Trunked vlan allowed but not active or in spanning tree

[tacit.cheddar]

VLANS trunks doesn't work 

I created Vlans 10,20,30,40 on switch1. I am trying to trunk them to switch2.

I used the following commands to add vlans to trunk interface on switch1:

     Switch(config)#int g1/0/2

     Siwtch(config-if)#switchport trunk allowed vlan 10-40

     Command #show int trunk   

            Says vlans allowed on trunk interface: 10,20,30,40 

            Says vlans allowed and active in management domain: 10,20,30,40

            Says vlans in spanning tree forwarding state and not pruned: 10,20,30,40

I used the following commands to add the vlans to trunk interface on switch2   

    Switch(config)#int g0/1

    Siwtch(config-if)#switchport trunk allowed vlan 10-40

   Command #show int trunk

         Says vlans allowed on trunk are 10-40 

         Says vlans allowed and active in management domain: 10

         Says vlans in spanning tree forwarding state and not pruned: 10

Can anyone tell me why vlan 10 is the only vlan showing up as allowed, active in management domain and spanning tree forwarding state? How do I get the other vlans to show up as active and in the spanning tree forwarding state? thanks!!

[Jaderson Pessoa · Accepted solution]

Hello my friend..

trunking vlan doenst means that you i've created the vlan layer 2 itself.

i think you need create vlan first.

try create it..

conf t:

vlan 10

vlan 20

vlan 30

etc.

thank you

[Giuseppe Larosa · Accepted solution]

Hello @tacit.cheddar ,

as noted by @Jaderson Pessoa likely vlans 20,30,40 are missing from vlan database on switch 2.

even if we can create a Vlan "on the fly" by  using

interface gi1/0/5

switchport

switchport mode access

switchport access vlan X

this is not true for trunk ports as you need to manually create the missing VLANs on switch2

conf t

vlan 20

name VLAN20

exit

vlan 30

name VLAN30

exit

vlan 40

name VLAN40

exit

compare the two VLAN databases using

show vlan

show spanning-tree summaty on both switches

Hope to help

Giuseppe

[tacit.cheddar]

Thank you all for the replies... I must have done something wrong when I originally created the same vlans on both switches.... but I re-did it and it worked! so thank you all again!

[Georg Pauwen]

Hello,

on a side note, in order to make sure that the Vlan databases on switches are synchronized, typically VTP is being used. The configs for both switches would be:

Switch 1

Switch_1#conf t
Switch_1(config)#vtp domain yourdomain
Switch_1(config)#vtp mode server
Switch_1(config)#vtp password yourpassword
Switch_1(config)#vtp version 2

Switch 2

Switch_2#conf t
Switch_2(config)#vtp domain yourdomain
Switch_2(config)#vtp mode client
Switch_2(config)#vtp password yourpassword
Switch_2(config)#vtp version 2