One of my predictions in an end-of-year blog for 2010 was that the SIP session would continue to take on an increasingly important role in the evolution of UC. I still stand by that and I’ve done a lot of thinking about that prediction since then and I do believe that delivering, securing and managing the session is a significant part of mobilizing unified communications.
Why do I believe that? Well the first step is to understand exactly what a session is. With VoIP and UC we often think of things like "calls" but in reality, the user might make a call but the system establishes a SIP session between the two end points. The session might be a voice call but could also be a video session, chat stream, it could be something sending presence information or anything else that's supported in SIP. The key though is that it is using SIP as the underlying communications protocol. Now SIP is a protocol that works at the IP layer (layer 3) of the OSI stack, and this itself is an important point. Things done at the IP layer are much more portable and dynamic than things done at layer 2. IP maintains state, layer 2 doesn't.
Think of any of the other IP based applications--the Internet, e-mail, whatever. There’s no manual coding needed when you move around, you simply pick up your device, plug in to whatever network, and access the application. In fact, you can be connected, disconnect from the network, walk to another location and reconnect and resume working in the application. This is the benefit of doing things at the IP layer. The state was maintained and the connection is dynamic and mobile.
I've argued for many years that VoIP was never really about converging voice and data. If that was important, we would all be using ATM. VoIP was about making voice an IP based application and gaining the benefits of IP. Until recently though, the "IP-ness" (careful how you read that), of voice has been limited. Most companies would deploy VoIP behind their firewall and then go PSTN everywhere else. This deployment model significantly limits the value of VoIP and UC, which is one of the reasons why we've seen an explosion in the area of SIP trunking--it allows organizations to extend the IP capabilities of VoIP and UC past the enterprise edge. If you remember back to last year’s VoiceCon, SIP trunking was a huge topic there and I'm expecting it to be so at this year’s Enterprise Connect.
Once an organization deploys a SIP based communications server (aka an IP PBX), it becomes possible to bring all the inherent characteristics of IP based applications to communications. From a vision perspective, what this allows us to do is to mobilize the communications tool. I'm not talking about making it wireless--we can doing that today--but making the content or service mobile between devices.
For example, picture a worker at a desk, and at the desk there is a desktop computing device, TV, video enabled IP phone and tablet (unless they’re an Avaya customer, then they'll have something with the Flare experience). The user might be watching TV, have some content up on the laptop and maybe a web conference going on the tablet. Then a video call comes in on the video phone from someone important (boss, customer, industry analyst) and the user wants to move the "session" to a bigger screen. From a vision perspective, it should be possible to move the video stream to the TV and move the TV feed to the IP phone. Then maybe swap the TV with what’s on the tablet. It's a bit Minority Report-ish, but it is possible to do if all of the communications tools are SIP-based sessions and all of the devices are part of the same system.
In this case, the ability to grab, move and manage the session is the key to making the content mobile, which is different than just enabling it on a wireless device. To me this is the single biggest difference between making UC truly mobile instead of just portable. The SIP session makes it possible to deliver any content or service to any device over any network, the holy grail of mobile UC. Without that we're just making calls and haven’t really changed anything. I would look for the concept of the session and the overall importance of it to become a bigger and bigger theme in this industry, and the vendor that figures out how to leverage it best stands to benefit greatly.
