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VLAN routing on Catalyst plus external WAN router issue......


Bit of advice if possible.

I've got a project to implement VLAN's on a MAN, which is easy enough, using CAT4506 and a mixture of 3750 and 2950 switches. The Vlan aspect is OK but I'm a bit unsure as to how to integrate the WAN into the design.

I have two core WAN access sites each with 2 * cat4506 switches of which one at each site attach to a WAN router (3725)

The CAT4506 switches will be doing the vlan routing but the 3725 routers (one at each site in a HSRP group) will be routing the WAN. Obviously these need to be attached to the catalysts for WAN access. As I have seperate routers for vlan routing and wan routing, what is the best way to configure this ?????

Is configuring a seperate VLAN for the routers the best idea ? or is it best to use the sub interface option on the router ethernet ports ?

Do I just use a static route of last resort on the Catalyst pointing to the routers ?

Help :-)


Re: VLAN routing on Catalyst plus external WAN router issue.....

When you arte still in the design-phase, I want to strongly discourage you from designing a network with vlans that span multiple sites.

You will always run int STP issues in one way or another. The following link will give some sensible information on this subject:

I hope that it will point you to the right (or at leats an optimal) solution for your specific design.



New Member

Re: VLAN routing on Catalyst plus external WAN router issue.....

Yes true, the vlans are only buildings wide not MAN wide. The main problem is the integration of the routers and layer 3 switches.

Thanksfor the help though.

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