Specifications

Installation and Operation Manual Chapter 1 Introduction
ASMi-54C LRS-102 Ver. 2.0 Overview 1-3
The type of SHDSL interfaces provided by the module: central (STU-C: SHDSL
terminal unit – CO) or remote (STU-R: SHDSL terminal unit – remote), as well as
the transport bandwidth, are selected by software, and the module handles all
the signal processing, framing and signaling processing tasks necessary for
SHDSL.bis interoperability.
ASMi-54C modules can be configured by the user to operate either in accordance
with ITU-T Rec. G.991.2 Annex A or F for compatibility with North American (or
similar) networks, or Annex B or G for compatibility with European (and similar)
networks.
Each of the eight SHDSL.bis module ports is supported by a multirate modem that
operates at independently user-selectable data rates in the range of 192 to
5696 kbps in 64 kbps increments. Each group of four SHDSL.bis ports (1 to 4,
and 5 to 8) is handled by a separate SHDSL section.
The terms SHDSL port and SHDSL line are both used below, in accordance with
the conventions used on ASMi-54C supervision terminal screens. However, note
that the terms are interchangeable only when the SHDSL transport function (the
SHDSL line) is handled by a single port: when more ports are used, for example,
by bonding, PAF, etc., the term line represents the group of ports that provide
the transport function.
ASMi-54C supports two types of Transmission Convergence (TC) layers:
• 64/65 octet encapsulation: supports only packet traffic, that is, only
Ethernet services. Each SHDSL port operates as an independent port (2-wires
mode only), but the total bandwidth available for carrying Ethernet traffic
can be increased by bonding together two or four lines (4-wires and 8-wires
mode, respectively), using the PAF (PME Aggregation Function) defined in
IEEE 802.3-2005. Bonding enables achieving line rates up to 22.8 Mbps, or
operating at a longer range by selecting a lower rate.
• HDLC encapsulation: to increase available bandwidth or extend the maximum
range at a given rate, it is possible to bond together two or four lines
(4-wires and 8-wires mode, respectively), a capability referred to as the
M-pair mode per ITU-T Rec. G.991.2.
Ethernet Service
ASMi-54C Ethernet services are supported by the SHDSL transport subsystem and
an internal Ethernet switching subsystem.
• Ethernet transport over SHDSL is provided in accordance with the Ethernet in
the First Mile (EFM) standards, covered by IEEE 802.3-2005.
Ethernet traffic can be encapsulated using the 64/65-octet TPS-TC
(Transmission Protocol Specific – Transmission Convergence) layer as
standardized in IEEE 802.3-2005, or HDLC.
When ASMi-54C provides only Ethernet services, Ethernet traffic is always
encapsulated using the 64/65-octet TPS-TC. With this encapsulation, line
probing according to ITU-T Rec. G.991.2 can be enabled, to automatically
adapt the SHDSL line rate to the condition of the line (noise, loop
attenuation, etc.). When line probing is disabled, the SHDSL line operates at a
fixed rate selected by the user.
Note