cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
Announcements

Community Helping Community

144
Views
5
Helpful
3
Replies
Enthusiast

spanning-tree root question

Hello all,

 

we have the attached topology (two nexus 5K) on two sites, which are connected via trunk links. On the Nexus we also have connected devices which perform bridging (IPS/Imperva).

When running the "show spanning-tree root" command on any of the devices I get the following for the bridged vlans:

Site-1(1)# sh spanning-tree root

Root Hello Max Fwd
Vlan Root ID Cost Time Age Dly Root Port
---------------- -------------------- ------- ----- --- --- ----------------

VLAN0040 40 0023.04ee.be0a 0 2 20 15 This bridge is root
VLAN0041 40 0023.04ee.be0a 21000 2 20 15 port-channel1
VLAN0070 70 0023.04ee.be0a 0 2 20 15 This bridge is root
VLAN0071 70 0023.04ee.be0a 21000 2 20 15 port-channel1
VLAN0080 80 0023.04ee.be0a 0 2 20 15 This bridge is root
VLAN0081 80 0023.04ee.be0a 21000 2 20 15 port-channel1
VLAN0090 90 0023.04ee.be0a 0 2 20 15 This bridge is root
VLAN0091 90 0023.04ee.be0a 21000 2 20 15 port-channel1
VLAN0131 131 0023.04ee.be0a 0 2 20 15 This bridge is root
VLAN0132 131 0023.04ee.be0a 21000 2 20 15 port-channel1

 

Lets say that 70/71 are bridged. Under the Root ID column I only see vlan 70, even when viewing the root for vlan 71. What is this number "70" referring to? Is it normal to see this output when bridging is also in place?

 

Thanks in advance,

Katerina

1 ACCEPTED SOLUTION

Accepted Solutions
Collaborator

Re: spanning-tree root question

Great... mark as solved if possible, it will be used to an other cases.
Jaderson Pessoa
*** Rate All Helpful Responses ***

View solution in original post

3 REPLIES 3
Collaborator

Re: spanning-tree root question

hello

 

 

show spanning-root 

VLAN0302 302 700b.4f26.5a80 0 2 20 15

 

show spanning vlan 302

 

Bridge ID Priority 302 (priority 0 sys-id-ext 302)

 

this information is "sys-id-ext 302"

 

that is used to root election process in case of the same numbers in whole process.

Jaderson Pessoa
*** Rate All Helpful Responses ***
Enthusiast

Re: spanning-tree root question

Ok! Got it! I have never noticed it before and since the vlans in question are bridged it makes sense.

 

Thanks!

Collaborator

Re: spanning-tree root question

Great... mark as solved if possible, it will be used to an other cases.
Jaderson Pessoa
*** Rate All Helpful Responses ***

View solution in original post

CreatePlease to create content
Content for Community-Ad