I have the following
2 X 3com 4800 acting as the root of the network.
Various 3com and Cisco switches including a 6500.
To begin with both are set at defaults so the 3coms are running MSTP and the cisco are running common STP. On the 6500 while it is running RSTP (as default) it works OK unless I try to create a port-channel between the CISCO and 3com at which point it falls over.
SO I thought I would change the STP mode on the 6500 to MSTP, but now I get the following error message and the port gets blocked.
SPANTREE-2-PVSTSIM_FAIL: Blocking root port Gi2/1: Inconsitent inferior PVST BPDU received on VLAN 10, claiming root 32778:b4e9.b04c.8100
Can any one tell me what might be causing this issue? the 3com root bridges have both the "root primary and root secondary" command configured and all switches have all vlans added to instance 0 of MSTP.
I would like to get the STP consistence so that I can start migrating all the old 3com to the new 6500 with out worrying about STP issues. Does any one have some suggestions for best practices for 3com / cisco STP interopteribility.