Hi to all,
Reading through the CCO document "Catalyst 3850: Troubleshooting Output drops" I came across the command qos queue-softmax-multiplier, by default in latest IOS XE3.6/3.7 is set to a value of 100 which corresponds to 1200 soft buffers per each gigabit port with no QoS enabled.
Those 1200 soft buffers are distributed in 2 queues
The value of the command qos queue-softmax-multiplier could be increased to a max of 1200...
If I configure it as 200 means a total of 2400 soft buffers per Gigabit port
since it's configured globally each Gigabit port "receive" new values and I was wondering where those soft buffers come from?
A global shared pool? What happens when you increase it on all port? is there a chance that this will create buffer availability problem since by default is very low?
Thanks for any suggestion
Old post, but exactly what I am experiencing. I get a random drop as seen in XMIT-ERR and OUTPUTDISCARDS, which are always equal in number, always.
UDP packets that are trying (buffered or queued) egress the port will drop catastrophically. No Ack/Nack UDP, so broken processes show up (on hosts).
Someone, somewhere, I hope; can concisely explain how to fix? QOS or softmax multiplier?
searching for a fix...