Q: What’s a VXLAN?

A: VXLAN stands for Virtual eXtensible Local Area Network, and is a means to solve the scaling challenges of VLAN networks in a multi-tenant environment. VXLAN is an overlay network which transports an L2 network over an existing L3 network. For more information on VXLAN, please see RFC 7348.

Q: How much of the VXLAN protocol does Open vSwitch currently support?

A: Open vSwitch currently supports the framing format for packets on the wire. There is currently no support for the multicast aspects of VXLAN. To get around the lack of multicast support, it is possible to pre-provision MAC to IP address mappings either manually or from a controller.

Q: What destination UDP port does the VXLAN implementation in Open vSwitch use?

A: By default, Open vSwitch will use the assigned IANA port for VXLAN, which is 4789. However, it is possible to configure the destination UDP port manually on a per-VXLAN tunnel basis. An example of this configuration is provided below.:

$ ovs-vsctl add-br br0
$ ovs-vsctl add-port br0 vxlan1 -- set interface vxlan1 type=vxlan \
    options:remote_ip= options:key=flow options:dst_port=8472