In my previous NSX articles we covered installing and configuring NSX, We discussed deploying/configuring Transport Zones, Logical Switches, Logical Routers, Edge Gateways, and connecting the Logical and Edge Gateways. With all these completed we now have an environment that with the appropriate routes and transport traffic from our physical network to our logical networks that we deployed. The missing price is the routes. We could go and configure a bunch of static routes throughout all the NSX routers and our physical routers, but that wouldn’t be fun. It also wouldn’t be automated. In this post I am going to walk through configuring the NSX routers to use OSPF for route distribution.
This article builds on my previous article Deploying an Edger Gateway. In this article we are going to connect the Edge router we deployed in my previous post to the Logical Router we deployed in the post Deploying Logical Distributed Routers. In order to link these together we will need to deploy a Logical Switch to be used as a transit network between the Edge Gateway and the Logical Router.
Connecting the Logical and Edge Router
So far we have deployed (2) Logical Switches and (1) Distributed Logical Router and deployed a VM on to each logical switch. Our VM’s can communicate with each other across the Distributed Logical Router, but they can’t communicate to anything else. What we now need to do is deploy an Edge Gateway that we will configure to communicate upstream to the physical network and downstream to the logical network. Where we could technically just connect the Distributed Logical Router upstream to your physical network, it’s not really a best practice approach and it’s not a supported approach when integrating with vCAC.
In this walk-through we will be deploying a logical router and configuring routing between (2) logical networks that we created in an earlier post. Logical routers consist of two components. A virtual appliance that is deployed into your vSphere environment. In the MoaC lab all routers are deployed to our management cluster and the vSphere Kernel module. Remember the host preparations we performed as part of the NSX installation? That was installing the NSX kernel modules.
The NSX Logical Routers Perform East-West (VM-VM) routing as well and North-South Routing. The East-West routing performed by the Logical Routers afford you some extra efficiencies by allowing VM-VM communications across different subnets to happen at the vSphere Kernel when those vm’s reside on the same host. You can also gain efficiencies when communicating between vm’s on different hosts as well. Traffic for the communications will traverse host to host instead of needing to go out to a physical router on the network and then to the other vm. In the post you will witness this as we place a virtual machine on each of the logical switches we created and the Logical Router performs routing between the two networks right in the hosts kernel. Although this specific post focuses on the East-West routing within the Logical Router we will be covering the North-South routing configuration in another post.