Nortel Networks 212777 URL Hashing for Web Cache Redirection

Web OS 10.0 Application Guide
406 Chapter 15: Content Intelligent Switching 212777-A, February 2002
7. Add the defined string IDs to configure the real server(s) to handle the appropriate load
balance string(s).
where ID is the identification number of the defined string.
NOTE – If you don’t add a defined string (or add the ID 1), the server will handle any request.
URL Hashing for Web Cache Redirection
By default, hashing algorithms use the source IP address and/or destination IP address
(depending on the application area) to determine content location. For example, firewall load
balancing uses both source and destination I P a ddresses, WCR uses only the destination IP
address, and SLB uses only the source IP address.
Hashing is based on the URL, including the HTTP Host header (if present), up to a maximum
of 255 bytes. You can optimize “cache hits” by using the hashing algorithm to redirect client
requests going to the same page of an origin server to a specific cache server.
For example the switch could use the string “nortelnetworks.com/products/180/” for hashing
the following request:
GET http://products/180 / HTTP/1.0
HOST:www.nortelnetworks.com
To configure the switch for WCR based on a hash key, use the following procedure:
1. Configure basic SLB.
Before you can configure header-based cache redirection, ensure that the switch has already
been configured for basic SLB (see “Server Load Balancing” on page 117) with the following
tasks:
nAssign an IP address to each of the real servers in the server pool.
nDefine an IP interface on the switch.
nDefine each real server.
nAssign servers to real server groups.
nDefine virtual servers and services.
nConfigure the load-balancing algorithm to hash or minmiss.
>> # /cfg/slb/real 2/layer7/addlb <ID>