Opticall AB’s Dial over Data solution

This approach uses a SIP proxy + VoIP gateway to couple calls to and from the PSTN, SIP trunks, SIP handsets, etc. in order to reduce the cost of calls. For details see the masters theses by Max Weltz [Weltz 2008], Li Zhang [Li 2009], Xiao Wu [Wu 2009], Tao Sun [Sun 2003], and others.

Slide Notes

Max Weltz, Dial over Data solution, Masters thesis, Royal Institute of Technology (KTH), School of Information and Communications Technology, COS/CCS 2008-02, February 2008 https://urn.kb.se/resolve?urn=urn%3Anbn%3Ase%3Akth%3Adiva-91874 Links to an external site.

Zhang Li, Service Improvements for a VoIP Provider, Masters thesis, Royal Institute of Technology (KTH), School of Information and Communications Technology, TRITA-ICT-EX-2009:104, August 2009 https://urn.kb.se/resolve?urn=urn%3Anbn%3Ase%3Akth%3Adiva-91493 Links to an external site.

Xiao Wu, SIP on an Overlay Network. Masters thesis, Royal Institute of Technology (KTH), School of Information and Communications Technology, TRITA-ICT-EX-2009:105, September 2009 https://urn.kb.se/resolve?urn=urn%3Anbn%3Ase%3Akth%3Adiva-91491 Links to an external site.

Tao Sun, Developing a Mobile Extension Application: OptiCaller Application and Provisioning System. Masters thesis, Royal Institute of Technology (KTH), School of Information and Communications Technology, TRITA-ICT-EX-2009:177, October 2009 https://urn.kb.se/resolve?urn=urn%3Anbn%3Ase%3Akth%3Adiva-91489 Links to an external site.

Transcript

[slide458] And now Opticall, AB. There are a whole set of master's theses, one of them done by Max Welts, who later went on to work in a number of companies working with Voice over IP. And basically the company's model was very simple. Think of a company that has sales persons out in the field with their phones. And there's some home office here, and they're connected to the internet. They said, hmm, what can we do to make it so that we can reduce the cost of our mobile services? Well, they said, we can put a little box in that has a series of telephone boards in it, for different cellular companies. And we can equip one with a SIM card for company A, company B, company C. And now, if one of our people in the field wants to make a call, what do we do? They call to us, via a particular cellular network they're using. So let's say this person has SIM for company A. So this goes through company A's network, delivers the call here. Now what happens if they want to speak to someone who has, let's say, SIM card B, for another cellular operator? What do we do? We use our card here, that also has a SIM card B, so that this call goes via operator B. What's the advantage of that? Well, it turns out that there are special prices for calls from one customer of operator A to another customer of operator A. And there's a different price for calling from operator A to operator B's customer. Anyone see where this is going? This way, we always use the best and cheapest, which is the same operator as the user is using. And then here, we bridge the traffic from one to the other as a VoIP call. That lets us reduce our prices for our telecom services. How can we reduce it even more? Well, one of the methods we could use is the fact that instead of placing the call from these devices, we place all of our calls from this device. Now, what's the advantage of placing all your calls from the company going out? Anyone know? [student answers: better pricing] Volume pricing, right? The bigger your call volume, the better pricing you can get. So, by making all of the traffic always originate outward, we have aggregated all of our call volumes into a small number of accounts. But how does this person make a call? Well, they build a little dial-over data application where what you do is when you start dialing your number, it looks at that number and then sends that via data service to a server that's running here, which then proceeds to call you back and call the other party by the most cost-effective means possible, and then bridges the two calls together. Yes. So, if the price from A to B is expensive, and B to A is expensive, we want to reduce that, and if the price for A is a function of volume, then we want to up our volumes. This does all of those things. That was a very interesting set of theses, and a number of students looked at how do you really take advantage of this, and how do you scale these services. I should also say, well, I'll save that for later. Any questions about that? So, we see that for services, we can build all kinds of interesting services, just given the basics that we already understand.