Method for overload control in a telecommunications network and apparatus therefor

• US 20020159576A1
• Filed: 04/10/2002
• Published: 10/31/2002
• Est. Priority Date: 04/25/2001
• Status: Active Grant

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Adams, Richard Anthony
• Granted Patent: US 6,826,268 B2
• Time in Patent Office: Days
• US Class Current: 379/133
• CPC Class Codes: H04L 12/5602 Bandwidth control in ATM Networks, e.g. leaky bucket
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/12 Avoiding congestion; Recovering from congestion
• CPC Class Codes: H04L 47/15 in relation to multipoint traffic arrangements for broadcast or multicast in data networks H04L12/18
• CPC Class Codes: H04L 47/21 using leaky-bucket
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04L 47/70 Admission control; Resource allocation
• CPC Class Codes: H04L 47/745 Reaction in network
• CPC Class Codes: H04L 47/822 Collecting or measuring resource availability data
• CPC Class Codes: H04L 47/824 Applicable to portable or mobile terminals
• CPC Class Codes: H04L 47/826 Involving periods of time
• CPC Class Codes: H04Q 3/0091 Congestion or overload control
• CPC Class Codes: H04W 28/0289 Congestion control load shedding arrangements in network planning H04W16/08; performing reselection for handling the traffic H04W36/22; wireless traffic scheduling H04W72/12
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A method of suppressing overload in a telecommunications network involves the second node (1) receiving a signal that calls it has sent to a target node are being rejected and (2) reducing the rate of calls it sends to the target node in response.

The network could be a UMTS or other third generation (36) network.

Claims

1. A method of suppressing overload of a first node in a telecommunications network by the steps of a second node:

receiving a signal indicating that a call directed from the second node to the first node has been rejected and in response restricting the rate of transmission of calls from the second node to the first node to a predetermined level, and monitoring duration through a predetermined time period wherein if a further signal indicating that a call directed from the second node to the first node is received during the predetermined time period, the rate of transmission of calls from the second node to the first is restricted further to a further reduced predetermined level and duration through a further predetermined period is monitored.

2. A method according to claim 1 in which the or each predetermined level of restriction is selected dependent upon the measured rate of calls (D_measured) from the second node accepted by the first node.

3. A method according to claim 2, in which the measured rate of calls successfully transmitted is determined as the number of calls offered to the first node from the second node minus the number of rejected calls in a time interval.

4. A method according to claim 1, in which the or each predetermined level of restriction is dependent on whether the signal indicating rejection of a call indicates severe overload or moderate overload.

5. A method according to claim 1, in which the steps of restricting and monitoring are repeated until no signal indicating that a call directed from the second node to the first node has been rejected is received during the latest predetermined period.

6. A method according to claim 5, in which if no signals indicating that a call directed from the second node to the first node has been rejected is received during the latest predetermined period a reduced level of restriction is applied, and duration through a further predetermined period is monitored.

7. A method according to claim 6, in which the level of restriction is reduced by increasing allowed call rate by a predetermined factor in the range 1.01 to 1.07.

8. A method according to claim 7, in which the predetermined factor is, or is about, 1.03.

9. A method according to claim 6, in which the step of reducing the level of restriction is repeated after each predetermined time period in which no signal indicating that a call directed from the second node to the first node has been rejected is received.

10. A method according to claim 1 in which all the restrictions are removed dependent on the call rate (O_new) of calls offered to the second node for the first node being measured as becoming sufficiently low.

11. A method according to claim 1 in which the rate of calls (D_measured) accepted by the first node from the second node and rate of calls (O_new) offered to the second node for the first node are measured continually or regularly.

12. A method according to claim 1, in which the rate of calls (D_measured) accepted by the first node from the second node and the rate of calls offered to the second node for the first node are measured from receipt of the signal indicating that a call from the second node to the first node has been rejected, until restriction(s) are lifted.

13. A method according to claim 1 in which, upon removal of the restrictions on the rate of transmission of calls from the second node to the first node, the latest level of restriction which was applied is stored in a memory for reuse as the predetermined level to be applied should overload reoccur in the future.

15. A telephone network according to claim 14, in which the restricting means is operative to repeat the steps of restricting and monitoring until no signal indicating that a call directed from the second node to the first node has been rejected is received during the latest predetermined period.

16. A telephone network according to claim 14 in which the first node and second node are telephone exchanges.

17. A telephone network according to claim 16, in which the first node and second node are telephone exchanges connected by switch circuitry and trunk lines.

18. A telephone network according to claim 14, in which the first node is connected to a plurality of second nodes, each operative to receive a signal that a call directed from itself to the first node has been rejected and operative in response to both restrict the rate of transmission of calls from itself to the first node.

20. A telecommunications apparatus according to claim 19 which is a telephone exchange.

21. A computer program loadable onto telecommunications apparatus in a telecommunications network which when run executes the method according to claim 1.

14. A telecommunications network comprising a first node and a second node, the second node comprising receiving means operative to receive a signal indicating that a call directed from the second node to the first node has been rejected, and restricting means operative in response to both restrict the rate of transmission of calls from the second node to the first node to a predetermined level and start its timer to monitor duration through a predetermined period, wherein, in use, if a further signal indicating that a call directed from the second node is received by the receiving means during the predetermined period being measured by the timer, the restricting means reduces the rate of transmission of calls from the second node to the first node to a further predetermined level and restarts the timer.

19. A telecommunications apparatus comprising receiving means operative to receive a signal indicating that a call sent from said apparatus has been rejected, the apparatus comprising restricting means operative in response to restrict the rate of calls sent out and start its timer to monitor duration through a predetermined period, wherein in use, if a further signal indicating that a call sent from said apparatus has been rejected is received by said receiving means during the predetermined period measured by the timer, the restricting means further reduces the rate of calls sent out.