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Chapter 2Overview of current CATV network pThe DOCSIS 1.1 version added substantial protocol support to provide dynamicQoS features for packet voice services, in addition to packet data services. Otherenhancements include, for example, baseline privacy and multicast support.DOCSIS 1.2 is a detailed technical specification of a next-generation physical layertechnology (PHY) for integration into the Data-Over-Cable Service InterfaceSpecification. The protocol specification is based on Terayon's Synchronous CodeDivision Multiple Access (S-CDMA) and Broadcom's advanced Frequency AgileTDMA (FA-TDMA), which were first integrated into the IEEE 802.14 protocolspecification [54]. These modulation techniques will allow cable modems to supportan upstream data rate up to 30 Mbps. This version recently became officiallyaccepted as the DOCSIS 1.2 protocol specification [23], in December 2001.Today, CableLabs runs a DOCSIS vendor certification process for cable modems. InJanuary 2002, more than 100 cable modems were DOCSIS 1.0 certified fromapproximately 80 manufacturers.• IEEE 802.14: The IEEE 802 was responsible for the development of LAN/MANprotocol standards. In May 1994, the IEEE 802.14 sub-committee was established todevelop a MAC and PHY specification to support cable networks. This effortresulted in the development of the IEEE 802.14 protocol specification. In July 1997the committee released the first internal draft for the MAC and PHY layers [51].However, MCNS' effort undermined the IEEE 802.14 group's work and was able todefine a specification much quicker than the IEEE. Despite the launch of the NorthAmerican initiative, the IEEE 802.14 committee continued its work with theobjective of creating an international, rather than national, standard.Unfortunately, in September 1999, the joint effort was ceased, followed by thedisbanding of the IEEE 802.14 Working Group in November 1999. This was theresult of the slow standardisation process within the IEEE, which failed to observethe time to market constraint and lost the support of industry [84]. The latest draftspecification, Draft 3, Revision 3 [52], will remain as a proposed specificationwithin IEEE for one year after which time, if there is no interest by any other groupor body, not necessarily within IEEE, it will be withdrawn.2-12