I am configuring several voice gateways using Cisco ISR4321/K9 (IOS XE version 16.6.2) routers with "NIM-1MFT-T1/E1 - T1/E1 Serial Module" (and "PVDM4-32 Voice DSP Module") connecting E1 ISDN/PRI interface to CUCM and MS SfB servers connected via SIP trunks.
I want to monitor ISDN usage using SNMP, "isdnBearerOperStatus" objects as recommended in
https://www.cisco.com/c/en/us/support/docs/ip/simple-network-management-protocol-snmp/42782-channelusage42782.html
using PRTG.
But it does not work with some routers - PRTG gets no response when reading "isdnBearerOperStatus". All gateway are configured in a very similar way.
Monitoring ISDN status using "isdnLapdOperStatus" works OK on all routers/gateways.
Do you know how to troubleshoot SNMP?
Regards
Frantisek Opravil
