[c-nsp] Trunking Catalyst to HP Procurve...

[A.L.M.Buxey at lboro.ac.uk]

Hi,
> Hopefully this will ring a bell with someone that has "been there done 
> that" and can save me a road trip with a sniffer...
> 
> We recently added a few HP ProCurve switches (2810s) at the access layer 
> using simple trunks back to our existing Ciscos (2950/2960/3550/3560s).
> 
> All is well with the exception that our network monitoring is turning up 
> discards on the trunks (roughly every 10 seconds).
> 
> I've tried disabling all of the negotiations that I can think of, e.g.,:

HPs doing link aggregation testing which is blipping the cisco?
turn LAG off on the HP switches is what I'd recommend.

> Also getting a *lot* of noisy spanning tree traffic seen on the Cisco side:
> 
> >      Protocol       Path    Pkts In   Chars In   Pkts Out  Chars Out
> >     
> > Spanning Tree    Process   17447867 1099182989       3219     204892
> 
> Ciscos are trunning default PVST, HPs are doing whatever they do out of 
> the box.  Not sure if this is an issue or just brain-dead old Catalyst 
> "show int switching" counter bug :-)

HPs and Ciscos generally are okay with PVST interop or 802.1w stuff.
I would advise that you use 'spanning-tree portfast trunk' on 
the trunk link between the cisco and HP - if a BPDU is then
seen on that cisco link then spanning-tree will kick into action

alan