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The role for XMPP as a southbound SDN protocol

How can XMPP be used in hybrid software-defined networking as an alternative or complement to OpenFlow?

Extensible Messaging and Presence Protocol, originally developed for instant messaging and online presence detection, is emerging as an alternative software-defined networking (SDN) protocol.

Some researchers and vendors are exploring XMPP (Extensible Messaging and Presence Protocol) as an alternative or complement to OpenFlow in hybrid SDN networks.

Hybrid SDN models vary but can consist of an external controller, a bit of OpenFlow, some tunneling and overlays for support of heavily virtualized environments, with a lot happening on the hypervisor. Hybrid SDN allows network operators to continue supporting a range of legacy protocols and mechanisms while adding support for all of the new SDN technologies.

"XMPP can be used by the controller to distribute both control plane and management plane information to the server endpoints," explained Ankur Singla, Juniper Network's vice president of SDN and orchestration systems. "XMPP manages information at all levels of abstraction down to the flow."

"Traditional protocols are necessary for interoperability with legacy networks and systems," said Brad Casemore, research director of datacenter networks for IDC. "Because vendors have existing networking products, technologies and portfolios, they're trying to figure out how to continue supporting them while moving toward the SDN transition in the marketplace."

Juniper and Arista Networks are exploring XMPP for SDN, and other vendors may follow them.

Juniper is active within the Open Networking Foundation (ONF) and is implementing OpenFlow. "However, we view SDN as being much broader than just OpenFlow," said Singla.

For this reason, Juniper uses XMPP as a southbound protocol in its Contrail SDN controller, for separation of the control plane and data plane and configuration and management of endpoints.

Arista is using XMPP as a communications protocol for the configuration of switches, and has for quite some time, but is now tying it in with the programmability of its EOS for SDN purposes.

"As we transition toward SDN, we're seeing Arista's strategy evolve. If customers want external control in the SDN OpenFlow model, or however SDN evolves, they'll now be able to support a wide range of technologies," Casemore noted.

The biggest advantages in using XMPP as an SDN protocol? "For customers, it means avoiding being locked into a single vendor for the SDN system, which can adversely affect total cost of ownership and the rate of innovation," Singla said. "This is where interoperability and protocols increase flexibility, investment protection and operational efficiency."

Integrating existing protocols that have matured through industry-wide cooperation and standardization can help speed the transition to SDN systems. "Our customers have a large installed base of physical equipment and virtualized network services that greatly benefit from the automation and agility provided by SDN systems -- without having to rip, replace and relearn operational processes," Singla added.

Click here to learn more about using BGP as an SDN protocol.

This was last published in May 2013

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