The downside is that access is through proprietary mechanisms that limit access to the full range of Internet services. A Dial-Up Internet Connection Figure 2 illustrates this kind of service. When you're connected to your vendor, via a dial-up connection, your desktop machine essentially becomes connected to a LAN at your vendor's site. We recommend a 28.8kbps modem, but a 14.4kbps modem will provide acceptable performance. An increasing number of vendors also offer ISDN access at 64kbps, which provides sufficient performance for basic Internet video services.
Most vendors offer lower hourly prices for heavy users.
In general, we recommend obtaining a SLIP or PPP account, since this allows access to the full range of Internet services. For any but the lightest user, the effective hourly rate is also lower than the other options. You can connect a shared modem pool to a LAN to allow multiple users to access dial-up SLIP or PPP accounts. There are router products available that can establish a dial-up connection to an Internet vendor only when someone is trying to communicate with the outside world. This approach is the closest to a full connection, but offers some savings on the cost of a 24-hour leased line.