L2 and L3 VPN

[Hythim Ali El Hadad]

Hi,

I need to know the difference between L2 and L3 VPN

Also what OTV add to the VPN more than these ?

Thanks

[Joseph W. Doherty]

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Posting

I need to know the difference between L2 and L3 VPN

One provides layer 2, the other layer 3.  An example of the former would be l2tpv3 and an example of the latter, GRE.

Also what OTV add to the VPN more than these ?

It's an option on Cisco Nexus 7000s, for L2 VPN.  You can read more about it here: http://www.cisco.com/c/en/us/solutions/data-center-virtualization/overlay-transport-virtualization-otv/index.html

[Hythim Ali El Hadad]

Hi Joseph,

Thanks for your reply

I need to know the difference like when to use each and what is the most used for both and it'll be good if there is a document.

Also I know about OTV. but what it'll provide other than other L2 VPN methods

Thanks

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages wha2tsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

When to use either depends on your needs.  I don't know which is most often used, not sure anyone does.

I'm not familiar enough with OTV to know what it offers that's above-and-beyond other L2 VPN methods, but as Cisco has added it to the Nexus 7000s series, I would surmise it offers something "extra" or works "better" on a Nexus 7000 than other L2 VPN technologies.  (At the very least, it should help lock you into using the Cisco Nexus.)

[Hythim Ali El Hadad]

Thanks again Joseph

Wish someone could describe this clearly

[vivek srivastava]

You can refer below for more info on OTV. Below paragraph is a good extract about difference between OTV and L2 VPN

Extract

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OTV introduces the concept of "MAC routing," which means a control plane protocol is used to exchange MAC reachability information between network devices providing LAN extension functionality. This is a significant shift from Layer 2 switching that traditionally leverages data plane learning, and it is justified by the need to limit flooding of Layer 2 traffic across the transport infrastructure. As emphasized throughout this document, Layer 2 communications between sites resembles routing more than switching. If the destination MAC address information is unknown, then traffic is dropped (not flooded), preventing waste of precious bandwidth across the WAN.

Link - http://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Data_Center/DCI/whitepaper/DCI3_OTV_Intro.pdf