If you connect several devices (phones, tablets, or plotters) to your Automatic Identification System (AIS) WiFi at the same time, you might notice unreliable or “flaky” connections.
Here’s why, without getting too technical:
Transmission Control Protocol (TCP) connections work like a private phone call between two devices. Your AIS WiFi can only maintain one TCP connection per channel. If you try to connect multiple devices on the same channel, it might work if only one device is active, but problems often happen when several devices are switched on. Some AIS WiFi units have multiple TCP channels – in that case, use one device per channel.
User Datagram Protocol (UDP) connections are very different. Think of UDP like someone standing on deck with a megaphone shouting out information: anyone in range can hear it. This means multiple devices can receive the same AIS data at the same time, without problems.
So, if you want to monitor AIS targets on multiple devices around your boat, UDP is usually the easier and more reliable choice.
Compatibility: PCs, Macs, Android, Linux, and iPhone/iPad all support both TCP and UDP. Some units (like the Digital Yacht iAISTX) allow up to 7 devices on UDP at once.
For a more technical comparison of TCP vs UDP, check out this guide.
Captain’s speak: simplified
⚓ AIS (Automatic Identification System) in sailing is a technology that helps boats and ships share their location, speed, course, and other information with nearby vessels and shore stations. It’s mainly used for safety and navigation.
⚓ UDP (User Datagram Protocol) is a way for devices to send data over a network. It’s one of the main protocols used in networking, alongside TCP.
⚓ TCP (Transmission Control Protocol) is a way for devices to send data over a network reliably. It’s one of the main protocols used in networking, alongside UDP.
This article was originally published on 2 August 2023