Transport methodsPRO
Overview
Direkt router supports multiple transport protocols for ingest and distribution. When both ends are Intinor units, Bifrost Reliable Transport is preferred for resilience and adaptive bitrate support.
Protocol Summaries
UDP Unicast
Point-to-point delivery. Low overhead, no inherent retransmission. Requires known receiver IP/port.
UDP Multicast
One-to-many on multicast-enabled network infrastructure. Efficient distribution on a LAN. Requires network multicast support (224.0.0.0 – 239.255.255.255) and proper IGMP handling.
RTP
Adds sequence numbers and timestamps on top of UDP for improved handling of jitter/loss patterns.
RTP + FEC
Forward Error Correction adds parity data enabling recovery from small packet loss bursts without retransmission. Consumes extra bandwidth and adds slight latency.
Stream TCP (Push)
Sender initiated reliable stream; receiver buffers (0.3–10 s configurable). Handles loss via retransmission; higher latency for continuity.
TCP on Request (Pull)
Receiver initiated (on-demand) TCP stream from a listening sender. Useful for controlled access / bandwidth management.
Bifrost Reliable Transport (BRT)
Intinor proprietary bonding + ARQ/FEC hybrid enabling:
- Multi-interface bonding (aggregate capacity + redundancy)
- Adaptive bitrate
- Resilience to burst loss
RTMP / RTMPT
For CDN / web TV ingestion. RTMPT encapsulates over HTTP (port 80) when 1935 blocked. Higher overhead and potential latency; use only when RTMP blocked by firewall.
Comparison Matrix
| Protocol | Latency (typ) | Loss Recovery | Overhead | Multi-dest Eff. | Adaptive Bitrate | Firewalls Ease | Primary Use Case |
|---|---|---|---|---|---|---|---|
| UDP Unicast | Very Low | None | Minimal | Low (replicate per dest) | External only | Medium | Direct point-to-point on reliable LAN/WAN |
| UDP Multicast | Very Low | None | Minimal | High (native one-to-many) | No | Low (needs multicast infra) | Internal IPTV / LAN distribution |
| RTP | Very Low | Basic (sequence awareness) | Low | Low | External only | Medium | Slightly improved robustness over UDP |
| RTP+FEC | Low | FEC (proactive) | Medium+ | Low | External only | Medium | Lossy Internet links w/ low added latency |
| Stream TCP | Medium | ARQ retransmit | Medium | Low | No | High (stateful) | Stable but occasional loss networks where integrity prioritized |
| TCP on Request | Medium | ARQ retransmit | Medium | On-demand | No | High | On-demand distribution to selective receivers |
| Bifrost | Low–Adaptive | Hybrid ARQ/FEC + bonding | Medium | High (receiver auto-detect) | Yes | High (single logical flow) | Internet contribution w/ bonding & resiliency |
| RTMP | Medium | N/A (application) | Medium | CDN handled | No | High | Web streaming to CDN |
| RTMPT | Higher | N/A | High | CDN handled | No | Very High | Traversing strict firewalls (fallback) |
Port Planning
| Transport | Typical Port Usage | Notes |
|---|---|---|
| UDP / RTP / RTP+FEC | Even start port + range of ~10 (e.g. 6010–6019) | Reserve contiguous ports for future protocol switches |
| Bifrost | Same UDP range semantics | Bonding may utilize multiple interfaces concurrently |
| Stream TCP | Single configured TCP port | Receiver buffer impacts latency |
| TCP on Request | Listening port on sender; receiver connects | Ensure firewall inbound mapping |
| RTMP | TCP 1935 | Fallback RTMPT over 80 |
Adaptive Bitrate
Only available for a single stream using TCP or Bifrost—see dedicated page:
Configuration Tips
- Always reserve an even starting UDP port then allocate a block of 10 for RTP/FEC/Bifrost simplicity.
- Prefer Bifrost over ad-hoc VPNs for contribution paths needing bonding.
- Start with moderate FEC; tune for either lower latency (reduce block size) or higher robustness (increase) depending on packet loss pattern.