Rate-limiting behavior detected

The network is exhibiting behavior, including packet loss, which corresponds to a mid-path device limiting the rate of data transfer.

Recommended action

  • If rate limiting is not desired, turn off rate-limiting queue settings within network devices (e.g. CAR).
  • If rate limiting is desired, consider implementing a traffic shaper which will reduce overall throughput by delaying packets, not dropping them.

Detailed explanation

Rate limiting is when a traffic-shaping router or server is set up to drop packets on the basis of total throughput, thereby limiting the rate of data transfer along the network path.

This behavior can, under some circumstances, appear very similar to a full/half-duplex conflict.

Rate limiting may inhibit the measurement of the path. It is possible to decrease the number of packets to a point where rate limiting is no longer triggered and measurements become possible. You can make adjustments to the number of packets sent in the advanced test setting "Packets per burst". Increasing this value improves resolution but also increases network load. Decreasing this value has the opposite effect.

Possible secondary messages

  • "May be a full/half-duplex conflict" Although rate-limiting behavior is more likely here, this condition should also be considered as a possibility.
  • "Re-running test with more packets per burst may confirm behavior" Rate-limiting behavior is sensitive to the number of packets being sent. Increasing the number of packets sent will more often trigger the rate limiting and help to confirm its presence.
  • "Appears to be a bucket type of mechanism associated with a low capacity link"
  • "Limiting affects high call load packets"

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