A SpeedFusion tunnel joins two Peplink devices — a remote site and a hub (another router or a FusionHub). You build it once on each end from the PepVPN & SpeedFusion page in the local web UI. Here is every field on the SpeedFusion VPN profile and what it does.
Before you start
You need both units’ IDs (usually the device name) and a shared secret, and one end must know the other’s public address. SpeedFusion is a two-sided tunnel — the settings below are entered on each device.
Add a profile: PepVPN & SpeedFusion → New Profile
- Name — a label for the tunnel (e.g. HQ Hub).
- Enable — turn the profile on.
- Encryption — 256-bit AES (recommended) or Off. Keys are renegotiated automatically at random intervals.
- Authentication — Remote ID / Pre-shared Key: enter the remote unit’s ID and a shared key. The ID and key must match on both ends.
- NAT Mode — enable when the peer sits behind NAT.
- Remote IP Address / Host Names (optional) — the peer’s public address. If you leave it blank here, the remote unit must have your address filled in — at least one side has to be reachable.
- Cost — a routing metric; lower-cost profiles are preferred when more than one path exists.
- Data Port — Auto (recommended) or Custom, to steer the tunnel through a specific port for firewall traversal.
- Bandwidth Limit — optionally cap the tunnel’s throughput.
The performance options (the part that matters)
These four toggles are what turn a plain VPN into SpeedFusion. Pick per profile based on the links and the traffic:
- SpeedFusion Boost — sustains high throughput across lossy, unpredictable, high-latency links (bonded cellular, LEO satellite / Starlink) by preventing slower links from dragging down the faster ones. Supported on all models.
- TCP Ramp Up — accelerates how quickly TCP reaches full speed over high-latency SpeedFusion connections.
- WAN Smoothing — duplicates packets across multiple links so loss/jitter on any one link is invisible. Best for real-time (VoIP, live video, telemedicine); it trades bandwidth for stability. Levels Off → Maximum.
- Forward Error Correction (FEC) — reconstructs lost packets without retransmission, repairing lossy links with far less overhead than Smoothing.
Smoothing vs FEC vs Boost — which one?
WAN Smoothing = zero-loss real-time, at a bandwidth cost. FEC = repair a lossy link cheaply. Boost = keep total throughput high when links are lossy and high-latency. They can be combined; start with Boost for bonded Starlink/cellular and add Smoothing only for the real-time apps that need it.
Buffering & fragmentation
- Receive Buffer — milliseconds of buffer to absorb jitter and packet reordering across dissimilar links (e.g. Starlink at 50–60 ms bonded with LTE at ~100 ms). More buffer = smoother but slightly more delay.
- Packet Fragmentation — Always (default) or Use DF Flag to honor the don’t-fragment bit.
Field note
A profile alone doesn’t send traffic through the tunnel — you still have to steer traffic into it with outbound policy. And remember SpeedFusion is perpetual and built into the device; it’s not SpeedFusion Connect (SFC), Peplink’s hosted public service. Want the concepts first? See SpeedFusion 101.