Multicast stream on the network needs to be forwarded to the querier

[nicolasjaud37000]

Hi,

I am looking for the RFC document that defines the rule for the data traffic for multicast. The following link states :

https://www.ravepubs.com/igmp-quirky-querier/

IGMP doesn’t have any way of “announcing” a stream, so to be able to manage a multicast stream, the querier needs to see it. This means that every single multicast stream on the network needs to be forwarded to the querier.

I would like to have a confirmation that even when the source and the receiver are on the same non-querier switch the source still has to send the stream back to the querier.

Thanks in advance for your help.

Nicolas

[Philip D'Ath]

>I would like to have a confirmation that even when the source and the receiver are on the same non-querier switch the source still has to send the stream back to the querier.

I don't have a reference - but that is also how I understand it to work.

[nicolasjaud37000]

Hi Philip,

Thanks for your reply.

This is the problem, I am looking for reference to prove it ...

I was doing some research over the week-end and the below is the closest I can find but still need an "expert" to confirm it:

https://tools.ietf.org/html/rfc4605

3.2. Supporting Senders

In order for senders to send from inside the proxy tree, all traffic
is forwarded towards the root. The multicast router(s) connected to
the wider multicast infrastructure should be configured to treat all
systems inside the proxy tree as though they were directly connected;
e.g., for Protocol Independent Multicast - Sparse Mode (PIM-SM)
[PIM-SM], these routers should Register-encapsulate traffic from new
sources within the proxy tree just as they would directly-connected
sources.

This information is likely to be manually configured; IGMP/MLD-based
multicast forwarding provides no way for the routers upstream of the
proxy tree to know what networks are connected to the proxy tree. If
the proxy topology is congruent with some routing topology, this
information MAY be learned from the routing protocol running on the
topology; e.g., a router may be configured to treat multicast packets
from all prefixes learned from routing protocol X via interface Y as
though they were from a directly connected system.

Nicolas