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Interconnecting two 3560 on different VTP domains

dapogsdapogs
Level 1
Level 1

I am having problems with my L3SW (model 3560). My L3SW have EIGRP running on it. Now, we are interconnecting with a vendor who is also using a 3560. I have no control on the vendor's 3560 whatsoever. The only information I have is the vendor's L3SW IP address, which is 192.168.11.131.

To enable the interconnection, I configured a VLAN on my side (VLAN11) and assigned an IP address to it (192.168.11.250). I then configured the port on my L3SW to which we are interconnected this way:

interface GigabitEthernet0/21

  switchport access vlan 11

After I have enabled the port, it took only 15 - 20 minutes before I lost connection to my switch. When I was able to get inside the switch and undo all the configurations and reload the switch, I found this error:

%DTP-5-DOMAINMISMATCH: Unable to perform trunk negotia
tion on port Gi0/6 because of VTP domain mismatch

It seems that the trunking was broken on my L3SW when I enabled the interconnection port. Please let me know of a better way to handle this.

1 Accepted Solution

Accepted Solutions

Reza Sharifi
Hall of Fame
Hall of Fame

Hi,

Does the connection have to be in a vlan? You can just make gi0/21 a routed port by using the command "no switchport" and then assign the IP address directly to the physical interface and then add the network to the EIGRP process.   BTW, any idea how the other site is configured?

HTH

Reza

View solution in original post

4 Replies 4

Jon Marshall
Hall of Fame
Hall of Fame

dapogsdapogs wrote:

I am having problems with my L3SW (model 3560). My L3SW have EIGRP running on it. Now, we are interconnecting with a vendor who is also using a 3560. I have no control on the vendor's 3560 whatsoever. The only information I have is the vendor's L3SW IP address, which is 192.168.11.131.

To enable the interconnection, I configured a VLAN on my side (VLAN11) and assigned an IP address to it (192.168.11.250). I then configured the port on my L3SW to which we are interconnected this way:

interface GigabitEthernet0/21

  switchport access vlan 11

After I have enabled the port, it took only 15 - 20 minutes before I lost connection to my switch. When I was able to get inside the switch and undo all the configurations and reload the switch, I found this error:

%DTP-5-DOMAINMISMATCH: Unable to perform trunk negotia
tion on port Gi0/6 because of VTP domain mismatch

It seems that the trunking was broken on my L3SW when I enabled the interconnection port. Please let me know of a better way to handle this.

The DTP error message is talking about gi0/6 yet you configured gi0/21 as an access port for the connection. Can you clarify.

In answer to the general question if you are connecting 2 switches with a link and they are in different VTP domains you need to disable DTP ie. under your interface configuration -

int gi

switchport nonegotiate

Jon

Hi Jon,

The trunking on my switch was broken actually. It broke the trunking for all the ports, including the interconnection port. So basically I lost everything on that L3SW when I activated the interconnection port.

Reza Sharifi
Hall of Fame
Hall of Fame

Hi,

Does the connection have to be in a vlan? You can just make gi0/21 a routed port by using the command "no switchport" and then assign the IP address directly to the physical interface and then add the network to the EIGRP process.   BTW, any idea how the other site is configured?

HTH

Reza

Thanks Reza. I will give a try to the routed port option tonight and w

ill let you know by tomorrow if it works. ^_^

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