[j-nsp] Uplink failure detection in EX series

[Tore Anderson]

Hi,

* Keegan Holley

> I'm not aware of a protocol that can shut down switchports.  There's
> something in the optical world that will shut down a gig port if the
> sonet links it traverses flap, but that wouldn't help here.  Op-scripts
> maybe?

The EX2500 has the required functionality, the Cisco Nexus fabric
extenders too (or so I'm told).

>     I want to avoid repeats of an interesting failure I just experienced: an
>     EX top-of-rack switch lost both its uplinks simultaneously, most likely
>     due to lacpd failing to do its job - both uplinks were 802.3ad LAGs, and
>     rebooting the switch solved the problem in the end.
> 
> 
> That sounds like a bug of some sort.  I'd probably fix it by upgrading
> to code where the bug was fixed.  What code are you running?

No doubt a bug, and probably fixable by upgrading - the switch in
question was running 10.1R1.8...

However, it would be nice to have such functionality in any case. I
would not need to waste ports on dual uplinks, for example.

> Maybe you can write a script that pings out periodically and fails over
> the bundles if the ping fails.  Probably easier than opscripts.  If not
> there's always spanning-tree. ;)

I think both those approaches would cause more problems than they solve.
The Linux bonding driver actually has ping based probing functionality,
but from experience, the ping target is more likely to go down than
anything else happening (or, if it was found on the same switch, it
wouldn't help at all). And STP just terrifies me - I try to rely on it
as little as possible.

Best regards,
-- 
Tore Anderson
Redpill Linpro AS - http://www.redpill-linpro.com
Tel: +47 21 54 41 27