Communication networks

Details Communication networks Communication networks

1985-06-07

1988-03-22

Olms, Douglas W.

Multiplex communications

Wide area network

Packet switching

370 89, H04J 302

Patent

active

047333910

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

This invention concerns communication networks, and relates in particular to novel network topologies and apparatus therefor suitable for data communication between computers.


THE BACKGROUND

Although means for connecting large, mainframe, computers both to their own equipment--terminals, tapereaders, disk stores, printers, and so on--and to other large computers have been known for many years there has, following the introduction of minicomputers and (especially) micro-computers, been a very considerable resurgence of interest in networked communication systems (networks) interconnecting not only all sorts of computers and their ancillary equipment but also computer-driven devices such as word processors and process control apparatus. Indeed, this interest extends to the use of networks to carry all sorts of information signals, including voice and picture information (usually in digital form); for convenience, however, this Specification refers hereinafter to networks in terms of computer networks, without any intention of excluding other types.
One type of new network is designed primarily for use in connecting machines within a small area--an office, a building, or perhaps several buildings in the same locality--and so is known as a "local area network" (LAN). Though the many available types of local area network are usually different from the older networks used with large computers, there is no reason why they should not incorporate one or more large computers, and indeed it is generally the case that they do.
The hardware--the actual apparatus--of any computer network will in general comprise a number of stations joined to each other in one of a small number of topological ways by the network connecting medium (which is commonly a twisted-wire pair, a coaxial cable or an optical fibre). At each station there will normally be an interface unit connected between the network medium and one or more computer or computer peripheral device. Just how the coupling between the interface unit and the connecting medium is actually made depends to a large extent upon the topology type used for the network (star, bus and ring topologies are discussed further hereinafter). In ring networks, the variety with which this invention is primarily concerned, each interface unit is coupled into the network by a specialized switching device known as a repeater unit (because it receives signals from the network ring on its IN side, passes them, if appropriate, to the attached interface unit, and then "repeats" the signals to the ring on its OUT side--usually by generating a copy that it transmits on to the ring.
A network needs both the apparatus and some form of unified control system so that the various hardware components can actually understand the signals each transmits to the others. While it is the job of each interface unit to convert signals on the network into a form immediately useable by the equipment connected to that interface (and vice versa), the task is only really possible if the network signals are in some sort of standard form, in accordance with rules defining how the entire system is to operate. These rules are referred to as "protocols", and there are a number of types of protocol, these together governing all aspects of system operation. Both the hardware specific to the network itself and the protocols governing how the whole system should function depend to a very large extent upon the topology of the network--that is to say, upon the manner in which the individual components are joined one to another in space. Local area networks--for the most part the term "network" is used hereinafter to mean a local area network, though the invention extends to other kinds of networks--generally have one or a "combination" of three main topologies, known as the star, bus and ring topologies.


PRIOR ART NETWORKS

Networks with a star topology are the older sort of networks. Like the telephone subscribers connected to a single telephone exchange, star networks have a central switch

REFERENCES:
patent: 4032893 (1977-06-01), Moran
patent: 4393497 (1983-07-01), Cantwell
patent: 4399531 (1983-08-01), Grande et al.
Grnarov et al, "A Highly Reliable, Distributed Loop Network Architecture," Digest of Papers FTCS-10 (Oct. 1-3, 1980), pp. 319-324.
Goyal et al, "Reliability in Ring Networks," Compcom 82 (Sep. 20-23, 1980), pp. 444-453.

Affiliated with

Also associated with

Rating

Communication networks does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Communication networks, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Communication networks will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-446420