DE2430958B1 - Line connection method for telecommunications exchanges - esp telephone exchanges systematically avoiding unsuitable connections - Google Patents

Abstract

Any connection through an exchange is defined by its source and/or destination and the exchange network plane which is divided into several categories. A first selector in the exchange has an input and an output for its own category with regard to the network hierarchy. A second selector has an input for each destination defined by a routing digit and an output for a selection series for connections to the required destination such that one line group may be selected which has at least one clear line. The first selector is hardwired and the information is specific for all exchanges and does not need to be changed for addition or removal of line groups. The second is a storage unit which may have its contents altered without changing its construction. This has the advantage that changes in the network such as line group additions or removals are easy to incorporate.

Description

Through the above-mentioned publication and through the magazine SEL-Nachrichten, 1961, (9th year), issue 1, p. 30, it is now known to combine this information in one To put down allocators (correctors) and depending on the

may provide the information required in each case when establishing the connection to inquire. These assigners can use the corresponding keep internal wiring (see SEL-Nachrichten 1959, 7th year, issue 4, p. 181 ff) and as a memory in such a way that the write stored information at any time and without wiring changes, delete and read non-destructively (see DBP 19 17442).

The object of the invention is that of routing to save relevant information as expediently and clearly as possible and the necessary assigners in the various exchanges, if possible uniformly lifted outside, so in the event of changes in the expansion of the switching network the corresponding changes to the relevant information in the folders, if possible can be carried out easily and have the smallest possible scope.

This object is achieved according to the invention in that due to which can be determined with regard to the respective origin and / or destination of a connection Relation of each of the exchanges with respect to each to be switched through Origin and destination defined connection and with regard to the own network level this Switching centers are divided into different categories that in the switching centers a first allocator has an input for the category of its own exchange and has an output for the categories of such exchanges that are outgoing on the category of your own exchange with regard to the structure of the Network hierarchy are generally permitted for further connection establishment, that in the exchanges a second allocator has an input for the respective Direction code determining the destination of a connection and an exit for to a goal-related selection sequence ordered names of all to achieve the selected destination has existing and intended trunk group that these designations individually the respective categories of the over these trunk groups attainable exchanges are attached, and that under these trunk groups according to the target-related selection order one is selected that both at least has a free line as well as one of those from the first assigner as permissible corresponds to the categories marked on the output side.

The invention has the advantage that the network structure concerned Information in the first allocator is uniform for all exchanges and do not need to be changed when creating new trunk groups or when Failure of existing trunk groups in the network. Based on the current status of Connection establishment with regard to the origin and / or destination of the connection give these Information stored in the first allocator indicates which other types of exchanges may be controlled with respect to origin and / or destination. This lets on simply take into account the network structure of the entire switching network and the creation of economically and / or technically unfavorable connections systematically prevent. The first assigners can be in all exchanges not only similar but as a memory with not due to regular switching processes changeable memory content, can also be set up very cost-effectively. The changeable ones Information will be on the other hand included in the mentioned second allocator, which accordingly is constructed. By including the connected to the respective exchange Information relating to trunk groups in the second allocator can be these Different from exchange to exchange and newer when the system is created Trunk group or failure of existing trunk group changing information via the trunk group connected to the respective exchange Easily and clearly brought up to date. But are from this one inevitably more complex allocator all those allocation information kept away and put down elsewhere (first assigner) that of their Naturally unchangeable because they are conditioned by the systematics of the network structure.

It is possible to change the category of your own in each exchange Switching center with regard to the origin and / or destination of the connection on the basis of a Determination of a designation of origin and / or on the basis of the respective target of the To determine the connection determining directional code. According to further training the invention, however, it is provided that in the respective exchange Category submitted by the first and second allocator together with the direction code for an occupied line in the selected trunk group to the next exchange reached via this and here the is fed to the first allocator. This makes individual determination unnecessary the category of its own switching center in each of the switching centers. According to a further embodiment of the invention it is provided that the originating exchanges each issue an original identifier that is assigned to the first assigner of the in the course of each connection to be established in the first place switching center is forwarded.

According to a further development of the invention it is provided that the assignment parameters Remaining in the first allocator and variable in the second allocator. Through this the possibility is created when creating new trunk groups in the network and / or in the event of failure of existing trunk groups, the necessary allocations to special easy and clear way to change. The systematics of the network structure The relevant assignments are not affected by these changes; They are in deposited in the first assigners of the switching centers. Changes are only required in the second allocators.

According to a further embodiment of the invention, the first allocators hardwired mappings.

As a result, they can be manufactured in a particularly cost-saving manner.

According to a further embodiment of the invention, the second allocators are designed as a memory, without changing their circuit structure Allow changes to their memory contents. This allows changes in the Switching network that enables the creation of new trunk groups and the failure of existing ones Concerning trunk groups in the network, can be carried out particularly easily and quickly.

According to a further embodiment of the invention, the first allocators The same assignments are made in the various exchanges and are uniform built according to the network hierarchy. This enables series production the first allocator despite filing the assignments in a corresponding assignment wiring.

According to a further embodiment of the invention, the second allocators in the various exchanges depending on the expansion of the hierarchical Switching network and are individually based on the in the respective exchange established traffic relationships given.

As a result, they are different from exchange to exchange Assignments in the second assignments provided exclusively for this purpose drawn together.

In the exemplary embodiment described in detail below a telephone exchange network is presupposed, as it has already been done by »Elektrotechnik und Maschinenbau «, magazine of the Electrotechnical Association of Austria, Springer-Verlag Vienna 1961, S53, Figures 1 and 2, and by the magazine "SEL-Nachrichten" 1961, (9th year), issue 1, p. 28 ff, Fig. 1, is known. F i g. 1 now shows off such a switching network an excerpt, namely three central exchanges 2, 3 and 4, three main switches 32, 33 and 24, four node switches 325,322,333 and 245 and two final exchanges A and C The node exchanges 322 and 325 belong to the main switch section of the main switch 32. Main exchanges 32 and 33 belong to the central office area the central exchange 3. The same applies to the node exchange 245, the main exchange 24 and the central exchange 2.

The telephone switching network is, as in the aforementioned Figure 1 of the SEL messages is shown in a star shape. At the top level of the Central exchanges 2, 3, 4 and others not shown are these by a Mesh network of trunk groups connected by trunk lines. The main exchanges of the respective area of each central exchange are star-shaped with this connected via further trunk groups of trunk lines. The nodal exchanges of the respective area of each main exchange are star-shaped with this connected via further trunk groups. The end exchanges of the respective Area of each nodal exchange are with this in a star shape over further trunk groups connected. Except for this strictly hierarchical star network of trunk groups are the exchanges over deviating from the network hierarchy Cross line bundles connected to each other, which are the star network nodes of the various Mesh network levels with one another.

In Fig. 1 includes the trunk groups B 1, B 16, B25, B33, B52, B71 and B9 to the star network of trunk lines; the remaining trunk groups are cross line bundles.

For a connection from the local exchange A to the local exchange C there are a large number of connection options. There is a majority the long distance exchanges reached in the course of such a connection establishment a choice from several possible routes. For a connection from the local exchange A to the final exchange Exist in the long distance exchanges represented by circles (Central, main and nodal exchanges) each of them Paths, which are indicated by the arrows labeled B 1, B9 to B81.

In Fig. Figure 2 is an arrangement of three allocators Z1, 22 and Z3 and a comparator V shown. This arrangement is part of a central one Control device of a telephone exchange. Furthermore, in FIG. 2 a device R shown, which is both part of this central control device as well as a register that can be connected to this. In the further description it is assumed that the device R is a register.

To establish a long-distance connection, the calling subscriber dialed the number of another subscriber who was sent to another exchange connected than the calling party. Assume a to the local exchange A connected calling party dials one to the local exchange C connected participants. As is well known, the number includes in the first place a so-called traffic elimination number, whereby the calling subscriber from the local exchange receives access to the toll switch. By choosing the Number zero in the first place is the calling subscriber via a line of the trunk group B1 with the long-distance exchange 245 and in this with a free election receiver tied together. As is well known, the number includes the multi-digit number in second place Area code of the local exchange to which the called subscriber is connected is, in the present case, the area code of the local exchange C. The Thirdly, as is known, the call number includes the multi-digit subscriber number of the called party Participant. The subscriber number is used to establish a connection within the Terminal exchange of the called subscriber.

The traffic elimination number in the first place of the phone numbers for Establishing long-distance telephone connections thus serves to reach one of the telephone exchanges and the subscriber number for connection establishment within the local exchange of the called subscriber. The multi-digit area code, on the other hand, is used for control of the relevant long-distance exchanges, which in the course of the establishment of a connection can be achieved one after the other.

For this purpose, this area code is changed from long distance exchange to long distance exchange passed on.

In each of the long-distance exchanges, the area code also becomes briefly referred to only as an "identification number", a target point information is formed. Here several key figures can jointly correspond to target point information, in particular for key figures of remote end exchanges and those within, respectively one and the same node, main and central exchange area.

In Fig. 2, register R is used to record the code number for each Connection establishment. The key figure is passed on to a allocator Z3, in which target point information is derived from it.

The allocator Z3 can, for. B. be trained as it is in German Patent 10 44 901, Fig. 1, left side, shown is the target point information is used as the address for controlling a further allocator 22.

This allocator is a bundle memory that contains information for each destination is able to indicate which trunk line bundle to reach the selected End exchange overall come into question. This allocator 22 contains pro Target information the bundle names concerned; these contains it in a set order, which changes the selection order below the respective trunk line bundles in question when controlling the relevant End switch is set. The allocator is in a manner known per se trained, e.g. B. similar to that in German Patent 19 17 442, in particular Fig. 2 and description is shown. The assigner provides further information, but which will only be explained further below.

It is also possible to save the allocator 23 by changing its function is also taken over by the allocator 22. In this case, the allocator 22 becomes direct controlled with the key figure. One for each of the several terminal exchanges common groups of trunk lines corresponds to a respective one in the allocator 23 Memory area that can be controlled with the various relevant key figures. However, the names of the relevant trunk line bundles can also be used for each code number of the corresponding bundle groups.

In this description of the exemplary embodiment, it is assumed that that in the establishment of long-distance connections between the at the star network nodes and the switching centers located at the star network endpoints, not only those of the network hierarchy corresponding control routes but also bypass routes that deviate from the network hierarchy can be used. These bypass routes can be both shortcuts and Detours via transit exchanges. This prevents a set To exceed the maximum number of detours per connection. For this purpose information over one that has already been partially processed and possibly over one a detour was made to establish a connection under construction to further Transfer of the course of this connection lying remote exchanges. In these Long distance exchanges is to continue establishing the same connection a use of trunk groups leading via further detours through this information restricted.

With those used to establish a connection and accordingly the interconnection progress from toll switch to toll switch forwarded election information (this includes the code, as already explained was) is determined by the in each case in the course of the progressive connection establishment last traversed long distance switching center to the next long distance switching center reached the same related additional information about which network level this last-mentioned telephone exchange belongs and in what relation it belongs Telecommunication center in terms of its position - in terms of the network hierarchy - is related to the origin and / or destination of the connection. In the exchanges each the key figure with the additional information to determine both the for the further connection establishment available star network trunk line bundle and Cross-connection trunk line bundles as well as specifying the respectively applicable selection sequence among these trunk lines to the exclusion of those for further connection setup each non-eligible trunk group linked. From this link This also results in the new additional information for the next to be assigned Toll switch. It is also ensured that the network hierarchy in the Original Jump area in ascending order and connections running through in the target area in descending order Long distance exchanges already reached as transit exchanges only by Long-distance exchanges at the same network level can be reached. As transit exchanges Remote exchanges reached are prevented, further remote exchanges as transit exchanges. Count as transit exchanges such toll exchanges, which are related to the origin and destination of a respective Connection represent a detour for the connection through-connection.

In the present example according to FIG. is the central exchange 4 a transit switch for a connection between one to the final switch A and a subscriber connected to the local exchange C, if this Connection through central offices 2, 4 and 3 runs.

On the basis of the respective origin and / or destination a connection ascertainable relation of each of the exchanges with respect to every connection to be switched through, defined by origin and destination and with regard to At their own network level, these switching centers are in different categories divided. A category does not simply apply to an exchange but always only in relation to the connection to be switched through; in fact in relation to their origin and destination and in relation to the respective network level Exchange. These categories are as follows (the abbreviations are in brackets of these categories): a) Node, main or central exchange, which is reached directly by the terminal exchange of the calling subscriber became (UE). End exchanges can also be used at node exchanges (as shown in FIG. 1) also directly to main exchanges and central exchanges be connected, b) main exchange in the area of origin (UH). The person in question The terminal exchange of the calling subscriber thus belongs to the main exchange area the main exchange concerned.

c) Central exchange in the area of origin (UZ). The final exchange of the calling subscriber belongs to the central exchange area of the relevant Central exchange.

d) Transit Switching Center (TR). Neither the local exchange of the calling subscriber or the terminal exchange of the called subscriber lies in the area of the relevant node, main or central exchange. There are therefore transit exchanges in all three trunk network levels.

e) Transit switching center in a lower network level than the main or central exchange to which the end exchange of the calling subscriber (special case) is directly connected (TU). This acts So it is the special case that the terminal exchange of the calling subscriber is directly connected to a main or central exchange and the Transit exchange reached remote exchange towards this main or central switching center is in a lower network level.

f) Node exchange, within its range the Terminal exchange of the selected subscriber is (ZK).

g) Main exchange, in whose area the end exchange of the selected subscriber is (ZH).

h) Central exchange, in whose area the final exchange of the selected subscriber is (ZZ).

i) Terminal exchange (ZE).

The exchanges are therefore not simply in these categories divided, but always with regard to the connection to be switched through and with regard to their origin and destination (final exchange of the calling Subscriber and terminal exchange of the called subscriber). These categories also indicate the respective network level.

In each of the long-distance exchanges is now in below described in detail in each case the category of that switching center determined which of the selected for further connection establishment Trunk group is reached.

This category is used along with the key number of the local exchange of the selected subscriber to the next remote switch to be reached transfer. The terminating exchange of the calling subscriber will consequently always transfer the category UE.

In each of the long distance exchanges, the code is displayed along with the category in register R in FIG. 2 received. To determine the further way for the connection throughput, the code is in the already described Way supplied to the allocator 23, which in turn sends destination information to the Allocator 22 transfers. However, the category (K) is transferred from register R to a mapper Z1 transferred.

This assigner thus receives the category of its own exchange and indicates on the output side the categories of such switching centers that are outgoing on the category of your own exchange with regard to the structure of the Network hierarchy are generally permitted for further connection establishment. The allocators Z1 in the various exchanges have the same allocations and are structured uniformly according to the network hierarchy. The assignments are Permanently stored, preferably through permanent wiring.

A »second allocator« is also provided in the exchanges, which in the present case consists of the assigners 22 and 23 already mentioned.

On the basis of the received code number, the allocator 22 is after a target-related selection sequence ordered names of all to achieve the selected destination from the existing and planned trunk group. These designations are individually the respective categories of those to be reached via this trunk group Switching offices attached. With the help of a comparator arrangement is under the trunk groups designated by the allocator 22 according to the target-related selection sequence one is selected that has both at least one free line and one which corresponds to the categories marked as permissible on the output side by the allocator Zt.

When progressing from toll switch to toll switch Connection through-connection is always a route identifier together with the code transfer. This contains, among other things, the category of in the course of the long distance switching center progressing to toll switch Reached connection establishment next Toll switch. The category is consequently in the course of one over several toll switches to be switched through and accordingly consisting of several connection sections Remote connection from connection section to connection section always a different one.

In the event that the terminal exchange of the selected subscriber is in the area of the same main exchange or node exchange like the terminating exchange of the calling party, it is prevented that the higher-level central exchange or main exchange can be reached can. That would be pointless. For this purpose, the allocator 22 gives a corresponding target-dependent first blocking notice. In a manner not explained in detail, the bundle selection prevented that the relevant central exchange or main exchange can be reached.

In the event that a central or main exchange is reached was, and the further paths from there to the terminal exchange of the selected If the participant was found not to be free, the connection will be closed the upstream remote switching center in the course of the remote connection being established triggered again with the return of a return tax indicator. In this upstream The long-distance exchange is the connection establishment according to the target-related selection sequence continued through another bundle of trunk lines. So now with unsuccessful activation of a main exchange or a central exchange, in whose area the selected terminal exchange is located, this main exchange or central exchange cannot be controlled again, gives the Allocator 22 together with the bundle name, the category and what has already been mentioned first blocking note except for a reversal for the busy case in the following reached remote switching center preparatory identifier a second blocking notice from which the blocking of the main exchange or the central exchange, in the area of which the selected end-of-line exchange is located (SH, SZ). This The second blocking notice is initially stored in the register in the same exchange. In the case of reverse reversal, this blocking signal is used when a line is occupied of a further bundle in the route identifier transmitted together with the code inserted. This second blocking notice is transferred from exchange to exchange forwarded with the route identifier.

So when selecting a bundle in a toll switch, won a bundle name, among other things. This is the setting devices, not shown fed. If a free line is found in the bundle concerned, then the connection is switched through this to the next long-distance exchange. to this is transmitted with the code number, the route identifier. Will, however, in that If no free line has been found in the relevant bundle, the allocator 22 turns on Using the same target point information, the next bundle is determined. Here again ensured by means of the comparator that only one to such a long distance exchange leading bundle is selected, which is one of those marked as permissible by allocator Z1 Category corresponds. - Notwithstanding this, it is also possible immediately to take into account the busy status of trunk groups when selecting a bundle. As a result, multiple use of the assigner 22 is avoided by at the same time a trunk group is selected according to the categories specified by the allocator Z1 permissible and intended to achieve the selected goal, and at least that still contains a free line.

If the route identifier is now used together with the code from a long-distance exchange transmitted to the nearest toll switch. so is used by the receiving register the identification number to the allocator 23 and from this a destination point information to the allocator 22, on the other hand the category possibly together with a second blocking notice forwarded to allocator Z1.

In Fig. 3 are the assignments between the in a toll switch received categories (column under K) together with blocking notes (columns under SZ, SH) and the relevant categories in this telephone exchange for the bundle selection (Columns under ZE to UZ) shown in a table. The assignments are in Allocator Z1 is stored in each of the trunk exchanges. Each in two capital letters Abbreviations given in the table were explained above. they give the category. A 1 or O in the columns of the blocking notes SZ and / or SH means that these blocking flags were received or not, and accordingly as Input data are used for the allocator Z1 in addition to the category received in each case. The ones and zeros in the columns of the categories indicate which categories are admissible or not in the case in question.

In Fig. 4 are the associations between the destination information and the cable bundles provided for each destination point. These assignments are stored in allocator 22. The in F i g. 4 represent the assignments shown represent only a small excerpt. They all apply to reaching the local exchange C in Fig. 1 from the terminal exchange A, namely for all in F i G. 1 illustrated long distance exchanges. A total of 10 columns are shown. Above each column it is underlined which of the Fernvermittlungsstellcn the specified column is saved. The columns indicated in Fig. 4 are therefore stored in ten different telephone exchanges.

In each of the columns the bundles are now indicated one below the other, which to achieve the in the head of each respective column specified long distance or local exchange are available in total. As can be seen, the bundle names are identical with the names of the telephone exchanges directly reached through them. The order in which they are listed below each other determines the order in which they are selected after which they are available for the bundle selection. To the right of everyone Bundle name is the category of the directly reached via the bundle in question Toll switch. This category is for the same long-distance exchanges different of course; and it is determined by the relation the relevant long-distance switching center to the origin and destination of the respective Link. Furthermore, the category of the respective toll switch is through determines their own network level.

To select a bundle, the destination information is used in the allocator 22 the relevant memory section is controlled as the memory address. When controlling the Terminal exchange C is thus in each case in one of the long-distance exchanges indicated in FIG that memory part of the allocator Z2 is activated which contains the in FIG. 4 specified Memory content carries.

From the bundle names arranged in the specified selection sequence the first is selected, the associated category of which is considered permissible by the assigner Zl is specified. When making this selection, it is possible to also take into account whether the line bundle in question still has at least one free line. as well but it is also possible to initially ignore this criterion and to attempt a connection throughput with the selected trunk group name company and if all lines of the controlled line bundle are occupied again to interrogate the assigners Zl and 22 and found those already occupied Exclude trunk groups from the further selection process from the outset.

At the top of each column in FIG. 4 is also a destination identifier specified. It contains the first blocking notes EZ or EH, a note RU or

GB for whether a lane busy signal when all connection options are busy (for GB) or a return control code (for RU) is to be returned; in the destination identifier may also contain a second blocking notice (SH or SZ), which has already been explained above.

Claims (8)

Claims: 1. Method for routing in telecommunications exchanges, in particular telephone exchanges, in one in several superimposed on each other Hierarchically structured telecommunications switching network, in particular Telephone switching network consisting of a star network corresponding to the network hierarchy of trunk groups, from a mesh network of trunk groups in a top one Network level and, if necessary, the star network nodes that deviate from the network hierarchy of the various network levels intermeshing cross-line bundles is, that it is not indicated that due to the with regard to the respective origin and / or destination of a connection ascertainable relation each of the switching centers with regard to each to be switched through, by origin and destination defined connection and these switching centers with regard to their own network level are divided into different categories, that in the exchanges a first Assigners an input for the category of their own exchange and a Has output for the categories of such exchanges starting from the category of its own exchange with regard to the structure of the network hierarchy for further connection establishment are generally permitted that in the exchanges a second assigner has an input for which the respective destination of a connection is determined Direction code and an exit for according to a target-related selection sequence Ordered names of all and provided cable bundle that these designations individually the respective Categories of the exchanges that can be reached via this trunk group are attached are. and that among these trunk groups according to the target-related selection order one is selected that has at least one free line as well one of the categories marked as permissible on the output side by the first assigner is equivalent to. 2. The method according to claim 1, characterized in that the in of the respective exchange from the first and second allocators given categories together with the direction code via an occupied line of the selected trunk group to the next exchange reached via this and is fed to the first allocator here. - 3. The method according to claim 2, characterized in that the originating exchanges each have an origin identifier submit that to the first assigner of the connection to be established in each case is routed to the first switching center. 4. The method according to claim 1, characterized in that the assignments Remaining in the first allocator and variable in the second allocator. 5. The method according to claim 4, characterized in that the first Assigners have hardwired mappings. 6. The method according to claim 4, characterized draws that the second Allocators are memories that make changes without changing their circuit structure of their memory content. 7. The method according to claim 1, characterized in that the first Allocators in the various exchanges have the same assignments and are structured uniformly according to the network hierarchy. 8. The method according to claim 1, characterized in that the second Allocators in the various exchanges depending on the expansion of the hierarchical Switching network have different assignments and individually according to the in the respective exchange given traffic relationships are established. Method for routing in telecommunications exchanges, in particular Telephone exchanges in one of several superimposed network levels structured, hierarchically ordered telecommunications switching network, in particular telephone switching network, that from a star network of trunk groups corresponding to the network hierarchy a mesh network of trunk groups in a top network level and possibly from deviating from the network hierarchy, the star network nodes of the various Network levels intermeshing cross-line bundles is built. A method of this type is already through the DT-AS ii 48 602, Fig. 1, known. Through this interpretation it is also known to use compounds except via a regular route, which is also used as a key figure route in the German state remote election and via cross paths - these enable abbreviations of the respectively to be switched through Connection - to be switched through via detours and transit exchanges. In Telecommunication networks of the type required at the beginning therefore have the option of to establish the connections in each case in different ways. it is also known by the aforementioned interpretation, the variety to restrict the switching options for the individual connections in order to a through-connection of uneconomical connections (too long detours) and / or technically unusable connections (too many line sections in a row in one connection, too high attenuation values, instability of four-wire connections) to prevent. The explained variety of path options and one caused by it You can now choose from among these within the relevant exchange the knowledge of both the ones to be considered for the respectively selected destination Trunk group as well as the option of selecting a trunk group under Consideration on the one hand of possible bundle busy states and on the other hand a selection sequence predetermined by the question of economic viability. This knowledge therefore relates to information other than the previously mentioned information Information on the structure of the telecommunications network.