Chapter 5 Network Models and Protocols - Glencoe

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Section 5.1



Explain why standards are necessary for networking



Explain how an Ethernet network functions



List Ethernet classifications


Section 5.2



Explain how a token
-
passing network functions



List wireless network classifications



Explain how wireless transmissions are sent


Section 5.3



Map TCP/IP protocols to the OSI model



Define TCP and IP



Explain IP addressing


Section 5.4



Describe the AppleTalk protocols



Explain the protocols NetBIOS and NetBEUI



Demonstrate knowledge of the NetWare protocols


pp.

136
-
141

5.1

Main Ideas


Manufacturers need
standards so their devices
can communicate with each
other. The IEEE 802.x
standards define what
happens at the Physical and
Data Link Layers. 802.3
standards are for Ethernet
networks. Ethernet networks
use a contentious means of
accessing the network called
CSMA/CD.

Key Terms


Logical Link Control (LLC)

Ethernet

contention

frame

device driver

Guide to Reading

Common LAN Models

pp.

136
-
141

5.1

IEEE 802.x

In the 1970s, the Institute of Electrical and Electronics
Engineers (IEEE) established Project 802. It defined
network standards for the physical components of a
network.

Common LAN Models

pp.

136
-
141

5.1

Project 802 standards fit
into the OSI reference
model with two
differences:




802 is limited to the
Physical and Data Link
Layers of the OSI model.




802 divides the Data Link
Layer into two sublayers



Logical Link Control
(LLC)



Media Access Control
(MAC)

Logical Link Control (LLC)

A sublayer of the Data Link
Layer that is responsible for
establishing and terminating
links to other computers and
sequencing and
acknowledging frames and
controlling frame traffic.
(p. 136)

IEEE 802.x

Common LAN Models

pp.

136
-
141

5.1

IEEE 802.x

The IEEE 802 committee defines the specifications for
LAN architectures, including:




Ethernet



Token bus



Wireless personal area networks

Common LAN Models

pp.

136
-
141

5.1

Ethernet

could be
considered the parent of
LAN technology.


An earlier network, named
ALOHA, was the first to
use CSMA/CD as its
means of controlling
network access and
contention
.

Ethernet


A LAN architecture
that uses a bus topology and
relies on CSMA/CD to
regulate traffic on the main
communication line. It uses a
bus topology and is based on
the IEEE 802.3 standard.
(p. 137)


contention


The competition
among stations on a network
for the opportunity to use a
communication line or
network resource. (p. 137)

IEEE 802.3: Ethernet Standard

Common LAN Models

pp.

136
-
141

5.1

IEEE 802.3

Many LANs rely on CSMA/CD to:




Gain access to the

network when they

have packets to

transmit.



Ensure that two

nodes do not try to

transmit at the same

time.


A collision occurs if

two computers put

data on the cable

at the same time.

Common LAN Models

pp.

136
-
141

5.1

IEEE 802.3

One drawback of
Ethernet networks is the
limited number of nodes
a network can support.
The 5
-
4
-
3 rule was
created to help maintain
network efficiency. It
specifies that there can
be no more than 5 cable
segments, 4 repeaters,
and 3 populated
segments that can exist
in any collision domain.

Common LAN Models

pp.

136
-
141

5.1

IEEE 802.3

Ethernet networks vary in topology, speed, and cabling but
have the following elements in common:




Use CSMA/CD as the means of gaining access to the network.



Are all defined in the IEEE 802.3 specifications.



Rely on broadcast transmissions that deliver signals to all
nodes at the same time.



Are primarily baseband networks.

Common LAN Models

pp.

136
-
141

5.1

Ethernet networks use a
frame

to transmit
information.


The frame ranges from 64
bytes to 1,518 bytes but are
made of the same pieces.

frame

A format that Ethernet
networks use for transmitting
data packets. The frame
contains the preamble, source
and destination addresses, data,
type of protocol used to send the
frame, and the CRC. (p. 139)

IEEE 802.3

Common LAN Models

pp.

136
-
141

5.1

Network devices use
device drivers

to allow
hardware components to
communicate to each
other.


NIC drivers provide a
virtual communication
channel between the
computer and the NIC.

device driver

Software that
helps a computer work with a
particular device. (p. 140)

Drivers and the NIC

Common LAN Models

pp.

136
-
141

5.1

You Try It






Activity 5A


Locating NIC Drivers (p. 140)

Common LAN Models

pp.

142
-
147

5.2

Main Ideas


Token
-
passing networks take
turns to gain access to the
network. Token
-
passing
networks can reliably
determine when each
computer will be able to
transmit. Wireless networks
rely on a type of contentious
access known as CSMA/CA.

Key Terms


Attached Resource
Computer Network (ARCnet)

Token Ring

Multistation Access Unit
(MAU)

Integrated Services LAN
(ISLAN)

Integrated Services Digital
Network (ISDN)

carrier sense multiple access
with collision avoidance
(CSMA/CA)

Wi Fi

Guide to Reading

Other LAN Models

pp.

142
-
147

5.2

Tokens and Token Passing

Token
-
passing
networks work like
a relay race,
passing the token
in a predetermined
order through the
network.


Only the node that
currently holds the
token is allowed to
transmit and it can
only transmit a
single packet.

Other LAN Models

pp.

142
-
147

5.2

ARCNet

was established
before the IEEE
developed the
specifications for
networks. It is popular for
smaller networks because
it is flexible and easy to
set up.

Attached Resource
Computer Network
(ARCnet)

A PC
-
based LAN
architecture that corresponds
to the IEEE 802.4
specification. An ARCnet is
built using either a bus or a
star topology. (p. 143)

IEEE 802.4 and ARCNet

Other LAN Models

pp.

142
-
147

5.2

Token Ring

is an IBM
architecture separate from
the IEEE token ring.


Token Ring relies on
nodes that are connected
to one of more hubs
called
multistation
access units (MAU)
.

Token Ring

An IBM
-
designed architecture
created to connect PC’s with
IBM’s larger midrange and
mainframe computers.
(p. 144)


Multistation Access Unit
(MAU)

The connection or
hub that forms a logical ring.
A Token Ring has a logical
ring topology. (p. 144)

IEEE 802.5 and Token Ring

Other LAN Models

pp.

142
-
147

5.2

IEEE 802.5 and Token Ring

A Token Ring network:




Typically transfers information at 1 Mbps or 4 Mbps per second
(IEEE version) or at 4 Mbps or 16 Mbps (IBM version)



Uses baseband transmission



Is based on twisted
-
pair or fiber optic cable

Other LAN Models

pp.

142
-
147

5.2

Other wired IEEE 802
specifications include:




Isochronous LAN



Integrated Services LAN
(ISLAN)



Integrated Services
Digital Network (ISDN)

Integrated Services LAN
(ISLAN)

Isochronous LANs
aimed at enabling multimedia
capabilities on a network.
(p. 145)


Integrated Services Digital
Network (ISDN)

A
technology that delivers
different types of
information

voice, data,
video

in digital form over
standard telephone cabling.
(p. 145)

Other IEEE LAN Specifications

Other LAN Models

pp.

142
-
147

5.2

Other IEEE LAN Specifications

IEEE 802.11 set standards for wireless LAN
communications. These networks are used where:




Nodes must move around freely.



Network connections are needed in a busy area.



Connections are unreliable or dependent on external factors.



It is difficult or impossible to wire the building.

Other LAN Models

pp.

142
-
147

5.2

Wireless networks use
CSMA/CA

to transmit
data through the network.


The three major variations
of wireless networking,
802.11a, 802.11b, and
802.11g are commonly
referred to as
Wi Fi
.

carrier sense multiple
access with collision
avoidance (CSMA/CA)

These nodes “listen” to the
transmission medium for a
chance to transmit. (p. 145)


Wi Fi

In wireless network
technology, the three
standards 802.11a, 802.11b,
and 802.11g are commonly
referred to as this. (p. 145)

Other IEEE LAN Specifications

Other LAN Models

pp.

142
-
147

5.2

Other IEEE LAN Specifications

At the Physical Layer, wireless LANs rely on two different
methods of transmission:




Diffused infrared light signal



Radio signals

Other LAN Models

pp.

149
-
153

5.3

Main Ideas


TCP establishes a
connection between hosts
in order to reliably
transmit data. IP relies on
a system of addresses to
locate individual hosts on
the network. IP packets
can be routed from one
network to another.

Key Terms


Transmission Control
Protocol (TCP)

Internet Protocol (IP)

Domain Name System
(DNS)

User Datagram Protocol
(UDP)

Guide to Reading

Other LAN Models

pp.

149
-
153

5.3

As more and more
companies found it
essential to “internetwork”
with other networks,
Transmission Control
Protocol/Internet
Protocol (TCP/IP)

emerged as a standard.

Transmission Control
Protocol (TCP)

A protocol
that creates a connection
between the sending and
receiving computers, and
then makes sure that all the
data arrive safely. (p. 149)


Internet Protocol (IP)

A
protocol responsible for
routing packets, sometimes
through many different
networks. (p. 149)

Introduction to TCP/IP

Other LAN Models

pp.

149
-
153

5.3

Every time you use the
Internet, you are working
with numeric IP
addresses. Your Web
browser uses a
Domain
Name System (DNS)

to
connect the domain name
to the 32
-
bit number of the
IP address.

Domain Name Server
(DNS)

Web browsers use
this to locate the IP address
of the domain name that the
user entered in the address
bar of the browser (p. 150)

Introduction to TCP/IP

Other LAN Models

pp.

149
-
153

5.3

Introduction to TCP/IP

Building on the TCP/IP stack are other protocols,
including:




File Transfer Protocol (FTP)



Telnet



Simple Mail Transfer Protocol (SMTP)



Simple Network Management Protocol (SNMP)



Hypertext Transfer Protocol (HTTP)

Other LAN Models

pp.

149
-
153

5.3

TCP/IP and OSI

TCP/IP and the OSI do not exactly match up. But each of the
TCP/IP layers correspond to one or more of the OSI layers.

Other LAN Models

pp.

149
-
153

5.3

The Transport Layer of
the TCP/IP can use either
TCP or
User Datagram
Protocol (UDP)

depending on the
requirements of the
transmission.

User Datagram Protocol
(UDP)

A connectionless
transport protocol that is
responsible for end
-
to
-
end
transmission of data. It sends
the data, but provides little in
the way of error correction.
(p. 151)


TCP/IP and OSI

Other LAN Models

pp.

149
-
153

5.3

Physical Address

Every computer in the world is assigned a unique IP
address. The address consists of two parts, a network
address and an address that identifies the node or host.


Depending on your network configuration, your IP address
may be fixed, or assigned to your computer when you boot
up.

Other LAN Models

pp.

149
-
153

5.3

You Try It






Activity 5B


Finding Your IP Address and MAC Address


Using Windows (p. 152)



Activity 5C


Finding Your IP Address and MAC Address


Using UNIX (p. 153)

Other LAN Models

pp.

155
-
158

5.4

Main Ideas


Many protocol stacks provide
services and communication
on different types of
networks. AppleTalk is used
for Macintosh networks.
Microsoft Windows
-
based
computers use the NetBIOS
interface. NetWare is
hardware
-
independent
network software that allows
networks running on different
architectures to be joined
together.

Key Terms


AppleTalk

Network Basic Input/ Output
System (NetBIOS)

NetBIOS Extended User
Interface (NetBEUI)

NetWare

Internetwork Packet
Exchange/Sequenced
Packet Exchange (IPX/SPX)

Guide to Reading

Other Models and Protocols

pp.

155
-
158

5.4

Apple Computer’s LAN
hardware and software
use a protocol stack
called AppleTalk.


AppleTalk

corresponds to
five of the seven layers of
the OSI reference model.

AppleTalk Transaction
Protocol (ATP)

A protocol in
an AppleTalk network that
transports packets. (p. 156)

AppleTalk

Other Models and Protocols

pp.

155
-
158

5.4

Most applications that run
within Windows use
NetBIOS
. It has four
primary functions.




Name Recognition



Datagram Service



Session service



NIC/session status

Network Basic
Input/Output System
(NetBIOS)

An interface that
evolved into a standard
method for applications to
access protocols in the
Transport Layer. (p. 156)

NetBIOS

Other Models and Protocols

pp.

155
-
158

5.4

Although
NetBEUI

is
small and fast, it does not
support routing. This
restricts its usefulness to
only a single segment of a
LAN.

NetBIOS Extended User
Interface (NetBEUI)

A
protocol developed by IBM in
the mid
-
1980s and was
designed for LANs of up to
200 computers. (p. 157)

NETBEUI

Other Models and Protocols

pp.

155
-
158

5.4

NETBEUI

NetBEUI was designed for small networks. On Microsoft
Windows OS, it acts as a go
-
between for the lower and
higher levels.

Other Models and Protocols

pp.

155
-
158

5.4

Novell Corporation
introduced
NetWare

early
in the development of
networking.


Internetwork Packet
Exchange/Sequenced
Packet Exchange
(IPX/SPX)

is a routable
protocol developed by
Novell that can be used
for larger networks.

NetWare

A software
networking product that runs
on top of existing hardware,
such as that used in the
Ethernet and Token Ring
networks. See also Novell
Netware. (p. 158)


Internetwork Packet
Exchange/Sequenced
Packet Exchange
(IPX/SPX)

A protocol stack
that was designed by Novell
for its NetWare networks.

(p. 158)

Netware Protocols and IPX/SPX

Other Models and Protocols

pp.

155
-
158

5.4

Netware Protocols and IPX/SPX

Notice how some of the NetWare protocols operate at
several OSI levels simultaneously.

Other Models and Protocols

Resources

For more resources on this chapter, go to the Introduction
to Networks and Networking Web site at
http://networking.glencoe.com
.

Chapter 5