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Cable Modem Remote Access

Another option for remote access is a cable modem. A cable modem operates over the coax cable that is used by cable TV (CATV) providers. Coax cable supports higher speeds than telephone lines, so cable-modem solutions are much faster than analogmodem solutions, and usually faster than ISDN solutions (depending on how many users share the cable). Another benefit of cable modems is that no dialup is required. This is an advantage over analog modems that take a long time to dial and connect to a remote site.

NOTE

The term cable modem is somewhat misleading. A cable modem works more like a LAN interface than an analog modem.

Cable-network service providers offer hybrid fiber/coax (HFC) systems that connect CATV networks to the service-provider's high-speed fiber-optic network. The HFC systems allow users to connect their PCs or small LANs to the coax cable that enters their home or small office, and use this connection for high-speed access to the Internet or to an organization's private network using VPN software.

The cable-network service provider operates a Cable Modem Termination System (CMTS) that provides high-speed connectivity for numerous cable modems. Many cable providers use the Cisco Universal Broadband Router (uBR) for this purpose. The uBR is designed to be installed at a cable operator's headend facility or distribution hub, and to function as the CMTS for subscriber end devices. The uBR forwards data upstream to connect with the Internet and/or the public switched telephone network (PSTN) if telephony applications are deployed. (Note that both Cisco 10000 and 7200 series routers provide uBR CMTS functionality.)

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