Re: IGMP for DTCP

[Emmanuel Duros <Emmanuel.Duros@sophia.inria.fr>]

>Given one feeder and one receiver, how can the receiver join to the DTCP
>multicast group?
>
>Before it gets the first DTCP hello, the receiver does not know whom to
>send the ICMP report to get membership of the DTCP group (224.0.1.124).

A feed sends HELLO msgs on the DTCP group (224.0.1.124) over the UDL
with a ttl of 1. There is no "routing" here, therefore there is no need
for a feed to know whether or not someone is listening to this mcast
group.

It is very similar to a host that can send Mcast packets over a LAN even
if no one on this LAN is listening to this Mcast group.

Since a feed has multiple interfaces, to make sure it sends by default
the HELLO packets over its UDL, something like this should work:

$ route add 224.0.1.124 unidir_interface

Emmanuel Duros