[ofa-general] Re: OpenSM detection of duplicated GUIDs on loopback

[Sasha Khapyorsky]

Hi,

On 11:03 Tue 24 Jul     , Hal Rosenstock wrote:
>  On 7/24/07, Eitan Zahavi <eitan at mellanox.co.il> wrote:
> >
> >  *From:* Hal Rosenstock [mailto:hal.rosenstock at gmail.com]
> > *Sent:* Tuesday, July 24, 2007 5:53 PM
> > *To:* Eitan Zahavi
> > *Cc:* OpenFabrics General; Sasha Khapyorsky; Yevgeny Kliteynik
> > *Subject:* Re: OpenSM detection of duplicated GUIDs on loopback
> >
> >
> >
> > Hi Eitan,
> >
> > On 7/24/07, Eitan Zahavi <eitan at mellanox.co.il> wrote:
> > >
> > >  *Hi Hal,*
> > > **
> > > *What is this "loopback" connector used for?*
> > > *Does not seem to me like a very useful thing to do.*
> > >
> > **
> > Perhaps not but no reason OpenSM can't handle this more gracefully.

I don't have "loopback" plug, but used loopback connections for some
checks with simulator. There is nothing illegal, so I think it would be
better to support it.

> >  *Anyway, if it is not a production environment we could add a "debug
> > > mode" (-d flag option) to ignore this check.*
> > >
> > **
> > Why would a separate flag be needed ?
> > *[EZ] Since I do not see any other solution for the SM  to know it is
> > really a loop back plug rather then two devices with same GUID connected
> > back to back ...*

Also we saw the cases when port moving triggers duplicated GUIDs
detector (originally was reported on real fabric and it is trivially
reproducible in simulated environment).

So probably we need to find some better way to handle duplication GUID
detector (in general, not just for loopback). For example node_info
content could be compared. More ideas?

Sasha