In addition, with awareness of URLs, the switch can recognize GIFs, JPEGs and other cachable items and automatically direct this traffic to the cache. Navisite uses ArrowPoint s content aware switches to help prevent dropped shopping carts. Dropped shopping carts are a big problem for customers at very large ISPs that use proxy server portals to the Internet. For example, all Internet traffic from AOL subscribers originates from an IP number representing one of these proxy servers. But with content awareness, the ArrowPoint CS-800 switch eliminates this problem with the ability to load balance either with sticky cookies or by using a sticky subnet mask to maintain server affinity, even though its IP address might change.
Sticky cookies are a way to identify the user and assure that the user is handled without loss.
Sticky subnets, on the other hand, provide a solution that does not require a code change as it is fully handled in the switch. For example, AOL has a number of subnets, but a unique subnet for each backbone. A user may be switched from one of AOL s proxy servers to another, but AOL will not change the backbone, so all the proxy servers from that user are on the same AOL subnet. The ArrowPoint switch directs traffic from a given subnet to the same server, thus avoiding a dropped shopping cart. In addition, content awareness provides increased protection against Denial of Service attacks.