Radware Alteon, Инструкция по применению

Страница: 466 / 842

Alteon Application Switch Operating System Application Guide
Application Redirection
466
Document ID: RDWR-ALOS-V2900_AG1302
Content-Intelligent Cache Redirection
Alteon lets you redirect cache requests based on different Layer 7 content for HTTP header
information such as "Host:" header or "User-Agent" for browser-smart load balancing.
The No Cache/Cache-Control for cache redirection lets you offload 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 guarantee 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.
Note: Origin server refers to the server originally specified in the request.
The HTTP 1.0 Pragma: no-cache header is equivalent to the HTTP 1.1 Cache-Control header. By
enabling the Pragma: no-cache header, requests are forwarded to the origin server.
For cache redirection, at any given time one HTTP header is supported globally on Alteon. This
section discusses the following types of cache redirection:
• URL-Based Cache Redirection, page 466
• HTTP Header-Based Cache Redirection, page 472
• Browser-Based Cache Redirection, page 474
• URL Hashing for Cache Redirection, page 475
• RTSP Streaming Cache Redirection, page 477
URL-Based Cache Redirection
URL parsing for cache redirection operates in a manner similar to URL-based server load balancing,
except that in cache redirection a virtual server is the target of all IP/HTTP requests.
By separating static and dynamic content requests via URL parsing, Alteon enables you to send
requests with specific URLs or URL strings to designated cache servers. The URL-based cache
redirection option lets you offload overhead processing from the cache servers by only sending
appropriate requests to the cache server farm.
Note: Both HTTP 1.0 and HTTP 1.1 requests are supported.
Each request is examined and handled as described below:
• If the request is a non-GET request such as HEAD, POST, PUT, or HTTP with cookies, it is not sent
to the cache.
• If the request is an ASP or CGI request or a dynamically generated page, it is not sent to the
cache.
• If the request contains a cookie, it can optionally bypass the cache.
Examples of matching string expressions are:
>> SLB port 5# /cfg/slb/port 6
(Select SLB Port 6)
>> SLB port 6# add 1
(Add the filter to Port 6)
>> SLB port 6# apply
(Apply configuration changes)
>> SLB port 6# save
(Save configuration changes)