Network Adapter • The network adapters, commonly known as Chapter 3 network interface cards (NICs) or simply network cards, are responsible for moving data Network Media from the computer to the transmission media. • Network adapters basically convert computer Kuang-hua Chen data into a signal that can be transmitted over Department of Library and Information Science media. National Taiwan University Language & Information Processing System, LIS, NTU 3-2 Network Adapter(Continued) Network Adapter(Continued) • When a network adapter transmits data, it first receives the data from the computer. It attaches its own header containing a checksum and the network card’s address. The data is then converted to signals that are passed over the network media. • The circuitry on the card that does the conversion of the signal is known as a transceiver. Language & Information Processing System, LIS, NTU 3-3 Language & Information Processing System, LIS, NTU 3-4 Adapter Settings IRQ • Like most adapter cards installed in a computer, such as sound and video cards, they are • An IRQ, or interrupt request, value is an assigned value that a device sends to the computer’s configured by setting some parameters. processor to interrupt its processing when it • Set some combination of the following needs to send information. parameters: • Each device in the computer must have a unique –IRQ one. –I/O address –IRQ7: LPT1 – Shared memory address – IRQ12: PS/2 –DMA Language & Information Processing System, LIS, NTU 3-5 Language & Information Processing System, LIS, NTU 3-6 1 I/O address DMA • After a network card has interrupted the CPU • Direct memory access (DMA) enables your with an IRQ, it needs a way to communicate adapter cards to work directly with the with the main board. Most cards use an computer’s memory. input/output, or I/O, address to do this. • If your network card supports DMA transfers, • I/O addresses are given as hexadecimal you should enable it, as this could bring about a numbers. You will see them written as starting significant performance increase. with “0x” or with a trailing “h”. Language & Information Processing System, LIS, NTU 3-7 Language & Information Processing System, LIS, NTU 3-8 Shared memory address Hardware Configuration • Using this method, the network card and • Jumpers software driver use a shared RAM address in – Jumpers are small metal pairs of pins that stick out the high memory to communicate. of the card. You change their configuration by • Shared memory ranges will normally appear as putting small plastic covers with metal internal connectors over them. D8000, C8000, CFFFF, and so on. • DIP switches – Dual In-line Package (DIP) switches are small banks of switches on the adapter card. Language & Information Processing System, LIS, NTU 3-9 Language & Information Processing System, LIS, NTU 3-10 Jumpers DIP switches DIP: Dual In-line Package Language & Information Processing System, LIS, NTU 3-11 Language & Information Processing System, LIS, NTU 3-12 2 Software configuration Adapter Drivers • Network adapters using the Extended Industry • The two standards of drivers that you are most Standard Architecture (EISA), PCI (Peripheral likely to see on the exam are: Component Interface) and MicroChannel – Network Device Interface Specification (NDIS) Architecture (MCA) bus type are almost always – Open Datalink Interface (ODI). configured via software. • Today’s network cards are almost always software configurable. Language & Information Processing System, LIS, NTU 3-13 Language & Information Processing System, LIS, NTU 3-14 Bus Architecture ISA • Bus refers to the connection [that your adapter • The Industry Standard Architecture, or ISA, bus was cards have] to the rest of your computer. designed by IBM and used in the IBM PC. • Any adapter card you have, such as a modem, • This bus was originally designed to transfer 8 sound card,or a printer port cards connect, to megabits per second (Mbps). • ISA is still a popular system for devices that don’t the rest of your computer over this bus. require higher than 16-bit transmissions. • Use ISA bus: –Printers – sound cards – modems Language & Information Processing System, LIS, NTU 3-15 Language & Information Processing System, LIS, NTU 3-16 MCA EISA • IBM introduced MicroChannel Architecture • While processing power was growing, their • MCA operates at 16Mbps or 32Mbps and uses I/O speed was not. The answer to this problem software to configure the resource settings. was the Extended Industry Standard • MicroChannel cards require what is known as a Architecture (EISA) bus. “Reference Disk” to be configured. • EISA slot on a computer’s main board can also be used by an ISA card. • Another important feature: Bus Mastering – allows a card in a computer to operate without the main CPU being involved. Language & Information Processing System, LIS, NTU 3-17 Language & Information Processing System, LIS, NTU 3-18 3 VESA PCI • Why use VESA? • PCI (Peripheral Component Interface) is a – ISA bus was not fast enough for the graphics it relatively new bus type. needed, and EISA was too expensive. • PCI was originally developed to help speed up • Originally designed for video cards, it was later graphics on newer computers. used for hard drive controllers and network • PCI slots are not backward compatible with any cards. other type. • A limiting factor of VLB (VESA Local Bus) • PCI is that it is not tied to any one type of was that it had a limit of three slots on the computer. mother-board. Language & Information Processing System, LIS, NTU 3-19 Language & Information Processing System, LIS, NTU 3-20 PCMCIA USB • PCMCIA is a new type of bus mainly for • USB provides an expandable, hot-pluggable notebook and laptop computers. Plug and Play serial interface that ensures a • All PCMCIA card types use the same 68-pin standard, low-cost connection for peripheral connector. devices. • Another great feature is • Devices suitable for USB range from simple input devices such as keyboards, mice, and – with the PCMCIA software you can insert and remove cards on-the-fly without rebooting the joysticks, to advanced devices such as printers, computer. scanners, storage devices, modems, and video conferencing cameras. Language & Information Processing System, LIS, NTU 3-21 Language & Information Processing System, LIS, NTU 3-22 USB (Continued) IEEE 1394 • Migration to USB is recommended for all peripheral • The IEEE 1394 high-speed serial bus provides devices that use legacy ports such as the PS/2, serial, enhanced PC connectivity and parallel ports. – consumer electronics audio/video (A/V) appliances, storage peripherals • USB 1.0 and 1.1 support data transfer rate up to 1.5 –other PCs Mbps for low-speed devices and up to 12 Mbps for – portable devices. full-speed devices. • IEEE 1394 provides a Plug and Play-compatible • USB 2.0 will support up to 480 Mbps for high-speed expansion interface for the PC. devices. • The 100-Mbps, 200-Mbps, and 400-Mbps transfer – high-quality video conferencing cameras, rates currently specified in IEEE 1394.a – high-resolution scanners, • The enhancements in IEEE 1394.b are well suited to – high-density storage devices. multi-streaming I/O requirements. Language & Information Processing System, LIS, NTU 3-23 Language & Information Processing System, LIS, NTU 3-24 4 Network Adapter Ports Network Adapter Ports (Continued) •BNC Connector: • RJ-45 Connector – Used in Attached – Uses twisted-pair cabling with four pairs of wires Resource Computer Network (ARCNET) and • DIX Connector in thin Ethernet (10Base- – These connectors are not used often anymore but 2). were widely used when thick Ethernet was popular. • The right is a T connector showing three • AUI Connector BNC connectors – The main use today of AUI connectors today is for external transceivers. Language & Information Processing System, LIS, NTU 3-25 Language & Information Processing System, LIS, NTU 3-26 Bounded Media Bounded Media (Continued) • Bounded media are made up of a central conductor • Some of the characteristics you will look at for (usually copper) surrounded by a jacket material. each cable type : • Bounded media are great for LANs because they offer –Cost – high speed – Installation – good security – Capacity –low cost • Sometimes they cannot be used due to distance – Attenuation (Maximum Distance) limitations. – Immunity to Interference • EMI could be a important factor to choose cables. Language & Information Processing System, LIS, NTU 3-27 Language & Information Processing System, LIS, NTU 3-28 Bounded Media (Continued) Electrical Properties • Three common types of bounded media are in • Resistance (電阻) use out in the world: – Resistance only affects the transmission of direct current (DC), and it is measured in ohms. – Coaxial – The resistance causes the energy to be converted to –Twisted pair heat. – Fiber optic – Cables with small diameters have more resistance than cables with large diameters. • Impedance (阻抗) – The loss of energy from an alternating current (AC) is impedance. Language & Information Processing System, LIS, NTU 3-29 Language & Information Processing System, LIS, NTU 3-30 5 Electrical Properties(Continued) Coaxial Cable •Noise (雜訊) • Coaxial cable gets its name because it contains two – Noise can be easy to avoid if route new cable away from conductors that are parallel to each other, or on the lights and other EMI sources same axis. – Try to use shielded cabling if you can, and ground all equipment • The center conductor in the cable is usually copper. • Attenuation