[c-nsp] OTV overlay mac limitation ?

[Jeffrey G. Fitzwater]

We are looking at OTV to mainly eliminate the tromboning of packets between out two data centers which will soon both have 7013 nexus (only one 7018 the other a 6513 soon to be upgraded).

The two data centers each have many L3 subnets and are extended to the other data center using L2 trunks.

Problem Description:
	If host on subnet A (Data Center 1) wants to talk to a host on subnet B (same data center) and the L3 interfaces are at Data center 2, then all the packets between hosts on subnet A and B must travel to data center 2 and back again.

	We had thought that OTV would eliminate this problem but the mac address limitations for the OTV OVERLAY of 16K and the OTV EDGE limit of 4K stopped us in our tracks.   We currently have 30K macs at one data center which the other data center would need to have in its OTV FDB table and therefor over the limit of 16K.

	Either we don't understand OTV enough or we need to rethink things.


Q	Is there any OTV users out there that can confirm or correct me on this limit?

WE are also working with CISCO on this but are still trying to find the person with the answers.


We are also looking at LISP to solve this issue but that's another thing we don't know enough about.


Thanks for any help.




Jeff Fitzwater
OIT Network Systems
Princeton University