WO1999014959A1

WO1999014959A1 - Patterned distribution of node addressed traffic to plural connected sub-nodes

Info

Publication number: WO1999014959A1
Application number: PCT/SE1998/001594
Authority: WO
Inventors: Yves Lemieux
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 1997-09-18
Filing date: 1998-09-08
Publication date: 1999-03-25
Also published as: AU9192798A

Abstract

A message (454) intended for delivery to a sub-node (448) is formatted, in accordance with an agreed upon distribution pattern for a plurality of sub-nodes (448) connected to an end node (444), into a communication (470) addressed to the end node (444) associated with the destination sub-node (448). The distribution pattern specifies a sequenced order (472) of the plurality of sub-nodes (448) relating to a message distribution pattern. When the communication (470) is received by the addressee end node (444), the message or messages (454) contained therein and delimited by markers are distributed to the attached sub-nodes (448) following the sequenced order (472) of the agreed distribution pattern. Accordingly, the need for direct sub-node (448) addressing of message communications (470) is obviated.

Description

PATTERNED DISTRIBUTION OF NODE ADDRESSED TRAFFIC TO PLURAL CONNECTED SUB-NODES

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application for Patent is related to previously filed, commonly assigned, co-pending Application for Patent Serial Number 08/757,581, entitled "SYSTEM AND METHOD FOR THE COMMUNICATION OF OPERATION AND MAINTENANCE, ADMINISTEATION AND PROVISIONING INFORMATION

OVER AN ASYNCHRONOUS TRANSFER MODE NETWORK" filed November 27, 1996, which is a continuation-in-part of previously filed, commonly assigned, co- pending Application for Patent Serial Number 08/615,096, entitled "SYSTEM SUPPORTING VARIABLE BANDWIDTH ASYNCHRONOUS TRANSFER MODE NETWORK ACCESS FOR WIRELINE AND WIRELESS

COMMUNICATIONS" filed October 28, 1996. The disclosures of each of the foregoing applications for patent are incorporated by reference herein.

BACKGROUND OF THE INVENTION Technical Field of the Invention The present invention relates to communications networks including addressable end nodes where a plurality of sub-nodes are connected to each end node and, in particular, to a method and apparatus for delimiting and distributing end node addressed traffic to the connected plurality of sub-nodes. Description of Related Art Reference is now made to FIGURE 1 wherein there is shown a block diagram of a prior art communications network 410 comprising a source end node 412 and a destination end node 414 connected to each other through a transport network 416 (such as a packet switched network of, for example, the frame relay or asynchronous transfer mode variety). It should not be implied from the use of the terms "source" and "destination" that end node 412 only originates communications and that end node

414 only receives communications. On the contrary, the use of these terms is restricted to the context of a particular communication, as the end node 414 may also originate communications in certain situations as well. Although not specifically shown, the network 410 further likely includes a plurality of each type of end node 412 and 414. A plurality of destination sub-nodes 418 are included in the network 410 connected to the destination end node 414 via communications links 420. In this prior art network configuration, both the destination end node 414 and each of the plurality of destination sub-nodes 418 are addressable. By this it is meant that all nodes of the network have network addresses and the source end node 412 may generate a communication for transmission over the transport network 416 addressed for the destination end node or addressed for a particular one of the destination sub-nodes connected thereto. Pursuant to well known routing table processing, the addressed communication is directed through the transport network 416 to the destination end node 414 and then routed by the destination end node over the communications links 420 to the proper addressee destination sub-node 418.

FIGURE 2 illustrates an exemplary format 422 used in the prior art network of FIGURE 1 for such a packet data communication. The format 422 comprises a data field 424 containing the information to be communicated and an address field 426 containing the network address for the destination node (either end node 414 or one of the sub-nodes 418) to which the communication is to be delivered. With respect to both the destination end node 414 and the destination sub-nodes 418, each node has a unique network address. In the case of the destination sub-node 418, this address typically comprises a primary address relating to the destination end node 414 to which they are connected along with a sub-address that particularly identifies the destination sub-node.

Referring now in combination to both FIGURE 1 and FIGURE 2, a number of drawbacks have been noted with respect to the prior art network configuration and addressing scheme. One noted drawback is that each destination end node 414 must be able to implement routing table processing in order to process the address field 426 of the communication and accurately route received the communications to the appropriate destination sub-nodes 418. Such routing table processing at the destination end node 414 may, however, become very complex as the number of destination sub-nodes 418 increases dramatically (for example, when thousands of sub-nodes are provided). Another noted drawback is that large address fields 426 which support the inclusion of sub-node related addressing data serve to add to the data overhead for message communication. This reduces the amount of network 410 supplied bandwidth (i.e., capacity) available to carry the information to be communicated (i.e., the payload). If the address field is conversely limited or restricted in size so as to reduce the adverse affects on payload capacity, the smaller sized addressing field unduly restricts the number of uniquely addressable nodes in the network and, in particular, restricts the number of destination sub-nodes 418 which may be connected to a single destination end node 414 and uniquely addressed.

SUMMARY OF THE INVENTION A message intended for delivery to a sub-node is formatted, in accordance with an agreed upon distribution pattern for a plurality of sub-nodes connected to an end node, into a communication addressed to the end node associated with the destination sub-node. The distribution pattern specifies a sequenced order of the plurality of sub- nodes relating to a message distribution pattern. When the communication is received by the addressee end node, the message or messages contained therein are distributed to the attached sub-nodes following the sequenced order of the agreed upon distribution pattern.

In one embodiment of the present invention, a communication including a message for a single one of the sub-nodes is formatted and then transmitted in accordance with the sequenced order of the agreed upon distribution pattern. Each communication is addressed to the destination end node to which the intended recipient sub-node is connected. Upon destination end node receipt of each communication, the included message is extracted and distributed to a next one of the sub-nodes identified in the sequenced order. In another embodiment, a communication is formatted in accordance with the sequenced order of the agreed upon distribution pattern to include plural messages for a corresponding plurality of sub-nodes. The communication is addressed and sent to the destination end node to which the plural intended recipient sub-nodes are connected. Upon destination end node receipt of the communication, the included messages are extracted and distributed to the sub-nodes following the sequenced order. The distribution pattern scheme for communicating messages to sub-nodes is especially useful in those communications networks which include a substantial number of sub-nodes connected to each destination end node. For example, in a cellular telephone network wherein base station controllers comprise the destination end nodes and base stations comprise the sub-nodes, separate addressing schemes for the individual base stations may not be efficient. This is especially the case where the cellular telephone network is designed to include not only umbrella or macro-cells, but also micro-cells and pico-cells, and each cell is serviced by a separate base station. The use of the sequenced order of an agreed upon distribution pattern to drive base station controller distribution of base station messages accordingly obviates the need for separate sub-node network addressing with respect to thousands of individual base stations and provides for improved and more efficient network communications performance.

BRIEF DESCRIPTION OF THE DRAWINGS A more complete understanding of the method and apparatus of the present invention may be acquired by reference to the following Detailed Description when taken in conjunction with the accompanying Drawings wherein:

FIGURE 1, previously described, is a block diagram of a prior art communications network comprising a source end node and a destination end node connected to each other through a transport network;

FIGURE 2, previously described, is a diagram illustrating an exemplary format for a packet data communication transmitted over the prior art communications network of FIGURE 1;

FIGURE 3 is a block diagram of a communications network in accordance with the present invention comprising a source end node and a destination end node connected to each other through a transport network;

FIGURE 4 is a diagram illustrating a first format for a packet data communications transmitted over the communications network of FIGURE 3;

FIGURE 5 is a message flow diagram illustrating patterned distribution of messages communicated using the format of FIGURE 4; FIGURE 6 is a diagram illustrating another format for a packet data communications transmitted over the communications network of FIGURE 3;

FIGURE 7 is a message flow diagram illustrating patterned distribution of messages communicated using the format of FIGURE 6; FIGURE 8 is a block diagram of a communications system utilizing an asynchronous transfer mode (ATM) transport network; and

FIGURE 9 illustrates the configuration of an ATM cell;

FIGURE 10 illustrates a multi-level data bit stream basic block;

FIGURE 11 is a communications line diagram illustrating by way of example the connections and associated transmission bit rates for a given communication handled by the communications system of FIGURE 8; and

FIGURE 12 is a block diagram of a portion of a cellular telecommunications system utilizing the network configuration of FIGURE 3 and the communications system of FIGURE 8.

DETAILED DESCRIPTION OF THE DRAWINGS

Reference is now made to FIGURE 3 wherein there is shown a block diagram of a communications network 440 in accordance with the present invention comprising a source end node 442 and a destination end node 444 connected to each other through a transport network 446 (such as a packet switched network of, for example, the frame relay or asynchronous transfer mode variety). It should not be implied from the use of the terms "source" and "destmation" that end node 442 only originates communications and that end node 444 only receives communications. On the contrary, the use of these terms is restricted to the context of a particular transmitted communication, as the end node 444 may also originate communications as well. Although not specifically shown, the network 440 further likely includes a plurality of each type of end node 442 and 444. A plurality of destination sub-nodes 448 are included in the network 440 connected to the destination end node 444 via communications links 450. In this network configuration, the destination end node 444 is addressable while each of the plurality of destmation sub-nodes 448 are not network addressable, but may be locally addressable for address re-use. By this it is meant that the source end node 442 may generate a communication for transmission over the transport network 446 addressed only for the destination end node 444. No communication may be literally network "addressed" for a particular one of the destination sub-nodes 448, although a technique (discussed herein) is provided by the present invention for distributing destination end node 444 addressed communications to the proper sub-nodes.

Pursuant to well known routing table processing, the addressed communication is first directed through the transport network 446 to the addressee destination end node 444. At that point, a message contained within the communication is distributed by the destination end node 444 over the communications links 450 to the proper destination sub-node 448 in accordance with an agreed upon distribution pattern for the plurality of sub-nodes connected to that addressee end node 444. This distribution pattern specifies a sequenced order of the plurality of sub-nodes 448 for the distribution of a single message or plural messages contained within each received communication. Accordingly, distribution of the message(s) in a received communication is made to the sub-nodes 448 following the sequenced order of the agreed distribution pattern.

FIGURE 4 illustrates one format 452 used in the network of FIGURE 3 for such a packet data communication. The format 452 comprises a data field 454 containing the information (i.e., a single message) to be communicated and an address field 456 containing the (primary) address for the destination end node 444 for the sub- node 448 to which the included message is to be delivered. In this case, only the destination end node 444 has a unique network address. Messages for a particular destination sub-node 448, are not literally network "addressed" for that sub-node, but are rather transmitted to the associated destination end node 444 only when that particular destination sub-node comes up in the sequenced order specified by the agreed upon distribution pattern for that destination end node.

Reference is now made in combination to both FIGURE 3 and FIGURE 4. A more complete understanding of one embodiment of the present invention may be obtained by reference to a specific example. Suppose there are n destination sub- nodes 448(1 )-448(n) connected to the destination end node 444. Further suppose that the agreed upon distribution pattern comprises an ascending and repeating numerical sequenced order (i.e., l,2,3,...,n-l,n,l,2,...). If a number of messages need to be sent from the source end node 442 to the plurality of sub-nodes 448, these sub-node messages are continually arranged sequentially in accordance with the distribution pattern for the sub-nodes. A communication containing a message for the first sub- node 448(1) is then formatted in accordance with the pattern, addressed for the destination end node 444 and transmitted over the transport network 446. A communication containing a message for the second sub-node 448(2) is then formatted and transmitted after the first communication. That communication is then followed by a communication formatted containing a message for the third sub-node 448(3), and so on, up to the transmission of a communication formatted containing a message for the last sub-node 448(n). The formatting and transmission process is repeated, starting again with a communication formatted containing a message for the first sub- node 448(1), and proceeds in accordance with the sequenced order of the distribution pattern up to another transmission formatted containing a message for the last sub- node 448(n). Further repetition occurs as long as a need for the transmission of sub- node message related communications continues.

At the destination end node 444, the transmitted communications addressed for the destination end node are sequentially received. This embodiment of the invention further assumes that the transport network 446 functions to maintain the sent ordering of the communications. The destination end node 444 then distributes the messages of the sequentially received communications, one by one, to the plurality of sub-nodes

448 in accordance with the same distribution pattern used by the source end node 442 (i.e., an ascending and repeating numerical sequenced order). Thus, the message of a first received communication addressed for the destination end node 444 is distributed to the first sub-node 448(1). The message of a next received communication is then distributed to the second sub-node 448(2), and so on, up to receipt of an n-th communication whose message is distributed to the last sub-node 448(n). The distribution process then repeats, distributing the message of a next received communication again to the first sub-node 448(1), and continues with the sequenced order of the distribution pattern up to another transmission whose message is distributed to the last sub-node 448(n). Further repetition occurs as long as sub- node message related communications addressed to the destination end node 444 continue to be received. It will, of course, be recognized that any sequenced order of the agreed distribution pattern may be used. For example, an ascending and repeating, odd/even numerical sequenced order may be used (i.e., 1,3,5,...,n-l,2,4,...,n,l,3,...). Alternatively, descending and repeating sequences may be used. Furthermore, not every one of the n sub-nodes 448 need necessarily be included in the sequenced order of the agreed distribution pattern. For example, when not all of the sub-nodes 448 are in current use, they are not included in the sequence. In this regard, it is recognized that the sequenced order of the agreed distribution pattern further may be dynamically altered to account for changes in network use as well as network configuration. The patterned distribution of messages communicated by the network of

FIGURE 3 using the format of FIGURE 4 is illustrated in the message flow diagram of FIGURE 5. At the source end node 442, a plurality of communications 470 are assembled. Each of the communications is in the format 452 of FIGURE 4 including an address field 456 and a data field 454. The address field of each communication 470 includes data (i.e., a network address) identifying the particular destination end node (Al) 444 for the communication. The data field 454 includes a message for a particular one of the sub-nodes 448. The communications are then sequentially transmitted over the transport network 446 in accordance with an agreed upon distribution pattern. Thus, the cornmunication 470 containing a message for a first sub-node 448 in the sequenced order 472 of the agreed distribution pattern is sent, followed by the communication containing a message for a second sub-node in the sequenced order, and so on, up to the communication containing a message for a last sub-node 448 in the sequenced order. Sending of the communications with sub-node messages then repeats again following the sequenced order 472 of the agreed distribution pattern. As each communication 470 is sequentially received by the addressee (Al) destination end node 444, the message contained in the data field 454 is extracted and distributed 474 to the proper sub-node 448 in accordance with the same agreed upon distribution pattern. Thus, the message in a first received communication 470 is distributed 474 to a first sub-node 448 in the sequenced order 472 of the agreed distribution pattern, followed by the distribution to a second sub- node in the sequenced order of the message in a next received communication, and so on, up to the message distribution to a last sub-node 448 in the sequenced order. The distribution 474 of sub-node messages from received communications 470 then repeats each time following the sequenced order 472 of the agreed distribution pattern. Reference is now made to FIGURE 6 wherein there is shown an illustration of another format 452' used in the network of FIGURE 3 for packet data communications. The format 452' comprises a data field 454' containing plural sub- node related information to be communicated and an address field 456' containing the (primary) address for the destination end node 444 for the plural sub-nodes 448 to which the information is to be delivered. Again, only the destination end node 444 has a unique network address. Messages for a particular destination sub-node 448, are not literally "addressed" for that sub-node, but are rather transmitted to the associated destination end node 444 along with other messages for the other sub-nodes also connected to the addressee destination end node. The data field 454' accordingly is partitioned into a plurality of sub-data fields 458' wherein each sub-data field contains a message for a certain one of the plurality of destination sub-nodes 448. The messages are inserted into particular ones of the sub-data fields 458' in accordance with a sequenced order specified by an agreed upon distribution pattern for that destmation end node 444.

Reference is now made in combination to both FIGURE 3 and FIGURE 5. A more complete understanding of another embodiment of the present invention may be obtained by reference to a specific example. Suppose there are n destination sub- nodes 448(l)-448(n) connected to the destination end node 444. Further suppose that the agreed upon distribution pattern comprises an ascending and repeating numerical sequenced order (i.e., 1,2,3,...,n-l,n,l,2,...). If a number of messages need to be sent from the source end node 442 to the plurality of sub-nodes 448, these messages are continually inserted into the sub-data fields 458' of the format 452' in accordance with the distribution pattern for the sub-nodes. Thus, a message for the first sub-node 448(1) is inserted into a first sub-data field 458(1)', a message for the second sub-node 448(2) is inserted into the second sub-data field 458(2)', and so on, up until a message for the last sub-node 448(n) is inserted into the last sub-data field 458(n)'. The formatted communication, including all of the messages inserted for the sub-nodes

448, is then addressed for the associated destination end node 444 and transmitted over the transport network 446. As more messages for the sub-nodes need to be transmitted, additional communications are formatted in the same manner and transmitted. Repetition of the process for inserting messages into the proper sub-data field 458' specified by the sequenced order of the distribution pattern and then transmitting the communication over the transport network 446 continues as long as 5 messages need to be sent from the source end node 442 to the destination sub-nodes

448.

At the destination end node 444, each of the transmitted communications addressed for the destination end node is received. This embodiment of the invention does not necessarily require that the transport network 446 function maintain the 0 ordering of the sent communications. The destination end node 444 then extracts the messages from the sub-data fields 458' of the data field 454', and distributes the extracted messages, one by one, to the plurality of sub-nodes 448 in accordance with the same distribution pattern used by the source end node 442 (i.e., an ascending and repeating numerical sequenced order). Thus, the message from the first sub-data field 5 458(1)' in a communication addressed for the destination end node 444 is distributed to the first sub-node 448(1). The message from the second sub-data field 458(2)' is then distributed to the second sub-node 448(2), and so on, up to distributing the message from the last sub-data field 458(n)' to the last sub-node 448(n). The distribution process then repeats, distributing messages from a next received 0 communication to the sub-nodes 448 again in accordance with the sequenced order of the distribution pattern. Further repetition occurs as long as communications including plural sub-node messages addressed to the destination end node 444 continued to be received.

Again, it is recognized that any sequenced order of the agreed distribution 5 pattern may be used. For example, an ascending and repeating, odd/even numerical sequenced order may be used (i.e., 1,3,5,...,n-l,2,4,...,n,l,3,...). Alternatively, descending and repeating sequences may be used. Furthermore, not every one of the n sub-nodes 448 need necessarily be included in the sequenced order of the agreed distribution pattern. For example, it could be noted that not all sub-nodes 448 are in o current use, and accordingly they would not be included in the sequence. In this regard, it is recognized that the sequenced order of the agreed distribution pattern may be dynamically altered to account for changes in network use as well as network configuration.

The patterned distribution of messages communicated by the network of FIGURE 3 using the format of FIGURE 6 is illustrated in the message flow diagram of FIGURE 7. At the source end node 442, a communication 470 is assembled. The communication is in the format 452' of FIGURE 6 including an address field 456' and a data field 454'. The address field 456' of the communication 470 includes data (i.e., a network address) identifying the particular destination end node (Al) 444 for the communication. The data field 454' includes a plurality of sub-data fields 458', wherein each sub-data field includes a message for a particular one of the sub-nodes

448, and the sub-data fields are organized in accordance with an agreed upon distribution pattern. Thus, the data field 454' contains, in the sub-data fields 458', a message for a first sub-node 448 in the sequenced order 472 of the agreed distribution pattern, followed by a message for a second sub-node in the sequenced order, and so on, up to a message for a last sub-node 448 in the sequenced order. The communication 470 is then transmitted over the transport network 446. Additional communications 470, each including plural sub-node messages organized following the sequenced order 472 of the agreed distribution pattern, are subsequently sent. As each communication 470 is received by the addressee (Al) destination end node 444, the messages contained in the data field 454' are extracted and distributed 474 to the proper sub-node 448 in accordance with the same agreed upon distribution pattern. Thus, the message in a first sub-data field 458' in the received communication 470 is distributed 474 to a first sub-node 448 in the sequenced order 472 of the agreed distribution pattern, followed by the distribution of the message in the second sub-data field to a second sub-node in the sequenced order of the message in a next received communication, and so on, up to the distribution of the message in the last sub-data field to a last sub-node 448 in the sequenced order. The distribution 474 of the plural sub-node messages in each received communication 470 then repeats, each time following the sequenced order 472 of the agreed distribution pattern. No matter what the sequenced order of the agreed distribution pattern, it is imperative that the pattern be agreed upon by the source end node 442 and the destination end node 444. Without such agreement, an accurate distribution of the communications in the absence of sub-node addressing is impossible. In accordance with one embodiment of the present invention, the source end node 442 and the destination end node 444 exchange communications over the transport network 446 specifying which sequenced order of the agreed distribution pattern is to be used. In another embodiment of the present invention, as illustrated in FIGURE 3, the network

440 further includes a transport network management system (TNMS) 460 that selects the sequenced order of the agreed distribution pattern to be used, and communicates that information to the source end node 442 and the destination end node 444 for implementation. Either embodiment supports dynamic control over the selection of the sub-nodes 448 that are included within the sequenced order of the agreed distribution pattern, as well as selection of the sequenced order itself.

It is further understood that the network 440 may include plural destination end nodes 444 each receiving sub-node communications from at least one source end node 442. In such a case, the use of the transport network management system 460 to choose the sequenced order of the agreed distribution pattern further permits the selection of a different sequenced order of the agreed distribution pattern for use by each one of the destination end nodes 444 and for use by the source end node 442 in formatting communications transmitted to those destination end nodes. Distribution of loading on the source end node 442 as well as on the transport network 446 may then be efficiently controlled. Accordingly, the transport network management system

460 functions to monitor operation of the end nodes 442 and 444, as well as the transport network 446, evaluate the monitored operation, and select the appropriate sequenced order of the agreed distribution pattern for use by each one of the destination end nodes 444 to maximize the efficiency of network operation. In one embodiment of the invention, the transport network management system

460 is connected via commumcations links 462 to each of the source and destination end nodes 442 and 444, respectively. In this configuration, the transport network management system 460 has direct communications access to each of the end nodes 442 and 444. In another embodiment of the invention, the transport network management system 460 is connected via a communications link 464 to only one of the end nodes 442 or 444. For example, as shown in FIGURE 3, the connection using communications link 464 is made between the transport network management system 460 and the source end node 442. In this configuration, the transport network management system 460 has direct communications access to the source end node 442, and indirect communications access, via the transport network 446, with the destination end nodes 444. With continued reference now to FIGURE 5, the format 452' for data communications further includes an optional data field 466 for communicating transport network management system 460 related information from the source node 442 to each of the destination end nodes 444 along with the transmitted sub-node messages. After determining which particular sequenced order 472 of the agreed distribution pattern is be used for a given destination end node 444, the transport network management system 460 may communicate that information to the source end node 442 where it is inserted into the optional data field 466 of a communication addressed to that particular destination end node. The optional data field 466 is further used to convey other transport network management system 460 information (such as, for example, operation and maintenance data) from the source end node 442 to the destination end node 444.

Reference is now made to FIGURES 3 and 8 wherein FIGURE 8 shows a block diagram of a communications system 10 (like the network 440 of FIGURE 3) utilizing, by way of an example, an asynchronous transfer mode (ATM) variety packet switched network 12 for its transport network 446. The system 10 includes a plurality of ATM access nodes 14 and user (service) nodes 16 such as the end nodes 442 and 444 external to the ATM transport network 12. The ATM access nodes 14 perform pre-shaping flow enforcement functions and are located at the "edges" of the ATM transport network 12 between the user nodes 16 and the ATM transport network "core". At such a location, the access nodes 14 implement protocol functions specific to the information being transported over the network (like flow control and delay equalization). The access nodes 14 and the user service nodes 16 are connected by communications links 18 supporting the transmission of an ATM access compatible, multi-level data bit stream as will be described. The core of the ATM network 12 comprises a plurality (only two shown) of interconnected ATM cross-connect (switching) nodes 20 that perform only simple ATM transport and switching functions. The cross-connect nodes 20 are connected to the ATM access nodes 14 by communications links 22, and are interconnected with each other by communications links 24. The links 22 and 24 support the transmission of basic information units (cells) through the ATM network 12 at a bit rate in accordance with well known ATM standards and protocols. This "core and edge" principle for building an ATM network 12 makes it relatively simple to introduce new services as the specific service dependent functions are handled external to the ATM network in the ATM access nodes 14, with the ATM network itself solely being responsible for routing and transporting service data.

With reference now to FIGURE 9, the basic information transfer unit within the ATM network 12 is a small, fixed size packet commonly referred to as an ATM cell 26. The fixed length of the ATM cell 26 is fifty-three bytes (or octets) divided into a five octet header field 28 and a forty-eight octet information (payload) field 30. The header field 28 contains, among other things, information identifying the ATM cell 26 and specifying the routing of the cell through the ATM network 12. The routing information comprises a virtual path identifier (VPI) and a virtual channel identifier (VCI). A virtual path comprises a bundle of multiplexed circuits between two termination points at each ATM node and is identified by the virtual path identifier in the ATM cell header field 28. The virtual path concept allows multiple virtual channels through the ATM network 12 to be handled as a single unit. The virtual channel is identified by the virtual channel identifier in the ATM cell header field 28.

The payload field 30 of the ATM cell 26 typically carries user data. In addition to the ATM cells 26 which carry user data, other cells having the same fixed size are defined for use in the ATM network 12 for signaling and maintenance. The signaling cells are used to set up a service, for example, comprising a connection through or outside of the ATM network 12. The maintenance cells are used to supervise the virtual paths and virtual channels through the ATM network 12. Idle cells, also having the same fixed size, may be used to fill the transmission capacity of the ATM network 12 up to the transmission bit rate limit of the physical medium. Reference is now again made to FIGURES 3 and 8. Data received over communications links 18 by the ATM access nodes 14 at the edge of the ATM network 12 must be converted to the ATM cell 26 fixed size format of FIGURE 9 (and vice versa, as appropriate). This is accomplished by a user-to-network interface (UNI) 32. The user-to-network interface 32 implements an ATM adaptation layer (AAL) which performs a mapping between the format of the data carried over the communications links 18 and the information field 30 of the ATM cell 26. Some examples of the functions provided by the ATM adaptation layer are convergence, segmentation and reassembly, variable length packet delineation, sequence numbering, clock recovery and performance monitoring. The ATM adaptation layer is an important part of the user-to-network interface 32 because adaptation between the data on link 18 for the user service external to the ATM network 12 and the ATM cell 26 on link 22 to allow for service independent ATM data transport. Thus, the interface

32 further functions to make the connection to the physical media of the communications link 22. The identifier "UNI/ATM/PHY" for the interface 32 accordingly refers to the UNI operation of converting to and from the ATM cell format (ATM) and inserting and extracting cells with respect to the physical medium (PHY) of the ATM network.

The communications system 10 further includes a transport network management system (TNMS) 460 to process and provide operation and maintenance (O&M) information regarding the communications system 10 in general, as well as the ATM network 12 in particular. As discussed above, the transport network management system 460 further functions to select the particular sequenced order 472 of the agreed distribution pattern used by the end nodes 442 and 444. It will be noted that the transport network management system 460 is connected to only a single ATM access node 14 via a communications link 464. This is because it is through that single ATM access node 14 and the ATM network 12 that the transport network management system 460 has access for communications to each of the access nodes

14, user service nodes 16 and ATM operation and maintenance of the switching nodes 20.

The communications system 10 implements an agent manager concept with respect to the operation and maintenance functionality. Operation and maintenance managed objects (data or information relating, for example, to performance management, fault management, security management and configuration management) concerning the access nodes 14 themselves and the ATM transport network 12 (and its cross-connect nodes 20) are stored in a local database memory (dbm) 31 associated with each access node. Similarly, operation and maintenance managed objects concerning the user nodes 16 themselves (such as the particular sequenced order 472 of the agreed distribution pattern is to be used at the end nodes 442 and 444) are stored in an associated local data base memory (dbm) 33. Management of the data stored within the data base memories 31 and 33 for the access nodes 14 and user nodes 16, respectively, is performed by an agent functionality 35. The transport network management system 460 includes a global data base memory (dbm) 37 for storing operation and maintenance managed objects relating to the communications system 10 as a whole. Management of this data is performed by a manager functionality 39.

Responsive to requests from the manager functionality 39, the agent functionalities 35 retrieve operation and maintenance data from the data base memories 31 and 33 for forwarding and storage in the global data base memory 37. Alternatively or additionally, and further on a periodic basis or in response to a change in status, the agent functionality 35 retrieves operation and maintenance data from the data base memories 31 or 33, and refreshes the data stored in the global data base memory 37.

Reference is now made to FIGURE 10 wherein there is shown a multi-level data bit stream basic block 38 which is transmitted over the communications links 18 between the access nodes 14 and the user service nodes 16. The bit stream basic block 38 includes a data portion 40 wherein service data (comprising addressing information and message) relating to the user nodes 16 is carried. The bit stream basic block 38 further includes an embedded operation channel (EOC) 42 which contains the operation and maintenance data associated with transport network management system 460 operation. It is through use of this embedded operation channel 42 that the transport network management system 460 can have access to each of the nodes of the communications system 10 while only being connected to a single access node 14 and offer all of the functionality currently described under TMN Standard M.3010. An operation and maintenance flag within the embedded operation and maintenance channel 42 further helps in system 10 determination of the beginning of another bit stream basic block 38.

With reference now again to FIGURE 8, the ATM access node 14 inserts and extracts information to and from the embedded operation channel 42 of the bit stream W ^YvO^j 99^y/^/1ⁱ4w959 PCT/SE98/01594

- 17 - basic block 38. The extracted information from the embedded operation channel 42 comprises information received from transmissions either over the ATM network 12 or from the connected to user service node(s) 16 or access nodes 14 for processing by the transport network management system 460. The inserted information into the embedded operation channel 42 comprises information received from the transport network management system 460 to be transmitted either over the ATM network 12 or to the connected to user service node(s) 16 or access nodes 14.

In response to bit stream basic blocks 38 received over communications link 18, the ATM access node 14 further functions in accordance with its ATM adaptation layer to segment the data portion 40 and embedded operation channel 42 into segments of an appropriate byte length to fit within the payload portion 30 of one or more ATM cells 26 (see, FIGURE 9). The ATM access node 14 further determines the destination for the received bit stream basic blocks 38 (from the included addressing data) and processes routing table derived addressing information in the header portion 28 of the ATM cells 26 which include the segmented data. The generated ATM cells 26 are then output from the ATM access node 14 over communications link 22 in accordance with any specified flow restrictions for transmission over the ATM network 12 to the destination translated by each ATM node according to a given routing algorithm.

An opposite procedure is followed with respect to ATM cells 26 received from the ATM network 12 over communications link 22. The ATM access node 14 identifies from the header 28 of the received ATM cell 26 and a destination routing table the particular user service node 16 to which the data in the payload portion of that ATM cell is intended for delivery. From the payloads 30 of the received ATM cells 26, the ATM access node 14 uses the ATM adaptation layer to construct the bit stream basic block(s) 38 needed to convey the information. The bit stream basic block(s) 38 are then transmitted to the appropriate identified destination user service node 16 via communications link 18.

The user service nodes 16 may not be located physically close to the ATM access node 14. To account for this, both the user service node 16 and the ATM access node 14 include a line interface 44 that facilitates bit stream basic block data transmission over certain types of communications links 18 within communications systems better suited for last mile communications. Such communications systems include by way of example asymmetric digital subscriber line (ADSL); hybrid fiber coaxial (HFC); fiber optic transport system (FOTS); fiber in the loop (FITL); category 3 unshielded twisted pair (UTP) cable; or a scalable inversely multiplied (e.g., seven times) Tl connection. Reference is now again made to FIGURE 10. The bit stream basic block supports transmission at a plurality of rates, and thus may be configured to include at least one and perhaps a plurality of sub-blocks 46. Each sub-block 46 is at the appropriate repetition rate for the data being transmitted over a plurality of channels. Thus, each sub-block 46 includes a data portion 48 for communicating the plural channel communications data. The sub-blocks 46 still further include uniformly spread delimiting bits 50 (indicated by tick marks within the data portions 48) for assisting in the performance of add/drop multiplexing and/or digital cross-connection functions with respect to the plural transmitted channels. The delimiting bits 50 identify particular ones of the plural channels which may be added or dropped from the data stream in order to use these particular channels at the given local user service nodes 16. The delimiting bits 50 may further be used to identify the various sub-data fields 458' (FIGURE 6) in a communication including plural sub-node messages as previously described. Because the delimiting bits 50 comprise a portion of the bit stream basic block 38, that information may be transmitted from one user service node 16 or ATM access node 14 across the ATM network 12 for implementation at another user service node.

Reference is now made to FIGURE 11 wherein there is shown a communications line diagram illustrating the connections and an example of associated transmission bit rates for a given communication handled by the communications system of FIGURE 8. Communications between the access nodes

14 and the user nodes 16 are transmitted at a rate of n x 10 Mbps using the 10 Mbps bit stream basic block shown in FIGURE 10. The 10 Mbps bit stream basic block supports data/video transmissions as well as plural sub-rates for multi-channel communications, delimiting bits for controlling channel add/drop multiplexing, digital cross-connection functions and/or plural sub-node message distribution by the user nodes 16, and an embedded operation channel for monitoring and controlling communications system operation and maintenance. Communications between the access nodes 14 and the switching nodes 20 of the ATM network 12 occur at a conventional ATM bit rate of, for example, 155 Mbps using the ATM cells 26 (FIGURE 9). The communications links 24 between the switching nodes 20 of the ATM network 12 also utilize the ATM cells 26 for transmitting information, but the rate may be much higher than over the links 22 at, for example, 2.4 Gbps (gigabits per second). A connection is also made between one of the access nodes 14 and the transport network management system 460 communicating operation and maintenance information to be inserted into and extracted from the embedded operation channel at a rate of m x 8 Kbps. Referring now to FIGURE 12, there is shown a block diagram of a portion of a cellular telecommunications system 120 utilizing the network 440 configuration of FIGURE 3 and the communications system 10 of FIGURE 8. The user service node 16 on one side of the transport network comprises the telephone exchange (mobile switching center) 122 for the cellular communications system 120 (e.g., the source end node 442 of the network 440). On the other side of the transport network, the user nodes 16 comprise at least one base station concentrator 124 (e.g., the destination end node 444) connected to base stations 130 (e.g., the sub-nodes 448) through which mobile stations 126 engage in radio commumcations over a plurality of traffic channels 128. Communications between the exchange 122/442 and the access node 14, and between the base station concentrators 124/444 and the access nodes, occur over links 18 using the previously described bit stream basic blocks in a multi-level bit stream communication. With the use of ATM adaptation layer segmentation and reassembly in the access nodes 14, the multi-level bit stream communication, including its embedded operation channel and delimiting bits, is transmitted across the ATM network 12 using ATM cells. Using the embedded operation channel, the transport network management system 460 performs connection maintenance, performance monitoring, path tracing, service management and testing over the ATM network 12 and with respect to the access nodes 14 and the user nodes 16 comprising the exchange 122, the base station concentrator 124 and base stations 130. Furthermore, using the included delimiting bits and instructions contained within the embedded operation channel, the base station concentrator 124 performs add/drop " ^,TOy PCT/SE98/01594

-20 - multiplexing, digital cross-connection functions and/or plural sub-node message distribution with respect to channels and communications.

While not described in detail herein, a description of the operation of the ATM access node 14 and transport network management system 460 may be obtained by reference to previously filed, commonly assigned, co-pending Application for Patent

Serial Number 08/615,096, entitled "SYSTEM SUPPORTING VARIABLE BANDWIDTH ASYNCHRONOUS TRANSFER MODE NETWORK ACCESS FOR WIRELINE AND WIRELESS COMMUNICATIONS" filed October 28, 1996, as well as previously filed, commonly assigned, co-pending Application for Patent Serial Number 08/757,581, entitled "SYSTEM AND METHOD FOR THE

COMMUNICATION OF OPERATION AND MAINTENANCE, ADMINISTRATION AND PROVISIONING INFORMATION OVER AN ASYNCHRONOUS TRANSFER MODE NETWORK" filed November 27, 1996, the disclosures of which are incorporated by reference herein. Although preferred embodiments of the method and apparatus of the present invention have been illustrated in the accompanying Drawings and described in the foregoing Detailed Description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the spirit of the invention as set forth and defined by the following claims.

Claims

W wOw 9 y9//1i4^95s9sj PCT/SE98/01594- 21 -WHAT IS CLAIMED IS:

1. A communications system, comprising: a source end node originating communications containing messages; a destination end node to which the source end node originated 5 communications are addressed; a transport network over which the communications are transmitted from the source end node to the destination end node; and a plurality of non-addressable destination sub-nodes connected to the destination end node; o wherein certain ones of the destination sub-nodes are intended destinations for the messages of the source end node originated communications; and wherein the destination end node distributes the messages from the received source end node originated communications to the certain ones of the destination sub- nodes in accordance with a predetermined message distribution pattern.

5 2. The system of claim 1 wherein each source end node originated communication includes a single sub-node message intended for a certain one of the destination sub-nodes, and where the plural source end node originating communications are transmitted in accordance with the predetermined message distribution pattern.

0 3. The system of claim 2 wherein the predetermined message distribution pattern has a particular sequenced order relating to certain ones of the plurality of destination sub-nodes, and the source end node originated communications, each including a single sub-node message for a certain one of the destination sub-nodes, are sent following that particular sequenced order.

4. The system of claim 1 wherein each source end node originated communication includes a plurality of messages intended for the certain ones of the destination sub-nodes, and where the plural messages are included within each communication in accordance with the predetermined message distribution pattern.

5. The system of claim 4 wherein the predetermined message distribution pattern has a particular sequenced order relating to certain ones of the plurality of destination sub-nodes, and the plural sub-node messages are included in each source end node originated communication following that particular sequenced order.

6. The system of claim 5 wherein the plural sub-node messages in each source end node originated communication are delimited from each other using delimitation markers.

7. The system of claim 1 wherein the source end node and destination end node agree upon the predetermined message distribution pattern.

8. The system of claim 1 further including a transport network management system connected to at least one of the end nodes, the transport network management system selecting for the source end node and destination end node the predetermined message distribution pattern.

9. The system of claim 8 wherein the transport network management system selected message distribution pattern is communicated between the source end node and destination end node.

10. A method for distributing messages contained in communications received by an addressee destination end node, that addressee destination end node connected to a plurality of non-addressable sub-nodes, comprising the steps of: extracting the messages from the received communications; and distributing the messages to the proper intended recipient ones of the non- addressable sub-nodes in accordance with a predetermined message distribution pattern.

11. The method of claim 10 wherein each received communication includes a single sub-node message intended for a certain one of the non-addressable sub- nodes, the single sub-node message distributed to the certain one of the non- addressable sub-node in accordance with the predetermined message distribution pattern.

12. The method of claim 11 wherein the predetermined message distribution pattern has a particular sequenced order relating to the plurality of non- addressable sub-nodes, the received communication including a single sub-node message for a certain one of the destination sub-nodes having been sent following that particular sequenced order.

13. The method of claim 10 wherein each received communication includes a plurality of messages intended for the non-addressable sub-nodes, the plural messages included within each communication in accordance with the predetermined message distribution pattern.

14. The method of claim 13 wherein the predetermined message distribution pattern has a particular sequenced order relating to non-addressable sub- nodes, the plural sub-node messages included within in each communication following that particular sequenced order.

15. The method of claim 14 wherein the plural sub-node messages in each source end node originated communication are delimited from each other using delimitation markers.

16. A method for communicating messages from a source end node through an addressable destination end node to a plurality of non-addressable sub- nodes connected to the destination end node, comprising the steps of: formatting communications containing the messages, the communications formatted in accordance with a predetermined message distribution pattern; transmitting the commumcations from the source end node to an addressee destination end node; receiving the communications at the addressee destination end node; extracting the messages from the received communications; and distributing the messages to the proper intended recipient ones of the non- addressable sub-nodes in accordance with the same predetermined message distribution pattern used to format the communications.

17. The method of claim 16 wherein the step of formatting comprises the step of including a single sub-node message intended for a certain one of the non- addressable sub-nodes in each communication, the single sub-node message included within the communication in accordance with the predetermined message distribution pattern.

18. The method of claim 17 wherein the predetermined message distribution pattern has a particular sequenced order relating to the plurality of non- addressable sub-nodes, the step of including further comprising the step of inserting the single sub-node messages into the individual communications following that particular sequenced order.

19. The method of claim 16 wherein the step of formatting comprises the step of including a plurality of messages intended for the non-addressable sub-nodes in each communication, the plural messages included within each individual communication in accordance with the predetermined message distribution pattern.

20. The method of claim 19 wherein the predetermined message distribution pattern has a particular sequenced order relating to non-addressable sub- nodes, the step of including further comprising the step of inserting the plural sub- node messages into each individual communication following that particular sequenced order.

21. The method of claim 21 wherein the step of formatting further includes the step of including delimitation markers between the individual plural sub-node messages in each source end node originated communication.

22. A cellular commumcations system, comprising: a mobile switching center generating base station messages that are contained in originated communications; a base station controller to which the mobile switching center originated communications are addressed; a transport network over which the communications are transmitted from the mobile switching center to the base station controller; and a plurality of non-addressable base stations connected to the base station controller; wherein the base station controller distributes the base station messages contained in the received mobile switching center originated communications to the non-addressable base stations in accordance with a predetermined message distribution pattern.

23. The system of claim 22 wherein each originated communication includes a single base station message intended for a certain one of the non- addressable base stations, and wherein the plural originating communications are transmitted in accordance with the predetermined message distribution pattern.

24. The system of claim 23 wherein the predetermined message distribution pattern has a particular sequenced order relating to certain ones of the plurality of non- addressable base stations, and wherein the originated communications, each including a single base station message for a certain one of the non-addressable base stations, are sent following that particular sequenced order.

25. The system of claim 22 wherein each originated commumcation includes a plurality of base station messages intended for the certain ones of the non- addressable base stations, and wherein the plural base station messages are included within each communication in accordance with the predetermined message distribution pattern.

26. The system of claim 25 wherein the predetermined message distribution pattern has a particular sequenced order relating to certain ones of the plurality of non- addressable base stations, and wherein the plural base station messages are included in each originated communication following that particular sequenced order.

27. The system of claim 26 wherein the plural sub-node messages in each source end node originated communication are delimited from each other using delimitation markers.

28. The system of claim 22 wherein the mobile switching center and base station controller agree upon the predetermined message distribution pattern.

29. The system of claim 22 further including a transport network management system connected to at least one of either the mobile switching center or the base station controller, the transport network management system selecting for the mobile switching center and base station controller the predetermined message distribution pattern.

30. The system of claim 29 wherein the transport network management system selected message distribution pattern is communicated between the mobile switching center and base station controller.