DE19901204C2 - Method for realizing multiple point codes in a switching center - Google Patents

Description

Communication networks or networks connect for the night exchange of information (e.g. language, data, text or images) in usually at least two subscriber terminals over meh rere line sections and exchanges with each other. In connection control or connection establishment and when using service features are between the Switching agencies to transmit tax information. Ins special digital, computer-controlled communication networks offer one compared to analog communication networks much higher scope of services, which is why in digital, computer-controlled communication networks a new, powerful signaling system was introduced.

The CCITT (now ITU, International Telecommunication Union) has therefore the Central Signaling System No. 7 (CCS7) spec which is suitable for use in digital networks or Networks is optimized.

In contrast to the usual channel-based characters With the CCS7, the signaling messages are sent via separa led signaling routes. A signaling range (link) can use the signaling messages for many users transport channels (trunk).

The signaling lines of the CCS7 connect in one communication cation network signaling points or signaling nodes with each other. The signaling points and the signaling ranges thus form an independent signaling network or signalization rungsnetz, the Nutzkanalnetz or the Nutzkanalnetzwerk is superimposed. The signaling endpoints are the sources and Lower signaling traffic and be in a communica network primarily through the exchanges  realized. The signaling transfer points convey received signaling messages based on the destination address (DPC, De station point code) to another signal transfer point or to a signaling end point. In one time Chengabetransferpunkt does not find any mediation signaling messages instead. A signal transfer point can be in a signaling end point (e.g. one Exchange) or its own node in the signaling network. Depending on the size of the network or of the network are one or more levels of signaling transfer points possible.

All signaling points in a given signaling network (ITU network) are part of a framework defined by the ITU Numbering plan using, for example, a 14-bit point code (PC, Point Code) and can be identified in one go targeted character unit (MSU, Message Signal Unit) can be addressed.

FIG. 4 shows a simplified block diagram of a conventional communication network. In Fig. 4, the reference numeral 1 denotes a switching center (VST), which is located in the city of Munich, for example, and has a point code PC of 6000. The digits (14 bits) of such a point code PC indicate the maximum number of exchanges in a national network and are usually 14 bits. Exceptions to this are the countries USA with 24-bit ANSI standard and China with 24-bit ITU standard. Thanks to these point codes PC, which are assigned throughout the network, a clear addressing of all switching centers existing in the network is possible.

In Fig. 4 such subscriber terminals designate the Be reference numerals 9 and 10 , which are connected via a 2-wire line with their associated switching centers. The reference numeral 2 designates a further exchange, which is located, for example, in the city of Stuttgart and has the point code PC (or the address) of 7000. Each of these exchanges 1 and 2 has a message transfer part 3 and 4 (MTP, Message Transfer Part). The reference characters Chen 5 , 6 , 7 and 8 denote signaling transfer points, such as are integrated, for example, in further exchanges. Such exchanges can be located in Nuremberg, Frankfurt, Mannheim and Karlsruhe, for example, and have the associated point codes 6001 , 6002 , 7001 and 7002 . In FIG. 4, dashed lines also denote CCS7 signaling lines (link) and solid lines CCS7 useful lines (trunk).

To set up, for example, a voice connection from the subscriber terminal 9 to the subscriber terminal 10 via the CCS7 useful lines (trunk), approximately 20 message sign units (MSU, message signal unit) are necessary, which via the dashed CCS7 signaling lines (link) and the intermediary switching centers 5 , 6 , 7 and 8 are saved and transmitted in a specific order.

Fig. 5 shows a section of such a message sign unit MSU, as it will be transmitted in the signaling network. Here, the reference number 11 denotes 14 bit origin point code (OPC, origination point code) and the reference number 12 14 bit destination point code (DPC, destination point code). The origin point code OPC corresponds to an origin address in the signaling network, while the destination point code DPC indicates the destination address. In the communication network according to FIG. 4, the origin code would therefore have the value 6000 for the switching center 1 in Munich and the destination point code the value 7000 for the switching center 2 in Stuttgart when establishing a connection from the subscriber terminal 9 to the subscriber terminal 10 . A plurality of message drawing units MSU would consequently be forwarded via the signaling network to establish the connection, the message drawing unit MSU according to FIG. 5 having the original code OPC and the destination point code DPC for unambiguous assignment.

Referring to FIG. 5, reference numeral 13 designates a number of bits in the message signal unit MSU, the drying, the Netzken (NI, Network Identification) allow. According to the ITU standard, such a network identifier NI consists of two bits and thus indicates the four separate ITU networks INat0, INat1, Nat0 and Nat1.

With the help of this network identifier every exchange can un separate different ITU networks exactly like it for example to separate the national network (Nat0) from international network (INat0) is necessary. The network identifiers INat1 and Nat1 can be used as protective networks or separation networks used to the extremely sensitive Signali nation data in the different networks to separate.

With the loss of the monopoly in the telecommunications sector There has recently been a rich need for different networks to connect providers to a single exchange. For security reasons, the respective networks must be the network providers, however, are precisely addressable and from the existing ones Signaling networks can be separated, which is why in the mediator the need for additional point codes.

There is also an increasing need for a network console dation, d. H. a summary of exchanges, in order to save money. At a derar combining two or more exchanges len, however, there is also the need for more subject point code can be implemented in a switching center must, since the point codes already existing in a network (Addresses) can never be changed for cost reasons allowed to. Since the exchange in the network essentially consists of one Table mapping, such a change from  Point codes an inefficient change effort in the respective tables of the various exchanges on the network cause.

In the same way, however, the realization of one Multiple point codes in one exchange are the same measure costly modification or new creation of existing switching hardware and software.

The invention is therefore based on the object of a method for realizing multiple point codes in one exchange to specify a minimum and cost-effective permanent modification of existing switching is enough.

This object is achieved with the measures of Pa claim 1 solved.

In particular, by adapting a network identifier in an unused message transfer section to a network identifier of a used message transfer section, assigning a new point code for the unused message transfer section and switching a loop between the used and unused message transfer sections a multi-point code can be realized in the exchange in an extremely simple and cost-effective manner. This implementation of multi-point codes is very important in the alternative carrier market for the following reasons:

• 1. A remote controlled exchange (RSU) is a extraordinarily interesting product for network consolidation, However, this requires a separate address (point code) for each RSU. Especially in the future a network operator in Germany is only recognized as such (and thus in Ge cheap interconnection tariffs) if one Minimum number of POI (Point of Interconnection) for network connection  available. For long distance carriers it seems for example, the demand for 23 POIs to prevail. To avoid difficulties, all POIs should be used with different target point codes (DPC) can be addressed.
• 2. In the reseller process, an exchange is operated by two network operators (carriers) with different Carrier access code (CAC) used. However, certain network providers will only be in the future agree to an interconnection if every CAC also with can be addressed with its own destination code.
• 3. For some network operators, the capacity at the POI of 4096 user channel lines is insufficient, which can be set up with a maximum of one source code-destination code combination (CIC 12 bits long).

Advantageous refinements of the Invention marked.

The invention is described below with reference to Embodiments with reference to the drawing described in more detail.

Show it:

Fig. 1 is a simplified block diagram of a signaling network according to a first embodiment;

Fig. 2 is a simplified block diagram of a conventional communication network to be consolidated;

Fig. 3 is a simplified block diagram of a consolidated communications network according to a second embodiment;

Fig. 4 is a simplified block diagram of a conventional communication network; and

Fig. 5 shows a detail of the signaling network messages transmitted character unit.

Fig. 1 shows a simplified block diagram of part of a communication network according to a first exemplary embodiment. In Fig. 1, the same reference numerals designate the same or similar functional elements as in Fig. 5. A subscriber terminal is connected via a 2-wire line to a switching center (VST) 1 of a network provider Y. The point code PC (or the address) of the switching center 1 has the value 6000. The reference symbol 3 'denotes a message transfer part (MTP) in which a multiple point code is implemented. The reference numeral 7 'denotes a further switching center of the network provider Y, while the reference symbol 5 ' denotes a switching center of a network provider X. The network provider X to FIG. 1 in the same ITU signaling network such as the network provider Nat0 Y can work.

For a network operator, it is in the course of liberalization very important to using the other alternative network operators With the help of different point codes distinguish or identify. This applies to both neighboring exchanges of different network driver, as well as when two network operators jointly have a Ver maintain the agency. Because an implementation of Multiple point codes per signaling network very extensive changes of existing software (and possibly even Hardware) would mean, the invention uses the be Existing resources in a ITU standard rea lized exchange. An exchange can Set up flexibly with point codes for each ITU network The networks are strictly separated ben. If you do it now (as for example in the EWSD) two ge  separated networks with the same ITU network indicator (network identifier) and to prove different point codes then only the network separation has to be "bridged". According to the present invention, the exploited surprising effect, after which a direct Connection of realized in the exchange different ITU networks against all expectations kidney.

More specifically, a message transfer part 3 'consists of a plurality of message transfer part areas 24 , 25 etc. As already described above, these message transfer part areas define the different ITU networks and are selected by the network identifier NI in the message character unit MSU. The Siemens EWSD exchange V12, for example, has exactly one point code PC (address) per ITU network Nat0, Nat1, INat0 and INat1. Normally, the message transfer part areas 24 , 25, etc. for the ITU networks Nat0, Nat1, INat0 and INat1 are strictly separated in a switching center, since an immediate switching or linking of these networks should under no circumstances be carried out.

According to the present invention, however, this separation of the message transfer subareas 24 and 25 is used for the ITU networks Nat0 and Nat1 in such a way that the network of the network provider X is separated from the network of the network provider Y. Such a separation of the networks of the different providers enables, for example, mutual billing and checking of the transmitted signaling data. A threat to the respective networks is largely excluded.

Such a strict separation of the various networks from different network providers, but based on the same ITU Want to access network Nat0 can be exploited as follows  the existing software and hardware of the intermediary averaging center (VST) can be implemented very easily.

First, a used message transfer part area is selected. Referring to FIG. 1, this is the message transfer part-region 24 which is used by the network provider Y already for the ITU grid Nat0. An unused message transfer part area 25 is then selected, which was originally intended, for example, for the network identifier Nat1 or any other free (internal) network. In the next step, the network identifier Nat1 of the unused message transfer section 25 is adapted to the network identifier Nat0 of the message transfer section 24 used . That is, the message transfer part area 25 is set up or modified in such a way that it identifies itself externally with the network identifier Nat0, although it functions internally in a network-separate manner. This ensures that the strict separation of message transfer part areas 24 and 25 continues to exist internally (as with the ITU networks Nat0 and Nat1). After the network identifier NI has been adapted in the unused message transfer part area 25 , a new point code PC = 5999 is assigned to this area, where the connection point for the network of the network provider X receives a fixedly defined address. Finally a loop 23 is switched to the outputs of the signaling message transfer part-regions 24 and 25, thereby effecting an indirect connection between the un strictly separate se message transfer part-regions 24 and 25th

The loop 23 can be switched, for example, via an external connection cable. The connecting cable can either be a PCM30 cable and can be connected directly to the PCM30 line connections of the exchange, but only the signaling channels are transmitted. On the other hand, the loop can also be established via a direct connection of the signaling terminals without involving the exchange periphery.

There is also the possibility of an internal CCS7 loop via "nailed up" commands to switch, being a software patch is used. However, the invention is not based on this Possibilities limited, but rather includes all Loops that have a transparent data channel for the Signa Data from a used to an unused Allow message transfer part area.

According to the invention, the network provider X can thus as well Network provider Y access the ITU signaling network Nat0 and select the addresses stored there immediately. Out the perspective of the external viewer is thus obtained access to the exchange with multiple points codes, d. H. Addressing with multiple signaling points codes.

FIG. 2 shows a simplified block diagram of a conventional communication network which can be easily consolidated with the present invention. The communication network of FIG. 2 consists of the four Ver switching centers 19, 20, 21 and 22. The exchanges 19 to 22 are connected to one another via CCS7 signaling lines (left) and work with the network identifier NI = Nat0. The switching centers 19 and 22 and the switching centers 20 and 21 are each connected via CCS7 useful lines (trunk).

In the course of a network consolidation, the switching center 20 (PC = B) is now to be operated as a remote-controlled switching center (RSU B) and its switching function is to be integrated in the switching center 19 (PC = A). This results in particular savings in the operating costs of the network providers.

FIG. 3 shows a simplified block diagram of the communication network according to FIG. 2, the required network consolidation being carried out according to the invention. The reference numerals 21 and 22 designate the exchanges with the point codes PC = C and D as in FIG. 2. However, the reference numeral 20 'now designates a remote-controlled exchange RSU B (remote switch unit) in which the intelligent switching functions in the switching center 19 'have been outsourced. It therefore only provides access to the subscriber terminals, but does not otherwise have any complex switching functions.

Due to the fact that the already existing ITU signaling network Nat0 has a large number of switching centers with associated tables or programs, deleting the previous switching center 20 (PC = B) would mean a comprehensive change of all programs or tables in the other switching centers in the ITU signaling network. In order to prevent such expensive reprogramming of existing switching software, there is a need to keep the point code PC of the switching center 20 (PC = B) and to additionally implement it in the switching center 19 with the point code PC = A the need to implement multiple point codes in a central office.

Such a realization of multiple point codes in the switching center 19 'takes place in the same way as in the exemplary embodiment according to FIG. 1. More precisely, the message transfer part MTP of the switching center 19 ' is modified such that an unused message transfer part area 25 has the same network identifier NI = Like the message transfer section 24 already used, Nat0 receives. Then the point code PC associated with the message transfer part area 25 , which initially does not have its own address, is set up with the address or the value B. Finally, a signaling channel of the message transfer part area 24 is switched through to a signaling channel of the message transfer part area 25 via a loop, which results in a transparent transmission of signaling data.

To complete the consolidation according to FIG. 3, it is now only necessary to establish a connecting line 26 between the remote-controlled switching center 20 '(RSUB) and the switching center 19 ' with multiple point codes, provided this is not already available. The modified switching center 19 'now works as a host (PC = A) and additionally takes over the switching function of the previous switching center 20 (PC = B). The previous signaling line LS4 (Nat0) according to FIG. 2 is implemented here by the loop 23 according to FIG. 3, while the previous signaling line LS1 (Nat0) according to FIG. 2 is realized by the signaling lines LS1 and LS1 '(Nat0) according to FIG. 3 he sets. The signaling lines LS1 and LS1 'represent a common signaling line with the originating / target objects 21 and 25 , the remote-controlled exchange 20 ' (RSU) remaining transparent and being unable to feed its own signaling.

In the present invention, the message transfer sub-areas for the network identifier NI = Nat0 and NI = Nat1 with connected to each other, but all others can also be used message transfer part areas with another Message transfer part area connected and modified become. The present invention can also applied to a Siemens EWSD-V13 exchange the one with up to 32 different point codes any in the respective ITU network (Nat0, Nat1, INat0 or INat1) can be used. The assignment of internal Multiple networks to the ITU network are flexible existing commands when setting up the network. However, the invention can also be applied to all other intermediaries agencies that strictly separate the Realize ITU networks, and in which a modification of the  network identifiers sent to the outside and the point codes per Message transfer part area is possible.

Claims (5)

1. Method for realizing multiple point codes in a switching center ( 1 ) with a message transfer part ( 3 '; 19 ') for sending / receiving signaling data (MSU) in a plurality of separate message transfer part areas ( 24 , 25 ) for separate signaling networks (Nat0, Nat1, INat0, INat1) with different network identifications (NI) and different or nonexistent point code ( 6000 ; A), consisting of the steps:
Selecting a used message transfer part area ( 24 ),
Detecting a network identifier (NI) of the message transfer part area ( 24 ) used,
Selecting an unused message transfer part area ( 25 ),
Setting up or adapting a network identifier (NI) of the unused message transfer section ( 25 ) to the network identifier (NI) of the used message transfer section ( 24 ),
Assign a new point code ( 5999 ; B) for the unused message transfer area ( 25 ) and
Switching a loop ( 23 ) between the used and unused message transfer part area ( 24 , 25 ). 2. The method according to claim 1, characterized in that the Signaling networks Signaling networks in the central Signaling system No. 7 and the signaling data (MSU) Are message drawing units. 3. The method according to claim 1 or 2, characterized in that the loop ( 23 ) is an external connecting cable. 4. The method according to claim 2, characterized in that the loop ( 23 ) is an internal CCS7 loop. 5. The method according to claim 4, characterized in that the loop ( 23 ) is realized by a software patch.