Seeking assistance regarding Spantree-2-Loopguard Blocking events associated with Cisco network equipment attached to PTP-450i AP’s and SU’s.
This has been discovered on all network systems attached to multi-point radios.
Currently using Firmware 16.1.1.
Otherwise the network is operating nominally. I don’t believe this is a link quality issue since it appears across systems remotely located from each other.
Network interfaces are locked to 100 Mbps Full Duplex across both the radio and Cisco network interface ports.
Below is a portion of an event log from the Cisco equipment detailing the Spanning Tree Block events.
Oct 14 12:52:39.183 CDT: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port GigabitEthernet1/0/24 on VLAN0379. Oct 14 12:52:39.216 CDT: %SPANTREE-2-LOOPGUARD_UNBLOCK: Loop guard unblocking port GigabitEthernet1/0/24 on VLAN0379 . Oct 20 23:54:04.868 CDT: %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer vlan id 379 on GigabitEther net1/0/24 VLAN78. Oct 20 23:54:04.868 CDT: %SPANTREE-2-BLOCK_PVID_PEER: Blocking GigabitEthernet1/0/24 on VLAN0379. Inconsistent peer vlan. Oct 20 23:54:04.868 CDT: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking GigabitEthernet1/0/24 on VLAN0078. Inconsistent loca l vlan. Oct 20 23:54:19.897 CDT: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/24 on VLAN0379. Port consis tency restored. Oct 20 23:54:19.897 CDT: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/24 on VLAN0078. Port consis tency restored. Oct 27 13:08:15.966 CDT: %SYS-5-CONFIG_I: Configured from console by b118703 on vty0 (10.11.166.12) Oct 29 22:58:16.487 CDT: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port GigabitEthernet1/0/24 on VLAN0379. Oct 29 22:58:16.531 CDT: %SPANTREE-2-LOOPGUARD_UNBLOCK: Loop guard unblocking port GigabitEthernet1/0/24 on VLAN0379
I am also experiencing same issue with Port consistency. Any solution ?
Feb 8 07:03:11.150: %SPANTREE-2-BLOCK_PVID_PEER: Blocking GigabitEthernet1/0/16 on VLAN0001. Inconsistent peer vlan.
Feb 8 07:03:11.150: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking GigabitEthernet1/0/16 on VLAN0023. Inconsistent local vlan.
Feb 8 07:10:17.987: %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on GigabitEthernet1/0/16 (23), with Switch GigabitEthernet1/0/48 (1).
Feb 8 07:10:37.879: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/16 on VLAN0001. Port consistency restored.
Feb 8 07:10:37.879: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking GigabitEthernet1/0/16 on VLAN0023. Port consistency restored.
Feb 8 07:14:21.914: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/15, changed state to down
I have the same problem with an AP / SM pmp450i mount.
I installed Firmware 20.2
But still the same problem.
000249: May 5 14:36:59.554 EDT: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port GigabitEthernet1/1 on VLAN0083.
000250: May 5 14:37:00.669 EDT: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port GigabitEthernet1/1 on VLAN0097.
000251: May 5 14:37:00.672 EDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan97, changed state to down
000252: .May 5 14:38:31.768 EDT: %SPANTREE-2-LOOPGUARD_UNBLOCK: Loop guard unblocking port GigabitEthernet1/1 on VLAN0083.
000253: .May 5 14:38:32.883 EDT: %SPANTREE-2-LOOPGUARD_UNBLOCK: Loop guard unblocking port GigabitEthernet1/1 on VLAN0097.
000254: .May 5 14:38:32.890 EDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan97, changed state to up
000255: May 5 14:39:21.982 EDT: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port GigabitEthernet1/1 on VLAN0098.
000256: May 5 14:39:22.982 EDT: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port GigabitEthernet1/1 on VLAN0097.
000257: May 5 14:39:22.985 EDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan97, changed state to down
000258: .May 5 14:40:29.148 EDT: %SPANTREE-2-LOOPGUARD_UNBLOCK: Loop guard unblocking port GigabitEthernet1/1 on VLAN0097.
000259: .May 5 14:40:29.155 EDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan97, changed state to up
000260: .May 5 14:40:30.151 EDT: %SPANTREE-2-LOOPGUARD_UNBLOCK: Loop guard unblocking port GigabitEthernet1/1 on VLAN0098.
000261: May 5 14:43:27.530 EDT: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port GigabitEthernet1/1 on VLAN0097.
000262: May 5 14:43:27.534 EDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan97, changed state to down
000263: .May 5 14:43:29.683 EDT: %SPANTREE-2-LOOPGUARD_UNBLOCK: Loop guard unblocking port GigabitEthernet1/1 on VLAN0083.
000264: .May 5 14:43:29.722 EDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan97, changed state to up
000265: May 5 14:51:34.682 EDT: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port GigabitEthernet1/1 on VLAN0083.
000266: May 5 14:51:34.720 EDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan97, changed state to down
000267: .May 5 14:51:36.688 EDT: %SPANTREE-2-LOOPGUARD_UNBLOCK: Loop guard unblocking port GigabitEthernet1/1 on VLAN0083.
000268: .May 5 14:51:36.727 EDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan97, changed state to up
000269: .May 5 14:52:26.777 EDT: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port GigabitEthernet1/1 on VLAN0083.
000270: .May 5 14:52:26.791 EDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan97, changed state to down
000271: .May 5 14:52:28.787 EDT: %SPANTREE-2-LOOPGUARD_UNBLOCK: Loop guard unblocking port GigabitEthernet1/1 on VLAN0083.
000272: .May 5 14:52:28.825 EDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan97, changed state to up
000273: .May 5 14:54:00.942 EDT: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port GigabitEthernet1/1 on VLAN0083.
000274: .May 5 14:54:00.981 EDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan97, changed state to down
000275: .May 5 14:54:02.935 EDT: %SPANTREE-2-LOOPGUARD_UNBLOCK: Loop guard unblocking port GigabitEthernet1/1 on VLAN0097.
000276: .May 5 14:54:02.945 EDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan97, changed state to up
000277: .May 5 14:54:03.938 EDT: %SPANTREE-2-LOOPGUARD_UNBLOCK: Loop guard unblocking port GigabitEthernet1/1 on VLAN0098.
000278: .May 5 14:54:22.970 EDT: %SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port GigabitEthernet1/1 on VLAN0097.
000279: .May 5 14:54:22.974 EDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan97, changed state to down
I fond the problem on my 5 Ghz link. There is brief, intermittent interference on the carrier.
The signal level remains constant but the signal to noise ratio goes down.
When this problem occurs, the switch logs SPANTREE-LOOPGUARD-BLOCK.
I’ve seen this recently on a few CBRS PTP links as well, connected to netonix switches. When the modulation rate drops under heavy traffic, STP blocks traffic on the port long enough to cause OSPF adjacency changes to trigger.
Disabling STP on the port facing the 450 radios resolves the problem in my case.
