Cambium AP/SM 450i version 14.2.1 causing spanning tree issues


Not sure if someone else is experiencing this but we have few setups where AP/SM radio links randomly drop spanning tree BPDU packets witch is causing peer inconsistency and ports blocking similar to a uniderectional situation on a fiber link.

Note the Radio links are reliable and never dropped when the spanning tree blocking happens.



Here is the syslog message logged by the Cisco switches at both ends of the radio link:

%SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer vlan id 102 on FastEthernet1/6 VLAN999

As you can see the switch is complaning because it's receiving a BPDU with vlan ID 102 instead a VLAN ID 999 which is the native vlan for this trunk port. Somehow the radios are changing the VLAN ID along the way.

Here is the switch port config on both ends of the trunk port:

switchport trunk allowed vlan 101-103,999
switchport trunk native vlan 999
switchport mode trunk

That's a pretty old firmware revision... any reason why you havn't updated to 15.X?

We running these radios in our SCADA network and they have been stable we didn't see any reason to upgrade. Is this a know issue that an 15.X version fixes?

Early version of firmware had various issues with Cisco devices... I did some searches and found THIS thread. Although this is not exactly what you're experiencing, I seem to recall some Cisco STP issues were resolved a long time ago... although I cannot find any direct evidence for you. You might want to try updating one AP and seeing if the issues clears up.

Thank you, I'll try that.