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RSTP Spanning Tree problem - 1 9315 & 2 5372XL

Gilberto Civai
Occasional Contributor

RSTP Spanning Tree problem - 1 9315 & 2 5372XL

Hi to all.

I have the following situation: 1 Procurve 9315 (Core Switch) is connected on two different ports to 2 Procurve 5372XL switches (Access switches) via 1000LX mini GBIC. All works in this situation. But when I connect the redundancy fiber between two Procurve 5372XL (RSTP configured on all switches & LACP disabled on all uplinks ports), 1 of 2 5372XL switches drop the network.
Reading the log, the spanning tree is recalculating continuously the topology, without reaching a stable situation. RSTP on ports flaps from Listening to Forwarding to Blocking mode and returning to Listening. I have tried to change cost and priority of ports, but with no luck. Where is the problem? RSTP on 9315? Please HELP ME!!!

Thanks in advance!

Gilberto Civai

IT Department
Azienda Ospedaliera Senese
(Senese Hospital)
Kell van Daal
Respected Contributor

Re: RSTP Spanning Tree problem - 1 9315 & 2 5372XL

Can you check if PVST (Per Vlan Spanning Tree) is active?
If so, and you don't need it, try disabling it.
It could be the source of your problem.

Also check if the timers of spanning tree are the same on all switches.
Gilberto Civai
Occasional Contributor

Re: RSTP Spanning Tree problem - 1 9315 & 2 5372XL


Links between switches must transport multi VLAN traffic (3 or more VLANS) and PVST support on 9315 is disabled on ports connected to 2 5372XL.

No more hints ?


Gilberto Civai
Valued Contributor

Re: RSTP Spanning Tree problem - 1 9315 & 2 5372XL

What do you mean with : "1 of 2 5372XL switches drop the network" ? Is everything Ok between two other switches ?

Some ideas :
- Are all switches to the last firmware version ? (There are some bugs with Rstp on previous releases)
- On the 9315, is spanning-tree enabled on all propageated VLAN ?
> vlan * name * by port
> tagged ethe *
> spanning-tree
- Witch switch is the root bridge ?

The result of following commands, took without the redundancy link, could help :
- On the 9315 :
show 802-1w
show 802-1w det
- and on each 5300 :
show spanning-tree
show spanning-tree config
With previous recults, could you also tell on witch ports your three backbone links are connected ?

Bjorn Tore Paulen
Frequent Advisor

Re: RSTP Spanning Tree problem - 1 9315 & 2 5372XL

I have a similar problem with only 53xx-switches. Voip-applications get terminated and it creates very much hazzle.

It seems that the spanning-tree is recalculating all the time, and every time I get a 3-4 sec 'drop' in communication. After I disabled RSTP everything works fine. But I really would want it.

I got the tip of using 802.1D STP instead of RSTP, since RSTP is quite 'jumpy', and made for really big L2 networks (several hundred nodes) where normal STP never would make it. Haven't tried this one yet. Having a meeting with HP Techs tomorrow; will discuss it then.
Gilberto Civai
Occasional Contributor

Re: RSTP Spanning Tree problem - 1 9315 & 2 5372XL

I need RSTP for minimizing time of topology changes. 9315 must be the root bridge switch.


show 802-1w

in 9315 the response is

IEEE 802.1w is not configured on port-vlan X

for each vlan. In config i each vlan I have

spanning-tree rstp

and not

spanning-tree 802-1w

Could be an interaction problem with 53xx RSTP ? HP 9315 Backbone switch must interact also with Cisco Catalyst switches.

Can I change the configuration to try 802-1w RSTP instead of normal RSTP to verify if this is the problem ?

Thanks in advance for your replies.