Hardware Reference
In-Depth Information
A typical two-way cable modem connection is shown in
Figure 16.1
.
Originally,cablemodemsusedproprietarytechnologyandwerenotsoldtousersofCATV
Internet access but were leased by the CATV companies offering Internet access to their
cable modem customers. This is because each cable modem on a particular CATV net-
workhadtomatchtheproprietarytechnologythenetworkused.Inlate1998,someCATV
companies began to use DOCSIS-compliant cable modems. DOCSIS refers to devices
that meet the Data Over Cable Service Interface Specification standards established by
Cable Television Laboratories, Inc. (CableLabs). Modems that meet DOCSIS standards
are now referred to as
CableLabs Certified cable modems
. Visit the CableLabs website at
www.cablelabs.com
for a complete list of cable modems that are CableLabs Certified.
Many vendors of traditional modems and other types of communications products, such
as 3Com, ARRIS, Motorola, Cisco, and D-Link, make CableLabs Certified cable mo-
dem-complianthardware.ThemodelssupportedbyyourCATVInternetproviderareusu-
ally dependent on the DOCSIS standard they support.
Table 16.1
provides a brief over-
view of the differences in these standards.
Table 16.1 DOCSIS Standards Overview
