All things related to multicast

[Ross Finlayson <>]

At 09:09 AM 6/7/02, Gould, Aaron M (NRSW N60R11) wrote:
> UMTP (udp mcast tunneling protocol); Ross thanks.  I just look that up on
> google.com.  I was wondering if something like this existed.  It seems like
> a protocol that takes the place of IGMP.  Does it?

No!  UMTP <http://www.live.com/umtp.txt> is definitely *not* intended to 
'replace' IGMP, or real multicast routing protocol(s).  It is simply an 
application-level hack that can be used to tunnel UDP multicast packets 
over a non-multicast-routed cloud, by tunneling them in UDP unicast packets.

In an ideal world, hacks like UMTP would never be needed, as all routers 
would support multicast routing.  As this is an "Internet2" mailing list, I 
assume that most people on this list do, indeed live in (or at least, are 
working towards living in) such an 'ideal world' :-)

> would umtp solve me inability to join a mcast group on the MBone through a
> local internet cloud that doesn't run mcast routing protocols?

Yes, but your best solution would be to fix your "local internet cloud that 
doesn't run mcast routing protocols".  But anyway, to use UMTP, you will 
need to have access to (e.g., a user account on) a host (preferably one 
that's topologically near you) that's *already* on the MBone.  On this 
host, you would run a UMTP 'slave' such as "liveGate" <http://www.live.com/>.

Then, on a host on your local network (e.g., your desktop machine), you 
would run  UMTP 'master' software, with a tunnel to the other host.  One 
possible UMTP master to run is "multikit" <http://www.live.com/multikit/>, 
which is a SDP/SAP browser (somewhat similar to "sdr") with optional UMTP 
tunneling built in.  Another possible UMTP master is "liveGate for 
Intranets", which can be found (for the next week or so) at 
<http://www.live.com/lgfi4203/>.

        Ross.