Step load CIR test

This test verifies that an Ethernet service QoS profile behaves as expected as the bit rate is increased. It is assumed that the service has a QoS profile with the CIR parameter as well as the maximum frame loss ratio, delay, and jitter values for conforming frames. For the generated stream the following parameters need to be specified: frame size, load frame size, the source and destination UDP port, DSCP value, and VLAN priority (p-bits).

Test procedure

The sender Test Agent starts by generates frames at a rate of 0.25 × CIR.

The receiver Test Agent measures received rate, loss, delay, and jitter on the stream. If the last three metrics are below the maximum frame thresholds, the test is repeated at a higher rate. In each step, the rate is increased by the Load step size parameter. This procedure is iterated until CIR is reached.

The test fails if any threshold (maximum frame loss ratio, delay, or jitter) is exceeded in any step.


The test conforms to ITU-T Y.1564 section 8.1.2, test A.2.



  • Sender: The sender interface.
  • Receiver: The receiver interface.
  • Load step size (Mbit/s): The amount by which the rate is increased in each step. No default.
  • Test duration (s): Duration of the test in seconds. Min: 5 s. Max: 60 s. Default: 20 s.
  • Wait for ready: Time to wait before starting the test. The purpose of inserting a wait is to allow all Test Agents time to come online and acquire good time sync. Min: 1 min. Max: 24 hours. Default: "Don't wait", i.e. zero wait time.

QoS profile

  • CIR (Mbit/s): Committed information rate. Min: 0.1 Mbit/s. Max: 10000 Mbit/s. No default.
  • Max frame loss (%): Maximum frame loss ratio for conforming packets. Min: 0%. Max: 100%. No default.
  • Max frame delay (ms): Maximum frame delay for conforming packets. Min: 0 ms. Max: 1000 ms. No default.
  • Max frame jitter (ms): Maximum frame jitter for conforming packets. Min: 0 ms. Max: 1000 ms. No default.

Traffic profile

  • Frame size (bytes): Ethernet frame size in bytes. Min: 64 bytes. Max: 1514 bytes. Default: 512 bytes.
  • Source UDP port: The source UDP port to use. Range: 1 ... 65535. Default: 5000.
  • Destination UDP port: The destination UDP port to use. Range: 1 ... 65535. Default: 5000.
  • DSCP: The Diffserv code point. Range: 0 ... 63. Default: 0.
  • VLAN priority (PCP): Priority bits in VLAN header. Min: 0. Max: 7. Default: 0.

Result metrics

  • Rate, loss, delay, jitter
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