Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

L2 between seperate VTP domains


I am trying to configure our 6506 to communicate with a separate network. Currently we use STP MST and have a vtp server configured. I just added a 3550, but it needs to be on a different vtp domain. My real problem is that my current network has a vlan with the network assigned to it. The new network needs to use a network. I can't create a layer 3 interface because the network is assigned to the VLAN. Can this be set up via L2 and non-routed or private VLAN's. Does anyone have any experience with anything like this?

Thanks in advance.


Re: L2 between seperate VTP domains

No, I don't think you can.

At layer two, everything is Ethernet (MAC) ... there's no manipulation of an IP (or any other network-level) address.

Best case that I can think of would be a NAT, but that's still a layer three+ issue.

IMHO, you'll need to do some re-addressing at one place or another, in the meantime, maybe a router using SECONDARY addressing on the ambiguous interface. BEcareful though, SECONDARY addressing can cause some "issues" with some routing protocols (like spilt horizon problems).

Good Luck


New Member

Re: L2 between seperate VTP domains

I have a router I can use, but I would like to keep the latency as low as possible because the data will primarily be streaming medical images.

Would a bridge interface on the router (2821) help alleviate latency or should I set this up as standard interfaces? BTW, I have two gig fiber interfaces.

New Member

Re: L2 between seperate VTP domains

Would it not be possible to set this up with trunk ports on each side and then use Switchport trunk allowed vlan xxx-xxxx to achieve the same effect as a routed link?

CreatePlease login to create content