NSX-T 3.1 Multi-site question

[Petersaints]

Hello all,

I'm deploying a multi-site environment. I have the management vlan stretched between the two sites.

I have a doubt about the TEP pools,  that is:

On site A i have VLAN 10 for host TEP and VLAN 11 for edge TEP.

On site B i have VLAN 12 for host TEP and VLAN 13 for edge TEP.

When i join the edges of the Site B to the stretched edge cluster, all the tunnels are down. Why does it happen?

Should host and edge TEP VLANs be stretched on both sites too, or if i choose not stretch the vlans, all of them must communicate between each others?

Thanks.

Regards.

[CyberNils]

Hi,

All the TEPs need to communicate with each other, so they need to be routed on an external router. MTU must me at least 1600. If you are unable to route them for some reason, you can put all the TEPs in the same VLAN.

[Petersaints]

Hi @CyberNils ,

Thanks for the answer.

Even on the multi-site scenario, right? I have read the multi-site design guide and the only mention to stretched networks, was the management vlan. 

Or the correct approach is stretch the TEP vlans also, if possible?

Thanks!

Regards.

[CyberNils · Accepted solution]

Management VLAN is stretched so that vCenter can fail over to the other site. If you want your NSX Edges to fail over to the other site, you also need to stretch the Edge TEP VLAN. If you have dedicated Edge VMs in each site, you don't need to stretch the Edge TEP VLAN, but then you need to route between them on an external router.