-level feature sets, and regulatory issues. Operators face challenges such as how to provide detailed, sophisticated, end-to-end SLAs; how to adjust to the need to do maintenance, which will become more critical; and how to evolve from being broadband video providers to being mission-critical ser- vice providers. Developments in the cable-based IP telephony environment are expected in the next couple years. Chapter 12 Broadband Access Alternatives OSS Back-Office Servers and Apps: DOCSIS/ Ticket Granting DOCSIS 1.1 HFC Network Cable Modem FTP/HTTP SYSLOG Record Keeping Provisioning Call Management Managed Server IP Network Media Gateway Controller Announcement Media Gateway Server Controller Signaling Gateway Player Figure 12.5 Cable-based IP telephony DOCSIS 2.0 and 2.x DOCSIS 2.0 increases downstream speed to 40Mbps and upstream throughput to 30Mbps over channels as wide as 6.4MHz, resulting in an increase in the capacity to deliver high-speed data. DOCSIS 2.0 also supports sym- metric services, which means it can serve business customers more adequately. Along with broadband Internet access, VoIP, and tiered services, DOCSIS 2.0 also supports commercial services and videoconferencing. In addition to cable modems, VoIP phones, and residential gateways, it also supports video phones. For downstream data, the modulation technique specified is either 64-QAM or 256-QAM, and upstream it is either QPSK, 16-QAM, or 64-QAM. CableLabs and its members are working on a 2.x version of DOCSIS that will add features such as roaming, committed data rates, Media Access Control (MAC) layer improvements, and better commercial service capabilities. DOCSIS 2.x also adds support for mobile devices. More than two years after CableLabs officially released the DOCSIS 2.0 specifi- cation, more than 60 cable modems are now DOCSIS 2.0 certified, and the technol- ogy is a must-have on modem supply contracts with major operators. However, only a handful of operators have actually deployed DOCSIS 2.0 in their networks. It is only when the c