OTV without VDC

[efirestone]

We currently have 4 7Ks in out main data center and would like to configure OTV to extend vlans between cores 3 and 4 without purchasing the VDC license.  We were under the impression that we would be able to trunk vlans from cores 3 and 4 to 1 and 2 while configuring OTV between cores 1 and 2.  My concern with this is how traffic would be routed between the cores.  We already have layer 3 links between the cores so would traffic use the layer 2 trunk or be routed layer 3?

I have attached a visio of the current layout.

[phiharri]

Hey Eric,

I'm a little confused as to why you want to run OTV between devices in the same physical datacenter! OTV is intended for extending Layer 2 between sites/datacenters which typically means - physically separate and cannot be connected directly at L2.

As mentioned in the configuration guide, the OTV edge device/VDC cannot also be a gateway for VLANs transported on the overlay, hence the common designation of a VDC for OTV purposes with a physical loopback to the VDC with SVIs. Moving all SVIs off the Nexus 7000s would be the only way OTV can function in your topology without the VDC license.

The following page links several documents which explain in detail OTV and typical topologies:

http://www.cisco.com/en/US/docs/switches/datacenter/sw/nx-os/OTV/roadmap/Nexus_7000_otv_roadmap.html

Hope this helps!

/Phil

[efirestone]

I would really prefer not to implement this for communication within the data center.  I would much rather run VPCs from cores 3 & 4 to 3750s and have the vm servers connect there.  Using OTV is something my manager would like to use, but I dont think he fully understands the complications with such a setup within the same data center especially since we dont have the VDC license for any of the cores.

I really dont even know if it will work no matter how we set it up since trunking vlans up to core 1 from core 3 will cause routing issues with traffic trying to reach core 3 via core 1 on any vlans that we have trunked.