Passport Module User Guide

31
Using the Passport 8672ATM Module
Chapter 2
Passport 8672ATM Module technology overview
This chapter contains the following information:
• “ATM terms and acronyms,” next
• “SONET terms and acronyms” on page 33
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.
• SVC: Switched virtual circuit. On-demand connection between an ATM or
frame relay source and destination that lasts for the duration of the
transmission.