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Vlan not showing in spanning tree

tonyplueard
Level 1
Level 1

I have a Catalyst 1000. I had to replace an existing switch with this one. We are running VTP. My problem is that I have a vlan not showing up in spanning tree. 

 

show vlan brief

203 VLAN0203 active Gi1/0/1, Gi1/0/7, Gi1/0/8, Gi1/0/9

 

Show spanning-tree summary

sh spanning-tree summary
Switch is in rapid-pvst mode
Root bridge for: none
EtherChannel misconfig guard is enabled
Extended system ID is enabled
Portfast Default is disabled
Portfast Edge BPDU Guard Default is disabled
Portfast Edge BPDU Filter Default is disabled
Loopguard Default is disabled
PVST Simulation Default is enabled but inactive in rapid-pvst mode
Bridge Assurance is enabled
UplinkFast is disabled
BackboneFast is disabled
Configured Pathcost method used is short

Name Blocking Listening Learning Forwarding STP Active
---------------------- -------- --------- -------- ---------- ----------
VLAN0001 0 0 0 1 1
VLAN0095 0 0 0 1 1
VLAN0108 0 0 0 3 3
VLAN0163 0 0 0 3 3
---------------------- -------- --------- -------- ---------- ----------
4 vlans 0 0 0 8 8

 

Trunk port

switchport trunk allowed vlan 1,95,108,163,203
switchport mode trunk
switchport nonegotiate

 

Any help would be appreciated on figuring out why the vlan isn't showing up.

 

 

 

 

9 Replies 9

Martin L
VIP
VIP

 

add missing vlan into vlan database with vlan x under config term (global config mode)

 

Regards, ML
**Please Rate All Helpful Responses **

Vlan isn't missing as shown with the show vlan brief command. Also can't add a vlan to a switch that is running VTP in client mode

 

VLAN0203 ?  is that "missing" vlan on other switch?  other end of trunk ?  For STP to be enabled and shown on vlan x , you must have 2 switches running that vlan and that vlan must be in vlan database on both switches and allowed over the trunk link. 

 

Regards, ML
**Please Rate All Helpful Responses **

 

 

 

Yes that vlan exists on both switches. 

 

Other switch

show vlan brief

203 VLAN0203 active

 

show spanning-tree summary

Switch is in pvst mode
Root bridge for: none
Extended system ID is enabled
Portfast Default is disabled
PortFast BPDU Guard Default is disabled
Portfast BPDU Filter Default is disabled
Loopguard Default is disabled
EtherChannel misconfig guard is enabled
UplinkFast is disabled
BackboneFast is disabled
Configured Pathcost method used is short

Name Blocking Listening Learning Forwarding STP Active
---------------------- -------- --------- -------- ---------- ----------
VLAN0001 0 0 0 2 2
VLAN0095 0 0 0 2 2
VLAN0108 0 0 0 6 6
VLAN0163 0 0 0 2 2
VLAN0203 0 0 0 2 2
---------------------- -------- --------- -------- ---------- ----------
5 vlans 0 0 0 14 14

 

as you can see the vlan is there and it is in the spanning-tree on the other switch.

Also here is the trunk on the other switch as well.

switchport trunk allowed vlan 1,95,108,163,203
switchport mode trunk
switchport nonegotiate

Hello
Fyi - there will be no stp for a vlan unless the vlan is in a active state, be on an active access-port or within an active trunk.


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

mlund
Level 7
Level 7

Hi

As the vlan is active but no spanning-tree on it, there may be a configuration like "no spanning-tree 203" or similar.

Try to enable with "spanning-tree vlan 203" the syntax may be different.

/Mikael

_|brt.drml|_
Level 1
Level 1

Verify if the VLAN has an active interface in it. 

 

rwills
Level 1
Level 1

I found the issue.  There was a vlan that was on one switch but missing on the other, causing a parameter inconsistency.  I had actually found that and fixed it, and bounced the ports, before posting.  But apparently another full reboot was needed to force it to discover that the parameters had been fixed.

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