Multicasting is the ability to deploy a Windows system image to multiple clients without putting extra overhead on the network. With multicast transmission, a single copy of an image is sent over the network and multiple clients receive that copy at the same time, so there is less chance of congestion.
Multicast Transmission on Windows Deployment Server
Step 1. Open the WDS console.
Step 2. Right-click on multicast transmissions and then click create multicast transmission.
Step 3. Provide a name for this transmission.
Step 4. Click Next.
Step 5. Choose the image group and click Next.
Step 6. Choose an auto-cast (starts the transmission automatically when the client requests an image) or scheduled-cast (start the transmission on some criteria like on some specific time) and click Next.
Step 7. Click Finish.