Method and system for detecting changes in a network using simple network management protocol polling

• US 20070276932A1
• Filed: 05/23/2006
• Published: 11/29/2007
• Est. Priority Date: 05/23/2006
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Sankaran, Ganesh Chennimalai
• Granted Patent: US 7,991,865 B2
• Time in Patent Office: Days
• US Class Current: 709/223
• CPC Class Codes: H04L 41/0213 Standardised network management protocols, e.g. simple network management protocol [SNMP]
• CPC Class Codes: H04L 41/046 comprising network management agents or mobile agents therefor
• CPC Class Codes: H04L 43/10 Active monitoring, e.g. heartbeat, ping or trace-route

Abstract

In an embodiment, methods and systems have been provided for detecting changes in a network using improved Simple Network Management Protocol (SNMP) polling that reduces network traffic. Examples of changes in the network include, but are not limited to, configuration and behavioral changes in a network device, and response of network device to a network change. A Network Management Station (NMS) periodically polls Management Information Base (MIB) groups instead of periodically polling individual MIB object instances. The NMS receives the Aggregate Change Identifiers (ACIs) of MIB groups in response to polling, from a SNMP agent. The changes in the received ACIs represent the changes in the MIB groups. A change in an MIB group represents changes in the MIB object instances of the MIB group. The ACIs can be checksum, timestamp, and a combination of number of MIB object instances in a group and checksum of the MIB group.

Claims

1. A method for detecting changes in a network for updating a Network Management Station (NMS), the network comprising the NMS and network devices, each of the network devices comprising a Simple Network Management Protocol (SNMP) agent and Management Information Base (MIB) objects, the method comprising:

periodically polling an MIB group formed by grouping MIB object instances; and

polling the MIB object instances of the MIB group only if a change is detected in an Aggregate Change Identifier (ACI) of the MIB group.

2. The method of claim 1, wherein the ACI is selected from a group consisting of a timestamp of the MIB group, a checksum of the MIB group, and a combination of number of MIB object instances in an MIB group and a checksum of the MIB group.

3. The method of claim 2, wherein the checksum is ah incremental checksum.

4. The method of claim 1, wherein the MIB object instances are polled using SNMP protocol polling for detecting changes in the network.

5. A method for detecting changes in a network for updating a Network Management Station (NMS), the network comprising the NMS and network devices, each of the network devices comprising a Simple Network Management Protocol (SNMP) agent and Management Information Base (MIB) objects, the method comprising:

computing an Aggregate Change Identifier (ACI) of an MIB group formed by grouping MIB object instances; and

sending the computed ACI to the NMS in response to a request for the MIB group, wherein the request is made by the NMS.

6. The method of claim 5, wherein a network device includes a multi-level hierarchy of MIB groups.

7. The method of claim 5, wherein the MIB object are grouped if the MIB object instances change due to at least one of:

configuration change of the network device, behavioral change of the network device, and response of the network device to a change in network.

8. The method of claim 5, wherein the MIB group is formed by grouping a predefined number of MIB object instances, the MIB object instances forming a tabular MIB object.

9. The method of claim 8, wherein the ACIs of the tabular MIB object are defined on the basis of the predefined number.

10. The method of claim 8, wherein the predefined number is a table compression factor.

11. A system for detecting changes in a network for updating a Network Management Station (NMS), the network comprising the NMS and network devices, each of the network devices comprising a Simple Network Management Protocol (SNMP) agent and Management Information Base (MIB) objects, the system comprising:

means for periodically polling an MIB group formed by grouping MIB object instances; and

means for polling the MIB object instances of the MIB group only if a change is detected in an Aggregate Change Identifier (ACI) of the MIB group.

12. A system for detecting changes in a network for updating a Network Management Station (NMS), the network comprising the NMS and network devices, each of the network devices comprising a Simple Network Management Protocol (SNMP) agent and Management Information Base (MIB) objects, the system comprising:

means for computing an Aggregate Change Identifier (ACI) of an MIB group formed by grouping MIB object instances; and

means for sending the computed ACI to the NMS in response to a request for the MIB group, wherein the request is made by the NMS.

13. A machine-readable medium including instructions executable by the processor comprising:

one or more instructions for periodically polling an MIB group formed by grouping MIB object instances; and

one or more instructions for polling the MIB object instances of the MIB group only if a change is detected in an Aggregate Change Identifier (ACI) of the MIB group.

14. A machine-readable medium including instructions executable by the processor comprising:

one or more instructions for computing an Aggregate Change Identifier (ACI) of an MIB group formed by grouping MIB object instances; and

one or more instructions for sending the computed ACI to the NMS in response to a request for the MIB group, wherein the request is made by the NMS.