Re: multicast question

From: Jon Kay <>
Date: Tue, 19 Oct 1999 16:13:10 +0000

> is there anything in squid's future (or maybe it's there now
> and i missed it) so that squid could do the equivalent of
> multicasting even if multicasting isn't turned on all the
> way to the source?

Our initial pushcache implementation, based on Squid, does
that. If you have a cloud of pushcaches, objects (defined by URLs) get
propagated automatically through common distribution trees.

> specifically: squid would see that two or more clients are
> receiving the same stream and just cut off one of the
> incoming streams. like multicasting, but without mbone.
It actually works the reverse of how you describe - efficient
distribution trees are automatically built up incrementally
as each cache shows interest.

Note: if you are after interactive, streaming multimedia, that is
currently a research issue. The infrastructure is available in the
pushcache, but it is still unclear what the best way to use it is.
Non-interactive multimedia is supported by caching multimedia objects

> we are a 2,000 (future) client isp, and all the clients are
> connected by ethernet lan. we're not sure that there is any
> limit to the number of T1s they can burn up if we don't
> implement caching.

The pushcache implementation is called Cuttlefish. The source code
(it's Open Source / GPL, just like Squid) can be downloaded from A development environment, called the
PushAp Kit, is available to allow programs to distribute data
using pushcache mechanisms.

For more information, see

Received on Tue Oct 19 1999 - 15:31:45 MDT

This archive was generated by hypermail pre-2.1.9 : Tue Dec 09 2003 - 16:48:59 MST