Congestion causing packet loss detected

The path to this hop exhibits packet loss consistent with a congested network.

Recommended action

  • Take steps to avoid congestion, such as reducing traffic, increasing capacity or adjusting routing tables.
  • Ensure NIC cards are running latest version of drivers. Some GigE cards are less likely to congest when running newer driver versions.

Detailed explanation

In Delivery monitoring, packets are considered to be lost if they are not acknowledged (reply packets are not received back) within an internal timeout period. Either the acknowledgements to the test packets are exceedingly slow to arrive back from this hop, or packets are being dropped. A router generally drops packets due to congestion; either because its buffer space for queuing packets has filled up, or because it has been set up for rate limiting. Rate limiting is when a traffic-shaping router or server is set up to drop packets on the basis of total throughput.

Possible secondary messages

  • "Likely due to excessive traffic"
  • "May be due to an overloaded router"

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