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VxLAN

Introduction

Virtual eXtensible LAN (VXLAN) is a network overlay encapsulation protocol that aims to extend and distribute layer 2 networks on top of layer 3 topologies. Using a 12-bit Virtual Network Identifier (VNI) it allow to separate about 16 million logical network domains.

The official VXLAN documentation can be found in RFC 7348

WARNING: baseboxd does not yet support multicast groups for establishing communication among multiple VXLAN Tunnel Endpoints (VTEPs), only unicast is supported. This means you can not use the group key in the VXLAN section as documented in systemd-netdev

WARNING: baseboxd does not yet support VXLAN on bonded interfaces.

WARNING: The Accton AS4610 platform does not have VxLAN support. See our Limitations page for more information.

Sample VxlAN configuration

+-----------------------------------------------+         +-----------------------------------------------+
|                       switch-1                |         |    switch-2                                   |
|   +--------------+                   +--------+         +--------+                   +------------+     |
|   | vxlan50000   +-------------------+ port54 +---------+ port54 +-------------------+ vxlan50000 |     |
|   ++-------------+    192.168.0.1/24 +--------|  vxlan  |--------+  192.168.0.2/24   +--------+---+     |
|    |                                          |         |                                     |         |
|    | VLAN 300                                 |         |                           LAN 300   |         |
|    |                                          |         |                                     |         |
|   ++-------------+                            |         |                            +--------+-----+   |
|   | swbridge     |                            |         |                            | swbridge     |   |
|   ++-------------+                            |         |                            +--------+-----+   |
|    | VLAN 300                                 |         |                           LAN 300   |         |
|    |     |                                    |         |                                |    |         |
|    |     |                                    |         |                                |    |         |
|    |     |                                    |         |                                |    |         |
|    | Untag VLAN                               |         |                          Untag VLAN |         |
|  +-+------+                                   |         |                               +-----+----+    |
|  | port2  |                                   |         |                               | port2    |    |
+--+-+-+----------------------------------------+         +-----------------------------------+-+-+-------+

The configuration give below will create a VXLAN overlay with VNI=50000 between port54 on switch-1 and port54 on switch-2. The layer 2 domain containing port2 and port2 bridged on the swbridge on switch-1 and switch-2 is extended via the before mentioned VXLAN overlay network with the VNI 50000.

systemd-networkd

The configuration with systemd-networkd can be done with the following files.

Create bridge swbridge with no DefaultPVID.

switch-1 /etc/systemd/network/20-swbridge.netdev

[NetDev]
Name=swbridge
Kind=bridge

[Bridge]
VLANFiltering=1
DefaultPVID=none

Tag swbridge with VLAN=300 and set it up.

switch-1 /etc/systemd/network/20-swbridge.network

[Match]
Name=swbridge

[BridgeVLAN]
VLAN=300

Add VLAN tag VLAN=300 on port2 incoming traffic, untag the outgoing one, attach it to swbridge and set it up.

switch-1 /etc/systemd/network/10-port2.network

[Match]
Name=port2

[Network]
Bridge=swbridge

[BridgeVLAN]
PVID=300
EgressUntagged=300

Add ip address 192.168.0.1/24 to port54, define it as underlying interface for netdev vxlan50000 (created below) and set it up.

switch-1 /etc/systemd/network/10-port54.network

[Match]
Name=port54

[Network]
VXLAN=vxlan50000
Address=192.168.0.1/24

Create netdev vxlan50000 for VXLAN with the VNI 50000 and set local and remote VXLAN Tunnel Endpoints(VTEPs).

switch-1 /etc/systemd/network/300-vxlan50000.netdev

[NetDev]
Name=vxlan50000
Kind=vxlan

[VXLAN]
VNI=50000
DestinationPort=4789
Local=192.168.0.1
Remote=192.168.0.2

Forward VLAN tagged traffic with VLAN=300 on vxlan50000 and attach it to swbridge. Bind port54 as the carrier device to align the behaviour and state (up/down) of vxlan50000 to its underlying interface. DestinationPort=4789 sets the destination UDP port to follow the IANA standard from rfc7348. If no port is set systemd will use the default Linux kernel value 8472.

WARNING: baseboxd currently sets the local VTEP Termination port to 4789, which means that every remote VTEP must use DestinationPort=4789.

switch-1 /etc/systemd/network/300-vxlan50000.network

[Match]
Name=vxlan50000

[Network]
BindCarrier=port54
Bridge=swbridge

[BridgeVLAN]
VLAN=300

The configuration files for switch2 are identical to those of switch1 with the execption that the IPv4 addresses for the VTEP, Remote and Local will switch. Therefore the files below are shown without additional explanation.

switch-2 /etc/systemd/network/20-swbridge.netdev

[NetDev]
Name=swbridge
Kind=bridge

[Bridge]
VLANFiltering=1
DefaultPVID=none

switch-2 /etc/systemd/network/20-swbridge.network

[Match]
Name=swbridge

[BridgeVLAN]
VLAN=300

switch-2 /etc/systemd/network/10-port2.network

[Match]
Name=port2

[Network]
Bridge=swbridge

[BridgeVLAN]
PVID=300
EgressUntagged=300

switch-2 /etc/systemd/network/10-port54.network

[Match]
Name=port54

[Network]
VXLAN=vxlan50000
Address=192.168.0.2/24

switch-2 /etc/systemd/network/300-vxlan50000.netdev

[NetDev]
Name=vxlan50000
Kind=vxlan

[VXLAN]
VNI=50000
DestinationPort=4789
Local=192.168.0.2
Remote=192.168.0.1

switch-2 /etc/systemd/network/300-vxlan50000.network

[Match]
Name=vxlan50000

[Network]
BindCarrier=port54
Bridge=swbridge

[BridgeVLAN]
VLAN=300

Restart systemd-networkd or reboot the switches to apply network configuration.