C9410 Input Queue buffer SIze Change

[GWON GEON HO]

sh platform hardware iomd 1/0 qos port 1 ingress queue stats

DATA Port:1 Drop Counters

-------------------------------                    

Queue Drop-TH0    Drop-TH1    Drop-TH2    SBufDrop    QebDrop

----- ----------- ----------- ----------- ----------- -----------

Drop occurred in ingress queue status after C9410 deployment.

Is it possible to change the C9410 input queue size?

th

    0           0           0           0           0           0

    1           0           0   119300479           0           0

C9410 

[MHM Cisco World]

Check this

https://www.cisco.com/c/en/us/support/docs/switches/catalyst-9600-series-switches/220491-understand-output-drops-on-high-speed-in.html

MHM

[Joseph W. Doherty]

An excellent reference for dealing with egress drops.  Again, don't know if any settings can be applied explicitly or also make implicit changes to ingress when applied for egress.

@GWON GEON HO have you made any QoS configuration changes or are you running using defaults?

Also, what cards are being used, and if different line cards, which is being used for the OP interface stats?

[Joseph W. Doherty]

Good question, as off the top of my head, I don't know for that platform.  Often, switches don't offer much support for ingress queues because its cause usually is due to ASIC or fabric channel oversubscription.  I.e. reduction or elimination of the oversubscription is the usual fix.

Sometimes, at the hardware level, solution can be as simple as redistribution of port connections.

Ethernet flow might be an option, but not one I recommend.

Where ingress queuing supports management options, they trend to be very limited, and it's very easy to trade one problem for another, so also I wouldn't recommend.

[Joseph W. Doherty]

BTW, I might add two notes.

First, do you believe those ingress drops are very adverse to the ingress traffic?  At the moment, have no idea what the drop percentage is or the drop pattern.

Second, although many consider zero drops the ideal, the opposite can be true.  Zero drops may be an indication of underutilized bandwidth.  Or, might be due to excessive queuing, which can make for excessive queuing latency.