3750 and HP Procurve - inconsistent peer vlan

[jlmickens]

Hi,

I'm in the process of trying to migrate the core of our network from an HP ProCurve 5308 to a Cisco 3750 stack and am having some issues.  The two pieces of equipment are connected with an etherchannel(HP trunk) for redundancy.  They have been connected for a couple of months with no issues.  Until this week, only two vlans had been tagged on the connection from the 5308 to the 3750 - well, tagged is not exactly accurate - one was tagged (vlan 10) and the other untagged (vlan 1) in order to match the native vlan on the Cisco.  This week, I needed to start adding some of the other vlans to the 3750 stack.  The vlans exist already on both devices.  I went into the 5308 and set it to start tagging vlans 3-5 and 75 on the link to the 3750 stack.  When I did, I got several errors on the 3750 stack regarding vlans 3 and 4 and they both went into a blocking state on the connection.  They have been in that state ever since.

From my syslog server:

1731: Jan 26 05:48:32: %SPANTREE-2-BLOCK_PVID_PEER: Blocking Port-channel1 on VLAN0003. Inconsistent peer vlan.
1731: Jan 26 05:48:32: %SPANTREE-2-BLOCK_PVID_PEER: Blocking Port-channel1 on VLAN0003. Inconsistent peer vlan.
1730: Jan 26 05:48:32: %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer vlan id 3 on Port-channel1 VLAN4.
1730: Jan 26 05:48:32: %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer vlan id 3 on Port-channel1 VLAN4.

Everything I've read so far regarding this type of error point to a difference in the native vlan setup for both sides, but that's not the case here, as both sides are set for native vlan 1 and have been working that way for several months now.  I had a similar issue with vlans 6 and 8 between these two devices when I first went to this setup and it would shut down the interfaces instead of just the vlans.  I wound up having to move those two to separate connections exclusive to the vlans to get them to work (that's probably a whole other issue).

Any ideas would be appreciated.

SWHQCORE#sh spanning-tree inc

Name                 Interface                Inconsistency
-------------------- ------------------------ ------------------
VLAN0003             Port-channel1            Port VLAN ID Mismatch
VLAN0004             Port-channel1            Port VLAN ID Mismatch

Number of inconsistent ports (segments) in the system : 2

[PETER EIJSBERG · Accepted solution]

You can mirror the traffic on vlan 4 to a laptop with wireshark, and then search for the BPDUs. They should have the MAC of the sending switch in it. But if you do not use spanning tree in your network, you can also put a bpdufilter at the edge of the HP network on that vlan. It might even work if you just put a bpdufilter on the ports of the Cisco switch that form the etherchannel. That should make the problem disappear.

My theory is that one of those fiber links has native vlan 4 on one side and native vlan 3 on the other side (with a Cisco switch sending out the BPDUs)

[jlmickens]

It sounds like filtering might be the best option to get things going faster.  Do I need to put those on the two etherchannel ports individually, or on the (gi2/0/24, gi3/0/24) or do I put it on the etherchannel itself (po1).

[PETER EIJSBERG]

I think you would have to put the bpdufilters on the physical interface, not the port channel

[jlmickens]

An update...

I finally got time to work on this more.  I put the bpdufilter on the pysical interfaces and then started tagging VLAN 4 from the HP ProCurve again.  VLAN 4 went down again due to the inconsistent peer vlan id, but the difference is that only VLAN 4 went down, not the entire etherchannel and it's two physical ports.  Then I added the bpdu filter to the port channel and VLAN 4 came up.

[jlmickens]

How do I search for the BPDU's.  I grabbed a packet capture, but I'm fairly n00bish to packet captures so I'm not sure what I'm looking for.