Network & Infrastructure / IPv6, TCP & Transport Engineering
Bufferbloat: high throughput with unacceptable interactive latency
A saturated circuit achieves expected goodput while voice and interactive sessions become unusable. Large unmanaged queues can add substantial delay without showing persistent packet loss.
Environment and inputs: Dual-stack routed networks and transport endpoints; validate the complete path and the active operating-system version. Diagnostic/design example; not tested on production equipment.
Collect the evidence
Measure loaded and unloaded latency, egress queue depth, drop/mark behavior and circuit shaping rate. Include provider handoff speed versus the actual contracted bottleneck.
Explain the result
A fast local port can feed a slower downstream service, moving the queue outside the visible device. More buffering can hide drops while making waiting time worse.
Plan the fix
Place shaping and supported active queue management at the measured bottleneck and allocate classes according to service needs. Avoid shrinking every queue without considering burst absorption.
Check the result and rollback
Compare interactive latency and bulk goodput under mixed load and failover. Restore prior settings if useful throughput collapses or the queue merely shifts to an unobservable downstream boundary.