Connectivity IQ      

Internet Access Guide

Introduction Dial-Up Cable Modem ADSL GPRS
WiMAX Satellite Comparison How to Choose FTTH


Internet Access Guide : Cable Modem

Internet access using cable modem is an always-on connection that's once a computer is connected to a CATV network through a cable modem, the computer is always connected to the Internet every time it is turned on. But as in ADSL, nowadays most ISPs offer an option to use log-in process when trying to access the Internet using a cable modem. This is implemented using PPPoE or PPPoA. It derives all PPP features but runs over Ethernet or ATM interface on the cable TV network.

Internet access over CATV network often requires a prior cable TV subscription to the cable TV operator. Most cable TV operators today offer Internet access. In the early days of Internet access using cable modem there were concerns over data privacy and security because the fact that the cable is shared among neighbors sometimes caused one to be able to sneak his neighbor's computer data and learn what websites she had visited on the Internet. But with DOCSIS this problem is overcome by encrypting the communication between cable modem and CMTS.

In most cases, cable Internet access service is charged with a flat monthly rate. But a cable TV operator or ISP may also charge its customers based on usage (downloaded/uploaded bytes or connection time). The ISP usually provides a cable modem for a flat monthly rental fee. But, if you think it is cheaper to buy a cable modem in your subscription plan, then buy one which is compatible with your cable operator's modem standard.

Cable Modem Internet Access
User Equipment Cable modem, Ethernet card (if the cable modem connects through Ethernet port)
Operator Equipment CMTS
Modem Standard DOCSIS 1.0, 1.1, 2.0
Maximum Downstream Data Rate 38 Mbps (shared)
Maximum Upstream Data Rate 30 Mbps (shared)
Connection always-on; log-in (PPPoE/PPPoA)
Charging Flat monthly rate plus cable modem rental fee (optional) or usage-based (transferred bytes or connection time)
Simultaneous Service Cable TV

Back Next