VMware's Nicira Emphasizing Virtual Switches Over OpenFlow for SDN

By Jeffrey Burt  |  Posted 2012-12-29 Print this article Print

Casado said such a virtual network overlay solution offers greater upside than OpenFlow, which is being used by networking hardware makers in their switches and as the basis for software controllers. While hardware vendors are enabling their products to work with OpenFlow, there is little incentive to push for the protocol’s acceptance, he said. Doing so reduces the value the vendors get from their switches, and there is a chance that many will create OpenFlow-based switches and controllers that will tie customers to their technologies, according to Casado.

“I'm certain they will use their controller and their switches in a way that binds them together so they can maintain control” of the solutions customers use, he said.

Leveraging virtual switches offers a wide variety of advantages, according to Casado, from quick provisioning and real mobility to faster software innovation and decoupling of the hardware from the control and data planes.

“I don’t see any real reason to deploy OpenFlow switches,” he said.

Not everyone agrees with Casado. Infoblox , which offers network automation solutions as part of its larger SDN vision, is one of more than 80 members of the Open Networking Foundation, the key organization driving the development of software-defined networking and the OpenFlow protocol. In an email to eWEEK, Infoblox founder and CTO Stu Bailey disputed Casado’s conviction that the bulk of the answers to the issues dogging networks is in virtual switches as opposed to OpenFlow-based controllers and switches.

"For certain hypervisor rich workloads (e.g. scaling web servers), virtual switches at the network edge terminating in the datacenter make total sense,” Bailey said. "An organization's entire network (what is connected and how those things relate to each other throughout the day and night) is ultimately and directly accountable to the business. If the entire network cannot scale at cost, many modern organizations are limited or even crippled with respect to the business they are in. In the datacenter, the network is just one piece of the puzzle. Even in the datacenter, there are virtualization workloads which are hypervisor rich and cloud workloads like Big Data which may be closer to the bare metal. It's not clear whether virtual switches are optimized for all kinds of workloads emerging in the data center."

He also questioned whether “moving from lots of physical boxes to lots of virtual boxes” solves configuration and management issues that are found in hardware-based networking environments. OpenFlow enables the “box functions” (such as load balancing, routing, switching and firewalls) to become programmed behaviors in software, which is key to driving the SDN model.

“Virtual switches are positioned to address a particular problem emerging in the data center,” Bailey said. “Comparing OpenFlow and virtual switches is comparing apples and oranges and probably adds to the confusion of the consumer. Martin [Casado] seems to be confusing the values of virtual switches in a hypervisor rich datacenter and software defined networking (SDN)."


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