- The focus of software defined networking (SDN) may be on the data center and carrier networks, but that doesn’t mean campus LANs can’t benefit as well.
- New technologies need a compelling reason for IT to adopt them and SDN is no different. Sure, data centers have issues that SDN can address, but users see choppy video and voice as much more urgent problems to solve.
For many, SDN is a data center and service provider play because those two areas have unique scalability and versatility demands that SDN is well suited to address. There is as much value in the campus LAN as well, and I suspect that we’ll start seeing many more reasons why SDN in the campus makes sense. Two recent examples from Aruba and Extreme both involving integration of Microsoft’s Lync unified communications software are illustrative of why.
QoS in the campus is handled by tagging traffic with different priorities, and that approach has worked well enough because IT can assume traffic to a VoIP phone is voice traffic and assign the proper tag. With softphones, desktop sharing, and desktop video, determining what type of traffic is coming from a PC can be difficult or impossible to determine because the protocols are encrypted or dynamic. Modern OSs can tag traffic before sending data onto the network, but no one wants to trust the PC—in reality, the user sitting at the PC—to classify its traffic. That’s because a savvy worker can configure their PC to tag their traffic as high priority and potentially degrade others who are working by clogging the network with, say, videos of dancing cats.
Aruba and Extreme, and I imagine other vendors will do the same, have integrated with Microsoft’s Lync so that the Lync server becomes an authoritative data source of UC&C activity from PCs on the network. Lync knows what Lync clients are doing and can tell “the network” precisely what the traffic is used for and the network, either at the AP, controller, or switch, can apply the proper tags — all without user intervention. In effect, Lync is driving the connection parameters for application traffic in the network.
But wait, there’s more: Lync also keeps track of traffic statistics collected from clients and the Lync servers, which are being brought into network management applications for reporting, troubleshooting, and alerting. Now, IT can readily track quality, and if there is a problem, drill down to the source and resolve issues quicker.
The key point here is that an application and the network are working together to improve application quality of experience from the applications point of view and doing so in an automated manner. It’s not the same kind of SDN where a controller defines paths through the network. It’s the kind of SDN where the application is telling the network how to manipulate and process its application traffic in a precise and authoritative manner.
Campus LANs aren’t physically laid out like data centers, and carriers and don’t need the same kind of path control some SDNs provide, but that doesn’t mean applications can’t be given the ability to define network processing. Call it SDN or not, it looks beneficial to me. Call me crazy, but this may be a killer app.