Chapter 17: Web Hosting Configuration Guide

Web Caching

Web caching provides a way to store frequently accessed Web objects on a cache of local servers. Each HTTP request is transparently redirected by the SSR to a configured cache server. When a user first accesses a Web object, that object is stored on a cache server. Each subsequent request for the object uses this cached object. Web caching allows multiple users to access Web objects stored on local servers with a much faster response time than accessing the same objects over a WAN connection. This can also result in substantial cost savings by reducing the WAN bandwidth usage.

Note: The SSR itself does not act as cache for web objects. It redirects HTTP requests to local servers on which the web objects are cached. One or more local servers are needed to work as cache servers with the SSR’s web caching function.

Configuring Web Caching

The following are the steps in configuring Web caching on the SSR:

1.Create the cache group (a list of cache servers) to cache Web objects.

2.Specify the hosts whose HTTP requests will be redirected to the cache servers. This step is optional; if you do not explicitly define these hosts, then all HTTP requests are redirected.

3.Apply the caching policy to an outbound interface to redirect HTTP traffic on that interface to the cache servers.

Creating the Cache Group

You can specify either a range of contiguous IP addresses or a list of up to four IP addresses to define the servers when the cache group is created. If you specify multiple servers, load balancing is based on the destination address of the request. If any cache server fails, traffic is redirected to the other active servers.

To create the cache group, enter the following command in Configure mode:

Create the cache group.

web-cache <cache-name>create server-list <server-list-name>range <ipaddr- range>list <ipaddr-list>

Note: If a range of IP addresses is specified, the range must be contiguous and contain no more than 256 IP addresses.

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Cabletron Systems 9032578-05 manual Configuring Web Caching, Creating the Cache Group