Cisco Cisco 1800 2800 3800 4-Wire Symmetric High-Bitrate DSL (G.SHDSL) WIC Guía De Información
Q&A
© 2009 Cisco Systems, Inc. All rights reserved. This document is Cisco Public Information.
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G.SHDSL
Overview
Q.
What is G.SHDSL?
A.
Symmetric high-speed DSL (SHDSL) was based on high-data-rate DSL (HDSL) and is specified in the ITU
recommendation G.991.2 (December 2003) titled “Single-Pair High-Speed Digital Subscriber Line Transceivers”.
Single-pair SHDSL transceivers can support selected symmetric user data rates in the range of 192 to 2312
kbps using a Trellis Coded Pulse Amplitude Modulation (TCPAM) line code. Optional extensions described in
Annex F and G allow user data rates up to 5696 kbps.
Q.
What do the different annexes supported by the G.SHDSL high-bit-rate WAN interface cards (HWICs)
specify?
A.
The G.991.2 has the following annexes:
●
Annex A—This annex describes those specifications that are unique to SHDSL systems operating under
conditions such as those typically encountered within the North American network. The clauses in this annex
provide the additions and modifications to the corresponding clauses in the main body.
●
Annex B—This annex describes those specifications that are unique to SHDSL systems operating under
conditions such as those typically encountered within European networks. The clauses in this annex provide
the additions and modifications to the corresponding clauses in the main body.
●
Annex F—The clauses in this annex provide the additions and modifications to the corresponding clauses in
the main body and Annex A for payload data rates up to 5696 kbps. Support for this annex is optional.
●
Annex G—The clauses in this annex provide the additions and modifications to the corresponding clauses in
the main body and Annex B for payload data rates up to 5696 kbps. Support for this annex is optional.
Q.
What are the G.SHDSL HWICs?
A.
The G.SHDSL HWICs are single port modules that enable high-speed Internet and intranet access. They can be
inserted into the HWIC slots on Cisco
®
Integrated Services Routers.
Q.
What are the key features of the G.SHDSL HWICs?
A.
A summary of the features follows:
●
Based on ITU Recommendation G.991.2
●
Symmetrical WAN speeds up to 2.3 Mbps over a single copper pair and up to 4.6 Mbps over two copper pairs
using ITU-T G.991.2 Annexes A and B
●
Symmetrical WAN speeds from 768 kbps up to 5.696 Mbps over a single copper pair and from 1.536 to
11.392 Mbps over two copper pairs using ITU-T G.991.2 Annexes F and G
●
Symmetrical WAN speeds of 2.304 Mbps per pair up to 9.2 Mbps over four pairs on the 4-pair G.SHDSL
WAN interface card (HWIC-4SHDSL) by bonding with Inverse Multiplexing over ATM (IMA) Version 1.1
●
m-pair bonding on the 4-pair G.SHDSL WAN interface card (HWIC-4SHDSL) using Annexes F and G with
symmetrical WAN speeds of 768 kbps to 5.696 Mbps for m = 2 and 768 kbps to 4.096 Mbps for m = 3 and m
= 4
●
Support for dying gasp; uses power status bit (Section 7.1.2.5.3 of G.991.2) for signaling (only on HWIC-
2SHDSL)