System and method for resolving address conflicts in a network

• US 7,633,855 B2
• Filed: 11/03/2005
• Issued: 12/15/2009
• 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
• Primary Examiner(s): Sheikh; Ayaz R
• Assistant Examiner(s): Aga; Sori A
• Application Number:
  US11/265,917
• Publication Number:
  US 20070097992A1
• Time in Patent Office: 1,503 Days
• Field of Search: None
• US Class Current: 370/216
• 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 in a network device adapted to assign Internet Protocol (IP) addresses to one or more devices, the one or more devices being coupled to the network via one or more device interfaces in an UP state to establish an IP connection from the network device through the one or more device interfaces on the network to the one or more devices to allow IP connectivity, the addresses being assigned by the network device wherein an address conflict occurs in a plurality of device interfaces in the UP state;

an interface-monitoring module in the network device in communication with the address-configuration module, the interface-monitoring module being adapted to determine when an address conflict occurs between the plurality of device interfaces and to provide a signal in response thereto, the address conflict involving plural addresses for the plurality of device interfaces, wherein the IP connection is established before the address conflict is determined; and

a conflict-resolution module that is adapted to employ one or more predetermined precedence rules to analyze the plural addresses for the plurality of device interfaces in the UP state and selectively terminate, in response to the signal, one or more device interfaces associated with the plural addresses, wherein termination of the one or more device interfaces brings one or more connections to terminate IP connectivity to the one or more device interfaces.

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 1 wherein the conflict-resolution module includes:

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

4. The system of claim 3 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.

5. The system of claim 1 wherein the conflict-resolution module includes:

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

6. The system of claim 5 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.

7. The system of claim 1 wherein the conflict-resolution module includes:

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

8. The system of claim 7 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.

9. The system of claim 1 wherein the conflict-resolution module includes:

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

10. The system of claim 9 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.

16. The system of claim 1, wherein the one or more predetermined precedence rules comprise a static policy, a longest-prefix policy, a highest-address policy and an interface-identifier policy, the conflict-resolution module adapted to:

determine an address conflict policy from the static policy, a longest-prefix policy, a highest-address policy, and an interface-identifier policy; and

apply the determined address conflict policy to selectively terminate the one or more device interfaces.

17. The system of claim 16, wherein determining the address conflict policy is based on a user selection via a user interface.

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

first means for assigning, by a network device, Internet Protocol (IP) addresses to one or more devices of the network, the one or more devices being coupled to the network via one or more device interfaces in an UP state to establish an IP connection from the network device through the one or more device interfaces on the network to the one or more devices to allow IP connectivity, the addresses being assigned by the network device wherein an address conflict occurs in a plurality of device interfaces in the UP state;

second means for establishing address precedence rules;

third means for monitoring, by the network device, the network for address conflicts between the plurality of device interfaces and providing a signal in response thereto, wherein the IP connection is established before the address conflict is determined; and

fourth means for selectively analyze the plural addresses for the plurality of device interfaces in the UP state and terminating one or more device interfaces for the plurality of device interfaces based on the precedence rules and in response to the signal, wherein termination of the one or more device interfaces brings one or more connections to terminate IP connectivity to the one or more device interfaces.

18. The apparatus of claim 11, wherein the one or more predetermined precedence rules comprise a static policy, a longest-prefix policy, a highest-address policy and an interface-identifier policy, the apparatus comprising:

fifth means for determining an address conflict policy from the static policy, a longest-prefix policy, a highest-address policy, and an interface-identifier policy; and

sixth means for applying the determined address conflict policy to selectively terminate the one or more device interfaces.

19. The apparatus of claim 18, wherein fifth means for determining the address conflict policy is based on a user selection via a user interface.

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

assigning, by a network device, Internet Protocol (IP) addresses to one or more devices of the network, the one or more devices being coupled to the network via one or more device interfaces in an UP state to establish an IP connection from the network device through the one or more device interfaces on the network to the one or more devices to allow IP connectivity, the addresses being assigned by the network device wherein an address conflict occurs in a plurality of device interfaces in the UP state;

establishing address precedence rules;

monitoring, by the network device, the network for address conflicts between the plurality of device interfaces and providing a signal in response thereto, wherein the IP connection is established before the address conflict is determined; and

selectively analyzing the plural addresses for the plurality of device interfaces in the UP state and terminating one or more device interfaces for the plurality of device interfaces based on the precedence rules and in response to the signal, wherein termination of the one or more device interfaces brings one or more connections to terminate IP connectivity to the one or more device interfaces.

13. The method of claim 12 further including:

changing the precedence rules based on input received from a user using a user interface.

14. The method of claim 13 wherein the address conflicts include:

Internet Protocol (IP) address conflicts.

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

one or more computer processors;

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

assigning, by the one or more computer processors, Internet Protocol (IP) addresses to one or more devices of the network, the one or more devices being coupled to the network via one or more device interfaces in an UP state to establish an IP connection front the apparatus through the one or more device interfaces on the network to the one or more devices to allow IP connectivity, the addresses being assigned the apparatus wherein an address conflict occurs in a plurality of device interfaces in the UP state;

establishing address precedence rules;

monitoring, by the one or more computer processors, the network for address conflicts between the plurality of device interfaces and providing a signal in response thereto, wherein the IP connection is established before the address conflict is determined; and

selectively analyzing the plural addresses for the plurality of device interfaces in the UP state and terminating one or more device interfaces for the plurality of device interfaces based on the precedence rules and in response to the signal, wherein termination of the one or more device interfaces brings one or more connections to terminate IP connectivity to the one or more device interfaces.

20. The apparatus of claim 15, wherein the one or more predetermined precedence rules comprise a static policy, a longest-prefix policy, a highest-address policy and an interface-identifier policy, the instructions for:

determining an address conflict policy from the static policy, a longest-prefix policy, a highest-address policy, and an interface-identifier policy; and

applying the determined address conflict policy to selectively terminate the one or more device interfaces.