qos queue-softmax-multiplier 1200

[tedauction]

Hello, I recently had a Cisco tech support session on a 3850 switch re output drops on an interface.

One of the first things he did was run the command 'qos queue-softmax-multiplier 1200' to increase the soft buffers to the maximum.

My question, is why would you not do this on all new switches i.e. is there some drawback to increasing the buffers to the maximum.

Thank you.

[Joseph W. Doherty · Accepted solution]

Well, if you queue rather than drop, you often add latency to your packets.

Additionally, depending on the architecture of the switch, increasing the number of buffers a port may grab can preclude other ports from obtaining buffers, including for even more "important" traffic.