Web OS 10.0 Application GuideChapter 15: Content Intelligent Switching n 387212777-A, February 2002URL Hashing for Server Load BalancingBy default, hashing algorithms use the IP source address and/or IP destination address(depending on the application area) to determine content location. The default hashing algo-rithm for SLB is the IP source address. By enabling URL hashing, requests going to the samepage of an origin server are redirected to the same real server or cache server.Virtual Server Load Balancing of Nontransparent CachesYou can deploy a cluster of non-transparent proxy caches and use the virtual server to load bal-ance requests to the cache servers. The client’s browser is configured to send Web requests to anontransparent cache (the IP address of the configured virtual server).If hash is selected as the load-balancing algorithm, the switch hashes the source IP address toselect the server for SLB. Under this condition, the switch may not send Web requests for thesame origin server to the same proxy cache server. For example, requests made from a client to“http://www.nortelnetworks.com/products” from different clients may get sent to differentcaches.Figure 15-3 Balancing Nontransparent CachesConfiguring URL HashingYou can direct the same URL request to the same cache or proxy server by using a virtualserver IP address to load balance proxy requests. By configuring hash or minmisses as themetric, the switch uses the number of bytes in the URI to calculate the hash key.If the host field exists and the switch is configured to look into the Host: header, the switchuses the Host: header field to calculate the hash key.Client's browser is configuredto send Web requests to theorigin server via the virtual serverVirtual Server IP Address:205.178.13.243Non-TransparentCache Farm$$ $
