8
DSLAM and Home Network
8.1 Introduction
Chapters 5–7 presented the various versions of xDSL modems (HDSL, ADSL,
G.lite, and VDSL) with their variants. Our approach has essentially been
focused on the description of these modems from an end user’s perspective. This
chapter is divided into two parts dedicated to DSLAM and to home networking,
respectively. A DSLAM may be seen as the complementary of an xDSL end
user’s modem, at the CO side. We have already introduced in Chapter 3 the
concept of DSLAM as the set of xDSL modems installed in the carrier premises.
For each xDSL modem installed at the end user, another xDSL modem is
installed by the carrier between the MDF and the POP of a packet-switching
network carrier (see Figure 3.6). We detailed in Chapter 3 unbundling and the
technical and regulation aspects related to the management of the MDF and of
the DSLAM. We describe in the first part of this chapter the role and interfaces
of a DSLAM. The second part is dedicated to home networking. In reference to
the ITU-T terminology, we have underlined that an ATU-R and an ATU-C
both correspond to a network termination of type 1 (NT-1) and to a line termination (LT). When we have presented the reference points of an ADSL access system (see Figure 6.5), we have introduced the concept of network terminations
of type 2 (NT-2). In the ITU-T terminology, an NT-2 is an optional piece of
equipment that a carrier may provide to the customer to complement his or her
modem (NT-1). The main objective of an NT-2 is to facilitate a fair share
between various pieces of equipment under the responsibility of the end user of
a unique physical access to a data network via the NT-1. In general, an NT-2
consists of the provision of a LAN service also called a home network to the end
user.
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Broadband Local Loops for High-Speed Internet Access
8.2 DSLAM
In a multioperator environment, DSLAMs have an important impact on the
design of the global...