Method and apparatus for maintaining active calls during failover of network elements

• US 20060250946A1
• Filed: 04/19/2005
• Published: 11/09/2006
• Est. Priority Date: 04/19/2005
• Status: Active Grant

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Croak, Marian, Eslambolchi, Hossein
• Granted Patent: US 8,593,939 B2
• Time in Patent Office: Days
• US Class Current: 370/216
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/1104 Session initiation protocol [SIP]
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

A method and apparatus for keeping transitory state in a packet network so that in the event of a failover of a network element, existing active calls can be quickly re-established by the packet network or briefly held in a suspended state until the affected network element returns to a healthy state is disclosed.

Claims

1. A method for maintaining active calls during failover in a communication network, comprising:

transferring call states of the active calls in an active network element to a standby network element if said failover relates to said active network element;

transferring call states of the active calls in an active component of said active network element to a standby component within said active network element if said failover relates to said active component of said network element; and

switching over the active calls to said standby network element or said standby component within said active network element by activating said transferred call states of said active calls.

2. The method of claim 1, wherein said communication network is a Voice over Internet Protocol (VoIP) network or a Service over Internet Protocol (SoIP) network.

3. The method of claim 1, wherein said transferring comprises:

keeping said active calls in a suspended active state.

4. The method of claim 1, wherein said call states transferring is initiated by a network maintenance event, an active network element failure event, or an active component within an active network element failure event.

5. The method of claim 1, wherein said activating comprises:

modifying said active calls from suspended active states to active states.

6. The method of claim 1, wherein said switching over active calls to said standby network element comprises:

modifying a current media path of said actives calls to a new media path to pass through said standby network element.

7. The method of claim 1, wherein if said transferring and switching fail to complete within a pre-specified period of time, said active calls are dropped.

8. A computer-readable medium having stored thereon a plurality of instructions, the plurality of instructions including instructions which, when executed by a processor, cause the processor to perform the steps of a method for maintaining active calls during failover in a communication network, comprising:

transferring call states of the active calls in an active network element to a standby network element if said failover relates to said active network element;

transferring call states of the active calls in an active component of said active network element to a standby component within said active network element if said failover relates to said active component of said network element; and

switching over the active calls to said standby network element or said standby component within said active network element by activating said transferred call states of said active calls.

9. The computer-readable medium of claim 8, wherein said communication network is a Voice over Internet Protocol (VoIP) network or a Service over Internet Protocol (SoIP) network.

10. The computer-readable medium of claim 8, wherein said transferring comprises:

keeping said active calls in a suspended active state.

11. The computer-readable medium of claim 8, wherein said call states transferring is initiated by a network maintenance event, an active network element failure event, or an active component within an active network element failure event.

12. The computer-readable medium of claim 8, wherein said activating comprises:

modifying said active calls from suspended active states to active states.

13. The computer-readable medium of claim 8, wherein said switching over active calls to said standby network element comprises:

modifying a current media path of said actives calls to a new media path to pass through said standby network element.

14. The computer-readable medium of claim 8, wherein if said transferring and switching fail to complete within a pre-specified period of time, said active calls are dropped.

15. An apparatus for maintaining active calls during failover in a communication network, comprising:

means for transferring call states of the active calls in an active network element to a standby network element if said failover relates to said active network element;

means for transferring call states of the active calls in an active component of said active network element to a standby component within said active network element if said failover relates to said active component of said network element; and

means for switching over the active calls to said standby network element or said standby component within said active network element by activating said transferred call states of said active calls.

16. The apparatus of claim 15, wherein said communication network is a Voice over Internet Protocol (VoIP) network or a Service over Internet Protocol (SoIP) network.

17. The apparatus of claim 15, wherein each of said transferring means keeps said active calls in a suspended active state.

18. The apparatus of claim 15, wherein said call states transfer is initiated by a network maintenance event, an active network element failure event, or an active component within an active network element failure event.

19. The apparatus of claim 15, wherein said activating comprises:

modifying said active calls from suspended active states to active states.

20. The apparatus of claim 15, wherein said switching means modifies a current media path of said actives calls to a new media path to pass through said standby network element.