An Explanation of TCP/IP and Client/Servers

by Brad Ryder

CLIENTS AND SERVERS. There are millions of computers connected to the Internet. Most of them are PCs (this includes Macs) that people use to access the Internet from work or home. Technically, as I understand it, any PC can be a host, since whenever a computer is connected to the Internet it fulfills the role of host (or node) [Hahn, 1996, pp. 19,20]. A host can also be a "server," which means it has the necessary software to provide certain resources.

The distinction needs to be made between a "host" and a "server." A knowledgeable user can configure a computer so that information on it can be accessed by anyone on the Internet. But a host that's also a server provides not just information but resources such as a mailbox or web pages. This is why when you connect to the Internet you need to specify the name of your mail server and your news server, in addition to your primary domain name [Hahn, 1996, pp. 76,77].

To take advantage of these resources, an Internet user needs software, called a "client." This sounds like it should be a person, but it's a computer program designed specifically to access the server's resources. When I first got my Internet account, I had to use a different client for each function -- dialing required one client, then I had to load a gopher client, an FTP client, a mail client, and a browser client as needed. Many people probably still work this way, but integrated programs such as Netscape do all these things. Of course with a shell account, such as on the Nova computer, integrated software is not widely available, so a specific client must be used for the desired server resource.

A user must also find the correct client for his operating system. Fortunately there are clients for Windows 3.1, Windows 95, MacOS, DOS, and even OS/2 [Hahn, 1996, p. 14] so nobody should be short-changed in this respect. Many of the OS developers make shareware version of their clients available on the Internet [Merenbloom, 1996].

TCP/IP. This stands for transport control protocol/internet protocol. Originally created so thousands of defense computers could "talk" to one another, it's required for any computer to be connected to the Internet. TCP/IP must be pronounced correctly: tee-see-pee-eye-pee [Hahn, 1996, p. 20], unless you want to sound like a newbie (like people who originally pronounced DOS like the Spanish word for "two").

TCP/IP creates a "stack" (a filter within the computer's memory) that converts the computer's language to the protocol understood by the Internet. The information is broken into packets, or blocks of data. While IP performs the task of transporting these packets, TCP manages the flow and makes sure everything goes correctly [Hahn, 1996, p. 21].

TCP/IP is no longer restricted to the Internet. It's making an impression on network administrators who need to support servers based on Unix, NT, and OS/2. TCP/IP is the only networking protocol that can practically access all three platforms [Krill and Lee, 1996]. It also may be the best server software for LANs and WANs. Since most LANs are on the Internet anyway, one computer expert is suggesting eschewing NetWare and other server software in favor of TCP/IP [Merenbloom, 1996]. One advantage is standardization. Any computer, regardless of the platform, can be connected to the LAN using only TCP/IP.

Among the disadvantages is the adminstrator's need to set up IP addresses for each computer, although programs, such as Join, are appearing to overcome this [Dryden, 1996]. Plus there are security considerations. Many users are pushing for better encryption before moving to TCP/IP for their sensitive business functions [Dryden, 1995].

REFERENCES

Dryden, P. [August 1995]. TCP/IP to extend reach into homes, businesses. Computerworld, 29, 33, p. 12.

Dryden, P. [February 1996]. Tool makes it easier to change TCP/IP addresses. Computerworld, 30, 7, p. 53.

Krill, P. and Lee, Y. [February 1996]. TCP/IP takes hold. InfoWorld, 1, 18, pp. 1, 18.

Merenbloom, P. [February 1996]. Intranet Web host of choice: TCP/IP, not Novell's NetWare. InfoWorld, 18, 9, p. 49.

Hahn, H. [1996]. The Internet, Complete Reference, Second Edition. Berkeley, Calif.: Osborne McGraw-Hill.