[ofa-general] More questions/comments on IPv6 SNM consolidation option in OpenSM

[Hal Rosenstock]

Ira,

The IPv6 SNM consolidation option in OpenSM currently collapses the SNM
groups down to 1 group aliased group. However, in a heterogeneous
network, not all ports will be able to meet certain group parameters
(MTU, rate). This has been discussed on the list before. My current read
of the code indicates that these joins would be rejected. Is that
right ? If so, my question is why not allow them to create and join with
their original real multicast group for this case ? The downside would
be that if there were a lot of ports like this, then the consolidation
would reduce the number of groups but maybe not enough. So would we then
want an additional option for doing this (and what the default should
be) ? One cut on the default would be to keep it the same as now but
does that really matter ? Ideally, those additional SNM groups would be
collapsed too. I think that aspect was dealt with in Jason's approach to
this in a thread entitled "IPv6 and IPoIB scalability issue":
http://lists.openfabrics.org/pipermail/general/2006-November/029621.html
in which he proposed an MGID range for collapsing IPv6 SNM groups.

Also, have you tried IPv6 SNM consolidation with multiple partitions ? I
may have more on this aspect later.

-- Hal