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Routing Between Switches

Location 1 has 10 layer 2 switches. Location 2 has 6 layer 2 switches. Location 3 has 8 layer 2 switches.

Location 1 has VLAN1 and VLAN2. Location 2 has VLAN2 and VLAN3. Location 3 had VLAN2 and VLAN4.

Each VLAN is in its own subnet.

There is a 3750 at each location. I want to do intervlan routing so workstations can connect across vlans at all locations.

Is this possible if I use IP Routing on all 3750 switches and if so, how are the trunks configured? Also, must the be ip addresses for all vlans on all switches or just for the vlans with corresponding subnets?

Thanks,
Oz

Les Moore

Are all switches connected by fiber between locations?
With the 3750, you have an option to create a single switch stack. They don't have to be physically stacked, just logically. Then they all appear as just one switch with multiple "blades". Only one IP address, only one L3 vlan interface per vlan. Think of it as a single switch. Depending on the model of L3 switches, you may be able to add them to the same stack.
If you want to keep them distributed, make one the router for VLAN 1&2, another for VLAN 2&3, and another for VLAN4

If you "stack" them, then you don't have to worry about trunking or anything...

cisdoz2

ASKER

If the switches aren't physically stacked, wouldn't they be considered a cluster instead of a stack?

Les Moore

Clusters are managed from one IP address with web interface, but still are independent of each other.
The 3750's have a different stacking technology rather than just the cluster management suite..
It's been a few months since I've played around with the 3750's, and I am getting old and gray and braincells are going awol on me, so I could be rusty.. You may have to use the stacking cables with them to put them in a stack, but I'm not sure....
Hmmm.. need ... more .... coffee....

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cisdoz2

ASKER

Thanks Doc,
After considering the possibilities, I will configure each switch to do routing for its paticular campus to avoid the single point of failure scenario.

Dr-IP

Not taking in account of possible failures is one of the most common mistakes I see in designing networks. I know it’s not always practical to create a fully fault tolerant network, but you can usually minimize the impact of failures. I always think of what is the worst thing that could happen, and take it from there. Sometimes it makes for more work on the administrative side, but over the years it has served me well, as most years my network delivers five nines reliability. So keep in mind, if you can conceive of something going wrong, if you don’t plan contingences for it, it’s almost assured to happen to you.