All things related to multicast

[Hitoshi Asaeda <>]

> > or how could the client join session if they are behind a NAT ?
> > Are the tunneled via "http" ?
> 
> CR only provides a session announcement function. It does not invoke
> IGMP/MLD join/leave and does not control routing functions.

Ah, did you ask how a multicast client application behind NAT can join
multicast sessions in general (not via CR)?

Ideally, NAT box must forward the client's IGMP/MLD messages. In that
case, If NAT can enable the function of IGMP/MLD proxy, it forwards
the downstream IGMP/MLD messages to its upstream router.
If NAT does not have the proxy function, then the application should
use AMT to bypass the NAT by establishing unicast UDP tunnel. AMT
suports to forward both multicast data and IGMP/MLD messages. One big
problem here is that AMT must be supported by both client hosts and
upstream routers (whether it's adjacent or not) and we need to break
its deployement barrier and operational or management difficulties.
--
Hitoshi Asaeda