Small packet congestion detected

Message ID
Small packet congestion detected.
Congestion caused by densely arriving packet headers has been detected.
  1. Identify switches, gateways, etc., associated with the hop where the loss first appears.
  2. Assess the impact of the problem, i.e., determine whether you expect to have dense small packet bursts or streams across that segment.
  3. If possible, perform intrusive flooding tests across the segment to isolate the device or software responsible.
  4. Upgrade hardware or software of the limiting device and/or turn off the software feature that is responsible.
This diagnostic involves a specific form of small packet loss attributed to devices that have difficulty handling packet headers arriving too close together. Unlike regular congestion which is sensitive to the amount of data, not the number of headers, this header congestion condition affects applications specific to small packets, such as real-time voice and video, but only when there are many densely aggregated streams. A single voice stream is unlikely to generate this condition. The NIC, or some other device in the path, is unable to process headers at sufficiently high rates, and packet loss/corruption is the consequence. Small packet congestion is distinct from regular congestion, which is attributed large packets filling queues/buffers at store-forward devices, e.g., routers or receiving NICs.
Possible secondary messages
  • Limiting network processor or other small packet sensitive constriction detected
  • May impact real-time traffic such as voice
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