Automatic hardware failure detection and recovery for distributed max sessions server

• US 7,272,649 B1
• Filed: 09/30/1999
• Issued: 09/18/2007
• Est. Priority Date: 09/30/1999
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Patil, Kavita Shekhar, Roden, Thomas Anthony, Boyd, Pauline Chen, Knight, John, Bui, Sonny, Shively, Darrell Myers II
• Primary Examiner(s): Caldwell; Andrew
• Assistant Examiner(s): BLAIR, DOUGLAS B
• Application Number:
  US09/410,511
• Time in Patent Office: 2,910 Days
• Field of Search: 709223-229, 710/240, 707/10, 714/25, 714/43, 713/201
• US Class Current: 709/225
• CPC Class Codes: G06F 11/0709 in a distributed system consisting of a plurality of standalone computer nodes, e.g. clusters, client-server systems
• CPC Class Codes: G06F 11/0751 Error or fault detection not based on redundancy power supply failures G06F1/30; network fault management H04L41/06
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 63/0892 by using authentication-authorization-accounting [AAA] servers or protocols
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• 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 Max Sessions Server (MSS) automatically detects hardware and communications failures. Upon detection, counters are adjusted accordingly to maintain an accurate count of users or groups of users on a system. A database of unique identifiers for each connection is maintained, where the unique identifier is a concatenation of a Network Access Server (NAS) and the connection'"'"'s incoming NAS node number. If a user requests permission to log into the system, the MSS first checks the database to determine if the unique identifier is already logged in. If so, then a hardware or communications failure has occurred and the MSS must make the appropriate adjustments to the database and counter. Additionally, the MSS or an authentication, authorization and accounting (AAA) server will periodically check to determine if an NAS has ceased communicating over a particular length of time and relay any failures to the MSS. If the NAS has experienced a hardware or communications failure, then the MSS must make the appropriate adjustments to the database and counters for all sessions logged in from the failed NAS. Finally, the MSS may broadcast the failure to all MSSs associated with the NAS on the system.

Claims

1. A method for a Max Sessions Server (MSS) of a data communications network to keep a count of the sessions used at a given time by a group of users and to correct the count to compensate for abnormal disconnections of users belonging to the group, the method comprising:

assigning a unique identification value (UIV) to each port of a network access server (NAS) of the data communications network;

maintaining a master list having a plurality of entries, each entry containing at least (a) a UIV for a port associated with a logged in user and (b) respective group identification information for the logged in user;

periodically checking a NAS to determine if it has become non-operational; and

responding to the non-operational status of a NAS by removing all entries having UIVs for ports associated with the non-operational NAS from the master list and decrementing the count of the sessions used by the number of removed entries that correspond to the group,

wherein the assigning includes performing a concatenation, for each port of the NAS, of a unique identifier for the NAS and a port identifier for the port.

2. The method of claim 1 wherein:

the periodically checking is performed with an Authentication, Authorization and Accounting Server (AAA) associated with the MSS.

3. The method of claim 1, further comprising:

transmitting a communication to another MSS on the data communications network to inform it of the non-operational status of a NAS.

4. The method of claim 3, further comprising:

receiving a communication from another MSS on the data communication network advising of the non-operational status of a NAS; and

responding to the communication by removing all entries having UIVs associated with the non-operational NAS from the master list and decrementing the count of the sessions used by the number of removed entries that correspond to the group.

5. A method for a Resource Control Server (RCS) of a data communications network to keep a count of a particular resource used at a given time by a group of users and to correct the count to compensate for abnormal disconnections of users belonging to the group, the method comprising:

assigning a unique identification value (UIV) to each port of a network access server (NAS) of the data communications network;

maintaining a master list having a plurality of entries, each entry containing at least (a) a UIV for a port associated with a logged in user and (b) respective group identification information for the logged in user;

periodically checking a NAS to determine if it has become non-operational; and

responding to the non-operational status of a NAS by removing all entries having UIVs for ports associated with the non-operational NAS from the master list and decrementing the count of the sessions used by the number of removed entries that correspond to the group,

wherein the assigning includes performing a concatenation, for each port of the NAS, of a unique identifier for the NAS and a port identifier for the port.

6. The method of claim 5 wherein:

the periodically checking is performed with an Authentication, Authorization and Accounting Server (AAA) associated with the MSS.

7. The method of claim 5, further comprising:

transmitting a communication to another MSS on the data communications network to inform it of the non-operational status of a NAS.

8. The method of claim 7, further comprising:

receiving a communication from another MSS on the data communication network advising of the non-operational status of a NAS; and

responding to the communication by removing all entries having UIVs associated with the non-operational NAS from the master list and decrementing the count of the particular resource used by the number of removed entries that correspond to the group.

9. A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform a method for a Max Sessions Server (MSS) of a data communications network to keep a count of the sessions used at a given time by a group of users and to correct said count to compensate for abnormal disconnections of users belonging to said group, the method comprising:

assigning a unique identification value (UIV) to each port of a network access server (NAS) of the data communications network;

maintaining a master list having a plurality of entries, each entry containing at least (a) a UIV for a port associated with a logged in user and (b) respective group identification information for the logged in user;

periodically checking a NAS to determine if it has become non-operational; and

responding to the non-operational status of a NAS by removing all entries having UIVs for ports associated with the non-operational NAS from the master list and decrementing the count of the sessions used by the number of removed entries that correspond to the group,

wherein the assigning includes performing a concatenation, for each port of the NAS, of a unique identifier for the NAS and a port identifier for the port.

10. A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform a method for a Resource Control Server (RCS) of a data communications network to keep a count of a particular resource used at a given time by a group of users and to correct the count to compensate for abnormal disconnections of users belonging to the group, the method comprising:

assigning a unique identification value (UIV) to each port of a network access server (NAS) of the data communications network;

maintaining a master list having a plurality of entries, each entry containing at least (a) a UIV for a port associated with a logged in user and (b) respective group identification information for the logged in user;

periodically checking a NAS to determine if it has become non-operational; and

responding to the non-operational status of a NAS by removing all entries having UIVs for ports associated with the non-operational NAS from the master list and decrementing the count of the sessions used by the number of removed entries that correspond to the group,

wherein the assigning includes performing a concatenation, for each port of the NAS, of a unique identifier for the NAS and a port identifier for the port.

11. A Max Sessions Server (MSS) apparatus for use on a data communications network to keep a count of the sessions used at a given time by a group of users and to correct the count to compensate for abnormal disconnections of users belonging to the group, the apparatus - comprising:

means for assigning a unique identification value (UIV) to each port of a network access server (NAS) of the data communications network;

means for maintaining a master list having a plurality of entries, each entry containing at least (a) a UIV for a port associated with a logged in user and (b) respective group identification information for the logged in user;

means for periodically checking a NAS to determine if it has become non-operational; and

means for responding to the non-operational status of a NAS configured to remove all entries having UIVs for ports associated with the non-operational NAS from the master list and decrement the count of the sessions used by the number of removed entries that correspond to the group,

wherein the means for assigning is configured to perform a concatenation, for each port of the NAS, of a unique identifier for the NAS and a port identifier for the port.

12. The apparatus of claim 11, wherein:

the means for periodically checking queries an Authentication, Authorization and Accounting Server (AAA) associated with the MSS.

13. The apparatus of claim 11, further comprising:

means for transmitting a communication to another MSS over the data communications network to inform it of the non-operational status of a NAS.

14. The apparatus of claim 13, further comprising:

means for receiving a communication from another MSS over the data communication network advising of the non-operational status of a NAS; and

means for responding to the communication configured to remove all entries having UIVs associated with the non-operational NAS from the master list and decrement the count of the sessions used by the number of removed entries that correspond to the group.

15. A Resource Control Server (RCS) apparatus for use on a data communications network to keep a count of a particular resource used at a given time by a group of users and to correct the count to compensate for abnormal disconnections of users belonging to the group, the apparatus comprising:

means for assigning a unique identification value (UIV) to each port of a network access server (NAS) of the data communications network;

means for maintaining a master list having a plurality of entries, each entry containing at least (a) a UIV for a port associated with a logged in user and (b) respective group identification information for the logged in user;

means for periodically checking a NAS to determine if it has become non-operational; and

means for responding to the non-operational status of a NAS configured to remove all entries having UlYs for ports associated with the non-operational NAS from the master list and decrement the count of the sessions used by the number of removed entries that correspond to the group,

wherein the means for assigning is configured to perform a concatenation, for each port of the NAS, of a unique identifier for the NAS and a port identifier for the port.

16. The apparatus of claim 15, wherein:

the means for periodically checking is configured to query an Authentication, Authorization and Accounting Server (AAA) associated with the MSS.

17. The apparatus of claim 15, further comprising:

means for transmitting a communication to another MSS over the data communications network to inform it of the non- operational status of a NAS.

18. The apparatus of claim 15, further comprising:

means for receiving a communication from another MSS over the data communication network advising of the non-operational status of a NAS; and

means for responding to the communication configured to remove all entries having UIVs associated with the non-operational NAS from the master list and decrement the count of the particular resource used by the number of removed entries that correspond to the group.