Asynchronous Transfer Mode

Thanks for the clarification — you're asking about Asynchronous Transfer Mode (ATM) in networking.

What is Asynchronous Transfer Mode (ATM)?

ATM is a high-speed networking protocol designed for the transmission of data, voice, and video across networks using a fixed-size cell structure.

Key Features:

Fixed Cell Size: Each ATM cell is exactly 53 bytes (5-byte header + 48-byte payload). This uniformity makes it efficient for switching and multiplexing.

Connection-Oriented: ATM requires a virtual circuit to be established before data transfer, ensuring reliable delivery.

Supports Multiple Types of Traffic: Handles voice, video, and data traffic efficiently.

Quality of Service (QoS): Offers different levels of QoS, making it suitable for time-sensitive applications like VoIP and video conferencing.

ATM Layers:

Physical Layer: Defines how bits are transmitted over the physical medium.

ATM Layer: Handles cell creation, routing, and switching.

ATM Adaptation Layer (AAL): Adapts higher-layer protocols into ATM cells.

Use Cases (historically):

Backbone networks in telecoms

WANs (Wide Area Networks)

Voice and video over IP before more modern technologies (like MPLS or Ethernet) took over

Although it's largely obsolete today, ATM was foundational in the development of modern broadband and QoS-aware networking.