Hello!

Say there is an array of network interfaces available on a networking device and these differ in it's nature:

• 9 FastEthernet interfaces
• 1 Gigabit Ethernet interface
• 1 Serial interface
• 1 terminal line
• 1 Virtual Private Network (VPN) Module

Such devices may provide network interface info in both ifHCInOctets and ifInOctets counters, and provide interfaces with only ifInOctets counters.
In SNMP tree, these will have different traffic counters present: ifInOctets and ifHCInOctets. With the current SNMP discovery implementation, if there is no entry for a certain SNMP OID, the discovery will fail by itself with the following message: Cannot accurately apply filter: no value received for macro "{#IFHCINOCTETS}".

As a workaround, user requires to define two different discovery rules as can be observed in Template Module Interfaces Simple SNMPv2 and Template Module Interfaces SNMPv2 out of the box templates.
It would be nice, if SNMP discovery would be able to process missing entries in SNMP tree in case index of device is present.

Sample SNMP tree layout for a reference:

IF-MIB::ifInOctets.1 = Counter32: 4266470707
IF-MIB::ifInOctets.2 = Counter32: 0
.3, .4, .5 ...... NO GAPs
IF-MIB::ifInOctets.12 = Counter32: 0
IF-MIB::ifInOctets.13 = Counter32: 4217786513
IF-MIB::ifInOctets.14 = Counter32: 1162860867

<...>

IF-MIB::ifHCInOctets.7 = Counter64: 0
IF-MIB::ifHCInOctets.8 = Counter64: 159481902502
GAP
GAP........
IF-MIB::ifHCInOctets.11 = Counter64: 151918525828
IF-MIB::ifHCInOctets.12 = Counter64: 0
IF-MIB::ifHCInOctets.14 = Counter64: 1014752389343