Question about trunking modes compatibility

yuriz43

I have a question about vlan trunking in regards to how switches in different management domains, and ones in transparent mode would work together.

Simply, consider the following scenario

2 switches are configured as server mode, in the vtp domain Test, with a vtp password of cisco.

1 switch is configured as transparent mode, with no vtp domain or password.

All 3 switches are trunked together in a circle.

You create vlan id 5 on the 2 switches which are in the same management domain, and you manually add vlan id 5 to the transparent mode switch.


Will the transparent mode switch be able to communicate with the other 2 switches on vlan id 5, or any other common vlan id between them?

kryolla

For DTP to work your domain has to match between all switches. Just hard code dot1q and mode trunk

yuriz43

Ok, so if I force all the trunk interfaces as 'switchport mode trunk' the vlan traffic in vlan id 5 will be passed, even if the transparent mode switch is in the null management domain??

kryolla

yes as long as spanning tree is forawding the traffic.

GT-Rob

yes you can still make the trunk, its DTP that won't run if they are in different domains.