ITM 301 Chapter Notes - Chapter 6: Pci Express, Expansion Card, Data-Rate Units

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Chapter 6: Network Hardware, Switching,
and Routing
NICs (Network Interface Cards)
NICs (network interface cards, also called network adapters or network cards) enable a
work- station, server, printer, connectivity device, or other node to receive and transmit
data over the network media.
NICs contain a transceiver, which transmits and receives data signals.
NICs belong to both the Physical layer and Data Link layer of the OSI model because
they issue data signals to a wire or into the air and assemble or disassemble data
They also interpret physical addressing information to ensure data is delivered to its
proper destination.
they perform the routines that determine which node has the right to transmit data over a
network at any given instant
Types of NICs
As you design or troubleshoot a network, you will need to know the characteristics of the
NICs used by its clients, servers, and connectivity devices.
NICs come in a variety of types depending on the following:
oAccess method (for example, Ethernet)
oNetwork transmission speed (for example, 100 Mbps versus 1 Gbps)
oConnector interfaces (for example, RJ-45 versus SC)
oNumber of connector interfaces, or ports
oMethod of interfacing with the computer’s motherboard (for example, on-board,
expansion slot, or peripheral) and interface standard (for example, PCIe or USB)
oManufacturer (popular NIC manufacturers include 3Com, Adaptec, D-Link, IBM,
Intel, Kingston, Linksys, Netgear, SMC, and Western Digital, to name just a few)
oSupport for enhanced features, such as PoE, buffering, or traffic management
Expansion Board NICs
A computer’s bus is the circuit, or signaling pathway, used by the motherboard to
transmit data to the computer’s components, including its memory, processor, hard
disk, and NIC.
oA computer’s bus may also be called its system bus or main bus.
The capacity of a bus is defined principally by the width of its data path (expressed in
bits) and its clock speed (expressed in MHz).
A data path size equals the number of bits that it can transmit in parallel at any given
As the number of bits of data that a bus can handle increases, so too does the speed
of the devices attached to the bus.
The motherboard contains expansion slots, or openings with multiple electrical
contacts, that allow devices such as NICs, modems, or sound cards to connect to the
computer’s expanded bus.
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The devices are found on a circuit board called an expansion card or expansion
Inserting an expansion board into an expansion slot establishes an electrical
connection between the expansion board and the motherboard. Thus, the device
connected to the expansion board becomes connected to the computers main circuit
and part of its bus.
Multiple bus types exist, and to become part of a computer’s bus, an expansion
board must use the same bus type.
The most popular expansion board NIC today is one that uses a PCIe bus.
PCIe (Peripheral Component Interconnect Express) is a 32-bit bus capable of
transferring data at up to 1 Gbps per data path, or lane, in full-duplex transmission.
PCIe slots vary depending on the number of lanes they support: An x1 slot supports a
single lane,an x2 slot supports two lanes, and so on.
Each lane offers a full-duplex throughput of up to 1 Gbps. A PCIe slot can support up
to 32 lanes.
On-Board NICs
Not all devices are connected to a computer’s motherboard via an expansion slot or
peripheral bus. Some are connected directly to the motherboard using on-board
oFor example, the electrical connection that controls a computer’s mouse
operates through an on-board port, as does the connection for its keyboard
and monitor.
Most new computers also use on-board NICs, or NICs that are integrated into the
mother- board.
Such NICs use the same kinds of bus interfaces as expansion board NICs—for
example, PCIe. A significant advantage to using an on-board NIC is that it saves
space, freeing expansion slots for additional peripherals.
NICs are designed for use with either wired or wireless networks.
Wireless NICs, which contain antennas to send and receive signals, can be found for
all of the bus types dis- cussed in this chapter.
Installation and configuration for wireless NICs is the same as for wired NICs.
Installing and Configuring NICs
Most new clients, servers, and connectivity devices will arrive with their NICs preinstalled
and functional.
However, someday you might want to upgrade the NIC in a client workstation to one that
can handle faster transmission speeds or add NICs to your server, for example. In that
case, you need to know how to install NICs properly.
Installing NIC Hardware
It’s always advisable to start by reading the manufacturers documentation that
accompanies the NIC hardware. The following steps generally apply to any kind of
expansion card NIC installation in a desktop computer, but your experience may vary
To install an expansion card NIC:
1. Make sure that your toolkit includes a Phillips-head screwdriver, a ground strap, and
a ground mat to protect the internal components from electrostatic discharge. Also,
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make sure that you have ample space in which to work, whether on the floor, a desk,
or a table.
2. Turn off the computers power switch, and then unplug the computer. In addition to
endangering you, opening a PC while it’s turned on can damage the PC’s internal
circuitry. Also unplug attached peripherals and the network cable, if necessary.
3. Attach the ground strap to your wrist and make sure that it’s connected to the ground
mat underneath the computer.
4. Open the computers case. Desktop computer cases are attached in several different
ways. They might use four or six screws to attach the housing to the back panel, or
they might not use any screws and slide off instead. Remove all necessary screws
and then remove the computer’s case.
5. Select a slot on the computers motherboard where you will insert the NIC. Make
sure that the slot matches the type of expansion card you have. Remove the metal
slot cover for that slot from the back of the PC. Some slot covers are attached with a
single screw; after removing the screw, you can lift out the slot cover. Other slot
covers are merely metal parts with perforated edges that you can punch or twist out
with your hands.
6. Insert the NIC by lining up its slot connector with the slot and pressing it firmly into
the slot. Don’t be afraid to press down hard, but make sure the expansion card is
properly aligned with the slot when you do so. If you have correctly inserted the NIC,
it should not wiggle near its base. A loose NIC causes connectivity problems. Figure
6-4 shows a close-up of a NIC firmly seated in its slot.
7. The metal bracket at the end of the NIC should now be positioned where the metal
slot cover was located before you removed the slot cover. Attach the bracket with a
screw to the back of the computer cover to secure the NIC in place.
8. Make sure that you have not loosened any cables or cards inside the PC or left any
Screws or debris inside the computer.
9. Replace the cover on the computer and reinsert the screws that you removed in Step
if applicable. Also reinsert any cables you removed.
10. Plug in the computer and turn it on. Proceed to configure the NIC’s software, as
discussed later in this chapter.
Physically installing a peripheral NIC is much easier than installing an expansion card NIC.
In general, you simply insert the device into the appropriate slot.
On servers and other high-powered computers, you may need to install multiple NICs.
For the hardware installation, you can simply repeat the installation process for the first
NIC, choosing a different slot.
The trick to using multiple NICs on one machine lies in correctly configuring the software
for each NIC. Simple NIC configuration is covered in the following section. The precise
steps involved in configuring NICs will depend on the computer’s operating system.
Installing and Configuring NIC Solutions
A device driver (sometimes called, simply, a driver) is software that enables an
attached device to communicate with the computer’s operating system.
When you purchase a computer that already contains a peripheral, the device drivers
should already be installed.
However, when you add hardware, the proper device driver must be installed.
Operating systems come with a multitude of built-in device drivers. In most cases,
after you physically install new hardware and restart, the operating system
automatically recognizes the hardware and installs the device’s drivers. Each time a
computer starts up, the device drivers for all its connected peripherals are loaded into
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