Cisco OTV Configuration/Q&A

[Saulbadguy]

Anyone here familiar with Cisco OTV?

I inherited an OTV configuration from a previous co-worker. While everything seems to be set up right, i've got some concerns.

1. When the OTV overlay is shut down, any OTV extended vlan can't communicate with any other non-OTV extended vlan in the other data center (I only have 2 data centers - 1 DCI/10gb link WAN link). Is that normal? For instance, VLAN 5(DC1 and DC2) is OTV extended, Vlan 10(DC2) is not. When the overlay is shut down, VLAN 5 can not communicate with Vlan 10.

2. All my interfaces in Data Center 2 are 10gb. My Wan link is 10gb. In data center 1 I have a 1gb layer 3 link. When I try to move it to a 10gb link, OTV starts flapping. Any reason why this would happen? I have all my MTU sizes set to 2000.

FYI Only: At both data centers I have the OTV join interfaces in a separate VDC and a layer 2 and a layer 3 link to the "core" vdc. Also using Unicast (no reason why, it was just set up that way).

 

[Cooky]

Cisco has published a few OTV design & config guides.
They're nicely written, w/ a ton of good info; try to read them over when you have time.

I did an OTV deployment years ago; everyone's network is different, but I believe shutting down the overlay interface shouldn't prevent VLAN5 from communicating w/ VLAN 10, assuming the routes are reachable from each other.
Are you saying VLAN5 hosts in DC2 cannot talk to hosts in VLAN10, also in DC2? Are the two VLAN's routed as SVI's on the same N7K?
If VLAN5 hosts in DC1 cannot talk to VLAN10 hosts in DC2, or a different L3 switch in DC1, you may have a routing/switching issue.

Moving a link from 1G to 10G shouldn't cause flapping.
MTU of 2000 should be ok, but I used 9216 in my previous deployment.