© 2006 Cisco Systems, Inc. All rights reserved.

Implementing Secure Converged Wide Area Networks (ISCW)

Module 2: Teleworker Connectivity

© 2006 Cisco Systems, Inc. All rights reserved.

Module 2: Teleworker Connectivity

Lesson 2.2: Describing Cable Technology

© 2006 Cisco Systems, Inc. All rights reserved.

Objectives Describe the components of a typical cable system.

Identify the benefits of a cable system.

Explain how cable uses a part of RF electromagnetic frequencies to transmit.

© 2006 Cisco Systems, Inc. All rights reserved.

What is a Cable System?

CATV originally meant “community antenna television.” This form of transmission shared TV signals.

Cable systems were originally built to extend the reach of TV signals and improve over-the-air TV reception.

Modern cable systems use fiber and coaxial cable for signal transmission.

© 2006 Cisco Systems, Inc. All rights reserved.

Cable Technology Terms Broadband

CATV

Coaxial cable

Tap

Amplifier

HFC

Downstream

Upstream

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Cable System Components

Subscriber Drops

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Cable System Benefits Cable is cost-effective because “broadcast” architecture

is cascaded to users.

Cable supports different services:Analog video

Digital video

Voice

Data

Inexpensive high-speed Internet access enables the application of advanced SOHO and teleworker deployments.

© 2006 Cisco Systems, Inc. All rights reserved.

Digital Signals over Radio Waves

Cable uses a part of RF electromagnetic frequencies.

Cable can transmit signals simultaneously in either direction.

RF portion used is subdivided for the two paths:Downstream: Headend-to-subscriber has 810 MHz of RF bandwidth.

Upstream: Subscriber-to-headend has 37 MHz of RF bandwidth.

© 2006 Cisco Systems, Inc. All rights reserved.

DOCSIS DOCSIS is a standard for certification of cable

equipment vendor devices (cable modem and cable modem termination system).

DOCSIS specifies the physical and MAC layers.

DOCSIS defines RF interface requirements for a data-over-cable system.

Cable equipment vendors must pass certification conducted by CableLabs.

Euro-DOCSIS is a variation adapted for use in Europe.

© 2006 Cisco Systems, Inc. All rights reserved.

Summary Modern cable systems provide two-way communication

between subscribers and the cable operator. Cable operators now offer customers advanced telecommunications services including high-speed Internet access, digital cable television, and residential telephone service.

Cable systems support telephony and data services and analog and digital video services.

DOCSIS defines the communications and operation support interface requirements for a data-over-cable system and permits the addition of high-speed data transfer to an existing CATV system.

© 2006 Cisco Systems, Inc. All rights reserved.

Q and A

© 2006 Cisco Systems, Inc. All rights reserved.

Resources DOCSIS

http://www.cablemodem.com/specifications

Broadband Cablehttp://www.cisco.com/en/US/customer/tech/tk86/tsd_technology_support_category_home.html

CableLabshttp://www.cablelabs.com/

© 2006 Cisco Systems, Inc. All rights reserved.