Input Discard

[Robo123]

Hi Team,

I am observing input discard,CRC,and input errors on my nexus(Nexus 5696 ) interface.

sh int et2/5

MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec
reliability 255/255, txload 5/255, rxload 1/255

0 runts 0 giants 15098 CRC 0 no buffer
15098 input error 0 short frame 0 overrun 0 underrun 0 ignored
0 watchdog 0 bad etype drop 0 bad proto drop 0 if down drop
0 input with dribble 14335 input discard
0 Rx pause

The other end of the device is connected to 4500x chassi where not observing any interface errors.

I had changed Transceiver and Cable but still observing errors.

Can any one help to resolve the issue.

[Reza Sharifi]

Hi,

Do you see the same issue if you connect the cable to a different port e.g e2/6?

HTH

[Robo123]

Not observing .

But observed Rx stomped packet count is incrementing.

RX_PKT_CRC_NOT_STOMPED | 12888244 | 12888238 | 3
RX_PKT_CRC_STOMPED | 0 | 0 | 0

[Reza Sharifi]

Can you provide the config for the port with issue?

sh run int tex/x

sh int tex/x

Is jumbo frame enabled on the switch?

HTH

[hlumca]

I am seeing a similar issue on my 5672UP. The input discard is happening on e1/7 for me. I found this article which provided some insight.

https://www.cisco.com/c/en/us/support/docs/switches/nexus-6000-series-switches/200401-Nexus-5600-6000-Understanding-and-Troub.html

Running the command "sh hard internal bigsur all-ports" shows that e1/7 is associated with ASIC 1.

Running the command "sh plat soft qd info counters voq asic-num 1" displays

+----------+------------------------------+------------------------+-----------+
| port| TRANSMIT| TAIL DROP| HEAD DROP|
+----------+------------------------------+------------------------+-----------+
SUP_HI
  QUEUE-0 169753328 31028747 0
SUP_LO
  QUEUE-0 17 0 0
+----------+------------------------------+------------------------+-----------+

My question is: What is SUP_HI?

[hlumca]

I still do not know what SUP_HI is but I managed to fix my Input Discard issue. I had my gateway configured using

vrf context management
  ip route 0.0.0.0/0 <gateway>

I replaced this with routes to specific subnets

vrf context management
  ip route <subnet1> <gateway>
  ip route <subnet2> <gateway>

[Sergiu.Daniluk]

SUP_HI and SUP_LO are the two interfaces connecting the Nexus 5k/6k CPU to the UPC (you can see them on the down-right UPC)

Stay safe,

Sergiu