Chapter 5. Handshake for the ITU-T Suite of DSL Systems

   


5.1 Handshake Modulation Method

5.1.1 The 4.3125 kHz Signaling Family

5.1.2 The 4 kHz Signaling Family

5.2 Messages and Commands

5.3 Frame Structure

5.4 Information Field Structure

5.5 Parameter Data Structure

5.6 Transmission Order of the Parameters

5.7 Identification (I) Field

5.8 Standard Information (S) Field

5.9 Non-standard Information ( NS ) Field

5.10 Message Composition

5.11 Transaction Types

5.11.1 Basic Transactions

5.11.2 Extended Transactions

5.11.3 Message Segmentation

5.11.4 Example Transactions

5.12 G.hs Start-up/ Clear-down Procedures

5.12.1 Duplex Start-up Procedures

5.12.2 Half-duplex Start-up

5.12.3 Clear-down Procedure

The ITU-T has defined a suite of digital subscriber line (DSL) Recommendations that include symmetric and asymmetric DSL transceivers. Each of the DSL Recommendations contains numerous options and capabilities, and before proper operation can begin, the transceivers need to negotiate and agree on a common set of parameters. ITU-T Recommendation G.994.1 defines handshake (HS) procedures for DSL transceivers to exchange transceiver capabilities and to negotiate and select a common mode of operation.

Handshake Recommendation G.994.1 (also referred to as G.hs) defines the modulation method, protocol, and messages for exchanging capabilities information and negotiating session configuration. The initial issues of G.hs apply to ADSL and SHDSL systems. We expect that later revisions of G.hs will apply to VDSL when the transmission approach is defined in the ITU-T.

This chapter provides an overview of the handshake mechanism defined in G.994.1 [1]. The goal is to provide assistance toward the understanding of the handshake mechanism for DSL systems. We describe the handshake signals and modulation method, initialization and clear-down, the set of commands, message structure, message coding format, and example transaction sequences.


   
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DSL Advances
DSL Advances
ISBN: 0130938106
EAN: 2147483647
Year: 2002
Pages: 154

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