We run a test environment with A5c and C5x, 2.5.3 SW version. And we have met a QoS configuration problem. We have configured the ACL on A5c, marking ICMP traffic with DSCP = 63 and TC = 7. Also, we have configured the Maintenance -> Application Prioritization function enabled and set ICMP with highest priority.
The test environment is very simple:
PC — C5x — A5c — Router — Internet
But when we try to measure latency via PING command (standart 32 bytes) with running speedtest at the same time to fill the bandwidth we can still see, that the PING latency with speedtest running is still 3-4 times higher:
All PING commands running on PC, average latency
to C5x, permanently = 1 ms
to Router, during no other traffic = 14 ms
to Router, during Speedtest DL, no ACL config = 523 ms
to Router, during Speedtest UL, no ACL config = 15 ms
to Router, during Speedtest DL, ACL and Application Prioritization config = 65 ms
to Router, during Speedtest UL, ACL and Application Prioritization config = 18 ms
So, we can see the influence of QoS configuration on A5c, but it’s not ideal.
Also, there is a question for default values of TC and DSCP for unmarked traffic - is it “0” or some other value ?
Thank you in advance!