DE4313388C1 - Connecting network for communication system - has subscribers formed into connection groups dependent upon services which they use, groups exchanging information via central connecting unit - Google Patents

Abstract

The network has a subscriber station (TG1) and an interface (SS1) which receive information from a central peripheral interface unit (ACCN) in accordance with a synchronous transfer mode, with which the information in the transmission channels is introduced in fixed slots of a transmission frame. A second subscriber station (TG2) and a second interface (SS2) receive information from the central peripheral interface unit in accordance with the asynchronous transfer mode, whereby the information is composed into packets of constant length, which consist of head and information fields. A third subscriber station (TG3) and a third interface (SS3) receive information in the direction of the third subscriber station in accordance with a TDM process and in the direction of the third interface in accordance with an adaptive TDM process with multiple engagement. USE/ADVANTAGE - E.g. ATM ring network. Offers high flexibility and quality independently of services available.

Description

The invention relates to a connection network in a communication system.

Telecommunication systems of the future will increase compared to existing systems mend be constructed from fewer network levels, of which the main levels are essentially the access network and the transport network apply. The existing transmission technology Communication networks are "naturally grown" networks, which are adapted to the respective Services, traffic volume, etc., have been planned and implemented. So until the hay Most of the time, the mediated telephone service is responsible for planning and implementation of the networks determines. With the introduction of synchronous networks and the availability of The corresponding network elements are the services offered via the switched telephone service has been expanded to include narrowband services for voice and Data also broadband and data services for the rapid exchange of large data quantities (e.g. computer-computer communication), for the transmission of images etc., in a communication network are available.

Different services require corresponding transmission capacities or bit rates for the transmission of digital information in transmission channels according to the STM process ren (Synchronous Transfer Mode) or in the form of message packets or cells according to the ATM (Asynchronous Transfer Mode) process. Both methods are time-division multiplexed methods, of which the STM method for each bit rate class, for example 2 Mbit / s, 8 Mbit / s,. . ., 140 Mbit / s, separate information channels with a corresponding exchange device (switching matrix) is required, while the ATM procedure depends on each bitrate required number of cells filled with constant information Amount used. Therefore, in the latter method there is only one type of mediation direction (switching matrix) required, which conveys exactly the bit rate that the subscriber for just needed his desired service.

An extension of the range of services beyond the mediated telephone service is required Flexibility in connecting participants and in arranging different Bit rates. In addition, the quality achieved at today's level is that of the part to receive services used by subscribers. In particular, the delay times for Keep voice signals low to avoid repercussions on the network. This is in  With regard to a network structure based on the ATM transmission method from Be interpretation, because by packaging the information about the cells of a given length Delay times occur.

The connection of subscribers in the access network is increasingly via passive optical network (fiber to the home / curb), in which optical fibers are used the. Such a passive optical data network is in the British Telecom Technology Journal, Vol. 7. No. 2, April 1989, pages 100 to 113. Here are to implement the electrical signals in optical sizes, electro-optical converters, and for implementation the transmission procedures and formatting the information control devices seen. These are essentially present in a central connection unit, between the and the participants exchange information via optical branches / couplers (Splitter) in the passive transmission network.

Time division multiplexing (TDM) is used towards the subscriber and towards central access unit used an adaptive time division multiplexing (TDMA) whose In principle, transmission frames are constructed identically in both transmission directions. The different due to the different lengths of the optical fibers Runtimes of the information between the central connection unit and each time to summary of several subscriber subscriber line units provided by electronic delay devices in the subscriber line units compared. The calibration and setting of the electronic delay devices is operated by a control device in the central connection unit in cooperation with the individual subscriber line units performed. The passive optical transmission As is known, the supply network operates in accordance with the STM transmission method that the For the need for increased flexibility in service offering while maintaining the best service quality can be difficult.

The object of the invention is to provide a connection network of high flexibility and quality independently of the available range of services.

This object is achieved by the features specified in claim 1.

The flexibility in the access network is made available by providing different participants mer connection groups reached, of which a first subscriber connection group the pure STM transmission method for the transmission of STM-oriented services, such as. B. Speech and narrowband data, and a second subscriber line group the pure  ATM transmission method for the transmission of ATM-oriented services, such as. B. Broadband data, and a third subscriber line group the time division for the optional transmission of STM-oriented and ATM-oriented services via the use common passive optical transmission network. In this way, be agreed services, such as B. the telephone service, continue to transmit STM-oriented thereby the disadvantage of packet delays of a pure ATM transmission ver avoided driving and its advantages for new services, such as those with strong fluctuating bit rate requirements as with computer-computer communication to the contrary data exchange on the same transmission network. For Broadband and data services that require a higher bit rate (e.g. <8 Mb / s) are available pure ATM transmission method using the based on message packets supporting information in a known manner.

In such a connection network, the information between the parts subscriber line groups and the central line unit without format conversion depending on Application exchanged according to the different transmission methods, and thus ko cost-effective transmission paths and short delay times for the different Services are provided. It will be an optimal one in terms of flexibility and quality Transmission method for the respective service with the bit rate adapted to the service in the range of a few kbit / s to <100Mbit / s. By the Access networks according to the invention can use new services on the subscriber side the existing infrastructure and compliance with existing high quality requirements, in particular those to the voice signal switching, while avoiding the pure Disadvantages occurring in ATM or STM transmission methods are used.

It is advantageous to have several subscribers in a subscriber line group, each one To summarize subscriber line unit, which in the flow of information between the Participants and the central connection unit as participant-side control devices are switched.

It is advantageous that one for the respective subscriber line unit of the third Subscriber line group available transmission capacity to several the connected subscriber is divided. For example, with a calculation ner computer communication several data terminals with different or identi bitrate requirement for the transmission of message packets according to the time multi plex process can be switched on.  

It is also advantageous that for the selection of the addressable participants, each one Part of the transmission capacity of the subscriber line unit is allocated an individual duel subscriber identifier is provided, which as either address information Header field of the respective message packet or one of the respective subscriber connection unit defining address is added.

Advantageous for the further information flow running in two transmission directions it is in the central connection unit if it has a plurality of interface devices to connect the STM-oriented or ATM-oriented or mixed Has subscriber traffic. Coupling networks provide for the mediation of the transfer channels synchronously and information transmitted asynchronously in message packets for further concentration of participant traffic. Through a package rungs / Depaketierungseinrichtung the flow of information in one Rich device on an ATM basis and in the other transmission direction on an STM basis by each conversion of the information transmitted synchronously in transmission channels into asyn chronic message packets and vice versa. The through the package Renew / unpacket the information in the delay time range of less than 100 µs are tolerable.

It is advantageous if between the STM switching network and the packet rungs / Depaketierungseinrichtung a device for grouping in the STM coupling network concentrated on a predetermined granularity transmission channels to an over frame rate higher bit rate and to separate from the packaging / Depacketizer (S / A) coming information of the transmission frame is arranged. Such grouping is not required in an ATM switching network. rather, virtual connections are created for this.

A device is preferably provided for the further exchange of information on an ATM basis connected to the central connection unit to ver the incoming information share. This device has an annular or mesh structure with several Add / drop multiplexers or a cross-connect system. Training an ATM ring network with several connected central line units Bus lines for the individual services and from an add / drop multiplex device ensures a service-related distribution of the incoming information to the provider extension of the access network for the further flow of information after the asynchronous trans mode.

The invention is explained in more detail using exemplary embodiments. Show in detail

Fig. 1 shows the structure of a communication system with a terminal network and a transport network,

Fig. 2, the Pinzipschaltbild of the access network with subscriber line groups, the passive optical transmission network, the central unit and the terminal connection unit is turned on, the on device,

Fig. 3 is a block diagram of the central connecting unit,

Fig. 4 shows a pulse frame for the exchange of information over the passive optical Übertra supply network in the transmission direction from the central terminal unit to a part of the contractor terminal groups,

Fig. 5 and Fig. 6 block diagrams of the device connected to the connection unit Einrich device as an ATM ring network and as a cross-connect system for connecting the connection network, and

Fig. 7 is a schematic diagram of the access network as an ATM ring network with several central access units for the service-related distribution of the information.

In Fig. 1, a communication system is shown in principle. It has an ACC-NW connection network for connecting a large number of subscribers with a wide spectrum of services and a wide variety of service bit rates, and a transport network TRA-NW for providing network-wide connections and for switching replacement connections in the event of line interruptions. Electronic switching devices for service-related routing of signal paths serve as connecting elements between the ACC-NW connection network and the TRA-NW transport network. Through cross-connect systems CC and other distribution devices SW, the different bit rates can be switched according to the services desired by the participants.

The incoming information is distributed service-related, i.e. H. depend depending on the existence of an ATM (asynchronous transfer mode) - or STM (synchronous Transfer mode) -oriented service, a variable or constant service bit rate, a connection-oriented or connectionless service (e.g. data transmission through a local area network) etc., connections are made in the cross-connect system  Men CC or the other distribution facilities SW provided. In addition there is Leased lines in the form of leased lines (Least Lines) LL, which are directly between the ACC-NW connection network and the TRA-NW transport network.

The services used by the subscribers in the access network ACC-NW range from slow data transmission DATA (<10 kbit / s) via the telephone service BA ("Basic Access ", ISDN basic connection with 144 kbit / s), POTS (" Plain Old Telephone Service ") die fast data transmission DATA (e.g. 2 Mbit / s) up to broadband services (<100 Mbit / s), where the asynchronous transfer mode ATM is the basis for switching and Transfer of information forms. Digital broadband services, for example the broadband ISDN (Integrated Services Digital Network), the high-speed transmission through local area networks and future applications OTH such as B. Interactive data and motion picture communication. Other services are for example the voice exchange PA ("Primary Access"), leased lines in the form of Leased lines LL, subscriber connection systems for optical fibers (Fiber In The Loop) and subscriber connection systems for radio (Radio In The Loop).

Such a communication system has a computer-supported, not shown Network management for optimal use of the transport or connection network capacity as for the use of the services offered in the highest possible quality. An extension of the services offered in the ACC-NW network requires a high degree of flexibility for the Transmission of different bit rates while maintaining the quality of service and Availability, especially in malfunction and overload situations. That for the speech The asynchronous transfer is available for the optimally suitable synchronous transfer mode mode, in which the information is combined into message packets, and a number of message pairs determined depending on the required service bit rate keten be transmitted. This time-division multiplex method enables a high degree of flexibility in the Communication system related to future broadband applications and avoidance of predefined bit rate classes when using a purely STM-orien services. The conflicting requirements Delay times as short as possible for conventional voice transmission and after High flexibility for any expansion of the service offer can be only on an ATM-based or only on an STM-based communication system not without meet more.

The need for flexible handling of different bit rates while ensuring the quality of service of existing services is possible through the access network ACC-NW, whose structure is shown in principle in FIG. 2. Subscriber line groups TG1, TG2 and TG3 are connected to a central line unit ACCN by transmission devices in the form of optical fibers or metallic lines KL or in the form of a passive optical transmission network PON. The respective subscriber connection groups arise from the combination of subscribers as a function of the services they use and thus the required service bit rates for optimally utilizing a time-division multiplex method defined for the subscriber connection group.

A first subscriber line group TG1 comprises, for example, one subscriber locking system for radio RITL (Radio In The Loop) and the telephone service BA, POTS for speech signals. Several subscribers of the subscriber line group TG1, who use the same service with their end devices, for example telephone sets ten, who is connected to an associated subscriber connection unit DU (Distant Unit) the, as is the case for the subscribers of the subscriber line system RITL game is shown.

A second subscriber line group TG2 comprises subscribers with purely ATM-oriented services corresponding to higher service bit rates, for example fast data transmission lung DATA, a broadband network B-ISDN, and a local area network LAN for the Hochge speed transfer. The second subscriber line group TG2 points to the beginning of several data terminals for computer-computer communication and the end Devices of the broadband network B-ISDN associated subscriber line units NT (Network Termination) and TA (Terminal Adaption).

A third subscriber line group TG3 comprises subscribers, of which the remote sprechdienst BA and POTS, the voice mediation service PA, landline LL, and Data applications DATA (e.g. frame relay) can be used. Several participants in the different services are to an associated subscriber line unit DU1, DU2,. . ., TA can be connected, of which the subscriber connection unit DU1 (Distand Unit) for the subscribers of the telephone service BA and POTS, the subscriber connection unit DU2 (Distand Unit) for the participants of the voice mediation service PA or the Leased lines LL using subscribers, as well as the subscriber Connection unit TA (Terminal Adaption) provided for the respective data terminals are.  

The individual subscriber line groups are TG1, TG2 for the exchange of information and TG3 are coupled to transmission facilities, of which the transmission facilities conditions of the first subscriber line group TG1 as metallic lines KL, for example wise copper lines, the transmission facilities of the second subscriber connection group TG2 as fiber optic cable, as well as the transmission device of the third part subscriber line group TG3 are designed as a passive optical transmission network PON. The subscriber line groups TG1. . .TG3 to the central connection unit ACCN leading transmission facilities connect the individual subscribers Key groups with assigned interface devices SS1, SS2 and SS3 from zentra len connection unit ACCN.

The information is exchanged in both directions of transmission in time multiplex mode. Of course, separate transmission devices for both transmission directions are also possible. The information is transmitted on the metallic lines KL in accordance with the synchronous transfer mode, in which, as is known, these are inserted into time slots of a transmission frame which are permanently assigned to transmission channels and whose structure corresponds to that of a frame shown in FIG. 4. The optical waveguides LWL are used to transmit the information according to the asynchronous transfer mode, in which they are transmitted in message packets of constant length, consisting of a header field and an information field.

The exchange of information in both directions of transmission through passive optical Transmission network PON takes place towards the subscriber, i. H. to subscriber final group TG3, in time division multiplexing (TDM) and towards the central an terminal unit ACCN in the adaptive time division multiplex method (TDMA-Time Division Multiple Access) according to German published patent application DE A1 40 22 027. In contrast to known transmission network has the passive optical transmission network PON in the An final network ACC-NW about connection options for new services, such as data Transmission with 2 Mbit / s transmission capacity, in which the information is ATM-oriented to be transmitted asynchronously in message packets. The payload of the usually Transmission frame reserved for STM-oriented information can therefore be used with a ner number of message packets corresponding to that for the new service or services Available transmission capacity can be filled when connecting several Participants with their data terminals to the respectively assigned subscriber connection unit TA can be divided into these. The transmission capacity can be which are characterized by a burst-like exchange of information, by statistical Make good use of multiplexing the respective information.  

The services used by the subscribers of the third subscriber line group TG3 are connected to the passive optical transmission network PON by optical branching gene / coupler (splitter) OF1, OF2. . .OFn connected, from which to the participant-An closing units DU1, DU2. . .TA is branched in a star shape in the subscriber direction. The Coupling of the passive optical transmission network PON to the interface device SS3 of the central connection unit ACCN takes place through an optical fiber OF. To Measuring and setting of electronic delay devices in the participant mer connection units DU1. . .TA by the interface device SS3 in combination beit with the individual subscriber connection units to compensate for the by the un Different lengths of the fiber optic branches lead to overtime Transmission network PON are the individual subscriber line units certain time slots of the transmission frame reserved over which then in addition to the useful information Exchange-specific information can also be exchanged.

In the direction of transmission from the third subscriber line group TG3 to the central one Connection unit ACCN, for example, follow the information to be transmitted synchronously tion of the participants connected to the subscriber line unit DU1 speaking information to be transmitted synchronously to the subscriber lines Unit DU2 connected subscribers etc., up to the asynchronous in message packs ten to be transmitted information connected to the subscriber line unit TA its participant. The same applies to the opposite direction from the interface device SS3 to the assigned third subscriber line group TG3. It is by measuring and setting ensures that the entire transit time between sending an Si gnals from the central connection unit ACCN and the receipt of the respective response signals from one of the subscriber line units DU1. . .TA be a constant period of time carries, and thus their signals do not overlap.

To support the by separating into different subscriber line groups high flexibility achievable for the optimal use of appropriate time-division multiplexing methods if the existing quality of service is maintained, the central connection unit points ACCN in addition to the interface devices SS1, SS2 and SS3 for connecting the purely STM-oriented services, the purely ATM-oriented services and the optional STM or ATM-oriented services, an STM switching network SNS and an ATM switching network SNA on. Of course, known measures to secure the over channels of transmission, for example through redundant design of the switching networks, are seized the. The STM switching network SNS and the ATM switching network SNA are both with the  Interface device SS3 and individually alone with the interface device SS1 or connected to the interface device SS2.

The synchronous flow of information is concentrated in the STM switching network SNS, for example, based on a granularity of 64 kbit / s according to a transmission ka nal for an ISDN basic access ("Basic Access"), and in the direction of the transport network then one based on a higher transmission capacity, for example 2 Mbit / s existing grouping, in which unused transmission channels are disregarded. The Grouping of active transmission channels to form a higher transmission frame Transmission capacity, for example a 2 Mbit / s transmission frame, causes In addition, flexible handling of the services requested by the participants.

A packaging / depacketing device S / A is connected to the STM coupling network SNS Generation of message packets from those combined into the transmission frame Information, for example switched on with a transmission capacity of 2 Mbit / s. The resulting delay times due to the packaging of the information are in the range of less than 100 µs, and are tolerable for the central access unit ACCN. In the opposite direction to the subscriber line groups TG1. . . performs the packaging / Depacketizer S / A a separation of those arriving in the common frame Information in order to be able to transmit SNS on the basis of 64 kbit / s in the switching network nen. In the ATM switching network SNA, virtual connections are established in a known manner based on path and channel identifiers, the bit rates of which vary according to the services desired by the participants can be defined in each case. A grouping like with the STM coupling network SNS is not required.

To support flexibility in the exchange of information, the central access unit ACCN has a further interface device SS2 'which is connected to the ATM switching network SNA and the packetizing / depacketing device S / A. Optionally, a further interface device SS1 'coupled to both switching networks SNS and SNA' can be provided for the forwarding of the information in accordance with the synchronous transfer mode. The further interface device SS2 'is used to connect the central connection unit ACCN for the forwarding of the information according to the asynchronous transfer mode and is to an ATM interface AS, the structures of which FIG. 5 and FIG. 6 show, as a transition from Access network ACC-NW to the electronic switching devices CC, SW and the rental lines LL is connected.

FIG. 3 shows a more detailed schematic diagram of the central connection unit ACCN . A switching device SU for directing the STM-oriented information flow to the STM switching network SNS and for directing the ATM-oriented information flow to the ATM switching network SNA is connected to the interface device SS3. The routing takes place as a function of control information that can be taken from a control memory CM. In the simplest case, the switching device SU consists of a fault-controlled changeover switch, which assumes a first position when STM-oriented information is present and a second position for switching through in both transmission directions when ATM-oriented information is present.

In the event that the switching device SU is a connection between the interfaces direction SS3 and the STM switching network SNS, can use the information one ISDN basic access (BA Basic Access) the information belonging to the participants NEN, for example voice signals, are fed into the STM switching network SNS. The Formation of the higher bit rate transmission frame in one transmission direction Summary of speech signals belonging only to the participants or the The signals for the switching network SNS are processed in the opposite direction by a between the STM switching network SNS and the packaging / depacketing device S / A arranged frame generator FG. For registering and reading out the in both Information to be exchanged for transmission directions are sequence controllers CM-TD and CM-2M connected to the STM switching network SNS.

In the event that the switching device SU is a connection between the interfaces direction SS3 and the ATM switching network SNA establishes virtual connections for built up both directions of transmission. There are in the ATM transmission path manages a plurality of sequential control units QC connected to the control memory CM tete facilities, of which a facility CS to synchronize the information flow to the limits of the respective message packets, a device EC for insertion of empty message packets in the continuous packet stream, and a facility CQ serve to temporarily store parts of a message package. Between the Buffer device CQ and the ATM switching network SNA is a device RH (Routing Header) with information about the connection path through the switching network orderly. This information can be used in the transmission direction to the switching network message packet added and in the direction of transmission to the subscriber from respective message package can be removed. All functions of the central To closing unit ACCN are managed by a central controller, not shown  and monitored during configuration and maintenance procedures via a not shown Interface to external facilities are triggered.

In FIG. 4, the transmission frame PR for the transmission direction from the central terminal unit to the subscriber terminals of the third subscriber line groups is shown. The transmission frame in the opposite direction is basically the same. The frame duration is 2 ms, which corresponds to a frame repetition frequency of 500 Hz. In addition to a frame information part (frame overhead) FROH, a total of 16 basic blocks BS1. . .S16 with 4096 bits each. Each of these individual base blocks BSj in the same way into sub-blocks SB1. . .SB512 is divided with 8 bits each. This results in a transmission capacity of 64 kbit / s for a base channel.

A number n of such basic channels B-1. . .B-n with the useful information are at for example to the first subscriber line unit DU1 or to the subscriber line unit TA of the third subscriber line group. S1 and H1 denote mediators information, while OH1 for transferring information to organizational serves purposes. Consequently, there is a total transmission capacity of n × 64 kbit / s available to the respective participants. Two of these base channels each contain 64 kbit / s the user information of an ISDN basic access (BA Basic Access). At the Exchange of information between the first subscriber line unit DU1 and the zen central connection unit contain the basic channels B-1. . .B-n in the transmission channels CH1, CH2 ,. . .CHn, each occupying a time slot of the transmission frame PR, according to the Synchronous transfer mode STM information to be transferred. The establishment of the Number n is dependent on the number of subscriber line units DU1 connected subscribers and the services they want.

When there is an exchange of information between the subscriber line unit TA and the The central connection unit also becomes the basic channels B-1. . .B-n transmitted, however in contrast to the case of synchronous transmission shown above, that in Nach straightening packages CE1, CE2 ,. . .CEm contain information to be transmitted asynchronously. There at the number n depends on the bit rate that is sent to the subscriber line unit TA connected participants have been assigned. When dividing the transmission available for the subscriber line unit TA as a whole capacity of, for example, 2 Mbit / s to several of the connected participants whose data terminals through a to the address AD of the subscriber line TA included in the field OH1, added address information I can be selected. Dude natively, the individual subscribers consisting of the address information I can  each message packet consisting of HD header field and NI information field be added.

To connect the access network ACC-NW Fig. 5 and Fig. 6 show under schiedliche configurations of the ATM interface AS. In Fig. 5 are add / drop multiple xer ADM presented with integrated line interface high bit rate, which are connected to an ATM network AADR ring. The ATM ring network AADR has a ring manager, not shown, for managing and monitoring it. The ring network behaves like a distributed cross-connect multiplex system, which can react quickly and reliably to changes by connecting multiplex, distributor and line functions in the add / drop multiplexers in the ring. In addition, the presence of an ATM ring network AADR in the access network has the advantage that it enables simple but effective equivalent switching measures in the event of a fault.

Compared to the ring structure according to FIG. 5, the ATM interface AS in FIG. 6 has a mesh structure with an ATM cross-connect system including the multiplex functions. The use of a cross-connect system based on the asynchronous transfer mode in a meshed network combines the advantage of a high degree of flexibility in handling a wide variety of service bit rates in the access network with the advantage of high operational reliability and network-wide alternative routing. The structures according to the Fig. 5 and Fig. 6 lead to the exchange of information is based on the interface to access network distributed to those used by the subscribers services.

Another structure of the access network ACC-NW is shown as a schematic diagram in Fig. 7. The access network ACC-NW is characterized by repeated arrangement of access units ACCN1, ACCN2, ACCN3. . ., each having the structure of FIG. 2, in an ATM ring network ADDR. To each of the ACCN1. . . are services SV1, SV2 used by the subscribers. . .SVk switched on, for which on the respective service, e.g. B. SV1, associated line of the ring network AADR the virtual connections in the individual line units ACCN1. . . summarize. As an ATM interface for connecting the access network ACC-NW, an add / drop multiplexer ADM is provided, which, as a cross-connect multiplexer, distributes the information exchanged on the busbars according to service-related criteria, ie routing the signal paths separately according to the service SV1, the service SV2. . ., the SVk service.

Overall, the structures of the Access network in a communication system one known, either for the STM technology or the ATM technology oriented structures a gain in flexi bility when connecting subscribers and transmitting a wide range of service bit rates when using the existing infrastructure of existing networks, an independence of the Access network, if applicable, future services from the respective network construction, maintaining the quality of service at today's level, as well as high availability Availability of the devices used in the connection network, for example by redundant ones Design and use of appropriate network topologies (e.g. ATM ring networks).

Claims (11)

1. Access network in a communication system with participants, which are combined depending on the services used by the participants (POTS, BA, PA, DATA, ...) to subscriber connection groups (TG1, TG2, TG3), which have a central Connection unit (ACCN) exchange information, with between

• - A first subscriber line group (TG1) and an assigned interface device (SS1) of the central line unit (ACCN) the information is transmitted after the synchronous transfer mode, in which the information in transmission channels permanently assigned time slots of a transmission frame, who who inserted the
• - A second subscriber line group (TG2) and an associated interface device (SS2) of the central line unit (ACCN), the information is transmitted according to the asynchronous transfer mode, in which the information is merged into message packets of constant length, each field from a header and an information field exist
• - A third subscriber line group (TG3) and an assigned interface device (SS3) of the central line unit (ACCN) the information towards the subscriber line group (TG3) according to a time-division multiplexing method and towards the interface device (SS3) according to an adaptive time-division multiplexing method are transmitted with multiple access, in each of which the time slots of a transmission frame (PR) are filled either with the information to be transmitted asynchronously in message packets (CE1, CE2 ,...) or synchronously in transmission channels (CH1, CH2 ,...), and between
• - The subscriber line groups (TG1, TG2, TG3) and the respective interface devices (SS1, SS2, SS3) one or more transmission devices (KL, LWL, PON) are provided, of which the transmission device (PON) for the exchange of the the time-division multiplexing method or the adaptive time-division multiplexing method is formed as a passive optical transmission network, to which the subscribers combined to form the third subscriber line group (TG3) are connected.

2. Access network according to claim 1, characterized, that to combine several subscribers of a subscriber line group (e.g. TG3) subscriber line units (z. B. DU1, DU2, TA) are formed with the or the transmission devices (e.g. PON) are coupled.   3. Connection network according to claim 2, characterized, that one for the respective subscriber line unit (e.g. TA) of the third subscriber line final group (TG3) available transmission capacity on several of the specified closed participants is divided. 4. Connection network according to claim 3, characterized, that the individual subscribers can be addressed by an individual subscriber identifier. 5. access network according to claim 4, characterized, that the individual subscriber identifier as an address information (I) to the header field (HD) of the respective message package (e.g. CE1) is added. 6. access network according to claim 4, characterized, that the individual subscriber identifier as an address information (I) to the one current subscriber connection unit (e.g. TA) defining address (AD) is added. 7. Connection network according to one of the preceding claims, characterized in that in the central connection unit

• - A first switching network (SNS) for concentrating the information transmitted synchronously in the transmission channels with the first interface device (SS1) and a second switching network (SNA) for concentrating the information transmitted asynchronously in the message packets with the second interface device (SS2) and both switching networks (SNS and SNA) are connected to the third interface device (SS3), and
• - A packetizing / depacketing device (S / A) is provided for converting the information provided in the transmission channels into message packets and vice versa, and the packetizing / depacketizing device (S / A) and the second switching network (SNA) with a further interface device (SS2 ′ ) are connected to forward the information arriving after the asynchronous transfer mode.

8. access network according to claim 7,  characterized, that in the central line unit (ACCN) between the first switching network (SNS) and the packaging / depacketing device (S / A) is arranged a device (FG), of the In provided in one direction of transmission by the switching network (SNS) Formations combined into a transmission frame or in the other transmission direction of coming from the packaging / depacketing facility (S / A) Formations of the transmission framework are separated. 9. Connection network according to one of claims 1 to 8, characterized, that to the central connection unit (ACCN) a device (AS) for further information mation exchange switched on after the asynchronous transfer mode and as a ring network (AADR) is formed, to which several add / drop multiplexing devices (ADM) for Distributing the incoming information are connected. 10. Connection network according to one of claims 1 to 8, characterized, that to the central connection unit (ACCN) a device (AS) for further information mation exchange switched on after the asynchronous transfer mode and as meshed Cross-Connect-System (ACCS) trained to distribute the incoming information det. 11. Connection network according to one of claims 1 to 8, marked by a repeated use of the central connection unit (ACC1, ACC2, ACC3, ...) as Parts of a ring network (ADR) for the exchange of information after asynchronous Transfer mode, in which each of the services used by the participants (SV1, SV2,..., SVk) an associated manifold is available, and by an the ring network (ADR) connected add / drop multiplex device (ADM) to distribute the incoming information according to the individual services (SV1, SV2, ...).