i'm facing an issue with quality of service (srr-queuing).
i have a cisco ws-c3560X and i have different VLANs on it, i have one VLAN who support video encoders. i want to fix priority on the video VLAN and make sure the stream to pass trough the uplink in priority.
so i made a qos vlan-based, i catch the flow and i mark it to dscp 40, then by default, the dscp 40 use the queue 1 for output, and it works well i can verify it with a "show mls qos inter gi1/4 statistic"
the flow is bigg because we have 4 stream at 20Mbps (more or less) so i configured a shaping on the egress side with this command:
srr-queue bandwidth share 85 5 5 5
srr-queue bandwidth shape 85 0 0 0
mls qos trust dscp
so i reserve 85% of bandwidth to queue 1 in case of congestion. Am i ok for the moment???
then, i looked the stream and it have a lot of drop, after revision, i saw a lot of dropped in the "output queue drop" corresponding to the first queue, first threshold.
i wanted to adapt the buffers and threshold by reading and following the cisco recommandations (i guess)
i did that :
i reserve buffer for queue 1 (the same as the srr queue shaping)