Congestion and how to adapt to it should be a primary factor in reliable multicast transport design and continued development. However, this issue is extremely complex and can be in direct opposition to some application desires, such as reliable delivery within a bounded amount of time versus the impact on other network traffic. Managing these tradeoffs and allowing applications to tailor the congestion issue to suite its desires is highly attractive. The means by which a transport adapts to congestion can be quite varied. This area of research covers more than just congestion, however.
Group communication is vastly different in semantics than stream-based semantics.
An example is the presentation of group membership and virtually synchronous activities. Adding to this problem is the varying levels of reliability and application characteristics that each transport provides. There is a clear need for a single API to span as much of the different transports and semantics as possible while still being as simple and usable as possible. Continued Development and Support of RMP and GSRM Continuing development and support of RMP and GSRM is a motivational factor behind much of the research in congestion and APIs. Because of this, improvements to RMP and GSRM will occur as research is performed and results can be incorporated.