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Web OS 10.0 Application Guide
Content Intelligent Web Cache Redirection
Web OS allows you to redirect Web cache requests based on different HTTP header information,
such as "Host:" header or "User-Agent" for browser-smart load balancing. For more information
on layer 4 Web cache redirection, see
The No Cache/Cache Control for Web Cache Redirection (WCR) feature in Web OS allows
you to off load the processing of non-cacheable content from cache servers by sending only
appropriate requests to the cache server farm. When a Cache-Control header is present in a
HTTP 1.1 request, it indicates a client's special request with respect to caching, such as to guar-
antee up-to-date data from the origin server. If this feature (Cache-Control: no cache directive)
is enabled, HTTP 1.1 GET requests are forwarded directly to the origin servers.
N
OTE
The HTTP 1.0 Pragma: no-cache header is equivalent to the HTTP 1.1 Cache-Con-
trol header. By enabling the Pragma: no-cache header, requests are forwarded to the ori-
gin server.
N
OTE
switch.
This section discusses the following types of Web cache redirection:
n
"URL-Based Web Cache Redirection" on page 395
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"HTTP Header-Based Web Cache Redirection" on page 403
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"Browser-Based Web Cache Redirection" on page 405
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"URL Hashing for Web Cache Redirection" on page 406
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"Layer 7 RTSP Streaming Cache Redirection" on page 409
n
394
Chapter 15: Content Intelligent Switching
–
The term origin server refers to the server originally specified in the request.
–
For WCR, at any given time one HTTP header is supported globally for the entire
Chapter 8, "Application
Redirection."
212777-A, February 2002
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