Unicast endpoint clients (110, 111, 115) on an IP
Unicast network (107, 108) are provided access to
Multicast sessions on an
IP Multicast network (101) through a
Multicast-
Unicast gateway
server (120, 121). The
server obtains information about sessions on the
Multicast network and makes such information available to a Unicast
client on the Unicast network upon request by the
client. Upon being presented with a
list describing the
subject matter of each session, the user at the Unicast
client selects the session to which he or she wants to join, which causes the Multicast-Unicast
server to join the appropriate session on behalf of the requesting client for each
media type in which the joining client wants to be a participant. The server then sets a bi-directional Unicast
User Datagram Protocol (UDP)
stream between itself and the client. All packets then received by the server from the Unicast client are address-translated to the appropriate Multicast session address. In addition, all packets received by the server on the Multicast session address are address-translated and sent to the Unicast client. The Unicast client is then able to participate in the Multicast session as both a sender and a
receiver of packets to and from other Unicast and Multicast clients which are active during the session. Further, the Unicast client is capable of creating a new session, recording a session in the network for later retrieval and playback, and creating and accessing low bandwidth versions of existing sessions.