Intel 1520 - Manual (Page 149)

Appendix A Caching Solutions and Performance 137
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.
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.
Zurich
Intel NetStructure Cache Appliance Child Caches
London
Intel NetStructure
Cache Appliance
Parent Cache Parent
NNTP
Server
Bombay
Paris Madrid Oslo