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Silver Peak employs advanced payload and header compression to maximize WAN bandwidth. “Payload” compression uses algorithms to identify relatively short byte sequences that are repeated frequently over time. These sequences are then replaced with shorter segments of code to reduce the size of transmitted data. “Header” compression can provide additional bandwidth gains by reducing packet header information using specialized compression algorithms.
Payload Compression
All Silver Peak NX appliances support advanced cross-flow payload compression techniques based on Lempel-Ziv algorithms (LZ). These are lossless techniques suitable for compression of real-time flows.
Payload compression typically yields a 2x to 4x compression ratio. This is separate from (and can be in addition to) the gains from Network Memory's data reduction techniques. The results of payload compression are typically most evident on the “first” or “cold” pass of data, with Network Memory providing significantly greater performance improvements on subsequent passes.
Header Compression
Silver Peak performs standard IP, TCP, UDP, and RTP header compression. This reduces the overhead inherent to flows of small packets, as is the case with VoIP, telnet, Citrix and some SQL applications, such as Oracle Forms. Header compression is often used in conjunction with packet coalescing, a technique employed by Silver Peak to consolidate multiple packets destined to the same location into a single packet.
Silver Peak Advantages
While compression techniques are fairly well established, Silver Peak distinguishes itself from other WAN acceleration solutions by offering the following capabilities:
- Crossflow compression: The Silver Peak solution is unique in its ability to apply compression techniques across various flows of traffic, a concept called “crossflow compression”. This enables a single dictionary to be shared across multiple flows, which leads to better efficiency and better performance.
- Multiprotocol support. Silver Peak NX appliances can compress both TCP and UDP traffic, providing a significant advantage over TCP-only solutions. Voice over IP (VoIP), for example, can significantly benefit from UDP header compression when used in conjunction with other techniques, such as packet coalescing.
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