Asynchronous Transfer Mode (ATM) is a new communications technology, which is fundamentally and radically different from previous technologies. ATM is a high-speed, packet switching technique using short fixed-length packets called cells. Fixed-length cells simplify the design of an ATM switch at the high switching speeds involved. The selection of a short fixed length cell reduces the delay and most significantly the jitter, for delay-sensitive services such as voice and video. Thus, ATM presents a single integrated switching mechanism capable of supporting a wide range of traffic types such as voice, video, image and various classes of data traffic. This paper describes the general architecture and design considerations one should take into account while designing an ATM switch. All functional components and their detailed functionality are considered. The switch fabric's structure is the significant component, which affects the cost, performance, capacity, growth capability, and complexity of the switch design. Different types of routing network within the switch are evaluated.