Smarts IP: LAPD Interface status shown incorrectly for Cisco ISR Router

Products

• VMware Smart Assurance

Issue/Introduction

Symptoms:


Smarts shows OperStatus for interface instrumented by Interface_FaultLAPDData to be UNKNOWN. SNMP walk confirms OID 1.3.6.1.2.1.10.20.1.3.4.1.2 (isdnLapdOperStatus) is present on the device but the correct status is not reflected in Smarts.

Environment

VMware Smart Assurance - SMARTS

Cause

During device discovery, Smarts executes ic-clear-interface-layering.asl file for creating dynamic instrumentation for interfaces with iftype "LAPD" and performs index parsing and updates TopologyUpdateInfo. During this stage, it picked up wrong index. 

Due to which Smarts was continuously polling wrong index (say index 0) for interface index 3 and 4 (numeric values taken as an example).
Hence the device was consistently returning noSuchInstance as response during polling, causing Smarts to mark interface status as Unknown.

Resolution

Follow the below steps to implement the modified ic-clear-interface-layering.asl file as workaround:
1) Copy the attached ic-clear-interface-layering.asl file & place it in <Base Directory>/IP/smarts/local/rules/discovery.
2) Rediscover the device.
The correct/expected interface OperStatus should be updated post the first polling cycle after the discovery completes.

Additional Information

This issue was reported for Smarts IP 9.4.1.x version, workaround in this article can be implemented in same version.
This fix is yet to be added to upcoming patch releases of Smarts IP suite as of June 2018. Please contact Dell EMC Technical Support if a fix is required for IP versions other than 9.4.1.