Local Area Network Dr. Farid Farahmand Revised on: 10/6/12 Data Network Areas WAN (Wide Area Networks) o  MAN (Metropolitan Area Networks) o  LAN (Local Area Networks) o  Sharing resources in small but geographically dispersed network n LAN Applications backend networks o  personal computer LANs o  interconnecting large systems n  low cost n  (mainframes and large storage devices) n  limited data rate o  high data rate n  share resources o  high speed interface o  printers, hard drives, etc. o  distributed access n  Potential issues for a single LAN o  limited distance o  reliability o  limited number of devices o  capacity o  backbone LANs o  cost n  interconnect low-speed LANs o  High-speed office networks n  Resolve typical drawbacks to LANs used particularly for desktop image n  processing a single page with 200 pictures o  elements (black and white) is about LAN Backbone LAN 3 Mbits! high capacity local storage n LAN Applications storage area networks (SANs) o  separate network to handle storage needs n  à shared storage o  detaches storage tasks from specific servers n  shared storage facility n  eg. hard disks, tape libraries, CD arrays o  accessed using a high-speed network n  eg. Fibre Channel o  improved client-server storage access n  direct storage-to-storage communication for backup n  Project: Build a SAN! Storage Area Networks LAN Topologies Mesh Topology o  Mesh n  Devices are connected with many redundant interconnections between network nodes. n  In a full mesh topology every node has a connection to every other node in the network. Star Topology o  n  All devices are connected to a central switch/hub/repeater. Nodes communicate across the network by passing data through the switch/hub n  Typically has unidirectional links Bus Topology o  n  All devices are connected to a central cable, called the bus or backbone. n  The bus is often terminated on both ends if not connected to any devices. n  The bus is typically duplex. Ring Topology o  n  All devices are connected to one another in the shape of a closed loop, so that each device is connected directly to two other devices, one on either side of it. n  Closed loop with unidirectional links (links are point-to- point) o  Tree Topology Tree n  A hybrid topology. Groups of star-configured networks are connected to a linear bus backbone. http://www.webopedia.com/quick_ref/topologies.asp Frame Transmission Frame is absorbed Frame is removed when it returns to Its source Ethernet – General Most common LAN technology allowing multiple o  devices to connect to each other and share resources Developed by Xerox in 1970 o  Also known as IEEE 802.3 o  IEEE 802.3 Energy Efficient Ethernet Study Group n  Each standards organization focuses on particular layers o  of the protocol stack Institute for Electrical and Electronic Engineers (IEEE) n  World Wide Web Consortium (W3C) n  Internet Engineering Task Force (IETF) n Various Standard Emphasis - Institute for Electrical and Electronic Engineers (IEEE) - World Wide Web Consortium (W3C) - Internet Engineering Task Force (IETF) Other Standardization Bodies Institute of Electrical and Electronics o  Engineers (IEEE) The European Computer Manufacturers o  Association (ECMA) The International Electrotechnical o  Commission (IEC) The International Organization for o  Standardization (ISO).