WO2000042781A1

WO2000042781A1 - Method for implementing multipoint codes in an exchange

Info

Publication number: WO2000042781A1
Application number: PCT/DE2000/000127
Authority: WO
Inventors: Walthari Funk
Original assignee: Siemens Aktiengesellschaft
Priority date: 1999-01-14
Filing date: 2000-01-14
Publication date: 2000-07-20
Also published as: DE19901204C2; CN1337125A; CN100466753C; DE19901204A1; DE10080079D2; BR0007555A

Abstract

The invention relates to a method for implementing multipoint codes in an exchange with which it is possible to e.g. carry out a network consolidation and connect additional network providers in an existing network. A network identifier of a message transfer part area (25) which is not in use is adapted to a network identifier of a message transfer part area (24) which is in use, a new point code is allocated to the message transfer part area (25) which is not in use, and a loop (23) is connected between the used and unused message transfer part area.

Description

description

Method for realizing multiple point codes in a switching center

Communication networks or networks generally connect at least two subscriber terminals to one another via a plurality of line sections and switching centers for the exchange of messages (for example voice, data, text or images). In connection control or connection establishment and in the use of service features, control information is to be transmitted between the switching centers. In particular, digital, computer-controlled communication networks offer a significantly higher scope of services than analog communication networks, which is why a new, powerful signaling system has been introduced in digital, computer-controlled communication networks.

The CCITT (now ITU, International Telecommunication Union) has therefore specified central signaling system No. 7 (CCS7), which is optimized for use in digital networks.

In contrast to the usual channel-based signaling, the signaling messages of the CCS7 are routed via separate signaling paths. A signaling link can carry the signaling messages for many user channels (trunk).

The signaling lines of the CCS7 connect signaling points or signaling nodes with each other in a communication network. The signaling points and the signaling lines thus form an independent signaling network or signaling network which is superimposed on the user channel network or the user channel network. The signaling endpoints are the sources and sinks of the signaling traffic and are used in a communication network primarily by the switching centers realized. The signal transfer points convey received signaling messages on the basis of Zieiaαresse (DPC, De ^¬ stination Point Code) to another signal transfer point or to a signaling endpoint on. At a signal transfer point there is no processing of the signaling messages. A signaling transfer point can be integrated in a signaling end point (e.g. a switching center) or form its own node in the signaling network. Depending on the size of the network or the network, one or more levels of signaling transfer points are possible.

All signaling points in a given signaling network (ITU network) are identified within the framework of a numbering plan defined by the ITU by, for example, a 14 bit point code (PC, point code) and can thus be specifically addressed in a message character unit (MSU, Message Signal Unit) become.

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, for example, in the city of Munich and has a point code PC of 6000. The digits (14 bits) of such a point code PC indicate the maximum number of switching centers in a national network and are usually 14 bits. Exceptions to this are the countries of the USA with the 24-bit ANSI standard and China with the 24-bit ITU standard. Because of the network-wide PC point codes, it is possible to address all switching centers in the network clearly.

In Fig. 4 such subscriber terminals designate the reference numerals 9 and 10 which are connected to their associated switching centers via a 2-wire cable. The reference number 2 designates a further exchange, which is located, for example, in the city of Stuttgart and 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 numerals 5, 6, 7 and 8 denote signaling transfer points, such as are integrated in other switching centers, for example. Such exchanges can be located in Nuremberg, Frankfurt, Mannheim and Karlsruhe, for example, and have the associated point codes 6001, 6002, 7001 and 7002. 4, dashed lines 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 user lines (trunk), approx. 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 drawing unit MSU as it is transmitted in the signaling network. The reference numeral 11 denotes 14-bit origin point code (OPC, origination point code) and the reference numeral 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 a connection was set up from the subscriber terminal 9 to the subscriber terminal 10. A large number 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. has the original code OPC and the target point code DPC.

5, reference numeral 13 denotes a number of bits in the message drawing unit MSU which enable network identification (NI). According to the ITU standard, such a network identifier NI consists of two bits and thus indicates the four separate ITU networks INatO, INatl, NatO and Natl.

With the help of this network identifier, each exchange can separate different ITU networks exactly, as is necessary, for example, to separate the national network (NatO) from the international network (INatO). The network identifiers INatl and Natl can be used here as protective networks or separation networks in order to cleanly separate the extraordinarily sensitive signaling data in the different networks.

With the elimination of the monopoly in the telecommunications sector, there is now a need to connect different network providers to a single exchange. For security reasons, however, the respective networks of the network providers must be precisely addressable and separable from the existing signaling networks, which is why there is a need for further point codes in the switching centers.

Furthermore, there is an increasing need for network consolidation, that is to say a combination of switching centers, in order to thereby save costs. With such a combination of two or more switching centers, however, there is also the need for a multiple point code to be implemented in a switching center, since the point codes (addresses) already existing in a network may not be changed for cost reasons. Since the switching in the network essentially consists of a table assignment, such a change from Point codes cause an inefficient change effort in the jewei ^¬ time tables of different switching Steep the net.

In the same way, however, the realization of one

Multiple point codes in a switching center an equally costly modification or re-creation of the existing switching hardware and software.

The invention is therefore based on the object of specifying a method for realizing multiple point codes in a switching center, in which a minimal and cost-effective modification of existing switching centers is sufficient.

This object is achieved according to the invention with the measures of claim 1.

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 section a multiple point code can be implemented in the exchange in an extremely simple and inexpensive manner. This implementation of multi-point codes is very important in the alternative carrier market for the following reasons:

1. A remote-controlled switching center (RSU) is an extremely interesting product for network consolidation, but the prerequisite for this is a separate address (point code) for each RSU. Especially since in the future a network operator will only be recognized as such in Germany (and thus benefit from the low-cost interconnection tariffs) if a minimum number of POIs (Point of Interconnection) are available to the network provider available. For long distance carriers, for example, the demand for 23 POIs seems to be taking hold. To avoid difficulties, all POIs should therefore be addressed with different destination point codes (DPC).

2. In the reseller process, a switching center is used by two network operators (carriers) with different network operator access codes (CAC, Carrier Access Code). However, certain network providers will only agree to an interconnection in the future if each CAC can also 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 point code-target point code combination (CIC 12 bits long).

Advantageous embodiments of the invention are characterized in the subclaims.

The invention is described below using exemplary embodiments with reference to the drawing.

Show it:

1 shows a simplified block diagram of a signaling network according to a first exemplary embodiment;

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

3 shows a simplified block diagram of a consolidated communication network according to a second exemplary embodiment; Fig. 4 is a simplified block diagram of a conventional communication network; and

5 shows a section of a message character unit transmitted in the signaling network.

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 to a switching center (VST) 1 of a network provider Y via a 2-wire line. 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 symbol 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. 1, the network provider X should be able to work in the same ITU signaling network NatO as the network provider Y.

In the course of liberalization, it is very important for a network operator to differentiate or identify the other alternative network operators using different point codes. This applies both to neighboring exchanges of different network operators, as well as if two network operators maintain one exchange together. Since an implementation of multiple-point codes per signaling network would mean very extensive changes to existing software (and possibly even hardware), the invention makes use of the resources already available in a switching center implemented according to the ITU standard. A switching center can be set up flexibly with point codes (point codes) per ITU network, whereby the networks actually remain strictly separate. If you now manage (as in the EWSD) two separated networks with the same ITU network indicator (network identifier) and different Punktcoαes (point codes) to Delegen, then only the network separation must be "bridged". According to the present invention, the surprising effect is exploited here, according to which a direct connection of different ITU networks implemented by the switching center works against all expectations.

More specifically, a message transfer part 3 'consists of a plurality of message transfer part areas 24, 25 and. s. w. As already described above, these message transfer part areas define the different ITU networks and are selected by the network identifier NI m of the night character unit MSU. The Siemens EWSD exchange V12, for example, has exactly one point code PC (address) per ITU network NatO, Natl, INatO and INatl. Normally, the message transfer part areas 24, 25 and. s. w. for the ITU networks NatO, Natl, INatO and INatl strictly separated in a switching center, since these networks should never be switched or linked directly.

According to the present invention, however, this separation of the message transfer part areas 24 and 25 is used for the ITU networks NatO and Natl 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. This largely excludes any risk to the respective networks.

Such a strict separation of the different networks from different network providers, who, however, want to access the same ITU network NatO, can be exploited as follows the already existing software and hardware of the exchange (VST) can be realized very easily.

First, a used message transfer part area is selected. 1, this is the message transfer part area 24 which is already used by the network provider Y for the ITU network NatO. An unused message transfer part area 25 is then selected, which was originally intended for the network identifier Natl or any other free (internal) network, for example. In the next step, the network identifier Nat1 of the unused message transfer section 25 is adapted to the network identifier NatO 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 NatO, although it functions internally in a network-separated manner. This ensures that the strict separation of message transfer sections 24 and 25 remains intact internally (as with the ITU networks NatO and Natl). After the network identifier NI has been adapted in the unused message transfer area 25, a new point code PC = 5999 is assigned to this area, as a result of which the connection point for the network of the network provider X receives a fixedly defined address. Finally, a loop 23 is connected to the signaling outputs of the message transfer part areas 24 and 25, as a result of which there is a direct connection between the message transfer part areas 24 and 25, which are strictly separate per se.

The loop 23 can be switched, for example, via an external connecting cable. The connection 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 times without involving the exchange periphery. It is also possible to switch an internal CCS7 loop using "nailed up" commands, using a software patch. However, the invention is not limited to these possibilities, but rather embraces all of them

Loops that allow a transparent data channel for the signaling data from a used to an unused message transfer part area.

According to the invention, the network provider X, like the network provider Y, can therefore access the ITU signaling network NatO and select the addresses stored there directly. From the point of view of the external viewer, the access to the exchange with multiple point codes, i.e. Addressing with several signaling point codes.

FIG. 2 shows a simplified block diagram of a conventional communication network which can be easily consolidated with the present invention. The

2 consists of the four switching centers 19, 20, 21 and 22. The switching centers 19 to 22 are connected to one another via CCS7 signaling lines (left) and operate with the network identifier NI = NatO. The exchanges 19 and 22 and the exchanges 20 and 21 are each connected via CCS7 user lines (trunk).

In the course of a network consolidation, the exchange 20 (PC = B) is now to be operated as a remote-controlled exchange

(RSU B) are operated and their switching function are 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 was carried out according to the invention. The reference symbols 21 and 22 designate the switching centers with the point codes PC = C and D, as in FIG. 2. However, the reference symbol 20 'now designates a remote-controlled switching center RSU B (remote switch unit) in which the intelligent switching functions are transferred to the switching center 19'. were 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 existing ITU signaling network NatO has a large number of switching centers with associated tables or programs, deleting the previous switching center 20 (PC = B) would result in a comprehensive change of all programs or tables in the other switching centers in the Require ITU signaling network. In order to prevent such costly 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. There is thus again the need to implement multiple point codes in a switching center.

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 part area 24 that has already been used, NatO then receives the point code PC associated with the message transfer part area 25, which initially does not have its own address, with the address or the value B. Finally, a signaling channel of the message transfer part area 24 is passed through a loop to a signaling channel of the message transfer part area 25 switches, 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 (NatO) according to FIG. 2 is realized here by the loop 23 according to FIG. 3, while the previous signaling line LSI (NatO) according to FIG. 2 is done by the signaling lines LSI and LSI '(NatO) 3 to be replaced. The signaling lines LSI and LSI 'represent a common signaling line with the originating / target objects 21 and 25, the remote-controlled switching center 20' (RSU) remaining transparent and being unable to feed its own signaling.

In the present invention, the message transfer part areas for the network identifier NI = NatO and NI = Natl were connected to one another, but it is also possible to connect and modify all other unused message transfer part areas with a further night transfer part area. In addition, the present invention can also be applied to a Siemens EWSD-V13 routing point, in which up to 32 different point codes can be used in any given ITU network (NatO, Natl, INatO or

INatl) can be used. The assignment of internal multiple networks to the ITU network is done flexibly with existing commands when setting up the network. However, the invention can also be applied to all other exchanges which implement a strict separation of the ITU networks and in which a modification of the externally sent network identifiers and the point codes per message transfer part area is possible.

Claims

claims

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 (NatO, Natl, INatO, INatl) with different network identifiers (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 used message transfer part area (24), 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, that the signaling networks are 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, d a d u r c h g e k e n n z e i c h n e t that the loop (23) is an external connection 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, d a d u r c h g e k e n n z e i c h n e t that the loop

(23) is implemented by a software patch.