System and method for resolving address conflicts in a network

• US 20070097992A1
• Filed: 11/03/2005
• Published: 05/03/2007
• Est. Priority Date: 11/03/2005
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Ward, David, Singh, Pradeep
• Granted Patent: US 7,633,855 B2
• Time in Patent Office: Days
• US Class Current: 370/395.54
• CPC Class Codes: H04L 2101/604 Address structures or formats
• CPC Class Codes: H04L 61/5007 Internet protocol [IP] addresses
• CPC Class Codes: H04L 61/5046 Resolving address allocation conflicts; Testing of addresses testing when self-assigning an address H04L61/5092

Abstract

A system for resolving address conflicts in a network. In an illustrative embodiment, the system includes an address-configuration module that is adapted to assign addresses to one or more devices. The one or more devices are connected to the network via device interfaces. An interface-monitoring module communicates with the address-configuration module. The interface-monitoring module is adapted to determine when an address conflict involving plural addresses occurs and to provide a signal in response thereto. A conflict-resolution module is adapted to selectively terminate one or more device interfaces associated with the plural addresses in response to the signal and based on the addresses and one or more predetermined precedence rules. In a more specific embodiment, the system further employs a user interface for facilitating selectively adjusting the precedence rules. The conflict-resolution module runs one or more routines adapted to implement a static conflict-resolution policy, a longest-prefix policy, a highest-address policy, and/or an interface-identifier policy for Internet Protocol (IP) addresses.

Claims

1. A system for resolving address conflicts in a network, the system comprising:

an address-configuration module adapted to assign addresses to one or more devices, the one or more devices being coupled to the network via device interfaces;

an interface-monitoring module in communication with the address-configuration module, the interface-monitoring module being adapted to determine when an address conflict occurs and to provide a signal in response thereto, the address conflict involving plural addresses; and

a conflict-resolution module that is adapted to employ one or more predetermined precedence rules to selectively terminate, in response to the signal, one or more device interfaces associated with the plural addresses.

2. The system of claim 1 further including:

a user interface in communication with the conflict-resolution module, the user interface adapted to facilitate selectively adjusting the precedence rules.

3. The system of claim 2 wherein the addresses are Internet Protocol (IP) addresses.

4. The system of claim 3 wherein the conflict-resolution module includes:

one or more routines adapted to implement a static conflict-resolution policy.

5. The system of claim 4 wherein the static conflict-resolution policy includes:

instructions to give earlier-established addresses precedence over later-established addresses and to terminate interfaces associated with later-established addresses before terminating interfaces associated with earlier-established addresses in response to the signal.

6. The system of claim 3 wherein the conflict-resolution module includes:

one or more routines adapted to implement a longest-prefix policy.

7. The system of claim 6 wherein the longest-prefix policy includes:

instructions to give addresses exhibiting longer prefixes precedence over addresses exhibiting shorter prefixes and to terminate interfaces associated with addresses with shorter prefixes before terminating interfaces associated addresses with longer prefixes in response to the signal.

8. The system of claim 3 wherein the conflict-resolution module includes:

one or more routines adapted to implement a highest-address policy.

9. The system of claim 8 wherein the highest-address policy includes:

instructions to give addresses exhibiting higher IP addresses precedence over IP addresses exhibiting lower IP addresses and to terminate interfaces associated with lower IP addresses before terminating IP addresses associated with higher IP addresses in response to the signal.

10. The system of claim 3 wherein the conflict-resolution module includes:

one or more routines adapted to implement an interface-identifier policy.

11. The system of claim 10 wherein the interface-identifier policy includes:

instructions to establish address precedence values based on interface-identifiers and to terminate interfaces associated with lower precedence values in response to the signal.

12. A system for resolving address conflicts in a network, the system comprising:

an address-configuration module;

an interface-monitoring module in communication with the address-configuration module; and

a conflict-resolution module adapted to employ address precedence rules to selectively terminate device interfaces associated with an address configuration provided by the address-configuration module based on addresses associated with the address configuration that are involved in a conflict as determined by the interface-monitoring module.

13. A system for resolving address conflicts in a network, the system comprising:

first means for assigning addresses to one or more devices of the network, thereby configuring a portion of the network and establishing a network configuration in response thereto;

second means for establishing address precedence rules;

third means for monitoring the network for address conflicts and providing a signal in response thereto; and

fourth means for selectively resolving any of the address conflicts based on the precedence rules and in response to the signal.

14. A method for resolving address conflicts in a network, the method comprising:

assigning addresses to one or more devices of the network, thereby configuring a portion of the network and establishing a network configuration in response thereto;

selectively establishing or adjusting address precedence rules;

monitoring the network for address conflicts and providing a signal in response thereto; and

selectively resolving any of the address conflicts based on the precedence rules and in response to the signal.

15. The method of claim 14 further including:

a user interface in communication with a module that maintains the precedence rules, the user interface adapted to enable changing the precedence rules by a user of the user interface.

16. The method of claim 15 wherein the address conflicts include:

Internet Protocol (IP) address conflicts.

17. An apparatus for resolving address conflicts in a network comprising:

one or more processors;

a machine-readable medium including instructions executable by the one or more processors for

assigning addresses to one or more devices of the network, thereby configuring a portion of the network and establishing a network configuration in response thereto;

selectively establishing or adjusting address precedence rules;

monitoring the network for address conflicts and providing a signal in response thereto; and

selectively resolving any of the address conflicts based on the precedence rules and in response to the signal.