Asynchronous Transfer Mode (ATM) is a networking technology that transmits data in fixed-size packets called cells. Each cell is 53 bytes long, with 48 bytes for data and 5 bytes for header information. This uniform cell size allows ATM to efficiently handle various types of traffic, including voice, video, and data, making it suitable for high-speed networks. ATM operates on a connection-oriented model, meaning a virtual circuit is established before data transfer begins. This ensures reliable communication and quality of service, which is essential for applications requiring consistent performance, such as video conferencing and online gaming.