icp and multiple siblings + parent, selection mechanism

How are ICP-requests to multiple siblings and a parent handled?

I have a setup up with 2 siblings and a parent. If an URL is requested and
it can't be served from the local cache an ICP-request is send out and
eventually the URL is fetched from one of the siblings, the parent or direct.

My questions are:

1) Is an ICP-request send to all the siblings and the parent at the same
time? So the parent and the sibling are handled in the same way at this time
(ignoring what will happen if all reply with a miss) Or are the probed 1 by
one? (just guessing)

I ask this question because I got the impression that the siblings get much
lesser numbers of ICP-requests than my parent. This suggests that the parent
is preferred and only if this one gives a MISS the siblings are tried.

2) Assuming we get an ICP_HIT from more than one sibling/parent, who gets to
deliver the data (TCP)? Is this who replies first, is the sequence in
squid.conf important or is the parent handled differently than the sibling?
(see question 1)

Thanks in advance for your comments,

Marc

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Marc van Selm
NATO C3 Agency
Communication Systems Division, A-Branch
E-Mail: marc.van.selm@nc3a.nato.int
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Private: selm@cistron.nl, selm@het.net, http://www.cistron.nl/~selm
Received on Tue May 13 1997 - 03:26:06 MDT