OSPF on nsx-t

[Rob80]

Hi all,

I am trying to configure OSPF on nsx-t, but experience issue whilst setting up interfaces on T0. According to guidance, I should be able to create 2 interfaces for each edge node, but in my case I am able only to configure one per node and having trouble with second, message pops out that this segment is already been used.

My setup - 2 VLAN segments connecting to 2 subnets on L3 switch.

Thanks n advance

[Sreec]

Have you created Two VLAN segments in NSX-T which are tagged with OSPF Transit VLAN? If that is the case it should work.

[Rob80]

Hi Sreec,

Attached screens from my setup and brief explanation below:

1. on TOR switch I have 2 subnets with vlan tag 2011 and 2012

2. same setup with tags on vmware VDS

3. on nsx-t when I set these tags I have no traffic passing, only when I set tag to 0 I have traffic.

Thanks

[Sreec]

Ok, the most likely issue is with Edge Fast Path Interfaces (DVS port group). Can you confirm if you are using the same subnet for Edge and Host TEP?  Also please do share the screenshot of DVS port group VLAN mapping. 

[Rob80]

I have Edge-VTEP with VLAN tag 1020 set as overlay to host on Compute VDS, Uplinks are on NSX-T vds as per attachment.

Edge Vtep is different subnet to Edge uplinks.

Just realised, I have in the photo nsx logical switch, but not sure when this has been created.

Thanks

[Sreec]

Thanks. Does that mean Edge TEP and Host TEP are sharing VLAN  1020? 

[Rob80]

I believe so.

[Sreec]

In this case, you need to create Edge Fast Path Interface Portgroups in NSX-T ( VLAN backed segment with required VLAN or Trunk the segments for Overlay and OSPF ). Then Create OSPF segments ( 2 for each VLAN which is already done) and attach them to OSPF interfaces. 

[Rob80]

Would you be able to elaborate steps regarding Edge fast path and portgroups in NSX-T, based on my environment?

Thanks

[Sreec]

All you need to do is, created two VLAN-backed segments in NSX-T. Based on your design, you can tag the overlay & OSPF VLANS on those segments. Edit the existing Edge nodes and change the fast path interfaces to newly created two VLAN-backed segments. 

[Rob80]

Hi Sreec,

I have done the following:

Created 2 Vlan uplinks on Tor switch and assign 2011 and 2012 tags respectively, same vlans and VDS with same tagging . Attached these vlans to vedges as an uplink 1 and 2, but have no traffic coming through.

If I change on segment 2011 to vlan 0, traffic is coming through, but not if it 2011. On second unlink 2012, even if I do 0 or 2012, I don't have traffic either way. 

[Sreec · Accepted solution]

assign 2011 and 2012 tags respectively, same vlans and VDS with same tagging

I hope you are still not using VDS portgroups.

If I change on segment 2011 to vlan 0, traffic is coming through, but not if it 2011. On second unlink 2012, even if I do 0 or 2012, I don't have traffic either way.

Please Keep the segment VLAN the same as  OSPF VLAN and connect a Windows/Linux VM directly to that segment and confirm if you have reachability to OSPF peering IP. This will help to isolate the issue.