© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Teleworker Connectivity Describing Cable Technology
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Cable Technology Terms
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Cable Technology Terms Broadband CATV Coaxial cable Tap Amplifier HFC Downstream Upstream
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Cable System Standards StandardDescription NTSCTechnical standard for analog TV system used in North America Uses a 6-MHz modulated signal PALColor encoding system used in broadcast television systems in most of the world Uses 6-MHz, 7-MHz, or 8-MHz modulated signal SECAMAn analog color TV system used in France and some Eastern European countries Uses an 8-MHz modulated signal
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Cable System Components
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Cable System Components ComponentDescription Antenna siteA location with the main receiving antennas and satellite dishes HeadendA facility where signals are received, processed, formatted, and combined Transmits cable signals through distribution network to subscribers Transportation network Links a remote antenna site to a headend Distribution networkComprised of trunk and feeder cables Subscriber dropDevices and parts used to connect to the distribution network
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Cable Features
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v What Is Cable? Cable refers to use of coaxial cable or fiber for signal transmission. Cable solves the problem of poor over-the-air TV reception. CATV originally meant community antenna television.
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Cable System Benefits Cable is cost-effective as 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.ISCW v Digital Signals over RF Channels
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v 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.ISCW v 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.ISCW v Data over Cable
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Fiber Benefits Lessens the use of amplifiers Thin and lightweight Covers long distances Cheaper than pure coaxial network Easy to handle Immune to external interference
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v HFC Architecture Cable network is segmented into service areas (segments): Less amplifiers are cascaded Reliability and quality is improved Operating costs are reduced
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Data over Cable Data service runs between cable modem and CMTS. Users on a segment share upstream and downstream bandwidth.
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Cable Technology: Putting It All Together
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Putting Cable Technology All Together
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Data Cable Technology Issues Subscribers in a service area share the cable: Bandwidth shortage (can be resolved by the cable operator) Security issues (can be resolved by the cable modem)
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Provisioning a Cable Modem
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Process for Provisioning a Cable Modem
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Process for Provisioning a Cable Modem
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Process for Provisioning a Cable Modem
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Process for Provisioning a Cable Modem
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Process for Provisioning a Cable Modem
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Process for Provisioning a Cable Modem
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Process for Provisioning a Cable Modem
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Process for Provisioning a Cable Modem
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Summary Main cable system components are headend, transportation network, distribution network, and subscriber drop. The cable system standards include NTSC, PAL, and SECAM. The term cable describes the use of a coaxial cable for signal transmission. Cable system architecture provides a cost-effective broadcast architecture cascaded to users. A cable system supports multiple services: analog and digital video, voice, and data. DOCSIS is the cable service interface standard for data carried across RF interfaces. The DOCSIS CMTS communicates through channels with cable modems located in subscriber homes.
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v Summary (Cont.) An RF spectrum is defined for the downstream and upstream paths. The HFC architecture consists of fiber and coaxial cabling, which carry RF signals toward the subscriber. Fiber is used to overcome the limitations of the trunk coaxial cable. Users share bandwidth in the service area. The cable modem provisioning process is defined by DOCSIS.
© 2006 Cisco Systems, Inc. All rights reserved.ISCW v