Asynchronous Transfer Mode (ATM) is a high-speed/high bandwidth, packet-like switching and multiplexing technology, and is capable of transferring voice, video, and data through private and public networks. ATM is uses digital packet switching technology that relay and route traffic by means of an address contained within the packet. ATM uses fixed length packets, called cells, each cell having a fixed length of 53 bytes, a 5 byte header followed by 48 bytes of data.
Internet Protocol (IP) is a data-oriented protocol used for communicating data across a packet-switched internetwork. IP is a network layer protocol in the Internet protocol suite and is encapsulated in a data link layer protocol (e.g., Ethernet). As a lower layer protocol, IP provides the service of communicable unique global addressing amongst computers.