Vtp between 2 Catalyst switches across a router

Unanswered Question
Feb 7th, 2007

I have in my domain :

C3750 ---.1Q G0/1---C2821 ISR---.1Q G0/2 --- C2950

C3750 is in vtp server mode

C2821 is in vtp transparent mode

C2950 is in vtp client mode

Will my vlans be distributed from C3750 to C2950 across ?

I have this problem too.
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andreas.larsen@... Thu, 02/08/2007 - 00:00

I guess you have a routed interface or something in between the C3750 and C2950. If that is the case then the VTP it's not shared inbetween. You could however connect the C3750 and C2950 with a fibre or something and run a trunk over that get the VTP to cross.

Please rate if you find it usefull.

falain Fri, 02/09/2007 - 13:24


Thanks for reply.

I thought that VTP could be forwarded across c2821 but it doesn't work like a switch/router such as C3750 in vtp transparent mode.

I suppose that C2821 has not the same switching backplane architecture than C3750.

I put a trunk link cable between c3750 and c2924

and set both in the same vtp domain.

Then now I get all my level 2 vlans on C2924, but they can be routed at IP level by C2821 or C3750.

Jitez1234 Thu, 02/08/2007 - 02:57

Vlans will be propergated from server to client mode and transparent mode,however transparent mode will only forward the vlan infos and will not process them, so you will not see the vlans in the c2821.

All switches should be Linked by a trunk configuration.Then ensure they are all in the same vtp domain. The C3750 is capable of inter vlan routing.

scheikhnajib Thu, 02/22/2007 - 06:47

I think the whole VTP support on the 2821 is for you to use the switch network modules and in this case your ISR router will be a router + a switch but I don't see it working on the onboard Ethernet interfaces.




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