Nortel Passport 8672ATME, Using Manual

Page: 33 / 162

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Using the Passport 8672ATME Module
Chapter 2
Passport 8672ATME Module terminology
This chapter contains the following information:
• “ATM terms and acronyms ,” next
• “SONET terms and acronyms” on page 35
• “SONET transmission rates” on page 36
ATM terms and acronyms
Asynchronous transfer mode (ATM) is a connection-oriented, cell-based
technology that relays traffic across a network. ATM provides a cost-effective way
of transmitting voice, video, and data across a network at high speeds. It offers
topology-independent, resilient networking technology.
An ATM cell is a fixed-length packet of 53 bytes. It consists of a 5-byte header
containing address information and a fixed 48-byte information field. The
fixed-length cell size allows you to predict network delays.
The following terms and acronyms are frequently used with ATM information:
• ATM: Asynchronous transfer mode. ATM is a switched, connection-oriented,
fixed-length, cell-based transmission method specifically designed to run at
high data rates and to carry a complete range of user traffic, including voice,
data, and video. ATM uses dedicated media connections running in parallel,
allowing simultaneous multiple connections through a single switch device at
very high speeds.
• PVC: Permanent virtual circuit. Dedicated connection between devices that is
manually set up.