Multicast IPTV vs OTT streaming: why you'll run both
There are two ways to put live TV on a screen: send one stream to many viewers across your own managed network (multicast IPTV), or send a separate adaptive stream to each viewer over the public internet (OTT unicast). New deployments increasingly build on OTT — it reaches any network and any device. But the many managed networks already running multicast keep it for good reason: for live at scale, nothing matches its efficiency, near-zero latency and guaranteed quality. The two aren't rivals — many operators pair them: multicast for live, unicast for the rest.
inext STBs and our IPTV app speak both — multicast on your managed network, OTT over the internet, on the same box. We support both because our clients use both.
Start here
It's about the network, not just the stream
The real difference isn't picture quality in the abstract — it's where the video travels. Multicast sends a single copy of each live channel through your managed network, and everyone tuned in shares it: 50,000 subscribers on one channel cost the same bandwidth as one. OTT instead opens a separate unicast stream for every viewer over the public internet, adapting the bitrate to each connection. One is built for efficiency and control on a network you own; the other for reach and flexibility on networks you don't.
Honestly, for a greenfield build OTT is now the default — most new deployments are unicast, and pure multicast IPTV is widely treated as legacy. But “legacy” doesn't mean bad: where a managed network already carries multicast, it delivers picture quality, near-zero latency and network efficiency that unicast still can't match for live at scale — so there's rarely a good reason to tear it down. That's why multicast stays widely deployed, usually in a hybrid: multicast for live linear, unicast for VOD, catch-up and time-shift. Each job on the transport that does it best.
Multicast IPTV
OTT unicast
How each works
Two transports for live video
Multicast IPTV
One stream, shared by every viewer, on your managed network
- One copy of each channel travels the network; viewers join it via IGMP
- Bandwidth stays flat no matter how many tune in
- Fixed bitrate and prioritized traffic — guaranteed, buffer-free quality
- Sub-second latency — ideal for live sports and national events
- Runs on a managed, multicast-enabled network over wired Ethernet — Wi-Fi can't carry it reliably
- Built for live linear; VOD and personalization still ride unicast
OTT unicast
A separate adaptive stream per viewer, over the public internet
- Each viewer gets their own stream from a CDN
- Adaptive bitrate (HLS/DASH) flexes to each connection's speed
- Reaches any network and any device — phones, laptops, Smart TVs, off-net
- Best-effort quality; latency is higher (low-latency HLS/DASH now ~2–5s)
- Bandwidth and CDN cost scale with every concurrent viewer
- Carries VOD, catch-up, nPVR and personalization natively
Side by side
How the two compare
| Multicast IPTV | OTT unicast | |
|---|---|---|
| Bandwidth at scale | Flat — one stream serves all | Linear — one stream per viewer |
| Network needed | Your managed network only | Any network, public internet |
| Reach | On-net set-top boxes | Any device, anywhere |
| Quality | Guaranteed, fixed bitrate | Best-effort, adaptive |
| Live latency | Sub-second | ~2–5s low-latency, up to 10–30s |
| Best for | Live linear, sports, big channels | VOD, catch-up, mobile, off-net |
| VOD & personalization | Needs unicast | Native |
| Cost shape | Network setup; flat at scale | CDN / egress; grows with viewers |
| QoS control | Full — you own the network | Limited — best-effort |
| Connection | Wired Ethernet — not Wi-Fi | Any link, Wi-Fi included |
| On inext boxes | One IPTV app plays both — multicast on-net, OTT off-net | |
Most platforms put live linear on multicast where the managed network allows, and everything else on unicast.
The efficiency gap
Why multicast still wins the big live moment
Picture a national final on one channel, 50 000 subscribers watching at once. Over multicast that's a single stream on your network — the load is the same as one viewer. Over unicast it's 50 000 separate streams, and your CDN and egress scale with every one. This is the core reason so many multicast networks are kept in service: for high-concurrency live, the bigger the audience, the bigger the saving — in bandwidth, in cost, and in the near-zero latency a managed network delivers.
When to use which
Put each job on the transport that does it best
- Live linear at scale on your managed network → multicast. Sports and big channels get sub-second latency, guaranteed quality and flat bandwidth.
- VOD, catch-up, time-shift, nPVR and personalized channels → unicast. They're per-viewer by nature, so OTT is the natural fit.
- Mobile, travel, secondary screens and off-net subscribers → OTT. It reaches any network and any device with no multicast infrastructure.
- Markets that demand guaranteed quality → multicast still leads, and that's a valid, well-respected choice — not a legacy one.
Where we fit
One box, both transports
You don't have to choose at the device. inext set-top boxes and our IPTV app handle multicast (UDP/RTP with IGMP) on your managed network and OTT (HLS/DASH, M3U, and Stalker/Ministra/Xtream portals) over unicast — on the same box, in the same home. A subscriber can watch a live channel over multicast and, a moment later, open a VOD title that streams over unicast — one seamless service, each stream on the transport that suits it. And because multicast needs a wired link, every inext box ships with an Ethernet port. Pure unicast, a classic multicast network, or a hybrid of the two — the same box fits all three. We build for both because our clients use both, and we won't tell you the one you've chosen is wrong.
Already on one? Add the other.
Running pure multicast and need OTT reach for mobile and off-net? Or pure OTT and want multicast efficiency for big live events? The box and app support both, so you can extend without re-platforming. We'll help you scope it.
FAQ
Common questions
Talk to us
Deliver live TV the way your network is built for
Tell us about your network, your channels and your audience. We'll help you place multicast and OTT where each performs best — and ship boxes that run both out of the box.