UDPcast is a file transfer tool that can send data simultaneously to many destinations on a LAN. This can for instance be used to install entire classrooms of PCs at once. The advantage of UDPcast over using other methods (nfs, ftp, whatever) is that UDPcast uses the User Datagram Protocol's multicast

Multicast

In computer networking, multicast is the delivery of a message or information to a group of destination computers simultaneously in a single transmission from the source creating copies automatically in other network elements, such as routers, only when the topology of the network requires...

 abilities: it won't take longer to install 15 machines than it would to install just 2.

By default this protocol operates on the UDP

User Datagram Protocol

The User Datagram Protocol is one of the core members of the Internet Protocol Suite, the set of network protocols used for the Internet. With UDP, computer applications can send messages, in this case referred to as datagrams, to other hosts on an Internet Protocol network without requiring...

port 9000. This default behaviour can be changed during the boot stage.