Assumer I have a new router device of Cisco with 2 ports ethernet 10/100/1000. As everybody know that QoS based on DSCP field in IPv4 header to have difference policy for difference class. I start configuring this router. Example, with traffic in best-effort mode (DSCP = 0), the speed should be 15Mbps, with traffic in AF32 class (DSCP=28), the speed should be 35Mbps and with traffic in EF class (DSCP=46), the speed should be 50Mbps.

The question is: 1. How can test/measure exactly a speed that I configured? 2. How about for another specification like: latency, jiter?

Thank you!

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    – Ron Maupin
    Feb 19, 2018 at 5:28

1 Answer 1


You can attach cisco switch with two PCs behind the router. Dot1q trunking can be used with 1 vlan per PC for traffic generation and second one for SLA probes. The router must be used for inter-vlan routing, traffic shaping also should be configured here. IPERF/JPERF can be used for traffic generation.

On both switch ports you can mark the traffic with specific DSCP value, which needs to be used later in the policy.

Speed can be easily measured with IPERF:

  • UDP: you can send specific amount of traffic e.g 10mbit/s, and measure the packet loss.

  • TCP: Just start server/client and you will get the best possible value achieved by the TCP protocol.

Latency can be extracted from iperf test, but I'd recommend adding SLA probes via some external software like this one

  • I have used iperf3 before for testing speed. I have used --dscp option for marking DSCP value, too. But the problem is packet generated by iperf3 tool just have fixed DSCP value, so I want testing with "mixed" traffic, it means different packet with different DSCP value concurrent.
    – Yuri
    Jun 26, 2017 at 6:53
  • That's why I said that you can use the switch for marking. On inbound direction you can use policy with different classes, matching based on access lists: 1 class can be UDP session, 1 flow can be a TCP session and 3-rd one can be ICMP for example Jun 26, 2017 at 9:05

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