3.1.5.2.1 Application Sharing and Whiteboarding

An application-sharing or whiteboarding session is identified by the following media information in SDP.

 m=application 1503 tcp msdata
 a=encryption:required
  
  

The media field extension conveys capability for application sharing or use of a whiteboard. The "tcp" value is valid for the proto subfield.

Port 1503 is the standard port used for T.120 and is implemented by the underlying Microsoft NetMeeting client. See section 3.1.5.4 for additional details about encryption of application sharing and whiteboarding.