Which technology employs fixed-sized cells for transporting data?

Asynchronous Transfer Mode (ATM) is a technology that is distinguished by its use of fixed-sized cells for data transport. Each ATM cell is 53 bytes long, consisting of a 5-byte header and a 48-byte payload. This uniform cell size allows ATM to provide a predictable and consistent level of performance, which is particularly beneficial for real-time applications like voice and video transmission. The fixed-size cells also facilitate efficient multiplexing of different types of data streams, supporting both constant bit rate and variable bit rate services.

In contrast, Ethernet uses variable packet sizes, which can lead to increased overhead for small data transmissions and latency in certain applications. Packet switching, which is a method used in various data networks, handles data in packets that can vary in size. Circuit switching, primarily used in traditional telephone networks, establishes a dedicated communication path and uses a fixed circuit for the entire duration of the call, but does not operate with fixed-size data cells in the same manner as ATM. This distinction makes ATM particularly suitable for applications requiring stringent quality of service (QoS) guarantees.