EVPN in the Data Center

Chapter 3. The Building Blocks of Ethernet VPN

Border Gateway Protocol (BGP) is the brain that drives Ethernet VPN (EVPN). In this chapter, we study the building blocks of BGP that are responsible for the construction of virtual network overlays. There are two facets to these building blocks: the BGP peering model, and the model for exchanging routing information.

The reason to study these models is to help a network administrator understand how to deploy EVPN in the data center. The primary takeaway of this chapter is that EVPN deployment in the data center can be simpler than its service provider (SP) counterpart.

Let’s kickstart the chapter with a brief history of EVPN. This helps the reader understand the motivation behind EVPN. We next look at how BGP peering for EVPN was designed for the SP network. This leads us to see how BGP peering works in the data center in the absence of EVPN and how this affects the way EVPN is deployed in the data center. The next section deals with the fundamental BGP constructs that EVPN uses. The final two sections deal with additional constructs necessary to allow EVPN to work with external Border Gateway Protocol (eBGP) in Free Range Routing (FRR) and non-FRR routing suites. At the end of this chapter, you should be able to understand the choices in deploying EVPN in the data center.

A Brief History of EVPN

Virtual Private Networks (VPNs) interconnect multiple private networks across a public network. As discussed in Chapter 2, the interconnection ...