Cisco Cisco IOS Software Release 12.4(6)T

OSPF must be configured on the router.

Before choosing to switch from the current interface numbers to the SNMP MIB-II interface ID 
numbers, you should understand the following concepts:

If you use Simple Network Management Protocol (SNMP) for your OSPF network, configuring the 
OSPF: SNMP ifIndex Value for Interface ID in OSPFv2 and OSPFv3 Data Fields feature can be 
beneficial for the following reasons:

Using the SNMP MIB-II ifIndex (interface index) identification numbers to identify OSPF 
interfaces makes it easier for network administrators to identify interfaces because the numbers will 
correspond to the numbers that they will see reported by SNMP.

When examining link-state advertisements (LSAs), the value used in fields that have the interface 
ID will be the same as the value that is reported by SNMP.

When looking at the output of the show ipv6 ospf interface command, the interface ID number will 
have the same value that is reported by SNMP.

Using the SNMP MIB-II IfIndex is also suggested, but not required, by the OSPF RFC 2328 for 
OSPFv2 and the RFC 2740 for OSPFv3.

The user chooses for OSPF interfaces to use the SNMP MIB-II ifIndex number by entering the 
interface-id snmp-if-index command for a specific OSPF process. If an interface under the specific 
OSPF process does not have an SNMP ifIndex number, OSPF will not be enabled on that interface.

For OSPFv2, the ifIndex number is used for the Link Data field in the Router LSA for unnumbered 
point-to-point interfaces and sham links. When the interface-id snmp-if-index command is entered, the 
affected LSAs will immediately be reoriginated.