Infrastructure // Networking
06:05 PM
Connect Directly
Repost This

SDN: Your Next Network

Software-defined networking has the potential to bring new levels of automation and efficiency to networks, but competing visions mean IT has to pay close attention to the differences.

Two Competing Visions Of SDN

While the ONF approach is most commonly associated with SDN, there are two other emerging visions for software-driven networks. The second approach also separates the control and forwarding planes, but it does so by leveraging a virtual switch such as Cisco's Nexus 1000v, VMware's DVS or IBM's DVS 5000v. In this approach, the virtual switch functions as a forwarding engine that is programmed by a device that is separate from the virtual switch. This functionality is used as part of an overlay network that rides on top of the existing network infrastructure using protocols such as Virtual Extensible LAN or Network Virtualization using GRE.

This approach may appeal to existing customers of Cisco and VMware--the dominant vendors in the networking and server virtualization markets, respectively. However, it's only applicable for hypervisor-based virtual switches, not physical switches. In addition, support for functionality such as VXLAN and NVGRE is only now emerging.

The third approach uses direct programmatic interfaces via APIs into network devices, which are broadly defined to include devices that operate at Layers 2 through 7 of the OSI-defined network stack. In this case, the control and forwarding planes aren't separated, nor is the control plane centralized.

Many network vendors, including Cisco, are adopting this approach. This summer, Cisco announced that as part of its SDN approach it will offer APIs into multiple Cisco platforms, including its IOS, IOS XR, IOS XE, and NX-OS operating systems. Cisco says this will allow for tight integration with software applications and provide better control of the network infrastructure.

Along with Cisco, Arista, Extreme Networks, and Juniper Networks all provide direct access to their platforms via APIs.

One advantage of this approach is that it enables very detailed access and control when it comes to network devices. It also avoids the interoperability shortcomings that are associated with the OpenFlow protocol. Because this approach doesn't rely on a centralized controller, it also avoids the availability and security problems that can be associated with a controller-based architecture (that is, if the controller dies, so does the ability to move traffic through the network).

On the downside, this approach is vendor-specific. In a multivendor network environment, this approach would result in "islands of control" whereby the operator would have differing levels of control of the network equipment based on the provider of that equipment.

chart: Which of these data center LAN challenges do you believe SDN can be most helpful in overcoming?

3 of 5
Comment  | 
Print  | 
More Insights
2014 Private Cloud Survey
2014 Private Cloud Survey
Respondents are on a roll: 53% brought their private clouds from concept to production in less than one year, and 60% ­extend their clouds across multiple datacenters. But expertise is scarce, with 51% saying acquiring skilled employees is a roadblock.
Register for InformationWeek Newsletters
White Papers
Current Issue
InformationWeek Elite 100 - 2014
Our InformationWeek Elite 100 issue -- our 26th ranking of technology innovators -- shines a spotlight on businesses that are succeeding because of their digital strategies. We take a close at look at the top five companies in this year's ranking and the eight winners of our Business Innovation awards, and offer 20 great ideas that you can use in your company. We also provide a ranked list of our Elite 100 innovators.
Twitter Feed
Audio Interviews
Archived Audio Interviews
GE is a leader in combining connected devices and advanced analytics in pursuit of practical goals like less downtime, lower operating costs, and higher throughput. At GIO Power & Water, CIO Jim Fowler is part of the team exploring how to apply these techniques to some of the world's essential infrastructure, from power plants to water treatment systems. Join us, and bring your questions, as we talk about what's ahead.