What is VOIP? (Voice over Internet Protocol)

This article introduces the reader to the basics of VOIP, or Voice Over Internet Protocol. The VOIP tutorial attempts to answer, in layman's terms, common questions such as how does VOIP work, what are the benefits and drawbacks of VOIP, and what are the infrastructure requirements to implementing a VOIP solution.

Historically, phone calls used a network made up of copper wires and switches that created a circuit between the caller and the person being called. This technology was mature and fairly reliable, but inefficient. Thousands and thousands of copper wires had to be run from house to house, neighborhood to neighborhood, city to city, country to country - and continent to continent! There had to be a pair of copper wires for every call that needed to go from one place to another.

The modern solution to this problem uses data networks that allow information - like your audio conversation - to be broken up into packets and shipped over a shared network link. This is much more efficient for many reasons, but we'll talk about two of them here. The first is utilization. If your neighbor's teenager calls his girlfriend and they hold the phone in silence, very little of the phone system's capacity is actually used. In the old, circuit-switched scenario, two copper wires are used for a phone call, whether anyone's talking or not. The second efficiency is one of infrastructure. Instead of building two parallel networks, one for data and one for voice, we can unify the two networks and create a single network that costs considerably less to build out than the dual networks we were building before.

This can scale to businesses today. If you use a PBX and VOIP in your business, you cable for data exclusively. You increase the size and capacity of your data network, but maintaining one network with more bandwidth is less expensive than maintaining two networks. Furthermore, if you have multiple offices and you maintain a data link between them, you can keep all of your phone service 'inside' your network, where you control configuration and security. Your phone service will go to the public phone network only when you connect a call to a phone outside of your VOIP network.

Another business benefit of VOIP over typical phone solutions is administration. The number is assigned to the phone, not the wall jack, so you issue a phone to an employee, and it works wherever they plug it in. With modern VOIP PBX solutions, you have significant administrative control over things like who your employees can call, when they can call, how long they can talk, who can call them - the range of control can be amazing, depending on your vendor.

All of this results in a lower overall cost of ownership for VOIP in many cases. This isn't a generic result, and there are many variables, but for many offices VOIP can cut costs dramatically. But you must remember that this also places your voice services on your data network. Failure of a network element isolates both data and voice service. This is generally uncommon, but you cannot ignore the fact that losing a switch, for instance, will make it impossible for people on that switch to call and report the outage.

Another thing you have to consider is whether your data network is robust enough for the data load your VOIP service will place on it. If you have high latency or low throughput segments in your network, VOIP will make this painfully clear. Make sure you understand the performance of your network and the bandwidth requirements of your VOIP solution. A company that has only a single voice call active at a time, on average, has completely different VOIP and bandwidth needs from a company that does telemarketing, for instance, or a customer service call center. Make sure you discuss these issues with any prospective VOIP vendor you work with, so that you don't find out after you implement your VOIP solution that you must now upgrade your data network to support it.

VOIP is the future, there's little doubt about that. Data networks will subsume (already have, really) voice communication, and switched circuits are only virtual even now. It's a technology that can be of great benefit to many companies, and if you're thinking of putting in a PBX of whatever scale, it's certainly a solution you should consider, and if you keep all of the requirements in mind, VOIP might just be the right solution for your company now, rather than tomorrow.