DE4329576A1 - Exchange to perform call transfer and/or call diversion - Google Patents

Abstract

A versatile and flexible use of the "call transfer" and "call diversion" service features is described which enables switched connections in a communications network. According to the invention, at least one connection line section counter (ZA1, ZA2, ..., ZG1, ZG2) is implemented for this purpose in an exchange (Vst1, ..., Vst6) which counts the seizures of connection line sections (VL1, ..., VL7) connected to this exchange (Vst1, ..., Vst6) when the two service features are performed and/or counts the number of connection line sections (VL1, ..., VL7) which are interconnected when the "call transfer" service feature is performed. The two service features can be performed a number of times. When a number stored in a storage means (VL MAX1, ..., VL MAX6) is reached or exceeded, no further performances of the service features are permitted. <IMAGE>

Description

The present invention relates to a switching center according to the preamble of claim 1.

In the trade journal ntz, vol. 35 (1982), issue 8, page 554 the known service features queries, transfer of a call and Call forwarding described. If a participant is in one Have a conversation with another subscriber in the news network he by means of the "Queries" feature the possibility from the existing conversation, a consultation call with one to lead other participants without talking to the other Trigger participants. This conversation is taking place during the Consultation call on hold.

Using the "Transfer a call" feature, the Now the participant is on hold with the other participants with their own separation from the others Hand over participants.

Incoming calls can be made using the "Call forwarding" feature Conversation requests from the participant to a predetermined, be diverted to other participants.

It is the object of the present invention to be a revealing and flexible use of a service feature "transfer of a call" and / or "call forwarding".

According to the invention, this object is achieved through the technical teaching of Claim 1 solved.

Further advantageous embodiments of the invention are the dependent patent claims.

For a better understanding of the invention, the following exemplary embodiments are described with reference to FIGS. 1 to 3. Show it:

Fig. 1 shows an embodiment of a communication network having a number of switching centers according to the invention,

Fig. 2 shows an embodiment of a timing of a simple implementation of the service features "transfer a call" and "call forwarding" in the message network of Fig. 1 and

Fig. 3 shows an embodiment of a time sequence of a multiple execution of the supplementary services "Transferring a call" and "call forwarding" in the communications network of FIG. 1.

In the three embodiments, the same or elements with the same effect are given the same reference symbols throughout used.

The embodiment shown in FIG. 1 shows a message network N with a number of six switching centers Vst1,. . . , Vst6, which have a number of seven connecting line sections VL1,. . . , VL7 are connected to each other.

Vst1 is above the first VL1 and second VL2 Connecting line section with Vst2 and Vst2 in turn over the third VL3 and fourth VL4 connecting line section with Vst3 connected. Vst2 is still over the fifth Connection line section VL5 connected to Vst4. Vst4 is over the sixth connecting line section VL6 to Vst5 and Vst5 continue via the seventh connecting line section VL7 to Vst6 connected. A number of seven participants A,. . . , G is each by means of a subscriber line TA1,. . . , TA7 and one Subscriber line TL1,. . . , TL7 to one of the Switching centers Vst1,. . . , Vst6 in the following way connected: TlnA using TA1 and TL1 to Vst3, T1nB using TA2 and TL2 on Vst2, T1nC using TA3 and TL3 on Vst1, T1nD using TA4 and TL4 also on Vst2, T1nE using TA5 and TL5 on Vst4, T1nF using TA6 and TL6 on Vst5 and T1nG using TA7 and TL7 on Vst6.

For each of the participants A,. . . , G is in the exchange, to which it is connected, a first ZA1,. . . , ZG1 and a second ZA2,. . . , ZG2 trunk section counter furnished.

In the present exemplary embodiment, the message network N is a private, digital integrated service message network (ISDN) with signaling according to the GCITT signaling system No. 7. It has a connection to a public message network, not shown in the figure. In addition to the six switching centers Vst1,. . . , Vst6 may also be present in the message network N, further switching centers, not shown in FIG. 1, which are connected to one another and to the six switching centers Vst1,. . . , Vst6 are connected. Since the invention only relates to switching centers which are an originating or a destination switching center when carrying out the two service features "transferring a call" and "call forwarding", the further switching centers do not play a role in clarifying the invention. They are transit exchanges.

Hence are only required for the representation of the invention, connecting line VL1 portions in FIGS. 1. . . , VL7 with the associated origin and destination switching centers Vst1,. . . , Vst6 shown.

An IAM is required to carry out the method according to the invention (Initial Address Message) - and a FIN (Facility Information) - CCITT Signaling System # 7 signaling information by one VLZ parameter to expand the corresponding counter value Trunk section counter ZA1, ZA2,. . . , ZG1, ZG2 one the participant A,. . . , G indicates.

Each trunk section counter ZA1, ZA2,. . . , ZG1, ZG2 counts the number of connecting line sections for one Connection between the participant to whom the respective Connection line section counter ZA1, ZA2,. . . , ZG1, ZG2 is assigned, and one of the other participants of the Communication network N have been occupied, and the number of already occupied connecting line sections, which when using the Service feature "transfer a call" can be connected.

In each of the switching centers Vst1,. . . , Vst6 is a Storage means VL MAX1,. . . , VL MAX6 that integrates a number contains the maximum count value in each Exchange Vst1,. . . , Vst6 decorated Connection line section counter ZA1, ZA2,. . . , ZG1, ZG2 specifies. This number can be based on several different criteria be determined. For example, the definition in Dependence on the current load of the News network or depending on the time of day.  

FIG. 2 shows the exemplary embodiment in which the time sequence of the simple implementation of the two service features "transfer of a call" and "call diversion" in the message network N according to FIG. 1 is shown schematically. A connection setup from subscriber A to subscriber D is described in three steps. In the first step, subscriber A calls subscriber B via connection line section VL3. This connection setup from subscriber A to subscriber B is signaled by means of a first IAM 1 signaling information via an associated signaling channel. On the basis of the assignment of VL3, the first connecting line section counter ZA1 assigned to subscriber A is increased to the count "one" in the switching center Vst3. The first IAM₁ signaling information contains the count of ZA1, which is to be transmitted to the switching center Vst2 to which the subscriber B is connected. The transmission of the count value of one of the connecting line section counters ZA1, ZA2,. . . , ZG1, ZG2 by one of the IAM or FIN signaling information is indicated in FIG. 2 and FIG. 3 by the bracketed expression attached to the IAM or FIN signaling information, which corresponds to the parameter VLZ. The count of the first trunk section counter ZB1 assigned to subscriber B is also increased to "one". In the second step, subscriber B carries out a "query" to subscriber C via connecting line section VL1. This connection establishment from subscriber B to subscriber C is signaled as above by means of a second IAM₂ signaling information. The second connecting line section counter ZB2 assigned to user B and the first connecting line section counter ZC1 assigned to user C are each increased to the count value "one". Since the subscriber C has switched "call forwarding" to the subscriber D, the "consultation" of the subscriber B is redirected to the subscriber D via the connecting line section VL2. The "call forwarding" is the switching center Vst2, to which the subscriber B is connected, signaled backwards via an associated signaling channel by means of a first FIN₁ signaling information. Upon receipt of the first FIN 1 signaling information indicating "call forwarding" in the exchange Vst2, the connecting line section counter ZB2 is increased to the count "two". The count value of ZC1 remains "one". For the establishment of connection from subscriber C to subscriber D, a third IAM₃ signaling information is sent from Vst1 to Vst2 via the corresponding signaling channel. This third IAM₃ signaling information contains the count of the assigned to the subscriber C, second trunk section counter ZC2, which is increased due to the occupied for the "call forwarding" second - besides VL1 - trunk section VL2 to the count "two". With the receipt of the third IAM₃ signaling information in the Vst2, the subscriber D assigned to the first trunk section counter ZD1 is set to the count "two". In the third step, subscriber B initiates the "transfer of a call" service feature from the inquiry call by interconnecting the connection on hold to subscriber A and the active connection to subscriber D while disconnecting himself. The two connecting line section counters ZB1 and ZB2 assigned to the transferring subscriber B are transmitted in the following manner to the switching centers Vst3 and Vst2 of the two end subscribers A and D of the connection which now exists. The count of the connecting line section counter ZB1, which characterizes the held connection from subscriber A to subscriber B, is by means of a third FIN 3 signaling information, which signals the "transfer of a call" by subscriber B, from Vst2 via Vst1 to which the forwarding subscriber C connected, transferred back to Vst2. There, the count of the first connecting line section counter ZD1 assigned to subscriber D increases to "three". The count value of the connecting line section counter ZB2, which characterizes the inquiry connection of the subscriber B to the subscriber D, is transmitted from Vst2 to Vst3 by means of a second FIN₂ signaling information which also signals the "transfer of a call" by the subscriber B. There, the count of the first connecting line section counter ZA1 assigned to subscriber A thus increases to "three". The currently existing connection between two of the participants A,. . . , G can be recognized in each case by the same count value of the corresponding connecting line section counters ZA1, ZA2, ZG1, ZG2.

In the present second embodiment there is after 3rd step the connection between subscriber A and the Subscriber D. The associated trunk section counters ZA1 and ZD1 both have the count "three". So that's the Exchange Vst3 and Vst2 the occupied number of Connection line sections known for this connection and can with further call actions from or to the participants A or D are evaluated.

FIG. 3 shows the exemplary embodiment in which the time sequence of the multiple execution of the two service features "transfer of a call" and "call diversion" in the message network N according to FIG. 1 is shown schematically. A connection setup initiated by subscriber A is described in six steps, which leads to an active connection between subscriber C and subscriber F and a connection which is on hold between subscriber F and subscriber G. In the first step, subscriber A calls subscriber B via connecting line section VL3. This connection establishment from subscriber A to subscriber B is signaled by means of a fourth IAM signaling information via an associated signaling channel. On the basis of the assignment of VL3, the first connecting line section counter ZA1 assigned to subscriber A is increased to the count "one" in the switching center Vst3. The fourth IAM₄ signaling information contains the count value of ZA1, which is transmitted to the switching center Vst2 to which subscriber B is connected. The count value of the first connecting line section counter ZB1 assigned to subscriber B is also increased to "one". Since subscriber B has switched "call forwarding" to subscriber C, subscriber A's call is forwarded to subscriber C via connecting line section VL1. The "call forwarding" is signaled to the switching center Vst3 to which subscriber A is connected backwards via an associated signaling channel by means of a fourth FIN₄ signaling information. Upon receipt of the fourth VIN3 signaling information indicating "call forwarding" in Vst3, the connection line counter ZA1 is increased to the count "two". The count value of ZB1 remains "one". A fifth IAM₅ signaling information is sent from Vst2 to Vst1 via the corresponding signaling channel for establishing the connection from subscriber B to subscriber C. This fifth IAM₅ signaling information contains the count of the second trunk section counter ZB2 assigned to subscriber B, which is increased to the count "two" due to the second - besides VL3 - trunk section VL1 used for "call forwarding". When the fifth IAM fünf signaling information is received, the first connecting line section counter ZC1 assigned to the subscriber C is set to the count value "two". In the second step, subscriber A carries out a "query" to subscriber D via connecting line section VL4. This connection establishment from subscriber A to subscriber D is signaled by means of a sixth IAM signaling information. The second connecting line section counter ZA2 assigned to user A and the first connecting line counter ZD1 assigned to user D are each increased to the count value "one". However, since subscriber D has also switched "call forwarding" to subscriber E, "inquiry" from subscriber A is forwarded to subscriber E via connecting line section VL5. The "call forwarding" is signaled to the switching center Vst3, to which subscriber A is connected, backwards via an associated signaling channel by means of a fifth VIN signaling information. Upon receipt of the fifth FIN₅ signaling information indicating "call forwarding" in the switching center Vst3, the connecting line section counter ZA2 is increased to the count "two". The count of ZD1 remains "one". For the establishment of the connection from subscriber D to subscriber E, a seventh IAM signaling information is sent from Vst2 to Vst4 via the corresponding signaling channel. This seventh IAM₇ signaling information contains the count value of the second trunk section counter ZD2 assigned to subscriber D, which is increased to the count value "two" due to the second - besides VL4 - trunk section VL5 occupied for "call forwarding". With the receipt of the seventh IAM Zeichen signaling information in the Vst4, the first connecting line section counter ZE1 assigned to the subscriber E is set to the count value "two". In the third step, subscriber A initiates the "transfer of a call" service feature from the inquiry call by interconnecting the connection on hold to subscriber C and the active connection to subscriber E while disconnecting himself. The two connection line section counters ZA1 and ZA2 assigned to subscriber A are made known to the exchanges Vst1 and Vst4 of the two end subscribers c and E of the connection now existing in the following manner. The count value of the connecting line section counter ZA1, which characterizes the held connection from subscriber A to subscriber C, is transmitted from Vst3 to Vst4 by means of a seventh FIN₇ signaling information which signals the "transfer of a call" by subscriber A. There, the count value of the first connecting line section counter ZE1 assigned to the subscriber E increases to "four". The count value of the connecting line section counter ZA2, which characterizes the inquiry connection of subscriber A to subscriber E, is transmitted from Vst3 to Vst1 by means of a sixth FIN₆ signaling information, which also signals the "transfer of a call" by subscriber A. There, the count value of the first connecting line section counter ZC1 assigned to subscriber C increases to "four". In the fourth step, the subscriber G calls the subscriber F via the connecting line section VL7. This connection establishment from subscriber G to subscriber F is signaled by means of an eighth IAM₈ signaling information via an associated signaling channel. On the basis of the assignment of VL7, the first connecting line section counter ZG1 assigned to the subscriber G is increased to the count "one" in the switching center Vst6. The eighth IAM₈ signaling information contains the count value of ZG1, which the Vst5 to which the subscriber F is to be made known. The count value of the first connecting line section counter ZF1 assigned to the subscriber F is also increased to "one". In the fifth step, subscriber F carries out an inquiry via subscriber line section VL6 to subscriber E, who puts his active connection to subscriber C on hold and accepts the "inquiry" from subscriber F indicated by a "call waiting" service feature. This connection establishment from subscriber F to subscriber E is signaled by means of a ninth IAM signaling information. The second connecting line section counter ZF2 assigned to the subscriber F and the second connecting line section counter ZE2 assigned to the subscriber E are each increased to the count value "one". In the sixth step, subscriber E initiates the "transfer of a call" service feature from the inquiry connection with subscriber F by interconnecting the connection on hold to subscriber C and the active connection to subscriber F while disconnecting himself. The two connecting line section counters ZE1 and ZE2 assigned to the subscriber E are made known to the exchanges Vst1 and Vst5 of the two end subscribers C and F of the connection which now exists in the following manner. The count value of the connection line section counter ZE1, which characterizes the held connection from the subscriber C to the subscriber E, is transmitted from the Vst4 to the Vst5 by means of a ninth FIN₉ signaling information which signals the "transfer of a call" by the subscriber E. There the count value of the second connecting line section counter ZF2 assigned to the subscriber F increases to "five". The count value of the connection line section counter ZE2, which characterizes the inquiry connection of the subscriber E to the subscriber F, is transmitted from Vst4 to Vst1 by means of an eighth FIN₈ signaling information which also signals the "transfer of a call" by the subscriber E. There the count value of the first connecting line section counter ZC1 assigned to the subscriber C increases to "five". The count values of the connecting line section counters ZF1 and ZG1 of the held connection from subscriber G to subscriber F remain unchanged. In the present third exemplary embodiment, after the sixth step, there is once the active connection between the subscribers C and F and secondly the connection between the subscribers G and F which is in the hold state.

As the exemplary embodiments show, the count values of Connection line section counter ZA1, ZA2,. . . , ZG1, ZG2 in one Transit exchange not increased.  

The link section counters ZC1 and ZF2 have in the last Embodiment reached the count "five". Would at the repeated execution of the "transfer of a call" and the "Call forwarding" and the associated increase in Connection line section counter ZA1, ZA2,. . . , ZG1, ZG2 the Count value of at least one of the trunk section counters ZA1, ZA2,. . . , ZG1, ZG2 reach the number in the Storage means VL MAX1,. . . or VL MAX6 of the exchange is stored in which this is at least one Connection line section counter ZA1, ZA2,. . . , ZG1, ZG2 then the intended re - implementation of the "Transfer a call" and "Call forwarding" were not carried out. The existing connection would be released. In the third Exemplary embodiment would be the "flipping a Call "no longer carried out by subscriber E if one the storage means VL MAX1 or VL MAX5 the number "five" would have saved. The connections from subscriber E to the Participants C and F would be triggered.

The implementation of "transferring a call" and the "Call forwarding" can also be implemented so that only at Exceeding the in one of the storage means VL MAX1,. . . , VL MAX6 stored number did not run again would.

The implementation of "transferring a call" and the "Call forwarding" can be used for participants with a digital as well as with an analog subscriber connection for connecting any connecting lines and / or Subscriber lines take place. However, it makes sense limit the implementation to a one-off implementation, if the IAM and FIN signaling information is via an analog Connection line are transmitted because the counter values of the Subscriber line section counters assigned to subscribers by means of of the IAM and FIN signaling information is no longer signaled can be.  

To further increase the network security, it is possible to the implementation of the "call forwarding" feature restrict, for example, to a one-time implementation. For this purpose, in each of the switching centers Vst1,. . . , Vst2 a third connecting line section counter ZAU,. . . , ZGU implemented, the count of which upon receipt of the the FIN signaling information indicating "call forwarding" increased becomes. In the storage means VL MAX1,. . . , VL MAX6 is another Number stored when reached by the count value of third connecting line section counter ZAU,. . . , ZGU can "Call forwarding" is not permitted again. Furthermore, in at least one of the switching centers Vst1, Vst6 a local redirection counter can be implemented for each implementation of a local "call forwarding" within this exchange is increased. Is one specific to this Switch set maximum value of this local Forwarding counter reached, no further "call forwarding" be performed.

Claims (3)

1. Switching center (Vst1,..., Vst6) in a communications network (N) for switched connections for carrying out a transfer of a call and / or a call forwarding, with at least one subscriber line (TA1,..., TA7), via which a Subscriber (A, G) is connected, characterized in that the switching center (Vst1,..., Vst6) has at least one connecting line section counter (ZA1, ZA2, ZG1, ZG2) for the subscriber (A,..., G), the count of which is increased when a connecting line section (VL1,..., VL7) is used to set up a connection between the subscriber (A,..., G) and another subscriber of the communications network (N), the switching center (Vst1, .., Vst6) is either an originating or a destination exchange, and / or its count is also increased when the call diversion is carried out by the other subscriber if the subscriber (A,..., G) is a calling subscriber , and / or its count value continues when a number of connecting line sections (VL1,. . . , VL7) for transferring a call is increased if the subscriber (A,..., G) is an end subscriber of the connection existing after the transfer of a call and that the exchange (Vst1,..., Vst6) has a storage means ( VL MAX1,..., VL MAX6), in which a definable number is stored, when it is reached or exceeded by the count value of the at least one connecting line section counter (ZA1, ZA2,..., ZG1, ZG2) to carry out a transfer Call or call forwarding is not allowed. 2. Switch according to claim 1, characterized in that they two for the participant (A,..., G) Trunk section counter (ZA1, ZA2,..., ZG1, ZG2). 3. Exchange according to claim 1 or 2, characterized characterized that they have a for the participant (A,.., G) has another connecting line section counter (ZAU,..., ZGU), whose count when the call is diverted by the other subscriber is increased, and that in the storage means (VL MAX1,..., VL MAX6) another number is stored at their reaching or exceeding by the counter value of the other Trunk section counter (ZAU,..., ZGU) the Call forwarding is not permitted.