Introduction
In order to have
IP connectivity between hosts A and B over the underlay transport network, we
need to build a tunnel (IPSec or GRE) between the Public IP addresses of vEdge devices (TLOC Routes).
Then we also need VPN-specific subnet routing information (OMP Routes) to be
able to route traffic over the tunnel. This chapter discusses the role and
operation of various protocols involved in Control Plane operations when an
MPLS Transport network is used as an Underlay Network for SD-WAN solution. The
first section introduces the Segment
Routing solution for building a Label
Switch Path (LSP) between PE routers over the MPLS backbone by using the
IS-IS routing protocol for both routing and label distribution. The second
section explains how to build L3VPN between vEdge Public IP addresses over the
LSP. Figure 4-1 shows the high-level routing model used in this chapter.
Figure 4-1: Control Plane Model.
