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CWDM Question

To to pick your brain i have 2 pairs of dark fibers between two datacenters. Dark fibers are terminating on 8 Port channel CWDM and have two pairs of catalyst 6509 switches connecting to the CWDM using 2 channels each at each datacenters. The connection between the 6509's via CWDM are Layer 3 routing usinf EIGRP. I would like to also have a layer 2 connecting between the datacenters since i have few spare channels on the CWDM for server clustering ( two servers between DC need to be on same subnet) and don't want to encounter any STP issues between the 6509 switches. How can i achieve this?

My idea:

Dont have any layer 2 connection on the 6500's since they are core and connect another pairs of Catalyst 4507 at each datacenter to the spare channels on the CWDM and have a layer 2 trunk between the datacenters from the catalyst 4507 acting as a distribution switches passing frames between the two servers via layer 2 for vlan 95 and have the 4507 connect to the Core 6509 via layer 3 routing. So the cat catalyst 4707 will act as a distribution and access.

will my idea work?


Hall of Fame Super Blue

Re: CWDM Question


At a high level i cannot see why this wouldn't work although perhaps you may consider eiher 3750-E or 4948 switches rather than the 4500 switch which seems slight overkill for forming a separate L2 link.

You don't say what function your 6500's serve but assuming they are core within your DC's i would support separate switches for L2 connectivty if you can afford it.



Cisco Employee

Re: CWDM Question


For high availability and redundancy, consider two pairs of CAT 6500s with VSS on each DC. Use multi-chassis etherchannel on the CWDM links between the VSS switches. No STP what so ever.