WO2000011882A1 - Signalling in a telecommunications system - Google Patents
Signalling in a telecommunications system Download PDFInfo
- Publication number
- WO2000011882A1 WO2000011882A1 PCT/EP1999/006168 EP9906168W WO0011882A1 WO 2000011882 A1 WO2000011882 A1 WO 2000011882A1 EP 9906168 W EP9906168 W EP 9906168W WO 0011882 A1 WO0011882 A1 WO 0011882A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- signalling
- network
- dssl
- call
- protocol
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M7/00—Arrangements for interconnection between switching centres
- H04M7/12—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal
- H04M7/1205—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal where the types of switching equipement comprises PSTN/ISDN equipment and switching equipment of networks other than PSTN/ISDN, e.g. Internet Protocol networks
- H04M7/1245—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal where the types of switching equipement comprises PSTN/ISDN equipment and switching equipment of networks other than PSTN/ISDN, e.g. Internet Protocol networks where a network other than PSTN/ISDN interconnects two PSTN/ISDN networks
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M7/00—Arrangements for interconnection between switching centres
- H04M7/12—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal
- H04M7/1205—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal where the types of switching equipement comprises PSTN/ISDN equipment and switching equipment of networks other than PSTN/ISDN, e.g. Internet Protocol networks
- H04M7/126—Interworking of session control protocols
- H04M7/1265—Interworking of session control protocols where the session control protocols comprise H.323 and SS7
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/04—Selecting arrangements for multiplex systems for time-division multiplexing
- H04Q11/0428—Integrated services digital network, i.e. systems for transmission of different types of digitised signals, e.g. speech, data, telecentral, television signals
- H04Q11/0435—Details
- H04Q11/0457—Connection protocols
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q3/00—Selecting arrangements
- H04Q3/0016—Arrangements providing connection between exchanges
- H04Q3/0025—Provisions for signalling
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13034—A/D conversion, code compression/expansion
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/1313—Metering, billing
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13174—Data transmission, file transfer
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13176—Common channel signaling, CCS7
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13196—Connection circuit/link/trunk/junction, bridge, router, gateway
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13204—Protocols
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13209—ISDN
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/1322—PBX
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13337—Picturephone, videotelephony
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13389—LAN, internet
Definitions
- the present invention relates to signalling in a telecommunications system and in particular, though not necessarily, to the transmission of signalling data over an H.323 network.
- PSTNs Public Switched Telephone Networks
- NUP Network User Service
- ISDN Integrated Services Digital Network
- DSS1 Digital Subscriber Signalling System No .1
- ISUP ISDN User Part
- a call connection may pass through one or more PSTN parts and one or more ISDN parts.
- Conventional telecommunication networks are designed such that the calling party (A-subscriber, A-user, A- party, A-number, A-address etc.) is normally responsible and therefore charged for the cost of a call and/or connection time, while the called party (B-subscriber, B-user, B-party, B-number, B-address etc.) does not have to pay anything for the received calls and/or the connection time of the received call .
- the charging may be arranged to occur beforehand (so called pre-paid calling arrangements) or afterwards (e.g. by means of a telephone bill) .
- Telephone calls are usually charged according to their duration. Other charging criteria may be used by network operators such as the distance between the subscribers, etc. So as to enable reliable charging, an ongoing call is monitored and required charging information sent to a Call Charging Point (CCP) of the calling party which may be implemented for example in the A-subscriber' s local exchange. So-called pulse metering and toll-ticketing (TT) are referred to herein as possibilities for implementing the charging.
- CCP Call Charging Point
- TT toll-ticketing
- H.323 the International Telecommunications Union
- H.323 Version 2 A fundamental and essential component of H.323 is the provision for the transmission of digitised and compressed voice data.
- H.323 also makes optional provision for the transmission of video and other data forms.
- H.323 has already been implemented in multimedia products such as Microsoft NetmeetingTM.
- a typical scenario might involve a calling party and a called part both being connected to respective PSTN access networks (using for example NUP or TUP) , with part of the intermediate signalling link being provided by an ISDN network (using ISUP) and a part being provided by an H.323 network.
- PSTN access networks using for example NUP or TUP
- ISDN network using ISUP
- H.323 network a typical scenario might involve a calling party and a called part both being connected to respective PSTN access networks (using for example NUP or TUP) , with part of the intermediate signalling link being provided by an ISDN network (using ISUP) and a part being provided by an H.323 network.
- H.323 makes mandatory the use of the ITU standard H.225 which is based on DSS1 (sometimes referred to as Q.931) signalling for the negotiation of a call set-up between two H.323 nodes, to establish a channel therebetween over which the terminals may send user and signalling data.
- DSS1 is mandatory for certain call maintenance and termination functions.
- the inventors of the present invention have discovered that the existing DSS1 based signalling protocol employed by H.323 is not able to accommodate certain signalling information which may be generated within a telecommunications system and for which provision is made in the existing PSTN and ISUP standards. It has further been recognised that this incompatibility hinders the introduction of H.323 in telecommunications networks .
- a calling party In current PSTN networks (where the connection between the calling party and called party is purely PSTN) a calling party (A-subscriber) terminates a call by hanging-up his telephone, i.e. by going "on-hook” . This results in a Clear-Forward Signal (CFS) being sent from the A-subscriber ' s local PSTN exchange to the appropriate Call Charging Point (CCP) . The call is terminated immediately and charge accumulation stopped.
- CCP Call Charging Point
- the mechanism for terminating a call in response to an on-hook by a called party B-subscriber is however somewhat different. On-hook by the B-subscriber is detected at his local PSTN exchange. Detection of a B- subscriber on-hook is signalled back to the CCP by sending a Clear Back (CLB) signal from the B-subsciber ' s local exchange to the CCP.
- CCP Call Charging Point
- Receipt of a CLB signal at the CCP does not immediately result in the termination of the call. Rather, receipt causes the initiation of a timer at the CCP.
- the B-subscriber goes "off-hook" before the expiry of the timer (typically the timer runs for 90 seconds or thereabouts)
- the B-subscriber ' s local exchange sends an REANSWER signal to the CCP. This causes the cancellation of the timer at the CCP. If no REANSWER signal is received by the CCP before expiry of the timer, the CCP causes the connection to be cleared and charge accumulation is stopped. This facility is provided to allow, for example, the B-subscriber to on- hook on one extension and to subsequently off-hook on another extension without terminating the call.
- the CLB and REANSWER signals are carried by appropriate ISUP messages.
- the CLB signal is carried by an ISUP SUSPEND message (with an indication that the suspension request is network initiated) whilst the REANSWER signal is carried by an ISUP RESUME message (again with an indication that the suspension request is network initiated) .
- H.323 (H.225) does not. This means that in telecommunications networks which rely upon H.323 for carrying signalling information over at least part of a connection, the B- subscriber cannot suspend a call in the expected manner.
- a method of communicating signalling information between a pair of telecommunication networks employing ISUP or PSTN signalling, via a data network comprising using the H.323 protocol to communicate over the data network where signalling data is carried by a DSSl based protocol extended to provide for the transmission of ISUP/PSTN information which cannot be carried by DSSl.
- extended is used here to define that the DSSl based protocol is changed to accommodate new messages and/or message fields.
- ISUP/PSTN information not already catered for in DSSl is not merely transmitted over the data network by encapsulating them within "carrier" messages.
- the method is used for initiating a timer procedure at a call charging point of one of the ISUP/PSTN networks.
- the method comprises the further steps of detecting an on- hook state of a called party, and signalling a timer initiation request from the called party access point to the call charging point by means of an extension to the DSSl based protocol.
- a subsequent off-hook state of the called party may result in signalling a REANSWER indication to the call charging point whereupon the timer is cancelled.
- the on-hook state is detected at the access point of the called party, and the timer initiation request is signalled by means of the extension of the DSSl based protocol from the access point of the called party to the call charging point, the call charging point of the calling party being integrated or linked to the access point of the calling party.
- the timer initiation signal is a clear back signal (CLB) which causes an immediate initialisation of the call suspension timer which upon expiry will clear the call.
- CLB clear back signal
- the DSSl based protocol may be extended to include an extension for signalling REANSWER signal (RES) to the charging point of the calling party for cancelling the call suspension timer.
- RES REANSWER signal
- said data network which uses H.323 is a packet switched data network. More preferably, the network is an IP network. This network may be a LAN, an internetwork, the Internet, or a combination of two or more of these. In these cases, the H.323 protocol stack is provided over an IP protocol stack.
- a method of passing a Clear Back (CLB) and/or REANSWER message from a PSTN access point to a call charging point via a network which uses a DSSl based signalling protocol comprising defining call clearback and reanswer parameters and including one or other of the parameters as a
- Notification Indicator information element of a NOTIFY message of the DSSl based protocol for transmission over said network, in response to generation of a Clear Back or REANSWER message at the PSTN access point.
- the Notification Indicator information element is available for transmission from a called party access point to the charging centre or calling party access point in response to an off-hook operation at the called party, wherein the element conveys an off-hook notification value.
- the Notification Indicator information element in response to an on-hook operation by the called party, conveys an on-hook notification value.
- the method comprises polling the called party from the called party access point to detect an on-hook operation.
- said DSSl based signalling protocol is used by an H.323 network to establish and control connections over said network.
- apparatus for communicating signalling data between a pair of telecommunication networks employing ISUP or PSTN signalling, via a data network comprising means for using H.323 protocol to communicate over the data network where signalling data is carried by a DSSl based protocol extended to provide for the transmission of ISUP/PSTN messages which cannot be carried by DSSl.
- a method of communicating signalling data between a pair of telecommunication networks employing ISUP or PSTN signalling, via a data network comprising using H.323 protocol to communicate over the data network, wherein signalling data is carried by a Q.76x based protocol substituted in the H.323 protocol for DSSl.
- Figure 1 illustrates schematically a telecommunications network in which user and signalling data is carried between exchanges of the network via an IP network
- Figure 2 illustrates a flow of signalling information in the network of Figure 1;
- Figure 3 is a flow diagram illustrating the transmission of on-hook and off-hook signalling information in the network of Figure 1.
- the following description builds upon the disclosures of the ITU H.323 standard which makes mandatory the use of a DSSl based standard for establishing and maintaining a call connection between two H.323 enabled nodes.
- two PSTN exchanges 1,2 of a telecommunications network communicate with respective ISUP gateway exchanges 3,4 using the TUP signalling protocol.
- the ISUP exchanges in turn communicate with respective H.323 gateway nodes 5,6 using the ISUP interface.
- the gateway nodes 5,6 communicate with one another over a packet switched data network 7 (in this case an IP network) .
- the H.323 protocol layer is located above the TCP/IP layers in the protocol stacks of the two gateway nodes 5,6.
- the exchanges 1,2 provide PSTN access points to the telecommunications network for respective subscriber terminals 8,9.
- the terminal 8 from which the call is established is referred to as the A-subscriber whilst the other terminal 9 is referred to as the B-subscriber.
- the exchanges 1,2 may be located in the network of a single operator or may be located in networks of different operators.
- the terminals 8,9 may be connected to respective access exchanges 1,2 via intermediate routing nodes.
- the H.323 gateway nodes 5,6 make use of an extended version of the DSSl protocol specified by H.323. More particularly, the DSSl protocol is extended to enable certain PSTN (and associated ISUP) parameters to be transmitted over the TCP/IP network 7.
- the exchange 1 acts as a collector of information relevant to call charging, for a call initiated from the A-subscriber 8. More particularly, the exchange 1 passes information such as call initiation and termination signals, and calling and called party locations, to a Call Charging Point (or Toll Ticketing arrangement) 10 which calculates a toll ticket for a given call on the basis of the information received from the exchange 1 and certain predefined tariff information (including subscriber specific tariff information) .
- the Notification Indicator element is defined in the existing DSSl standard as having two meaningful values or states. These are:
- the Call Charging Point 10 In order to initiate the call suspension timer, the Call Charging Point 10 must receive a CLB signal.
- the exchange 2 polls the called party terminal 9 to detect the on-hook operation, and upon detection generates a CLB signal .
- the exchange 2 passes the CLB signal to the ISUP gateway exchange 4 which generates a corresponding SUSPEND signal which is forwarded to the H.323 gateway node 6.
- the gateway node 6 generates a NOTIFY message in which the Notification Indicator element has a value corresponding to the CLB signal .
- the gateway node 6 subsequently transmits the NOTIFY message over the IP network 7 to the initiating side gateway H.323 node 5.
- This gateway node 5 generates an ISUP SUSPEND message and passes it to the ISUP gateway exchange 3 which generates a CLB signal which is passed to the PSTN exchange 1.
- the CLB signal is forwarded to the CCP 10 which initialises the suspension timer in response.
- a call REANSWER message is generated and passed to the ISUP gateway exchange 4.
- the gateway exchange 4 generates an ISUP RESUME signal and passes it to the H.323 gateway node 6.
- a NOTIFY message is generated at the gateway node 6, the message including as a Notification Indicator element a value corresponding to a REANSWER message.
- This is relayed to the originating side H.323 gateway node 5, converted into an ISUP RESUME message and passed to the ISUP gateway exchange 3.
- a TUP REANSWER message is formed and passed to the PSTN exchange 1.
- the REANSWER message is passed to the CCP 10 which, in response, terminates the suspension timer so that the call is not subsequently terminated.
- the suspension and reanswer signalling flow is illustrated in Figure 2.
- Figure 3 is a flow chart illustrating the steps involved in the setting up of a call between the two terminals 8,9 and the subsequent termination of the call by the B- subscriber 9.
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2000567031A JP2002523991A (en) | 1998-08-24 | 1999-08-23 | Telecommunications system signaling |
EP99942902A EP1108333A1 (en) | 1998-08-24 | 1999-08-23 | Signalling in a telecommunications system |
CA002341169A CA2341169A1 (en) | 1998-08-24 | 1999-08-23 | Signalling in a telecommunications system |
AU56239/99A AU5623999A (en) | 1998-08-24 | 1999-08-23 | Signalling in a telecommunications system |
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FI981812A FI107005B (en) | 1998-08-24 | 1998-08-24 | Telephone call charging |
FI981812 | 1998-08-24 | ||
FI982319A FI105744B (en) | 1998-08-24 | 1998-10-26 | Signalling in a telecommunications system |
FI982319 | 1998-10-26 | ||
FI982320A FI105745B (en) | 1998-08-24 | 1998-10-26 | Signalling in a telecommunication system |
FI982320 | 1998-10-26 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2000011882A1 true WO2000011882A1 (en) | 2000-03-02 |
Family
ID=27241734
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP1999/006168 WO2000011882A1 (en) | 1998-08-24 | 1999-08-23 | Signalling in a telecommunications system |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP1108333A1 (en) |
JP (1) | JP2002523991A (en) |
CN (1) | CN1324546A (en) |
AU (1) | AU5623999A (en) |
CA (1) | CA2341169A1 (en) |
WO (1) | WO2000011882A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2002011375A1 (en) * | 2000-08-01 | 2002-02-07 | Siemens Aktiengesellschaft | Method for linking networks of different modes of transmission and associated devices |
WO2002013544A1 (en) * | 2000-08-08 | 2002-02-14 | Siemens Aktiengesellschaft | Method for the transmission of control information between a line-mediated and a packet-mediated communication network |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1318683A1 (en) * | 2001-12-10 | 2003-06-11 | Siemens Aktiengesellschaft | Method to transmit signalling messages and associated device, signalling message and program |
CN101304605B (en) * | 2007-05-10 | 2011-06-22 | 中兴通讯股份有限公司 | Method for implementing reanswer call |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1997016007A1 (en) * | 1995-10-25 | 1997-05-01 | Telecom Finland Oy | Gateway between networks using different protocols |
EP0841831A2 (en) * | 1996-11-07 | 1998-05-13 | AT&T Corp. | Wan-based voice gateway |
US5764750A (en) * | 1994-08-05 | 1998-06-09 | Lucent Technologies, Inc. | Communicating between diverse communications environments |
-
1999
- 1999-08-23 AU AU56239/99A patent/AU5623999A/en not_active Abandoned
- 1999-08-23 CA CA002341169A patent/CA2341169A1/en not_active Abandoned
- 1999-08-23 CN CN 99812457 patent/CN1324546A/en active Pending
- 1999-08-23 JP JP2000567031A patent/JP2002523991A/en active Pending
- 1999-08-23 WO PCT/EP1999/006168 patent/WO2000011882A1/en not_active Application Discontinuation
- 1999-08-23 EP EP99942902A patent/EP1108333A1/en not_active Withdrawn
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5764750A (en) * | 1994-08-05 | 1998-06-09 | Lucent Technologies, Inc. | Communicating between diverse communications environments |
WO1997016007A1 (en) * | 1995-10-25 | 1997-05-01 | Telecom Finland Oy | Gateway between networks using different protocols |
EP0841831A2 (en) * | 1996-11-07 | 1998-05-13 | AT&T Corp. | Wan-based voice gateway |
Non-Patent Citations (2)
Title |
---|
THOM G A: "H. 323: THE MULTIMEDIA COMMUNICATIONS STANDARD FOR LOCAL AREA NETWORKS", IEEE COMMUNICATIONS MAGAZINE,US,IEEE SERVICE CENTER. PISCATAWAY, N.J, vol. 34, no. 12, pages 52-56, XP000636454, ISSN: 0163-6804 * |
TOGA J ET AL: "ITU-T STANDARDIZATION ACTIVITIES FOR INTERACTIVE MULTIMEDIA COMMUNICATIONS ON PACKET-BASED NETWORKS: H.323 AND RELATED RECOMMENDATIONS", COMPUTER NETWORKS AND ISDN SYSTEMS,NL,NORTH HOLLAND PUBLISHING. AMSTERDAM, vol. 31, no. 3, pages 205-223, XP000700319, ISSN: 0169-7552 * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2002011375A1 (en) * | 2000-08-01 | 2002-02-07 | Siemens Aktiengesellschaft | Method for linking networks of different modes of transmission and associated devices |
WO2002013544A1 (en) * | 2000-08-08 | 2002-02-14 | Siemens Aktiengesellschaft | Method for the transmission of control information between a line-mediated and a packet-mediated communication network |
US7099303B2 (en) | 2000-08-08 | 2006-08-29 | Siemens Aktiengesellschaft | Method for transmitting control information between a line-switching and a packet-switching communications network |
Also Published As
Publication number | Publication date |
---|---|
CN1324546A (en) | 2001-11-28 |
JP2002523991A (en) | 2002-07-30 |
CA2341169A1 (en) | 2000-03-02 |
AU5623999A (en) | 2000-03-14 |
EP1108333A1 (en) | 2001-06-20 |
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