Avaya M-ACCF/SF 사용자 설명서

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Chapter 1
Overview
Avaya M770 M-ACCF/SF ATM Access Modules User’s Guide
15
Network Layer Concepts — ATM & ATM Adaptation
This Section describes the following concepts behind the network layer architecture 
of a typical ATM network:
The Layered Network Architecture
Asynchronous Transfer Mode (ATM) is one part of the layered network architecture. 
This architecture is shown in Figure 1.8. 
Each of the layers is discussed in turn; starting with the Upper Layer and working 
down to the Physical Layer.
Figure 1.8
Network Layer Architecture
ULP PDUs
AAL5  PDUs
LAN Emulation
Frames
ATM Cells
SONET or SDH
media
PDUs
Protocol Data Units
Key
frames
Logical flow
Physical flow