Multiplex communications – Wide area network – Packet switching
Patent
1991-12-13
1993-08-17
Safourek, Benedict V.
Multiplex communications
Wide area network
Packet switching
340826, H04L 1256
Patent
active
052375650
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a multiple path, self-routing switching network for switching asynchronous time division multiplex cells.
A switching network, in its widest structural definition, comprises input ports to which are connected input connections, output ports to which are connected output connections, switching elements disposed between these input ports and these output ports, arranged in one or more stages and interconnected by links. The input ports of the switching network are associated with the inlets of switching elements of a first stage, while the output ports are associated with the outlets of switching elements of a last stage. The outlets of the switching elements of said first stage are connected by links, possibly by means of intermediate switching element stages, to the inlets of the switching elements of said last stage. The links generally comprise one or more independent connections, each connecting an outlet of a switching element to an inlet of another switching element or the same switching element.
Such a switching network is said to be a multiple path network when it offers more than one switchpath between any one input port and any one output port. In this case, identification of an input port and an output port is not sufficient to determine a path from one to the other. There is still a choice to be made between the multiple paths offered by the switching network between this input port and this output port.
Such a network is said to be self-routing, in the broadest sense of the term, when it is such that a switchpath is determined in a switching network not only by means of routing information containing the implicit or explicit identification of an input port and that of an output port of the switching network, but also by a routing decision specific to the switching network.
The self-routing facility introduced in the switching network thus provides an independent means for solving the routing problem posed by multiple path networks when the routing is defined only by identification of an input port and an output port.
Multiple path, connection-oriented, self-routing switching networks are well known in synchronous time division multiplex channel switching or circuit switching. In such networks, the connection setup or routing process is accomplished once, at the beginning of a call, and determines a switchpath the elements of which, initially free, are then occupied by the call, and therefore become unavailable for other calls. The switchpaths set up therefore cause a risk of blocking through a lack of channels when searching for a new switchpath. The switching process applied in these known switching networks generally encompasses all or a major part of the switching network. It is therefore complex and requires a relatively long time lapse, in terms of individual control operations to establish the connection. On the other hand, this time lapse is very short, compared with the duration of the call and is not therefore prejudicial to the communication efficiency of the switching network.
Cells, also called packets, are units of digital information comprising in particular a tag containing information for identifying the destination of the cell and call data.
Cells are of fixed length or variable length. In the latter case, the cell is transferred in the form of an uninterrupted sequence of a number of relatively small fixed length sub-cells enabling internal transfer, storage in memory or in registers and sub-cell processing functions to be optimised.
In an asynchronous time division multiplex cell transmission system, the cells of several calls, transmitted over the same connection, follow each other in any order and cells relative to a particular call are transmitted at irregular intervals.
Taking into account the characteristics of asynchronous time division multiplex cell transmission, an asynchronous time division multiplex cell switching network is generally a switching network constructed to switch such cells individually, in such a way that a switchpath is foun
REFERENCES:
patent: 4760570 (1988-07-01), Acampora et al.
patent: 5032837 (1991-07-01), Yoshifuji
J. S. Turner, "Design of a Broadcast Packet Switching Network", IEEE Trans. on Communications, vol. 36 No. 6, Jun. 1988, pp. 734-743.
J. H. Degan, et al, "Fast Packet Technology for Future Switches", AT&T Technical Journal, vol. 68 No. 2, Mar. 1989, pp. 36-50.
Mund & Guibaly, "A 2.times.2 Switching Element for Broadband ISDN", IEEE Pacific Rim Conference on Communications, Computers and Signal Processing (Victoria BC), Jun. 1989, pp. 620-623.
Henrion Michel A.
Verhille Henri
ALCATEL N.V.
Safourek Benedict V.
LandOfFree
Multiple path, self-routing switching network for switching asyn does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multiple path, self-routing switching network for switching asyn, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multiple path, self-routing switching network for switching asyn will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2250106