[openib-general] IPv6 and IPoIB scalability issue

[Jason Gunthorpe]

On Fri, Dec 01, 2006 at 01:53:45PM -0500, Hal Rosenstock wrote:
> > Generally IPv6 addresses should be constructed based on the EUI64 of
> > the IB interface. In this case the lower 24 bits of the SNM will be
> > the lower 24 bits of the EUI64. Thus in many cases the SNMs will be
> > cluster-unique..
> 
> It seems to depend on the low 24 bits of the IPv6 addresses in the
> subnet being the same (as to whether there is more than 1 member of
> these groups).

Correct. It is common practice for all IPv6 addresses to have the
lower 64 bits be the EUI64 of the interface. The administrator can
assign a different address, but that could be discouraged for
scalability reasoons.

> > Here is another thought.. Is there anything in the spec that says a
> > MGID must map to a MLID?
> 
> Yes. Here's the first one:
> p.149 line 3-8

Hmm. Thats a shame. It is a conformance statment too :< At least the
accepetance statements in C9 page 279+ don't specify to check that a
MGID is matched with a MLID so at least it should work with current
hardware.

Jason