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Cisco 3750 stack switch between multiple buildings route as distribution layer to core with multiple distribution layers routed

I have multiple buildings and would like to route at the distribution layer from each building. I have two stacked 3750 switches at each building for redundancy. There is fiber between each building. Total of three buildings. We will call them building 1, 2 , and 3. Building 3 has the distribution switch that goes through building 2 via Fiber. Building 2 traffic is aggregated with building 3 traffic which eventually makes it to the core at building 1. This is the Fiber layout. The buildings are close together. I need to route from building 3 to building 2. The access layer switches are 3com with no Vlan support they will just connect to the distribution switches. Then I want to route the traffic from there. I am not sure about layer 3 design routing with multiple Vlan's that represent subnets. How do you get the routing to go from one end say building 3 to building 2 and then to building 3 and visa versa. Say I use 10.0.1.x through 10.0.10.x at a class C subnet mask. Could I create all static routes between the stacked switches? But if I have more than one subnet on a switch how do you route traffic between the two. The master 3750 switch in the stack acts as a single router as far as the mac address is concerned. So I think for every IP addres default gateway per subnet it will us the mac address with the different default gateway. For example; 10.0.1.1 and 10.0.;2.1 and on the other side would I setup the same vlans and different IP address combinations? For example 10.0.1.2 and 10.0.2.2. If I have two fiber connections between the stacked switches how does routing work?

MikeKane

If you want to isolate broadcast traffic from each building, then, depending on your specific needs, you would create a VLAN to represent each logical network. From what I understand each building would be a VLAN. On each switch you would create the VLAN and since you have a Fiber uplink between the buildings, you would use the FIBER as your tunking port between the switches. You can then route using static commands, or EIGRP between each VLAN point.

You can use one single master switch if you want to use statics routing.... it would work, especially if the one uplinks all the other fiber leads....

Hope that helps.

asmusjer1

ASKER

I am confused about the specifics of setting up the routes. For example if each switch represented two vlans with a 3750 switch then you need two static routes. A stack design makes it complex because you need to route each vlan in some form. That is if you routed from the distribution layer at each building. You really can't use a default route or an ip default gateway between the two seperate distribution switch racks because again two many routes. Maybe a need to look at this like a router with multiple network cards. You would have to setup each Vlan on all of the switches with the routing but the default gateway routes would be different on each switch stack for the vlans.
I guess I am confused with Routing when redundancy comes into play. If I could get a traditional routing example maybe with multiple ethernet cards per each router. Then corolate this to 3750 stack switch design. Not sure if any one can help.

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MikeKane

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