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Chapter 2Overview of current CATV network pHowever, not all DVB/DAVIC vendors have obtained the verification from theDVB/DAVIC Interoperability Consortium (DDIC). Moreover, the number oforganisations producing DOCSIS equipment is considerably large when compared withthe number of DVB/DAVIC vendors (≈ 10).Most cable modems, currently deployed as a commercial service, are external cablemodems (with Ethernet or/and USB ports). Some cable modems have advancedcapabilities. For instance, Motorola and Com21 have manufactured external cablemodem routers that have a 4-port hub, built-in NAT, Dynamic Host ConfigurationProtocol (DHCP) server and firewall for creating home networks. Interactive, Toshiba,Tellabs and Cisco Systems have produced external cable modems with PacketCableTechnology [80] that allows VoIP calls (and may be capable of video over IPtransmissions in the future).Moreover, Terayon is the first organisation that has already produced cable modemscompliant to DOCCSIS 1.2 [23], which includes advanced PHY capabilities and dualmodulation techniques, S-CDMA and FA-TDMA. DOCSIS 1.2 triples the upstreamcapacity of DOCSIS 1.1 (up to 30 Mbps with 64-QAM modulation) enabling operatorsto create new services for residential and business markets, such as video conferencingand peer-to-peer applications.Currently, the number of cable modems shipped worldwide has reached the top-mark of15 million modems, with Motorola, Toshiba and Thomson leading the market with39%, 17% and 12% of the sales, respectively [126].2.7 Competing technologiesMultiple broadband competing technologies are being developed to provide high-speedaccess to small office and residential areas. Digital Subscriber Line (xDSL), and severalforms of passive optical networks (FTTx) are direct competitors to HFC infrastructuresand the challenge is to work out the least expensive and most efficient solution, whiletaking into account the different boundary conditions. In this section, a review of thesecompeting technologies is addressed.2-14