Intelligent network with distributed service control function

• US 6,504,923 B1
• Filed: 03/10/1998
• Issued: 01/07/2003
• Est. Priority Date: 01/15/1997
• Status: Expired due to Term

• Current Assignee: British Telecommunications PLC (BT Group PLC)
• Original Assignee: British Telecommunications PLC (BT Group PLC)
• Inventors: Swale, Richard P
• Primary Examiner(s): Geckil, Mehmet B.
• Assistant Examiner(s): Kang, Paul H
• Application Number:
  US09/029,933
• Time in Patent Office: 1,764 Days
• Field of Search: 370/428, 370/309, 370/244, 370/250, 709/223, 709/224, 709/232, 709/238, 379/207, 379/209.01, 379/221.09, 379/221.08, 379/221.1, 379/221.12, 379/221.14, 379/221.15, 379/265.02
• US Class Current: 379/221.09
• CPC Class Codes: H04Q 3/0029 Provisions for intelligent networking

Abstract

An intelligent network in which the service switching points (SSPs) consult a lookup table for services which require the use of a service control point (SCP), and send respective request messages containing a service type field. If such a service is one which can be handled by an SCP whose LAN (for the intercommunication of its various data processors) has become partitioned because of, say, a LAN fault, the SSP writes a first value for service type into the field, and if the service is one which must not be handled by a partitioned SCP, the SSP writes a second value. The request messages are sent via service transfer points (STPs). The network includes a transmission controller which has first and second states. Any SCP which detects that its LAN has become partitioned commands the transmission controller to enter the second state. In the first state the transmission controller is transparent to all messages regardless of the contents of the service type field, but in the second state it does not pass requests of the second service type. In one embodiment, each STP is integrally constructed with a respective transmission controller. In another embodiment, each SCP includes one or more respective transmission controller disposed at the junction of its signalling servers and the signalling link from the STP.

Claims

1. An intelligent communications network having a service switching function (SSF) comprising a plurality of service switching points (SSPs), a service control function (SCF) comprising a plurality of service control points (SCPs), and a signalling transfer function (STF) comprising at least one signalling transfer point (STP) and respective signalling links, in which network:

each SCP comprises,

signalling receiving means,

a distributed processing architecture comprising a plurality of data processors each connected to a data communications network arranged such that each data processor can communicate with each other processor, and

a network state detector means arranged to detect that the data communications network is in a partitioned state and thus unable to provide communication from each data processor to each other data processor, and in response to output a predetermined command;

each SSP

(a) has a stored list of services which require the use of the SCF, each service being associated with a respective preassigned service type, this being either a first service type indicative of services that may be processed by a partitioned SCP or a second service type indicative of services that must not be processed by a partitioned SCP, and

(b) is arranged to respond to each call which relates to a service requiring the use of the SCF, by obtaining from the stored list its associated preassigned service type, and by sending to the SCF via the STF a message signal having a service type field into which the SSP has written the obtained service type; and

there is provided message signal control means disposed between the signalling receiving means of the SCPs and the SSF and arranged to respond to receipt of said predetermined command from the network state detector means by changing from a first state, in which it permits transmission of all message signals, to a second state, in which it blocks transmission of all message signals whose service type field contains said second service type.

2. An intelligent network as claimed in claim 1, wherein said signalling receiving means of each SCP comprises a respective plurality of signalling servers, and said message signal control means comprises a respective transmission controller for each signalling server.

3. An intelligent network as claimed in claim 1, wherein said signalling receiving means of each SCP comprises a respective plurality of signalling servers, at least one signalling server being connected to a plurality of STPs, and wherein said message signal control means comprises a respective transmission controller for each of said plurality of STPs.

4. An intelligent network as claimed in claim 2, wherein each transmission controller is disposed at the junction of the SCF and the STF.

5. An intelligent network as claimed in claim 1, wherein said message signal control means comprises a respective transmission controller disposed integrally with the or each STP.

6. An intelligent network as claimed in claim 1, wherein in each SCP, the respective network state detector means is distributed and comprises respective first detector means in each data processor, each respective first detector means being arranged in accordance with a first predetermined algorithm to detect that the data communications network has become partitioned by analysis of interprocessor messages received by its associated data processor.

7. An intelligent network as claimed in claim 1, wherein, in each SCP, the data communications network comprises a plurality of interconnected nodes, each node being connected to a respective plurality of the data processors, and the respective network state detector means is constituted by a respective one of the data processors at each of the nodes, said respective data processor being arranged to monitor interprocessor messages handled by its associated node and to detect, in accordance with a first predetermined algorithm, that the data communications network has become partitioned by analysis of said monitored interprocessor messages.

8. An intelligent network as claimed in claim 1, wherein, in each SCP, the respective network state detector means is constituted by one of the data processors arranged to monitor interprocessor messages handled by the data communications network and to detect, in accordance with a first predetermined algorithm, that the data communications network has become partitioned by analysis of said monitored interprocessor messages.

9. An intelligent network as claimed in claim 1, wherein, in each SCP, each data processor is arranged to transmit on the respective data communications network a respective predetermined message at predetermined times in accordance with a second predetermined algorithm, and the respective network state detector means is arranged to receive said predetermined messages transmitted on the respective data communications network and in accordance with said second predetermined algorithm to output said predetermined command upon detection of a lack of reception of a said predetermined message.

10. An intelligent network as claimed in claim 9, wherein, in each SCP, the respective network state detector means is arranged in accordance with said second predetermined algorithm to treat the transmission of an interprocessor message by a said data processor as equivalent to the transmission of a said predetermined message by the said data processor, and to transmit a said predetermined message in the event that a predetermined length of time has elapsed since the said data processor has transmitted a message of any type.

11. An intelligent network as claimed in claim 10, wherein, in each SCP, each data processor is arranged, in the event that it transmits an interprocessor message at substantially the same time as the due time for transmission of a said predetermined message, to delay transmission of said predetermined message until after the end of said interprocessor message.

12. An intelligent network as claimed in claim 6, wherein, in each SCP, each data processor is arranged to transmit on the respective data communications network a respective predetermined message at predetermined times in accordance with a predetermined algorithm, and the respective network state detector means is arranged to receive said predetermined messages transmitted on the respective data communications network and in accordance with said predetermined algorithm to output said predetermined command upon detection of a lack of reception of a said predetermined message;

in each SCP, the network state detector means further comprises, associated with each data processor, a respective second detector means for detecting a said lack of reception of a said predetermined message.

13. An intelligent network as claimed in claim 7, wherein, in each SCP, each data processor is arranged to transmit on the respective data communications network a respective predetermined message at predetermined times in accordance with a second predetermined algorithm, and the respective network state detector means is arranged to receive said predetermined messages transmitted on the respective data communications network and in accordance with said second predetermined algorithm to output said predetermined command upon detection of a lack of reception of a said predetermined message;

each said respective one of the data processors at each of the nodes constitutes a manager for the data processors associated with its respective node and comprises a respective second detector means for detecting a said lack of reception of a said predetermined message.

14. The network of claim 1, wherein the message signal control means changes from the first state, in which the message signal control means permits transmission of all message signals sent from the SSP to the SCF, to the second state, in which the message signal control means blocks transmission of all said message signals whose service type field contains said second service type.

15. A service control point (SCP) for use in an intelligent communications network, the SCP comprising

a distributed processing architecture comprising a plurality of signalling servers each connected to a data communications network arranged such that each signalling server can communicate with each other signalling server, and

a network state detector arranged to detect that the data communications network is in a partitioned state and thus unable to provide communication from each signalling server to each other signalling server, and in response to output a predetermined fault signal;

and

message signal transmission controller for receiving message signals from a signal transfer point of the intelligent communications network and responsive to said predetermined fault signal to allow or deny transmission to the signalling servers in dependence upon whether the content of a service type field of a received message signal indicates a service that may be processed by a partitioned SCP or a service that must not be processed by a partitioned SCP.

16. An SCP as claimed in claim 15, wherein the network state detector is distributed and comprises a respective first detector in each signalling server, each respective first detector being arranged in accordance with a first predetermined algorithm to detect that the data communications network has become partitioned by analysis of interprocessor messages received by its associated signalling server.

17. An SCP as claimed in claim 15, wherein the data communications network comprises a plurality of interconnected nodes, each node being connected to a respective plurality of the signalling servers, and the network state detector is constituted by a respective one of the signalling servers at each of the nodes, said respective signalling servers being arranged to monitor interprocessor messages handled by its associated node and to detect, in accordance with a first predetermined algorithm, that the data communications network has become partitioned by analysis of said monitored interprocessor messages.

18. An SCP as claimed in claim 15, wherein the network state detector is constituted by one of the signalling servers arranged to monitor interprocessor messages handled by the data communications network and to detect, in accordance with the first predetermined algorithm, that the data communications network has become partitioned by analysis of said monitored interprocessor messages.

19. An SCP as claimed in claim 15, wherein each signalling server is arranged to transmit on the data communications network a respective predetermined message at predetermined times in accordance with a predetermined algorithm, and the network state detector is arranged to receive said predetermined messages transmitted on the data communications network and in accordance with said predetermined algorithm to send said predetermined fault signal upon detection of a lack of reception of a said predetermined message.

20. An SCP as claimed in claim 19, wherein the network state detector is arranged in accordance with said predetermined algorithm to treat the transmission of an interprocessor message by a said signalling server as equivalent to the transmission of a said predetermined message by said signalling server, and to transmit a said predetermined message in the event that a predetermined length of time has elapsed since the said signalling server has transmitted a message of any type.

21. An SCP as claimed in claim 19, wherein each signalling server is arranged, in the event that it transmits an interprocessor message at substantially the same time as the due time for transmission of a said predetermined message, to delay transmission of said predetermined message until after the end of said interprocesser message.

22. An SCP as claimed in claim 16, wherein each signalling server is arranged to transmit on the data communications network a respective predetermined message at predetermined times in accordance with a predetermined algorthim, and the network state detector is arranged to receive said predetermined messages transmitted on the data communications network and in accordance with said predetermined algorithm to send said predetermined fault signal upon detection of a lack of reception of a said predetermined message;

and

the network state detector further comprises, associated with each signalling server, a respective second detector for detecting a said lack of reception of a said predetermined message.

23. An SCP as claimed in claim 17, wherein each signalling server is arranged to transmit on the data communications network a respective predetermined message at predetermined times in accordance with a second predetermined algorithm, and the network state detector is arranged to receive said predetermined messages transmitted on the data communications network and in accordance with said second predetermined algorithm to send said predetermined fault signal upon detection of a lack of reception of a said predetermined message;

and

each said respective one of the signalling servers at each of the nodes constitutes a manager for the signalling servers associated with its respective node and comprises a respective second detector for detecting a said lack of reception of a said predetermined message.

24. A service control point (SCP) for use in an intelligent communications network, the SCP comprising:

a first interface for communication with a network center for processing fault signals;

a second interface for communication with a signalling transfer point (STP) of the intelligent network;

a distributed processing architecture including a plurality of signalling serves each connected to a data communications network arranged such that each signalling server can communicate with each other signalling server and;

a data communications network fault detector arranged to detect when each signalling server is not able to communicate with each other signalling server over the date communications network, and in response to provide to said second interface a fault signal for transmission to said STP.

25. An SCP as claimed in claim 24, wherein the network fault detector is distributed and comprises a respective first detector in each signalling server, each respective first detector being arranged in accordance with a first predetermined algorithm to detect that the data communication network has become partitioned by analysis of interprocessor messages received by its associated signalling server.

26. An SCP as claimed in claim 24, wherein the data communications network comprises a plurality of interconnected nodes, each node being connected to a respective plurality of the signalling servers, and the network fault detector is constituted by a respective one of the signalling servers at each of the nodes, said respective signalling servers being arranged to monitor interprocessor messages handled by its associated node and to detect, in accordance with a first predetermined algorithm, that the data communications network has become partitioned by analysis of said monitored interprocessor messages.

27. An SCP as claimed in claim 24, wherein the network fault detector is constituted by one of the signalling servers arranged to monitor interprocessor messages handled by the data communications network and to detect, in accordance with the first predetermined algorithm, that the data communications network has become partitioned by analysis of said monitored interprocessor messages.

28. An SCP as claimed in claim 24, wherein each signalling server is arranged to transmit on the data communications network a respective predetermined message at predetermined times in accordance with a predetermined algorithm, and the network fault detector is arranged to receive said predetermined messages transmitted on the data communications network and in accordance with said predetermined algorithm to send said fault signal upon detection of a lack of reception of a said predetermined message.

29. An SCP as claimed in claim 28, wherein the network fault detector is arranged in accordance with said predetermined algorithm to treat the transmission of an interprocessor message by a said signalling server as equivalent to the transmission of a said predetermined message by the said signalling server, and to transmit a said predetermined message in the event that a predetermined length of time has elapsed since the said signalling server has transmitted a message of any type.

30. An SCP as claimed in claim 28, wherein each signalling server is arranged, in the event that it transmits an interprocessor message at substantially the same time as the due time for transmission of a said predetermined message, to delay transmission of said predetermined message until after the end of said interprocessor message.

31. An SCP as claimed in claim 25, wherein each signalling server is arranged to transmit on the data communications network a respective predetermined message at predetermined times in accordance with a predetermined algorithm, and the network fault detector is arranged to receive said predetermined messages transmitted on the data communications network and in accordance with said predetermined algorithm to send said fault signal upon detection of a lack of reception of a said predetermined message;

and

the network fault detector further comprises, associated with each signalling server, a respective second detector for detecting a said lack of reception of a said predetermined message.

32. An SCP as claimed claim 26, wherein each signalling server is arranged to transmit on the data communications network a respective predetermined message at predetermined times in accordance with a second predetermined algorithm, and the network fault detector is arranged to receive said predetermined messages transmitted on the data communications network and in accordance with said second predetermined algorithm to send said fault signal upon detection of a lack of reception of a said predetermined message;

and

each said respective one of the signalling servers at each of the nodes constitutes a manager for the signalling server associated with its respective node and comprises a respective second detector for detecting a said lack of reception of a said predetermined message.

33. A method of operating an intelligent communications network which comprises a plurality of service switching points (SSPs), a service control function (SCF) comprising a plurality of service control points (SCPs), and a signalling transfer function (STF) comprising at least one signalling transfer point (STP), in which network each SCP comprises a distributed processing architecture comprising a plurality of data processors each connected to a data communications network arranged such that each data processor can communicate with each other processor, the method comprising the steps of:

(a) storing in each SSP a list of services which require the use of the SCF, each service being stored in association with a respective preassigned service type, this being either a first service type indicative of services that may be processed by a partitioned SCP or a second service type indicative of services that must not be processed by a partitioned SCP;

(b) detecting that the data communications network is in a partitioned state and thus unable to provide communication from each data processor to each other data processor, and in response outputting a predetermined command;

(c) receiving said predetermined command at message signal control means and in response changing from a first state, in which it permits transmission of all message signals, to a second state, in which it blocks transmission of all message signals whose service type field contains said second service type; and

responding at the SSPs to each call which relates to a service requiring the use of the SCF, by obtaining from the stored list its associated preassigned service type, and by sending to the SCF via the STF a message having a service type field into which the SSP has written the obtained service type.

34. The method of claim 33, wherein the message signal control means changes from the first state, in which the message signal control means permits transmission of all message signals sent from the SSP to the SCF, to the second state, in which the message signal control means blocks transmission of all said message signals whose service type field contains said second service type.

35. A service switching point (SSP) for use in an intelligent communications network comprising a service control function (SCF) comprising a plurality of service control points (SCPs), the SSP:

having a stored list of services which require the use of the SCF, each service being associated with a respective preassigned service type, this being either a first service type indicative of services that may be processed by a partitioned SCP or a second service type indicative of services that must not be processed by a partitioned SCP, and

being arranged to respond to each call which relates to a service requiring the use of the SCF, by obtaining from the stored list its associated preassigned service type, and by outputting a message having a service type field into which the SSP has written the obtained service type.

36. A signalling transfer point (STP) for use in an intelligent communications network comprising a plurality of service switching points (SSPs), and a service control function (SCF);

the STP being integral with a message signal controller arranged to respond to receipt of a particular fault signal from the SCF by changing from a first state, in which transmission of message signals from the SSPs to the SCF is unconditional, to a second state, in which transmission of message signals from the SSPs to the SCF is conditional upon a service type field of message signals received from the SSPs containing a particular service type corresponding to services whose message signals may be processed by an SCF having that particular fault.