Avaya M-ACCF, User Manual, Page: 34 / 114

Chapter 1 Overview
18 Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide
Cells are de-multiplexed at the other end of the connection and forwarded to the
correct service destination.
Multi-service processing promotes scalability by significantly reducing the number
of changes needed to add new service traffic types to your network.
ATM is Connection-Oriented
ATM is a connection-oriented transport service that requires a communication
channel to be set up between the ATM source and destination end-systems before
ATM cells can pass between them.
Note:
Before a direct data connection can be set up between two end-systems, a
number of control connections are set up. These control connections are beyond the
scope of this guide. If you require further information about control connections,
refer to the ATM Forum’s “LAN Emulation Over ATM” document.
Figure 1.10 shows the logical structure of a communication channel.
Figure 1.10 Communication Channels
Several communication channels can operate over the same physical link. Each
Virtual Path Connection (VPC) contains several communication channels known as
Virtual Channel Connections (VCCs) .
Note: The ATM access module only manages Virtual Channel Connections (VCC).
A VCC is defined as spanning end-to-end, whereas a Virtual Channel (VC) is the
name given to a section of the VCC, refer to Figure 1.11.