Packets and Pieces of String

April 2002

Convergence is a word you see a lot in the IT and telecommunications press, apparently it is inevitable, or maybe it has already happened, alternatively it could just another bit of tech stock hype? In this context convergence is a term which broadly encompasses the coming together of data and voice based communications. The first significant manifestation of this is the Internet itself which is a data network which, because it can run over the existing telecommunications infrastructure, has spread into hundreds of millions of homes and businesses in just a few years.

A conventional telecommunications network consists of permanent connections between physical premises and central collection points, a piece of 'string' connecting your home to the exchange, and then much larger bundles of connections between one exchange and another. When a telephone call is made these physical connections are joined up and there is in effect a continuous physical link between two points for the duration of the conversation. This type of connection is ideally suited to supporting the continuous flow of a conversation where, provided overall quality is adequate, a little variation in sound quality is no problem.

Data networks by contrast are designed to send finite chunks or 'packets' of data where the absolute integrity of the data is the most important consideration. In this type of network files such as pictures, web pages, or even digitised conversation are broken up into a series of small packets and sent to the destination where they are carefully reassembled so that the original file can be reproduced exactly. Individual pieces of the jigsaw may travel by quite different routes depending on the traffic, (network traffic in this case, but a comparison with road traffic would be surprisingly apt). The recipient will only get access to the file once it has been fully reassembled and checked.

So data networks break information up into packets and fire them into the ether to be reassembled on arrival, whilst voice networks link two points continuously for the duration of a call; and each is optimised to suit a different type of communication. However things are no longer that simple, the Internet and mobile phones have mixed things up considerably.

The internet is a data network and IP, or 'Internet Protocol', is a specification for how to send and receive packets of data, but the internet also supports continuous connections where these packets can arrive in the same neat order they were sent in. For those who like acronyms this is what TCP or (Transmission Control Protocol) provides, hence the combined use of TCP-IP to describe the technology underlying both the Internet and also the majority of corporate data networks these days.

Mobile phone networks are also packet based because they work by allowing lots of users to share the same radio frequencies. Standard GSM networks are however optimised for voice traffic. Whilst newer network standards such as UMTS aka 3G and GPRS (2.5 G) are actually much more like data networks which also support voice.

What all of this is leading to is the simple fact that all networks are becoming more and more like the internet which is a packet based data network which also happens to support point to point connections. This opens up some very interesting possibilities and, particularly for telecommunications companies some knotty business issues. Witness the gradual evolution in the way internet connections are paid for; five years ago virtually everyone connected to the internet using a conventional telephone line and paid two bills, one to the phone company for the individual calls made and one to the ISP for the provision of the services at a flat rate.

Now, by contrast a majority of business users and a growing minority of domestic users are permanently connected to the Internet through leased circuits or 'always on' dial up services. The important point about these connections being that they are paid for through a fixed annual charge with no (separate) call charges.

Meanwhile a technology called Voice over IP (VoIP to it's friends) has been gradually gaining acceptance. VoIP exploits the fact that the Internet can emulate the 'pieces of string' involved in conventional telephony and, on a good day, provide a global telephone network on which calls are, in effect, free! So what's the catch? Up to now the main issue has been the quality and reliability of the calls made this way. Also, from a domestic users stand point making telephone calls over the internet requires extra equipment and a fair amount of messing about (for want of a better description). Consequently the idea of making telephone calls over the Internet is regarded by many as a fringe activity beloved of Internet bores rather than a serious corporate option.

As with so much in this industry this is changing very rapidly as the technology matures. A combination of trends is making the prospect of merging voice and data communications look more and more attractive certainly from a business perspective.

For example, a move to integrated IP based telephony brings it within the skill set of staff employed to maintain data networks. For companies with fixed data networks between sites adding voice traffic to the same infrastructure can provide a fixed cost alternative to the variable cost of calls made through the telephone company.

For domestic users the increased adoption of 'broad band' Internet access services such as ADSL, or cable modems also provides opportunities to add free or low cost telephone calls to the list of services offered through the internet. There are already plenty of companies about which offer reduced cost long distance calls accessed through free phone numbers, and there is currently a huge surplus of capacity on the international data networks as a result of the bursting of the Internet and telecommunications bubbles. Put this capacity together with the expertise of the budget telephony providers and we have a global market for low cost telephony which the individual can tap into through their home Internet connection.

All of this leaves the phone companies with an interesting set of challenges, on the one hand there is a huge threat to traditional call charges, whilst on the other side there is likely to be continuing demand for increased fixed infrastructure from business and broad band services from the consumer. Meanwhile on the mobile market the industry itself would like us to move on another step in the way we do business with them, to paying for the volume of data we send, rather than for the connection itself. This is a very significant change which will require a considerable change in our mind set from watching the time we spend on line to thinking about the volume of the files we are downloading. In the context of the telephone it does however open up the interesting possibility of each party to a conversation paying for their own half of the conversation, imagine being able to 'go dutch' on the phone!