MBone access

Fri Mar 30 17:04:09 UTC 2001

> 	I'm curious what barriers are keeping multicast from
> being deployed at the edges.  Does your upstream not support
> multicast connectivity, or is it an education issue in getting
> connected?

Well, if we go out to the consumer edge, you'll find several
providers deploy technologies that have bad scaling properties
with multicast.

If I've understood correctly, many DSL providers do the provider end
of DSL as ATM, and with no "multicast smarts" at the point where the
DSL circuits actually fan out (DSLAM?).  This creates duplicate
traffic on the "pure ATM stretch".  If the DSL provider overbooks his
ATM capacity (which is apparently fairly common) compared to the
number of DSL circuits he terminates, well..., it's not helping.

I'm sure there are other examples of more or less actively
multicast-unfriendly network technologies in this market segment.

Of course, having tunnels run willy-nilly over your unicast infra-
structure isn't exactly ideal either.

Regards,

- Håvard