Active call context reconstruction for primary/backup resource manager servers

• US 7,526,533 B1
• Filed: 11/30/1999
• Issued: 04/28/2009
• Est. Priority Date: 11/30/1999
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Shively, Darrell Myers II, Bue, Brian Lo, Nadeau, Larry
• Primary Examiner(s): Dinh; Khanh Q
• Application Number:
  US09/452,285
• Time in Patent Office: 3,437 Days
• Field of Search: 709/200, 709/203, 709/208, 709/216, 709/218, 709/222, 709/226, 709/228, 709/224, 709/232, 709/234, 709/201, 709/220, 709/227, 370/10, 370/5, 370/229, 710/105, 714/4, 714/13, 714/15
• US Class Current: 709/220
• CPC Class Codes: G06F 11/1658 Data re-synchronization of a redundant component, or initial sync of replacement, additional or spare unit
• CPC Class Codes: G06F 11/2028 eliminating a faulty processor or activating a spare
• CPC Class Codes: G06F 11/2038 with a single idle spare processing component
• CPC Class Codes: G06F 11/2046 where the redundant components share persistent storage G06F11/2043 takes precedence
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups
• CPC Class Codes: H04M 7/0084 Network monitoring; Error detection; Error recovery; Network testing

Abstract

A method and apparatus for network server recovery maintains an ongoing call by reconstructing its call context from a server-state attribute (SSA) that is generated by a first server, recorded in separate storage and retrieved by a second server in the event that a connection to the first server is interrupted. The SSA encodes call data that can be used to enable a server to maintain the call. The separate storage is preferably associated with a network access server (NAS) that does not itself use the SSA.

Claims

1. A backup server for enabling a data communications network to recover from a local server failure, the backup server comprising:

an information packet requester configured to request an information packet from a memory associated with the a network access server (NAS) in response to a call received from the NAS, if the call information is not available to the backup server, the information packet associated with an ongoing call placed by a call-in user via the NAS, the information packet containing call information for maintaining connection of the ongoing call if the local server fails;

an encoder associated with the local server and configured to generate an information packet associated with an ongoing call placed by the call-in user via the NAS, wherein the information packet containing call information for maintaining connection of the ongoing call if the local server fails;

a sender configured to transmit for transmitting the information packet from the encoder to a memory associated with the NAS, the information packet being stored in the memory;

a call coupler associated with the NAS and configured to couple for coupling the call to the local server if the local server does not fail, the call coupler further configured to couple and for coupling the call to the backup server if the local server fails;

an information packet receiver responsive to the local server failure, the information packet receiver receiving the information packet from a memory associated with a network access server (NAS), the NAS configured to couple capable of coupling a call placed from the call-in user to the data communications network and providing a network connection to the local server; and

a parser configured to reconstruct for reconstructing the call information from the information packet, such that the backup server maintains the ongoing call to the data communications network.

2. A backup server according to claim 1, wherein the call information comprises server-state attribute (SSA) having an attribute/value pair that can be parsed into a plurality of separate data entries.

3. A backup server according to claim 1, wherein the information packet further comprises a plurality of aggregated data elements from a call attribute table.

4. A backup server according to claim 3, wherein the plurality of aggregated data elements are separated by the parser for reconstructing the call information from the information packet.

5. A backup server according to claim 1, wherein the call information comprises at least one of:

Dialed Number Information Service (DNIS) address;

call type;

Calling Line Identification (CLID); and

service accounting information.

6. A system for maintaining a call placed by a call-in user to a data communications network, the system comprising:

a memory associated to a network access server (NAS), the NAS configured to couple capable of coupling a call placed from the call-in user to the data communications network and providing a network connection to a local server;

an encoder associated with the local server and configured to generate an information packet associated with an ongoing call placed by the call-in user via the NAS, wherein the information packet containing call information for maintaining connection of the ongoing call if the local server fails;

a sender configured to transmit for transmitting the information packet from the encoder to a memory associated with the NAS, the information packet being stored in the memory;

a call coupler associated with the NAS and configured to couple for coupling the call to the local server if the local server does not fail, the call coupler further configured to couple and for coupling the call to the backup server if the local server fails;

an information packet forwarder configured to transmit for transmitting the information packet from the associated memory to the backup server if the local server fails the information packet forwarder further comprising an information packet requester associated with the backup server for requesting the information packet from the memory associated with the NAS in response to the call received from the NAS, if the call information is not available to the backup server; and

a parser associated with the backup server and configured to reconstruct for reconstructing the call information from the information packet such that the backup server can recover the call information and serve the call without disconnecting the user from the network.

7. A system according to claim 6, wherein the information packet forwarder further comprises:

an information packet sender associated with the NAS and configured to transmit for transmitting the information packet in response to a request from the information packet requester.

8. A system according to claim 6, wherein the call information comprises at least one of:

Dialed Number Information Service (DNIS) address;

call type;

Calling Line Identification (CLID); and

service accounting information.

9. A server backup system for maintaining an ongoing call placed by a call-in user to a network, the system comprising:

a backup server connected to the network, the backup server configured to service of servicing the call;

an encoder associated with a server servicing the call, the encoder generating an information packet associated with an ongoing call placed by the call-in user via a network access server (NAS) configured to couple capable of coupling the call from the user to the network, the NAS further configured to provide and providing a network connection to the server, the information packet containing call information for maintaining connection of the ongoing call;

a sender associated with the server, the sender configured to transmit transmitting the information packet to a memory associated with the NAS, the memory configured to store˜

the information packet;

a call coupler associated with the NAS, the call coupler configured to roll˜

over the call to the backup server if the server fails;

an information packet requester associated with the backup server, the information packet requester configured to request for requesting the information packet from the memory associated with the NAS in response to the call received from the NAS, if the call information is not available to the backup server; and

a parser associated with the backup server and configured to reconstruct, for reconstructing the call information from the information packet.

10. A server backup system according to claim 9, wherein the call information comprises server-state attribute data having an attribute/value pair that can be parsed into a plurality of separate data entries.

11. A server backup system according to claim 9, wherein the information packet further comprises a plurality of aggregated data elements from a call attribute table.

12. A server backup system according to claim 11, wherein the plurality of aggregated data elements of the information packet are separated by the parser for reconstructing the call information from the information packet.

13. A server backup system according to claim 9, wherein the server is a resource pool manager server (RPMS).

14. A server backup system according to claim 9, further comprising:

a failure detector associated with the NAS; and

configured to detect for detecting the failure of the server.

15. A server backup system according to claim 9, wherein the call information comprises at least one of:

Dialed Number Information Service (DNIS) address;

call type;

Calling Line Identification (CLID); and

service accounting information.

16. A server backup system for maintaining an ongoing call placed by a call-in user to a network, the system comprising:

a first server connected to the network and configured to service for servicing the call;

a second server connected to the network and configured to service for servicing the call if the first server fails; and

a network access server (NAS) configured to couple capable of coupling a call placed by a call-in user to the network and providing a network connection to a server, the NAS coupling the call from the call-in user to the first server if the first server does not fail, and coupling the call to the second server if the first server fails, the NAS including a memory associated therewith,

wherein the first server comprises;

an encoder configured to generate for generating an information packet associated with an ongoing call placed by the call-in user via the NAS, the information packet containing call information for maintaining connection of the ongoing call if the first server fails; and

a sender configured to transmit for transmitting the information packet from the encoder to the memory associated with the NAS, the memory storing the information packet, and

wherein the second server comprises;

an information packet requester configured to request for requesting the information packet from the memory in response to the call received from the NAS, if the call information is not available to the second server; and

a parser configured to reconstruct for reconstructing the call information from the information packet.

17. A server backup system according to claim 16, wherein the NAS further comprises:

a failure detector configured to detect for detecting the failure of the second server.

18. A server backup system according to claim 16, wherein the first server is a resource pool manager server (RPMS) and the second server is a backup RPMS.

19. A server backup system according to claim 16, wherein the call information comprises at least one of:

Dialed Number Information Service (DNIS) address;

call type;

Calling Line Identification (CLID); and

service accounting information.

20. A method performed by backup server for enabling a data communications network to recover from a local server failure, the method comprising:

if the local server fails and if an information packet associated with an ongoing call placed by a call-in user is not available, requesting the information packet from a memory associated with a network access server (NAS) in response to a call placed from the call-in user to the data communications network, the information packet containing call information for maintaining connection of the ongoing call if the local server fails;

receiving the an information packet from the a memory in response to the a local server failure, the NAS configured to couple capable of coupling a call placed from a call-in user to the data communications network, the NAS further configured to provide and providing a network connection to a local server; and

reconstructing the call information from the information packet so as to maintain the ongoing call to the data communications network.

21. A method according to claim 20, wherein the call information comprises server-state attribute (SSA) data having an attribute/value pair, the reconstructing comprising:

parsing the SSA data into a plurality of separate data entries.

22. A method according to claim 21, further comprising:

petitioning to the NAS for the information packet after the NAS requests the call information; and

sending the call information to the NAS after completing the reconstructing.

23. A method for maintaining a call placed by a call-in user to a data communications network, the method comprising:

generating an information packet associated with an ongoing call placed by the call-in user via a network access server (NAS), wherein the information packet containing call information of an ongoing call for maintaining connection of the call if the local server fails;

transmitting the information packet to the memory associated with the NAS, the information packet being stored in a memory associated with the NAS, the NAS configured to the call-in user to the data communications network and providing a network connection to the local server;

coupling the call to the local server if the local server does not fail, and coupling the call to the backup server if the local server fails;

transmitting the information packet from the memory associated with NAS to the backup server via an information packet requester associated with the backup server if the local server fails and the information is not available to the backup server; and

reconstructing the call information from the information packet such that the backup server can recover the call context and serve the ongoing call without disconnecting the user from the network.

24. An apparatus for enabling a data communications network to recover from a local server failure, the data communications network including a network access server (NAS) configured to couple capable of coupling a call placed from a call-in user to the data communications network and providing a network connection to the local server, the NAS having a memory associated therewith, the apparatus comprising:

means for, if the local server fails and if an information packet associated with an ongoing call placed by a call-in user is not available, requesting the information packet from a memory associated with a network access server (NAS) in response to a call placed from the call-in user to the data communications network, the information packet containing call information for maintaining connection of the ongoing call if the local server fails;

means for receiving the an information packet from the a memory associated in response to the a local server failure, the NAS configured to couple a call placed from a call-in user to the data communications network, the NAS further configured to provide and providing a network connection to a local server; and

means for reconstructing the call information from the information packet so as to maintain the ongoing call to the data communications network.

25. An apparatus according to claim 24, wherein the call information comprises server-state attribute (SSA) data having an attribute/value pair, the means for reconstructing comprising:

means for parsing the SSA data into a plurality of separate data entries.

26. An apparatus according to claim 25, further comprising:

means for petitioning to the NAS for the information packet after the NAS requests the call information; and

means for sending the call information to the NAS after completing the reconstructing.