show cable-diagnostics tdr remote pair discrepancy

[briankk1582]

Hi everyone,

I currently have a 9300 switch stack implementing a PoE solution, and we're running cables through our plenum but are running into an issue.

Our electricians have run the cables and terminated it straight-through according to tests using a Fluke DTX1800. However, after running a tdr test on the cable, the results were showing a crossover pinout where the local pair A was terminating to remote pair B, and vice versa for the remaining pairs.

Just for kicks, I reversed the pinout myself into a crossover pattern, but the tdr test output shows no change.

I'm running version 17.7.1. Has anybody encountered this issue before?

Be well,

Brian

[Reza Sharifi]

Hi Brian,

If you are planning on connecting end devices to that switch, the cabling needs to be straight and not crossed.

HTH

[briankk1582]

The devices work fine whether they're connected via straight or crossed, most modern NICs are capable of operating either or. The issue I'm having is that the show cable tdr interf command is not showing the correct pinout on the remote pair column when I pin them out either way. When I run them as crossover or pinout, the column shows them as crossover and there's no change.

I have a feeling this may be a cosmetic bug and I'm seeing a variety of inconsistencies throughout the 9300 stack but I can't find any bugs or notices stating as such.

Will open TAC case and let you know what they say.

[Leo Laohoo]

Post the complete output to the command "sh cable tdr interface <PORT>".