---
title: WindowsNetworkDiscards
---

## Meaning

Discarded inbound and outbound packets make up more than the configured share
of all packets on an interface for 15 minutes. The default
`networkDiscardRatioThreshold` is 1 percent. The ratio divides the discard rates
(`windows:net_received_discarded:rate` plus `windows:net_outbound_discarded:rate`)
by the packet rates (`windows:net_received_packets:rate` plus
`windows:net_sent_packets:rate`). Discards count packets dropped without a packet
error, such as buffer exhaustion. Interfaces that carry no packets produce no
sample and cannot alert. The alert keeps firing for `keepFiringFor` after the
ratio drops below the threshold.

## Impact

Dropped packets can cause retransmissions, reduced throughput, and application
timeouts. Some drops may be expected under a deliberate traffic policy.

## Diagnosis

1. Inspect `windows:net_received_discarded:rate` and
   `windows:net_outbound_discarded:rate` to identify the direction and affected
   `nic`, and compare them with the packet rate recordings to see whether a low
   packet rate inflates the ratio.
2. Compare traffic, directional utilization ratios, and
   `windows_net_output_queue_length_packets` with the normal baseline.
3. Inspect `Get-NetAdapterStatistics`, switch-port drops, adapter buffers,
   virtual switch counters, and network QoS policies.
4. Correlate drops with CPU pressure, traffic bursts, hypervisor contention, and
   application failures. An unknown or zero bandwidth estimate produces no
   utilization sample and should not be interpreted as zero traffic.

## Mitigation

Relieve congestion, distribute traffic, or add bandwidth. Correct buffer, driver,
or virtual switch problems when evidence identifies them. Review intentional
drop policies with the network owner before raising
`networkDiscardRatioThreshold`. Confirm discard rates and application
retransmissions return to the expected baseline.