Data collection based on ifAlias

To collect data based on ifAlias, specify in the Extended Descriptor OID_I=ifInOctets (to retrieve inbound traffic values) or OID_I=ifOutOctets (outbound traffic). Do not specify the interface index number.

The value of the ifAlias must also be specified for the particular interface. The keyword is IFALIAS. For the above example ifAlias values, to collect inbound traffic values for the network interface that represents "to LAN", put

OID_I=ifInOctets; IFALIAS="to LAN"

into the Extended Descriptor of a PI tag such as tag1. (Note that double quotes must be used because of the space between "to" and "LAN".)

During data retrieval for tag1, PI SNMP obtains all the ifAlias names from the router. It then matches the IFALIAS value of tag1 with these ifAlias names to determine the interface index number. In this example, the interface number is 2. PI SNMP then internally constructs the OID

interfaces.ifTable.ifEntry.ifInOctets.2

and sends the appropriate request to the router.

If the router reboots and the SNMP agent reassigns interface indices such that

ifMIB.ifMIBObjects.ifXTable.ifXEntry.ifAlias.1 = remote office

ifMIB.ifMIBObjects.ifXTable.ifXEntry.ifAlias.2 = to ISP

ifMIB.ifMIBObjects.ifXTable.ifXEntry.ifAlias.3 = to LAN

PI SNMP still reads correct values for tag1 because it will now internally construct the OID

interfaces.ifTable.ifEntry.ifInOctets.3

in order to get the data from the router.