OTV

[happyatuni]

Dear All,

I have 2 DataCentre (one primary and one backup) across 2 states.  My VMWare guys wants to do VMotions between the 2 x Data Centres.  But I wouldn't be able to bridge 2 x Data Centres with Dark Fibre (too far of a distance).

How does OTV work? Does it encapsulates L2 information within L3 connections?

Would be greatly appreciated if anyone can shed some lights on this.

Cheers,

Hunt

[David Lucas]

Hello Hunt!

This can be a loaded question. I'll start by answering your question and we'll take it from there.

In a OTV network, there are three main interfaces.

Internal interface - this is the interface that participates in L2 and extends the network. This interface can be a access or trunk port. It should be mentioned that this interface participates in Layer 2 so normal STP considerations need to be taken.

Join interface - this is the interface where L2 is encapsulated into L3. This interface has an IP address assigned to it and uses IGMP to join the OTV multicast group. OTV adds a 42 byte header to the packet so consideration for that need to be taken as well.

Overlay interface - this is a virtual interface where OTV configuration is applied.

As I said this can be a loaded question and I only touched on the interface. To answer you question:

"Does it encapsulates L2 information within L3 connections?"

Yes, at the join interface.

Hope this helps.

Dave

[amandes2]

Hello Hunt,

Just to add up on David's reply above.

You can find the complete documentation on configuring OTV here :

http://www.cisco.com/en/US/docs/ios-xml/ios/wan_otv/configuration/xe-3s/wan-otv-confg.html

Hope this helps

[jkilleda]

Hello Hunt,

OTV

OTV is a technology which is used to extent existing L2 infrastruture over L3 netwrok , which is supported by Nexus 7k and ASR router only. You need to have transport service license on NX-OS inorder to deploy OTV