Will VoIP Kill the PBX?

gManZboy writes "Following up on their last VoIP article, Queue just posted "Not Your Father's PBX?" from Jim Coffman at Avaya Labs. Looks like the PBX may survive, but it's going to have to evolve considerably. I guess eventually corporate telecom goes away as a kind of island in the MIS dept? Maybe that's already happened?"

Comments

Re:Bias

[gregarican]

I don't understand your post. If you are saying that Avaya is only traditional telco, they have been selling VoIP equipment for over three years now. The last World Cup matches had the entire setup using VoIP and WVoIP services provided by Avaya...

Evolution, not revolution

[jd]

Telephone systems have been evolving, from the very beginning. Originally, switchboards were manually operated. I'm not just talking for hotels, but for major cities. That worked, because not many people had phones.

When the manual switchboards were replaced with analog/mechanical switching, it did cause some changes to the system. You couldn't just speak into the phone and be connected, you had to manually dial a number. That particular change cut both ways - it wasn't quite so convenient, but it was less prone to error and it did allow more people to have phone service.

Then, along came digital exchanges. Early digital exchanges had numerous programming bugs (to be expected) but these have now been largely ironed out. Digital exchanges are faster, more reliable and easier to maintain, but the changes haven't been really visible to end users.

Now, we're moving into the VoIP era. Instead of dedicated lines and switched circuits, we're looking at a packet-based system with routing. VoIP reduces the resources needed (it can - in theory - make use of any spare network capacity between the two points to be connected) and it simplifies some of the more complex types of call. (Multi-point phone calls over IP are as simple as a multicast, for example. Over a switched circuit, it takes a bit more effort.)

Will VoIP kill the PBX? It depends on how you define the PBX. If you think of the PBX as a person manually connecting you, then the mechanical relay exchanges killed the PBX. If you think of it as merely the mechanism (human or otherwise) by which two or more people can be connected, then routers become the "new" PBX.

Of course, true VoIP will only be possible with a migration to IPv6. There are simply too many phone numbers, which would need an IP address, to use IPv4. Also, IPv6 headers are simpler, which makes routing more efficient. This makes the complexity of routing over much more complex networks possible. Finally, IPv6 doesn't fragment, which means that packet garbling should be less common.

It'll also require much higher bandwidths. The Internet is just too crowded to support much in the way of high-quality audio traffic. Packet loss is a shade too high, and latencies need to be cut. Your computer can quite comfortably handle uneven packet transmission, but the human ear can't. To fool the ear, you need much smoother traffic flows.

Smoother flows mean you need lower hop counts. This means the backbone needs to be better connected. There's been a tendancy for backbones to move towards the simplest possible layout. That's great for economics, but it means that paths are maximised. Not good for VoIP. It also means that if there's any outage, there's unlikely to be an alternative route, which means that network segments will be disconnected. Also not good for VoIP.

Telephone companies will be around for a long time, because they're about the only ones with the infrastructure and capital to build the highly connected networks required for VoIP. This is not a time for telephone companies to be concerned, this is their golden opportunity to demonstrate their continued relevence.