Ending a metroethernet link on a Catalyst 6500

IgorHamzic · ‎02-07-2008

Hi all.A service provider has connected two of our offices in a city with a metroethernet line and has sent that the line between the two offices is in VLAN X on their switches at both locations. I will be connecting the line on one end to a 6500 switch and the other side of the link on a 1840 router.

The thing that's a bit puzzling is the 6500 side.

I know a can assign an IP address directly to a fast ethernet port, connect a cable to the port assigned by the provider on their switch and it should work.

But I was thinking of doing something else.I was thinking of creating a VLAN X on the 6500 and assigning the IP address to the VLAN X interface so it can connect to the other office(X being the same number on both devices as I think they should be the same).

Would something like option 2 work? And if both options are viable which one would be better? Any help is greatly appreciated.

dgoodridge · ‎02-07-2008

Hi Igor,

Option two will work and in my opinion is actually the preferred design.

The only thing you need to figure out is if the end-to-end link is a trunk link or an access link. If you are looking to trunk multiple VLANS to the router then both ends need to be set to trunk mode and sub-interfaces need to be created on the router. This will only work if the service provider has specifically set each intermediate L2 link as trunks.

Alternatively to just enable simple connectivity then setup both ends as access ports using suitable IP addresses. I would still assign the IP address to the VLAN on the 6500 however the VLAN number can be anything you like (i.e. doesn't have to be the same as service provider) as the end-to-end link is Layer3 rather than Layer2.

Hope that makes sense.

Doug

IgorHamzic · ‎02-07-2008

Hi Doug,

Thanks for the fast reply. I was also leaning towards option 2 but wanted to be sure if it could be done.

I think the ports on the provider's switches on which I will connect 6500 and 1840 routers are access links as they have said they are only allowing VLAN X on the ports.

I didn't know that I could assign a different VLAN ID though so thanks for that great tip also.

I'll go configure the VLAN and VLAN interface IP address on the 6500 and configure the IP address on the 1840 router that will go to other office.

Igor