ESD was created to provide a consistent and simple interface to the audio device, so applications do not need to have different driver support written per architecture.
The ESD daemon connects to the sound device and accepts connections from multiple clients, mixing the incoming audio streams and sending the result to the sound device.
Connections are only allowed to clients that can authenticate successfully, alleviating the concern that unauthorized users can eavesdrop via the sound device.
In addition to accepting client connections from the local machine, ESD can be configured to accept client connections from remote hosts that authenticate successfully.
Applications wanting to contact the ESD daemon do so using the libesd library.