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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.⁵

The VXLAN specification was originally created by VMware, Arista Networks and Cisco.⁶⁷

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,⁸ Broadcom, Citrix, Pica8, Big Switch Networks, Arrcus, Cumulus Networks, Dell EMC, Ericsson, Mellanox,⁹ Red Hat,¹⁰ Joyent, and Juniper Networks.

Open source

• FreeBSD,¹¹
• OpenBSD,¹²
• 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 7348.¹³ VXLAN encapsulates a MAC frame in a UDP datagram for transport across an IP network,¹⁴ 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.

See also

• Distributed Overlay Virtual Ethernet (DOVE)
• Ethernet VPN (EVPN)
• GENEVE, an industry effort to unify both VXLAN and NVGRE technologies
• Generic routing encapsulation (GRE)
• IEEE 802.1ad, an Ethernet networking standard, also known as provider bridging, Stacked VLANs, or simply Q-in-Q.
• IEEE 802.1ah, an IEEE Ethernet networking standard, also known as Provider Backbone Bridging (PBB) or MAC-in-MAC.
• NVGRE, Network Virtualization using GRE, which is a similar competing specification to VxLAN.
• Overlay Transport Virtualization (OTV)
• Virtual LAN (VLAN)
• Layer 2 Tunneling Protocol (L2TP)

External links

• VXLAN Deep Dive: Part 1 and Part 2, November 2012, by Joe Onisick

References

1. Herrod, Steve (August 30, 2011). "Towards Virtualized Networking for the Cloud". VMware. Archived from the original on 2011-09-12. Retrieved 2013-02-25. https://web.archive.org/web/20110912122246/http://blogs.vmware.com/console/2011/08/towards-virtualized-networking-for-the-cloud.html ↩

2. "Configuring VXLANs" (PDF). Cisco. Retrieved 2024-04-17. 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 ↩

3. Andre Pech (2013-11-08). "Running OpenStack over a VXLAN Fabric" (PDF). openstack.org. pp. 8, 12. Retrieved 2016-07-04. https://www.openstack.org/assets/presentation-media/OpenStackOverVxlan.pdf ↩

4. "Open vSwitch Manual: vtep – hardware_vtep database schema". openvswitch.org. Retrieved 2016-07-04. http://openvswitch.org/support/dist-docs/vtep.5.html ↩

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 http://www.arista.com/en/company/news/press-release/21-company/press-release/1016-pr-20141022 ↩

6. Timothy Prickett Morgan (30 August 2011). "VMware, Cisco stretch virtual LANs across the heavens". The Register. Retrieved 2013-02-25. https://www.theregister.co.uk/2011/08/30/vmware_cisco_vxlan_spec/ ↩

7. "VXLAN Bridges Virtual and Physical Networks to the Cloud" (PDF). Retrieved 2013-12-01. http://www.arista.com/media/system/pdf/TechBulletins/VXLAN_Overview.pdf ↩

8. "Huawei CE12800 Series Data Center Switches - Huawei products". Huawei. December 2012. http://e.huawei.com/en/products/enterprise-networking/switches/data-center-switches/ce12800/ ↩

9. Timothy Pricket Morgan (April 23, 2013). "Mellanox adds VM-flitting to ConnectX-3 adapters - Going Pro with VXLAN". The Register. https://www.theregister.co.uk/Print/2013/04/23/mellanox_connectx_3_server_adapters/ ↩

10. M. Mahalingam; D. Dutt; K. Duda; P. Agarwal; L. Kreeger; T. Sridhar; M. Bursell; C. Wright (August 2014). Virtual eXtensible Local Area Network (VXLAN). Internet Engineering Task Force. doi:10.17487/RFC7348. ISSN 2070-1721. RFC 7348. Informational. https://datatracker.ietf.org/doc/html/rfc7348 ↩

11. "FreeBSD 10.2-RELEASE Release Notes". The FreeBSD Project. Retrieved 30 June 2016. https://www.freebsd.org/releases/10.2R/relnotes.html ↩

12. Reyk Floeter (October 14, 2013). "OpenBSD vxlan implementation". Reyk Floeter. http://permalink.gmane.org/gmane.os.openbsd.cvs/123361 ↩

13. M. Mahalingam; D. Dutt; K. Duda; P. Agarwal; L. Kreeger; T. Sridhar; M. Bursell; C. Wright (August 2014). Virtual eXtensible Local Area Network (VXLAN). Internet Engineering Task Force. doi:10.17487/RFC7348. ISSN 2070-1721. RFC 7348. Informational. https://datatracker.ietf.org/doc/html/rfc7348 ↩

14. M. Mahalingam (February 22, 2013). "What Is VXLAN". Huawei. Retrieved 2013-02-25. https://support.huawei.com/enterprise/en/doc/EDOC1100086966 ↩