Imprimir Republish


In search of reliability

Networks gain security with new equipment

When the first networks were installed in the universities and institutes of São Paulo, the process was simple. A telephone cable would be passed along points close to where the interested parties were. For each point on the network, the cable would be cut and a connection would be set up with the computer. All the computers were connected amongst themselves, as if on a clothesline. If one of them had a problem, like a short circuit in electricity, the whole network would go down. This would not cause any great surprise. The breakdowns in the networks were frequent, and, when they happened, the work that was being carried out would be lost. Not that the losses were that great: the networks were too small. In one of the pioneers, at the Institute of Mathematics and Statistics of the University of São Paulo (USP), for example, the computers on the network, installed in 1992, were all in the same room.

The situation has changed a lot. Today, all USP’s more than 500 buildings, for example, are connected by a network that is reliable, secure and, above all, fast. In the place of the old coaxial cables, much more secure cables are used, with a technology known as unshielded twisted pairs, or UTP. In some cases, the cables have been replaced by optic fiber, even more stable. Each computer is connected directly to a hub. If there is a problem, this will not interrupt the rest of the network. The hubs, in turn, are connected to a piece of equipment from which the cables that make the external connections come out.

Digital communications
Professor Fernando Paixão, of Unicamp’s Institute of Physics and a member of FAPESP’s coordinating body for information technology, compares the situation at the time that the program was launched to a town where electricity first arrives. “The posts take the electricity to the doors of the houses, but, to use it, every house needs to do the installation, laying out wires and installing the sockets”, he says. It was more or less what happened at the universities. Each institution set up its own network, profiting from the arrival of communications. At the time, according to Paixão, it was already foreseen that digital communications would quickly replace telephones and telex machines. Hence the unanimous recommendation of the information technology commission for FAPESP to give priority to the installation of networks in its infrastructure projects, which started in 1995.

Milton Kashiwakura, an advisor from FAPESP’s Academic Network in São Paulo (ANSP) network, who took part in the installation of USP’s network, recalls that the job called for a lot of effort to monitor it. “Each company under contract had its own standards, and it was necessary to lay down rigid rules, to be obeyed by all”, he says. When the contract ended, each company would only receive its money after a rigorous inspection. In the case, for example, of a connection by optic fiber, the cable cannot be stretched too much. If this happens, it will never work properly. “You can use the best material in the world, but if the installation is not done well, it all has to be thrown away”, warns Kashiwakura. There are other precautions. UTP cables, for example, have to be laid far from the electrical wiring. The wiring creates magnetic fields, and the cable, made of copper, suffer when they are too close.

Even so, copper cables are still much in use, particularly in networks inside buildings, where they run through metal conduits installed along the walls. This is due, above all, to cost savings. The most modern cables, of categories 5 and 6, can support the current traffic perfectly well. Meter for meter, the prices of UTP cables and optic fiber are equivalent. The difference lies in the sockets that connect the computers to the network, much more expensive in the case of optic fiber, because of the special material needed for this kind of communication, and in the modems installed inside the computers themselves. In an optic fiber connection, the modem costs about four times.

Indoor work
Nevertheless, the difference starts to be worthwhile in certain cases. One of them is distance. It is consensus amongst the technicians that, for distances over 100 meters, UTP cables cease to be advantageous, because they need more equipment for transmission. The tendency is therefore for them to be used in indoor work, leaving outdoor work to fiber. Connections by fiber are also preferable when they pass through surroundings with a lot of interference, such as that caused by electric motors working. Used outdoors, fiber has another advantage. As is works on the basis of light, if the network is struck by lightning, the discharge will not reach the point of burning out computers and other equipment, as can happen with copper cables.

There is yet another question. Fiber allows for much higher speeds. This is becoming more and more important in a network. The technicians say that cables of categories 5 and 6, the current market standard, will support the needs foreseen for the next few years. But networks set up with category 3 cable, like the first ones in the United States, are now calling for replacement. The cost is high, but not frightening. “If the prices of automobiles came down as much as the prices of computer equipment, we could buy a car today for R$ 1”, Paixão jokes.

The need for more capacity has an explanation. To carry out a surgical operation at a distance, for example, the usual networks are insufficient. They do not allow work to be done in absolutely real time, which may be essential in more complicated operations. Paixão points out that, in parallel to the formation of local networks, FAPESP has invested a lot in the development of the ANSP network, which links universities and institutes amongst themselves and to the rest of Brazil and abroad. The ANSP 2 network, now being installed, will be even more rapid, and will be capable of eliminating a few bottlenecks that still exist.

Isolated investments
Evolution is part of information technology. That is why it is natural for networks to evolve. The university local networks today support up to 100 megabits a second without any problem, which is a good standard, according to the technicians, for current needs. “But if traffic becomes more intense, the wires will not be able to stand it”, states Paixão. “The situation would be like using an ordinary wire to connect an electric shower to the electricity supply”. Paixão, however, sees this as a much less critical situation than the one that there was before the first investments under the infrastructure program. “It can be resolved with isolated investments, with funds financed from the proceeds of the research carried out, using the technical reserves”.

A more complete change, however, may come from the Information and Development Technology for the Advanced Internet project (Tidia), recently approved by FAPESP’s council. “This is the next step for the Internet”, says Antônio Carlos Ruggiero, responsible for the installation of USP’s network in São Carlos and an advisor to the team that is studying the project. The purpose of the project is to stimulate the development of advanced technology in the Internet area. “Today, there are no more worries about Internet 1”, says Ruggiero. “It is now well established. But the applications for Internet 2 are still not available. There is a lack of technology, a lack of knowledge, and a lack of development in the area of research. This is what the program has to encourage”, he adds.

This venture follows a world-wide trend in the computing area, and it will include researchers from all over the world taking part. “It is something that is entirely new, less committed to production traffic than Internet 1”, says Ruggiero. With the new system, researchers will be able to carry out various experiments that today would be interrupted or would jeopardize the flow of data that runs over the networks. It is research, for example, in which the network has to be interrupted to install or to change equipment. These tests may give rise to novelties as impressive as those that a little over five years ago began to change the possibilities open to researchers in São Paulo.