# Cost-Based Parent Selection: Hysteresis Stability Test
#
# Topology (explicit 4-node diamond, symmetric):
#
#    n01 (root)
#    /       \
#   wifi     wifi
#   /         \
#  n02        n03
#   \        /
#   wifi    wifi
#     \   /
#      n04  (test subject)
#
# All links are WiFi-like with similar characteristics. Aggressive
# netem mutation shifts link qualities every 10-20s, but the changes
# stay within the 20% hysteresis band. n04 should pick one parent
# and mostly stick with it — flapping indicates insufficient hysteresis.
#
# Validation: n04 should switch parent at most 5 times. This is now the
# max_parent_switches assertion below, scoped to n04. It previously
# existed only as this comment and was checked by nothing, so the
# scenario could not fail on it.
#
# The threshold of 5 is the one this comment always named, kept
# deliberately rather than re-derived. What the number is worth, from 11
# completed archived runs of this scenario: n04 was 1 or 2 every time and
# never reached 3, while the mesh-wide total ranged 3 to 6. Two
# consequences worth knowing before trusting a green result here.
#
# First, 5 is a long way above anything observed, so this catches only
# near-pathological reparenting. The daemon's own 30s parent hold-down
# caps non-mandatory switches at roughly 6 per 180s run, so the band
# where this can fail is narrow. A hysteresis regression that added two
# or three switches would pass.
#
# Second, the count spans the container's whole life, not just the
# mutation phase: in the archived runs nearly every n04 switch lands in
# the first 100ms during initial tree formation, before the first netem
# mutation fires. So this number is dominated by convergence transients
# rather than by the hysteresis behaviour the scenario is named for.
#
# Tightening to 3 would make it a real detector against the observed
# distribution. That is a change to the stated criterion rather than a
# fix, so it is left as a decision rather than taken here.

scenario:
  name: "cost-stability"
  seed: 42
  duration_secs: 180

topology:
  algorithm: explicit
  num_nodes: 4
  params:
    adjacency:
      - [n01, n02]
      - [n01, n03]
      - [n02, n04]
      - [n03, n04]
  subnet: "172.20.0.0/24"
  ip_start: 10

netem:
  enabled: true
  default_policy:
    # WiFi baseline
    delay_ms: [5, 20]
    jitter_ms: [2, 5]
    loss_pct: [1, 3]
  mutation:
    interval_secs: {min: 10, max: 20}
    fraction: 1.0
    policies:
      slightly_better:
        delay_ms: [3, 8]
        jitter_ms: [1, 3]
        loss_pct: [0, 1]
      slightly_worse:
        delay_ms: [15, 25]
        jitter_ms: [3, 8]
        loss_pct: [2, 4]

link_flaps:
  enabled: false

traffic:
  enabled: true
  max_concurrent: 2
  interval_secs: {min: 15, max: 30}
  duration_secs: {min: 5, max: 15}
  parallel_streams: 2

assertions:
  max_parent_switches:
    node: n04
    max_total: 5

logging:
  rust_log: "info"
  output_dir: "./sim-results"