Stretching VLAN

[Anwar Safian]

Hi expert

There are lot of information about how could we stretch VLAN including L2TPv3, VPLS, OTV etc.

However, why do we need to stretch the VLAN? Why dont we just use normal layer 3 routing to send traffic?

Any example/case of using stretching VLAN?

[Francesco Molino]

Hi

It depends on your architecture and application designs/redundancy.

For example, in datacenters, some customers will have a VM running on 1 site and if this site goes down, they want the duplicate vm on site 2 to take over using same IP. In that case you'll need to have a 'Layer 2' continuity no matter the technology (l2tpv3, otv, vxlan....)

This is 1 of many use cases.