SD-Access VXLAN

MAC-in-UDP Encapsulation.

Extends vlans to support 16 million network segments in the same administrative domain.

Image courtesy of Lost In Transit

VXLAN is VTEP to VTEP.

• Outer-IP-SRC, VTEP that originated the packet
• Outer-IP-DST IP, VTEP that needs the packet.
• Outer-MAC-SRC, VTEP that created the packet.
• Outer-MAC-DST, the device to reach the VTEP, the gateway.

Multi-destination Support is provided by multicast.

VNI

• Virtual Network Identifier.
• 24 bits, 16 million segments.
• Get mapped to multicast groups.
• Used for macrosegmentation.

VTEP

• Virtual Tunnel End point.
• Originates and Terminates tunnels.
  • push and pop VXLAN headers.

VXLAN segment

• Only devices with the same VNI can communicate.
• AKA Overlay Network

Layer 2 overlay

• VNI is matched
  • LISP Instance ID
  • VLAN

Layer 3 overlay

• Endpoints are routed
• VNI is matched
  • LISP Instance ID
  • VRF

References

Cisco Live - SD-Access Solution Fundamentals - Jerome Dolphin - BRKENS-2810

RFC 7348: Virtual eXtensible Local Area Network (VXLAN): A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks | RFC Editor

Introduction to VXLAN – Daniels Networking Blog

Cisco Live - SD-Access Best Practices - Ashley Burton - BRKENS-2502