Table of Contents

Device Discovery Method

Cisco Discovery Protocol
Ping Sweep Starting IP Address
Ping Sweep IP Address Range

Defining the Community Strings
Starting or Stopping Device Discovery
Completing Optional Device Discovery Tasks
Viewing Current Settings
Viewing Discovery Status

Using Device Discovery

Device discovery helps you discover Cisco devices in your network to ensure that they are Y2K compliant. After the devices are discovered, a file that lists the discovered devices is automatically exported to the inventory application.

Once a device has been discovered and added to the inventory database, it will not be redetected in subsequent discoveries, and it will remain in the inventory database.

Because device discovery uses SNMP and CDP, which are standard but unreliable protocols, you will need to run device discovery several times to discover all Cisco devices in your network.

To set up and run the discovery process in your network and to transfer the information to the inventory application, complete the following steps:

• Define the method to use to discover devices.

• Define the community strings, if necessary.

• Start, stop, or schedule device discovery.

• Start or schedule device discovery for it to run (device discovery does not run periodically).

To tailor your device discovery, you can:

• Set export options to stop the automatic file export to the inventory application.

• Set up filters to exclude certain IP addresses from the discovery process.

• Set up filters to include only certain IP addresses from the discovery process.

• Modify configuration parameters, such as timeouts and retries.

After you have finished setting all the device discovery options, you can:

• View your current settings.

• View device discovery status.

Device Discovery Method

The three methods of device discovery are discussed in the following sections:

• CDP

• Ping Sweep Starting IP Address

• Ping Sweep IP Address Range

Cisco Discovery Protocol

This method discovers only CDP-enabled Cisco devices in your network. It takes the least amount of time to complete, and is useful in networks that are made up entirely of Cisco devices. Products acquired by Cisco do not support CDP. CDP is supported in Cisco IOS release 10.0 and later, and is not supported by WAN switches.

Ping Sweep Starting IP Address

This method discovers all SNMP-enabled Cisco devices in your network. It takes the longest of the three methods to complete, but is the most comprehensive. In this method, device discovery finds all the devices connected to the device whose IP address is given. The process is repeated recursively until all devices are reached.

Ping Sweep IP Address Range

This method discovers a specific range of SNMP-enabled Cisco devices in your network. It takes more time to complete than the CDP method, but less time than the Ping Sweep Starting IP Address method. It is useful if you know the unique IP subnets in the network. In this method, device discovery finds all the devices within a range of user-supplied IP addresses. It also provides the ability to find unique IP address ranges from a single device, and performs device discovery using the address ranges. See Table 5-1 for a comparison of each method.

Defining the Community Strings

Use this option to set the SNMP read-only community strings.

Discovery uses community strings to determine whether a device supports SNMP. For each community string you enter, discovery waits for the SNMP timeout to determine if the device supports that community. For example, if you have specified three community string names, and the SNMP timeout is set for 5000 milliseconds (ms), it will take 15,000 ms for discovery to ascertain if the device supports SNMP.

Starting or Stopping Device Discovery

Use this option to start or stop the device discovery immediately or to schedule it to start at a predefined time. If more than one user starts, stops, or schedules device discovery at the same time, the system will accept only one request for device discovery, and will send an error message to the other.

Completing Optional Device Discovery Tasks

Depending on your login level, you can complete the following optional tasks to prepare for device discovery:

• Setting export options---Use this option to specify whether to export the device discovery file to the inventory application.

• Setting exclude filters---Use this option to define filters for excluding devices from device discovery.

• Setting include filters---Use this option to define filters for including only certain devices in device discovery.

• Setting advanced options---Use this option to change the default parameters set up for device discovery.

Viewing Current Settings

To view your current settings for device discovery, select Tasks > Device Discovery > View Current Settings.

Viewing Discovery Status

To view the status of device discovery, select Tasks > Device Discovery > Discovery Status.

Posted: Wed Dec 15 14:36:45 PST 1999
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