Connections to the Internet can be described in four basic categories: dialup, proxy, direct and leased. A dialup connection is attained through a modem or similar device. The connection typically provides between 2400 bps (bits per second) and 28,800 bps throughput, which is usually more than adequate for e-mail and for running processes on the remote host. While this type of connection is usually adequate for line-oriented access, it is not suitable for full-screen programs. For instance, utilities such as Mosaic expect to be able to address the full screen of a machine that is directly connected to the internet. To make full use of many of the current Internet resources, then, a more advanced connection is required—at minimum, a proxy connection. A proxy connection is also typically made through a modem, but it has special provisions that enable full Internet access. SLIP (Serial Line IP) and PPP (Point-to-Point Protocol) are two examples of such provisions . Tools such as FTP, Gopher and Mosaic are thereby available for use just as if the connection were directly on the Internet. Direct connections are obtained when the machine being used has a dedicated circuit to the Internet. This can still be a remote connection, but it has the full functionality of a directly connected machine. A good example is ISDN (Integrated Services Digital Network). Lastly, the leased line is a circuit leased from the local telephone company that provides a permanent address on the Internet. The advantage of a permanent address is that it that enables services such as FTP or Gopher to be set up. The leased line varies in throughput from 9600 bps to 45,000,000 bps (45 Mbps).