Computer networks cabling LANs & WANs

Computer networks cabling LANs & WANs, mạng máy tính, cáp mạng

7/19/2008 1 Module 5: Cabling LANs and WANs 7/19/2008 2 Outline  5.1 Cabling the LAN  LAN physical layer  Ethernet in the campus  Ethernet media and connector requirements  Connection media  UTP implementation  Repeaters  Hubs  Wireless  Bridges  Switches  Host connectivity  Peer-to-peer  Client/server  5.2 Cabling the WAN  WAN physical layer  WAN serial connections  Routers and serial connections  Routers and ISDN BRI connections  Routers and DSL connections  Routers and cable connections  Setting up console connections 7/19/2008 3  5.1 Cabling the LAN 7/19/2008 4 LAN physical layer  Various symbols are used to represent media types.  Each media has advantages and disadvantages.  Some of the advantage or disadvantage comparisons concern:  Cable length  Cost  Ease of installation  Susceptibility to interference 7/19/2008 5 Ethernet in the campus  Ethernet is the most widely used LAN technology.  IEEE 802.3 specification is released in 1980.  IEEE extended 802.3 to three new committees  802.3u (Fast Ethernet)  802.3z (Gigabit Ethernet over Fiber)  802.3ab (Gigabit Ethernet over UTP)  The new generation applications can easily overwhelm a network bandwidth (10M/100M).  Conceder providing GE from the backbone to the end user ?  GE to the desktop is not a standard installation now.  Ethernet technologies in campus network  User level (10Mbps) / Clients or servers (100Mbps)  link between user and network devices  Fast Ethernet can be used to connect enterprise servers.  Fast Ethernet or Gigabit Ethernet, as affordable, should be implemented between backbone devices. 7/19/2008 6 Ethernet in the campus (cont.) 7/19/2008 7 Ethernet media and connector requirements 7/19/2008 8 Connection media  A transceiver is an adapter that converts one type of connection to another. 7/19/2008 9 UTP implementation  EIA/TIA specifies an RJ-45 connector for UTP cable.  The letters RJ stand for registered jack, and the number 45 refers to a specific wiring sequence.  Four of the wires carry the voltage and are considered “tip” (T1 through T4).  The other four wires are grounded and are called “ring” (R1 through R4).  Tip and ring are terms that originated in the early days of the telephone. Today, these terms refer to the positive and the negative wire in a pair.  The wires in the first pair in a cable or a connector are designated as T1 and R1. The second pair is T2 and R2, and so on.  Use straight-through cables for the following cabling:  Switch to router  Switch to PC or server  Hub to PC or server  Use crossover cables for the following cabling:  Switch to switch  Switch to hub  Hub to hub  Router to router  PC to PC  Router to PC 7/19/2008 10 UTP implementation (cont.)