Switchport Counters - Take two

rwebb at ropeguru.com rwebb at ropeguru.com
Thu Mar 27 16:51:40 UTC 2014

Apologies to everyone for the original email with no subject. I am 
having some senior email moments today.


So I certainly admit I am a basic networking guy and in the past have 
not had to get into the nitty gritty of port statistics.

I am trying to understand some statistics off a switch port in a Nexus 

All TX and RX counters look normal except on the TX side, I am showing 
1107597 input discards. Last clearing of show counters is 1d8h ago.

I have it in my mind that this particular counter is dropping packets 
coming in from another port inside the switch that are to be 
transmitted out to the end server.

So lets say the interface I am looking at is port 2 on the switch. So 
server 1 sends a packet to port 1 on the switch. That packet then 
traverses to backplane, or inside the same ASIC, to port 2 on the 
switch. It is then dropped and not transmitted out to server 2.

Is the scenario I just presented correct? Not looking for the reason 
in this email, just that my logical understanding is correct.


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