Future Work

The current implementation excludes some topics, which are subject to further work:

Resource reservation mechanisms.

An ConnectionControl object implementation based on the RSVP API described Section appears promising and feasible. However, RSVP implementations themselves are available only for a very limited set of machine and operating-system architectures, currently including mainly Sun workstations under Solaris and SGI workstations under IRIX. In addition, calls of C-language RAPI functions from Java introduces into the implementation native C code, which restricts the architecture independence and portability.

Transmission-rate adjustment.

Since resource reservation and QoS control mechanisms have not been widely deployed yet, dynamic adjustment of the transmission rates is necessary to avoid packet loss due to network congestion. The algorithms I reviewed in Section on page appear suitable, especially the light-weight approach proposed by Busse, Deffner, and Schulzrinne [BDS96].

Session description, announcement, and invitation protocols.

Distance conferencing and lecturing applications require the integration of session and conference management protocols. The set of such protocols developed recently by the IETF Multiparty Multimedia Session Control working group, whose activities I described in Section , seems suitable for this purpose; the mmstream class collection could be expanded by a SDP_SessionMapper class implementing the Session Description Protocol, and by extensions of the SessionExporter and SessionImporter classes implementing the Session Announcement Protocol and the Session Initiation Protocol.

Media-on-demand mechanisms.

Media-on-demand client applications require the incorporation of means by which the transmission of multimedia data streams from remote media-on-demand servers can be requested. Again, the MMUSIC group offers a protocol that easily fits into the mmstream architecture: the set of threads that a SessionAgent object administrates can be extended by SessionRequester threads, which use the Real-Time Streaming Protocol to request and control the on-demand delivery of multimedia data streams from a remote media server.