BeanheimNet

Valheim 1.0.x netcode improvements for the Beanheim dedicated server and its clients, with the telemetry to prove (or disprove) each one. One DLL, runs on the server and on clients. No ServerSync, no version lock: a client without it connects and gets vanilla behaviour, because nothing here changes the wire format.

The research behind it (decompiled 1.0.15 server assembly, prior-art survey, corrections to earlier assumptions) is in the profile repo at docs/networking.md.

What vanilla does, in one paragraph

Every ZDO update is sent reliable on one Steam lane. ZDOMan.SendZDOs keeps at most 10 KB in flight per peer (unacked bytes count), so throughput is 10 KB / round-trip-time — 68 KB/s at 150 ms — and Steam's send rate is pinned at 150 KB/s. The same limit applies to each client's uploads. Send order puts every building piece ahead of every creature, cart and drop. Owners write position on any exact change, so a bobbing or jittering object talks every frame, and ~95 % of relayed updates on this server were ambient fauna.

Features

Everything that is invisible to players ships on: F1, F2, F3, F4, F5, F6 and telemetry. The two that change what players see ship off: F8 Cleanup (deletes far-off floating junk) and F9 ItemMerge (merges nearby piles). Nothing here adds a version lock, so a player without the mod still connects; they simply keep vanilla behaviour on their side.

Toggles

Console: bnet stats | census | items | cleanup dryrun|run | reload | config (in-game console; the dedicated server binary never reads stdin, so on the server use the cfg instead: set one of [10. Triggers] Census / ItemReport / ItemCleanupOnce / Stats = true, it runs on the next reload (within 5 s) and resets itself to false).

Build and deploy

dotnet build BeanheimNet/BeanheimNet.csproj -c Release                          # build
dotnet build BeanheimNet/BeanheimNet.csproj -c Release -p:DeployToProfile=true  # + copy into the Gale profile

References resolve from the real game and Gale's BepInEx install; no binaries are committed. The profile's tools/vsync.sh diff then shows + BeanheimNet.dll; the server owner stops the server, runs apply, checks the RE-VERIFY block is all-zero, and restarts. Friends receive the DLL through the normal Gale profile sync.

Reading the numbers

• deferred = candidates that did not fit the window this round. Sustained non-zero at 2+ peers means the window is the wall. At ≤ 1 peer it is structurally 0 (nothing to relay).
• refused = rounds that sent nothing because the queue was above the window. High refused with high rtt is the 10 KB/RTT limit.
• app RTT ≫ rtt (Steam) = data is queueing behind other data (bufferbloat). Raise F3 before F1.
• throttled = F4 removals this interval (deferred by rate, not lost).
• frame avg 33.3ms on the server = vanilla's 30 fps cap; sched frames/served/budget-breaks appear once F2 is on.
• steam-status ok N not-ok N last <EResult> appears when Steam's connection-status call fails; without it F1 stays at vanilla for that peer and F3 cannot re-apply to live connections.
• Vanilla's own Connections N ZDOS:X sent:Y recv:Z line stays as the cross-check; both counters are meaningless at ≤ 1 peer.

Measuring a change

To attribute a change, turn a toggle off in the cfg (live; no restart), play ≥ 10 min, compare the stats lines, turn it back on. The vanilla baseline for Beanheim was recorded on 2026-09-21 (see the profile's docs/networking.md): a LAN client pinned at ~130 KB/s upload with thousands of updates deferred per 10 s, and a base arrival relayed at 40–60 KB/s with 160,000+ deferred.

Rollback

[1. General] Enabled = false (live) makes every patch behave like vanilla on its next call. Full removal: delete BepInEx/plugins/BeanheimNet/ locally, vsync.sh diff shows - BeanheimNet.dll, stop, apply, restart. Nothing persists in the world except F8 deletions, and only when Cleanup = true.

Fail-soft rules

Every private vanilla member is bound once at startup (Bindings.cs); a missing member disables the features that need it with a logged reason. Every patch body is wrapped: an exception logs once per minute and that call falls back to vanilla. The plugin refuses to install anything but telemetry if Smoothbrain Network, ValheimTune, NetworkPerformanceSystem, ReturnToSender, BetterNetworking or VBNetTweaks is loaded, and lists every other Harmony owner of the methods it touches at boot ([owners] lines).

Changelog

0.2.2 — 2026-09-22

• RelayThrottle: two new object classes. FloatingHz (default ∞/5/3) for floating objects that are neither items nor creatures (prefabs with a Floating component: logs, debris), which were unthrottled at any distance and the top uplink talker at a harbour; EffectHz (default 10/5/3) for networked sfx_/vfx_ prefabs (a sound that follows a bird). Floating objects use the item deadband.
• Deadband: a ship with nobody aboard gets its own deadband (MooredShipPosMeters 0.05, MooredShipRotDegrees 2); a ship with a player aboard, players and carts stay untouched. Ship.HasPlayerOnboard is bound once at startup; if it is missing only this part is skipped.
• Items: an item whose item data cannot be read (no data blob) is treated as valuable and never deleted, like enchanted, quality and gear items.
• Telemetry: the stats line gains frames >50ms N >100ms N and gc N heap N MB cpu N% (gen-0 collections in the interval, managed heap, process-wide CPU as a share of one core).
• Text: the Commands boot line names the 11 Triggers section; three leftover feature-key labels removed from a log line and two cfg descriptions.
• README rewritten: short overview, before/after numbers from a live two-player A/B, settings and stats-line details under Advanced, build notes removed; manifest description shortened.

0.2.1 — 2026-09-21

• cfg sections renamed to plain names (02 SendWindow, 03 Scheduler, 04 SteamTransport, 05 RelayThrottle, 06 Priority, 07 Deadband, 08 Telemetry, 09 Items, 10 ItemMerge, 11 Triggers); log tags match. Existing cfg files keep the old sections as orphans and the new ones start at defaults.
• Scheduler credit carries across slow frames (a peer is still served at most once per frame), so a CPU-bound server reaches the configured rate.
• README, comments and cfg text no longer refer to any particular installation.
• MinWindowBytes defaults to 32768.

0.2.0 — 2026-09-21

• Defaults: everything invisible to players is ON (window, scheduler, Steam rate, throttle, priority, deadbands, telemetry); Cleanup and ItemMerge stay OFF. A vanilla baseline was measured first.
• Client uplink throttle measures distance from the nearest loaded player, not just the owner; gentler rates (fish 6/3/2, creature ∞/10/5, item ∞/5/3).
• MinWindowBytes defaults to 16384.
• Unwrap ServerSync's BufferingSocket wrapper to reach the real Steam socket (server-side status, window sizing and per-connection rate apply were inert without it).
• Client-side item merge; hard rule that enchanted / quality / gear items are never deleted.
• ServerTargetFrameRate; cfg Triggers; Steam status and per-connection diagnostics on the stats lines.
• Thunderstore packaging (tools/package.sh).

0.1.0 — 2026-09-20

First build, against Valheim l-1.0.15 (network version 40), BepInEx 5.4.23.5, Harmony 2.9.