tailieunhanh - Chapter-18-Connecting to the Internet

ISDN stands for Integrated Systems Digital Network. It’s the new, better, washeswhiter telephone system that is replacing POTS (Plain Old Telephone Service) in some countries, notably in Europe. FreeBSD supports ISDN with the isdn4bsd driver. We won’t look at ISDN further in this book. • Leased lines form the backbone of the Internet. They’re | 2 April 2003 17 00 47 The Complete FreeBSD page 315 In this chapter The physical connection Establishing yourself on the Internet Choosing an Internet Service Provider Who s that ISP Making the connection 18 Connecting to the Internet To implement the reference network shown in the previous chapter we need to do a lot of things that interface with the outside world. They can take some time so we should look at them first What kind of physical connection should we use We ll consider that in the next section. We may want to register a domain. Many people don t but I strongly recommend it. Find out about that on page 317. We may also want to register a network. In our example we have used the network . In real life we can t choose our own network we take what is given to us. We ll look at this on page 318. We need to find an Internet Service Provider. We ll look at what that entails on page 319. The physical connection Just two or three years ago the way to connect to the outside world was simple a phone line. Since then things have changed quite a bit and you may have quite a choice Analogue telephone line connections are still the most common way of connecting small networks in most countries but their bandwidth is limited to about 7 kB s at v 2003 04 02 03 09 55 315 2 April 2003 17 00 47 The Complete FreeBSD . tools page 316 The physical connection 316 best. You can run PPP or SLIP over this kind of line though nowadays most ISPs support only PPP. ISDN stands for Integrated Systems Digital Network. It s the new better washes-whiter telephone system that is replacing POTS Plain Old Telephone Service in some countries notably in Europe. FreeBSD supports ISDN with the isdn4bsd driver. We won t look at ISDN further in this book. Leased lines form the backbone of the Internet. They re invariably more expensive than dialup lines but they can provide quite high speeds in the USA a T1 line will give you 1 536 kbps and in the rest of