[openib-general] IPoIB interface for unauthorized partition

[Eitan Zahavi]

Hi Hal,

> -----Original Message-----
> From: Hal Rosenstock [mailto:halr at voltaire.com]
> Sent: Monday, April 10, 2006 2:00 PM
> To: Eitan Zahavi
> Cc: Roland Dreier; openib-general at openib.org
> Subject: Re: [openib-general] IPoIB interface for unauthorized
partition
> 
> Hi Eitan,
> 
> On Mon, 2006-04-10 at 02:35, Eitan Zahavi wrote:
> > Hi Roland,
> >
> > Roland Dreier wrote:
> > >     Eitan> I thought the intent of the IB spec when defining P_Key
> > >     Eitan> index usage (and not P_Key value) was that the P_Key
values
> > >     Eitan> would never need to be known above the driver level.
To
> > >     Eitan> avoid exposing the P_Key values we could use P_Key
index
> > >     Eitan> for creating the IPoIB interfaces.
> > >
> > >     Eitan> Does it make sense to work on a patch that would setup
> > >     Eitan> IPoIB interfaces by the P_Key index (and not by P_Key
> > >     Eitan> value)?
> > >
> > > I don't see how this is feasible.  The index that a particular
P_Key
> > > lands at is completely undetermined -- if two nodes wanted to talk
on
> > > partition 0x8001 say, how does one know which interface to use
without
> > > knowing the index of that P_Key?
> > OK, I get it. Actually the way IPoIB defines the broadcast group
MGID exposes
> P_Key anyway.
> >
> > >
> > >     Eitan> Also I think the expected behavior for IPoIB should be
that
> > >     Eitan> IPoIB "child" interfaces should be "automatically"
> > >     Eitan> initialized by the code that brings up the interface
> > >     Eitan> (ifconfig scripts). All valid IPoIB partitions (valid =
> > >     Eitan> have corresponding broadcast groups) should be
> > >     Eitan> initialized. By doing so we provide a centralized
control
> > >     Eitan> of the partitions and their IPoIB interfaces through
the
> > >     Eitan> SM.
> > >
> > > Not sure if this is so.  I may want a partition strictly for
storage
> > > traffic something like that, so it doesn't make sense to create an
> > > IPoIB interface for that partition.
> > OpenSM provides this capability in the "partition policy":
> > Each partition is marked explicitly if to be used for IPoIB or not.
> > So through one file one could actually control the IPoIB interfaces
> > that will exist in the subnet.
> 
> The end node does not know the SM policy for that partition though.
> 
> > My intent is to write some extension to ifup for IPoIB such that all
sub
> > interfaces will be automatically started (based on pre-availability
of IPoIB
> > broadcast MGID).
> 
> If that were to be done, it would be cleanest if the child IPoIB
> interface was created only if that IPoIB broadcast group for that
> partition exists.
[EZ] This is exactly what I had in mind.
> 
> -- Hal
> 
> > >
> > >  - R.
> > >
> >