Abstract:
In the inventive configuration of a communication relationship, a data packet comprising the respective address information of the communication unit is generated by at least one remote communication device or by at least one communication unit that is assigned to said device and is transmitted to a central communication device via a communication network. Said central communication device selects an assigned communication unit and generates a data packet, which comprises the respective address information of the selected communication unit, said data packet being transmitted to the remote communication device. The communication relationship between the addressed communication units is configured with the aid of the transmitted or exchanged address information via the communications network. The inventive method can be advantageously used during the initialization of a communications network, e.g. a booting of the system, as no communication with a management system (central or remote) is possible during this period.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is the US National Stage of International Application No. PCT/DE2003/003898, filed Nov. 25, 2003 and claims the benefit thereof. The International Application claims the benefits of German application No. 10255159.6 filed Nov. 26, 2002, both applications are incorporated by reference herein in their entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The invention relates to a method for the automatic configuration of communication relationships between communication units situated in a packet-oriented communications network.  
       SUMMARY OF THE INVENTION  
       [0003]     In the interests of optimizing current communications networks, in particular broadband subscriber access networks (also called access networks), a large number of subscribers are to be guaranteed low-cost access to both narrowband and broadband services—e.g. video-on-demand. In the course of this optimization, the technological and economical cost of implementing network devices that can be situated in current communications networks may be reduced by using technologies that have not been specifically developed for broadband subscriber access networks, but for mass markets (e.g. personal computers). An example of such a widespread and correspondingly further developed technology is the “Ethernet”, which has been standardized according to IEEE standard 802.3 and which provides a frame-oriented or packet-oriented and connectionless transmission method. In network devices that can be situated in current communications networks, such as—for example—multiplex devices, it is known for data cells, for example those configured according to asynchronous transfer mode (ATM)—also called ATM cells—as well as time-slot-oriented information (e.g. TDM or PCM structures, Pulse Code Modulation) to be switched, via an Ethernet situated locally in the network device, between remote subscriber line modules situated in the network device and at least one central unit or module having central functions. The Ethernet may be used both as a “wiring” or “backplane” in a card rack for bridging short distances, and as a comprehensive communications network for bridging larger distances.  
         [0004]     In the transition from traditional, circuit-switching or time-slot-oriented communications networks to packet-oriented communications networks, particularly on communications networks according to IEEE standard 802.3, the change in transmission method also entails changes in the addressing and configuration of the system components involved. The following system structure is frequently used in current communications networks: 
        a central module—hereinafter also called a central communication device—with a plurality of assigned communication units providing Ethernet interfaces, for example—hereinafter also called transformer modules—which are connected via a central switching device—e.g. Ethernet switch—to a packet-oriented communications network—e.g. Ethernet,     a plurality of remote modules—hereinafter also called remote communication devices—each of which likewise incorporates at least one communication unit providing an Ethernet interface—a transformer module—in which at least one communication unit is connected via a switching device—in this case an Ethernet switch—to the communications network, and—via said communications network—to the central communication device.        
 
         [0007]     In the system structure described above, the object is to facilitate a functional startup of the arrangement or system—i.e. to boot it up—in such a way that a logical point-to-point connection is set up between communication units or transformer modules assigned in each case to a remote module and to the central module.  
         [0008]     A conventional solution option consists in setting up the individual configuration of the respective point-to-point connections via the communications network by means of local management consoles that can be connected to the communication devices. However, in a system covering a large geographical area, with many remote communication devices, this cannot be done by network operators due to the increased cost. The alternative option of having a fixed configuration is likewise not possible, since the assignment is to be effected dynamically.  
         [0009]     The object of the invention is to improve the configuration of communication relationships between central and remote communication devices situated in a communications network, such that no interaction with a central management system is necessary. This object is achieved by the claims.  
         [0010]     In the inventive method, communication relationships are configured between communication units situated in a packet-oriented communications network, assigned to at least one remote and one central communication device, and in each case having communications-network-specific address information. The main aspect of the method according to the invention consists in that a data packet comprising the respective address information of the communication unit is generated by at least one remote communication device or by at least one communication unit that is assigned to said device and is transmitted to the central communication device via the communications network. Said central communication device identifies the address information contained in the incoming data packet, selects at least one communication unit assigned to the central communication device, and assigns the identified address information to the selected communication unit. Furthermore, said central communication device—or at least one selected communication unit—generates at least one data packet which comprises the respective address information of the selected communication unit, and transmits said data packet to the remote communication device via the communications network. The communication relationship between the addressed communication units is configured via the communications network with the aid of the address information transmitted to the central and remote communication device.  
         [0011]     The main advantage of the inventive method consists in that no management system (central or remote) is required for the setting up or configuration of communication relationships between communication units—e.g. interface units or transformer modules—situated in a communications network. The inventive method can therefore be used during the initialization of a communications network, e.g.—a system booting, as no communication with a central management system is possible during this period.  
         [0012]     Only after these communication relationships have been set up according to the inventive method is it possible, for example, for the management system to communicate via the communications network via the communication relationships that have been set up. The inventive method makes it possible, at the earliest possible stage during system initialization, for the communication units or modules involved in a communication relationship that is to be set up, to be notified of the respective reciprocal communications-network-specific address information—also called MAC addresses—at runtime, thus facilitating a random assignment for the point-to-point connections.  
         [0013]     The packet-oriented communications network is advantageously configured according to the IEEE standard 802.3. Such communications networks that are based on Ethernet technology are designed for the mass market in local networks (LANs) and are therefore low-cost. With the aid of Ethernet technology, therefore, internally situated communications networks can be used, for example locally in a network device, as cost—effective wiring of—for example—central and remote modules (“backplane”).  
         [0014]     Other advantageous embodiments of the inventive method and a communication arrangement for implementing the inventive method are described in the dependent claims.  
         [0015]     The inventive method is described in greater detail below with the help of two drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]      FIG. 1  shows a communication arrangement, situated in a communications network, for implementing the inventive method, and  
         [0017]      FIG. 2  shows an alternative development version of the communication arrangement shown in  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]      FIG. 1  is a block circuit diagram showing a network device NE that is situated in a subscriber access network or access network ACCESS and configured as a multiplex device, and in which the respective subscribers—not shown—are connected to a higher-level communications network OKN—for example an ISDN communications network—via a plurality of remote modules DBG . . . k situated in the network device NE and via a plurality of subscriber accesses TA or subscriber access lines. An “internal”, packet-oriented communications network EN—hereinafter also called “Ethernet”—which is configured according to IEEE standard 802.3, and via which the respective remote modules DBG 1  . . . k—hereinafter also called remote communication devices—are connected to a central module ZBG—hereinafter also called a central communication device—is situated in the network device NE. The remote communication devices DBG 1  . . . k and the central communication device ZBG each have a switching device SW—hereinafter called the Ethernet switch—which has been adapted to the transmission technology of the communications network EN, whereby said communications devices DBG 1  . . . k, ZBG are connected to the packet-oriented communications network EN via a connection port of the Ethernet switch SW and a connection AD, AZ of the respective communication device DBG 1  . . . k, ZBG, said connection being provided for this purpose.  
         [0019]     In this exemplary embodiment, each remote communication device DBG 1  . . . k has a communication unit KE represented by a transformer module KE. Each transformer module KE implementing the subscriber access incorporates transformation functions for the transition between—for example—time-slot-oriented transmission technology that is implemented on the subscriber access line, and packet-oriented transmission technology—in this case TCM/Ethernet—that is implemented in the communications network. Each transformer module KE is connected to the Ethernet switch SW assigned in the remote communication device DBG 1  . . . k. It should be noted that each remote communication device DBG 1  . . . k may comprise a plurality of such transformer modules or communication units KE.  
         [0020]     It should also be noted, in the event that only one communication unit KE is assigned to the remote communication device DBG 1  . . . k, that the remote communication device DBG 1  . . . k and the assigned communication unit may be logically combined, in other words may be regarded as an identical or logically related unit.  
         [0021]     Furthermore, a plurality of transformer modules or communication units KE, which are each connected to the Ethernet switch SW situated in the central module ZBG, are likewise situated in the central communication device ZBG. All communication units KE have their own address information mac 1 _ 1  . . . k_n, macz 1  . . .  1 —also called a MAC address (Medium Access Control)—which uniquely identifies the respective communication unit KE in the packet-oriented communications network EN. Each communication device DBG 1  . . . k, ZBG that is connected to the packet-oriented communications network EN has a control device STE, which is connected to the components of the respective communication device—and therefore to the respective transformer modules KE and the Ethernet switch SW. The transformer modules KE situated in the central communication device ZBG each have a connection AL, via which the respective transformer modules KE are connected to the higher-level communications network OKN that is configured—in this exemplary embodiment—according to the ISDN transmission method, via corresponding outputs UL in the central communication device ZBG.  
         [0022]     According to an alternative development version illustrated in  FIG. 2 , the outputs AL of the transformer modules KE situated in the central communication device ZBG are taken back to corresponding ports AP′ of the Ethernet switch SW situated in the central module ZBG, said Ethernet switch SW being connected to the higher-level communications network OKN via further ports AP″. The corresponding configuration transmits information between the transformer modules (KE) and the higher-level communications network (OKN) via the Ethernet switch SW and its connections AP′, AP″ respectively.  
         [0023]     When the arrangement illustrated in the block circuit diagram is started up, communication relationships or logical point-to-point connections, via which the payload information is transmitted following successful startup, are to be set up between the communication units KE situated in the remote and central communication devices.  
         [0024]     The sequence of the inventive method is described in greater detail below: 
    1. In one development version of the inventive method, a freely selectable MAC address iadr—hereinafter also called the initialization address—is defined as being known to all control units STE situated in the respective remote and central communication devices DBG 1  . . . k, ZBG. The time of initialization of the communication arrangement illustrated in the block circuit diagram, also called the system start-up or boot, is considered below. After the initialization of the system or of the communication arrangement, all communication devices DBG 1  . . . k, ZBG connected to the packet-oriented communications network EN behave passively. For the exemplary embodiment, it may also be assumed that—during the system initialization—a communication relationship or logical point-to-point connection kb (many such connections are signified in the block circuit diagram by a dotted double-ended arrow) is to be set up between the transformer module KE situated in the first communication device DBG 1  and a transformer module KE situated in the central communication device ZBG.     2. The control device STE situated in the first remote communication device DGB 1  configures the initialization address iadr as a (temporary) destination MAC address in the communication unit KE assigned to said device. This initialization address iadr is also configured in the assigned Ethernet switch in such a way that the connection port AP that implements the connection to the communications network EN is selected on the network side by said initialization address iadr. Furthermore, all units situated in the communications network EN, such as—for example—switches, are configured by presetting them so that the data packets or Ethernet frames having the initialization address iadr are switched toward the central communication device.     3. The control unit STE situated in the central communication device ZBG configures the initialization address iadr in the relevant Ethernet switch SW as pertaining to precisely one respective output port AP assigned to precisely one transformer module KE, so that a unique switching decision can be made immediately without “flooding” or “learning”. Two development versions are possible according to this exemplary embodiment: firstly, an incoming data packet or Ethernet frame that has the initialization address iadr as the destination address is switched via the transformer module KE and via an interface to the control unit STE, said interface being provided for this purpose, as indicated in the block circuit diagram by the route L 1 , L 2 . In the other version, an Ethernet frame having the initialization address iadr is switched via an interface of the Ethernet switch SW—said interface being specially provided for this purpose—directly to the control unit STE—as indicated in the block circuit diagram by the route L 3 .     4. After the initialization according to step 2, the transformer module KE in the first remote communication device DBG 1  starts to transmit special data packets or Ethernet frames—illustrated schematically in the block circuit diagram by a data packet fr_z—cyclically to the initialization address iadr. These Ethernet frames fr_z may, for example, be configured such that they differ somehow from a normal payload and can therefore be clearly identified as a “handshake”. This may be achieved, for example, by setting a specific value of the “Ethernet type field” defined in the Ethernet standard. Unlike the values already provided or reserved in the standard, this value may be freely selected. Furthermore, the MAC address—in this case mac 1 _ 1 —of the transformer module KE is inserted in the generated Ethernet frames fr_z as the “originating address”.     5. The Ethernet switch SW situated in the first remote communication device DGB 1  forwards the data packet fr_z thus generated to the Ethernet EN via the connection port AP, since this switching decision is clear as a result of step 2.     6. The data packet fr_z switched to the central module ZBG via the communications network EN is received by the Ethernet switch SW situated in the central communication device ZBG, whereby the originating address mac 1 _ 1  contained in the received data packet fr_z is identified or “learnt” and a unique switching decision is likewise made by the Ethernet switch SW on the basis of the configuration described in step 3. The received data packet is forwarded to the control device STE of the central communication device ZBG via one of the configured connection ports AP, either via the illustrated route L 1 , L 2  or via the alternative route L 3 , depending on the version selected.     7. The control device STE situated in the central communication device ZBG extracts from the received data packet or Ethernet frame fr_z the originating MAC address (in this case mac 1 _ 1 ) contained in it, and selects a transformer module KE that is currently unassigned and available in the central communication device ZBG. For this exemplary embodiment it must be assumed that the transformer module KE with the corresponding MAC address macz 1  is selected. The control device STE implements the extracted originating MAC address (mac 1 _ 1 ) in the selected transformer module KE (macz 1 ) as the destination for the transmit direction of the point-to-point connection to be set up. The control device STE also determines the MAC address of the selected transformer module (in this case macz 1 ), which in turn must be communicated to the first remote communication device DBG 1  as the (ultimate) destination.     8. The control device STE situated in the central communication device ZBG generates (for example via the route L 3  illustrated in the block circuit diagram) an equally “special” Ethernet frame as the response to the Ethernet frame emitted by the remote communication device DBG 1 . The destination of this special Ethernet frame or data packet schematically illustrated in the block circuit diagram by a data packet fr_d—is the first remote communication device DBG 1 , or the communication unit or transformer module KE (mac 1 _ 1 ) assigned to said remote communication device DBG 1 —i.e. the MAC address mac 1 _ 1  that has just been learnt is inserted in the generated Ethernet frame fr_d as destination information. Furthermore, the originating MAC address of the transformer module (in this case macz 1 ) selected in step  7  is inserted in the special Ethernet frame fr_d as the originating address. All Ethernet switches SW affected have learnt the MAC address of the transformer module KE assigned to the first remote communication device DBG 1  and are able to make a unique switching decision for the return route.     9. The Ethernet switch SW situated in the first remote communication device DBG 1  extracts from this received data packet or response Ethernet frame fr_d in a similar way to step 3. In this way the control device STE can extract the originating MAC address contained in the Ethernet frame and configure it as the ultimate destination of the point-to-point connection kb to be set up or configured in the transformer module KE assigned to it.     10. The transformer module KE situated in the first remote communication device DGB 1  stops the cyclical emission of Ethernet frames fr_z according to step 4, so that the transportation of the actual payload via the communication device kb, that was set up with the aid of the inventive method, may now commence.    
 
         [0035]     According to an alternative development version of the communication arrangement illustrated in the block circuit diagram, the respective remote communication devices DBG 1  . . . k can each be connected to the central communication device ZBG via a connection line implementing the communications network EN, said connection line VL being indicated in the block circuit diagram by a dotted line. All data packets emitted by the remote communication devices DBG 1  . . . k are automatically switched or routed to the central communication device ZBG via these connection lines VL. It should be noted that the random MAC address or initialization address iadr previously provided for the inventive method is not required in an arrangement of this type, since all data packets are switched or transmitted to the central communication device ZBG from the remote communication devices DBG 1  . . . k via the connection lines without switching decisions, and therefore the initialization address is not required as destination information or routing information for the Ethernet frames. In this development version, therefore, only the MAC addresses of the respective transformer modules KE that represent the end points of the point-to-point connections to be set up—i.e. mac 1 _ 1  . . . k_n, macz 1  . . .  1 —are inserted and transmitted in the described way. The non-use of routing information in Ethernet frames would not, however, conform to the standard (e.g. as per IEEE 802.3), which means that the inventive method could not be implemented with standard-compliant components. A proprietary adaptation—which is associated with higher cost—would be required, while it is nevertheless possible, in this development version, to dispense with any type of management (central or remote).  
         [0036]     The inventive method enables a system configuration to be configured and booted up dynamically without the involvement of a central management system. The method described in greater detail in the exemplary embodiment uses only resources that comply with the Ethernet standard and manages without broadcasts, which—for reasons of clear data separation—is regarded as unsuitable, particularly in the context of communications networks being operated by different network operators. With the exception of the development version described above, the inventive method requires a unique MAC address or initialization address, which is fixed yet freely selectable, in order to configure an essentially unlimited quantity of point-to-point connections.