Some port channels are not correctly associated with their corresponding physical interfaces in Spectrum

Products

• DX NetOps

Issue/Introduction

For a Cisco Catalyst 9500 cluster with two chassis acting as one logical entity, some port channels are not correctly associated with their corresponding physical interfaces. The problematic port channel consists of two physical interfaces, each from a different chassis, as correctly modeled for other devices of the same type e.g.  (1/0/1 and 2/0/1 for Po1). On the device in question, the port channel is only shown for the port on chassis 2.  The problematic port channels  are not associated with any physical interfaces.  The issue persists even after re-modeling the device. It could be reproduced with sims.

Environment

All Spectrum versions with Cisco Catalyst clusters.

Cause

Comparing the 2 sapwalks shows the problem. For forming relations we depend on ifStackStatus OID values. 

From the sapwalk of the working device we see the 2 required entries:

ifStackStatus.116.3           , Integer     , RC , rowstatus(1)
ifStackStatus.116.55          , Integer     , RC , rowstatus(1)

not working device shows only 1 entry:

ifStackStatus.116.55          , Integer     , RC , rowstatus(1)

 

the interface index 116 Po1 has two lower layers 3, Twe1/0/1 and 55 Twe2/0/), 
whereas on the problematic device shows the interface index 116, Po1 has only one lower layer 55, Twe2/0/1.

For this reason, Spectrum does not show the relation to Twe1/0/1 for second device.

Resolution

This indicates it is either device MIB problem or connections doesn't exist at device side.  Either way Spectrum is modeling it correctly based on the info provided in the mib.  This needs to be addressed by the vendor.

As a workaround,  manually create the HASPART association between parent and child models and the port channel will correctly shown beneath the interface.