OTV and Layer 2 Trunk - Together during migration ?

[Rajagopal Sivaramakrishnan]

Hi All

Existing DCI is a Layer 2 trunk, and we already built the OTV stretch parallel. There are many prod VLANs in L2 trunk which were extended before. Is it OK to have both OTV stretch and L2 , allowing these VLANs, to have a smooth migration ? Will there be loops because of 2 Layer 2 stretches between DCs ? I know OTV doesnt forward STP broadcasts, but are there any other design considerations that I should be aware of ?

Plan:

VLAN 10-20 PROD is in L2 trunk now

Deploy OTV and add VLAN10-20 in OTV

Remove VLAN 10-20 , one by one on L2 trunk, and fully migrate to OTV

Please let me know your thoughts ?  Thanks in Advance. 

[shaps]

You could be in a posistion where a loop is created,  there is a section in the below document detailing how to mitigate this

https://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Data_Center/DCI/whitepaper/DCI3_OTV_Intro/DCI_1.html

[Rajagopal Sivaramakrishnan]

Thanks for the quick response, and forwarding a good document.. This looks more complicated, as we have already built OTV with 2 different Site identifiers and Site VLAN.. :( 

and even with this solution, there is a convergence window - which will be similar to us disabling a VLAN in L2 and enabling in OTV.  Right ? 

"Disable the traditional Layer 2 extension solution. This will cause the OTV devices to lose the internal adjacency established via the site VLAN and to detect a "site partition" scenario. After a short convergence window where Layer 2 traffic between sites is briefly dropped, VLANs will start being extended only via the OTV overlay. It is worth noticing that at this point each edge device will assume the AED role for all the extended VLANs."