What is VXLAN?

Welcome to VXLAN.guru!

This comprehensive tutorial will take you from zero VXLAN knowledge to expert-level understanding. We'll cover everything from basic concepts to advanced EVPN implementations, complete with configuration examples and interactive tools.

Virtual eXtensible Local Area Network (VXLAN) Overview

VXLAN is a network virtualization technology that addresses the limitations of traditional VLANs in modern data center environments. It uses MAC-in-UDP encapsulation to create logical networks that span physical network boundaries, enabling massive scalability and flexibility for cloud computing and virtualization.

Key Characteristics

  • Layer 2 over Layer 3: Extends Layer 2 segments over Layer 3 networks
  • 24-bit VNI: Supports up to 16 million logical networks
  • UDP Encapsulation: Uses UDP port 4789 for transport
  • VTEP Architecture: VXLAN Tunnel Endpoints handle encapsulation
  • Multicast Support: Leverages IP multicast for BUM traffic
  • Vendor Agnostic: Industry standard (RFC 7348)

VXLAN vs Traditional VLANs

Aspect Traditional VLAN VXLAN
Scale 4,094 VLANs 16 million VNIs
Scope Single broadcast domain Spans multiple data centers
Transport Ethernet switching IP routing
Flexibility Limited mobility VM mobility across subnets
Multi-tenancy Limited isolation Strong tenant isolation
Overhead 4-byte VLAN tag 50-byte VXLAN header

Why Learn VXLAN?

VXLAN is essential for:

  • Modern data center networking and cloud infrastructure
  • Network virtualization and Software-Defined Networking (SDN)
  • Multi-tenant environments and service provider networks
  • Data center interconnect and hybrid cloud deployments
  • Container networking and microservices architectures

The VXLAN Process

Frame Reception
→
VXLAN Encapsulation
→
IP Transport
→
VTEP Decapsulation

The VXLAN process involves four main phases:

  1. Frame Reception: VTEP receives Ethernet frame from local segment
  2. VXLAN Encapsulation: Frame is encapsulated with VXLAN header
  3. IP Transport: Encapsulated packet is routed through IP network
  4. VTEP Decapsulation: Remote VTEP strips VXLAN header and forwards

Quick Start Example

Here's a basic VXLAN configuration to get you started:

# Cisco NX-OS Configuration
feature vn-segment-vlan-based
feature nv overlay

interface nve1
  no shutdown
  source-interface loopback0
  member vni 10100
    ingress-replication protocol bgp

vlan 100
  vn-segment 10100

interface vlan100
  no shutdown
  ip address 192.168.100.1/24
  fabric forwarding mode anycast-gateway