McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Chapter 9 High-Speed Digital Access: DSL, Cable Modem, and SONET

McGraw-Hill©The McGraw-Hill Companies, Inc., DSL Technology ADSL Other DSL Technologies

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 ADSL is an asymmetric communication technology designed for residential users; it is not suitable for businesses. Note:

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 The existing local loops can handle bandwidths up to 1.1 MHz. Note:

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 ADSL is an adaptive technology. The system uses a data rate based on the condition of the local loop line. Note:

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 9.1 DMT

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 9.2 Bandwidth division

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 9.3 ADSL modem

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 9.4 DSLAM

McGraw-Hill©The McGraw-Hill Companies, Inc., Cable Modem Traditional Cable Networks HFC Network Sharing CM and CMTS DOCSIS

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 9.5 Traditional cable TV network

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Communication in the traditional cable TV network is unidirectional. Note:

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 9.6 HFC network

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Communication in an HFC cable TV network can be bidirectional. Note:

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 9.7 Coaxial cable bands

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Downstream data are modulated using the 64-QAM modulation technique. Note:

McGraw-Hill©The McGraw-Hill Companies, Inc., The theoretical downstream data rate is 30 Mbps. Note:

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Upstream data are modulated using the QPSK modulation technique. Note:

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 The theoretical upstream data rate is 12 Mbps. Note:

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 9.8 Cable modem

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 9.9 CMTS

McGraw-Hill©The McGraw-Hill Companies, Inc., SONET SONET Devices SONET Frame Frame Transmission Synchronous Transport Signals STS-1 Virtual Tributaries Higher-Rate Service

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 SONET is a synchronous TDM system controlled by a master clock. Note:

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 9.10 A SONET

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 9.11 Frame format

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Table 9.1 SONET rates STSOCRate (Mbps)SPE (Mbps)User (Mbps) STS-1OC STS-3OC STS-9OC STS-12OC STS-18OC STS-24OC STS-36OC STS-48OC STS-192OC

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 9.12 Data rate

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 9.13 VT types

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Figure 9.14 STS multiplexing