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Virtual Extensible LAN

From Wikipedia, the free encyclopedia

Virtual Extensible LAN (VXLAN) is a network virtualization technology that attempts to address the scalability problems associated with large cloud computing deployments. It uses a VLAN-like encapsulation technique to encapsulate OSI layer 2 Ethernet frames within layer 4 UDP datagrams, using 4789 as the default IANA-assigned destination UDP port number,[1] although many implementations that predate the IANA assignment use port 8472.[2] VXLAN endpoints, which terminate VXLAN tunnels and may be either virtual or physical switch ports, are known as VXLAN tunnel endpoints (VTEPs).[3][4]

VXLAN is an evolution of efforts to standardize on an overlay encapsulation protocol. Compared to single-tagged IEEE 802.1Q VLANs which provide a limited number of layer-2 VLANs (4094, using a 12-bit VLAN ID), VXLAN increases scalability up to about 16 million logical networks (using a 24-bit VNID) and allows for layer-2 adjacency across IP networks. Multicast or unicast with head-end replication (HER) is used to flood Broadcast, unknown-unicast and multicast traffic.[5]

The VXLAN specification was originally created by VMware, Arista Networks and Cisco.[6][7] Other backers of the VXLAN technology include Huawei,[8] Broadcom, Citrix, Pica8, Big Switch Networks, Arrcus Inc., Cumulus Networks, Dell EMC, Ericsson, Mellanox,[9] FreeBSD,[10] OpenBSD,[11] Red Hat,[12] Joyent, and Juniper Networks.

VXLAN is officially documented by the IETF in RFC 7348.[12] VXLAN encapsulates a MAC frame in a UDP datagram for transport across an IP network,[13] creating an overlay network or tunnel.

Open vSwitch is an example of a software-based virtual network switch that supports VXLAN overlay networks.

See also[edit]


  1. ^ Steve Herrod (August 30, 2011). "Towards Virtualized Networking for the Cloud". VMware. Retrieved 2013-02-25.
  2. ^ "Configuring VXLANs" (PDF). Cisco. Retrieved 2024-04-17.
  3. ^ Andre Pech (2013-11-08). "Running OpenStack over a VXLAN Fabric" (PDF). openstack.org. pp. 8, 12. Retrieved 2016-07-04.
  4. ^ "Open vSwitch Manual: vtep – hardware_vtep database schema". openvswitch.org. Retrieved 2016-07-04.
  5. ^ "Arista Expands Leaf Switch Product Portfolio" (Press release). Arista Networks. 22 October 2014. Retrieved 8 November 2014. Arista's updated VXLAN implementation eliminates the need for multicast in the underlay network by using Head End Replication for forwarding broadcast, multicast and unknown unicast traffic
  6. ^ Timothy Prickett Morgan (30 August 2011). "VMware, Cisco stretch virtual LANs across the heavens". The Register. Retrieved 2013-02-25.
  7. ^ "VXLAN Bridges Virtual and Physical Networks to the Cloud" (PDF). Retrieved 2013-12-01.
  8. ^ "Huawei CE12800 Series Data Center Switches - Huawei products". Huawei. December 2012.
  9. ^ Timothy Pricket Morgan (April 23, 2013). "Mellanox adds VM-flitting to ConnectX-3 adapters - Going Pro with VXLAN". The Register.
  10. ^ "FreeBSD 10.2-RELEASE Release Notes". The FreeBSD Project. Retrieved 30 June 2016.
  11. ^ Reyk Floeter (October 14, 2013). "OpenBSD vxlan implementation". Reyk Floeter.
  12. ^ a b Mahalingam, Mallik; Dutt, Dinesh G.; et al. (August 2014). VXLAN: A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks. IETF. doi:10.17487/RFC7348. RFC 7348.
  13. ^ M. Mahalingam (February 22, 2013). "What Is VXLAN". Huawei. Retrieved 2013-02-25.

External links[edit]