[openib-general] IPoIB broadcast MC group membership

[Hal Rosenstock]

Hi again Fab,

On Tue, 2006-02-21 at 01:10, Fabian Tillier wrote:
> Specifically, the problem relates to handling a 1X node trying to join
> the broadcast group, and what the retry policy should be.  If the
> group already exists at 4X, the join should fail if the SM follows the
> compliance statements in the IB spec.  

Correct; it should fail with ERR_REQ_INVALID

> Because the code allowed for
> the broadcast group not pre-existing (that is, a join could fail
> because the group wasn't created), it was unclear whether a failure of
> the join indicated that there was a setting incompatibility (1X vs.
> 4X), or just whether the group needed to be created.

A join to a nonexistent group should return
ERR_REQ_INSUFFICIENT_COMPONENTS.

Is this sufficient or is more needed ?

-- Hal

> Then, because
> the code handled the race where some other node beat it to creation
> and thus resulted in invalid settings, a failure in creation resulted
> in a retry of the whole process, staring with a new GET query.