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.)