The development of MBone videoconferencing tools has led to a large number of seminars being broadcast over the Internet.
Most MBone seminars have little remote participation.
One reason might be the absence of good floor control mechanisms. This paper describes a tool we developed, called the Questionboard, that implements floor control to facilitate question asking in large-scale MBone seminars. The qb protocol is described including the mechanisms used for reliable transmission of data and the floor control and crash recovery protocols.