Avaya 5510/5520 identify rstp root bridge or is there an issue?

[novice]

Hi

Came across a post on this forum suggesting to use the command
show spanning-tree rstp status
to identify rstp root bridge. Hence issued the command on network switches (mixture of 5010, 5020, stacked, unstacked running  v6.3.6.016 / v6.2.4.010)
The output is confusing because my understanding is that the output
Stp Root cost: 0
indicates the switch to be a root bridge.(Unless my understanding is incorrect) And there can only be one root bridge but many switches are showing Stp Root cost: 0. 
Below is the command output. Please advise how can the root bridge be identified?


sw1#show spanning-tree rstp status
Designated Root:        80:00:00:0E:40:B4:74:**
Stp Root Cost:          0
Stp Root Port:          0
Stp Max Age:            20 seconds
Stp Hello Time:         2 seconds
Stp Forward Delay Time: 15 seconds
Connected to 10.10.10.87.
sw2#show spanning-tree rstp status
Designated Root:        80:00:00:1A:8F:83:D8:**
Stp Root Cost:          0
Stp Root Port:          0
Stp Max Age:            20 seconds
Stp Hello Time:         2 seconds
Stp Forward Delay Time: 15 seconds
Connected to 10.10.10.88.
sw3#show spanning-tree rstp status
Designated Root:        80:00:00:15:70:38:0A:**
Stp Root Cost:          40200
Stp Root Port:          45
Stp Max Age:            20 seconds
Stp Hello Time:         2 seconds
Stp Forward Delay Time: 15 seconds
Connected to 10.10.11.90.
5510-48T#show spanning-tree rstp status
Designated Root:        80:00:00:15:9B:C4:B4:**
Stp Root Cost:          0
Stp Root Port:          0
Stp Max Age:            20 seconds
Stp Hello Time:         2 seconds
Stp Forward Delay Time: 15 seconds
Connected to 10.10.11.123.
5520-48T-PWR#show spanning-tree rstp status
Designated Root:        80:00:00:19:E1:9C:94:**
Stp Root Cost:          0
Stp Root Port:          0
Stp Max Age:            20 seconds
Stp Hello Time:         2 seconds
Stp Forward Delay Time: 15 seconds
Connected to 10.10.11.94.
5520-48T-PWR#show spanning-tree rstp status
Designated Root:        80:00:00:11:F9:2F:60:**
Stp Root Cost:          0
Stp Root Port:          0
Stp Max Age:            20 seconds
Stp Hello Time:         2 seconds
Stp Forward Delay Time: 15 seconds
Connected to 10.10.11.107.
5510-48T#show spanning-tree rstp status
% Invalid input detected at '^' marker.
5510-48T#show spanning-tree config
Bridge Priority (hex):      8000
Designated Root:            80000019E12B50**
Root Port:                  Unit:0  Port:0
Root Path Cost:             0
Hello Time:                 2 seconds
Maximum Age Time:           20 seconds
Forward Delay:              15 seconds
Bridge Hello Time:          2 seconds
Bridge Maximum Age Time:    20 seconds
Bridge Forward Delay:       15 seconds
Tagged BPDU on tagged port: No
VID used for Tagged BPDU:   4001
STP Group State:            Active
STP Multicast Address:      01-80-C2-00-00-00

Connected to 10.10.11.93.
sw6#show spanning-tree rstp status
Designated Root:        80:00:00:0F:06:7E:58:**
Stp Root Cost:          0
Stp Root Port:          0
Stp Max Age:            20 seconds
Stp Hello Time:         2 seconds
Stp Forward Delay Time: 15 seconds
Connected to 10.10.11.176.
sw4#show spanning-tree rstp status
Designated Root:        80:00:00:15:70:38:0A:**
Stp Root Cost:          20000
Stp Root Port:          1/43
Stp Max Age:            20 seconds
Stp Hello Time:         2 seconds
Stp Forward Delay Time: 15 seconds
Connected to 10.10.11.91.
5510-48T#show spanning-tree rstp status
Designated Root:        80:00:00:12:83:0B:E8:**
Stp Root Cost:          0
Stp Root Port:          0
Stp Max Age:            20 seconds
Stp Hello Time:         2 seconds
Stp Forward Delay Time: 15 seconds
Connected to 10.10.11.155.
sw5#show spanning-tree rstp status
Designated Root:        80:00:00:15:9B:C2:78:**
Stp Root Cost:          20000
Stp Root Port:          4/33
Stp Max Age:            20 seconds
Stp Hello Time:         2 seconds
Stp Forward Delay Time: 15 seconds


Thanks in advance.

 

[pat2012]

To properly interpret this, a diagram of the network would be required.  Do you use an MLTs?  These would/should have STP disabled so the switch would not participate in Spanning Tree - Root Cost:0, Root Port:0.  At least that's what I'm thinking.  :-)

[novice]

To properly interpret this, a diagram of the network would be required.  Do you use an MLTs?  These would/should have STP disabled so the switch would not participate in Spanning Tree - Root Cost:0, Root Port:0.  At least that's what I'm thinking.  :-)

Hi
Thanks for your reply. I had been busy hence couldn't reply. May be following will be helpful to someone in future.
What I found was, STP Learning was disabled on the underlying ports in the MLT.

Avaya-5510-48T#show running-config module stp
! Embedded ASCII Configuration Generator Script
! Base model = Ethernet Routing Switch 5510-48T
!
!
!
!
! Displaying only parameters different to default
!================================================
enable
configure terminal
!
! *** RSTP (Phase 1) ***
!
!The Spanning tree operation mode cannot be changed without rebooting.
!The Spanning tree operation mode is required to be set to RSTP before
!loading this ASCII configuration file.
spanning-tree mode rstp
spanning-tree rstp priority 2000
!
! *** RSTP (Phase 2) ***
!
interface FastEthernet ALL
spanning-tree rstp port 45,47 learning disable
exit

Hence switches saw themselves as the root bridge. So I enabled Learning using the following commands

conf t
int fastEthernet 45,47
spanning-tree rstp port 45,47 learning enable
exit

Above config solved the root bridge issue. Furthermore I added some stp optimization commands to bring ports connected to edge devices like computers, printer up (forwarding state) asap without going usual spanning Blocking, Listening, Learning and then forwarding. Also to disable and auto recover if bpdu is detected on the port it shouldn't be seen on because of human error or a network loop.

conf t
interface fastEthernet 6-44
spanning-tree rstp port 6-44 edge-port true (this is same as Cisco spanning tree portfast)
spanning-tree bpdu-filtering port 6-44 enable timeout 60 (bpdu-filtering will block the port if a spanning tree bpdu is seen on ports between fastethernet 6 to 44 for sixty seconds and will automatically enable the port after checking if there are no more bpdu just after 60th sec. If bpdu are still seen after 60sec port will not be auto recovered. This feature is similar to Cisco error disable and error recovery. timeout is a must feature if you have a large network and you don't want to run around console to every switch to recover while the network is down for the business. One can also choose to leave the port disabled and not auto recover after 60 sec. By default timeout value is 120 sec on Avaya 5510 ). On cisco I think it use to be 300sec.

example command the output excerpt.
#sh running-config ver module stp
spanning-tree bpdu-filtering port 5/10 enable timeout 120

Thanks again.