22
C
HAPTER
1: ATM N
ETWORK
B
ASICS
Physical Layer
The physical layer in ATM defines the mapping of cells, much in the same
way that the traditional OSI Physical Layer handles bits, defining physical
media characteristics, line coding and framing. The ATM physical layer
transmits and receives ATM cell streams over a physical medium. It also
checks the integrity of the bits being transferred over a physical medium,
and makes sure that they are error-free. For further information, see
“Physical Layer” on page 223.
ATM Layer
The ATM layer defines how the network carries the cells between users.
ATM Adaptation
Layer (AAL)
The ATM Adaptation Layer is the standards layer that allows multiple
applications to have data converted to and from the ATM cell. There are
five AAL types. The AAL performs Segmentation and Reassembly (SAR)
on cells. It formats data into the 48-byte ATM cell payload, in effect
adapting applications to the cell-based ATM layer. Once the ATM cells
reach their destination, they are reconstructed into higher-level data and
transmitted to the respective local devices. The AAL runs from end-system
to end-system and is transparent to the ATM network. For further
information, see “ATM Adaptation Layer (AAL)” on page 231.
Operation & Maintenance (OAM)
The Operation and Maintenance (OAM) group of network management
functions that provide network fault indication, performance information
and diagnosis functions. For further information, see “Operation &
Maintenance (OAM)” on page 229.
For more information about the ATM layer and ATM cell structure, see
“ATM Layer” on page 226.
Functional Planes
In addition to the ATM layers described above, there are also functional
planes which describe the integration between user and management
devices. Figure 3 shows the relationship between the ATM layers and the
functional planes.
Summary of Contents for CoreBuilder 7000
Page 12: ......
Page 30: ...30 CHAPTER 1 ATM NETWORK BASICS...
Page 32: ...32 CHAPTER 1 ATM NETWORK BASICS...
Page 34: ...34 CHAPTER 1 ATM NETWORK BASICS Figure 8 LANE Network over WAN...
Page 96: ...96 CHAPTER 4 PRIVATE NETWORK TO NETWORK INTERFACE PNNI VERSION 1 0...
Page 184: ...184 CHAPTER 7 LAN EMULATION VERSIONS 1 0 AND 2 0...
Page 206: ...206 CHAPTER 9 DEVICE MANAGEMENT...
Page 222: ...222 APPENDIX A TECHNICAL SUPPORT...
Page 234: ...234 APPENDIX B PROTOCOLS AND INTERFACES...
Page 238: ...238 APPENDIX C COREBUILDER 7000 FAMILY ATM SWITCH SPECIFICATIONS...
Page 242: ...242 APPENDIX D SAFETY INFORMATION...