DCI solution details
EVPN provides network mapping intelligence and enables the VTEPs to exchange endpoint reachability information with each other. EVPN is used as the overlay control plane, which is a standards-based protocol that carries both layer 2 and layer 3 information to optimize routing and switching decisions. It uses MP-BGP for MAC and IP address endpoint distribution. VXLAN tunnels are established between data centers that carry traffic between the endpoints.
Each data center has VTEPs that establish VXLAN tunnels to the other data centers. The underlay network for the VXLAN tunnels can be an IP-based network—it would not have any intelligence of the data centers, but provides reachability for the data centers by using routing protocols. VSX logical VTEP would be used to provide VTEP high availability.
Following are the two solutions for deploying DCI using AOS-CX switches:
- L2 DCI over VXLAN (Figure 1): L2 DCI over VXLAN refers to the solution that uses only L2 VTEP functionality.
- L3 DCI over VXLAN (Figure 2):
L3 DCI over VXLAN refers to the solution that uses both L2 and L3 VTEP functionality. Traffic between data centers can reach other data centers over multiple underlay links with Equal Cost Multi Pathing (ECMP) as shown in both Figure 1 and Figure 2.
The following sections describe the various scenarios for VXLAN DCI solution:
