deployed “virtually” in-line, hence, not all traffic is required to pass through the FX Series appliance. The network administrator programs the router to redirect traffic to the FX Service appliance in-bound and out-bound based on the router policies. This allows the administrators to make changes to their network environment by simply changing the router policies.
Stampede’s FX Series (running WCCP) localizes content, and responds to content requests in order to reduce the amount of data going over the WAN. This improves application delivery response times, and allows the WAN link to support more traffic. Using WCCP, traffic is transparently redirected to the FX series appliance for TCP and HTTP acceleration, compression, caching and other optimization services.
With WCCP configured, the router redirects traffic to the FX Series to perform the application acceleration and WAN optimization functions. When an end-user makes a request, the router intercepts the request, and redirects the request to the FX Series inside a generic routing encapsulation (GRE) frame to prevent any modifications to the original packet. The FX Series with WCCP can be used to transparently route traffic, so that you don’t have to make changes to Web browsers, and configure the FX Series as a proxy server to offload servers, accelerate application delivery and optimize the network.
Further demonstrating our technology leadership and innovation, we hold a number of patents.
Our patent-pending Automatic Carrier-in-Carrier Power Control (ACPC) mechanism solves the power control optimization problem in a very general way for CnC links. It provides a unique opportunity for modems on both sides of a CnC link to automatically measure and compensate for rain loss while maintaining a fixed PEB on the satellite during all conditions. In addition to automatically compensating for rain loss, ACPC also enables CnC modems to share link margin between modems (i.e. a modem experiencing clear sky conditions can effectively give excess link margin to a distant end modem experiencing rain conditions, thereby further enhancing overall availability). This feature is implemented using values measured by the modems and general rain model knowledge (i.e. a system level implementation is not required). The net effect of ACPC technology is a significant increase in effective link margin and availability for CnC links while ensuring no increase in the PEB at the satellite.
Adaptive Coding and Modulation is a statistical, non-static advantage that enables dynamic changes in user throughput. Benefits and value vary over time and are not guaranteed, but are predictable. ACM technology converts link margin to an increase in the data throughput of satellite links. When utilizing ACM operation in our modems and Advanced VSAT Solutions, link margin can be converted into increased throughput of satellite links.
AutoEQ supports amplitude and group delay equalization over the satellite system. When installed, it offers the ability to compensate the overall system group delay and amplitude flatness by pre-correcting the uplink carrier. This eliminates the need for external group delay/amplitude equalizers and makes possible equalization at L-Band.
AUPC is a feature whereby a local modem is permitted to adjust its own output power level in order to attempt to maintain the Eb/No at the remote modem. AUPC relies upon EDMAC for its operation. The remote modem constantly sends back information about the demodulator Eb/No using reserved bytes in the overhead structure. The local modem then compares this value of Eb/No with a pre-defined target value. If the Remote Eb/No is below the target, the local modem increases its output power, creating a closed-loop feedback system over the satellite link. A particularly attractive benefit of this feature is that whenever framed operation is selected, the remote demodulator’s Eb/No can be viewed from the front panel display of the local modem.
Satellite interference has a significant financial impact on both satellite operators and end users. We developed the MetaCarrier technology to address this severe, industry-wide challenge. The MetaCarrier technology embeds and detects a small message and unique ID within a video or data satellite carrier. This embedded message and ID significantly reduce the time to identify and clear interference sources. The MetaCarrier is embedded using spread spectrum techniques within the carrier itself without adding appreciable noise or power to the host carrier. The robust spread spectrum signal enables the host carrier to be identified even when the host carrier is well below another carrier or near the noise floor itself.
Our frequency converters utilize the patented “Daisy Chain” integrated switching technology. The Daisy Chain design removes the relays associated with a centralized protection switch tray and distributes them across the individual converters. We were awarded patent 5,666,646 on this distributed protection switch topology.
Our revolutionary and award-winning technology allows full duplex satellite links to transmit concurrently in the same segment of transponder bandwidth. When combined with the advanced forward error correction and modulation techniques in our modems, DoubleTalk Carrier-in-Carrier delivers improved satellite transponder utilization and unprecedented operating expense savings.
We added a new approach to continuously optimize satellite communication efficiency – Dynamic Predistortion (DPD) on the CDM-760. Working in tandem with DPD, a new crest factor reduction (CFR) technique is dynamically applied as well to further enhance performance. These innovative technologies, collectively labeled and referred to as DPD, create high signal integrity while operating the satellite transponder in the higher efficiency nonlinear region. They provide a significant increase in link margin, by as much as 2 dB, and/or in spectral efficiency, by as much as 6%.
Our Vipersat Management System (VMS) automates bandwidth utilization while optimizing space segment efficiency. The software allows intelligent management of satellite networks through system configuration and alarm management of the network. VMS is the engine that provides dynamic SCPC (dSCPC) bandwidth management of space segment.
Our EDMAC capability permits the users to access the M&C features of distant-end modems in a satellite link. This is accomplished by adding extra information to the user data in a manner that is completely transparent to the users.
Forward Error Correction is a powerful technique for improving the performance of error-prone channels found in communication systems. The performance of FECs can be evaluated based on their distance from Shannon limit. We offer traditional and advanced methods of forward error correction to improve performance of error-prone channels. Examples of our modems’ advanced FECs are:
- VersaFEC-2
- VersaFEC®
- Low-Density Parity-Check Codes (LDPCs)
- DVB-S, DVB-DSNG and DVB-S2
- 2nd Generation Turbo Product Codes (TPC)
Our modems are extremely flexible and powerful, and incorporate a large number of optional features that can be purchased at the initial order or while in the field. The FAST technology facilitates on-location upgrade of the operating feature set without removing a modem from the setup. With FAST technology, users have maximum flexibility for enabling functions as they are required. FAST allows a user to order a modem precisely tailored for the initial application. When service requirements change, the operator can upgrade the topology of the modem to meet those requirements within minutes. FAST permits the purchase and installation of options through special authorization codes loaded into the unit either via the front panel keypad or entered remotely via the remote port located on the modem rear panel. This accelerated upgrade can be accomplished because of FAST’s extensive use of the programmable logic devices incorporated into our products.
There are some applications where it becomes necessary, at the distant end of a satellite link, to provide a high-stability G.703 timing reference for timing equipment connected to the modem. For example, in cellular backhaul applications, the BTS equipment may require such a reference even though the satellite link itself may be operating at a data rate other than 1.544 Mbps or 2.048 Mbps. This is sometimes accomplished by adding a specialized GPS receiver at the distant end, which then provides the G.703 synchronizing signal. However, with the G.703 clock extension mode this may become unnecessary, as our modems with this feature – operating at either end of the link, where the local modem has access to a high-stability G.703 signal – can provide an almost perfect copy of this signal at the distant end. The presence of Doppler shift on the link is the only factor affecting the overall accuracy. If Doppler shift were not present, the copy of the clock would be perfect.
H-DNA is an evolutionary and dynamic network access technology designed for the Heights Networking Platform’s return links. It is fast, flexible and uncompromising, delivering unprecedented benefits to users and service providers alike.
Our advanced functionality allows for efficient IP networking and transport over satellite, and is available for select modems and the Advanced VSAT Series. Available options include header compression, payload compression, ultra low overhead streamline encapsulation and quality of service. When utilizing the advanced IP functionality, real-time traffic and other low priority traffic can seamlessly co-exist on the same link without impacting the voice quality or delivery of mission critical data. The functions provide high bandwidth efficiency, information security and simplified network design/configuration.
Our products utilize ASIC and FPGA modulator and demodulator designs, and support BPSK, QPSK, OQPSK, 8-PSK, 8-QAM, 16-QAM, 64-QAM, DVB-S2, 16-APSK and 32-APSK. Depending on the modem, demodulation is accomplished by either frequency conversion down to an intermediate frequency or directly down to base band with over sampling employed. Filtering is accomplished either by switched analog filters or digitally with polyphase FIR filters in the conversion FPGA. Due to the all-digital implementation with polyphase filters, designs are readily transferred to other data rates. Our modulation and demodulation technologies operate as low as 2.4 kbps to over 238 Mbps.
RAN Optimization can significantly reduce the satellite bandwidth required for cellular backhaul. It provides the user complete control over the desired level of optimization and link quality. The pre-emptive bandwidth management maintains superior voice and service quality even under WAN congestion. Depending on the traffic profile, typical bandwidth reduction of 30-35% can be achieved with little or no impact to the voice quality. RAN optimization is available in select modems, Memotec products and the Advanced VSAT Solutions.
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MCDD-100 Detecting Device SLM-5650BD Satellite Demodulator |
CDM-625A-ENI Advanced Satellite Modem | CDD-564AL IP Demodulators |
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WAN Optimization consists of two components, acceleration and optimization.
- Optimization – Reduces the amount of data that traverses the link by using compression and caching techniques. Provides traffic shaping on the link to allow different users and applications to get appropriate access.
- Acceleration – Gets the data to the user faster by reducing and overcoming the limitations of the underlying protocols. There is a natural synergy between acceleration and optimization. When the amount of data is reduced, it will also get there faster.
Featured Products
Active Products
Legacy Products
Legacy Products
Worldwide Authorized Service Centers
Asia
ChinaComtech Satellite Network Technologies, Inc. tel: +86-10-6808-0085/86/87
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IndiaComtech Satellite Network Technologies Inc. tel: +91-80-25245895 -97 Support Number: +91 99009-24365 |
IndiaSatcom Ground Systems Pvt. Ltd. tel: +91-80-2668-2523 fax: +91-80-2668-2524 |
- Medical insurance – choice of HMO / POS / HSA
- Dental insurance – choice of HMO / PPO
- Vision insurance
- Company paid life and Accidental Death and Dismemberment (AD&D) insurance
- Optional supplemental life and AD&D insurance
- Disability insurance – company paid short-term
- Optional supplemental short-term and long-term disability insurance
- Athletic club reimbursement
- 401(k) company match and automatic enrollment for all employees
- Employee stock purchase plan
- Tuition assistance
- Flexible spending account plan
- Paid vacation
- Paid personal time off
- 10 company paid holidays per year
- Sick leave
- Family leave
- Miscellaneous leave policies (military, jury duty, bereavement)
Traffic Prioritization shapes bandwidth utilization so that capacity requirements for mission-critical applications are always met. By controlling the transmission of specific applications, administrators are able to keep within bandwidth limits and to prioritize applications over satellite links.
Quality of Service (QoS) is used to classify and prioritize network applications based on business objectives to guarantee optimal application performance regardless of network conditions by assigning priority or bandwidth guarantees and limits for each application. Satellite links are subjected to limited amount of bandwidth. QoS traffic management enables network administrators to define preferential treatment for certain classes of traffic. For hub deployments, QoS provides TCP rate controls and priority levels capable of to supporting many remote sites, while, remote sites use QoS to prioritize applications and user types.
Even with proper QoS priorities in place, applications with large file transfers, such as CIFS, FTP, and backup systems can starve real-time applications such as VoIP and streaming media (e.g. video). Even if a real-time application has priority, the bulky nature of large-transfers takes too long to clear the satellite link – even when queuing and traffic shaping are enabled. The added latency that results can make a critical application such as VoIP impossible for many remote sites. To address this problem, Stampede’s FX Series reduces the size of data packets, and intelligently manages packets based on satellite link capability and application profiles.
The FX Series Traffic Shaping is a powerful feature which ensures on-time delivery of time-critical information. Through specific port assignments, priorities and policies that can be assigned at the database-level, guaranteeing Quality of Service for critical applications. The FX Series Traffic shaping feature allows different TCP ports to be assigned to individual applications, such as email and VoIP. These TCP ports are used in conjunction with Traffic Shaping hardware to provide different levels of service quality. This allows administrators to define the “Quality of Service” attributes used for traffic control based on either “Traffic Classes” or “Bandwidth Pools”.
Dynamic Data Suppression (DDS) is block level de-duplication, which is a technique for recognizing and replacing repetitive streams of payload data with signatures prior to transmission over the satellite links. DDS is not application protocol specific and can be applied to most TCP application traffic. The FX Series intelligently monitors the data stream and is able to distinguish protocol headers which change frequently from payload data which is often static. The FX Series extracts this payload data and segments it into blocks, storing each block into persistent memory known as a “byte cache”. Blocks of data are replaced with a signature for that data. This generates significant data reduction.
The FX Series provides application-aware modules for HTTP, HTTP/S, CIFS, MAPI, POP3, SMTP, and FTP that dramatically reduce costly handshakes and intelligently apply compression to lower bandwidth consumption and reduce latency.
Stampede specializes in optimizing protocols by consolidating multiple transactions into a single transaction, which eliminates round-trips, performing cache differencing on dynamically generated content, and bi-directional data compression. In addition, our patented technology (TurboStreaming) enables the transfer of previously compressed objects up to 5 times faster through intelligent multiplexing across multiple TCP sessions.
- TCP and HTTP applications have chatty protocols that put added delay in satellite networks, as do delay-sensitive applications such as VoIP and applications such as Microsoft Exchange and CIFS.
- IT managers are placing thousands of applications on their satellite links. Many of these applications are mission-critical, and compete over a limited amount of bandwidth.
Advanced Virtual Pipelining™ (AVP) is a technique developed by Stampede that provides 40% performance improvements for browser-based applications. This performance improvement is on top of the FX Series industry leading performance, and is only possible because of innovative technology for two-way application acceleration.It becomes an important and standard acceleration technique used with the FX Series family of products.
AVP is a highly optimized implementation of the patented TurboStreaming™ (multiplexed TCP sessions, patent # 7,543,072) that enables HTTP browser traffic to be intermixed across multiple “pipelines”. All browser activity is optimized, including the network-intensive polling associated with Web 2.0 and AJAX applications. A key advantage of our AVP implementation is that communication resources can be shared across multiple applications, and all HTTP requests and responses from any application (including multiple browsers) are intermixed simultaneously across multiple concurrent sessions. AVP serves as a platform for the consolidation and aggregation of all Web-based traffic from a given user. AVP logically aggregates multiple HTTP protocol streams across a few TCP sessions. Individual objects or pieces of objects can be split into any size and then multiplexed with other object data and reconstructed as needed SNSPs that deliver mixed payloads consisting of business-critical applications and data, streaming media, Voice Over Internet Protocol (VoIP) and other network-intensive traffic. The end result is improved throughput and faster response time for the end-user.
AVP enables the browser to open multiple pipelines (10s or even 100s) that communicate with the FX Series remote appliances. All of this data, from all browsers and all browser windows, is intelligently multiplexed over multiple TCP sessions (TurboStreaming) back to the head-end FX Series appliance. This fully utilizes all available bandwidth, and enables the browser to function at its full potential. This is only possible because of our advanced, industry leading two-sided acceleration technology.
The FX Series uses patented (PN# 6,012,085) “Multi-get” technology to reduce the chattiness of the HTTP protocol. In some cases, a single page retrieval will cause hundreds of HTTP Get requests to be issued by the browser.
A single page is returned to the browser that contains many embedded URLs needed for proper display of the original page. These URLs can be for additional HTML pages, image data such as pictures in the form of gifs and jpegs, java scripts and so on. The browser will first download the main page and then request the embedded URLs essentially one at a time. The latest browsers typically open several connections to retrieve these objects to overlap the retrieval process.
There are two problems with this approach. First, each item request causes a separate HTTP request/response round trip. For a first time retrieval of a page this may mean between 10 and 100 or more round trips to the Web server. More complicated pages can cause significantly more round trips. Secondly, the extra connections the browser uses can add significant load to a Web server and to the network infrastructure.
The FX Series Multi-get technology examines the first page when it is downloaded and builds a patented Multi-get request that contains an optimized “GET” for all of the necessary additional objects. The FX Series appliance parses this request and streams the objects to the remote FX Series appliance that caches them and returns them to the browser when the browser requests them. The FX Series Multi-get/Multi-verify technology determines which objects need to be retrieved freshly and which can be conditionally retrieved. All objects are retrieved in one logical request and streamed to the FX Series appliance.
The Multi-get/Multi-verify technology virtually eliminates the “chattiness” of the HTTP protocol. However, the Multi-get technology is not limited to HTML pages and is employed wherever possible; such as with JAVA Server Pages (JSPs) and Active Server Pages (ASPs) that have embedded Java Scripts. Advanced protocol optimizations drive significant improvements in bandwidth efficiencies and time savings, providing significant payload reductions and improved application delivery speeds. The FX Series specializes in optimizing the HTTP protocol by consolidating multiple transactions into a single transaction, which eliminates round-trips that add latency that can be responsible for up to 95% of the total application delay. Important protocols for satellite communications are HTTP (web mail, web surfing, enterprise web apps), POP3/ SMTP (email), HTTPS (enterprise accounts), CIFS (enterprise accounts). Stampede delivers true HTTP / HTTPS protocol optimization:
- Multi-get
- Content validation
- Intelligent cache-differencing, including dynamic content
- JPEG compression and smoothing
Intelligently caches Microsoft® Updates on the client side saving significant bandwidth attributed to “Patch Tuesday”. The FX Series caching methodology handles the rather complicated procedures employed by Microsoft and other AV vendors to request updates by requesting “partial objects”. This reduces the amount of data sent over satellite links to reduce bandwidth consumption and provide faster response times for end-users.
The FX Series Remote can dramatically curb bandwidth consumption by caching software updates published frequently by Microsoft, Symantic, Adobe, Apple and many other leading software vendors. Most Satellite service providers are aware of the bandwidth impact of “Patch Tuesday” – the day that Windows updates are distributed. The delivery of these updates is performed when software that resides on client devices downloads the new content in the background by requesting “partial content” over HTTP. The complex nature of “partial-content” HTTP requests thwarts the capabilities of most caching devices, however the FX Series Remote appliance caching engine can handle these requests. Once the content is cached by the FX Series Remote, subsequent retrievals by the updating agents that request “partial-content” will be satisfied by the FX Series Remote appliance, eliminating the need to repetitively transfer the same updates over satellite links.
The FX Series multiplexes large data objects using Stampede’s patented TurboStreaming™ (multiplexed TCP sessions, patent # 7,543,072) that enables HTTP browser traffic to be intermixed across multiple “pipelines”. All browser activity is optimized, including the network-intensive polling associated with Web 2.0 and AJAX applications. A key advantage of TurboStreaming is that communication resources can be shared across multiple applications, and all HTTP requests and responses from any application (including multiple browsers) are intermixed simultaneously across multiple concurrent sessions.
TurboStreaming serves as a platform for the consolidation and aggregation of all Web-based traffic from a given user. Multiple HTTP protocol streams are logically aggregated across a few TCP sessions. Individual objects or pieces of objects can be split into any size and then multiplexed with other object data and reconstructed as needed SNSPs that deliver mixed payloads consisting of business-critical applications and data, streaming media, Voice Over Internet Protocol (VoIP) and other network-intensive traffic. The end result is improved throughput and faster response time for the end-user.
TurboStreaming enables the browser to open multiple pipelines (10s or even 100s) that communicate with the FX Series remote appliances. All of this data, from all browsers and all browser windows, is intelligently multiplexed over multiple TCP sessions back to the head-end FX Series appliance. This fully utilizes all available bandwidth, and enables the browser to function at its full potential. This is only possible because of advanced, industry leading two-sided acceleration technology.
Caching brings information closer to the end-user by storing recently accessed data in local memory or on hard disk, reducing the time it takes to bring back needed information, making the user experience more positive and action oriented. While today’s browsers maintain their own cache, they tend to be overly conservative. This means they will err on the side of requesting a new piece of data or object, usually when it really hasn’t been changed. This not only impacts response time to the end-user, but also saturates bandwidth with unnecessary data transmission. Cache Differencing takes the concept one step further and maintains identical copies of the browser’s cache at the local device and on the FX Series appliance. The FX Series then uses intelligent differencing technology to understand what data has actually changed, and then transfers only the changed data. The local device functions normally, but with less data being transferred, you realize improved utilization of the satellite network, and increased end-user productivity.
Traditionally, pages can be marked as cacheable and will have expiration dates. When they expire they must be retrieved from the original server, resulting in additional traffic and data being transmitted across the satellite network. Within a two-sided environment, the FX Series remote appliance caches all pages returned to the browser (even pages that are marked as non-cacheable) and performs validation when needed to ensure that no stale data is returned to the browser. When the browser asks for a page or an item that has expired or been marked as non-cacheable, the FX Series remote appliance sends a validation request to the FX Series appliance at the head-end. If the FX Series appliance is aware of the last page the client cache contains and can compute differences in the page, it sends just the differences to an expired page or non-cached page. If the differences are too big, or if the FX Series appliance no longer has retained the last version that the client has, then the entire page is returned and subsequently cached for future possible differencing. The client in turn reconstructs the requested page, caches it, and returns it to the browser. Checksums are calculated by the FX Series appliance at the head-end and verified at the FX Series remote appliance so that pages will never be delivered incorrectly. While this technique adds value on expired pages, it is extremely effective for dynamic page generation.
An important aspect of Stampede’s Cache Differencing is the ability to perform differencing not only on HTML GET requests but also on POST requests. This is significant because a) responses to posts are always marked non-cacheable, and b) most applications that are based on SOAP and XML (including most AJAX applications) issue SOAP requests via the HTML POST command.
Advanced protocol optimizations drive significant improvements in bandwidth efficiencies and time savings (reducing payload and latency). WAN optimization and application acceleration technologies are deployed to improve satellite network performance and increase the amount of applications and users that can be delivered over the satellite link. The FX Series manages all TCP sessions, and handles the establishing and tearing down of TCP connections locally (at LAN speeds) to avoid satellite network congestion problems. This helps to increase link utilization and improve the user experience. TCP termination offloads the responsibility from servers having to handle the overhead imposed by the volume of TCP connections from web applications.
Additionally, application level multiplexed TCP streams take advantage of all other TCP or protocol optimization done at the link level, and application-level handshakes are eliminated by consolidating transaction requests.
Benefits include:
- Increases server capacity
- Reduces the amount of traffic sent over satellite links
- Keeps the satellite links maximized for optimum utilization
- Dramatically reduces transaction TCP turns (requests and responses) that bottleneck satellite links
For customers who use Microsoft’s Internet Explorer browser, the FX Series can reduce round trips during Internet sessions by marking the HTTP objects to allow IE to extend the time that the objects are stored within the browser cache without the content becoming stale.
Caching brings information closer to the end-user by storing recently accessed data in local memory or on hard disk, reducing the time it takes to bring back needed information, making the user experience more positive and action oriented. While today’s browsers maintain their own cache, they tend to be overly conservative. This means they will error on the side of requesting a new piece of data or object, usually when it really hasn’t been changed. This not only impacts response time to the end-user, but also saturates bandwidth with unnecessary data transmissions.
The FX Series uses caching to maintain copies of routinely accessed data to eliminate unnecessary requests to Web and application servers, and from going over limited satellite links. By keeping local copies of frequently requested content, the FX Series allows organizations to significantly reduce their upstream bandwidth usage and cost, while improving performance. The FX Series acts as an intermediary from end-users requesting content (such as a file, web page, or other resource) from servers. Some of the key benefits include:
- Reducing bandwidth consumption
- Keeping servers behind the FX Series anonymous for security purposes
- Delivering fast access to content
Image Reduction and Smoothing reduces the amount of data required to represent an image without significantly altering the visual perception of the image. This is accomplished in two ways. Smoothing reduces the high frequency components or the sharpness of an image. A moderate amount of smoothing can significantly reduce the amount of data. The quality factor of a JPEG image relates to the precision of the samples. Sample precision can be reduced without visible detection.
The goal of the JPEG quality and smoothing values is to reduce the amount of data while maintaining a usable image. Depending on the JPEG, the compression is often in the range 9:1. A number between 1 and 100 specifies the tradeoff between size of the jpeg data and quality of the original image. A higher number will retain a higher quality but will not conserve as much bandwidth. If no value is specified then the FX Series value is inherited from a higher level policy; a default value of 25 is used if no higher level policy is defined. Images that have been transformed are typically not significantly changed by running through the algorithm again. What this means is that if an image has been compressed with particular smoothing and quality factor, if the same factors are used again, the image is not significantly changed.
GZIP compression is handled on-the-fly from the servers to the clients. This reduces bandwidth consumption and improves application delivery and client response time. The FX Series uses GZIP compression to reduce the payload size to deliver more data across the satellite link, enabling more applications to be delivered and the ability to support more users. GZIP compression removes non-essential information from data being moved from one location to another, and then reassembles the data to its original form after the transfer is complete.
Squeezing the data reduces network traffic and accelerates the delivery of time-sensitive information. GZIP compression uses standard techniques to compress data sent to browsers. While compression exists in many forms throughout Web deployments, the FX Series is able to more effectively apply compression resulting in better compression ratios. The most common use of compression in Web environments is accomplished by enabling GZIP functionality at the Web server. This is useful for reducing the text portions of pages, but GZIP is not normally used for attachment compression or for inbound compression from the browser. In addition, GZIP cannot be used to compress HTTP headers or image data.
Stampede utilizes various compression techniques to reduce the amount of data that must be sent across the network. In a single-sided mode, the FX Series appliance utilizes GZIP to compress information that can be processed by standard browsers. This is useful for reducing the text portions of pages, but GZIP is not normally used for attachment compression or for inbound compression from the browser. In addition, GZIP cannot be used to compress HTTP headers, cookies or image data. In two-sided deployment, the FX Series bi-directional compression provides compression for:
- All HTTP Headers
- Application Cookies
- All Text and Data Objects
- JPEG files with Image Reduction, yielding very acceptable quality
- All attachments and file uploads and downloads
Bandwidth pooling is used by satellite network service providers (SNSPs) to enforce a rate limit on traffic coming from their head-end out to different subnets. It allows SNSPs to define a pool, and associate a maximum bit-rate to that pool. With a defined pool, subnets are then identified as part of the pool. The FX Series enforces traffic limits based on the network administrator-defined throttle of the bandwidth pool so that the data going through the pool does not exceed the specified parameters.
A bandwidth pool consists of a record that includes a name, rate and subnet that belong to a specific pool. A SNSP can associate a carrier (or beam) to a bandwidth pool. In this case, a bandwidth pool corresponds to a specific satellite traffic beam. For network managers, the problem arises when assigning separate subnets over a single beam that may have any number of associated subnets.
The FX Series allows the administrator to restrict the data flow over a beam based on how they defined the subnets to their customers. This enables the administrator to apply QoS to the subnets, and have greater control over the re-transmission requirements for each subnet. This also alleviates the network architect or engineer from having to change each individual subnet, rather than having to individually shape each subnet so that all the subnets equal the total amount of bandwidth available for a single beam. The FX Series greatly simplifies this process by allowing network administrators to easily input the maximum rate for a particular beam (or carrier), and the subnets, and ensures that the traffic load will not exceed the rate. This also provides greater bandwidth flexibility by not enforcing an artificial rate limit on a per-subnet basis.
The FX Series takes traffic control to a new level. Stampede developed an easy-to-use Web GUI around the complex rate shaping technology that is built into the FX Series. With the Web GUI, network personnel are able to easily configure bandwidth pools. The FX Series Web GUI allows administrators to define a bandwidth pool and give it a rate, then add separate subnets to that pool. The FX Series appliance then dynamically throttles the traffic according to the specifications of the pool.
Connection management removes the burden of establishing and terminating TCP connections from the web servers, allowing the server to handle more traffic. Stampede manages network connections in several ways to optimize the flow of data and reduce the impact on the network, application servers and end-user devices. The FX Series appliance maintains a consistent pool of connections between itself and the servers. The servers are then offloaded from managing the connections, and are isolated from inadvertent session disconnects.
With Stampede’s FX Series Remote appliances working with the FX Series head-end appliance, a persistent connection between the client and server is always maintained, even when the browser may close and reopen a session. These sessions are also multiplexed across multiple connections, improving throughput and response time. This persistent connection is extremely important for AJAX and Web 2.0 applications which constantly open and close sessions as they poll and access various Web services. Stampede eliminates this potentially network intrusive overhead.
IP Source Preservation is a technology that is used to support security policies that require a specific source IP address, or range of IP addresses. It is also used to prevent the FX Series appliance from being blacklisted.
For example, in the event where a situation is deemed inappropriate, such as a SPAM event, the sending device Source IP address will be blacklisted. To avoid this problem, the FX Series uses the end-user’s Source IP address when making a request to a Web or application server. The FX Series configuration method makes implementing IP Source Preservation easy within a WCCP or inline environment. The FX Series is usually configured to use the IP address of the client when making requests to content servers, whereas, other acceleration devices make requests to Web servers using their own IP address. IP addressing problems can occur when, for example, an end-user is involved with illegal online activity and the IP address of the acceleration device is recorded in the Web server’s logs. If the IP address of the acceleration device is used to make the client request to the server, it will likely be placed on a blacklist, and therefore cause considerable network problems. By spoofing the IP address of the client, the FX Series is able to avoid this problem.
The Web Cache Communications Protocol (WCCP) allows satellite network service providers to transparently inject acceleration into their satellite network infrastructure by redirecting traffic flows in real-time to network devices such as the FX Series. WCCP has built-in load balancing, scaling, fault tolerance, and service-assurance (failsafe) mechanisms to ensure network devices can scale and have high-availability. For fault tolerance, if one of the FX Series appliances incurs a hardware failure, the WCCP-enabled router will stop sending traffic to that device and redirect traffic to the other FX Series appliances with zero down-time.
Load balancing via WCCP intelligently distributes the TCP and HTTP workload across multiple FX Series appliances. For flexible scalability, service providers can simply add an FX Series appliance to the cluster, and WCCP will split the traffic load among all the FX Series appliances. Up to thirty-two FX Series appliances can be set up within a cluster and dynamically load balanced.
WCCP enables network service providers to implement the FX Series into their network with greater deployment flexibility, without requiring the FX Series to be physically in-line. The FX Series can be deployed “virtually” in-line, hence, not all traffic is required to pass through the FX Series appliance. The network administrator programs the router to redirect traffic to the FX Service appliance in-bound and out-bound based on the router policies. This allows the administrators to make changes to their network environment by simply changing the router policies.
Stampede’s FX Series (running WCCP) localizes content, and responds to content requests in order to reduce the amount of data going over the WAN. This improves application delivery response times, and allows the WAN link to support more traffic. Using WCCP, traffic is transparently redirected to the FX series appliance for TCP and HTTP acceleration, compression, caching and other optimization services.
With WCCP configured, the router redirects traffic to the FX Series to perform the application acceleration and WAN optimization functions. When an end-user makes a request, the router intercepts the request, and redirects the request to the FX Series inside a generic routing encapsulation (GRE) frame to prevent any modifications to the original packet. The FX Series with WCCP can be used to transparently route traffic, so that you don’t have to make changes to Web browsers, and configure the FX Series as a proxy server to offload servers, accelerate application delivery and optimize the network.
Further demonstrating our technology leadership and innovation, we hold a number of patents.
Our patent-pending Automatic Carrier-in-Carrier Power Control (ACPC) mechanism solves the power control optimization problem in a very general way for CnC links. It provides a unique opportunity for modems on both sides of a CnC link to automatically measure and compensate for rain loss while maintaining a fixed PEB on the satellite during all conditions. In addition to automatically compensating for rain loss, ACPC also enables CnC modems to share link margin between modems (i.e. a modem experiencing clear sky conditions can effectively give excess link margin to a distant end modem experiencing rain conditions, thereby further enhancing overall availability). This feature is implemented using values measured by the modems and general rain model knowledge (i.e. a system level implementation is not required). The net effect of ACPC technology is a significant increase in effective link margin and availability for CnC links while ensuring no increase in the PEB at the satellite.
Adaptive Coding and Modulation is a statistical, non-static advantage that enables dynamic changes in user throughput. Benefits and value vary over time and are not guaranteed, but are predictable. ACM technology converts link margin to an increase in the data throughput of satellite links. When utilizing ACM operation in our modems and Advanced VSAT Solutions, link margin can be converted into increased throughput of satellite links.
AutoEQ supports amplitude and group delay equalization over the satellite system. When installed, it offers the ability to compensate the overall system group delay and amplitude flatness by pre-correcting the uplink carrier. This eliminates the need for external group delay/amplitude equalizers and makes possible equalization at L-Band.
AUPC is a feature whereby a local modem is permitted to adjust its own output power level in order to attempt to maintain the Eb/No at the remote modem. AUPC relies upon EDMAC for its operation. The remote modem constantly sends back information about the demodulator Eb/No using reserved bytes in the overhead structure. The local modem then compares this value of Eb/No with a pre-defined target value. If the Remote Eb/No is below the target, the local modem increases its output power, creating a closed-loop feedback system over the satellite link. A particularly attractive benefit of this feature is that whenever framed operation is selected, the remote demodulator’s Eb/No can be viewed from the front panel display of the local modem.
Satellite interference has a significant financial impact on both satellite operators and end users. We developed the MetaCarrier technology to address this severe, industry-wide challenge. The MetaCarrier technology embeds and detects a small message and unique ID within a video or data satellite carrier. This embedded message and ID significantly reduce the time to identify and clear interference sources. The MetaCarrier is embedded using spread spectrum techniques within the carrier itself without adding appreciable noise or power to the host carrier. The robust spread spectrum signal enables the host carrier to be identified even when the host carrier is well below another carrier or near the noise floor itself.
Our frequency converters utilize the patented “Daisy Chain” integrated switching technology. The Daisy Chain design removes the relays associated with a centralized protection switch tray and distributes them across the individual converters. We were awarded patent 5,666,646 on this distributed protection switch topology.
Our revolutionary and award-winning technology allows full duplex satellite links to transmit concurrently in the same segment of transponder bandwidth. When combined with the advanced forward error correction and modulation techniques in our modems, DoubleTalk Carrier-in-Carrier delivers improved satellite transponder utilization and unprecedented operating expense savings.
We added a new approach to continuously optimize satellite communication efficiency – Dynamic Predistortion (DPD) on the CDM-760. Working in tandem with DPD, a new crest factor reduction (CFR) technique is dynamically applied as well to further enhance performance. These innovative technologies, collectively labeled and referred to as DPD, create high signal integrity while operating the satellite transponder in the higher efficiency nonlinear region. They provide a significant increase in link margin, by as much as 2 dB, and/or in spectral efficiency, by as much as 6%.
Our Vipersat Management System (VMS) automates bandwidth utilization while optimizing space segment efficiency. The software allows intelligent management of satellite networks through system configuration and alarm management of the network. VMS is the engine that provides dynamic SCPC (dSCPC) bandwidth management of space segment.
Our EDMAC capability permits the users to access the M&C features of distant-end modems in a satellite link. This is accomplished by adding extra information to the user data in a manner that is completely transparent to the users.
Forward Error Correction is a powerful technique for improving the performance of error-prone channels found in communication systems. The performance of FECs can be evaluated based on their distance from Shannon limit. We offer traditional and advanced methods of forward error correction to improve performance of error-prone channels. Examples of our modems’ advanced FECs are:
- VersaFEC-2
- VersaFEC®
- Low-Density Parity-Check Codes (LDPCs)
- DVB-S, DVB-DSNG and DVB-S2
- 2nd Generation Turbo Product Codes (TPC)
Our modems are extremely flexible and powerful, and incorporate a large number of optional features that can be purchased at the initial order or while in the field. The FAST technology facilitates on-location upgrade of the operating feature set without removing a modem from the setup. With FAST technology, users have maximum flexibility for enabling functions as they are required. FAST allows a user to order a modem precisely tailored for the initial application. When service requirements change, the operator can upgrade the topology of the modem to meet those requirements within minutes. FAST permits the purchase and installation of options through special authorization codes loaded into the unit either via the front panel keypad or entered remotely via the remote port located on the modem rear panel. This accelerated upgrade can be accomplished because of FAST’s extensive use of the programmable logic devices incorporated into our products.
There are some applications where it becomes necessary, at the distant end of a satellite link, to provide a high-stability G.703 timing reference for timing equipment connected to the modem. For example, in cellular backhaul applications, the BTS equipment may require such a reference even though the satellite link itself may be operating at a data rate other than 1.544 Mbps or 2.048 Mbps. This is sometimes accomplished by adding a specialized GPS receiver at the distant end, which then provides the G.703 synchronizing signal. However, with the G.703 clock extension mode this may become unnecessary, as our modems with this feature – operating at either end of the link, where the local modem has access to a high-stability G.703 signal – can provide an almost perfect copy of this signal at the distant end. The presence of Doppler shift on the link is the only factor affecting the overall accuracy. If Doppler shift were not present, the copy of the clock would be perfect.
H-DNA is an evolutionary and dynamic network access technology designed for the Heights Networking Platform’s return links. It is fast, flexible and uncompromising, delivering unprecedented benefits to users and service providers alike.
Our advanced functionality allows for efficient IP networking and transport over satellite, and is available for select modems and the Advanced VSAT Series. Available options include header compression, payload compression, ultra low overhead streamline encapsulation and quality of service. When utilizing the advanced IP functionality, real-time traffic and other low priority traffic can seamlessly co-exist on the same link without impacting the voice quality or delivery of mission critical data. The functions provide high bandwidth efficiency, information security and simplified network design/configuration.
Our products utilize ASIC and FPGA modulator and demodulator designs, and support BPSK, QPSK, OQPSK, 8-PSK, 8-QAM, 16-QAM, 64-QAM, DVB-S2, 16-APSK and 32-APSK. Depending on the modem, demodulation is accomplished by either frequency conversion down to an intermediate frequency or directly down to base band with over sampling employed. Filtering is accomplished either by switched analog filters or digitally with polyphase FIR filters in the conversion FPGA. Due to the all-digital implementation with polyphase filters, designs are readily transferred to other data rates. Our modulation and demodulation technologies operate as low as 2.4 kbps to over 238 Mbps.
RAN Optimization can significantly reduce the satellite bandwidth required for cellular backhaul. It provides the user complete control over the desired level of optimization and link quality. The pre-emptive bandwidth management maintains superior voice and service quality even under WAN congestion. Depending on the traffic profile, typical bandwidth reduction of 30-35% can be achieved with little or no impact to the voice quality. RAN optimization is available in select modems, Memotec products and the Advanced VSAT Solutions.
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WAN Optimization consists of two components, acceleration and optimization.
- Optimization – Reduces the amount of data that traverses the link by using compression and caching techniques. Provides traffic shaping on the link to allow different users and applications to get appropriate access.
- Acceleration – Gets the data to the user faster by reducing and overcoming the limitations of the underlying protocols. There is a natural synergy between acceleration and optimization. When the amount of data is reduced, it will also get there faster.
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Sematron UK, Ltd.
Sandpiper House, Aviary Court,
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Hampshire RG24 8GX
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- Medical insurance – choice of HMO / POS / HSA
- Dental insurance – choice of HMO / PPO
- Vision insurance
- Company paid life and Accidental Death and Dismemberment (AD&D) insurance
- Optional supplemental life and AD&D insurance
- Disability insurance – company paid short-term
- Optional supplemental short-term and long-term disability insurance
- Athletic club reimbursement
- 401(k) company match and automatic enrollment for all employees
- Employee stock purchase plan
- Tuition assistance
- Flexible spending account plan
- Paid vacation
- Paid personal time off
- 10 company paid holidays per year
- Sick leave
- Family leave
- Miscellaneous leave policies (military, jury duty, bereavement)
Traffic Prioritization shapes bandwidth utilization so that capacity requirements for mission-critical applications are always met. By controlling the transmission of specific applications, administrators are able to keep within bandwidth limits and to prioritize applications over satellite links.
Quality of Service (QoS) is used to classify and prioritize network applications based on business objectives to guarantee optimal application performance regardless of network conditions by assigning priority or bandwidth guarantees and limits for each application. Satellite links are subjected to limited amount of bandwidth. QoS traffic management enables network administrators to define preferential treatment for certain classes of traffic. For hub deployments, QoS provides TCP rate controls and priority levels capable of to supporting many remote sites, while, remote sites use QoS to prioritize applications and user types.
Even with proper QoS priorities in place, applications with large file transfers, such as CIFS, FTP, and backup systems can starve real-time applications such as VoIP and streaming media (e.g. video). Even if a real-time application has priority, the bulky nature of large-transfers takes too long to clear the satellite link – even when queuing and traffic shaping are enabled. The added latency that results can make a critical application such as VoIP impossible for many remote sites. To address this problem, Stampede’s FX Series reduces the size of data packets, and intelligently manages packets based on satellite link capability and application profiles.
The FX Series Traffic Shaping is a powerful feature which ensures on-time delivery of time-critical information. Through specific port assignments, priorities and policies that can be assigned at the database-level, guaranteeing Quality of Service for critical applications. The FX Series Traffic shaping feature allows different TCP ports to be assigned to individual applications, such as email and VoIP. These TCP ports are used in conjunction with Traffic Shaping hardware to provide different levels of service quality. This allows administrators to define the “Quality of Service” attributes used for traffic control based on either “Traffic Classes” or “Bandwidth Pools”.
Dynamic Data Suppression (DDS) is block level de-duplication, which is a technique for recognizing and replacing repetitive streams of payload data with signatures prior to transmission over the satellite links. DDS is not application protocol specific and can be applied to most TCP application traffic. The FX Series intelligently monitors the data stream and is able to distinguish protocol headers which change frequently from payload data which is often static. The FX Series extracts this payload data and segments it into blocks, storing each block into persistent memory known as a “byte cache”. Blocks of data are replaced with a signature for that data. This generates significant data reduction.
The FX Series provides application-aware modules for HTTP, HTTP/S, CIFS, MAPI, POP3, SMTP, and FTP that dramatically reduce costly handshakes and intelligently apply compression to lower bandwidth consumption and reduce latency.
Stampede specializes in optimizing protocols by consolidating multiple transactions into a single transaction, which eliminates round-trips, performing cache differencing on dynamically generated content, and bi-directional data compression. In addition, our patented technology (TurboStreaming) enables the transfer of previously compressed objects up to 5 times faster through intelligent multiplexing across multiple TCP sessions.
- TCP and HTTP applications have chatty protocols that put added delay in satellite networks, as do delay-sensitive applications such as VoIP and applications such as Microsoft Exchange and CIFS.
- IT managers are placing thousands of applications on their satellite links. Many of these applications are mission-critical, and compete over a limited amount of bandwidth.
Advanced Virtual Pipelining™ (AVP) is a technique developed by Stampede that provides 40% performance improvements for browser-based applications. This performance improvement is on top of the FX Series industry leading performance, and is only possible because of innovative technology for two-way application acceleration.It becomes an important and standard acceleration technique used with the FX Series family of products.
AVP is a highly optimized implementation of the patented TurboStreaming™ (multiplexed TCP sessions, patent # 7,543,072) that enables HTTP browser traffic to be intermixed across multiple “pipelines”. All browser activity is optimized, including the network-intensive polling associated with Web 2.0 and AJAX applications. A key advantage of our AVP implementation is that communication resources can be shared across multiple applications, and all HTTP requests and responses from any application (including multiple browsers) are intermixed simultaneously across multiple concurrent sessions. AVP serves as a platform for the consolidation and aggregation of all Web-based traffic from a given user. AVP logically aggregates multiple HTTP protocol streams across a few TCP sessions. Individual objects or pieces of objects can be split into any size and then multiplexed with other object data and reconstructed as needed SNSPs that deliver mixed payloads consisting of business-critical applications and data, streaming media, Voice Over Internet Protocol (VoIP) and other network-intensive traffic. The end result is improved throughput and faster response time for the end-user.
AVP enables the browser to open multiple pipelines (10s or even 100s) that communicate with the FX Series remote appliances. All of this data, from all browsers and all browser windows, is intelligently multiplexed over multiple TCP sessions (TurboStreaming) back to the head-end FX Series appliance. This fully utilizes all available bandwidth, and enables the browser to function at its full potential. This is only possible because of our advanced, industry leading two-sided acceleration technology.
The FX Series uses patented (PN# 6,012,085) “Multi-get” technology to reduce the chattiness of the HTTP protocol. In some cases, a single page retrieval will cause hundreds of HTTP Get requests to be issued by the browser.
A single page is returned to the browser that contains many embedded URLs needed for proper display of the original page. These URLs can be for additional HTML pages, image data such as pictures in the form of gifs and jpegs, java scripts and so on. The browser will first download the main page and then request the embedded URLs essentially one at a time. The latest browsers typically open several connections to retrieve these objects to overlap the retrieval process.
There are two problems with this approach. First, each item request causes a separate HTTP request/response round trip. For a first time retrieval of a page this may mean between 10 and 100 or more round trips to the Web server. More complicated pages can cause significantly more round trips. Secondly, the extra connections the browser uses can add significant load to a Web server and to the network infrastructure.
The FX Series Multi-get technology examines the first page when it is downloaded and builds a patented Multi-get request that contains an optimized “GET” for all of the necessary additional objects. The FX Series appliance parses this request and streams the objects to the remote FX Series appliance that caches them and returns them to the browser when the browser requests them. The FX Series Multi-get/Multi-verify technology determines which objects need to be retrieved freshly and which can be conditionally retrieved. All objects are retrieved in one logical request and streamed to the FX Series appliance.
The Multi-get/Multi-verify technology virtually eliminates the “chattiness” of the HTTP protocol. However, the Multi-get technology is not limited to HTML pages and is employed wherever possible; such as with JAVA Server Pages (JSPs) and Active Server Pages (ASPs) that have embedded Java Scripts. Advanced protocol optimizations drive significant improvements in bandwidth efficiencies and time savings, providing significant payload reductions and improved application delivery speeds. The FX Series specializes in optimizing the HTTP protocol by consolidating multiple transactions into a single transaction, which eliminates round-trips that add latency that can be responsible for up to 95% of the total application delay. Important protocols for satellite communications are HTTP (web mail, web surfing, enterprise web apps), POP3/ SMTP (email), HTTPS (enterprise accounts), CIFS (enterprise accounts). Stampede delivers true HTTP / HTTPS protocol optimization:
- Multi-get
- Content validation
- Intelligent cache-differencing, including dynamic content
- JPEG compression and smoothing
Intelligently caches Microsoft® Updates on the client side saving significant bandwidth attributed to “Patch Tuesday”. The FX Series caching methodology handles the rather complicated procedures employed by Microsoft and other AV vendors to request updates by requesting “partial objects”. This reduces the amount of data sent over satellite links to reduce bandwidth consumption and provide faster response times for end-users.
The FX Series Remote can dramatically curb bandwidth consumption by caching software updates published frequently by Microsoft, Symantic, Adobe, Apple and many other leading software vendors. Most Satellite service providers are aware of the bandwidth impact of “Patch Tuesday” – the day that Windows updates are distributed. The delivery of these updates is performed when software that resides on client devices downloads the new content in the background by requesting “partial content” over HTTP. The complex nature of “partial-content” HTTP requests thwarts the capabilities of most caching devices, however the FX Series Remote appliance caching engine can handle these requests. Once the content is cached by the FX Series Remote, subsequent retrievals by the updating agents that request “partial-content” will be satisfied by the FX Series Remote appliance, eliminating the need to repetitively transfer the same updates over satellite links.
The FX Series multiplexes large data objects using Stampede’s patented TurboStreaming™ (multiplexed TCP sessions, patent # 7,543,072) that enables HTTP browser traffic to be intermixed across multiple “pipelines”. All browser activity is optimized, including the network-intensive polling associated with Web 2.0 and AJAX applications. A key advantage of TurboStreaming is that communication resources can be shared across multiple applications, and all HTTP requests and responses from any application (including multiple browsers) are intermixed simultaneously across multiple concurrent sessions.
TurboStreaming serves as a platform for the consolidation and aggregation of all Web-based traffic from a given user. Multiple HTTP protocol streams are logically aggregated across a few TCP sessions. Individual objects or pieces of objects can be split into any size and then multiplexed with other object data and reconstructed as needed SNSPs that deliver mixed payloads consisting of business-critical applications and data, streaming media, Voice Over Internet Protocol (VoIP) and other network-intensive traffic. The end result is improved throughput and faster response time for the end-user.
TurboStreaming enables the browser to open multiple pipelines (10s or even 100s) that communicate with the FX Series remote appliances. All of this data, from all browsers and all browser windows, is intelligently multiplexed over multiple TCP sessions back to the head-end FX Series appliance. This fully utilizes all available bandwidth, and enables the browser to function at its full potential. This is only possible because of advanced, industry leading two-sided acceleration technology.
Caching brings information closer to the end-user by storing recently accessed data in local memory or on hard disk, reducing the time it takes to bring back needed information, making the user experience more positive and action oriented. While today’s browsers maintain their own cache, they tend to be overly conservative. This means they will err on the side of requesting a new piece of data or object, usually when it really hasn’t been changed. This not only impacts response time to the end-user, but also saturates bandwidth with unnecessary data transmission. Cache Differencing takes the concept one step further and maintains identical copies of the browser’s cache at the local device and on the FX Series appliance. The FX Series then uses intelligent differencing technology to understand what data has actually changed, and then transfers only the changed data. The local device functions normally, but with less data being transferred, you realize improved utilization of the satellite network, and increased end-user productivity.
Traditionally, pages can be marked as cacheable and will have expiration dates. When they expire they must be retrieved from the original server, resulting in additional traffic and data being transmitted across the satellite network. Within a two-sided environment, the FX Series remote appliance caches all pages returned to the browser (even pages that are marked as non-cacheable) and performs validation when needed to ensure that no stale data is returned to the browser. When the browser asks for a page or an item that has expired or been marked as non-cacheable, the FX Series remote appliance sends a validation request to the FX Series appliance at the head-end. If the FX Series appliance is aware of the last page the client cache contains and can compute differences in the page, it sends just the differences to an expired page or non-cached page. If the differences are too big, or if the FX Series appliance no longer has retained the last version that the client has, then the entire page is returned and subsequently cached for future possible differencing. The client in turn reconstructs the requested page, caches it, and returns it to the browser. Checksums are calculated by the FX Series appliance at the head-end and verified at the FX Series remote appliance so that pages will never be delivered incorrectly. While this technique adds value on expired pages, it is extremely effective for dynamic page generation.
An important aspect of Stampede’s Cache Differencing is the ability to perform differencing not only on HTML GET requests but also on POST requests. This is significant because a) responses to posts are always marked non-cacheable, and b) most applications that are based on SOAP and XML (including most AJAX applications) issue SOAP requests via the HTML POST command.
Advanced protocol optimizations drive significant improvements in bandwidth efficiencies and time savings (reducing payload and latency). WAN optimization and application acceleration technologies are deployed to improve satellite network performance and increase the amount of applications and users that can be delivered over the satellite link. The FX Series manages all TCP sessions, and handles the establishing and tearing down of TCP connections locally (at LAN speeds) to avoid satellite network congestion problems. This helps to increase link utilization and improve the user experience. TCP termination offloads the responsibility from servers having to handle the overhead imposed by the volume of TCP connections from web applications.
Additionally, application level multiplexed TCP streams take advantage of all other TCP or protocol optimization done at the link level, and application-level handshakes are eliminated by consolidating transaction requests.
Benefits include:
- Increases server capacity
- Reduces the amount of traffic sent over satellite links
- Keeps the satellite links maximized for optimum utilization
- Dramatically reduces transaction TCP turns (requests and responses) that bottleneck satellite links
For customers who use Microsoft’s Internet Explorer browser, the FX Series can reduce round trips during Internet sessions by marking the HTTP objects to allow IE to extend the time that the objects are stored within the browser cache without the content becoming stale.
Caching brings information closer to the end-user by storing recently accessed data in local memory or on hard disk, reducing the time it takes to bring back needed information, making the user experience more positive and action oriented. While today’s browsers maintain their own cache, they tend to be overly conservative. This means they will error on the side of requesting a new piece of data or object, usually when it really hasn’t been changed. This not only impacts response time to the end-user, but also saturates bandwidth with unnecessary data transmissions.
The FX Series uses caching to maintain copies of routinely accessed data to eliminate unnecessary requests to Web and application servers, and from going over limited satellite links. By keeping local copies of frequently requested content, the FX Series allows organizations to significantly reduce their upstream bandwidth usage and cost, while improving performance. The FX Series acts as an intermediary from end-users requesting content (such as a file, web page, or other resource) from servers. Some of the key benefits include:
- Reducing bandwidth consumption
- Keeping servers behind the FX Series anonymous for security purposes
- Delivering fast access to content
Image Reduction and Smoothing reduces the amount of data required to represent an image without significantly altering the visual perception of the image. This is accomplished in two ways. Smoothing reduces the high frequency components or the sharpness of an image. A moderate amount of smoothing can significantly reduce the amount of data. The quality factor of a JPEG image relates to the precision of the samples. Sample precision can be reduced without visible detection.
The goal of the JPEG quality and smoothing values is to reduce the amount of data while maintaining a usable image. Depending on the JPEG, the compression is often in the range 9:1. A number between 1 and 100 specifies the tradeoff between size of the jpeg data and quality of the original image. A higher number will retain a higher quality but will not conserve as much bandwidth. If no value is specified then the FX Series value is inherited from a higher level policy; a default value of 25 is used if no higher level policy is defined. Images that have been transformed are typically not significantly changed by running through the algorithm again. What this means is that if an image has been compressed with particular smoothing and quality factor, if the same factors are used again, the image is not significantly changed.
GZIP compression is handled on-the-fly from the servers to the clients. This reduces bandwidth consumption and improves application delivery and client response time. The FX Series uses GZIP compression to reduce the payload size to deliver more data across the satellite link, enabling more applications to be delivered and the ability to support more users. GZIP compression removes non-essential information from data being moved from one location to another, and then reassembles the data to its original form after the transfer is complete.
Squeezing the data reduces network traffic and accelerates the delivery of time-sensitive information. GZIP compression uses standard techniques to compress data sent to browsers. While compression exists in many forms throughout Web deployments, the FX Series is able to more effectively apply compression resulting in better compression ratios. The most common use of compression in Web environments is accomplished by enabling GZIP functionality at the Web server. This is useful for reducing the text portions of pages, but GZIP is not normally used for attachment compression or for inbound compression from the browser. In addition, GZIP cannot be used to compress HTTP headers or image data.
Stampede utilizes various compression techniques to reduce the amount of data that must be sent across the network. In a single-sided mode, the FX Series appliance utilizes GZIP to compress information that can be processed by standard browsers. This is useful for reducing the text portions of pages, but GZIP is not normally used for attachment compression or for inbound compression from the browser. In addition, GZIP cannot be used to compress HTTP headers, cookies or image data. In two-sided deployment, the FX Series bi-directional compression provides compression for:
- All HTTP Headers
- Application Cookies
- All Text and Data Objects
- JPEG files with Image Reduction, yielding very acceptable quality
- All attachments and file uploads and downloads
Bandwidth pooling is used by satellite network service providers (SNSPs) to enforce a rate limit on traffic coming from their head-end out to different subnets. It allows SNSPs to define a pool, and associate a maximum bit-rate to that pool. With a defined pool, subnets are then identified as part of the pool. The FX Series enforces traffic limits based on the network administrator-defined throttle of the bandwidth pool so that the data going through the pool does not exceed the specified parameters.
A bandwidth pool consists of a record that includes a name, rate and subnet that belong to a specific pool. A SNSP can associate a carrier (or beam) to a bandwidth pool. In this case, a bandwidth pool corresponds to a specific satellite traffic beam. For network managers, the problem arises when assigning separate subnets over a single beam that may have any number of associated subnets.
The FX Series allows the administrator to restrict the data flow over a beam based on how they defined the subnets to their customers. This enables the administrator to apply QoS to the subnets, and have greater control over the re-transmission requirements for each subnet. This also alleviates the network architect or engineer from having to change each individual subnet, rather than having to individually shape each subnet so that all the subnets equal the total amount of bandwidth available for a single beam. The FX Series greatly simplifies this process by allowing network administrators to easily input the maximum rate for a particular beam (or carrier), and the subnets, and ensures that the traffic load will not exceed the rate. This also provides greater bandwidth flexibility by not enforcing an artificial rate limit on a per-subnet basis.
The FX Series takes traffic control to a new level. Stampede developed an easy-to-use Web GUI around the complex rate shaping technology that is built into the FX Series. With the Web GUI, network personnel are able to easily configure bandwidth pools. The FX Series Web GUI allows administrators to define a bandwidth pool and give it a rate, then add separate subnets to that pool. The FX Series appliance then dynamically throttles the traffic according to the specifications of the pool.
Connection management removes the burden of establishing and terminating TCP connections from the web servers, allowing the server to handle more traffic. Stampede manages network connections in several ways to optimize the flow of data and reduce the impact on the network, application servers and end-user devices. The FX Series appliance maintains a consistent pool of connections between itself and the servers. The servers are then offloaded from managing the connections, and are isolated from inadvertent session disconnects.
With Stampede’s FX Series Remote appliances working with the FX Series head-end appliance, a persistent connection between the client and server is always maintained, even when the browser may close and reopen a session. These sessions are also multiplexed across multiple connections, improving throughput and response time. This persistent connection is extremely important for AJAX and Web 2.0 applications which constantly open and close sessions as they poll and access various Web services. Stampede eliminates this potentially network intrusive overhead.
IP Source Preservation is a technology that is used to support security policies that require a specific source IP address, or range of IP addresses. It is also used to prevent the FX Series appliance from being blacklisted.
For example, in the event where a situation is deemed inappropriate, such as a SPAM event, the sending device Source IP address will be blacklisted. To avoid this problem, the FX Series uses the end-user’s Source IP address when making a request to a Web or application server. The FX Series configuration method makes implementing IP Source Preservation easy within a WCCP or inline environment. The FX Series is usually configured to use the IP address of the client when making requests to content servers, whereas, other acceleration devices make requests to Web servers using their own IP address. IP addressing problems can occur when, for example, an end-user is involved with illegal online activity and the IP address of the acceleration device is recorded in the Web server’s logs. If the IP address of the acceleration device is used to make the client request to the server, it will likely be placed on a blacklist, and therefore cause considerable network problems. By spoofing the IP address of the client, the FX Series is able to avoid this problem.
The Web Cache Communications Protocol (WCCP) allows satellite network service providers to transparently inject acceleration into their satellite network infrastructure by redirecting traffic flows in real-time to network devices such as the FX Series. WCCP has built-in load balancing, scaling, fault tolerance, and service-assurance (failsafe) mechanisms to ensure network devices can scale and have high-availability. For fault tolerance, if one of the FX Series appliances incurs a hardware failure, the WCCP-enabled router will stop sending traffic to that device and redirect traffic to the other FX Series appliances with zero down-time.
Load balancing via WCCP intelligently distributes the TCP and HTTP workload across multiple FX Series appliances. For flexible scalability, service providers can simply add an FX Series appliance to the cluster, and WCCP will split the traffic load among all the FX Series appliances. Up to thirty-two FX Series appliances can be set up within a cluster and dynamically load balanced.
WCCP enables network service providers to implement the FX Series into their network with greater deployment flexibility, without requiring the FX Series to be physically in-line. The FX Series can be deployed “virtually” in-line, hence, not all traffic is required to pass through the FX Series appliance. The network administrator programs the router to redirect traffic to the FX Service appliance in-bound and out-bound based on the router policies. This allows the administrators to make changes to their network environment by simply changing the router policies.
Stampede’s FX Series (running WCCP) localizes content, and responds to content requests in order to reduce the amount of data going over the WAN. This improves application delivery response times, and allows the WAN link to support more traffic. Using WCCP, traffic is transparently redirected to the FX series appliance for TCP and HTTP acceleration, compression, caching and other optimization services.
With WCCP configured, the router redirects traffic to the FX Series to perform the application acceleration and WAN optimization functions. When an end-user makes a request, the router intercepts the request, and redirects the request to the FX Series inside a generic routing encapsulation (GRE) frame to prevent any modifications to the original packet. The FX Series with WCCP can be used to transparently route traffic, so that you don’t have to make changes to Web browsers, and configure the FX Series as a proxy server to offload servers, accelerate application delivery and optimize the network.
Further demonstrating our technology leadership and innovation, we hold a number of patents.
Our patent-pending Automatic Carrier-in-Carrier Power Control (ACPC) mechanism solves the power control optimization problem in a very general way for CnC links. It provides a unique opportunity for modems on both sides of a CnC link to automatically measure and compensate for rain loss while maintaining a fixed PEB on the satellite during all conditions. In addition to automatically compensating for rain loss, ACPC also enables CnC modems to share link margin between modems (i.e. a modem experiencing clear sky conditions can effectively give excess link margin to a distant end modem experiencing rain conditions, thereby further enhancing overall availability). This feature is implemented using values measured by the modems and general rain model knowledge (i.e. a system level implementation is not required). The net effect of ACPC technology is a significant increase in effective link margin and availability for CnC links while ensuring no increase in the PEB at the satellite.
Adaptive Coding and Modulation is a statistical, non-static advantage that enables dynamic changes in user throughput. Benefits and value vary over time and are not guaranteed, but are predictable. ACM technology converts link margin to an increase in the data throughput of satellite links. When utilizing ACM operation in our modems and Advanced VSAT Solutions, link margin can be converted into increased throughput of satellite links.
AutoEQ supports amplitude and group delay equalization over the satellite system. When installed, it offers the ability to compensate the overall system group delay and amplitude flatness by pre-correcting the uplink carrier. This eliminates the need for external group delay/amplitude equalizers and makes possible equalization at L-Band.
AUPC is a feature whereby a local modem is permitted to adjust its own output power level in order to attempt to maintain the Eb/No at the remote modem. AUPC relies upon EDMAC for its operation. The remote modem constantly sends back information about the demodulator Eb/No using reserved bytes in the overhead structure. The local modem then compares this value of Eb/No with a pre-defined target value. If the Remote Eb/No is below the target, the local modem increases its output power, creating a closed-loop feedback system over the satellite link. A particularly attractive benefit of this feature is that whenever framed operation is selected, the remote demodulator’s Eb/No can be viewed from the front panel display of the local modem.
Satellite interference has a significant financial impact on both satellite operators and end users. We developed the MetaCarrier technology to address this severe, industry-wide challenge. The MetaCarrier technology embeds and detects a small message and unique ID within a video or data satellite carrier. This embedded message and ID significantly reduce the time to identify and clear interference sources. The MetaCarrier is embedded using spread spectrum techniques within the carrier itself without adding appreciable noise or power to the host carrier. The robust spread spectrum signal enables the host carrier to be identified even when the host carrier is well below another carrier or near the noise floor itself.
Our frequency converters utilize the patented “Daisy Chain” integrated switching technology. The Daisy Chain design removes the relays associated with a centralized protection switch tray and distributes them across the individual converters. We were awarded patent 5,666,646 on this distributed protection switch topology.
Our revolutionary and award-winning technology allows full duplex satellite links to transmit concurrently in the same segment of transponder bandwidth. When combined with the advanced forward error correction and modulation techniques in our modems, DoubleTalk Carrier-in-Carrier delivers improved satellite transponder utilization and unprecedented operating expense savings.
We added a new approach to continuously optimize satellite communication efficiency – Dynamic Predistortion (DPD) on the CDM-760. Working in tandem with DPD, a new crest factor reduction (CFR) technique is dynamically applied as well to further enhance performance. These innovative technologies, collectively labeled and referred to as DPD, create high signal integrity while operating the satellite transponder in the higher efficiency nonlinear region. They provide a significant increase in link margin, by as much as 2 dB, and/or in spectral efficiency, by as much as 6%.
Our Vipersat Management System (VMS) automates bandwidth utilization while optimizing space segment efficiency. The software allows intelligent management of satellite networks through system configuration and alarm management of the network. VMS is the engine that provides dynamic SCPC (dSCPC) bandwidth management of space segment.
Our EDMAC capability permits the users to access the M&C features of distant-end modems in a satellite link. This is accomplished by adding extra information to the user data in a manner that is completely transparent to the users.
Forward Error Correction is a powerful technique for improving the performance of error-prone channels found in communication systems. The performance of FECs can be evaluated based on their distance from Shannon limit. We offer traditional and advanced methods of forward error correction to improve performance of error-prone channels. Examples of our modems’ advanced FECs are:
- VersaFEC-2
- VersaFEC®
- Low-Density Parity-Check Codes (LDPCs)
- DVB-S, DVB-DSNG and DVB-S2
- 2nd Generation Turbo Product Codes (TPC)
Our modems are extremely flexible and powerful, and incorporate a large number of optional features that can be purchased at the initial order or while in the field. The FAST technology facilitates on-location upgrade of the operating feature set without removing a modem from the setup. With FAST technology, users have maximum flexibility for enabling functions as they are required. FAST allows a user to order a modem precisely tailored for the initial application. When service requirements change, the operator can upgrade the topology of the modem to meet those requirements within minutes. FAST permits the purchase and installation of options through special authorization codes loaded into the unit either via the front panel keypad or entered remotely via the remote port located on the modem rear panel. This accelerated upgrade can be accomplished because of FAST’s extensive use of the programmable logic devices incorporated into our products.
There are some applications where it becomes necessary, at the distant end of a satellite link, to provide a high-stability G.703 timing reference for timing equipment connected to the modem. For example, in cellular backhaul applications, the BTS equipment may require such a reference even though the satellite link itself may be operating at a data rate other than 1.544 Mbps or 2.048 Mbps. This is sometimes accomplished by adding a specialized GPS receiver at the distant end, which then provides the G.703 synchronizing signal. However, with the G.703 clock extension mode this may become unnecessary, as our modems with this feature – operating at either end of the link, where the local modem has access to a high-stability G.703 signal – can provide an almost perfect copy of this signal at the distant end. The presence of Doppler shift on the link is the only factor affecting the overall accuracy. If Doppler shift were not present, the copy of the clock would be perfect.
H-DNA is an evolutionary and dynamic network access technology designed for the Heights Networking Platform’s return links. It is fast, flexible and uncompromising, delivering unprecedented benefits to users and service providers alike.
Our advanced functionality allows for efficient IP networking and transport over satellite, and is available for select modems and the Advanced VSAT Series. Available options include header compression, payload compression, ultra low overhead streamline encapsulation and quality of service. When utilizing the advanced IP functionality, real-time traffic and other low priority traffic can seamlessly co-exist on the same link without impacting the voice quality or delivery of mission critical data. The functions provide high bandwidth efficiency, information security and simplified network design/configuration.
Our products utilize ASIC and FPGA modulator and demodulator designs, and support BPSK, QPSK, OQPSK, 8-PSK, 8-QAM, 16-QAM, 64-QAM, DVB-S2, 16-APSK and 32-APSK. Depending on the modem, demodulation is accomplished by either frequency conversion down to an intermediate frequency or directly down to base band with over sampling employed. Filtering is accomplished either by switched analog filters or digitally with polyphase FIR filters in the conversion FPGA. Due to the all-digital implementation with polyphase filters, designs are readily transferred to other data rates. Our modulation and demodulation technologies operate as low as 2.4 kbps to over 238 Mbps.
RAN Optimization can significantly reduce the satellite bandwidth required for cellular backhaul. It provides the user complete control over the desired level of optimization and link quality. The pre-emptive bandwidth management maintains superior voice and service quality even under WAN congestion. Depending on the traffic profile, typical bandwidth reduction of 30-35% can be achieved with little or no impact to the voice quality. RAN optimization is available in select modems, Memotec products and the Advanced VSAT Solutions.
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WAN Optimization consists of two components, acceleration and optimization.
- Optimization – Reduces the amount of data that traverses the link by using compression and caching techniques. Provides traffic shaping on the link to allow different users and applications to get appropriate access.
- Acceleration – Gets the data to the user faster by reducing and overcoming the limitations of the underlying protocols. There is a natural synergy between acceleration and optimization. When the amount of data is reduced, it will also get there faster.
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- Medical insurance – choice of HMO / POS / HSA
- Dental insurance – choice of HMO / PPO
- Vision insurance
- Company paid life and Accidental Death and Dismemberment (AD&D) insurance
- Optional supplemental life and AD&D insurance
- Disability insurance – company paid short-term
- Optional supplemental short-term and long-term disability insurance
- Athletic club reimbursement
- 401(k) company match and automatic enrollment for all employees
- Employee stock purchase plan
- Tuition assistance
- Flexible spending account plan
- Paid vacation
- Paid personal time off
- 10 company paid holidays per year
- Sick leave
- Family leave
- Miscellaneous leave policies (military, jury duty, bereavement)
Traffic Prioritization shapes bandwidth utilization so that capacity requirements for mission-critical applications are always met. By controlling the transmission of specific applications, administrators are able to keep within bandwidth limits and to prioritize applications over satellite links.
Quality of Service (QoS) is used to classify and prioritize network applications based on business objectives to guarantee optimal application performance regardless of network conditions by assigning priority or bandwidth guarantees and limits for each application. Satellite links are subjected to limited amount of bandwidth. QoS traffic management enables network administrators to define preferential treatment for certain classes of traffic. For hub deployments, QoS provides TCP rate controls and priority levels capable of to supporting many remote sites, while, remote sites use QoS to prioritize applications and user types.
Even with proper QoS priorities in place, applications with large file transfers, such as CIFS, FTP, and backup systems can starve real-time applications such as VoIP and streaming media (e.g. video). Even if a real-time application has priority, the bulky nature of large-transfers takes too long to clear the satellite link – even when queuing and traffic shaping are enabled. The added latency that results can make a critical application such as VoIP impossible for many remote sites. To address this problem, Stampede’s FX Series reduces the size of data packets, and intelligently manages packets based on satellite link capability and application profiles.
The FX Series Traffic Shaping is a powerful feature which ensures on-time delivery of time-critical information. Through specific port assignments, priorities and policies that can be assigned at the database-level, guaranteeing Quality of Service for critical applications. The FX Series Traffic shaping feature allows different TCP ports to be assigned to individual applications, such as email and VoIP. These TCP ports are used in conjunction with Traffic Shaping hardware to provide different levels of service quality. This allows administrators to define the “Quality of Service” attributes used for traffic control based on either “Traffic Classes” or “Bandwidth Pools”.
Dynamic Data Suppression (DDS) is block level de-duplication, which is a technique for recognizing and replacing repetitive streams of payload data with signatures prior to transmission over the satellite links. DDS is not application protocol specific and can be applied to most TCP application traffic. The FX Series intelligently monitors the data stream and is able to distinguish protocol headers which change frequently from payload data which is often static. The FX Series extracts this payload data and segments it into blocks, storing each block into persistent memory known as a “byte cache”. Blocks of data are replaced with a signature for that data. This generates significant data reduction.
The FX Series provides application-aware modules for HTTP, HTTP/S, CIFS, MAPI, POP3, SMTP, and FTP that dramatically reduce costly handshakes and intelligently apply compression to lower bandwidth consumption and reduce latency.
Stampede specializes in optimizing protocols by consolidating multiple transactions into a single transaction, which eliminates round-trips, performing cache differencing on dynamically generated content, and bi-directional data compression. In addition, our patented technology (TurboStreaming) enables the transfer of previously compressed objects up to 5 times faster through intelligent multiplexing across multiple TCP sessions.
- TCP and HTTP applications have chatty protocols that put added delay in satellite networks, as do delay-sensitive applications such as VoIP and applications such as Microsoft Exchange and CIFS.
- IT managers are placing thousands of applications on their satellite links. Many of these applications are mission-critical, and compete over a limited amount of bandwidth.
Advanced Virtual Pipelining™ (AVP) is a technique developed by Stampede that provides 40% performance improvements for browser-based applications. This performance improvement is on top of the FX Series industry leading performance, and is only possible because of innovative technology for two-way application acceleration.It becomes an important and standard acceleration technique used with the FX Series family of products.
AVP is a highly optimized implementation of the patented TurboStreaming™ (multiplexed TCP sessions, patent # 7,543,072) that enables HTTP browser traffic to be intermixed across multiple “pipelines”. All browser activity is optimized, including the network-intensive polling associated with Web 2.0 and AJAX applications. A key advantage of our AVP implementation is that communication resources can be shared across multiple applications, and all HTTP requests and responses from any application (including multiple browsers) are intermixed simultaneously across multiple concurrent sessions. AVP serves as a platform for the consolidation and aggregation of all Web-based traffic from a given user. AVP logically aggregates multiple HTTP protocol streams across a few TCP sessions. Individual objects or pieces of objects can be split into any size and then multiplexed with other object data and reconstructed as needed SNSPs that deliver mixed payloads consisting of business-critical applications and data, streaming media, Voice Over Internet Protocol (VoIP) and other network-intensive traffic. The end result is improved throughput and faster response time for the end-user.
AVP enables the browser to open multiple pipelines (10s or even 100s) that communicate with the FX Series remote appliances. All of this data, from all browsers and all browser windows, is intelligently multiplexed over multiple TCP sessions (TurboStreaming) back to the head-end FX Series appliance. This fully utilizes all available bandwidth, and enables the browser to function at its full potential. This is only possible because of our advanced, industry leading two-sided acceleration technology.
The FX Series uses patented (PN# 6,012,085) “Multi-get” technology to reduce the chattiness of the HTTP protocol. In some cases, a single page retrieval will cause hundreds of HTTP Get requests to be issued by the browser.
A single page is returned to the browser that contains many embedded URLs needed for proper display of the original page. These URLs can be for additional HTML pages, image data such as pictures in the form of gifs and jpegs, java scripts and so on. The browser will first download the main page and then request the embedded URLs essentially one at a time. The latest browsers typically open several connections to retrieve these objects to overlap the retrieval process.
There are two problems with this approach. First, each item request causes a separate HTTP request/response round trip. For a first time retrieval of a page this may mean between 10 and 100 or more round trips to the Web server. More complicated pages can cause significantly more round trips. Secondly, the extra connections the browser uses can add significant load to a Web server and to the network infrastructure.
The FX Series Multi-get technology examines the first page when it is downloaded and builds a patented Multi-get request that contains an optimized “GET” for all of the necessary additional objects. The FX Series appliance parses this request and streams the objects to the remote FX Series appliance that caches them and returns them to the browser when the browser requests them. The FX Series Multi-get/Multi-verify technology determines which objects need to be retrieved freshly and which can be conditionally retrieved. All objects are retrieved in one logical request and streamed to the FX Series appliance.
The Multi-get/Multi-verify technology virtually eliminates the “chattiness” of the HTTP protocol. However, the Multi-get technology is not limited to HTML pages and is employed wherever possible; such as with JAVA Server Pages (JSPs) and Active Server Pages (ASPs) that have embedded Java Scripts. Advanced protocol optimizations drive significant improvements in bandwidth efficiencies and time savings, providing significant payload reductions and improved application delivery speeds. The FX Series specializes in optimizing the HTTP protocol by consolidating multiple transactions into a single transaction, which eliminates round-trips that add latency that can be responsible for up to 95% of the total application delay. Important protocols for satellite communications are HTTP (web mail, web surfing, enterprise web apps), POP3/ SMTP (email), HTTPS (enterprise accounts), CIFS (enterprise accounts). Stampede delivers true HTTP / HTTPS protocol optimization:
- Multi-get
- Content validation
- Intelligent cache-differencing, including dynamic content
- JPEG compression and smoothing
Intelligently caches Microsoft® Updates on the client side saving significant bandwidth attributed to “Patch Tuesday”. The FX Series caching methodology handles the rather complicated procedures employed by Microsoft and other AV vendors to request updates by requesting “partial objects”. This reduces the amount of data sent over satellite links to reduce bandwidth consumption and provide faster response times for end-users.
The FX Series Remote can dramatically curb bandwidth consumption by caching software updates published frequently by Microsoft, Symantic, Adobe, Apple and many other leading software vendors. Most Satellite service providers are aware of the bandwidth impact of “Patch Tuesday” – the day that Windows updates are distributed. The delivery of these updates is performed when software that resides on client devices downloads the new content in the background by requesting “partial content” over HTTP. The complex nature of “partial-content” HTTP requests thwarts the capabilities of most caching devices, however the FX Series Remote appliance caching engine can handle these requests. Once the content is cached by the FX Series Remote, subsequent retrievals by the updating agents that request “partial-content” will be satisfied by the FX Series Remote appliance, eliminating the need to repetitively transfer the same updates over satellite links.
The FX Series multiplexes large data objects using Stampede’s patented TurboStreaming™ (multiplexed TCP sessions, patent # 7,543,072) that enables HTTP browser traffic to be intermixed across multiple “pipelines”. All browser activity is optimized, including the network-intensive polling associated with Web 2.0 and AJAX applications. A key advantage of TurboStreaming is that communication resources can be shared across multiple applications, and all HTTP requests and responses from any application (including multiple browsers) are intermixed simultaneously across multiple concurrent sessions.
TurboStreaming serves as a platform for the consolidation and aggregation of all Web-based traffic from a given user. Multiple HTTP protocol streams are logically aggregated across a few TCP sessions. Individual objects or pieces of objects can be split into any size and then multiplexed with other object data and reconstructed as needed SNSPs that deliver mixed payloads consisting of business-critical applications and data, streaming media, Voice Over Internet Protocol (VoIP) and other network-intensive traffic. The end result is improved throughput and faster response time for the end-user.
TurboStreaming enables the browser to open multiple pipelines (10s or even 100s) that communicate with the FX Series remote appliances. All of this data, from all browsers and all browser windows, is intelligently multiplexed over multiple TCP sessions back to the head-end FX Series appliance. This fully utilizes all available bandwidth, and enables the browser to function at its full potential. This is only possible because of advanced, industry leading two-sided acceleration technology.
Caching brings information closer to the end-user by storing recently accessed data in local memory or on hard disk, reducing the time it takes to bring back needed information, making the user experience more positive and action oriented. While today’s browsers maintain their own cache, they tend to be overly conservative. This means they will err on the side of requesting a new piece of data or object, usually when it really hasn’t been changed. This not only impacts response time to the end-user, but also saturates bandwidth with unnecessary data transmission. Cache Differencing takes the concept one step further and maintains identical copies of the browser’s cache at the local device and on the FX Series appliance. The FX Series then uses intelligent differencing technology to understand what data has actually changed, and then transfers only the changed data. The local device functions normally, but with less data being transferred, you realize improved utilization of the satellite network, and increased end-user productivity.
Traditionally, pages can be marked as cacheable and will have expiration dates. When they expire they must be retrieved from the original server, resulting in additional traffic and data being transmitted across the satellite network. Within a two-sided environment, the FX Series remote appliance caches all pages returned to the browser (even pages that are marked as non-cacheable) and performs validation when needed to ensure that no stale data is returned to the browser. When the browser asks for a page or an item that has expired or been marked as non-cacheable, the FX Series remote appliance sends a validation request to the FX Series appliance at the head-end. If the FX Series appliance is aware of the last page the client cache contains and can compute differences in the page, it sends just the differences to an expired page or non-cached page. If the differences are too big, or if the FX Series appliance no longer has retained the last version that the client has, then the entire page is returned and subsequently cached for future possible differencing. The client in turn reconstructs the requested page, caches it, and returns it to the browser. Checksums are calculated by the FX Series appliance at the head-end and verified at the FX Series remote appliance so that pages will never be delivered incorrectly. While this technique adds value on expired pages, it is extremely effective for dynamic page generation.
An important aspect of Stampede’s Cache Differencing is the ability to perform differencing not only on HTML GET requests but also on POST requests. This is significant because a) responses to posts are always marked non-cacheable, and b) most applications that are based on SOAP and XML (including most AJAX applications) issue SOAP requests via the HTML POST command.
Advanced protocol optimizations drive significant improvements in bandwidth efficiencies and time savings (reducing payload and latency). WAN optimization and application acceleration technologies are deployed to improve satellite network performance and increase the amount of applications and users that can be delivered over the satellite link. The FX Series manages all TCP sessions, and handles the establishing and tearing down of TCP connections locally (at LAN speeds) to avoid satellite network congestion problems. This helps to increase link utilization and improve the user experience. TCP termination offloads the responsibility from servers having to handle the overhead imposed by the volume of TCP connections from web applications.
Additionally, application level multiplexed TCP streams take advantage of all other TCP or protocol optimization done at the link level, and application-level handshakes are eliminated by consolidating transaction requests.
Benefits include:
- Increases server capacity
- Reduces the amount of traffic sent over satellite links
- Keeps the satellite links maximized for optimum utilization
- Dramatically reduces transaction TCP turns (requests and responses) that bottleneck satellite links
For customers who use Microsoft’s Internet Explorer browser, the FX Series can reduce round trips during Internet sessions by marking the HTTP objects to allow IE to extend the time that the objects are stored within the browser cache without the content becoming stale.
Caching brings information closer to the end-user by storing recently accessed data in local memory or on hard disk, reducing the time it takes to bring back needed information, making the user experience more positive and action oriented. While today’s browsers maintain their own cache, they tend to be overly conservative. This means they will error on the side of requesting a new piece of data or object, usually when it really hasn’t been changed. This not only impacts response time to the end-user, but also saturates bandwidth with unnecessary data transmissions.
The FX Series uses caching to maintain copies of routinely accessed data to eliminate unnecessary requests to Web and application servers, and from going over limited satellite links. By keeping local copies of frequently requested content, the FX Series allows organizations to significantly reduce their upstream bandwidth usage and cost, while improving performance. The FX Series acts as an intermediary from end-users requesting content (such as a file, web page, or other resource) from servers. Some of the key benefits include:
- Reducing bandwidth consumption
- Keeping servers behind the FX Series anonymous for security purposes
- Delivering fast access to content
Image Reduction and Smoothing reduces the amount of data required to represent an image without significantly altering the visual perception of the image. This is accomplished in two ways. Smoothing reduces the high frequency components or the sharpness of an image. A moderate amount of smoothing can significantly reduce the amount of data. The quality factor of a JPEG image relates to the precision of the samples. Sample precision can be reduced without visible detection.
The goal of the JPEG quality and smoothing values is to reduce the amount of data while maintaining a usable image. Depending on the JPEG, the compression is often in the range 9:1. A number between 1 and 100 specifies the tradeoff between size of the jpeg data and quality of the original image. A higher number will retain a higher quality but will not conserve as much bandwidth. If no value is specified then the FX Series value is inherited from a higher level policy; a default value of 25 is used if no higher level policy is defined. Images that have been transformed are typically not significantly changed by running through the algorithm again. What this means is that if an image has been compressed with particular smoothing and quality factor, if the same factors are used again, the image is not significantly changed.
GZIP compression is handled on-the-fly from the servers to the clients. This reduces bandwidth consumption and improves application delivery and client response time. The FX Series uses GZIP compression to reduce the payload size to deliver more data across the satellite link, enabling more applications to be delivered and the ability to support more users. GZIP compression removes non-essential information from data being moved from one location to another, and then reassembles the data to its original form after the transfer is complete.
Squeezing the data reduces network traffic and accelerates the delivery of time-sensitive information. GZIP compression uses standard techniques to compress data sent to browsers. While compression exists in many forms throughout Web deployments, the FX Series is able to more effectively apply compression resulting in better compression ratios. The most common use of compression in Web environments is accomplished by enabling GZIP functionality at the Web server. This is useful for reducing the text portions of pages, but GZIP is not normally used for attachment compression or for inbound compression from the browser. In addition, GZIP cannot be used to compress HTTP headers or image data.
Stampede utilizes various compression techniques to reduce the amount of data that must be sent across the network. In a single-sided mode, the FX Series appliance utilizes GZIP to compress information that can be processed by standard browsers. This is useful for reducing the text portions of pages, but GZIP is not normally used for attachment compression or for inbound compression from the browser. In addition, GZIP cannot be used to compress HTTP headers, cookies or image data. In two-sided deployment, the FX Series bi-directional compression provides compression for:
- All HTTP Headers
- Application Cookies
- All Text and Data Objects
- JPEG files with Image Reduction, yielding very acceptable quality
- All attachments and file uploads and downloads
Bandwidth pooling is used by satellite network service providers (SNSPs) to enforce a rate limit on traffic coming from their head-end out to different subnets. It allows SNSPs to define a pool, and associate a maximum bit-rate to that pool. With a defined pool, subnets are then identified as part of the pool. The FX Series enforces traffic limits based on the network administrator-defined throttle of the bandwidth pool so that the data going through the pool does not exceed the specified parameters.
A bandwidth pool consists of a record that includes a name, rate and subnet that belong to a specific pool. A SNSP can associate a carrier (or beam) to a bandwidth pool. In this case, a bandwidth pool corresponds to a specific satellite traffic beam. For network managers, the problem arises when assigning separate subnets over a single beam that may have any number of associated subnets.
The FX Series allows the administrator to restrict the data flow over a beam based on how they defined the subnets to their customers. This enables the administrator to apply QoS to the subnets, and have greater control over the re-transmission requirements for each subnet. This also alleviates the network architect or engineer from having to change each individual subnet, rather than having to individually shape each subnet so that all the subnets equal the total amount of bandwidth available for a single beam. The FX Series greatly simplifies this process by allowing network administrators to easily input the maximum rate for a particular beam (or carrier), and the subnets, and ensures that the traffic load will not exceed the rate. This also provides greater bandwidth flexibility by not enforcing an artificial rate limit on a per-subnet basis.
The FX Series takes traffic control to a new level. Stampede developed an easy-to-use Web GUI around the complex rate shaping technology that is built into the FX Series. With the Web GUI, network personnel are able to easily configure bandwidth pools. The FX Series Web GUI allows administrators to define a bandwidth pool and give it a rate, then add separate subnets to that pool. The FX Series appliance then dynamically throttles the traffic according to the specifications of the pool.
Connection management removes the burden of establishing and terminating TCP connections from the web servers, allowing the server to handle more traffic. Stampede manages network connections in several ways to optimize the flow of data and reduce the impact on the network, application servers and end-user devices. The FX Series appliance maintains a consistent pool of connections between itself and the servers. The servers are then offloaded from managing the connections, and are isolated from inadvertent session disconnects.
With Stampede’s FX Series Remote appliances working with the FX Series head-end appliance, a persistent connection between the client and server is always maintained, even when the browser may close and reopen a session. These sessions are also multiplexed across multiple connections, improving throughput and response time. This persistent connection is extremely important for AJAX and Web 2.0 applications which constantly open and close sessions as they poll and access various Web services. Stampede eliminates this potentially network intrusive overhead.
IP Source Preservation is a technology that is used to support security policies that require a specific source IP address, or range of IP addresses. It is also used to prevent the FX Series appliance from being blacklisted.
For example, in the event where a situation is deemed inappropriate, such as a SPAM event, the sending device Source IP address will be blacklisted. To avoid this problem, the FX Series uses the end-user’s Source IP address when making a request to a Web or application server. The FX Series configuration method makes implementing IP Source Preservation easy within a WCCP or inline environment. The FX Series is usually configured to use the IP address of the client when making requests to content servers, whereas, other acceleration devices make requests to Web servers using their own IP address. IP addressing problems can occur when, for example, an end-user is involved with illegal online activity and the IP address of the acceleration device is recorded in the Web server’s logs. If the IP address of the acceleration device is used to make the client request to the server, it will likely be placed on a blacklist, and therefore cause considerable network problems. By spoofing the IP address of the client, the FX Series is able to avoid this problem.
The Web Cache Communications Protocol (WCCP) allows satellite network service providers to transparently inject acceleration into their satellite network infrastructure by redirecting traffic flows in real-time to network devices such as the FX Series. WCCP has built-in load balancing, scaling, fault tolerance, and service-assurance (failsafe) mechanisms to ensure network devices can scale and have high-availability. For fault tolerance, if one of the FX Series appliances incurs a hardware failure, the WCCP-enabled router will stop sending traffic to that device and redirect traffic to the other FX Series appliances with zero down-time.
Load balancing via WCCP intelligently distributes the TCP and HTTP workload across multiple FX Series appliances. For flexible scalability, service providers can simply add an FX Series appliance to the cluster, and WCCP will split the traffic load among all the FX Series appliances. Up to thirty-two FX Series appliances can be set up within a cluster and dynamically load balanced.
WCCP enables network service providers to implement the FX Series into their network with greater deployment flexibility, without requiring the FX Series to be physically in-line. The FX Series can be deployed “virtually” in-line, hence, not all traffic is required to pass through the FX Series appliance. The network administrator programs the router to redirect traffic to the FX Service appliance in-bound and out-bound based on the router policies. This allows the administrators to make changes to their network environment by simply changing the router policies.
Stampede’s FX Series (running WCCP) localizes content, and responds to content requests in order to reduce the amount of data going over the WAN. This improves application delivery response times, and allows the WAN link to support more traffic. Using WCCP, traffic is transparently redirected to the FX series appliance for TCP and HTTP acceleration, compression, caching and other optimization services.
With WCCP configured, the router redirects traffic to the FX Series to perform the application acceleration and WAN optimization functions. When an end-user makes a request, the router intercepts the request, and redirects the request to the FX Series inside a generic routing encapsulation (GRE) frame to prevent any modifications to the original packet. The FX Series with WCCP can be used to transparently route traffic, so that you don’t have to make changes to Web browsers, and configure the FX Series as a proxy server to offload servers, accelerate application delivery and optimize the network.
Further demonstrating our technology leadership and innovation, we hold a number of patents.
Our patent-pending Automatic Carrier-in-Carrier Power Control (ACPC) mechanism solves the power control optimization problem in a very general way for CnC links. It provides a unique opportunity for modems on both sides of a CnC link to automatically measure and compensate for rain loss while maintaining a fixed PEB on the satellite during all conditions. In addition to automatically compensating for rain loss, ACPC also enables CnC modems to share link margin between modems (i.e. a modem experiencing clear sky conditions can effectively give excess link margin to a distant end modem experiencing rain conditions, thereby further enhancing overall availability). This feature is implemented using values measured by the modems and general rain model knowledge (i.e. a system level implementation is not required). The net effect of ACPC technology is a significant increase in effective link margin and availability for CnC links while ensuring no increase in the PEB at the satellite.
Adaptive Coding and Modulation is a statistical, non-static advantage that enables dynamic changes in user throughput. Benefits and value vary over time and are not guaranteed, but are predictable. ACM technology converts link margin to an increase in the data throughput of satellite links. When utilizing ACM operation in our modems and Advanced VSAT Solutions, link margin can be converted into increased throughput of satellite links.
AutoEQ supports amplitude and group delay equalization over the satellite system. When installed, it offers the ability to compensate the overall system group delay and amplitude flatness by pre-correcting the uplink carrier. This eliminates the need for external group delay/amplitude equalizers and makes possible equalization at L-Band.
AUPC is a feature whereby a local modem is permitted to adjust its own output power level in order to attempt to maintain the Eb/No at the remote modem. AUPC relies upon EDMAC for its operation. The remote modem constantly sends back information about the demodulator Eb/No using reserved bytes in the overhead structure. The local modem then compares this value of Eb/No with a pre-defined target value. If the Remote Eb/No is below the target, the local modem increases its output power, creating a closed-loop feedback system over the satellite link. A particularly attractive benefit of this feature is that whenever framed operation is selected, the remote demodulator’s Eb/No can be viewed from the front panel display of the local modem.
Satellite interference has a significant financial impact on both satellite operators and end users. We developed the MetaCarrier technology to address this severe, industry-wide challenge. The MetaCarrier technology embeds and detects a small message and unique ID within a video or data satellite carrier. This embedded message and ID significantly reduce the time to identify and clear interference sources. The MetaCarrier is embedded using spread spectrum techniques within the carrier itself without adding appreciable noise or power to the host carrier. The robust spread spectrum signal enables the host carrier to be identified even when the host carrier is well below another carrier or near the noise floor itself.
Our frequency converters utilize the patented “Daisy Chain” integrated switching technology. The Daisy Chain design removes the relays associated with a centralized protection switch tray and distributes them across the individual converters. We were awarded patent 5,666,646 on this distributed protection switch topology.
Our revolutionary and award-winning technology allows full duplex satellite links to transmit concurrently in the same segment of transponder bandwidth. When combined with the advanced forward error correction and modulation techniques in our modems, DoubleTalk Carrier-in-Carrier delivers improved satellite transponder utilization and unprecedented operating expense savings.
We added a new approach to continuously optimize satellite communication efficiency – Dynamic Predistortion (DPD) on the CDM-760. Working in tandem with DPD, a new crest factor reduction (CFR) technique is dynamically applied as well to further enhance performance. These innovative technologies, collectively labeled and referred to as DPD, create high signal integrity while operating the satellite transponder in the higher efficiency nonlinear region. They provide a significant increase in link margin, by as much as 2 dB, and/or in spectral efficiency, by as much as 6%.
Our Vipersat Management System (VMS) automates bandwidth utilization while optimizing space segment efficiency. The software allows intelligent management of satellite networks through system configuration and alarm management of the network. VMS is the engine that provides dynamic SCPC (dSCPC) bandwidth management of space segment.
Our EDMAC capability permits the users to access the M&C features of distant-end modems in a satellite link. This is accomplished by adding extra information to the user data in a manner that is completely transparent to the users.
Forward Error Correction is a powerful technique for improving the performance of error-prone channels found in communication systems. The performance of FECs can be evaluated based on their distance from Shannon limit. We offer traditional and advanced methods of forward error correction to improve performance of error-prone channels. Examples of our modems’ advanced FECs are:
- VersaFEC-2
- VersaFEC®
- Low-Density Parity-Check Codes (LDPCs)
- DVB-S, DVB-DSNG and DVB-S2
- 2nd Generation Turbo Product Codes (TPC)
Our modems are extremely flexible and powerful, and incorporate a large number of optional features that can be purchased at the initial order or while in the field. The FAST technology facilitates on-location upgrade of the operating feature set without removing a modem from the setup. With FAST technology, users have maximum flexibility for enabling functions as they are required. FAST allows a user to order a modem precisely tailored for the initial application. When service requirements change, the operator can upgrade the topology of the modem to meet those requirements within minutes. FAST permits the purchase and installation of options through special authorization codes loaded into the unit either via the front panel keypad or entered remotely via the remote port located on the modem rear panel. This accelerated upgrade can be accomplished because of FAST’s extensive use of the programmable logic devices incorporated into our products.
There are some applications where it becomes necessary, at the distant end of a satellite link, to provide a high-stability G.703 timing reference for timing equipment connected to the modem. For example, in cellular backhaul applications, the BTS equipment may require such a reference even though the satellite link itself may be operating at a data rate other than 1.544 Mbps or 2.048 Mbps. This is sometimes accomplished by adding a specialized GPS receiver at the distant end, which then provides the G.703 synchronizing signal. However, with the G.703 clock extension mode this may become unnecessary, as our modems with this feature – operating at either end of the link, where the local modem has access to a high-stability G.703 signal – can provide an almost perfect copy of this signal at the distant end. The presence of Doppler shift on the link is the only factor affecting the overall accuracy. If Doppler shift were not present, the copy of the clock would be perfect.
H-DNA is an evolutionary and dynamic network access technology designed for the Heights Networking Platform’s return links. It is fast, flexible and uncompromising, delivering unprecedented benefits to users and service providers alike.
Our advanced functionality allows for efficient IP networking and transport over satellite, and is available for select modems and the Advanced VSAT Series. Available options include header compression, payload compression, ultra low overhead streamline encapsulation and quality of service. When utilizing the advanced IP functionality, real-time traffic and other low priority traffic can seamlessly co-exist on the same link without impacting the voice quality or delivery of mission critical data. The functions provide high bandwidth efficiency, information security and simplified network design/configuration.
Our products utilize ASIC and FPGA modulator and demodulator designs, and support BPSK, QPSK, OQPSK, 8-PSK, 8-QAM, 16-QAM, 64-QAM, DVB-S2, 16-APSK and 32-APSK. Depending on the modem, demodulation is accomplished by either frequency conversion down to an intermediate frequency or directly down to base band with over sampling employed. Filtering is accomplished either by switched analog filters or digitally with polyphase FIR filters in the conversion FPGA. Due to the all-digital implementation with polyphase filters, designs are readily transferred to other data rates. Our modulation and demodulation technologies operate as low as 2.4 kbps to over 238 Mbps.
RAN Optimization can significantly reduce the satellite bandwidth required for cellular backhaul. It provides the user complete control over the desired level of optimization and link quality. The pre-emptive bandwidth management maintains superior voice and service quality even under WAN congestion. Depending on the traffic profile, typical bandwidth reduction of 30-35% can be achieved with little or no impact to the voice quality. RAN optimization is available in select modems, Memotec products and the Advanced VSAT Solutions.
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WAN Optimization consists of two components, acceleration and optimization.
- Optimization – Reduces the amount of data that traverses the link by using compression and caching techniques. Provides traffic shaping on the link to allow different users and applications to get appropriate access.
- Acceleration – Gets the data to the user faster by reducing and overcoming the limitations of the underlying protocols. There is a natural synergy between acceleration and optimization. When the amount of data is reduced, it will also get there faster.