[openib-general] IPv6oIB neighbour discover broken when MCGs overflow

[Hal Rosenstock]

On Fri, 2007-02-16 at 16:31, Roland Dreier wrote:
>  > Sure but I think this complicates the SL2VL tables in the subnet to
>  > accomodate this. I think a similar thing is true for PKeys. So to me
>  > this is an SM complexity issue when mapping multiple MGRPs to same MLID.
> 
> I'm still confused.  Aren't SL2VL and P_Key tables completely
> orthogonal from forwarding tables?

Sure they are separate mechanisms but by overloading MLIDs I think that
this ends up making them interdependent. I think it complicates the
use/configuration of those mechanisms depending on how flexible this is.
Either of those mechanisms could filter out the packet long before it
ever gets to some destination.

> Obviously there's no problem using
> multiple different SLs or P_Keys to reach the same endport using the
> same LID, so I don't understand why MLIDs would be different.

In terms of PKeys and overloaded MLIDs, p. 149 line 11 states:

"When a multicast LID is overloaded, the multicast groups sharing the
same MLID must have the same P_Key. This simplification is required to
allow switches and routers that implement optional P_Key enforcement for
multicast operations."

-- Hal

>  - R.