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Guide to Networking Essentials, Fifth Edition
Chapter 4
Network Interface Cards
At a Glance
Instructor’s Manual Table of Contents

Overview

Objectives

Teaching Tips

Quick Quizzes

Class Discussion Topics

Additional Projects

Additional Resources

Key Terms

Technical Notes for Hands-On Projects
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Lecture Notes
Overview
Chapter 4 offers an introduction to network interface cards (NICs). Students learn about
a NIC’s function and configurable options, as well as how to select an appropriate
network adapter. They also learn about the special-purpose NICs and the role of driver
software in network adapters.
Objectives
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Describe a network interface card’s function and configurable options
List important factors for selecting network adapters
Describe types of special-purpose network interface cards
Explain the role of driver software in network adapters
Teaching Tips
Network Interface Cards (NIC) Basics
1. Explain the role of a NIC (basically, establishing a link between a computer and a
network, and then managing that link).
Teaching
Tip
Read more about network cards at:
http://en.wikipedia.org/wiki/Network_interface_card.
From Parallel to Serial and Vice Versa
1. Use Figure 4-1 to explain why a NIC needs to redistribute data coming serially to
parallel lines, and vice versa. Don’t forget to introduce the terms computer bus, parallel
transmission, serial transmission, buffer, and bus width.
Teaching
Tip
The process of translating data bits that a computer generates into a suitable form
for the network medium is called encoding. Encoding is covered in greater detail
in Chapter 5.
2. Use Figure 4-2 to describe the components of an Ethernet NIC. Don’t forget to
introduce the terms ISA, adapter slot, and PCI.
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Teaching
Tip
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Read more about computer buses at: http://en.wikipedia.org/wiki/Computer_bus.
Additional Functions of a NIC
1. Explain each of the additional functions of a NIC:
a. Create, send and receive frames.
Teaching
Tip
Stress that the term “packet” is often used to describe the unit of information sent
between network devices, but “frame” is more accurate when discussing the unit
of information the NIC handles.
b. Deal with frame-level errors and incomplete or unintelligible frame structures.
c. Manage access to medium.
d. Act as gatekeeper (describe the role of the MAC address and the card’s
promiscuous mode).
Teaching
Tip
Explain that the address on a NIC is called the MAC address because the NIC’s
Media Access Control functions handle it. These addresses take the form of six
two-digit hexadecimal numbers separated by colons—for example,
00:60:97:33:90:A3 is a MAC address. The first three numbers identify the
manufacturer; the second three numbers define a unique address assigned to the
NIC.
Teaching
Tip
Read more about MAC addresses at: http://en.wikipedia.org/wiki/MAC_address.
PC Buses
1. Explain that when PCs were introduced, only a single bus design existed: a limited 8-bit
bus. Briefly describe each of the other buses that were developed later. See Table 4-1
for a quick summary of the characteristics of each of the bus types.
2. Don’t forget to introduce the terms IRQ, Cardbus (see Figure 4-5), and ExpressCard.
Teaching
Tip
Read more about PC cards at: http://en.wikipedia.org/wiki/PCMCIA.
3. Stress that most computer systems today come with two to six PCI (or PCI-X) slots and,
more frequently, one or more PCI Express slots.
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4. Note that current computer ads show that the most popular buses for desktop machines
and network servers are PCI, PCIe, and PCI-X (see Figures 4-3 and 4-4).
Teaching
Tip
Stress that for network servers, where fast network access is a key component in
network performance, you should use 64-bit PCI-X or PCIe NICs when possible.
Because traffic aggregates at the server, spending extra money on a faster NIC
pays for itself quickly.
Other PC Interfaces Used for Networking
1. Explain that the USB and FireWire (IEEE 1394) interfaces can also be used to connect
NICs to PCs. Briefly describe the characteristics of each of these interfaces (including
the differences between versions).
Teaching
Tip
Read more about USB and FireWire at http://en.wikipedia.org/wiki/USB and
http://en.wikipedia.org/wiki/FireWire, respectively.
Principles of NIC Configuration
1. Explain the role of PnP in NIC configuration. Don’t forget to introduce the term poweron self test (POST).
2. Explain that NIC configuration involves working with the following settings:
a. Interrupt request line (IRQ)
b. Base I/O port
c. Base memory address
Teaching
Tip
Note that today’s operating systems and PCI-bus PnP NIC cards make manual
configuration largely unnecessary. However, older NICs or OSs might require
manual configuration from time to time. For more details on expansion card
configuration, see the A+ Guide to Managing and Maintaining Your PC, 5th
Edition (Course Technology, ISBN 1-4188-3557-9).
Integrated NICs
1. Explain that most PC motherboard and laptop computer manufacturers integrate the
network interface directly on to the motherboard (on-board NIC).
2. Explain why an on-board NIC might not meet a user’s need (wrong media, speed, or
architecture).
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Making the Network Attachment
1. Remind students of the several vital roles that NICs perform to coordinate
communications between computer and network.
2. Explain that matching the adapter you choose with the medium it must attach to is
essential.
3. Note that some NICs support multiple media types, and configuration is usually
automatic or performed by using SW
Quick Quiz 1
1. What is an adapter slot?
Answer: An adapter slot is a socket built into PC motherboards that are designed to
accommodate add-on cards, such as NICs.
2. Each card has a unique identifier, called a(n) ____________________ (MAC) address,
in the form of data programmed on to read-only memory (ROM) on the interface.
Answer: Media Access Control
3. Current computer ads show that the most popular buses for desktop machines and
network servers are PCI, PCIe, and ____________________.
Answer: PCI-X
4. What is PnP?
Answer: In an effort to make the task of configuring computer hardware easier,
Microsoft introduced Plug and Play (PnP) architecture with Windows 95. PnP attempts
to define a set of configuration protocols so that a computer can communicate with its
peripherals during the power-on self test (POST) sequence and negotiate a working
configuration without requiring user intervention. In other words, you plug it in, and it
works.
Choosing Network Adapters for Best Performance
1. Explain the importance of choosing network adapters for best performance, especially
in servers.
2. Describe each of the following hardware-enhancement NIC options:
a. Direct Memory Access (DMA)
b. Shared adapter memory
c. Shared system memory
d. Bus mastering
e. RAM buffering
f. On-board co-processors
g. Various security options
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Traffic management (Quality of Service (QoS))
Automatic link aggregation
Improved fault tolerance
Improved management features
3. Stress that increased performance features have payoffs for servers that might not apply
to workstations. Describe the best choices for each of the following NIC characteristics
(when an increased performance is desired):
a. Bus width
b. Bus type
c. Memory transfer
d. Special features
e. Bus mastering
f. Vendor factors
Special-Purpose NICs
1. Explain that special-purpose NICs include interfaces for wireless networks, as well as a
feature for so-called diskless workstations (also called “thin clients”), which must
access the network to load an OS when they boot.
Wireless Adapters
1. Explain that wireless interfaces (see Figure 4-6) usually incorporate some or all of the
following components:
a. Indoor antenna and antenna cable
b. Software to enable the adapter to work with a particular network environment
c. Diagnostic software
d. Installation software
2. Note that wireless NICs are commonly used with a wireless access point to add wireless
elements to an existing wired network.
3. Explain that when choosing a wireless NIC, you should select the appropriate speed,
wireless standard, and advanced options (e.g., security).
Remote Boot Adapters
1. Explain the role of remote boot adapters. Introduce the terms diskless workstation and
Boot PROM.
2. Briefly describe the advantages of remote booting adapters (mainly, reduced costs,
improved reliability, and increased security).
Driver Software
1. Explain what a device driver is.
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2. Stress that incorrect drivers or poorly written drivers can have detrimental impact on
performance or prevent the PC from booting.
3. Briefly describe each of the major standards for drivers: NDIS, WDM, and ODI.
4. Note that installing a driver for a NIC is usually easy.
5. Use Figure 4-7 to briefly describe (an example of) the process of network adapter driver
installation.
Teaching
Tip
Note that although driver installation for NICs on modern OSs is fairly
straightforward, it hasn’t always been. Windows NT, for example, provides
limited support for NICs during installation and often doesn’t recognize a NIC.
This limitation can cause problems for novice installers of NT. Having the NIC
drivers available on disk during NT installation is essential.
6. Explain that large vendors have a searchable database of problems and their solutions in
a knowledge base, where you can enter a keyword or an error code to search for
information.
NIC Driver Configuration
1. Use Figure 4-8 to briefly describe (an example of) the process of network adapter driver
configuration.
2. Briefly explain why you may want to change the MAC address of a NIC (see Figure 48).
3. With respect to the “Speed/duplex” settings, explain that, typically, the driver is set for
a mode called autonegotiation, which lets the driver work out the optimal connection
type with the device the NIC is connected to. In rare cases, however, autonegotiation
doesn’t work, and a manual setting is called for.
4. Use Figure 4-9 to describe the role of the “Driver” tab.
Wireless NIC Configuration
1. Use Figure 4-10 to describe the process of configuring a wireless NIC. Describe the role
of an SSID in a wireless NIC configuration.
Teaching
Tip
Read more about SSIDs at: http://en.wikipedia.org/wiki/Service_set_identifier.
2. Explain that the wireless client will probably need to enter a network key, or encryption
keycode, which acts like a password to allow entry to the wireless network. Figure 4-11
shows a client connecting to the CNT-APG network and entering the required keycode.
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Quick Quiz 2
1. Diskless workstations (also called “____________________ clients”), must access the
network to load an OS when they boot.
Answer: thin
2. The IEEE has ratified a wireless security standard based on WPA called
____________________.
Answer: 802.11i
3. What is a device driver?
Answer: A device driver is a small, specialized program that represents a device to an
OS and manages communications between the OS and network adapter.
4. Large vendors have a searchable database of problems and their solutions in a(n)
____________________, where you can enter a keyword or an error code to search for
information.
Answer: knowledge base
Class Discussion Topics
1. Have any of the students installed or configured a NIC? If so, ask them to discuss their
experiences in class.
2. Do students know (some of) the characteristics of the NICs installed in their personal
computers or laptops? If so, ask them to describe them in class.
Additional Projects
1. Ask students to compile a list of NIC prices. The list should include NICs with different
characteristics and from different vendors.
2. Ask students to use Ethereal (www.ethereal.com) to examine the contents of the frames
received by a NIC. They should not analyze higher layer packets at this point. Ask them
to concentrate on analyzing frames. According to the captured frames, what is the
format of an Ethernet frame?
Additional Resources
1. Network Card:
http://en.wikipedia.org/wiki/Network_interface_card
2. MAC Address:
http://en.wikipedia.org/wiki/MAC_address
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3. Computer Bus:
http://en.wikipedia.org/wiki/Computer_bus
4. PC Card:
http://en.wikipedia.org/wiki/PCMCIA
5. Universal Serial Bus:
http://en.wikipedia.org/wiki/USB
6. FireWire:
http://en.wikipedia.org/wiki/FireWire
7. Wireless Network Interface Card:
http://en.wikipedia.org/wiki/Wireless_network_interface_card
8. Service Set Identifier:
http://en.wikipedia.org/wiki/Service_set_identifier
Key Terms
 adapter slot — The sockets built into a PC motherboard that are designed to
accommodate add-on cards, such as NICs. See also Industry Standard Architecture
(ISA) and Peripheral Component Interface (PCI). (Both are specific types of adapter
slots.)
 automatic link aggregation — A feature of some NICs that adds the bandwidth of two
installed NICs together, resulting in a higher aggregate bandwidth.
 autonegotiation — The process by which a NIC driver automatically selects an
operating mode (speed and duplex mode). To make this selection, the NIC driver
negotiates the optimal connection type with the device the NIC is connected to.
 Boot PROM — A special programmable chip that includes enough software to permit
a computer to boot sufficiently and access the network. From there, it can download an
operating system to finish the boot process. Also known as PXE compliant.
 boot up — The process a computer goes through when starting; also called booting.
 buffer — A temporary storage area that a device uses to contain incoming data before it
can be processed for input, or to contain outgoing data before it can be sent as output.
 bus mastering — The capability of an adapter card’s circuitry to take possession of a
computer’s bus and coordinate data transfers without requiring any service from the
computer’s CPU.
 bus width — The number of parallel lines that make up a type of bus. For example,
ISA supports 8- and 16-bit bus widths, and PCI supports 32- and 64-bit bus widths.
 Cardbus — A credit-card-size expansion card used primarily to add functionality to
laptop computers. Cardbus provides data transfer rates up to 132 MBps. See also
ExpressCard.
 computer bus — A specialized collection of parallel lines in a PC used to transfer data
between the CPU and peripheral devices and occasionally from one peripheral device to
another.
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 device driver — A software program that mediates communication between an
operating system and a device for the purpose of sending and receiving input and output
from that device. These drivers are operating system dependent. They also need to be
kept up to date per information on the manufacturer’s Web site.
 diagnostic software — Specialized programs that can probe and monitor a system (or
system component) to determine whether it works and, if not, try to establish the cause
of the problem.
 direct memory access (DMA) — A technique for addressing memory on some other
device as though it were local memory directly available to the device accessing that
memory. This technique lets a CPU gain immediate access to the buffers on any NIC
that supports DMA.
 diskless workstations — Network computers that require a special type of ROM
because they have no built-in disk drives.
 ExpressCard — A credit-card-size expansion card used primarily to add functionality
to laptop computers. ExpressCard provides data transfer rates up to 500 MBps. See also
Cardbus.
 fault tolerance — A feature that allows a system to continue working after an
unexpected hardware or software failure.
 FireWire — A high-speed, external serial bus that supports bandwidths up to 400 Mbps
and can connect up to 63 devices; also known as IEEE 1394. FireWire is used for
streaming video and multimedia, networking, and attaching video devices to computers.
 hexadecimal — A mathematical notation for representing numbers in base 16. The
numbers 10 through 15 are expressed as A through F; 10h or 0x10 (both notations
indicate the number is hexadecimal) equals 16.
 Industry Standard Architecture (ISA) — Originally an 8-bit PC bus architecture, but
upgraded to 16-bit with the introduction of the IBM PC/AT in 1984.
 interrupt request (IRQ) line — Any of 16 unique signal lines between the CPU and
bus slots on a PC. IRQs define the mechanism whereby a peripheral device of any kind,
including a network adapter, can stake a claim on a PC’s attention. This claim is called
an “interrupt,” so the lines carrying this information are called “interrupt request lines.”
 keycode — A string of characters that a user must supply to wireless NIC software so
that the computer can decrypt communications on a wireless LAN, therefore allowing
the client to access the LAN.
 knowledge base — A searchable online database containing problems and errors, along
with their solutions, related to a manufacturer’s product.
 Media Access Control (MAC) address — The number that identifies the physical
address of a network computer. This address is burned into the computer’s NIC in the
form of data programmed on to the interface’s ROM.
 Network Device Interface Specification (NDIS) — A driver standard for providing an
interface between a network interface card and the network medium; this standard
enables a NIC to use multiple protocols.
 network interface card (NIC) — The hardware device that mediates communication
between a computer and the networking medium.
 on-board co-processor — A special- or general-purpose microprocessor on an adapter
card, usually for offloading data from a computer’s CPU. Typically, NICs with onboard co-processors use the special-purpose variety.
 on-board NIC — The electronics that make up a network interface integrated directly
onto a computer motherboard.
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 Open Data-link Interface (ODI) — A specification developed by Apple Computer
and Novell that simplifies driver development and enables a single NIC to use multiple
protocols.
 parallel transmission — The technique of spreading bits of data across multiple
parallel data lines to transmit them simultaneously, instead of according to an ordinal
and temporal sequence.
 PCI Express — A high-speed bus standard that relies on serial communications
arranged in lanes to provide communications up to 8 GBps.
 PCI-X — A high-speed bus standard that supports 64 bits at 66 MHz up to 533 MHz
for .5 GBps to more than 4 GBps data transfer rates.
 PCMCIA cards — Credit-card-size expansion cards used primarily to add
functionality to laptop computers. Two standards are in common use. See also Cardbus
and ExpressCard.
 Peripheral Component Interconnect (PCI) — The 32- and 64-bit PC bus architecture
that currently prevails as the best and fastest of all available bus types, operating at 33
and 66 MHz.
 Plug and Play (PnP) — The Microsoft requirements for PC motherboards, buses,
adapter cards, and operating systems that enable a PC to detect and configure hardware
on a system automatically. For PnP to work, all system components must conform
rigorously to its specifications; currently, Windows 9x, 2000, XP, 2003, and Vista
support this architecture.
 power-on self test (POST) — The set of internal diagnostic and status-checking
routines a PC and its peripheral devices run each time the computer is powered on.
 Quality of Service (QoS) — A networking term that specifies a guaranteed level of
service when applied to applications requiring high bandwidth.
 RAM buffering — A memory-access technique that permits an adapter to use a
computer’s main memory as though it were local buffer space.
 serial transmission — A technique for transmitting data signals that sends each bit’s
worth of data (or its analog equivalent) one at a time, one after another, in sequence.
 service set identifier (SSID) — The name assigned to a wireless LAN.
 shared adapter memory — A technique for a computer’s CPU to address memory on
an adapter as though it were the computer’s own main memory.
 shared system memory — A technique for an adapter to address a computer’s main
memory as though it resided on the adapter.
 traffic management — In terms of NICs, features that improve network accessibility
for remote users, especially those using applications that require higher bandwidth, such
as streaming video or multimedia.
 Universal Serial Bus (USB) — A hot-pluggable Plug and Play serial interface; USB
ports support peripheral devices, such as mouses and keyboards, in addition to some
printers, scanners, telephony equipment, and monitors. USB 1.0 operates at a maximum
data transfer rate of 12 Mbps; USB 2.0 supports up to 480 Mbps.
 Win32 Driver Model (WDM) — A unified driver standard that allows a single driver
to be written for any 32-bit version of Windows (those since Windows 98).
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Technical Notes for Hands-On Projects
Hands-On Project 4-1: This project requires a variety of NICs with different bus types that
accommodate different cabling, each labeled with a different number.
Hands-On Project 4-2: This project uses Windows XP but can be adapted to Windows Vista,
Windows 2000, or Windows 9x with some adjustments.
Hands-On Project 4-3: This project requires a Web browser and Internet access.
Hands-On Project 4-4: This project requires some common networking diagnostic tools in
Windows XP: getmac, ipconfig, net view, ping, and arp.
Hands-On Project 4-5: This project requires Windows (Control Panel  Network and Internet
Connections  Network Connections  Local Area Connections  Properties).