width ($/Mbit/s) management and maintenance on demand provisioning ($) upgrades ($) IP/ATM/SONET 750-3750 IP/SONET 750-3750 IP/Ethernet 150-450 GigE advantage 8:1-13:1 5:1-8:1 Some data: Ethernet 10 Mbit/s 100 m Fast Ethernet 100 Mbit/s 0-10 km (fibre dependent) 1000 Mbit/s 0-70 km (fibre dependent) 10 GbE 10 000 Mbit/s 0-40 km (fibre dependent) In the long term Ethernet is expected to take a dominating role in access networks. The equipment price for Ethernet is favourable in comparison to other alternative IP carriers. See the indicative cost comparison in Table 13.1. 13.15 COMBINED ADSL OVER COPPER AND ETHERNET OVER FIBRE SOLUTION By combining ADSL over copper at the drop part and fibre Ethernet between access node and edge node the ADSL part stays short with a potential for a high speed up to 8 Mbit/s. See Figure 13.35. Understanding Changing Telecommunications - Building a Successful Telecom Business Local exchange Voice Up to say 10 lines Interactive TV Video High speed Internet MP3 etc Ethernet Ethernet Ethernet Ethernet ATM, FR switch Edge node Copper Fiber with broad- Network terminal Access node band access server, Broadband High bit rate service provider Figure 13.35 Combined ADSL - Ethernet solution 13.16 CABLE MODEM A cable modem (or cable TV) solution extends from the modem to the head-end. The head-end is a central distribution point for a CATV system. Video signals are received here from satellites and other sources, frequency is converted to the appropriate channels, combined with locally originated signals, and rebroadcast onto the hybrid fibre-coaxial (HFC) plant. The head-end is where the cable modem termination system (CMTS) is normally located. A CMTS is a system of devices located in the cable head-end that allows CATV operators to offer high-speed Internet Older CATV systems were provisioned using only coaxial cable. Modern systems use fibre transport from the head-end to an optical node located in the subscriber neighbour- hood to reduce system noise. Coaxial cable runs from the node to t