The IP Over NBMA (ION) Archive

[Albert Manfredi <manfredi@engr05.comsys.rockwell.com>]

mohta@necom830.hpcl.titech.ac.jp wrote:

[ ... ]

> > It is *not* unicast-only MPOA.  MPOA *does* support multicast; it just
> > doesn't use NHRP-derived shortcuts for multicast.
> 
> I'm confused.
> 
> Doesn't it mean that MPOA does not need NHRP?

MPOA might not use NHRP per se, but I have to agree with you that the
UNI 3.1 version of MPOA seems like it will have the same inscalability
problems as NHRP for multicast. This ain't magic, after all. The
fundamental problem is that the source of the multicast must keep track
of and set up the pt-mpt VC to reach all members of the group. That
won't change with any UNI 3.1-based solutions.

However, since I know that scalable multicast schemes are possible
within the context of ATM by itself, I'm not nearly as pessimistic about
this issue as you are.

> > 2. Note that three years ago, the IETF specifically decided that:
> > unicast-only 1577 was worth having because it was the first step toward
> > multicast capable IP-over-ATM.
> 
> Of course.
> 
> RFC 1577 was a step toward multicast capable IP-over-ATM.

A strange assertion. I must have missed that subtlety.

Bert
manfredi@engr05.comsys.rockwell.com