Setting Multicast Destination IP Address and Port

A multicast program is directed to its destination by its IP address and port. Clients receive the multicast by instructing their network cards to listen for packets arriving at that address and port. In this version of NetShow Server, how destination addresses are set depends on the type of stream you are multicasting:

For Active Streaming format, the destination IP address and port are set when you create the channel in NetShow Administrator using the Channels view. Clients learn which address and port to listen on by downloading the announcement for a program. The announcement points clients to the channel information containing the address and port.
For RTP live audio, WAV audio, and file transfer streams, the destination IP address and port are set for each of the streams in the program when you add streams using the Programs view in NetShow Administrator. In order for a client to receive these multicasts, the address and port you set for the stream must match the address and port specified by the control on the client's Web page. The control, Nsrtpaud.ocx or Nsfile.ocx, is responsible for setting the client's network card correctly.

You can create multiple programs destined for the same IP address; however, you should avoid simultaneously multicasting programs to the same IP address. For example, sending a file to the same destination as an audio multicast can interfere with the audio stream.

Multicast addresses range from 224.0.0.0 through 239.255.255.255. An address in the 239.*.*.* range is recommended for intranets. Avoid using addresses in the 224.*.*.* range. These are reserved for low-level protocols.

IP port numbers range from 1 through 65535. Set port assignments for RTP audio in the range from 16384 through 32768, and always use even numbers.