NSX-T BGP

[MazdaD]

Hi

Is it best practice for Tier0 Gateways to peer with  loopback Interface on the Nexus Swithes ???

Thanks

[Sreec]

You can peer with loopback if your topology and configurations allow. When it comes to routing, you shouldn't just follow best practices; instead, you should always choose what works best for the design.

[ukonstantin]

if you have more than one connection it is a best practice to peer with the loopback because it will never go down. In the case you habe only one ptp connection then it's ok to peer with the address of the peer interface. 

[MazdaD]

Hi thanks for that, is it common to use vrf on NSX-T and Nexus for NSX-T set up, we have a deployment in April and am wanting to prepare best I can for it.  ??

Thanks

[DanielKrieger]

How many uplink vlans do you use? I usually do point-to-point peering with the ToR switches. Normally I use 2 uplink vlans and pin my traffic for uplink 1 to ToR left and the traffic for uplink 2 to ToR right. Only in the event of a link failure does the traffic switch from uplink 1 to the ToR on the right. I use Named Teaming Policies and Failover Order for this.

Of course it always depends on the infrastructure, I also have a peering with a Checkpoint Firewall Cluster and NSX in one project, here I use the Cluster VIP. With a Dell VLT peer, I use the interface IPs of the switch for peering. If an interface fails, the uplink port group performs a failover. If the entire switch fails, I am informed via BFD and the routes to this switch are removed from the routing table and the uplink traffic runs via the remaining ToR switch.

I have attached a picture of my setup at the beginning. It is with 4 Fastpaht interfaces (tep and uplink separated). The actual setup is similar if only 2 fastpath interfaces are used. The T0 has 4 IP addresses (active/active 2 Edge VMs), Edge 1 - 1 IP in VLAN 30, 1 in VLAN31 and Edge 2 1 IP in VLAN 30 and 1 IP in VLAN 31. I do my BGP peering on the VLAN IP addresses on the ToR switches. ToR Left has 1 IP address in VLAN 30 (VLAN 31 has no IP on the switch but is configured for failover) and ToR Right has 1 IP address on VLAN 31 (no IP on VLAN 30).

I have also uploaded a few failover scenarios.
Here is the full link to my article:
https://evoila.com/blog/nsx-t-virtual-edge-node-with-4-datapath-interfaces/

I haven't had Cisco Nexus in any NSX projects yet, but the Nexus can do both, with or without loopback. It depends on your network setup.

If i helped you, I would appreciate Kudos. If you still have questions, ask them.

[DanielKrieger]

VRF Lite was introduced with NSX 3.0 and is currently being expanded again and again. Not everything is possible in VRFs yet, but there are certainly scenarios where VRFs are used - for example if you want to isolate tenants. However, VRFs are dependent on the T0 and the edge cluster. If your T0 or the associated edge cluster has a problem, your VRFs will also have a problem. If the edge cluster fails, all VRFs of the T0 are also affected.

With NSX 4.X it was introduced that the VRFs can now have their own AS number, in NSX 3.x this was not possible and all VRFs had the same AS number of the main T0. VRFs are nothing unusual now, but as so often, it depends on what you want to achieve with them. It is not possible to make a general statement about this