I'm curious to know if there are any tools for restoring disk images (or even transferring files) via multicast -- for any platform, especially if the project has source available -- where the multicast rate adjusts itself on the fly.

On the Mac, all multicast solutions I am aware of (such as Deploy Studio, and NetRestore before it) make use of multicast ASR (apple software restore), which has one glaring deficiency -- you have to set the multicast speed before you start sending a disk image over the network, and that speed is locked in. Either your clients can keep up and restore, or they can't*.

It seems to me that it must be possible for the multicast server to adjust the data rate, so you basically say "start sending this image", clients connect, and, if they can't keep up, they tell the server so it slows down. (Likewise, I'd expect the server to try speeding up if no client is having difficulties keeping up, and I'd expect to be able to cap that maximum throughput so that other network activities can go on without being resource starved.)

So, what sort of tools are out there? For Linux? Windows? Is there something for the Mac I've overlooked. [It just kills me that it is true that, by the time you get multicast up and going at a good speed to restore a lab, you could've unicasted the data to all the computers and be done.]

* There is a little leeway involved. I think individual clients can say, "I missed a little bit of data" and get it, and they can opt to listen in the next time the image is sent over the network, but on the whole, if they missed it the first go round, you have to image the machine again, and there is no time savings.