In Part I and Part II of this series, we examined some WAN optimization techniques. We shall be covering a few more in this article. In this Part III article of the series, we shall conclude with a quick look at the benefits that can be derived by Cloud backup customers from WAN optimization.

Continuing our discussion from where we left off….

Caching: A cache is a temporary storage mechanism for accelerating data access. The cache may be located on a web server or on a local machine. Documents which are frequently accessed by users are often stored in a high speed memory or cache for ease of recovery. This drastically reduces the time to respond, enables scaling, and reduces the load on databases, file servers, and other storage sources.

Forward Error Correction: This technique is also known as channel coding and is used to correct errors in data transmission.  Messages are encoded redundantly to avoid errors or packet losses and consequent retransmissions of data. Cloud backup services use forward error correction with block codes or fixed sized blocks or packets as against Convolutional codes that work on bit streams of arbitrary length. This type of WAN optimization is especially useful where the WAN is congested.

Protocol Spoofing: This technique is used when existing protocol is inadequate. For instance, a TCP connection will have performance limitations of window size when linked with high bandwidth x delay product or long-delay links when connected over a GEO satellite.  The spoofing algorithm terminates the TCP protocol locally and translates it to protocols that can handle long delays over the satellite link.

Traffic Shaping: This technique is used with specific applications.  Administrators can decide which applications will take precedence on a network or preventing an application from hogging the available bandwidth. Traffic shaping is possible at granular levels. For instance, traffic shaping can be managed at per user and/or per application basis. This provides visibility and control in to network usage.

Equalizing: This technique is another prioritization technique. The priorities are determined on the basis of usage. The algorithms may be used for load balancing and task scheduling in Cloud computing.

Connection Limits: This technique is used where Internet access links are open in WAN links to prevent gridlocks in routers and access points resulting from denial of service or peer to peer access.

Simple Rate Limits: This technique ensures that every user on the network gets a fixed amount of bandwidth. This technique is especially useful where there are a large number of users and there is a likely hood of bandwidth congestion.

This article is Part III in a four part series on WAN Optimization.