WAN Optimization - WAN Optimization Techniques

WAN Optimization Techniques

• Deduplication – Eliminates the transfer of redundant data across the WAN by sending references instead of the actual data. By working at the byte level, benefits are achieved across IP applications.
• Compression – Relies on data patterns that can be represented more efficiently. Essentially compression techniques similar to ZIP, RAR, ARJ etc. are applied on-the-fly to data passing through hardware (or virtual machine) based WAN acceleration appliances.

• Latency optimization – Can include TCP refinements such as window-size scaling, selective Acknowledgements, Layer 3 congestion control algorithms, and even co-location strategies in which the application is placed in near proximity to the endpoint to reduce latency. In some implementations, the local WAN optimizer will answer the requests of the client locally instead of forwarding the request to the remote server in order to leverage write-behind and read-ahead mechanisms to reduce WAN latency.

• Caching/proxy – Staging data in local caches; Relies on human behavior, accessing the same data over and over.

• Forward error correction – mitigates packet loss by adding an additional loss-recovery packet for every “N” packets that are sent, and this would reduce the need for retransmissions in error-prone and congested WAN links.

• Protocol spoofing – Bundles multiple requests from chatty applications into one. May also include stream-lining protocols such as CIFS.

• Traffic shaping – Controls data flow for specific applications. Giving flexibility to network operators/network admins to decide which applications take precedence over the WAN. A common use case of traffic shaping would be to prevent one protocol or application from hogging or flooding a link over other protocols deemed more important by the business/administrator. Some WAN acceleration devices are able to traffic shape with granularity far beyond traditional network devices. Such as shaping traffic on a per user AND per application basis simultaneously.

• Equalizing – Makes assumptions on what needs immediate priority based on the data usage. Usage examples for equalizing may include wide open unregulated Internet connections and clogged VPN tunnels.

• Connection limits – Prevents access gridlock in routers and access points due to denial of service or peer to peer. Best suited for wide open Internet access links, can also be used on WAN links.

• Simple rate limits – Prevents one user from getting more than a fixed amount of data. Best suited as a stop gap first effort for remediating a congested Internet connection or WAN link.