Shippy's question from yesterday is interesting enough to get my attention—enough attention to deserve a response in its own post1.
Now, I could probably write an entire book on what WSD is and does, but I'm fairly confident you either know already or you're not all that interested. If you're in neither of those categories, I hear there's a really great WHDC site that describes WSD.
So here's a quick list of which parts of Windows Vista use my stack.
- Network explorer. If you click Start->Network on a Windows Vista box (and you have the Network Discovery firewall exception enabled), then you're sending WS-Discovery packets onto the local subnet through my stack. This used to be accomplished solely through NetBIOS, but Vista relies primarily on WS-Discovery for finding WSD devices and other Vista boxes.
- WSD Print Monitor/Scanner Service. Lots and lots (trust me on this one) of printer and scanner vendors are developing WSD-based network printers and scanners. You'll be able to find these printers using the aforementioned Network Explorer, locate drivers with PnP-X, and use the printer using the WSD components built into the print monitor and scan service.
- Windows Meeting Space/People Near Me. This will locate other PNM users on your subnet and allow you to work in a collaborative environment. This is actually really useful when you can set up ad-hoc networks when traveling.
- Background Intelligent Transfer Service. Sortof like an idle BitTorrent system.
- Network Projection. Vista uses WS-Discovery to detect projectors on your subnet, and then render to them without having to deal with the D-SUB cable. I use this often and it's very very cool.
- Function Discovery. FD is actually just another API that's exposed by the OS—it allows apps to discover devices over a number of different protocols (WSD, UPnP, NetBIOS, etc.) and is used by a number of the above features.
Those are the big ones. And, I've written another half-dozen apps that sit on WSD and expose various classes of functionality. WSD was designed with extensibility as a primary goal, and it makes programming really complex network apps damned simple.
1 Read as: the comment box was too tiny to accommodate my ranty response.
The API makes much more sense to me now.
Network Projection sounds super wicked.
I wonder why they decided to re-write BITS to use these APIs when they still have to support downlevel. Does it do more fancy stuff in Vista or are they just gettin' on the bandwagon?
I haven't talked to them in a while, but I suspect it's the cheap access to subnet discovery. They enhanced their featureset for Vista and I think peer-to-peer is a big part of their value add.