Cisco Cisco Unified Operations Manager 8.0 White Paper

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Ping-Based Discovery

You can choose to add a ping sweep (by selecting the Ping Sweep check box) in addition to or instead of the

Cisco Discovery Protocol, ARP table, and route table discovery process.

When using a ping sweep discovery, IP phones and other nonvoice devices (for example, network printers, Sun

servers, or PCs) with an IP address in the specified ping sweep range will also be discovered. These devices are

populated in the DCR and are placed in the unmanaged device state in Operations Manager.

Note that Operations Manager manages and discovers IP phones indirectly. Operations Manager discovers IP

phones through querying the Layer 2 switch (to which the phones are connected) and the Cisco Unified

Communications Manager (to which the phones are registered). Operations Manager does not directly manage

the IP phones, since SNMP is not currently supported on the IP phones. IP phones are discovered because they

respond to an Internet Control Message Protocol (ICMP) ping.

To avoid populating the DCR with network printers and other nonvoice network devices, use the IP Exclude filter

on the Discovery page.

In IP telephony deployments, phones acquire their IP addresses from a DHCP server. This DHCP server usually

has a pool of IP addresses configured for IP phones. The IP phone address pool can be specified in the IP

exclude filter, thereby preventing IP phones from being populated in the DCR.

Credential Discovery and MIB II Information

Automatic discovery uses the list of credentials configured on the Credentials page (Administration > Device

Management > Device Configuration > Discovery Configurations > Credentials) to determine the correct

SNMPv2/v3 credentials and/or HTTP (or HTTPS) credentials for the device. After the correct credentials are

determined, automatic discovery retrieves MIB II information from the device and populates this information in the

DCR.

Autodiscovery IP Address Filters

Both the include and exclude filters can be applied for the automatic discovery process. The exclude filter is

applied first, before the include filter. You provide the order of the filters in the include and exclude filter lists, and

the filters are applied strictly in this order. After a device IP address satisfies a filter, other filters will not be applied

to the device.

For example, suppose that you configure the filters as follows:

Exclude Filter

12.*.*.*, 12.12.*.*

Include Filter

*.*.*.*, 14.*.*.*

In the above case, the filter 12.*.*.* overrides 12.12.*.*, and so 12.12.*.* will never be applied and is thus not

required. Similarly, *.*.*.* overrides 14.*.*.*.

The effect of these two filter lists operating in conjunction is that all device IP addresses except those in the range

12.[0-255].[0-255].[0-255] will be discovered and populated in the DCR.

Remember that the exclude filter is applied before the include filter.

Consider three devices with the IP addresses 12.12.12.12, 14.14.14.14, and 20.20.20.20. We show a few

examples of filter settings that determine which of these devices are discovered and populated in the DCR, and

which are excluded.