Software-Defined Networking: There's More to It Than Just Hype
One of the key challenges in this early phase will be defining what exactly SDN is, what the various vendors are offering and what works best in a particular environment. Established vendors such as Cisco, Extreme Networks, Hewlett-Packard and Juniper Networks are competing against startups like Big Switch Networks and companies like Dell and VMware, data center stalwarts who are relatively new to the networking space but want to become more complete enterprise IT solution providers. Some vendors are looking to focus on Layers 2-3 to make the network themselves more automated and programmable. Others, like Embrace, want to focus higher up the stack, where the virtual services and applications—such as load balancers and firewalls—live. Still others are looking to create more complete SDN products. There's not always a lot of agreement among vendors. Martin Casado was among the founders of the OpenFlow protocol, which has become a cornerstone of SDN. However, after his company, Nicira, was bought last year by VMware, Casado said OpenFlow was the wrong approach to take and that virtual switches in hypervisors—particularly vSwitches in VMware offerings—offered the best solution for programmability and automation in networks. Gartner's Fabbi noted that lot of SDN products are on the market now to choose among, and they fall into a few categories. Vendors such as VMware, with Nicira, offer network overlays, where a virtual network is placed atop the traditional network, with networking "tunnels" created between the vSwitches and the network infrastructure. VMware is expected to integrate Nicira's technology into its virtualization offerings and commercialize it later this year, he said.However, they tend to be strictly data center platforms—rather than offerings that can work at the network edge—and add complexity with another layer on top of existing network protocols, he wrote. Other vendors, like HP, support more of an SDN "pure play," Fabbi said. The company has OpenFlow-enabled many of its switches, is developing an open controller and is enabling developers to build applications on top of the controller. However, like other vendors, "HP right now has a lot of the components, but not all of them." Bethany Mayer, senior vice president and general manager of HP Networking, told eWEEK that the company has 40 switch platforms that are OpenFlow-enabled, that its controller will be released in the second half of the year and that some of the applications currently are in beta. HP has shipped about 20 million ports of OpenFlow-enabled switches.
In a post on the No Jitter blog, Terry Slattery, a senior network engineer and a consultant with Chesapeake NetCraftsmen, said there are benefits to network overlays. "It is easy to implement and has a low cost because it only requires the addition of vSwitches for its implementation," Slattery wrote. "It allows an easy migration to the SDN world without wholesale equipment replacement."