Deployment Guide

10 Dell EMC Networking Virtualization Overlay with BGP EVPN
3.1 The VXLAN protocol
VXLAN allows a Layer 2 network to scale across the data center by overlaying an existing Layer 3 network
and is described in Internet Engineering Task Force document RFC 7348. Each overlay is referred to as a
VXLAN segment.
Each segment is identified through a 24-bit segment ID referred to as a VNI. This allows up to 16 Million VNIs,
far more than the traditional 4,094 VLAN IDs allowed on a physical switch.
VXLAN is a tunneling scheme that encapsulates Layer 2 frames in User Datagram Protocol (UDP) segments,
as shown in Figure 7.
VXLAN encapsulated frame
VXLAN encapsulation adds approximately 50 bytes of overhead to each Ethernet frame. As a result, all
switches in the underlay (physical) network must be configured to support an MTU of at least 1600 bytes on
all participating interfaces.
Note: In this deployment example, switch interfaces are set to their maximum supported MTU size of 9216
bytes.
VTEPs handle VXLAN encapsulation and de-encapsulation. In this implementation, the leaf switches are the
VTEPs.