Multicast DHCP, now referred to as MADCAP (Multicast Address Dynamic Client Allocation Protocol), is now included with the Windows 2000 DHCP service, and is used to support dynamic assignment and configuration of IP multicast addresses on TCP/IP-based networks.
Ordinarily, you use DHCP scopes to provide client configurations by allocating ranges of IP addresses from the Class A, B, or C address classes. By using these scopes and ranges of addresses, your clients are configured to use unicast for point-to-point communication between two networked computers.
With Windows 2000 Server, the DHCP service offers MADCAP support in the form of multicast scopes. You configure a multicast scope as you would a regular DHCP scope, but multicast scopes provide scope ranges of Class D multicast IP addresses. These addresses are reserved for multicast operation using directed transmission from one point to multiple points.