Re: about hier_code

On Friday 28 February 2003 11.51, atit_ldce wrote:
> can u explain what is purpose of follwing hier_code

http://www.squid-cache.org/Doc/FAQ/FAQ-6.html#ss6.10

> can u explain how ICP request are send and ICP reply handled in
> following configuration
>
> my squid having parent1 and parent2 as my parent and sibling1 and
> sibling2 as my siblings cache
>
> i have enabled query_icmp tag and source_echo
>
> how squid will pass request and how it will handle reply
>
> can u give me answer with taking into consideration priority of
> reply?.

1. On a cache miss Squid will send ICP requests to all your peers
(cache_peer allowing), and also an ICMP ping to the origin server.

2. When receiving ICP and ICMP replies from the peers (including
origin server) Squid notes

   a) Which peer responded quickest
   b) Which ICP peer responded with the lowest roundtrip time to the
origin server (requires each of the peer to be compiled with ICMP
pining, and to already know about the origin server).

   how this is done was discussed yesterday.

3. On the first ICP_HIT reply received, squid immediately selects this
peer.

4. If no ICP_HIT reply is received then the process waits for replies
from all peers or timeout, and then peerSelectFoo() continues and
selects which path to use.

I do am not sure exacly how the ICMP pings are used. For this see the
code.

Regards
Henrik
Received on Fri Feb 28 2003 - 01:22:24 MST