1 Ch 10 LAN Wiring, Physical Topology, and Interface Hardware

2 Network Interface Hardware  A special-purpose HW component, rather than the CPU, handles all the details of packet transmission and reception  Known as a network adapter card or network interface card (NIC)  The NIC makes a copy of the incoming frame, checks the destination address, and, if necessary, interrupts the CPU

3 Ethernet Wiring  Three schemes Correspond to three generations All use same frame format

4 Original Thick Ethernet Wiring  Used heavy coaxial cable  Formal name 10Base5  Called thick wire Ethernet, or Thicknet

5 Original Thick Ethernet Wiring  HW is divided into two major parts NIC handles the digital aspects of communications, including address recognition and error detection Transceiver handles analog signals (data-signal conversion) Attachment Unit Interface (AUI) cable Terminator

6 Thin Ethernet Wiring  Used thinner, more flexible coaxial cable  Cost less to install and no external transceiver are needed  Formal name 10Base2  Called thin wire Ethernet, or T hinnet

7 Twisted Pair Ethernet Wiring  Uses an Ethernet hub  Formal name 10Base-T  Called twisted pair (TP) Ethernet

8 Ethernet Wiring In An Office

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10 Ethernet Wiring In An Office

11 Topology Paradox  Apparently Original Ethernet used bus topology Modern Ethernet uses star topology  In fact, modern Ethernet is Physical star Logical bus (since it functions like a bus) Called star-shaped bus

12 Higher Speed Ethernets  Fast Ethernet Operates at 100 Mbps (Cat. 5 UTP) Formally 100Base-T Two wiring standards 10/100 Ethernet devices are available  Gigabit Ethernet Operates at 1000 Mbps (Cat. 6 UTP) Slightly more expensive