Keep time-sensitive traffic on time when a network fails
Fail a network path and watch the real LinkShift engine keep the session going. Both paths are software-emulated on one PC (Wi-Fi-like and cellular-like delay and speed), not real radios.
Start a session
Settings for this scenario
You are watching. Live control needs a pass from the presenter: they can show you a QR code. Meanwhile, the Evidence tab has every recorded result.
The two paths
Each fault changes only the emulated path inside the sandbox.Moving markers show each path's measured throughput in the data direction (one marker per 5 Mbit/s). They illustrate the rate; they are not individual captured packets.
Video-like messages: on time or missed
Share of messages sent in each quarter second that arrived within 150 ms, arrived late, or never arrived. Vertical lines mark actions.
Show as table
Traffic on each path
Bytes on each emulated link in the data direction, including tunnel overhead and copies (Mbit/s, averaged over 1 s).
Show as table
More measurements: delay, TCP, engine view
One-way delay of the video-like flow
Median and 95th percentile per quarter second (ms). The line at 150 ms is the deadline.
TCP received
Application bytes received per second (Mbit/s), checked byte by byte against the sender's known stream.
Measured evidence
Recorded results from the formal evaluations, run on emulated paths on one PC with the plan and thresholds fixed before the runs. Every number shows its source.
Strengths, with context
Where upstream does better
Compare engines, condition by condition
RECORDED · formal runsNumbers as a table
Replay recorded runs side by side
RECORDED · formal runsEach run is the median run of its engine for this condition (by longest interruption) unless it says "worst". The shaded band is the fault window.
Run identities
Formal acceptance gates (Amendment 13)
Gate G3 in detail: two readings of one rule
How the project got here
The poster describes v22b from October 2026. Its numbers come from Amendments 10 and 11 and are not LS25 results. Choose "Amendment 11" in the comparison above to see that evaluation.
Data sources and file fingerprints
How it works
Apps send normal traffic. LinkShift carries it over every available network inside one encrypted connection and decides, packet by packet, which path can still deliver in time.
Architecture
Illustration, not a measurement
Tip: use full screen and turn the phone sideways for a larger view.
- AppsUnchanged; they see an ordinary network interface.
- TUNVirtual interface that hands the apps' packets to the client.
- LinkShift clientmqvpn + XQUIC with the LinkShift changes: picks a path for each packet, copies or drops time-sensitive ones.
- LinkShift gatewayChecks the key, assigns the tunnel address, schedules downloads with the same logic.
- DestinationThe service the apps talk to.
Built on open source
- mqvpn: an open-source multipath VPN. One QUIC connection carries IP packets (MASQUE CONNECT-IP, RFC 9484) as QUIC datagrams (RFC 9221) over several paths (multipath QUIC).
- XQUIC: the QUIC library inside mqvpn, with TLS 1.3 (BoringSSL), BBRv2 congestion control per path and a lowest-delay (MinRTT) scheduler.
- LinkShift is a set of changes inside mqvpn and XQUIC, compared against unmodified upstream releases. It is not rebased on v0.19.2; v0.19.2 is a comparator.
Default behaviour
- The path with the lowest measured delay carries traffic. There is no Wi-Fi preference and no cost awareness: if cellular were faster, it would be used.
- Two paths were evaluated; the code supports up to eight. Paths can come and go while running; an interface that returns, even with a new address, is added again.
- Priority applies to one marked UDP port (5000 in all tests); other traffic is ordinary.
What LinkShift adds, and where each idea comes from
Questions people ask
Limits and security
What has not been shown yet matters as much as what has.
The three limits to know first
Security: tested
Security: not tested yet
Design
Full list of known limits
Source documents
Operator console
Only reachable on the private address. Judges never see this page.
Sign in
Judge control pass
A pass works once, on one device, and ends after its time. Creating a new pass cancels the previous one.
Visitor QR (view only)
Offline pack for your laptop
Recorded video, evidence PDF, guides and source excerpts. They are recordings and copies, not live data. Download each file, then compare its SHA-256 (PowerShell: Get-FileHash FILE).
Show the code (private, for a judge's question)
Exact code of the frozen LS25 build, read from its git commits. Shown on this screen only; never on the public address.