What is requirement for inter-connect network (device) for cisco OTV?

[Herman2018]

hi, we want to setup OTV between two data centers with using nexus 7k. However, the inter-DC circuits are terminated on other devices. The simple diagram is shown as below. What is the requirement for this network devices (other layer 3 switch in the diagram below) ? can someone please advise, thanks in advance.

[balaji.bandi]

You need to extend that VLAN

below example - 

https://www.cisco.com/c/en/us/support/docs/routers/asr-1000-series-aggregation-services-routers/117158-configure-otv-00.html

https://www.cisco.com/c/en/us/support/docs/routers/asr-1000-series-aggregation-services-routers/117157-configure-otv-00.html