MPC8280 datasheet(1107/1386 Pages) FREESCALE

1107 / 1386 page

MPC8280 PowerQUICC II Family Reference Manual, Rev. 1

Freescale Semiconductor

33-1

Chapter 33

ATM AAL2

NOTE

The functionality described in this chapter is not available on the MPC8270.

Refer to www.freescale.com for the latest RAM microcode packages that

support enhancements.

The microcode implementation of the ATM adaptation layer type 2 (AAL2) on the MPC8280 is compliant

with the ITU-T recommendations I.363.2 and I.366.1. This chapter describes the functionality and data

structures of AAL2 CPS, CPS switching, and SSSAR and should be used as a supplement to Chapter 31,

“ATM Controller and AAL0, AAL1, and AAL5.”

33.1

Introduction

AAL2 enables the multiplexing of voice and data channels over a single ATM VC. The channels consist

of packets transported within individual ATM cells (see Figure 33-1). Packet lengths are allowed to vary

in order to accommodate bandwidth fluctuations of the individual channels. Each packet has a channel

identifier (CID) so that each AAL2 user (channel) is uniquely identified by the triplet VP | VC | CID.

Figure 33-1. AAL2 Data Units

ATM header

STF

ATM cell

Padding

STF

CPS PDU

Padding

SSSAR SDU

SSSAR

CPS

ATM

SSSAR PDU

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