[ofa-general] [PATCH] ipoib: refresh path when remote lid changes

[Hal Rosenstock]

On Sat, Aug 1, 2009 at 8:01 AM, Yossi Etigin <yossi.openib at gmail.com> wrote:
>
> Hal Rosenstock wrote:
> >
> >     Yes, but AFAIK the only "bad" case is if the LID stays the same but
> >     LMC changes to a lower
> >     value. In this case the path refresh will not happen when it is
> >     supposed to.
> >
> >
> > What's the impact of that ?
> >
> > Also the LID can change at the same time as the LMC.
> >
> > I can't tell if all the possible cases are handled properly. Are they ?
> >
>
> Let's see:
> Only LID changes - handled correctly.
> LMC (and possibly LID) change - either we "catch" this, or we don't.
> If we do, the path and LMC will be refreshed so we will not keep refreshing
> the path forever (like it could have been if we didn't refresh the LMC).
> If we don't - ipoib packets will not reach the neighbour, which is the same
> situation there is today.

By handled correctly, you mean that the ARP request gets to the remote
node, is responded to, and the response makes it back and that is
treated as valid path indication, right ?

If so, is the original ARP request unicast or broadcast ?

If the request is unicast, couldn't it be sent using the wrong static
rate as isn't it using the original path parameters ?

Even if it is broadcast, if the original path parameters are still
used (like rate, etc.) at the local node, doesn't this assume a
homogeneous subnet ?