The Complete Guide to SRT Streaming Gateways

What is an SRT Streaming Gateway?

An SRT streaming gateway is the central routing hub of a professional live streaming infrastructure. It sits between your video sources (cameras, encoders, remote feeds) and your destinations (CDNs, social platforms, recording servers), handling:

• Protocol conversion: receive SRT, output RTMP (and vice versa)
• Stream routing: send one input to multiple outputs
• Failover protection: automatically switch to backup inputs on failure
• Encryption: secure your streams with AES-256
• Monitoring: real-time metrics for every stream

Think of it as a video router that speaks every protocol and never drops a frame.

Why SRT?

SRT (Secure Reliable Transport) was designed by Haivision specifically for live video transport over unpredictable networks. Unlike RTMP (which relies on TCP and falls apart on lossy connections), SRT uses UDP with selective retransmission (ARQ) to maintain stream quality even when the network isn’t perfect. For a detailed comparison of both protocols, see our SRT vs RTMP streaming guide.

Key advantages:

• Packet loss resilience: handles up to 30% packet loss with sufficient latency buffer
• Built-in encryption: AES-128 or AES-256, not bolted on as an afterthought
• Configurable latency: from 20ms on LAN to several seconds for satellite links
• Real-time metrics: RTT, jitter, loss rate, bandwidth, all available via API
• Open source: no licensing fees, growing ecosystem

Core Architecture

A production SRT gateway typically has three stages:

1. Ingest

The gateway accepts incoming streams from various sources:

• SRT listeners waiting for incoming connections
• SRT callers connecting to remote sources
• RTMP receivers for legacy encoder compatibility
• HLS pull for restreaming existing feeds

Each ingest can be independently configured with its own encryption, latency, and connection parameters.

2. Processing

Once ingested, the gateway can process streams:

• Transcoding: change resolution, bitrate, or codec (hardware-accelerated with Intel QSV)
• Audio routing: map audio channels between inputs and outputs
• Failover logic: monitor input health and switch automatically
• Metadata injection: add timecodes, program IDs, or custom data

3. Distribution

The gateway outputs processed streams to multiple destinations simultaneously:

• SRT push to production servers
• RTMP push to YouTube, Twitch, Facebook
• HLS output for web players
• Recording to local or network storage

This three-stage architecture means you can receive in one protocol, process, and distribute in another, all in a single, manageable system.

Setting Up Your First SRT Gateway

Hardware Requirements

SRT is lightweight. A modern gateway can handle dozens of HD streams on modest hardware:

Network Configuration

SRT uses UDP. You’ll need:

1. Public IP or port forwarding for listener mode
2. Firewall rules allowing UDP on your chosen ports (convention: 9000+)
3. Sufficient bandwidth: plan for 1.5x your aggregate bitrate to allow for SRT retransmissions

Software Setup with Vajra Cast

Vajra Cast provides a complete SRT gateway out of the box:

1. Install on your server (macOS or Linux)
2. Open the web interface
3. Create an ingest: choose SRT Listener, set port and latency
4. Create an output: choose your destination protocol and target
5. Connect your encoder and start streaming

The entire setup takes under 5 minutes. For a complete walkthrough including encoder configuration and OBS integration, see our SRT streaming setup guide and OBS SRT streaming guide.

SRT Encryption Deep Dive

Every SRT stream over the internet should be encrypted. SRT supports three key lengths:

• AES-128: fast, sufficient for most use cases
• AES-192: middle ground (rarely used)
• AES-256: maximum security for sensitive content

Configuration is simple: both sides share a passphrase (10-79 characters). SRT derives the encryption key from this passphrase using PBKDF2.

Best practices:

• Use AES-256 for any stream leaving your network
• Use unique passphrases per stream
• Rotate passphrases regularly
• Never transmit passphrases over unencrypted channels

For implementation details including key rotation strategies and compliance considerations, see our SRT encryption and AES-256 deep dive.

Failover and Redundancy

A gateway without failover is a single point of failure. Professional deployments need:

Input Failover

Configure primary and backup inputs with automatic switching:

• Primary: SRT from main encoder
• Backup 1: SRT from redundant encoder
• Backup 2: RTMP from cloud encoder

The gateway monitors all inputs simultaneously and switches in under 50ms when the active input fails.

Output Redundancy

Send the same stream to multiple destinations:

• Primary CDN ingest
• Backup CDN ingest
• Local recording (as ultimate backup)

For mobile production scenarios where reliable connectivity is a challenge, SRTLA bonding combines multiple network connections (cellular, Wi-Fi, Ethernet) into a single resilient SRT stream, providing both higher bandwidth and automatic path redundancy.

Geographic Redundancy

For mission-critical broadcasts, run gateways in multiple locations:

• Primary gateway at venue
• Secondary gateway in cloud
• Both feeding the same CDN with origin failover

Monitoring and Observability

A gateway you can’t monitor is a gateway you can’t trust. Essential metrics:

• Per-stream bitrate: is the source encoding at the expected rate?
• Packet loss: is the network degrading?
• RTT: is latency increasing?
• Retransmission rate: how much bandwidth is spent on recovery?
• Connection state: is every input and output connected?

Vajra Cast exposes all of these in real-time via the web dashboard and a REST API for integration with your monitoring stack.

Next Steps

Ready to build your SRT streaming infrastructure? Start with these guides:

• SRT Encryption Setup: detailed encryption configuration
• SRT Latency Tuning: optimize latency for your network conditions