Configuring Interface Index Persistence; Snmp Examples; Displaying The Snmp Configuration - Cisco Catalyst 8540 MSR Configuration Manual

Chapter 15 Configuring ATM Accounting, RMON, and SNMP

Configuring Interface Index Persistence

The interface index persistence feature allows interfaces to be identified with unique values that remain
constant even when a device is rebooted. These interface identification values apply to network
monitoring and management using SNMP.
The interface index (ifIndex) value is one of the most commonly used identifiers in SNMP-based
network management applications. IfIndex is a unique identifying number associated with a physical or
logical interface; for most software, the ifIndex is the "name" of the interface.
Although no requirement exists in the relevant RFCs that the correspondence between particular ifIndex
values and their interfaces be maintained across reboots, applications such as device inventory, billing,
and fault detection increasingly depend on the maintenance of this correspondence.
It is currently possible to poll the switch router at regular intervals to correlate the interfaces to the
ifIndex, but it is not practical to poll this interface constantly. If this data is not correlated constantly,
however, the data may become invalid because of a reboot or the insertion of a new module into the
switch router between polls. Therefore, ifIndex persistence is the only way to guarantee data integrity.
IfIndex persistence also means that the mapping between the ifDescr object values and the ifIndex object
values (generated from the IF-MIB) will be retained across reboots.
For detailed overview and configuration information about this feature see the chapter,
"Interface Index Persistence" of the IOS documentation.

SNMP Examples

The following example permits any SNMP to access all objects with read-only permission using the
community string named "public." The ATM switch router will also send ATM interface traps to the
hosts "192.180.1.111" and "192.180.1.33" using SNMPv1 and to the host "192.180.1.27" using
SNMPv2C. The community string "public" is sent with the traps.
Switch(config)# snmp-server community public
Switch(config)# snmp-server enable traps atm if-event
Switch(config)# snmp-server host 192.180.1.27 version 2c public
Switch(config)# snmp-server host 192.180.1.111 version 1 public
Switch(config)# snmp-server host 192.180.1.33 public
The following example sends the SNMP traps to the host specified by the name myhost.cisco.com. The
community string is defined as "comaccess".
Switch(config)# snmp-server enable traps
Switch(config)# snmp-server host myhost.cisco.com comaccess snmp
The following example sends the ATM interface event SNMP traps (using the atm if-event keywords)
and the "admin" username to address "172.30.2.160":
Switch(config)# snmp-server host 172.30.2.160 traps admin atm if-event

Displaying the SNMP Configuration

To display the SNMP configuration, use the following privileged EXEC command:
OL-7396-01
ATM Switch Router Software Configuration Guide
Configuring SNMP
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