(you may want to read my previous post on SIP interoperability in general first: SIP and interoperability)
So, SIP as an open system allows you to use SIP headers, content, and sessions in creative ways to enable new functionality. That is the core technical reason for why H.323 is on the way out in the video world. So, the discussions on the Internet regarding video conferencing interoperability miss the whole point when they talk about competition in the video conferencing industry and how interoperability may suffer. Video is not an island anymore, it’s a part of the SIP world. Yes, there is functionality that is specific to video, but when it’s implemented in SIP, the interoperability issues are exactly the same as in the rest of the SIP world: how do we make sure that people don’t have to think about whether the person they are about to call are using the same technology?
In Tandberg, we don’t really talk about video conferencing anymore. We all have video on our desktops, so we are not doing a video conferencing call, we’re making a video call. If it happens that we have a meeting with more than two people participating, well, then I guess it can be called a video conference, but we don’t call it that, it’s just a meeting. The number of scheduled video conferences is going down, we now have personal virtual meeting rooms where we meet (and for the video guys, yes, it might run on a video conferencing bridge). So, with this perspective, as a user, what do you expect? Of course, you expect to be able to make calls to anybody, regardless of whether they happen to have video capabilities, can share presentations, or are just on a mobile phone. Getting to a point where any person can call any person and if video is possible, you can “upgrade” your call, is the key to getting the penetration that we at Tandberg are sure will happen: video everywhere.
So, what does this have to do with SIP interoperability? Well, first of all, there’s an absolute need that any two people talking to each other are capable of using the full capabilities of the technology at hand, even if they happen to use technology from different vendors. Secondly, in order to get there, to make video really compelling and something people will want to use, we need to innovate and make sure that video is just a natural part of how you coordinate, communicate, and collaborate daily, hourly, until it permeates how you organize your day.
Let’s take an example from Tandberg, but an example that is relevant for SIP innovation in general. Tandberg has a feature called multi-way. Basically, it works like this: you are in a call (video or voice only) and somebody else is calling you. The person is relevant to the discussion you are having, and you want all three of you to talk to each other. You take the call and press the Join button. Boom, you are now all three in a meeting and you all get video of each other if video is available. This feature has been available on mobile and land line phones, but I don’t think a lot of people use it. However, if you have video, it’s a great addition to your work flow, as you are able to go directly from a personal call into an ad-hoc meeting and make a decision there and then. Of course, getting the person into the meeting may have been a result of you im’ing that other person and asking him to call you to discuss ABC.
If you are technically inclined, here’s some info about configuring multi-way: Tandberg Multi-way FAQ
If you looked at FAQ above, you will see that H.323 and SIP are both supported and that there is a lot of information about software versions required. So, now to the $1,000 question: can non-Tandberg SIP/H.323 devices participate in a multi-way call?
The answer is: it depends. And as you can see, it depends for Tandberg devices as well, because they need to have a certain software version. Does it work satisfactorily in any environment across any SIP devices, over the PSTN and mobile? Well, we took great care in trying to build on existing standards, but the device that initiates the join needs some special code to implement multi-way, so no, other vendors’ devices are not likely to be able to do the joining of the participants. However, they may be able to participate in the multi-way call as long as somebody else joins the call (but yes, sadly, it depends on things like having implemented some SIP functionality that some vendors may have implemented in a slightly different way)
So, look at our options: it is in our interest that as many devices as possible can be joined into a call, because it increases the value of the feature to the users. Of course, having such a functionality may be a competitive advantage, so we don’t have an incentive to help competitors in implementing the join functionality. It turns out that this lack of incentive is not really that relevant, because we have more important considerations that determine what to do next. Do we turn to IETF or SIPforum to standarize this feature? No, it’s too small to justify the work of doing that, even if we had an incentive. We have other worries, we need to make sure that Tandberg’s own devices support the functionality. Tandberg is pretty decentralized when it comes to development and a lot of our own functionality is tested in a very similar way to SIPit events, between QA/developers from each team.
But if somebody has implemented a similar feature in their products and at a SIPit we have been through all the basic interop stuff that we have to do, it’s very likely that multi-way interop could be tested. Some of our best engineers go to the SIPit events.
Of course, in the field, where sales people compete (as opposed to in engineering, where we normally are very friendly to each other), Tandberg may be accused of having a proprietary feature called multi-way. In some sense, it might be true and the customer may not see the nuances. From a product strategy point of view, we would much rather have multi-way become a universal feature, so that we could innovate on top of that and bring even more value. And this is true as long as doing so will increase the attractiveness of video to people so that more people buy video so that video becomes ubiquitous (once the market matures, this will no longer be true, of course. But looking at the video device sales numbers, we have still a bit to go…).
This example was from the video communication world, but I believe any manufacturer of SIP equipment have same dilemmas when it comes to deploying resources on interoperability. If all SIP protocol exchanges needed certification, the multi-way feature would have taken years (if at all), but interoperability suffers short-term.