Universal Plug and Play, an Intel-centric norm that is used for things like dynamical location and configuration of network devices (it is quite different from Rendezvous in the sense that it covers both service browsing and service interaction).
It is used for remote control of Windows Internet Sharing, punching holes in UPNP-enabled firewalls (MSN and most Bittorrent clients use it for precisely that purpose), etc., but most recently for configuration and media sharing among entertainment devices under DLNA.
Of course, Apple seem to keep wanting to do their own thing, and their own thing only, so there is no native UPnP support in Mac OS X
Resources:
Libraries:
- Coherence, a Python framework.
- gUPnP, a C and GTK single-threaded framework to implement UPnP browsing and manipulation (including the creation of graphical tools)
- libupnp, a similar SDK
Servers:
- FUPPES – seems to play along well with MacPorts.
- uShare UPnP A/V Media Server – simple, straightforward, written in C.
- MediaTomb – trendy, somewhat ugly UI.
- TwonkyVision Media Server (commercial, Mac OS X installer requires you to reboot, which is preposterous)
Clients:
- GMediaRender
- djmount (a installable filesystem, might work with MacFUSE)
- Programatically Controlling a UPNP Firewall – fear.
- CyberGarage has lots of sample code and packages (even for Mac OS X), including:
- CyberLink for Java
- CyberMediaGate for C++