Running Linux, Fourth Edition

ADSL

The 64-KBit-per-second rate that ISDN supports is nice, but if you want to access multimedia files via the Internet or simply are using the Internet a lot, you may want even more bandwidth. Without drawing additional cables to your house or office, ADSL (Asynchronous Digital Subscriber Line) is a convenient alternative that gives you eight times the bandwidth of standard dial-up access and is run via your ordinary telephone line. A drawback with ADSL is that it only works within a distance of about 3-4 kilometers (2-3 miles) around the next switching station, which makes this service unavailable in rural areas. Note that there are other technologies with similar-sounding names, such as SDSL. While these are fundamentally different on the wire level, setting them up on your Linux box should be no different from ADSL.

ADSL is not dial-up access; once you have logged into your account, you are always connected. Some providers cut your connection after a while (often after 24 hours), upon which you have to log in again in order to regain access.

As we have already mentioned, there are no such things as ADSL cards or ADSL drivers. As far as hardware is concerned, an ADSL connection is just a normal Ethernet connection, using the same cables.

How you connect your Linux box to your ADSL line depends a lot on your ISP. With some ISPs, you rent the necessary equipment, such as an ADSL modem and an ADSL router, as part of your subscription. With others, you have to purchase the necessary ...