lsg28.htm

linux-unix130.linux.and.unix.ebooks130 linux and unix ebookslinuxLearning Linux - Collection of 12 E

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<H2>Linux System Administrator's Survival Guide lsg28.htm</H2>



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<A HREF="#E68E156" >Network Terminology</A>



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<A HREF="#E69E174" >Servers</A>



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<A HREF="#E69E175" >Clients</A>



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<A HREF="#E69E176" >Nodes</A>



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<A HREF="#E69E177" >Local and Remote Resources</A>



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<A HREF="#E69E178" >Network Operating System</A>



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<A HREF="#E69E179" >Network Protocols</A>



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<A HREF="#E69E180" >Network Interface Card</A>



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<A HREF="#E69E181" >Bridges, Routers, and Brouters</A>



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<A HREF="#E69E182" >Gateways</A></UL>



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<A HREF="#E68E157" >What Is TCP/IP?</A>



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<A HREF="#E69E183" >TCP/IP, the Internet, and Layered Architecture</A></UL>



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<A HREF="#E68E158" >IP Addresses</A>



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<A HREF="#E68E159" >The Domain Name System</A>



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<A HREF="#E68E160" >Network Basics</A>



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<A HREF="#E69E184" >Network Topologies</A>



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<A HREF="#E69E185" >Network Media</A>



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<A HREF="#E69E186" > Networking Hardware</A></UL>



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<A HREF="#E68E161" >Summary</A></UL></UL></UL>



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<H1 ALIGN=CENTER>



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<FONT SIZE=6 COLOR="#FF0000"><B>Chapter 28</B></FONT></CENTER></H1>



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<FONT SIZE=6 COLOR="#FF0000"><B>TCP/IP and Networks</B></FONT></CENTER></H2>



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<P>Whenever you deal with networking for Linux or any UNIX product, you inevitably deal with TCP/IP. The term TCP/IP has become a catch-all phrase for many things, most of which don't really apply to the network protocol. Understanding what TCP/IP is isn't strictly necessary to install TCP/IP networking on your Linux machine, but it does help. This chapter begins with a look at network terminology. Then it defines what TCP/IP is and does and what IP addressees and Domain Names are. It ends with a look at the basics of networking.



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<FONT SIZE=5 COLOR="#FF0000"><B>Network Terminology</B></FONT></CENTER></H3>



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<P>Unfortunately, it's difficult to talk about networking unless the terms used are well understood, because a lot of terms in common usage can mean different things depending on the context. To avoid confusion, it's better to begin with the basic definitions. Each term has a formal, rigorous definition, usually in some standard document. Standards are not written in easily understood language usually, so we've tried to simplify the terms a little and use generalizations where possible.



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<FONT SIZE=4 COLOR="#FF0000"><B>Servers</B></FONT></CENTER></H4>



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<P>A server is any machine that can provide files, resources, or services for you. Any machine that you request a file from is a server. In fact, that's the essence of client/server systems, where one machine (the client) requests something from another (the server). One machine may be both client and server many times.



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<P>The more common definition for server is directly related to local area networks, where the server is a powerful machine that holds all the files and large applications. The other machines on the network connect to the server to access their files. In this type of network, a single machine usually acts as the server (and all the others are clients).



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<P>Large server-based networks may have special servers for specific purposes. For example, one server may handle files for the network (the file server), another may handle all print requests (the print server), yet another may handle connections to the outside world through modems (the communications server), and so on. One or more of these functions may be on any individual machine on the network, or you may have several machines on a large network acting as a specific kind of server. You may have two file servers, for example.



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<P>For our purposes in this section, we will need to use both the central and client/server definitions of server, depending on the type of LAN and network services we are dealing with. Simply put, the server is the machine that your machine requests something from.



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<FONT SIZE=4 COLOR="#FF0000"><B>Clients</B></FONT></CENTER></H4>



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<P>As you may have figured out from the definition of server, a client is any machine that requests something from a server. In the more common definition of a client, the server supplies files and sometimes processing power to the smaller machines connected to it. Each machine is a client. Thus, a typical ten PC local area network may have one large server with all the major files and databases on it, and all the other machines connect as clients.



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<P>In the client/server sense of the word, a client is the machine that initiates a request to the server. This type of terminology is common with TCP/IP networks, where no single machine is necessarily the central repository.



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<FONT SIZE=4 COLOR="#FF0000"><B>Nodes</B></FONT></CENTER></H4>



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<P>Small networks that comprise a server and a number of PC or Macintosh machines connected to the server are common. Each PC or Macintosh on the network is called a node. A node essentially means any device that is attached to the network (regardless of the size of the network). Since each machine has a unique name or number (so the rest of the network can identify it), you will hear the term node name or node number quite often. It is more proper to describe each machine as a client, although the term node is in common use. On larger networks involving thousands of workstations and printers, each device is still called a node. If the device has an address on the network, it is a node.



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<FONT SIZE=4 COLOR="#FF0000"><B>Local and Remote Resources</B></FONT></CENTER></H4>



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<P>A local resource is any device that is attached to your machine, such as a printer, modem, scanner, or hard disk. Since the machine doesn't have to go out to the network to get to the device, it is called a local device or local resource.



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<P>Following the same logic, any device that must be reached through the network is a remote resource. Any devices attached to a server, for example, are remote resources. A high-speed color laser printer that may be part of the network is also a remote resource.



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