Multi-Modem Bonding with Belabox
Multi-Modem Bonding
Bonding means: using multiple internet connections at once to combine bandwidth and become resistant to any single connection failing. For mobile IRL streams it's the difference between "my stream keeps dropping" and "runs like butter".
How does bonding work?
Your Belabox or LiveU has several slots for 4G/5G modems (typically 2–8). The system:
- Splits your video stream into small SRTLA packets
- Sends the packets out in parallel across all modems
- The FizzyPeak server receives the packets and reconstructs the original stream in the correct order
- If a modem briefly fails → the others take over automatically
- If a modem slows down → the system reduces its share of packets
This is different from load balancing: bonding uses all connections at once for the same stream, not parallel streams.
What do I need?
Hardware options
Belabox (recommended, DIY or pre-built)
- 2–4 SIM slots
- Runs on a Raspberry Pi 4 or dedicated hardware
- Open-source software
- Price: €300–600 pre-built, €150 DIY
LiveU Solo
- 2–4 modems built in
- Professional-grade, €2000+
- Easy plug-and-play
Moblin (iOS app)
- Uses iPhone LTE + WiFi in parallel
- Free, software-only bonding
- Limited to 2 connections
IRL Pro (iOS/Android)
- Similar to Moblin, but with more configuration
- Free for basic, Pro $5/mo for bonding
SIM cards
Recommendation: 2–4 different providers. If you use Telekom + Vodafone + O2 + 1&1 and one goes down, the other three are on different cell networks.
Data volume: 50–100 GB/month per SIM (IRL streams pull ~3 GB/hour).
Prepaid plans are ideal — no contracts, switchable anytime. Popular in Germany:
- Aldi Talk / Lidl Connect (O2 network)
- Freenet Funk (Vodafone)
- High / Premium-SIM (Telekom)
How do I configure Belabox for FizzyPeak?
Step 1: Insert the SIMs
Put each SIM into a free slot — Belabox detects them automatically on boot. In the web UI (http://belabox.local or 10.42.0.1), check that all modems show as "Connected".
Step 2: Set up the SRTLA destination
In the Belabox UI: Settings → Destination
- Protocol: SRTLA
- URL: your FizzyPeak SRT URL (copy it from the dashboard)
- Latency: 2000 ms (proven for bonding — allows retransmits across multiple modems)
Step 3: Enable bonding mode
- The default is "Group Multiplexing" (all modems active)
- Alternative: "Failover" (primary only, others only on failure) — less bandwidth but more stable
Step 4: Start
Click Start Stream in the Belabox UI. In the dashboard under IRL tab → Stream Health you can see live:
- Combined bitrate (all modems aggregated)
- Per-modem status (green = active, yellow = weak, red = off)
How much bitrate can I push?
With a good connection and 4 modems at 15 Mbps LTE each, realistic numbers are:
- Combined: 20–30 Mbps effective (SRTLA overhead eats 20–30%)
- For a 1080p60 stream: 8–10 Mbps (uses only ~40% of your bandwidth — healthy)
Don't max out the bitrate! A 1080p60 stream at 6–8 Mbps looks better than one at 15 Mbps with congestion.
Tips from the field
- Antenna position is everything. Flat antennas on top of the backpack > rod antennas on the sides
- Batteries — bonding setups are power-hungry; expect 4–8 hours of runtime from a 20000 mAh bank
- When riding a motorcycle: 2 modems in the back, 2 in the front (the airstream interferes with antennas)
- Weather: rain attenuates the 4G signal. In heavy rain, drop the bitrate to 4 Mbps
What happens if all modems fail?
NOALBS automatically switches to your BRB scene. Your BRB video loops, and Twitch keeps seeing the stream as active. As soon as at least one modem comes back above the threshold, NOALBS switches back to live.
In short
Bonding is the core feature for professional IRL streams. With 2–4 modems on different networks you'll have practically no more connection drops — and FizzyPeak handles the rest server-side.
Noch Fragen? Öffne das Dashboard oder schreib im Discord #support.