I'm using Windows Deployment Services on Server 2008 R2 SP1. I'm trying to use the multicast feature. The clients connect, but as the transfer moves along I see in WDS multicast console that the client's transfer speed is "0 Bps" the whole time. Once they reach 100%, the master client fails and the rest continue to transfer using unicast or fail completely (depending on the alignment of the planets). The server and clients are all connected to the same "dumb" switch which, of course, has no IGMP snooping capability. The dumb switch is uplinked to a "smart" switch that has IGMP snooping enabled to keep the multicast from taking down the whole network (which it did before I turned IGMP snooping on). When running wireshark on a client on the switch I see a lot of multicast UDP packets being transmitted. I also see a lot of packets that say "Fragmented IP Protocol" and "Reassembled in #[packet number]." Not sure what to make of that but thought I would report it anyway. Just for fun, I also tried this with the server connected to the smart switch and the clients connected to the dumb switch (which uplinked into the same smart switch) hoping that the IGMP snooping would somehow fix what was going on but I had the exact same problem. I also tried another dumb switch to make sure there wasn't something funky going on with the original one. Please help. I'm fried. TIA

Hello, You can seek help in Setup Deployment forum http://social.technet.microsoft.com/Forums/en/winserversetup/threads or else wait until any of our MVP move this post to concerning WDS forum. Anyways refer a thread for WDS Multicasting:http://social.technet.microsoft.com/Forums/en-US/winserversetup/thread/3942814e-4cda-4f0c-b688-0a9a22087330/Regards, Ravikumar P

Hello, You can seek help in Setup Deployment forum http://social.technet.microsoft.com/Forums/en/winserversetup/threads or else wait until any of our MVP move this post to concerning WDS forum. Anyways refer a thread for WDS Multicasting:http://social.technet.microsoft.com/Forums/en-US/winserversetup/thread/3942814e-4cda-4f0c-b688-0a9a22087330/Regards, Ravikumar P

Hi Ravikumar, In my initial research I came upon the thread you posted but didn't find any useful information. The suggestion in there is to unplug the slowest client because that will speed up the others. I don't have a client that is the "slowest," they are all operating at exactly 0 Bps the entire time.

we've been having similar issues in the school I work in. WDS on server 2008, all switches in the pathway have snooping turned on. When deploying to classrooms, some will deploy 20-30 machines in a multicast session, but only once we start bypass unicasting machines on WDS server, otherwise the whole room will sit there at 0kbps and 0% on wds. Doesn't matter what we try, the transfer won't start until X number of machines are bypassed. for e.g. yesterday we set up a room full of 30 brand new dell machines all set up to join multicast session, WDS displayed 0% / 0kbps, bypassed systematically what WDS thought was the slow client, and when we only had 8 machines in the multicast it leapt into life. We tried to reimage and exactly the same thing happened. Yet other rooms will work with larger numbers of machines. would be interested if you find a solution to this.