How do I enable encryption in kcp-go?

Encryption is enabled by setting a block cipher (e.g., AES-128) during session creation using the SetBlockCrypt method. The README recommends AES for hardware acceleration and provides benchmarks to guide performance choices.

kcp-go vs TCP: which is better for real-time gaming?

kcp-go is superior for real-time gaming due to its UDP base, lower latency, and FEC to handle packet loss without TCP's congestion control delays. However, it requires more setup compared to TCP's out-of-the-box reliability.

How does kcp-go handle packet loss on weak networks?

It combines ARQ for retransmissions, FEC for forward error correction, and precise RTT estimation to minimize delays. The FEC design allows single-pass recovery, reducing retransmission storms on lossy links.

Is kcp-go good for file synchronization over the internet?

Yes, it's used in projects like Syncthing for file sync, leveraging FEC to maintain throughput on unreliable networks. The encryption options also secure data transmission against tampering.

What are the performance benchmarks on Raspberry Pi?

Benchmarks in the README show kcp-go on Raspberry Pi 4 achieving ~4.17 MB/s for EchoSpeed4K, with throughput scaling on better hardware. It's optimized for various platforms, including ARM.

How to implement keepalive in kcp-go?

Since kcp-go lacks built-in keepalive, use a multiplexing protocol like smux (referenced in the README) or add periodic heartbeat messages at the application layer to manage connection liveness.

Open-Awesome

kcp-go

MITGov5.6.64

A high-performance, crypto-secure Reliable-UDP library for Go with FEC support, designed for latency-sensitive applications.

GitHub

4.5k stars806 forks0 contributors

What is kcp-go?

kcp-go is a Reliable-UDP library for Go that provides a secure, ordered, and error-checked stream delivery over UDP packets. It solves the problem of unreliable UDP transport by adding reliability, congestion control, and forward error correction, making it suitable for latency-sensitive applications like online gaming and live streaming.

Target Audience

Go developers building network applications that require low-latency, reliable data transmission over UDP, such as game servers, real-time communication tools, and network acceleration proxies.

Value Proposition

Developers choose kcp-go for its high performance, built-in encryption, FEC support, and compatibility with standard Go net interfaces, offering a battle-tested solution that outperforms raw UDP without the overhead of TCP.

Overview

A crypto-secure Reliable-UDP library for Golang with FEC support.

Use Cases

Best For

Building low-latency game servers that require reliable UDP communication
Creating network acceleration tunnels for improved throughput on lossy links
Developing real-time streaming applications like live broadcasting
Implementing secure UDP-based proxies with packet-level encryption
Synchronizing files over unreliable networks with forward error correction
Multiplexing multiple data streams over a single UDP connection

Not Ideal For

Applications requiring full TCP semantics like built-in connection termination (SYN/FIN/RST) without extra implementation
Environments where UDP traffic is blocked, throttled, or heavily firewalled
Simple client-server models where TCP's out-of-the-box reliability and compatibility outweigh latency gains
Teams lacking UDP networking experience who may struggle with tuning FEC ratios and encryption parameters

Pros & Cons

Pros

High Performance Core

Cache-friendly and memory-optimized design handles over 5,000 concurrent connections on a single commodity server, with benchmarks showing 128+ MB/s throughput in echo tests.

Forward Error Correction

Integrated Reed-Solomon FEC trades 20-30% bandwidth overhead for reduced tail latency on lossy or long-haul links, as detailed in the design characteristics.

Flexible Encryption Options

Supports multiple algorithms like AES, TEA, and Salsa20 with AEAD, ensuring packet anonymity and security; AES-128 is recommended for hardware acceleration via AES-NI.

Seamless Net Integration

Acts as a drop-in replacement for net.TCPConn, compatible with standard net.Conn and net.Listener interfaces, easing adoption in existing Go network stacks.

Cons

No Built-in Connection Management

Lacks TCP-like control messages for connection termination; the README explicitly states the need for application-level keepalive mechanisms, adding implementation burden.

Configuration Complexity

Requires manual tuning of parameters like FEC ratios, encryption settings, and timing intervals, which can be daunting and error-prone for developers new to reliable UDP.

Potential High CPU Usage

The FAQ notes that handling many connections can lead to high CPU utilization, necessitating optimizations like increasing update intervals or using dedicated gateway servers.

Frequently Asked Questions

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