Topic: Virtual eXtensible LAN(VXLAN)By Math Tea – eintellegoNetworks

math@eintellegonetworks.asia

Date: 30 March, 2016

Contentsq VXLAN Introduction

q VXLAN Benefits

q Reference

What is VXLAN?q Virtual eXtensible Local Area Network

q Stretches Layer 2 connections over a Layer 3 network by encapsulating Ethernet frames in a VXLAN packet that includes IP addresses

Layer 3 Network

Layer 2 over Layer 3Layer 2 Layer 2

VTEP-A VTEP-BHost 1 Host 2

VNI 6000

q Theoretically create as many as 16 million VXLANs in an administrative domain

q Enable migration of virtual machines between servers in separate Layer 2 domains by tunneling over Layer 3 networks

q No need to use STP to converge the topologyu All links can be used u Traffic can be load balancedu Maximizes performance

Benefits of using VXLANs

VXLAN Network Identifier(VNI)

q The VNI was designed to address the growing needs of multi-tenant data centers.

q VNI is 24 bit length which is more than 16 million VXLAN segments(224 =16,777,216)

Virtual Tunnel Endpoint(VTEP)q Devices that support VXLANs are called virtual tunnel

endpoints (VTEPs). They can be end hosts or network switches or routers.

q VTEPs encapsulate VXLAN traffic and decapsulate that traffic when it leaves the VXLAN tunnel.

q VTEPs add a number of fields, including the following:

u Outer MAC destination address (MAC address of the tunnel endpoint

VTEP)

u Outer MAC source address (MAC address of the tunnel source VTEP)

u Outer IP destination address (IP address of the tunnel endpoint VTEP)

u Outer IP source address (IP address of the tunnel source VTEP)

u Outer UDP header

u A VXLAN header that includes a 24-bit field

Virtual Tunnel Endpoint(VTEP)

VXLAN Packet format

• LSRs forward packets based on label and swap labels:

- The last LSR in the path also removes the label and forward the IP packets as normal IP Routing

Underlay Network

VXLAN Encapsulation

VNI =100

VNI =200

VNI =100

VNI =200

Overlay Network

Reference

• https://tools.ietf.org/html/rfc7348

• http://www.juniper.net/documentation/en_US/junos14.1/topics/topic-map/vxlan-qfx-series.html

• https://www.youtube.com/watchv=Jqm_4TMmQz8