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`1 of 100 DOCUMENTS
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`Copyright 1999 Network World, Inc.
`Network World
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`March 1, 1999
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`SECTION: TECH; Pg. 35
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`LENGTH: 806 words
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`HEADLINE: Cable modems deliver fast 'Net access
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`BYLINE: PAUL NIKOLICH
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`BODY:
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`Cable operators today are deploying cable modem technology that lets subscribers access the Internet over the same
`wires that deliver television signals at speeds 100 times faster than standard V.90 telephone modem technology - and
`without waiting for a dial-up connection.In 1996, several cable operators commissioned the development of the Data
`Over Cable Service Interface Specification (DOCSIS) with the objective of establishing a single specification for
`equipment. DOCSIS covers all operational elements used in delivering data service to end users, including service
`provisioning, security, data interfaces and radio frequency interfaces (RFI). RFIs are the keys to cable equipment
`interoperability.The architecture of the DOCSIS RFI consists of three major components: the Cable Modem
`Termination System (CMTS), installed in the head end, or main facility, of the cable operator; the hybrid fiber coaxial
`(HFC) cable network wiring infrastructure; and the cable modem, installed at customer premises.
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`In order for cable operators to deploy two-way data services, they must first upgrade their wiring infrastructure
`from one-way to two-way. Cable operators also install fiber optic cables from the head end to a fiber distribution node.
`These nodes distribute the signals to 500 to 2,000 homes, depending on configuration.By using fiber optic cabling in the
`trunk section of a cable network, cable operators can reduce the number of amplifiers needed to complete a circuit
`between the head end and the end user, thus greatly increasing reliability and signal quality.Cable modems are used to
`connect high-speed data pipes terminated in the cable operator's head end to the HFC infrastructure. The data
`connection is an IEEE 802.3-compliant 10M or 100M bit/ sec Ethernet port on a router. The router can be connected to
`the Internet via a high-speed (T-1 or faster) WAN interface.Cable modems translate Ethernet packets into radio
`frequency signals that are mapped into an unused 6-MHz television channel slot and broadcast to all the homes by the
`HFC node. The signal is received by any cable modems on the local LAN segment. It can travel anywhere in the
`downstream cable spectrum, from 91 MHz to 857 MHz.The downstream throughput of the cable modem can be 27M
`bit/sec or 40M bit/sec, depending on the quality of the HFC channel from the head end to the subscriber units.The cable
`modem at the cable operator's facility receives signals from all the downstream cable modems on a different set of
`upstream frequencies in the 5-MHz to 42-MHz band. The throughput of this channel is variable, based on the quality of
`the upstream channel. Throughput varies from 160K bit/sec to 10M bit/sec. The DOCSIS architecture provides for one
`downstream channel to send signals to all cable modems, which may broadcast return signals on several different,
`nonoverlapping frequencies.This allows the total throughput of the return channel to be increased by the number of
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`Petitioner Apple Inc. - Exhibit 1069, p. 1
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`

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`Cable modems deliver fast 'Net access Network World March 1, 1999
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`Page 2
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`independent return channels used. For example, the total maximum return channel bandwidth for four 10M bit/sec
`independent upstream channels would be 40M bit/sec.
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`The cable modem translates the downstream radio frequencies into packets, determines if the packets are destined
`for that particular cable modem and sends the packets along to a computer or a LAN on the client side of the cable
`modem.This network connection is currently specified to be 10/100M bit/sec Ethernet, but alternative interfaces, such
`as Universal Serial Bus and PCI, are being considered for lower-cost applications. The cable modem also receives
`packets from clients on the LAN and translates packets onto the upstream frequency to which they have been assigned.
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`A cable modem and its media access control protocol use contention mode and time-division multiplexing (TDM)
`mode. The cable modem allocates a certain portion of time for contention mode or TDM mode, depending on how the
`cable operator configures the network. Contention mode works well under a light load, providing low delay and high
`throughput when needed. TDM mode works well under a heavy load or in cases in which guaranteed throughput is
`desirable. The drawback of TDM is that the peak throughput is limited to the amount of bandwidth allocated to the
`cable modem.In addition to the original DOCSIS specification, conventionally known as DOCSIS 1.0, upgraded
`versions of the specification are under development. These add features such as quality-of-service capabilities, which
`will enable the deployment of packet telephony across the cable infrastructure.
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`Nikolich is vice president of technology and standards at Broadband Access Systems, a Marlborough, Mass.,
`developer of cable access platforms. He also is vice chairman of the IEEE 802 LAN/MAN Standards committee. He can
`be reached at p.nikolich@ieee.org.
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`LOAD-DATE: March 2, 1999
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`Petitioner Apple Inc. - Exhibit 1069, p. 2
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