Nortel Networks WEB OS 212777 - Manual (Page 395)

Web OS 10.0 Application Guide
Chapter 15: Content Intelligent Switching n 395
212777-A, February 2002
URL-Based Web Cache Redirection
URL parsing for Web Cache Redirection operates in a manner similar to URL-based server
load balancing except that in WCR a virtual server on the switch is the target of all IP/HTTP
requests
. For information on URL-based server load balancing , see “URL-Based Server Load
Balancing” on page 375 .
By separating static and dynamic content requests via URL parsing, Web OS enables you to
send requests with specific URLs or URL strings to designated cache servers. The URL-based
WCR option allows you to off load overhead processing from the cache servers by only send-
ing appropriate requests to the cache server farm.
N OTE – Both HTTP 1.0 and HTTP 1.1 requests are supported.
Each request is examined and handled as described below:
n
If the request is a non-GET request such as HEAD, POST, PUT, or HTTP with cookies, it
is not sent to the cache.
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If the request is an ASP or CGI request or a dynamically generated page, it is not sent to
the cache.
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If the request contains a Cookie, it can optionally bypass the cache.
You can configure up to 32 URL expressions, each 8 bytes long, for noncacheable content
types. You can use up to 128 strings, comprising of 40 bytes each for URL string matching on
each switch. As each URL Web request is examined, noncacheable items are forwarded to the
origin server while requests with matching strings are redirected to the appropriate cache
server.
Examples of matching string expressions are:
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/product
Any URL that starts with “/product,” including any information in the “/product” direc-
tory
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product
Any URL that has the string “product”