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Spanning-tree interoperability between HP and Cisco ?

 
Arthis
Occasional Advisor

Spanning-tree interoperability between HP and Cisco ?

Drawing1.jpg

 

On a site, I changed the Campus Core with an HP 10504.  Many Cisco switches are still connected on the HP (some in daisy-chaining).

 

RPVST+ is configured on Cisco and RSTP on HP.
RPVST+ is per-vlan and RSTP is per-instance.  Seems to be compatible but not sure.

 

I was wondering how the spanning-tree protocol deals with such a change.

 

[HP]dis stp root
 MSTID  Root Bridge ID                    ExtPathCost IntPathCost Root Port
   0        4096.b8af-6763-e67e   0                      0

 

HP is the root bridge for instance 0 (including vlan 1, 99). That's perfect

 

BUT.....on Cisco, the command "show spanning-tree vlan root' shows that the CISCO switch is the root bridge  for vlan 99 except vlan 1.

 

 

CISCO#show spanning-tree root

                                        Root    Hello Max Fwd
Vlan                                    Root ID                     Cost       Time  Age Dly  Root Port
----------------     --------------------           ---------    ----- --- ---  ------------
VLAN0001          4096 b8af.6763.e67e             4          2   20  15  Gi1/0/39
VLAN0099          8194 0025.8383.3400          0          2   20  15

 

Neither, the HP switch can become the Root Bridge for vlan 99.

 

Any idea ???  Should I migrate to PVST on HP ?

 

Herve

--------------

 

Another test on HP:

 

[HP] dis stp vlan 99

Error: Invalid STP Mode

 

[HP] dis stp vlan1

Error: Invalid STP Mode

 

 

1 REPLY
Peter_Debruyne
Honored Contributor

Re: Spanning-tree interoperability between HP and Cisco ?

Hi,

 

The HP comware switches (including the 105xx) support pvst, but not pvst+, so for failover times, it is probably best to stick with MSTP/RSTP on the HP side.

 

This is a doc about xSTP-PVST interop (based on procurve, but the logic applies to any vendor, including comware):

http://h10032.www1.hp.com/ctg/Manual/c02571903.pdf

 

Bottomline: Cisco will run standard STP on vlan 1 (native vlan), so this is the only one which will interact with the HP switches, HP switch will see the PVST packets as normal data packets in the user vlans.

 

Best regards,Peter.