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Bridging a VLAN across two cores (L3 switches)

oneirishpollack
Level 1
Level 1

Hi All,

 

I have a 6509 that is the L3 for one building and a 4900 that is the L3 for another building.

I have 3 VLANs on each core in each building:

 

VLAN 2 test

VLAN 3 staff

VLAN 4 guest

 

Each of the VLANs is actually managed by the respective L3 switch that has the SVI for it. Each of the cores use the same VLAN IDs, but with a different VTP domain.

 

However, I have established a need for a VLAN that is on the 6509, but bridges across (or through?) the 4900 for my wireless VoIP. All I want the 4900 to do is pass the L2 traffic from the 6509 to devices that exist on the new VLAN (725). 

 

What is the best way to do this? 

 

 

 

2 Accepted Solutions

Accepted Solutions

Rajeev Sharma
Cisco Employee
Cisco Employee

Hey,

Just create the vlan only and make sure its allowed on the incoming and exit trunk links.

HTH.

Regards,

RS.

View solution in original post

Hi,

You just need to configure the trunk interfaces on the cores as follows:

 

switchport mode trunk,

switchport nonegotiate.

 

That will now ignore the vtp domain mismatch.

 

Cheers

 

 

View solution in original post

5 Replies 5

Rajeev Sharma
Cisco Employee
Cisco Employee

Hey,

Just create the vlan only and make sure its allowed on the incoming and exit trunk links.

HTH.

Regards,

RS.

I created the VLAN (725), however the trunk between the two cores gives me a VTP domain mismatch error.

The two core are different VTP domains. I did recently set both the cores to Transparent mode.

However, I am still getting a domain mismatch. In transparent mode, can I safely remove the domain names at this point?

 

 

 

 

 

 

 

 

 

Hi,

You just need to configure the trunk interfaces on the cores as follows:

 

switchport mode trunk,

switchport nonegotiate.

 

That will now ignore the vtp domain mismatch.

 

Cheers

 

 

So quick question, 

 

If I put my cores both back into VTP server mode - will they still only manage their respective domains? There is no change, regardless of revision # that a vlan.dat can be over written by the other VTP server if they are on different domains, correct?

Hey,

You are correct, they will be managing there respective VTP domains. And will not overwrite the vlan.dat file.

Regards,

RS.

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