Large delays (2 minute) with dummynet

[josh]

I hope this is the right list to post to.

I'd like to delay a shoutcast stream by around 2 minutes.  This
shoutcast server is used to broadcast commentary on live games and
the delay is needed so teams can't gain an advantage by hearing the
commentary to learn where/what the other team is doing.  I've
checked the shoutcast forums and it seems there's nothing I can do
to the shoutcast daemon to get this delay.  Shoutcast listens on
tcp/8001 for an input stream, and tcp/8000 for listeners to connect
to.

With 100 streams each using 48kbps, how practical is it to put them
all through a dummynet pipe with a delay of 120000ms?  I figure
that'll require 100 * 48 / 8 * 120 / 1024 = 70MB of buffering in
dummynet.  That's heaps!  Is that possible?  Is that using mbufs?
What would have to be tweaked up?

I guess it'd be better if I could just add the 2mins of delay to
the input stream so the delay buffer is smaller and fixed, but I
don't know how the shoutcast protocol would like that or how the
different TCP implementations would like it.  Would ACKs be coming
back to the shoutcaster 2 minutes late?

Ideally it'd be best to have all this buffering happen intelligently
in userland, but I can't find anything to do that.  Am I barking up
the wrong tree by looking at dummynet?

Cheers,
      Josh