If OpenDaylight succeeds in its goals, it will provide a common approach on which a broad group of vendors, including Microsoft, will offer virtualized networking. OpenDaylight aims to "accelerate adoption, foster new innovation and create a more open and transparent approach to software-defined networking." It is supported by Brocade, Cisco, Ericsson, Juniper Networks, HP, Arista, Red Hat and other players, including Microsoft and IBM.
Since IBM is donating a chunk of its own approach to SDN to OpenDaylight, it's worth taking a look at how its approach works. Inder Gopal, IBM VP of system networking development, and Renato Recio, an IBM Fellow and CTO of system networking, discussed that approach in recent interviews. Gopal is chairman of the board of OpenDaylight.
Gopal said networks lack an operating system with the consistency that Linux has brought to commodity servers. At the moment, Cisco OnePK, VMware, Juniper and HP have their own SDN product sets, leaving virtual networking where "Unix was in the 90s," with different vendors coming up with their own implementations, said Gopal. "That's not the right model. The model needs to be open source, one that we all can leverage," he said.
Software-defined networking is trying to replace Spanning Tree and other established network protocols, relying on distributed intelligence in smart devices with centralized intelligence that tells simplified network devices what to do. The changeover would allow more flexible, reconfigurable networks that better fit virtualized environments.
[ Want to learn more about the movement to software-defined networking? See SDN: Physical Vs. Logical. ]
"The SDN vision is to take the distributed logic on the network and centralize it," said Recio. Spanning tree lets switches and routers plot optimal paths between two points, then builds switching and routing information into the distributed devices.
Enterprise data centers can get to software-defined networking by building out new networks based on the OpenFlow protocol and OpenFlow switches from a variety of vendors, including Big Switch, IBM, Juniper and HP. These can be run by an OpenFlow-based network controller, such as the IBM Programmable Network Controller, which sits on commodity hardware and becomes the brains of the network, telling OpenFlow switches and routers what route to follow in moving messages.
That still leaves the problem of making existing networks more flexible and programmable, and for that IBM recommends IBM SDN for Virtual Environments. SDN for VE is an IBM network overlay software that gives existing network hardware the capability to be subdivided into virtual nets, using a tunneling protocol much like VMware's VXLAN. It allows virtual nets to be created at a pace that matches the creation of virtual machines in a VMware or other virtualized environment.
SDN for VE allows network management to move out of the switch configuration stage into a control panel, where hundreds of physical switches may be configured and reconfigured. It works with the IBM 5000V switch, released in May 2012, which competes with the Cisco 1000V switch for virtual machines.
Information on the IBM website says SDN for VE can scale to 16,000 virtual networks and that it solves a scalability problem inherent in expanding some virtual environments.
IBM is working on adding the ability to commission firewall and load balancing services to the process of commissioning virtual machines and their networks, allowing a virtual machine's network resources to follow it around as it is migrated. It plans to be able to do so by the first half of 2014, Gopal said.
DOVE is Distributed Overlay Virtual Ethernet, IBM's original software approach for managing hypervisor-to-hypervisor traffic. DOVE has been incorporated into SDN for VE; it generates a point-to-point tunnel between the virtual switches found in hypervisors. IBM is donating this code into OpenDaylight, where it is expected to gain multi-hypervisor support, including Red Hat's KVM and Microsoft's Hyper-V.
Juniper appears to agree with IBM that the future of software-defined networking will be open source code based. It just made its SDN offering open source with the OpenContrail.org project. VMware's Nicira networking unit contributes to OpenStack's Neutron open source virtual networking project as well, although VMware's NSX Platform remains proprietary. The world will soon see competing open source approaches to SDN.
More than 100 developers are working on OpenDaylight's APIs, Gopal claimed. OpenStack has higher numbers of developers for the whole project, but it's unlikely that its Neutron platform contributors number many more than OpenDaylight's. IBM is trying to say the SDN platform effort that it backs is as well supported as anyone's.