Virtual Extensible LAN

Virtual eXtensible LAN (VXLAN) is a network virtualization technology that 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,{{cite web |author=Herrod |first=Steve |date=August 30, 2011 |title=Towards Virtualized Networking for the Cloud |url=http://blogs.vmware.com/console/2011/08/towards-virtualized-networking-for-the-cloud.html |url-status=dead |archive-url=https://web.archive.org/web/20110912122246/http://blogs.vmware.com/console/2011/08/towards-virtualized-networking-for-the-cloud.html |archive-date=2011-09-12 |access-date=2013-02-25 |publisher=VMware}} although many implementations that predate the IANA assignment use port 8472. VXLAN attempts to address the scalability problems associated with large cloud computing deployments. {{cite web|url=https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus1000/kvm/config_guide/vxlan/5x/b_Cisco_N1KV_for_KVM_VXLAN_Config_5x/b_Cisco_N1KV_for_KVM_VXLAN_Config_5x_chapter_01.pdf|title=Configuring VXLANs|publisher=Cisco|access-date=2024-04-17}} VXLAN endpoints, which terminate VXLAN tunnels and may be either virtual or physical switch ports, are known as VXLAN tunnel endpoints (VTEPs).{{cite web

| url = https://www.openstack.org/assets/presentation-media/OpenStackOverVxlan.pdf

| title = Running OpenStack over a VXLAN Fabric

| date = 2013-11-08 | access-date = 2016-07-04

| author = Andre Pech | website = openstack.org

| pages = 8, 12

}}{{cite web

| url = http://openvswitch.org/support/dist-docs/vtep.5.html

| title = Open vSwitch Manual: vtep – hardware_vtep database schema

| access-date = 2016-07-04

| website = openvswitch.org

}}

History

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.{{cite press release|url=http://www.arista.com/en/company/news/press-release/21-company/press-release/1016-pr-20141022|title=Arista Expands Leaf Switch Product Portfolio|publisher=Arista Networks|date=22 October 2014|access-date=8 November 2014|quote=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}}

The VXLAN specification was originally created by VMware, Arista Networks and Cisco.{{cite web |url=https://www.theregister.co.uk/2011/08/30/vmware_cisco_vxlan_spec/ |title=VMware, Cisco stretch virtual LANs across the heavens |author=Timothy Prickett Morgan |publisher=The Register |date=30 August 2011 |access-date=2013-02-25}}{{cite web |url=http://www.arista.com/media/system/pdf/TechBulletins/VXLAN_Overview.pdf |title=VXLAN Bridges Virtual and Physical Networks to the Cloud |access-date=2013-12-01}}

Implementations

VXLAN is widely, but not universally, implemented in commercial networking equipment. Several open-source implementations of VXLAN also exist.

=Commercial=

Arista, Cisco, and VMware were the originators of VXLAN and support it in various products.

Other backers of the VXLAN technology include Huawei,{{cite web |url=http://e.huawei.com/en/products/enterprise-networking/switches/data-center-switches/ce12800/ |title=Huawei CE12800 Series Data Center Switches - Huawei products |date=December 2012 |publisher=Huawei}} Broadcom, Citrix, Pica8, Big Switch Networks, Arrcus, Cumulus Networks, Dell EMC, Ericsson, Mellanox,{{cite web |url=https://www.theregister.co.uk/Print/2013/04/23/mellanox_connectx_3_server_adapters/ |title=Mellanox adds VM-flitting to ConnectX-3 adapters - Going Pro with VXLAN |date=April 23, 2013 |publisher=The Register |author=Timothy Pricket Morgan}} Red Hat,{{ref RFC|7348}} Joyent, and Juniper Networks.

=Open source=

FreeBSD,{{cite web|title=FreeBSD 10.2-RELEASE Release Notes|url=https://www.freebsd.org/releases/10.2R/relnotes.html|website=The FreeBSD Project|access-date=30 June 2016}}
OpenBSD,{{cite web |url=http://permalink.gmane.org/gmane.os.openbsd.cvs/123361 |title=OpenBSD vxlan implementation |date=October 14, 2013 |publisher=Reyk Floeter |author=Reyk Floeter}}
Open vSwitch is an example of a software-based virtual network switch that supports VXLAN overlay networks.

Standards specifications

VXLAN is officially documented by the IETF in RFC 7348.{{ref RFC|7348}} VXLAN encapsulates a MAC frame in a UDP datagram for transport across an IP network,{{cite web |url=https://support.huawei.com/enterprise/en/doc/EDOC1100086966 |title=What Is VXLAN |author=M. Mahalingam|date=February 22, 2013 |access-date=2013-02-25|publisher=Huawei}} creating an overlay network or tunnel.

Alternative technologies

Alternative technologies addressing the same or similar operational concerns, include:

IEEE 802.1ad ("Q-in-Q"), which greatly increases the number of VLANs supported by standard IEEE 802 Ethernet beyond 4K.
IEEE 802.1ah ("MAC-in-MAC"), which supports tunneling Ethernet in a way which greatly increases the number of VLANs supported while avoiding a large increase in the size of the MAC Address table in a Carrier Ethernet deployment.
Network Virtualization using Generic Route Encapsulation (NVGRE), which uses different framing but has similar goals to VxLAN.

References

External links

[http://www.definethecloud.net/vxlan-deep-dive/ VXLAN Deep Dive: Part 1] and [http://www.definethecloud.net/vxlan-deep-divepart-2/ Part 2], November 2012, by Joe Onisick

Category:Tunneling protocols