NZ286353A

NZ286353A - Telecommunication network exchanges combine data into blocks each containing only data for a single destination exchange

Info

Publication number: NZ286353A
Application number: NZ286353A
Authority: NZ
Inventors: Gert Eilenberger; Stephan Bunse
Original assignee: Alcatel Australia
Priority date: 1995-04-18
Filing date: 1996-04-11
Publication date: 1997-03-24
Also published as: KR960040047A; AU5068296A; EP0739113A2; TW312876B; CN1139326A; AU710096B2; CA2174402A1; JPH0923236A; DE19513564A1; EP0739113A3

Description

<div class="application article clearfix" id="description"> 28 63 E 3 Priority Dalo(s): Comploto Specification < ited: Class: (6) Publication Date: P.O. Journal No: HHKCKX NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION "METHOD OF OPERATING A TELECOMMUNICATION NETWORK" WE, ALCATEL AUSTRALIA LIMITED, CAcH °°S 3^) A Company of the State of New South Wales, of 280 Botany Road, Alexandria, New South Wales, 2015, Australia, hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: 28 6353 This invention relates to a method of operating a telecommunication network having a plurality of network-access exchanges and a plurality of transit exchanges, with each network-access exchange connected directly or via an arbitrary number of transit exchanges to every other network-access exchange and to a plurality of network-access channels. In today's hierarchical telecommunication network a separate transmission channel is switched for each connection between a first and a second subscriber via several exchanges or network nodes. This message switch can also use different channels e.g. a synchronous time-division multiplex channel or a virtual ATM channel. In each exchange there must be a bit-accurate access to each individual transmission channel. This becomes increasingly more difficult with increasing transmission speed. In optical transmission technology one can soon expect transmission speeds of more than 10 Gigabits/s. To be able to process such data streams, particularly for address evaluation and for time-position conversion, they are divided into partial data streams by demultiplexing, and converted into slower data streams by serial-parallel conversion , they are therefore ultimately very strongly paralleled. On the other hand, all prerequisites are given to boost optical data streams, to switch them between two paths or to con art them between two frequencies or wave lengths. According to the invention there is provided a method as claimed in claim 1, wherein the user-data blocks and the address-data blocks assigned thereto are transmitted ovar separate, parallel transmission paths, and wherein the assignment follows from the relative temporal occurrence and the assignment of the transmission paths. According to a further aspect of the invention there is provided A network-access exchange, particularly a subscriber exchange, having a plurality of ports for network-access channels, particularly subscriber lines, and at least one port for a trunk to a transit exchange, wherein means are provided for combining user data coming from the network-access channels into blocks such that each block contains only user data intended for network-access channels of a single further network-access exchange, the user data in the respective block being assigned control data to assign them to a selected network-access channel at the destination, the means being further adapted to assign a block containing address data to each block containing user data, means being provided for transmitting user-data blocks and address-data blocks via a port for a trunk to a transit exchange, and wherein means are provided for receiving user-data blocks and address-data blocks from a port for a trunk and for outputting the user data contained in said blocks, based on the control data assigned thereto, via the port assigned to the selected network-access channel. According to a still further aspect of the invention there is provided a transit exchange having a respective port for each trunk to another exchange, wherein means are provided for evaluating address-data blocks coming form a trunk and for switching said address-data blocks, together with user-data blocks assigned thereto, to another port for a trunk. The basic idea is, to mesh all subscriber exchanges of the network by virtual paths. Each virtual path is implemented with a sequence of "supercontainers" whose contents are transmitted transparently. Only the control information accompanying each of the "supercontainers" is standardised and evaluated. Where this network does not reach to the subscriber, the network- access exchange is available instead of the subscriber exchange. Here, the subscriber exchanges are connected with each other as the individual subscribers are with the ATM (Asynchronous Transfer Mode). Data packets are formed, here called supercontainers, which comprise a packet header and an information part. The information part is switched through transparently, it can contain, for example, a plurality of ATM cells which come from subscribers in the area of the output-subscriber exchange and are intended for subscribers of the destination subscriber exchange. The packet header carries the information required to guide the corresponding supercontainer to the destination exchange. The transmission speed in the packet header can be lower than the speed in the information part. This makes it possible on the one hand, to transmit the highest amount of data in the information part, and on the other to process the control information online in the packet header with little expenditure, in each exchange stage. It is not mandatory that the packet headers be connected with the corresponding informaiion part in the manner of ATM cells. Other types of assignment are possible. Provided the information parts are not to be stored temporarily, it must at least be ensured that the packet headers or corresponding address data blocks precede the information parts as the user-data blocks. With the desired optical transmission several parallel transmission paths are used by means of wave length multiplex. It is possible to divide one of these transmission paths, i.e. a wave length, into time slots and to assign each of these to one of the remaining transmission paths. Each of the information parts is then transmitted with one wave length, the corresponding packet headers by time-division multiplex on one further, common wave length. It is also feasible to each combine one pair of broadband and narrow band transmission channels with separate wave lengths and to use these on the one hand, for information parts and, on the other for packet headers. The use of separate transmission paths for packet headers and information parts can simplify the evaluation of addresses and other control data. However, it must then also be ensured that these control data are exchanged separately and assigned explicitly. A somewhat larger, even if unique, distance between packet header and information part is also feasible, to match processing speed in the exchanges and high transmission speed. The distance can, for example, be filled by the information part of a preceding packet and the packet header of a succeeding 20 £ O Uw J packet. The configuration of the exchanges according to the invention and the v operation of the network according to the invention have the advantage, that the serial user data stream can be retained, even at extremely high transmission speeds. Time-position conversions are not required within the network, if it is possible to switch to and alternative path at any position. This makes it suitable for an all optical exchange. A further significant advantage is that the bit-accurate synchronisation is not required. In principle, one could waive all synchronisation if sufficient alternative paths were always available. The information parts could also be of arbitrary length. The available capacities are however better utilised when fixed time slots are used. It is however sufficient to integrate one supercontainer into this time slot such that a guard time is maintained between the preceding and the succeeding supercontainers. The guard time need only be long enough to prevent overlapping caused by transit time variations that cannot be equalised and to also enable a secure switch over between two supercontainers. The remainder of the time slot should, of course, be utilised as far as possible to utilise the transmission capacity as far as possible. Synchronisation measures are therefore only required to the extent of guaranteeing this guard time and, at the same time, read and evaluate these addresses securely. Such synchronisation measures can be implemented quite easily, even in the optical range, by means of switchable delay elements. 1- Current thinking is concentrating on designing a supercontainer so that the user data contain a so-called VC-4-container according to the SDH hierarchy. A plurality of alternative transmission paths are obtained preferentially by implementing a wave length multiplex on each transmission path. The multiplicity of the paths itself can also be used. In order that the invention may be carried into effcct an embodiment thereof will now be described in relation to the accompanying drawings in which: Figure I shows a telecommunications network with network-access exchange and transit exchange according to the invention. The telecommunications network according to Figure 1 comprises network-access exchanges SF11, ..., SF1N and STF1, ... STFN as well as transit exchanges SF21, ..., SF2N. The display according to Figure 1 only shows one transmission direction. Obviously, each exchange has corresponding functions in the other direction. In Figure 1, the complete telecommunications network is shown as a single exchange. This form of representation has also been taken from the description of an exchange. This description has been published as US patent 5,369,514. Specific reference is made to the contents of these papers. According to the present invention, the complete telecommunication network is regarded as a large 63 5 3 exchange, where the exchanges themselves are regarded as the individual exchange stages. The internal design of an exchange can, in principle, be the same. The complete network will not show the regular design of an exchange. 5 However, space-position converters S, which are implemented as optical switches, and frequency-position or wave-length converters F, which today can be implemented as optical elements, are provided. Time-position converters T are provided only in the very last exchange stage, prior to leaving the network. When entering and leaving the network, the data format in the connection range of 10 individual connection-specific data streams must be matched to those of the network and vice versa. This also requires intermediate storage, time-position • conversion and change of transmission speed. Initially, known measures as used in the current exchange technology have been provided for this. For further details please refer to the papers quoted in the above text. 15 t 8 </div>

Claims

<div class="application article clearfix printTableText" id="claims"> What we claim is:

1. A method of operating a telecommunication network having a plurality of network-access exchanges and a plurality of transit exchanges, with each network-access exchange connected directly or via an arbitrary number of transit exchanges to every other network-access exchange and to a plurality of network-access channels, wherein at each network-access exchange, user data coming from the network-access channels of this network-access exchange are combined into blocks such that each block only contains user data intended for network-access channels of a single destination network-access exchange, the user data within the respective block being assigned control data to assign the user data to a selected network-access channel at the destination, each block containing user data is assigned a block containing address data, and within each exchange, each user-data block is switched transparently in the direction of the destination network-access exchange based on the address data of the associated address-data block.

2. A method as claimed in claim 1, wherein the user data are ATM cells to which control data have been assigned in the respective cell headers.

3. A method as claimed in claim 1, wherein the user-data blocks and the respective address-data blocks assigned thereto succeed one another like in a data packet, with the address-data block used as a packet header.

4. A method as claimed in claim 1, wherein the user-data blocks and the address-data blocks assigned thereto are transmitted over separate, parallel transmission paths, and wherein the assignment follows from the relative temporal occurrence and the assignment of the transmission paths.

5. A method as claimed in claim 1, wherein synchronisation measures are taken to the extent that is required, on the one hand, to cause the blocks to succeed one another without overlapping and without appreciable waste of transmission capacity and, on the other, to read and evaluate the address data.

6. A method as claimed in claim 1, wherein for each transmission path, at least one alternative transmission path can be switched.

7. A network-access exchange, particularly a subscriber exchange, having a plurality of ports for network-access channels, particularly subscriber lines, and at least one port for a trunk to a transit exchange, wherein means are provided for combining user data coming from the network-access channels into blocks such that each block contains only user data intended for network-access channels of a single further network-access exchange, the user data in the respective block being assigned control data to assign them to a selected network-access channel at the destination, the means being further adapted to assign a block containing address data to each block containing user data, means being provided for transmitting user-data blocks and address-data blocks via a port tor a trunk to a transit exchange, and wherein means are provided for receiving user-data blocks and address-data blocks from a port for a trunk and for outputting the user data / 10 10 28 k contained in said blocks, based on the control data assigned thereto, via the port assigned to the selected network-access channel.

8. A transit exchange having a respective port for each trunk to another exchange, wherein means are provided for evaluating address-data blocks coming form a trunk and for switching said address-data blocks, together with user-data blocks assigned thereto, to another port for a trunk. ALCATEL AUSTRALIA LIMITED B. O'Connor Authorized Ag^nt P5/1 /I 703 NX Wfc 1 » APR 1996 RECCf/SD </div>