In future multimedia communication networks, the ability to multicast 
information will be useful for many new and existing services.  This 
dissertation considers the design of multicast switches for Asynchronous 
Transfer Mode (ATM) networks and proposes one design based upon a slotted 
ring.  Analysis and simulation studies of this design are presented and 
details of its implementation for an experimental ATM network (Project 
Fairisle) are described, together with the modifications to the existing 
multi-service protocol architecture necessary to provide multicast 
connections.  Finally, a short study of the problem of multicast routing 
is presented, together with some simulations of the long-term effect upon 
the routing efficiency of modifying the number of destinations within a 
multicast group.