IP based data+voice infrastructure

Transcript

[slide35] So if we look at the kind of infrastructure you can get, we can have these E1 to PSTN connections. We can connect them now to a LAN. We can connect devices to that. We could do that inside a workstation. We can even do it across a telephone line, so traditional dial-up modem, to your home. What's the advantage of that? So the next gentleman in the back. You, yes. So why would you want to, if you had a dial-up modem and you're sitting there at home working on your dial-up modem, why would you want to have voice-over IP? [student answers: Because it's more convenient for communication and more economical than a traditional way.] Well, but that would be true if I had a separate voice-over IP system. The problem is, I'm using my fixed line already for my computer to communicate. Years ago, I used to have modem calls that lasted for months. No one could call my phone, right, because my phone line was permanently engaged, connected to the modem server, modem pool on the other end. So anyone calling me couldn't possibly get through. But if I mixed VoIP traffic on top of my data traffic, what happened? I'd get a little pop-up window saying, do you want to accept this call? If you would click, boom, and now I could be talking at the same time I was doing my data communications. And Theo Kanter and some other people built a system to do this called Phone Doubler. And the idea was, it gave the home user the impression as if they had two phone lines, one for their data service, one for their voice calls, but they were really just sharing the same copper. So why did the operator care that I couldn't receive any voice calls? They were getting paid my monthly amount for my phone. So why would the operator want to introduce Phone Doubler? [student answers: Maybe they wouldn't receive the customer support.] No, much simpler reason. Can you help them out? More money, right? Because if a call doesn't get delivered as a voice call, can you bill for it? No. So they saw all of these calls trying to get there that weren't being able to be answered as lost money. So by giving the customer Phone Doubler, they just increased their income.