Are you still using a conventional desktop phone at your workplace which is connected to a conventional telephone outlet? Hardly likely. You are also probably already working with a modern IP set or even a so-called soft client. For a huge technological change is taking place, where pure telephone networks are disappearing and instead, telephony is being shifted to the computer network. This change also calls for a new technology for audio communication, which has become known as Voice over IP. This article sheds light on the key aspects of this modern technology.

What is Voice over IP?

The term Voice over IP (VoIP for short) refers to any transmission of voice communication over IP networks. There are many different forms of this. For example, services such as Skype or WhatsApp, which enable phone calls to be made between their clients over the Internet. Or special Internet telephony service providers where you can register individual devices or soft clients. Or telecoms providers which connect the telephony systems of companies to the public network via SIP trunks. And companies which have decided to replace their conventional telephony with VoIP. And many more... 

The principle

In contrast to conventional telephony, where dedicated telephone lines are being used for the transmission of calls, with Voice over IP – as the name suggests – , transmission is over a computer network. Permanent connections are, however, not intended on this network. Instead, for this reason, individual IP packets must be sent, which transport the required content. And this is also the major difference to classic telephony, where there is a permanent connection between the parties during a call. With VoIP, the call data is digitized and packed in individual IP packets. Like all other packets which are otherwise floating around the network, they are then transmitted to the correct remote station, where they are in turn converted into voice.

Different protocols are used in this case for establishing the connection and for transmission of the voice data. First, the correct remote station must be found and the call set up. This is usually currently done using the so-called SIP protocol, but others also exist, e.g. H.323. These signaling protocols take care of all aspects of the call setup: searching for the required party, informing his device to ring and signaling the ringing to the caller. During this process, the two devices also agree on the details for transmitting the call data, including the protocol to be used and the compression algorithm (codec).

If the party searched for accepts the call, the connection is put through, and the data is transmitted using the negotiated protocol. This is usually done with RTP (Real-Time Transport Protocol), but the logical signaling connection is retained. This is namely still needed at the end of the call to terminate the call properly for both parties (and all routers on the line).

What does Voice over IP offer?

You can of course make phone calls with Voice over IP. But that's not all. VoIP offers many additional features which are not available with conventional telephony. With soft clients, telephony is connected to a computer. This enables chats for exchanging text messages. And file transfer options are available. And also desktop sharing. And video. And conferences. And online meetings.

The improved voice quality must also be mentioned, and last but not least, mobility. For with a soft client you can log in from anywhere and still be reached, e.g. in the home office, and even with your usual phone number.

All these features are actually indispensable for our daily (office) routines.

And the costs?

These are also in the green, for

1. there is no need for costly investments in separate telephony networks.
2. if Voice over IP services are obtained from the cloud, the procurement and operation of proprietary telephone systems are not necessary.
3. call charges are also reduced, for all the calls which are not made using the public telephone network are free of charge.

In comparison, the costs for operating a Voice over IP cloud solution are minimal, and all things considered, even using a proprietary IP telephone system results in considerable savings. 

Migration

There are two methods of switching from conventional telephony to Voice over IP. Either the entire telephony is changed at one go, or in stages, with the old telephone system continuing to operate until the end. So, for example, a dozen telephones are replaced every night.  The latter method is common especially in larger companies, if only because of the complexity. For example, issues such as availability, call handling, emergency calls and the handling of shared phones, elevator phones, faxes and wall-mounted telephone sets need to be discussed. And last, but not least, it is often impossible to replace thousands of sets overnight.

For smaller companies, on the other hand, it is often simpler to change over to IP telephony almost overnight, although of course this also raises the question as to whether the old system should continue to be operated as a fallback until the new system has become established.

Conclusion

The adoption of Voice over IP in modern companies is in full swing, for the use of VoIP offers companies major benefits that they don't want to miss out on. It should also be mentioned that nearly all well-known telephone manufacturers have jumped on the VoIP bandwagon and only offer conventional telephony to a limited extent. It is therefore only a matter of time until only IP telephony will be available.