6.4 NSX Distributed Logical Router Control VMs
Deploying a distributed logical router also deploys a controller VM that lives within the edge cluster. You can specify that the control VMs use high availability, which deploys an active/standby specification to improve availability.
The primary function of the distributed logical routing feature in the VMware NSX platform is to provide an optimized and scalable way of handling East/West traffic in a data center.
When routing between virtual networks, these Layer 3 networks are distributed in the ESXi hypervisor. Here the distributed logical router optimizes the routing and data path, and supports both single-tenant or multi-tenant deployments. For example, a network contains two VNIs that have the same IP addressing. With this scenario, two different distributed logical routers must be deployed with one distributed logical router connecting to tenant A and one to tenant B.
It is the job of the NSX Manager to configure and manage the routing service. During the configuration process, the NSX Manager deploys the logical router control virtual machine and then pushes the logical interface (LIF) configurations to each host through the control cluster. The logical router control virtual machine is the control plane component of the routing process and the logical router control virtual machine supports both the OSPF and BGP protocols.