YueGuobin eda2d640ab
docs: packet filters — deepen the per-filter guide with mechanism notes
Follow-up enrichments to the Per-filter guide, one per filter, each
answering the question a reader asks right after "what does it do":

- window_drop: explicit recurrence formula ([Start + k*Period, +Outage),
  duty cycle) and ASCII timelines of the three forms (one-shot /
  recurring / jittered); Chance spelled out as an independent per-packet
  draw gated to the window; jitter explained as per-cycle re-draws that
  break phase-locking with protocol timers
- quota: transparent until the budget is consumed; Chance equals
  packet_loss in draw mathematics but runs in the eBPF classifier stage
  (no correlation parameter, outside seed, invisible to captures)
- limit: the phantom-loss symptom (throughput below the configured rate
  with rate+delay set = the 1000 default overflowing)
- seed: reproduction also requires the same traffic pattern (draws are
  consumed per arriving packet); one pinned realization is not the
  distribution — statistical conclusions need several seeds
- gemodel: scattered-vs-bursty timeline at the same 5% mean (fast
  retransmit vs RTO), and a parameter recipe (M and L -> r, p)
- reorder: the mechanism is queue-jumping on the netem delay queue —
  hence the delay requirement, the limit overflow interaction and the
  delay-bounded reorder depth
- rate: per-direction independent shaping (symmetric full duplex, no
  shared budget); asymmetric rates need in-guest netem
- duplicate: real-world prototype (802.11 ARQ retransmissions), example
  values with the correlation-collapse anchors (10/25 -> ~1.8%, 25/25
  -> ~16.7%)
2026-10-15 01:08:53 +08:00
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