How an ICP

hit can be a miss

If the appliance receives a hit message from an ICP peer, then it sends the HTTP request to that peer. It might turn out to be an actual miss, because the original HTTP request contains header information that is not communicated by the ICP query. For example, the hit might not be the requested alternate. If an ICP hit turns out to be a miss, the appliance forwards the request to either its HTTP parent caches or to the origin server.

For information on now to enable and configure ICP options using the Manager UI, see the ICP section of the Configure: Routing page (see Setting ICP options‚ on page 41). For information on how to configure ICP options using the command-line interface see Configuring and maintaining ICP peers‚ on page 84.

NNTP cache hierarchies

Using an Intel NetStructure Cache Appliance as parent to another group of appliances can reduce load on a parent news server and take advantage of the large number of concurrent connections that server supports.

 

Bombay

Intel NetStructure

Parent

Cache Appliance

NNTP

Parent Cache

Server

 

Zurich

London

Paris

Madrid

Oslo

Intel NetStructure Cache Appliance Child Caches

Figure 8 Hierarchy of news caching servers

In Figure 8 above, the parent news server for each of the child appliances is the parent appliance. The parent appliance is a child cache to the distant parent news server.

Appendix A Caching Solutions and Performance

137

Page 149
Image 149
Intel 1520 manual Nntp cache hierarchies, Bombay