Chapter 10. Introduction to Broadband

Terms you'll need to understand:

  • Broadband

  • Headend

  • Hybrid fiber coax (HFC)

  • Radio frequency (RF)

  • Downstream

  • Upstream

  • Data Over Cable Service Interface Specification (DOCSIS)

  • Cable modem termination system (CMTS)

  • Cable modem (CM)

  • Digital subscriber line (DSL)

  • Asymmetric DSL (ADSL)

  • Symmetric DSL (SDSL)

  • G.SHDSL

  • ISDN DSL (IDSL)

  • Very high data-rate DSL (VDSL)

  • High data-rate DSL (HDSL)

  • DSL access multiplexer (DSLAM)

  • Point-to-Point Protocol over Asynchronous Transfer Mode (PPPoA)

  • PPP over Ethernet (PPPoE)

Techniques you'll need to master:

  • Describing broadband

  • Describing cable modems

  • Describing a cable modem infrastructure

  • Describing DSL

  • Describing the different DSL types

  • Describing ADSL

  • Describing PPPoE and PPPoA

  • Configuring PPPoE and PPPoA

  • Troubleshooting DSL configurations

With the advent and availability of broadband access to the Internet, companies big and small have a whole new world of options. Broadband in this instance is defined as sustained rates above 128Kbps. In this chapter we examine four broadband technologies. We take a cursory look at direct broadcast satellite (DBS) and fixed wireless providers, then we spend a little more time on cable modems, and last we take an exhaustive look at DSL. Broadband enables a remote user to be productive on a network where traditional dial-up falls short. It is further defined as always on, high-speed access supporting voice and video services.

Satellite services can deliver downstream services in bursts up to 400Kbps and upstream speeds reaching 125Kbps. A typical DBS system requires a 1.2 meter (m) or smaller satellite dish, often referred to as a pizza. Workstations are usually connected via an Ethernet cable or universal serial bus (USB) port; the connection usually remains on, allowing you to skip logins for faster access. Geostationary orbit (GSO) satellites are approximately 22,300 miles away; because of this distance and the asymmetric communications, some applications such as Voice over IP (VoIP) do not perform well because of the high latency.

The wireless options discussed are based on line of sight, known as wireless bridges, not a wireless access point that you would typically have inside a home or business. You can obtain 2Mbps throughput at distances up to 25 miles. There are four wireless segments: local multipoint distribution service (LMDS); multichannel multipoint distribution service (MMDS); industrial, scientific, and medical (ISM); and unlicensed national information infrastructure (U-NII) bands. Based on need, distance, and budget, the newer technologies reach speeds from 128Kbps to 53Mbps.



CCNP BCRAN Remote Access Exam Cram 2 (Exam Cram 640 - XXX)
CCNP BCRAN Remote Access Exam Cram 2 (Exam Cram 640 - XXX)
ISBN: N/A
EAN: N/A
Year: 2003
Pages: 183

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