Answer to Question #90172 in Computer Networks for Shivam Nishad

Question

What are the two classes of computer network architecture ?

Answer 1

Classification of computer networks as data transmission

If to look in general, there are two types of technology of transfer:

• broadcasting networks;

• networks with transfer from knot to knot.

Broadcasting networks

Broadcasting networks possess a uniform communication channel, shared by all cars of the network. The short messages called in certain cases by packages which are sent by one car receive all cars. The address field specifies in a package to whom the message goes. When receiving a package the car checks its address field. If the package is addressed to this car, it processes it. The packages addressed to other cars are ignored.

By way of illustration imagine the person standing at the end of a corridor with a large number of rooms and shouting: "Watson, go here. You are necessary to me". And though this message can be received (is heard) by many people, only Watson will answer. The others just will not pay attention to it. The announcement at the airport suggesting to all passengers of flight 644 to approach an exit number 12 can be another example.

Broadcasting networks also allow addressing a package at the same time to all cars by means of special code in an address field. When the package of such code is transferred, it is received and process all cars of the network. Such an operation is called broadcasting transfer. Some broadcasting systems also give an opportunity to send messages to a subset of cars, and it is called multiple-address transfer. Reservation of one bit for a sign of multiple-address transfer can be one of the possible schemes of realization of it. The remained n-1 of categories of the address may contain a number of groups. Each car can "be signed" for one, several or all groups. When the package is sent to a certain group, it is delivered to all cars which are members of this group.

Networks with transfer from knot to knot

Networks with transfer from knot to knot, on the contrary, consist of a large number of the connected pairs of machines. In the network of this kind to a package to reach the destination, it is necessary to pass through a number of intermediate machines.

Often at the same time, there are several possible ways from a source to the recipient, therefore, algorithms of calculation of such ways play a very important role in networks with transfer from knot to knot. Usually (though there are also exceptions) the small, geographically localized in one place networks use broadcasting transfer whereas in larger networks transfer from the knot is applied to knot. In the latter case, there is one sender and one recipient, and such system is called sometimes the unidirectional transfer.