VXLAN Part VII: VXLAN BGP EVPN –Control Plane operation

Now you can also download my VXLAN book from the Leanpub.com 

"Virtual Extensible LAN VXLAN - A Practical guide to VXLAN Solution Part 1. (373 pages)

In my previous post “VXLAN Part VI: VXLAN BGP EVPN – Basic Configurations”, I have shown how to configure the VXLAN BGP EVPN on Nexus 9000v. This post is about BGP EVPN Control Plane operation.

Figure 7-1 represents the logical structure of the example VXLAN fabric. BGP peering is established between the VTEP Leaf switches and the Spine-11 switch, which is BGP Route Reflector (not shown in figure 7-1). Both VTEP Leaf switches have a local VRF context TENANT77 that has VNI 10077 (L3VNI) attached to it and used for routing between the hosts in different vlan/vn-segment. Hosts Café and Beef are connected to vlan 10 (192.168.11.0/24), which in turns is attached to vn-segment 10000 (L2VNI). Hosts Abba and Babe are connected to vlan 20 (192.168.12.0/24), which in turns is attached to vn-segment 20000 (L2VNI). We are using auto-generated RD/RT values and ARP-suppression in both L2VNIs. Physical topology and the configurations of the switches is presented in Appendix 1 at the end of the document. For simplicity, I have used only one uplink in each VTEP switches.

 Figure 7-1: VXLAN Fabric logical structure

VXLAN Part III: The Underlay Network – Multidestination Traffic: Anycast-RP with PIM

The role of the Underlay Network, related to BUM traffic in the VXLAN fabric, is to transport ARP, ND, DHCP and other Layer 2 BUM (Broadcast, Unknown Unicast, and Multicast) traffic between the hosts connected to different VTEPs. For the Layer 3 Multicast traffic between hosts, there should be an overlay Multicast routing design. This chapter shows how an Anycast-RP with PIM can be used in a VXLAN fabric. In figure 1, we can see our example topology used in this chapter. There are two Spine switches, which shares the same Anycast-RP IP address and belongs to the same “Anycast-RP set” group (Loopback 238). In addition to that, there is an another loopback interface, which must be unique in each Spine (Loopback 511 and 512). These addresses are used as an Anycast-RP group member Id. Both addresses, shared and unique, needs to be reachable for all switches. Complete configuration can be found from the Appendix 1 at the end of the document.

Note! I am using Cisco VIRL with nxos.7.0.3.I7.1

Figure 1: Example topology with Anycast-RP - IP addresses.