In a typical deployment, different clients ask web servers for the same content repeatedly. To relieve the origin web server of processing each request, a NetScaler appliance with cache redirection enabled can serve this content from a cache server instead of from the origin server.
The NetScaler appliance analyzes incoming requests, sends requests for cacheable data to cache servers, and sends non-cacheable requests and dynamic HTTP requests to origin servers.
Cache redirection is a policy-based feature. By default, requests that match a policy are sent to the origin server, and all other requests are sent to a cache server. For testing or maintenance, you might want to skip policy evaluation and direct all requests to the cache or to the origin server.
You can combine content switching with cache redirection to cache selective content and serve content from specific cache servers for specific types of requested content.
A NetScaler appliance configured for cache redirection can be deployed at the edge of a network, in front of the origin server, or anywhere along the network backbone. In an edge deployment, commonly used by Internet Service Providers (ISPs), cable companies, content delivery distribution networks, and enterprise networks, the NetScaler appliance resides directly in front of the clients. In a server-side deployment, the NetScaler appliance is closer to the origin servers.
Cache redirection is used most commonly with the HTTP service type, but it also supports the secure HTTPS protocol.