Fwd: Re: [openib-general] static LID computationwithTS_HOST_DRIVER

[Yaron Haviv]

> -----Original Message-----
> From: openib-general-bounces at openib.org [mailto:openib-general-
> bounces at openib.org] On Behalf Of Roland Dreier
> Sent: Thursday, September 30, 2004 3:13 AM
> To: Michael Krause
> Cc: openib-general at openib.org
> Subject: Re: Fwd: Re: [openib-general] static LID
> computationwithTS_HOST_DRIVER
> 
>     Michael> The SM is the only entity that is supposed to assign LID
>     Michael> as well as the subnet prefix.  The SM should not trust
>     Michael> any CA / switch configuration if it has not configured it
>     Michael> thus should wipe it out and replace it with what it deems
>     Michael> best.
> 
> I don't see anything in the spec that forbids a CA from having an
> arbitrary value in PortInfo:LID after initialization but before the SM
> discovery (please correct me if I missed something).  I also don't see
> anything that forbids an SM implementation from providing a mechanism
> for preserving the LIDs it finds or administratively assigning LIDs.
> 

While I agree that other SM's in a recovery/merge phase should try and
preserve the LID's I think a CA shouldn't just like it is not supposed
to change its own P_Key table, and because it is not aware of the policy
and/or the bigger picture. 
Applications should be designed to deal with LID changes or other RC
connection failures.

But any way out of curiosity how do you generate a unique LID (locally
by the host) for every node in the fabric in a large fabric when the
ports are down and the nodes don't talk to each other ? (I hope not
through Ethernet :))

Or how do you anticipate the LMC value (LID spacing)? 

Yaron