[multrans] Some comments on draft-jaclee-behave-v4v6-mcast-ps-01

[Stig Venaas <[e-mail]>]

Hi

I've read through this draft again and I have some comments.

First is the scope of the draft. Based on the title it seems
generic, but it seems to focus on a single provider, providing
multicast streams to its users? What if there are multiple
sources, or the users can also send. One example would be
RTCP, another multi-party conferencing. There may be more.

I think you either should make it clearer that this is the
scope, or try to make it more generic. I agree that what you
cover is probably the most common case though.

When you list the issue of AMT, I think you should note that
you lose the benefit of multicast between gateways and relays.
It's just unicast then.

In 3.4.1 it says:

    The content will be delivered once which is better utilized the
    network bandwidth.  However if the application relies on the IP
    information stored in the payload (e.g., SDP), then translation will
    break the application.

This is not obvious. E.g. the source of the SDP may be able to
include both IPv4 and IPv6 and groups, in the case it knows the
translation mappings. You are saying something like this in 4.2 too.

You generally seem to focus a lot on DS-Lite, but there may be other
alternatives. E.g. in 3.4.2. Maybe talk about tunneling in more general
terms, but note that DS-Lite is an example.

In 4.2, you first say that an ALG is needed. But as you explain
yourself, it can also be avoided.

Stig