10-02-2013 09:47 AM - edited 03-07-2019 03:48 PM
Hello,
I am facing an issue on one of my remote office on which the lan is switch is not the root bridge and in these delegations there are facing slow performance on which I m currently investigating.
after a simple diff between the config of some others remote offices and this particulare one I foud out that the switch is not the root bridge
DELXXXXsw001#show spanning-tree
VLAN0001 Spanning tree enabled protocol ieee
Root ID
Priority 32768
Address 0012.a934.36e0
Cost 4
Port 21 (GigabitEthernet0/21)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1) Address 001e.f6c1.0700 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/1 Desg FWD 19 128.1 P2p
Gi0/2 Desg FWD 19 128.2 P2p Edge
Gi0/3 Desg FWD 4 128.3 P2p Edge
Gi0/4 Desg FWD 19 128.4 P2p Edge
Gi0/5 Desg FWD 4 128.5 P2p Edge
Gi0/6 Desg FWD 19 128.6 P2p Edge
Gi0/7 Desg FWD 4 128.7 P2p Edge Interface
Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/8 Desg FWD 19 128.8 P2p Edge
Gi0/16 Desg FWD 19 128.16 P2p Edge
Gi0/17 Desg FWD 4 128.17 P2p Edge
Gi0/20 Desg FWD 19 128.20 Shr Edge
Gi0/21 Root FWD 4 128.21 P2p
On this remote office they have plugged an ub or another exotic switch that seems to take the control of the spanning tree
However why I can see it on when I do a show mac add
e.g.
show mac add | i 0012.0a934.36e0
also can I just take the control of the spt by using the command
(config) t spann vlan X root primary???
thanks a lot
10-02-2013 10:12 AM
Personally, I'd change the priority to 0 for your vlan:
spanning-tree vlan X priority 0
HTH,
John
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10-02-2013 10:21 AM
You should probably also shut down interface g0/21. If someone has connected another switch that you don't control or know about, it should be disabled.
10-02-2013 10:30 AM
Gents,
Thanks for your answers. However how to find this mac? I m sure it's coming from the port 21 (I see it on the show span output)
DELXXXXsw001#show spanning-tree
VLAN0001 Spanning tree enabled protocol ieee
Root ID
Priority 32768
Address 0012.a934.36e0
Please help
Kar
10-02-2013 10:33 AM
sh mac address gig0/21 should give you all MAC addresses the switch sees on that interface.
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