Use Case and Reference Architecture

Modern enterprises have business-critical applications running in multiple private and public data centers. They use WANs to connect their data centers and provide access to users in remote campus and branch locations. Figure 1 depicts a typical large-scale enterprise network. The enterprise owns and operates a private data center.

Figure 1: Typical Enterprise Network

The enterprise data center uses EVPN-VXLAN as an overlay protocol and a spine and leaf architecture. This JVD terminates the VXLAN tunnels on the data center edge/gateway devices. Remote campus and branch locations access the data center resources over the WAN using L2 EVPN-MPLS connections. EVPN-MPLS has become the dominant technology for enabling connectivity between enterprise campus and branch offices. It replaces the legacy VPLS interconnect model.

The advantages of an EVPN-MPLS-based architecture include:

Multihoming
Rapid convergence
Active/active or active/standby attachment points
BGP-based MAC learning

The data center edge/gateway devices process all network traffic that enters and exits the data center. They connect the enterprise data center to the WAN and interconnect the EVPN-VXLAN tunnels in the data center with the EVPN-MPLS tunnels in the WAN. Juniper Networks MX Series routers running Junos OS Release 21.4R1 or earlier provide interconnection services using logical tunnel interfaces. This solution has some performance limitations because two separate forwarding tables are used, and packets are processed twice by the packet forwarding engine (PFE). Newer Junos OS releases use a single forwarding table and do not require data plane packet recirculation.