How TAPI supports IP multicast video conferencing

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2, Windows Server 2008, Windows Server 2008 R2, Windows Server 8 Beta

How TAPI supports IP multicast video conferencing

The DHCP service provides Multicast Address Dynamic Client Allocation Protocol (MADCAP) support required for IP multicast video conferencing. DHCP provides unicast addresses for point to point communications between two networked computers. These addresses are unique and specific to a single network. In contrast, MADCAP provides multicast IP addresses, which are shared by many computers. These enable data to be forwarded to all members of a multicast group. The membership of a multicast group is dynamic, which means individual hosts can join or leave the group at any time.

MADCAP is part of the DHCP service, which is an optional component of the Windows Server 2003 family. Clients that are manually configured or use DHCP to obtain a unicast IP address lease can also use MADCAP to obtain multicast IP address configuration. Although MADCAP is packaged in the DHCP service, the DHCP and MADCAP services are independent of each other. You can use a MADCAP server to provide multicast addresses and run DHCP on other servers to provide DHCP services on your network.

MADCAP is built on a client/server model, where multicast conference hosts request addresses from a MADCAP server.

TAPI application directory partitions provide Active Directory directory services for IP multicast conferencing and H.323 telephony. They also publish IP multicast conferences and user IP mappings for H.323 IP telephony and enable users to join conferences and make IP telephone calls. For more information about TAPI application directory partitions, see Tapicfg and TAPI and Active Directory.

For information about installing IP multicast and video conferencing on your network, see Enabling IP multicast.