VXLAN with SVIs and Trunk Uplinks

[de1denta]

Hi All,

I'm attempting to configure VXLAN in a topology similar to the following from the Nexus 9K VXLAN configuration guide using Nexus 9200 series switches, however, I need to use trunk interfaces between the VTEP 9Ks and our L3 core switch with SVIs configured on the 9Ks to establish the underlay IP routing using OSPF. We are running NXOS version 7.0(3)I7(1)

The underlay IP/multicast connectivity works correctly and the NVE interfaces come up and the VTEPs peers are discovered, however, basic IP connectivity between Hosts A and B fails. If I temporarily change the VTEP to core trunk interfaces to either mode access (with the access VLAN matching the L3 SVI) or if I change to routed ports as shown in the above diagram, everything works perfectly. 

Has anyone seen this issue before? Is the use of SVI interfaces to form the underlay a known bug/limitation with VXLAN?

Thank you

[Andrea Testino]

Will,

SVI as uplinks are not supported for EVPN VXLAN deployments.

In the event of a VXLAN Flood & Learn deployment: You may be missing the "system nve infra-vlans" on the Nexus 9200s; this is a requirement when using a non-VXLAN VLAN as an underlay uplink toward the Spine (Core port) between vPC Leaf Switch nodes with the purpose of acting as a backup link in the event of a link failure between Leaf and Spine nodes.

You can found a bit more information about this command here:

When using SVI uplinks with VXLAN enabled on Cisco Nexus 9200 platform switches and Cisco Nexus 9300-EX platform switches, use the system nve infra-vlans command to specify the VLANs that are used for uplink SVI. Failing to specify the VLANs results in traffic loss.

Note	The system nve infra-vlans command specifies VLANs used by all SVI interfaces for uplink and vPC peer-links in VXLAN as infra-VLANs. You should not configure certain combinations of infra-VLANs. For example, 2 and 514, 10 and 522, which are 512 apart.

[CiscoBrownBelt]

I am trying to build a Spine Leaf lab topology. Does anyone happen to have a good guide I can refer too? I am kinda confused with certain things.

So far I am using the following:

Overlay:
Use VXLAN/EVPN

Underlay:
OSPF - routing

BGP
ECMP - for load sharing

One question I have is are the VXLAN configs (VTEPs, VNI, etc) just entered on the leaves?

Can I simply swap out OSPF with EIGRP and is that really recommended if a Data Center is not planed to scale too large especially if Vmotion will not cross the WAN or something?

[Vl@d@Ni]

Hi,

just wondering if you sort out this issue? I have the same problem.