hi all,
i'm facing an issue with quality of service (srr-queuing).
i explain:
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:
bandwidth 100000
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)
mls qos queue-set output 1 buffers 85 5 5 5
and i adapt the threshold for queue 1 too
mls qos queue-set output 1 threshold 1 400 400 100 400
to be sure :
Queueset: 1
Queue : 1 2 3 4
----------------------------------------------
buffers : 85 5 5 5
threshold1: 400 200 100 100
threshold2: 400 200 100 100
reserved : 100 50 50 50
maximum : 400 400 400 400
so i thinked i was good, but nothing do, i loose 1 packet over 2, and i don't know why, for more detail, the stream who's working for now is only 12Mbps and no congestion over the link.
do you see what's wrong??
do you need other explanation?
i was thinking about reserved bandwidth, is it good as i made? i have to reduce the other reserved threshold on other queues?
any help can be valuable (and sorry for my bad english)
thanks
Best Regards
