Your Internet Roadmap

As a Windows NT user, there are several routes from which you can choose to get to the Internet. These options allow you to choose the Internet connection that makes the most sense based on your budget, geographical location, network (or lack thereof), and access requirements (i.e., what you want to do when you get there). Each route relies on different protocols and network services and has different good points and bad. In brief, you have three choices:

1. Dial in to an Internet host as a terminal and log into a "shell" account. Once you log in, you rely on that host's facilities to access the Internet. (Shell is a UNIX term for the interactive user environment.) Different kinds of shells are available (e.g., the Korn shell, the Bourne shell, the C shell, etc.), but they all support the same basic set of Internet services.

2. Attach to the Internet via a wide-area connection and function as an Internet node. Your system can initiate client connections to Internet servers and also act as a server for other Internet clients (if you are running Windows NT Server). This style of access can operate over a variety of physical links, including dial-in connections, permanent (leased) phone lines, and Integrated Service Digital Network (ISDN) links.

3. Connect to the Internet through a LAN-based gateway. Your system can function as a client, a server, or both. The gateway handles the physical wide-area connections to the Internet. Your system communicates with the gateway over a standard LAN attachment (e.g., Ethernet, Token Ring, Fiber Distributed Data Interface (FDDI), and so on).

All three options provide you with functional connections to the Internet, but each one approaches the connection from a different perspective. Let's look at each of these routes in greater detail.

Terminal Access
To access the Internet as a terminal, you need terminal-emulation software for your system. This software must provide two basic services:

1. The ability to emulate a Digital VT100, VT220, or virtually any well-known ASCII terminal. Most Internet hosts support a wide variety of terminal types, but VT100 emulation is always a safe bet. Also, make sure your shell account is configured for the same type of terminal as your software (look for a TERM= statement in the profile file in your default directory).

2. Support for one or more PC-oriented file-transfer protocols. These protocols allow you to transfer a file from an Internet host to your system. A wide variety of transfer protocols are supported, but Kermit, Xmodem, and Zmodem are the most popular and widely available choices. You can initiate transfers from your system or from the Internet host.

• To send a Zmodem file from the Internet host to your NT system, you would issue the following command on the host: sz <file name>. Your terminal emulator would automatically detect the transfer and start receiving the file. To send a file from your system to the host, you would issue the following command on the host: rz <file name>; then you would initiate the transfer with your terminal-emulation protocol.
• To send an Xmodem file, you would follow a similar command structure (sx to send and rx to receive).
• Kermit uses a different and more complicated interface. If you use Kermit, ask your Internet Access Provider (IAP) for information.

Virtually any terminal-emulation package can satisfy the basic requirements, including the NT Terminal accessory (see Figure 1).

However, the terminal-emulation approach is not without its disadvantages:

You can't apply the power of your NT system to Internet access. Instead, your top-of-the-line system acts like a run-of-the-mill dumb terminal, and you use the horsepower of the host to access Internet services. Your system probably has more CPU, disk, and memory resources to spare than the host does. For example, instead of being able to initiate Telnet (terminal access) or File Transfer Protocol (FTP) services from Windows NT Workstation, you must invoke them using host-based software.

You can't view graphical information on-line. Since the World Wide Web makes heavy use of graphics, when you access the Web through terminal emulation, you only have on-line access to the text. To view the graphical images you must download them and look at them off-line.

You can't hear audio or experience multimedia on-line. A character-based terminal emulator doesn't have these capabilities. However, as with graphics, you can usually download these files if you want.

File transfer is usually a two-step process. First, you transfer a remote file to the host; then, you download the file from the host to your system. Some programs, Gopher being the most notable, can initiate a direct download from the remote Gopher host to your NT system.

Your email--both read and unread--resides on the Internet host. If you want a copy on your system, you must specifically download it. Most hosts don't have user-friendly menu structures to greet you; instead, you see a command-line prompt after you log on. At a minimum, you must start the front-end program (e.g., Telnet, FTP, Gopher, etc.) that handles the Internet service you want to access. More realistically, you'll have to learn a dozen or so native commands (e.g., UNIX commands) so you can view your directory, edit files, delete files, rename files, and so forth.

Some of the drawbacks to this approach are pretty formidable. But, to be fair, there are also advantages to terminal emulation:

It's inexpensive. All you need is a modem, a phone line, and virtually any communications package.

It's simple to set up. If you can install a communications program and make your modem dial a number, you can do it.

It allows you to access the Internet from almost anywhere. You can dial in from any computer system that has a modem connected and communications software installed.

It's platform-independent. If you can't find an NT system, you can use a Mac, a DOS PC, a UNIX workstation, an OS/2 PC, or even a dumb terminal.

Wide-Area Node Access
The simplest way to connect a single system to the Internet and allow it to function as a full-blown Internet node is to use the Serial-Link Internet Protocol (SLIP) or Point-to-Point Protocol (PPP). Both operate over a variety of wide-area connections, including dial-in phone lines, leased lines, and ISDN connections. When you use a SLIP or PPP connection, your NT system connects to an Internet host, and that host acts as a router for all Internet traffic going to or from your system (see figure 1).

SLIP and PPP come from the UNIX environment, and both are used by UNIX systems to connect to the Internet over serial connections. In the NT environment, SLIP and PPP operations are configured under the Remote Access Service (RAS), which is NT's facility for linking to remote networks over wide-area connections (see "The SLIP/PPP Route").

SLIP and PPP are different protocols that accomplish the same goal. SLIP is the older of the two and is dedicated to Transmission Control Protocol/Internet Protocol (TCP/IP) networking. PPP is a more recent, general-purpose protocol that can be used on other types of networks as well (i.e., TCP/IP, NetWare, DECnet, etc.). PPP is also more flexible than SLIP because it can negotiate options (e.g., which protocols to use, whether or not compression is available) during the initial connection. Despite these differences, however, I'll discuss SLIP and PPP together because they accomplish the same results.

SLIP and PPP operate over standard asynchronous dial-in, leased-line, or ISDN connections. Once the end-to-end link is established between your NT system and the Internet host, your system becomes a full-fledged Internet host itself. It can run standard TCP/IP client services, such as Telnet, FTP, and SMTP (Simple Mail Transfer Protocol).

Furthermore, because your system is an Internet node, you can provide TCP/IP server services on the Internet. You can, for example, run Microsoft's FTP Server application and turn your NT system into an Internet file repository. Or you can run the European Microsoft Windows NT Academic Center's (EMWAC's) Hypertext Telnet Protocol (HTTP) server software or one of the commercial packages available and turn your system into a Web server. You can even offer both services, if you wish. However, providing server services is only practical if you have a leased-line or ISDN connection. You don't want to have to maintain a dial-in connection 24 hours a day!

As powerful as the SLIP/PPP approach is, however, it too has its disadvantages:

It is usually more expensive than a terminal connection.

Setting it up is a more difficult task than setting up a simple terminal connection.

It requires a permanent IP address and a related username/password identification. This information must be configured on both your Windows NT system and the Internet host. It effectively locks you into using that specific NT system with that specific host for your Internet access.

On the flip side, however, a SLIP/ PPP connection also offers some powerful advantages:

It uses the power of your NT system to deliver Internet access. Instead of running Telnet, FTP, or other services using host-based software (as in the case of terminal emulation), you can use NT client software to initiate these services.

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