Interface problem with Cisco 2950G switch and SSG550M



  • I have two SSG550M in a Active/Passive configuration.  After a couple hours the 2950G shuts down the interface the SSG is connected to.  Below are log entries from the switch.  It looks like the SSG is bouncing some packets back to the switch confusing it.  Any ideas on this? These entries make it look like the switch is seeing its own BPDUs and keepalives.

    39w5d: %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer vlan id 13 on FastEthernet0/6 VLAN1.
    39w5d: %SPANTREE-2-BLOCK_PVID_PEER: Blocking FastEthernet0/6 on VLAN0013. Inconsistent peer vlan.
    39w5d: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking FastEthernet0/6 on VLAN0001. Inconsistent local vlan.
    39w5d: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking FastEthernet0/6 on VLAN0013. Port consistency restored.
    39w5d: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking FastEthernet0/6 on VLAN0001. Port consistency restored.
    39w5d: %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer vlan id 61 on FastEthernet0/6 VLAN1.
    39w5d: %SPANTREE-2-BLOCK_PVID_PEER: Blocking FastEthernet0/6 on VLAN0061. Inconsistent peer vlan.
    39w5d: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking FastEthernet0/6 on VLAN0001. Inconsistent local vlan.
    39w5d: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking FastEthernet0/6 on VLAN0061. Port consistency restored.
    39w5d: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking FastEthernet0/6 on VLAN0001. Port consistency restored.
    39w5d: %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer vlan id 12 on FastEthernet0/6 VLAN1.
    39w5d: %SPANTREE-2-BLOCK_PVID_PEER: Blocking FastEthernet0/6 on VLAN0012. Inconsistent peer vlan.
    39w5d: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking FastEthernet0/6 on VLAN0001. Inconsistent local vlan.
    39w5d: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking FastEthernet0/6 on VLAN0012. Port consistency restored.
    39w5d: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking FastEthernet0/6 on VLAN0001. Port consistency restored.
    39w5d: %ETHCNTR-3-LOOP_BACK_DETECTED: Loop-back detected on FastEthernet0/6. The port is forced to linkdown.
    39w5d: %ETHCNTR-3-LOOP_BACK_DETECTED: Loop-back detected on FastEthernet0/6. The port is forced to linkdown.



  • The switch has VLANs 1,12,13, & 61 configured.  The SSG only has sub-interface or 12.  I also just discovered spanning tree is disabled for 12 on the second switch.  I have SSG A&B attached to switch 1&2 respectively.  SSG A is supposed to be the master under normal conditions.  Switch 1&2 have 2 - gig connections between them, trunking and etherchanneled.  Switch 2 has spanning tree disabled for VLAN 12.  Not sure why original IBM contractors did that.  I have had SSG B active for a day now and it has some of the BPDU errors but not the loopback error yet.


  • Engineer

    OK, so where’s that “13” coming from? I seem to remember some funny business about where “zero” is when doing 802.1Q on Cisco’s. Perhaps an ‘off-by-one’ error?



  • I failed to mention the switch port is set to dot1q trunking and I have one subinterface for the SSG tagged with VLAN 12.


 

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