Network maintenance

• US 7,693,273 B2
• Filed: 02/20/2003
• Issued: 04/06/2010
• Est. Priority Date: 02/20/2002
• Status: Active Grant

• Current Assignee: British Telecommunications PLC (BT Group PLC)
• Original Assignee: British Telecommunications PLC (BT Group PLC)
• Inventors: Rice, Douglas H
• Primary Examiner(s): Al Aubaidi; Rasha S
• Application Number:
  US10/503,055
• Publication Number:
  US 20050084092A1
• Time in Patent Office: 2,602 Days
• Field of Search: 379/229, 379/221.01, 379/221.04, 379/1.01
• US Class Current: 379/229
• CPC Class Codes: H04Q 3/0029 Provisions for intelligent networking

Abstract

A method of signalling in an AIN, in which in an SSP, the initial message of a new transaction is addressed to a Service Global Title (SGT). The SSP translates that SGT to a first address of the first choice SCP. The SCP responds with an acknowledgement message which has a second address of the SCP as its source address, and includes the Nodal Global Title (NGT) of that SCP. The SSP sends subsequent messages for that transaction addressed to that NGT, and the SSP translates that NGT to the second address of the SCP. When the SCP is taken out of service, the first address is made unavailable, so the SSP sends new initial messages to the second choice SCP, but subsequent messages for existing transactions may still be sent to the second address of the first choice SCP. When all existing transactions have ceased, the SCP is taken out of service.

Claims

1. In a communications network, wherein a source network unit conducts a new transaction for a function of that network by:

(a) selecting a member of a respective function-associated pool of transaction-processing units, each having a service status of in-service (IS) and having a first network address for receipt of initial transaction signalling messages and a second network address for receipt of subsequent transaction signalling messages;

(b) sending an initial transaction signalling message to that first network address of the selected member, and then sending subsequent signalling messages of that transaction to the second network address of the selected member;

a method of changing the service status of a particular transaction-processing unit of the pool to out-of-service (OOS), the method comprising;

(c) changing the service status of the first network address of the particular member from IS to OOS;

(d) continuing to process subsequent signalling messages received at the second network address of the particular transaction-processing unit in respect of transactions currently being processed by that particular transaction-processing unit; and

(e) changing the service status of that particular transaction-processing unit from IS to OOS upon detecting actual or effectual completion of all such transactions currently being processed by that particular transaction-processing unit.

2. The method as claimed in claim 1 wherein (b) is performed only if the source network unit has ascertained that the service status of the first network address of the selected member is IS;

and wherein (c) comprises sending a message to each potential source network unit indicating that the service status of the first network address of the particular member has changed from IS to OOS.

3. The method as claimed in claim 2 wherein (d) comprises broadcasting such a message to each potential source network unit.

4. The method as claimed in claim 2 wherein (d) comprises sending respective such messages to the potential source network units in stages.

5. The method as claimed in claim 1 wherein each transaction-processing unit possesses a respective Internet Protocol address having first and second associated port addresses and constituting the first and second network addresses of that transaction-processing unit.

6. A unit for use in a communications network, the unit comprising:

an application arranged to provide a specific function;

transaction signalling message handling means having first and second network addresses and arranged to handle transaction signalling messages in respect of that application in accordance with a transaction protocol;

marking means responsive to a requirement for a change of service status of the unit from in-service (IS) to out-of-service (OOS) for marking the service status of the first network address as OOS;

means for detecting that the unit is actually or effectively not currently processing any transactions; and

means responsive to such a detection by the detecting means for changing the service status of the unit from IS to OOS,

wherein the transaction signalling message handling means is arranged;

to respond to receipt from a source network unit of the communications network of a transaction signalling message of which a called party address part includes the first network address, such a transaction signalling message being hereinafter referred to as an initial transaction signalling message for a transaction, by creating a respective transaction instance and storing in that transaction instance the calling party address of that initial transaction signalling message,

to respond to an acknowledgment from the application in respect of a received initial transaction signalling message by creating, in accordance with the newly created transaction instance corresponding to that received initial transaction signalling message, a return transaction signalling message of which a calling party address part includes the second network address, and

to respond to receipt from a source network unit of the communications network of a transaction signalling message of which a called party address part contains the second network address, such a transaction signalling message being hereinafter referred to as a subsequent transaction signalling message of an existing transaction, by processing that subsequent transaction signalling message in accordance with the stored transaction instance corresponding to that existing transaction.

7. The unit as claimed in claim 6 wherein the marking means is arranged to send a message to potential source network units of the communications network indicating that the service status of the first network address has changed from IS to OOS.

8. The unit as claimed in claim 7 wherein the marking means is arranged to broadcast such a message to each potential source network unit.

9. The unit as claimed in claim 7 wherein the marking means is arranged to send respective such messages to the potential source network units in stages.

10. The unit as claimed in claim 6 wherein the first and second network addresses are constituted by a single Internet Protocol address having first and second associated port addresses.