[openib-general] [PATCH] IPOIB: Use a GRH when appropriate for unicast packets

[Hal Rosenstock]

On Wed, 2007-02-07 at 15:24, Sean Hefty wrote:
> > I didn't get too far on getting CMA to work. Beyond the bad HopLimit
> > feild I was seeing Hal pointed out a number of problems in IBA that
> > would prevent it from working as is :<
> 
> I've started thinking about what it would take to get the rdma cm to work across 
> a router.  I think the rdma cm may need to treat IPv6 addresses as a GID for 
> this to work across subnets, versus trying to map an ipoib IP address to a GID 
> based on ARP.

An IB GID is IPv6 like but not an IPv6 address so I don't think this is
a good idea and don't see how you get around mapping IP addresses to
GIDs in an IB routed network given the way things are spec'd. I think
that the RDMA CM assumes a single IPoIB subnet. Does it work when the
destination is on another subnet ? I think there are some unaddressed
gateway issues here to make that work and these may have been punted
(during spec time). Arkady might be a good person to comment on this.

-- Hal

> - Sean
> 
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