This feature allows [Isolated Web Apps](https://chromeos.dev/en/web/isolated-web-apps) (IWAs) to subscribe to multicast groups and receive User Datagram Protocol (UDP) packets from there. IWAs can now also specify additional parameters when sending UDP packets to multicast addresses.
1. Synchronous video stream from one device to the whole network of devices. For example, imagine in a shopping mall there would be multiple displays which show videos simultaneously on all devices. 2. Device discovery on a local network. mDNS protocol uses multicast sockets under the hood. In short, when a device joins a network, it sends a message: “Hello, I am headphones-10, my ip is ‘20.20.20.14’ . Who else is here?”, other devices reply and in such a manner all devices can know about each other without a central server.
Docs: https://github.com/WICG/direct-sockets/blob/main/docs/multicast-explainer.md https://docs.google.com/document/d/1Wna0lkTrhYoTxOO1GjOrut2nWHO19HEyo9YCk39tXqY/edit?usp=sharing
Explainers: https://github.com/explainers-by-googlers/Multicast-in-Direct-Sockets