Deployment Guide

13 VCF on VxRail Multirack Deployment using BGP EVPN
3 Network transport
VMware Validated Design supports both Layer 2 and Layer 3 network transport. In this section, the details of
the Layer 3 leaf-spine topology are provided.
Note: Most of the steps in this section may already be done if all of the configuration steps from the VCF on
VxRail multirack deploying using BGP EVPN deployment guide were followed. To ensure completion, the
necessary steps are included in this section.
3.1 Layer 3 leaf and spine topology
In this document, a Clos leaf-spine topology is used for each availability zone. Individual switch configuration
shows how to set up end-to-end Virtual Extensible Local Area Networks (VXLANs). External Border Gateway
Protocol (eBGP) is used for exchanging IP routes in the IP underlay network, and EVPN routes in the VXLAN
overlay network. Virtual Link Trunking (VLT) is deployed between leaf pairs and internal BGP (iBGP) to
provide Layer 3 path redundancy in the event a leaf switch loses connectivity to the spine switches.
Layer 3 IP fabric
Spine 1
Z9264-ON
Spine 2
Z9264-ON
Leaf 1A
S5248F-ON
Leaf 1B
S5248F-ON
Leaf 2A
S5248F-ON
Leaf 2B
S5248F-ON
L3
L2
Layer 3 IP network transport
3.2 BGP EVPN VXLAN overview
EVPN is a control plane for VXLAN that is used to reduce flooding in the network and resolve scalability
concerns. EVPN uses multiprotocol BGP (MP-BGP) to exchange information between VXLAN tunnel
endpoints (VTEPs). EVPN was introduced in RFC 7432, and RFC 8365 describes VXLAN-based EVPN.
VXLAN-based EVPN is a next-generation VPN. It is intended to replace previous generation VPNs like Virtual
Private LAN Service (VPLS). Some of its key features are:
• Support for multitenancy
• Layer 2 and 3 integrated routing and bridging (IRB)
• Multihoming
• Minimization of ARP propagation
• MAC mobility (simplified VM migration)
The primary use cases for EVPN are:
• Expanding the potential number of Layer 2 domains
• Service provider multitenant hosting
• Data center interconnect (DCI)