Connectivity Guide

Benets of a BGP EVPN-based VXLAN
• Eliminates the ood-and-learn method of VTEP discovery by enabling control-plane learning of end-host L2 and L3 reachability
information.
• Minimizes network ooding of unknown unicast and broadcast trac through EVPN-based MAC and IP route advertisements on local
VTEPs.
• Provides support for host mobility.
BGP EVPN compared to static VXLAN
OS10 supports two types of VXLAN NVO overlay networks:
• Static VXLAN
• BGP EVPN
Congure and operate static VXLANs and BGP EVPNs for VXLAN in the same way:
• Manually congure the overlay and underlay networks.
• Manually congure each virtual network and VNI.
• Manually congure access port membership in a virtual network.
• Existing routing protocols provision and learn underlay reachability to VTEP peers.
However, static VXLANs and BGP EVPNs for VXLAN dier as described:
Table 25.
Dierences between Static VXLAN and VXLAN BGP EVPN
Static VXLAN VXLAN BGP EVPN
To start sending and receiving virtual-network trac to and from a
remote VTEP, manually congure the VTEP as a member of the
virtual network.
No manual conguration is required. Each remote VTEP is
automatically learned as a member of a virtual network from the
EVPN routes received from the remote VTEP. After a remote VTEP
address is learned, VXLAN trac is sent to, and received from, the
VTEP.
Data packets learn remote hosts after decapsulation of the VXLAN
header in the data plane.
Remote host MAC addresses are learned in the control plane using
BGP EVPN Type 2 routes and MAC/IP advertisements.
VXLAN BGP EVPN operation
The EVPN address family allows VXLAN to carry EVPN routes in External Border Gateway Protocol (eBGP) and Internal Border Gateway
Protocol (iBGP) sessions. In a data center network, use eBGP or iBGP for route exchange in both the IP underlay network and EVPN.
The following sample BGP EVPN topology shows a leaf-spine data center network where eBGP exchanges IP routes in the IP underlay
network, and exchanges EVPN routes in the VXLAN overlay network. All spine nodes are in one autonomous system—AS 65535. All leaf
nodes are in another autonomous system—AS 65000.
To advertise underlay IP routes, eBGP peer sessions establish between the leaf and spine nodes using an interface IP address. To advertise
EVPN routes, eBGP peer sessions between the leaf and spine nodes use a Loopback IP address.
VXLAN
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