Ethernet Network Construct
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Ethernet Network Construct In recent years, networking computers has taken on greater importance as organizations rely on a network for communication applications like electronic mail and for core business operations functions like database applications. This tutorial helps to explain Ethernet and Fast Ethernet, which are two of the most popular technologies used in networking LANs Networks are collections of independent computers that communicate with one another over a shared network medium. Local area networks (LANs) are those networks usually confined to a geographic area, such as a single building or a college campus. LANs, however, are not necessarily simple in design, as they may link many hundreds of computers and be used by many thousands of users. The development of various standards for networking protocols and media has made possible the proliferation of LANs in organizations worldwide for business and educational applications. WANs Often a network is located in multiple physical locations. Wide area networking is the connecting of multiple LANs that are geographically separate. This is accomplished by connecting the different LANs using services including dedicated leased phone lines, Dial-up phone lines both synchronous and asynchronous, satellite links, and data packet carrier services. Wide area networking can be as simple as providing modems and a remote access server to allow remote employees to dial in; or it can be as complex as linking hundreds of branch offices across the world using special routing protocols and filters to minimize the expense of sending data sent over vast distances. Internet With the meteoric rise of demand for connectivity, the Internet has become the communications highway for millions of users. The Internet was initially restricted to military and academic institutions in its infancy but now it is a full-fledged information channel for any and all forms of information and commerce. Internet web site’s now provide personal, educational, political and economic resources to every corner of the planet. Intranet With the advancements made in browser-based software for the Internet, there is now a phenomenon called an Intranet which corporate or other private organizations have developed. An Intranet is a private network utilizing Internet-type tools, but available only within that organization. For large organizations, an Intranet provides an easy access mode to corporate information for the employees through the same type of tools used to go outside the company. Ethernet Ethernet is the most popular physical layer LAN technology in use today. Other Lan types include Token Ring, Fast Ethernet, Fiber Distributed Data Interface (FDDI), Asynchronous Transfer Mode (ATM) and LocalTalk. Ethernet is popular because it strikes a good balance between speed, cost and ease of installation. These strong points, combined with wide acceptance in the computer marketplace and the ability to support virtually all popular network protocols, make Ethernet an ideal networking technology for most computer users today. The Ethernet standard is defined by the Institute for Electrical and Electronic Engineers (IEEE) as IEEE Standard 802.3. This standard defines rules for configuring an Ethernet as well as specifying how elements in an Ethernet network interact with one another. By adhering to the IEEE standard, network equipment and network protocols will interoperate efficiently. Fast Ethernet For Ethernet networks that need higher transmission speeds, the Fast Ethernet standard (IEEE 802.3u) has been established. This standard raises the Ethernet speed limit from 10 Megabits per second (Mbps) to 100 Mbps with only minimal changes to the existing cable structure. There are three types of Fast Ethernet: 100BASE-TX for use with level 5 UTP cable, 100BASE-FX for use with fiberoptic cable, and 100 BASE-T4 which utilizes and extra two wires for use with level 3 UTP cable. The 100BASE-TX standard has become the most popular due to its close compatibility with the 10BASE-T Ethernet standard. For the network manager, the incorporation of Fast Ethernet into an existing configuration presents a host of decisions. Each site in the network must determine the number of users that really need the higher throughput, decide on which segments of the backbone need to be reconfigured specifically for 100BASE-T and then choose the necessary hardware to connect the 100BASE-T segments with existing 10BASE-T segments. Gigabit Ethernet is a future technology that promises a migration path beyond Fast Ethernet so that the next generation of networks will support even higher data transfer speeds. Protocols Network protocols are standards that allow computers to communicate. A protocol defines how computers should identify one another on a network, the form that the data should take in transit, and how this information should be processed once it reaches its final destination. Protocols also define procedures for handling lost or damaged transmissions or “packets.” IPX (for Novell NetWare), TCP/IP (for UNIX, Windows NT, Windows 995 and other platforms), DECnet (for networking Digital Equipment Corp. computers), AppleTalk (for Macintosh computer

and NetBIOS/NetBEUI (for LAN Manager and Windows NT network protocols in use today. Although each network protocol is different, they all are able to share the same physical cabling. This common method of accessing the physical network allows multiple protocols to peacefully coexist over the network media, and allows the builder of a network to use common hardware for a variety of protocols. This concept is known as “protocol independence,” which means that devices that are compatible at the physical and data link layers allow the user to run many different protocols over the same medium....

Network Interface Cards long cable or bus. Many nodes can tap into the bus and begin communication with all other nodes on that cable segment. A break anywhere in the cable will usually cause the entire segment to be inoperable until the break is repaired. Examples of bus topology include 10BASE2 and 10BASE5. 10BASE-T Ethernet and Fast Ethernet use a star topology. Generally a computer is located at one end of the segment, and the other end is terminated in a central location with a hub. Because UTP is often run in conjunction with telephone cabling, this central location can be a telephone...