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

[Sean Hefty]

Hal Rosenstock wrote:
>>I believe that this still works.  Ipoib should leave all multicast groups, then 
>>rejoin when an event occurs.  As long as no other clients join the ipoib groups, 
>>this should work.
> 
> 
> Are you saying that IPoIB handles the event ? Does the multicast module
> cooperate (in terms of reregistering for a group it may think is already
> registered) ?

Ipoib handles the event.  It first leaves all multicast groups, then re-joins 
the groups.

Technically, the multicast module does _not_ cooperate.  That is, if the 
multicast module receives a join request for a group that it is already a member 
of, it will simply increment a reference count, rather than send a new join 
request.  (Assuming that the join states match.)

The multicast module should work in this specific case, since the only client is 
ipoib, and ipoib first leaves the group before re-joining.

- Sean