[squid-users] ICP behaviour question ?

From: <vincent.blondel_at_ing.be>
Date: Tue, 14 Apr 2009 16:59:11 +0200

Hello all,

I am doing some tests for implementing ICp in our SQUID platform
including two level of SQUID devices, the SQUID proxies the users are
connected on and the Gateways directly connected on the internet.

After reading some old pdf documents I found on the net it seems if I
good understood the way it works, an icp query is sent to all parent
caches each time a url must be retrieved from the internet.

config at proxy level ..

icp_port 3130
icp_query_timeout 0
maximum_icp_query_timeout 50 # (milliseconds)
dead_peer_timeout 1 second
log_icp_queries off
icp_hit_stale off
icp_access deny all

config at gateway level ..

icp_port 3130
log_icp_queries off
icp_hit_stale off
icp_access allow srcip_internalproxies
icp_access deny all

I made a very little test for requesting from my proxy (sbeaskda) a web
resource from the freebsd website. This proxy gets two parents (sbepskcw
and sbepskcy).

# squidclient http://www.freebsd.org/layout/css/fixed.css

# snoop ...

sbeaskda -> sbepskcw UDP D=3130 S=3130 LEN=76
sbeaskda -> sbepskcy UDP D=3130 S=3130 LEN=76
sbepskcw -> sbeaskda UDP D=3130 S=3130 LEN=72
sbepskcy -> sbeaskda UDP D=3130 S=3130 LEN=72
sbeaskda -> sbepskcw HTTP GET
http://www.freebsd.org/layout/css/fixed.css HTTP/1.0
sbepskcw -> sbeaskda HTTP (proxy) R port=58841
sbepskcw -> sbeaskda HTTP HTTP/1.0 200 OK
sbeaskda -> sbepskcw HTTP (proxy) C port=58841

We see the proxy sending an udp request to port 3130 to all the parents,
each of them replying to the request. We then see the http query sent to
sbepskcw.

This is all working fine but I also read in this same pdf that if the
object retrieved is not too large, the gateway can include the object
(in this case the css page) in the udp reply so the proxy client does
not have to send an icp and http query for each object.

so my question is ..

Is this still the case with SQUID ?

If yes, why not in this case ?

If not, do I have to enable something for this ?

many thks for your help.
Vincent
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Received on Tue Apr 14 2009 - 14:59:42 MDT

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