Should I use Cisco OTV for the Datacenter Interconnect ?
Should I use Cisco OTV for the Datacenter Interconnect? This question comes from not only from my students but also the companies which I provide consultancy.
I will not go through the OTV details, how it works, design recommendations etc. But let me remind you what is OTV and why OTV is used , Where it makes sense very briefly.
OTV (Overlay Transport Virtualization) is a tunnelling mechanism which provides to carry Layer 2 ethernet frame in IP. (As I indicated in other articles, when I say MAC in IP, it is the same thing with MAC over IP).
So, OTV is Layer 2 in Layer 3 tunnelling mechanism. You can hear it is an encapsulation mechanism as well, which is true although there is small difference.
You don’t need to have MPLS underlay to create OTV tunnels. It uses IS-IS for the MAC address reachability and stops layer 2 protocol PDUs at the OTV Edge device where encapsulation happens.
This is good because, you don’t want to extend Layer 2 protocol PDUs such as Spanning Tree if you have multiple datacenters. Failure stays and affects only one datacenter, not all. (Failure domain boundary concept)
Another datacenter interconnect requirement Continue reading