VXLAN Underlay

[syed.saaud]

Can we create a VXLAN underlay using VLAN interfaces instead of assigning IP-Address directly on the physical interfaces.

sp-i# sh ip int brief vrf all

IP Interface Status for VRF "VXLAN"(7)
Interface         IP Address            Interface Status
Vlan1800       10.18.16.225        protocol-up/link-up/admin-up
Po519.1809   10.18.16.209       protocol-up/link-up/admin-up

[Hector Gustavo Serrano Gutierrez]

Hi @syed.saaud,

You should only use Layer 3 ports (IP address assigned directly on the physical interface) for VXLAN underlay. This is Leaf-to-Spine connectivity in the Global Routing Table (vrf default) on the Nexus 9000 family of Switches running NX-OS.

Is there a reason you are looking for a different approach?

One more thing, you are showing a vrf called "VXLAN" which is ok for the vxlan overlay but not for the underlay.

On the other hand, if you have "bud node" topology, you can use SVIs. This scenario is when you have another VTEP behind the Nexus Leaf Switches in vrf default and the SVIs are the "uplinks" in the underlay.

Here the documentation for the "bud node" topology for your reference:

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus9000/sw/7-x/vxlan/configuration/guide/b_Cisco_Nexus_9000_Series_NX-OS_VXLAN_Configuration_Guide_7x/b_Cisco_Nexus_9000_Series_NX-OS_VXLAN_Configuration_Guide_7x_appendix_0101.html

Best Regards.

[syed.saaud]

Hello Hector,

Thanks for your reply.

The reasons for having a different setup is that, I have multiple Vlan-interfaces created on the links which are connected to Spine-Leaf in different VRF's. I don't want to change this.

Will it work if I want to create the underlay in the global routing table(default) using Vlan-interfaces?

Regards,

Syed Saaud

[Hector Gustavo Serrano Gutierrez · Accepted solution]

Hi @syed.saaud,

You should use a dedicated Layer 3 port to connect Leaf-to-Spine links for VXLAN underlay, otherwise forwarding encapsulation/decapsulation of VXLAN may not behave as expected.

You can add a new link for this purpose and once you have VXLAN up and running you can consider migrating this Vlan-interfaces to communicate over VXLAN to leverage its benefits.

Regards.