VMware NSX provides two mechanisms to achieve routing; the first tier of routing is performed by the Distributed Logical Router (DLR), and the second tier of routing is performed by the Edge services gateway (ESG).
The first tier of routing is known as distributed routing and it's performed by the DLR in the ESXi Hypervisor. Distributed routing is an integral part of any NSX deployment and is usually the first hop for virtual machines that are associated with a logical network; this is because the DLR runs in the ESXi kernel and is highly optimized for "east-west" traffic flows within the data center.
The secondary tier of routing is performed by the ESG. The ESG is a multifaceted device within NSX that provides many different services, but in this chapter, we will only explore its routing capabilities. The ESG comes in a virtual machine form factor...