[squid-users] Effective cache peering

Hello again.

I've been reading a little bit on cache peering in the FAQ, and I have a
fairly good handle on how it works in general, now. I guess I have a couple
of questions, though, that I'd appreciate answered by someone who's
implemented it already.

Cache server #1: I want to configure him to think "allow cache #2 to ask me
if I have content he wants".

Cache server #2: I want to configure him to think "I'm going to check my
local cache, then ask Cache #1 if he has my content, then check the
Internet's content".

What's the absolute minimum configuration for this? I imagine it involves a
cache_peer directive and an ACL of some kind. The communications uses ICP
on port 3130/udp, correct? If Cache #1 does not have the content cache #2
is asking for, will it retrieve it? Are there any pitfalls I should know in
general - i.e. what is the behavior by cache #2 if cache #1 is unreachable?

Thanks for your input...

Paul