Webopedia on Google+Webopedia on TwitterWebopedia on FacebookTech Bytes Blog
Main » TERM » A »

ATM - Asynchronous Transfer Mode

Short for Asynchronous Transfer Mode, a network technology based on transferring data in cells or packets of a fixed size. The cell used with ATM is relatively small compared to units used with older technologies. The small, constant cell size allows ATM equipment to transmit video, audio, and computer data over the same network, and assure that no single type of data hogs the line.

Some people think that ATM holds the answer to the Internet bandwidth problem, but others are skeptical. ATM creates a fixed channel, or route, between two points whenever data transfer begins. This differs from TCP/IP, in which messages are divided into packets and each packet can take a different route from source to destination. This difference makes it easier to track and bill data usage across an ATM network, but it makes it less adaptable to sudden surges in network traffic.

When purchasing ATM service, you generally have a choice of four different types of service:

  • constant bit rate (CBR): specifies a fixed bit rate so that data is sent in a steady stream. This is analogous to a leased line.
  • variable bit rate (VBR): provides a specified throughput capacity but data is not sent evenly. This is a popular choice for voice and videoconferencing data.
  • available bit rate (ABR): provides a guaranteed minimum capacity but allows data to be burstedat higher capacities when the network is free.
  • unspecified bit rate (UBR): does not guarantee any throughput levels. This is used for applications, such as file transfer, that can tolerate delays.






  • TECH RESOURCES FROM OUR PARTNERS
    DID YOU KNOW?
    The Five Generations of Computers

    Learn about each of the five generations of computers and major technology developments that have led to the current devices that we use today. Read More »

    Small Business Marketing's Greatest Hits

    The following compilation of small business marketing tips highlights some of the expert advice published over at Small Business Computing. Read More »

    13 Best Free Android Apps

    From secure messaging to document editing, our top free must-have apps have been rated, reviewed and named the best free Android apps of 2015. Read More »

    QUICK REFERENCE
    5 Best Cloud Storage Services

    With cost and security in mind, we look at five cloud storage options that will suit the needs of most home and SMB owners. Read More »

    Windows 10 Tips for Desktop PC

    Five basic tips to help you customize Windows 10 on your desktop PC. Read More »

    29 Free Android Apps for Cash-Strapped Students

    From wacky alarm clocks to lecture hall tools and after class entertainment, these Android apps are a good fit for a student's life and budget. Read More »