We are using an mixed environment 802.1d/802.1w and are seeing unusual high message age values on the trunk ports of end switches. This age is hopping between 15 to 20 causing loopguard to kick in.
The core is running 802.1d, the leave switches are running 802.1w
To further investigate the issue I have analyzed vlan 104:
Port 1 (GigabitEthernet0/1) of VLAN0104 is root forwarding Port path cost 3004, Port priority 128, Port Identifier 128.1. Designated root has priority 8192, address 000b.xxxx.xxxx Designated bridge has priority 16384, address 000b.xxxx.xxxx Designated port id is 128.129, designated path cost 3 Timers: message age 15, forward delay 0, hold 0 Number of transitions to forwarding state: 1390 Link type is point-to-point by default, Peer is STP Bpdu filter is enabled internally Loop guard is enabled by default on the port BPDU: sent 3924, received 11482485
The output above is of the end switch. In terms of hop count, this switch is 2 hops away (cost 4(1gb) + cost 3(2gb) + uplinkfast 3000=3007) from the root of vlan 104:
VLAN0104 Spanning tree enabled protocol rstp Root ID Priority 8192 Address 000b.xxxx.xxxx Cost 3007 Port 1 (GigabitEthernet0/1) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
The following output is the switch in between the core and SW1 which is displaying the correct message age being received in the BPDU send from the core:
SpanningTree enabled for vlan = 104
BPDU-related parameters port spanning tree enabled state forwarding port_id 0x8301 port number 0x301 path cost 3 message age (port/VLAN) 1(20) <--------------
If I understand the message age correctly, this should be 2 or 3 instead of 15+ as this is being refered to as a hop count value.
We have another switch connected to the same core switch, which is of the same type, 3560, and is running in pvst+, the same version the core switch is running. This switch is showing the correct message age for the same vlan 104:
Port 49 (GigabitEthernet0/1) of VLAN0104 is blocking Port path cost 3004, Port priority 128, Port Identifier 128.49. Designated root has priority 8192, address 000b.xxxx.xxxx Designated bridge has priority 16384, address 000b.xxxx.xxxx Designated port id is 128.193, designated path cost 3 Timers: message age 2, forward delay 0, hold 0 <--- Number of transitions to forwarding state: 0 Link type is point-to-point by default Loop guard is enabled on the port BPDU: sent 2, received 45424265
Could the high message age be related to the fact we are mixing RSTP + 802.1d?
The reason we would like to know the cause for this is we are also seeing many loopguard blocking/unblocking events on the end switches which have rstp enabled, and are experiencing a very high message age timer.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...