[openib-general] IPoIB interface for unauthorized partition

[Hal Rosenstock]

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.

-- Hal

> > 
> >  - R.
> > 
>