cis485_lect1

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cis485_lect1

  1. 1. LECTURE 1: Overview of LAN/WAN Networking CIS 485 Local Area Networks Fall 2003 Instructor: Prof. Song Xing Department of Information Systems California State University, Los Angeles Outlines § Define and identify the different types of networks § Describe the history of LANs and WANs § Discuss LAN and WAN integration, including the basic functions of bridges, routers, gateways, and switches Local Area Networks 2 1
  2. 2. Computer Network § System of computers, print devices, and computer software linked by communications cabling or radio waves § Typically classified according to: § Reach and complexity § Protocols and topologies Local Area Networks 3 Two Types of Networks § Terminal Network § Consists of a single host computer with attached terminals. § Host computers do all or most of the processing, and the terminals imply act as input/output (I/O) devices through which a person gains access to the host’s applications. § Network of Computers § Two or more nodes connected by a data communications medium. § Individual nodes may have terminals attached to them. § A single node on this network can look just like the terminal network. Local Area Networks 4 2
  3. 3. Network Communications Local Area Networks 5 Three Network Subtypes § Local Area Networks (LAN) § Metropolitan Area Networks (MAN) § Wide Area Networks (WAN) Local Area Networks 6 3
  4. 4. Local Area Networks (LAN) § Series of interconnected computers, printing devices, and other computer equipment that share hardware and software resources § Service area usually limited to a given office area, floor, or building § A LAN services a limited geographic area at high speeds—usually 10 million bits per second or higher. § All components of the LAN are commonly owned by the organization that uses it. Local Area Networks 7 Example of a LAN Local Area Networks 8 4
  5. 5. Metropolitan Area Networks (MAN) § A high-speed network covering wider distances than LAN § Spans distances of approximately 100 miles; Links multiple LANs in a large city or metropolitan region § MAN speeds are typically 100 Mbps or higher. § A MAN is typically implemented by the fiber distributed data interface (FDDI). It operates at 100 Mbps over fiber optic cable for distances up to 200 kilometers. Local Area Networks 9 Example of a MAN Local Area Networks 10 5
  6. 6. Wide Area Network (WAN) § Far-reaching system of networks that usually extends over 30 miles and often reaches across states and continents § However, some WANs are confined to a limited geographic area, like a LAN. Local Area Networks 11 LAN/MAN/WAN Comparison LAN MAN WAN Distance Limited —typically up Limited —typically up Unlimited to 2,500 meters or 2 to 200 kilometers or miles 100 miles Speed High—typically in High—typically Slower —usually 1.5 excess of 10 Mbps— 100 Mbps Mbps 10,100 and 1,000 are standard Media Locally owned — Locally owned and Locally owned and twisted -pair wires, fiber common carrier — common carrier — optic cable, wireless twisted -pair wires, fiber twisted -pair wires, (not satellite) optic cable coaxial cable, fiber optic cable, wireless to include satellite Nodes Can be any, but most Can be any, but most Can be any, but most are desktop computers are desktop computers are desktop computers and minicomputers Local Area Networks 12 6
  7. 7. Network Classification § Enterprise network, an organization’s complete network § Combination of LANs, MANs, or WANs that provides users with an array of computer and network resources to complete different tasks § With the advent of LANs, many organizations installed departmental LANs to improve the productivity of work groups. § To take a benefit to having users on one LAN communicate with users or applications on other LANs or on the WAN, the various networks were connected together to form one corporate-wide network, the enterprise network. Local Area Networks 13 Enterprise Network Local Area Networks 14 7
  8. 8. The Internet § An internet (with a lowercase ‘i’) is the interconnection of two or more networks. An enterprise networks just described is an example of an internet. § The Internet (with an uppercase ‘I’) is a specific instance of an internet. § The Internet is a global network of networks. It is made up of hundreds of networks, thousands of nodes, and millions of users throughout most countries of the world. Local Area Networks 15 Identifying a Network Type § Communications medium § Wire cable, fiber-optic cable, radio waves, microwaves § Protocol § How networked data is formatted into discrete units § How each unit is transmitted and interpreted § Topology § Physical layout of cable and logical path § Network type § Private versus public Local Area Networks 16 8
  9. 9. LAN/WAN History: 1960s § First WAN § Hypertext § Use of fiber optics for phone signals § Beginning of ARPANET § Packets and packet switching § UNIX § Telecommunications equipment § First IMP prototype Local Area Networks 17 LAN/WAN History: 1970s § Ethernet § Telecommunications § ARPANET - 15 sites conversion from § E-mail analog to digital § Terminal emulation § X.25 § International § First wireless connections to gateway ARPANET § Internet Protocol § LSI and VLSI chips § ICCB Local Area Networks 18 9
  10. 10. LAN/WAN History: 1980s § BITNET § Internetwork hosts § IBM’s PC § 5,000 in 1986 § 100,000 in 1989 § Dial-up modem technology § “Cyberspace” § TCP and IP adopted § T-carrier services as protocol suite for § NFSNET ARPANET § Desktop authoring § First PC LAN and multimedia § Arrival of Internet § SNMP Local Area Networks 19 LAN/WAN History: 1990s § ARPANET retired § SS7 technology § NSFNET opened to commercial use § First cyberbank § Internet service providers § Over 16 million Internet hosts Local Area Networks 20 10
  11. 11. LAN/WAN History: 2000s § IPv6 used for Internet2 backbone communications § Video and radio capability § Prices of 1-Gbps devices fall as competition increases Local Area Networks 21 LAN/WAN Integration § Becoming more advanced through networking devices § Bridges § Routers § Gateways § Switches § Hubs § Repeaters Local Area Networks 22 11
  12. 12. Internetworking § Many times it is necessary to connect a local area network to another local area network or to a wide area network. § Local area network-to-local area network connections are often performed with a bridge-like device. § Local area network-to-wide area network connections are usually performed with a router. § A switch can be used to interconnect segments of a local area network. Local Area Networks 23 Why Interconnect? § To separate / connect one corporate division with another. § To connect two LANs with different protocols. § To connect a LAN to the Internet. § To break a LAN into segments to relieve traffic congestion. § To provide a security wall between two different types of users. Local Area Networks 24 12
  13. 13. Bridges § Connect different LANs or LAN segments using the same access method Local Area Networks 25 Routers § Connect networks having the same or different access methods and media § Forward packets and frames to networks by using a decision-making process based on: § Routing table data § Discovery of most efficient routes § Preprogrammed information from network administrator Local Area Networks 26 13
  14. 14. Routers Local Area Networks 27 Gateways § Enable communications between two different types of networked systems Local Area Networks 28 14
  15. 15. Switches § Hub: multi-port repeater § Switch: combines the functions of a bridge and a hub § Link network segments § Forward and filter frames between segments § Done in hardware Local Area Networks 29 Networking Devices Local Area Networks 30 15

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