[openib-general] Re: Failed multicast join withnew multicast module

[Sean Hefty]

Hal Rosenstock wrote:
> Note the MGRPs are MGIDs and switches are programmed with MLIDs and
> these can be 1:1 or many:1 depending on the implementation. Most do not
> do the many:1 but this is allowed by the spec. Also, note that switches
> know nothing about the groups themselves (only MLIDs and which ports) so
> most of the information is in the SM.

Is there any chance that someone using an "old" join can receive data on a group 
that was created after an SM restart?  My guess is that the QP would discard the 
message unless both the MLID and MGIDs matched, so there's probably not a real 
issue here.

> How ? Not all the group information is in the switches.

It's likely that the end nodes have the mcmember records from previous joins. 
Isn't that along with the switch information enough to reconstruct the group 
information?

- Sean