Unit 2 Local Area Networks (LANs) Networking.pdf

LAN

1. UNIT 2 : Local Area Networks (LANs)
IT45103
NETWORKING
Networking 1

2. Introduction
2
A local area network is a communication
network that interconnects a variety of data
communicating devices within a small
geographic area and broadcasts data at high
data transfer rates.
Since the local area network first appeared in
the 1970s, its use has become widespread in
commercial and academic environments
Networking

3. Primary Function of Local Area Networks
3
To provide access to hardware and software
resources that will allow users to perform one
or more of the following activities:
File serving
◼A large storage disk drive acts as a central
storage
Print serving
◼Provides access to a shared printer, accepts and
queues print jobs, and provides a user access to
the print queue
Networking

4. Primary Function of Local Area Networks
(continued)
4
Video transfers
◼High speed LANs are capable of supporting video
image and live video transfers
Manufacturing support
◼LANs can support manufacturing and industrial
environments
Academic support
◼In classrooms, labs, and wireless
E-mail support
Interconnection between multiple systems
Networking

5. 5
A local area network interconnecting another local area
network, the Internet and a mainframe computer
Networking

6. Advantages and Disadvantages of
Local Area Networks
6
Advantages
Ability to share hardware and software
resources
Secure, reliable transfers at high speeds
Component and system evolution are
possible
Support for different types of hardware and
software
Access to other LANs and WANs
Networking

7. Advantages and Disadvantages of
Local Area Networks (continued)
7
Disadvantages
Equipment and support can be costly
Level of maintenance continues to grow
Some types of hardware/software may not
interoperate well
LAN is only as strong as its weakest link, and
there are many links
Networking

8. UNIT 2 : Local Area Networks (LANs)
IT45103
NETWORKING
Networking 8

9. Introduction
9
Popular local area network today – star
wired bus.
Logical design – determines how data
moves around the network.
Physical design – the pattern formed by
the locations of the elements of the
network, as it would appear if drawn on
sheet of paper.
Networking

10. A More Modern LAN –The Star-Wired Bus
10
Logically operates as a bus, but physically looks like
a star
Star design is based on hub
All workstations attach to hub
Unshielded twisted pair usually used to connect
workstation to hub
Originally, hub takes incoming signal and immediately
broadcasts it out all connected links
Hubs can be interconnected to extend size of network
Networking

11. Star-Wired Bus (continued)
Networking
11

12. Star-Wired Bus (continued)
12
Advantage – simple installation and maintenance, low
cost components and high volume of compatible
products.
Modular connectors and twisted pair make
installation and maintenance of star-wired bus
better than standard bus
Hubs can be interconnected with twisted pair, coaxial
cable, or fiber-optic cable
Biggest disadvantage = when one station talks,
everyone hears it
This is called a shared network
◼All devices are sharing the network medium
Networking

13. 13
In practice, all modern networks use switches
instead of hubs
Like hubs, used to interconnect multiple
workstations on a single LAN or to interconnect
multiple LANs.
The switch acts as a filter.
Reduces the amount of traffic on the
interconnected networks by only sending data
to the required ports
Star-Wired Bus (continued)
Networking

14. Star-Wired Bus (continued)
Networking
14

15. Medium Access Control Protocols
15
If using a hub, how does a workstation get its
data onto the LAN medium since the medium is
shared?
A medium access control protocol is the software
that allows workstations to “take turns” at
transmitting data
Two basic categories:
Round-robin protocols
◼Everyone gets a turn
Contention-based protocols
◼First-come, first-served
Networking

16. Contention-Based Protocols
16
Most common example is carrier sense multiple
access with collision detection (CSMA/CD)
If no one is transmitting, workstation can
transmit
If someone else is transmitting, workstation
“backs off” and waits for a random time
Networking

17. Contention-Based Protocols (continued)
17
If two workstations transmit at same
time, collision occurs
When two workstations hear collision,
they stop transmitting immediately
Each workstation backs off a random
amount of time and tries again
Hopefully, both workstations do not try
again at exact same time
Networking

18. UNIT 2 : Local Area Networks (LANs)
IT45103
NETWORKING

19. Wired Ethernet
Most common form of LAN today
Star-wired bus is most common physical
topology but logical bus topology still not
totally dead yet
Comes in many forms depending upon
medium used and transmission speed and
technology
Networking
2

20. Wired Ethernet (continued)
Originally, CSMA/CD Ethernet was 10
Mbps
Then 100 Mbps was introduced
Most NICs sold today are 10/100 Mbps
1000 Mbps (1 Gbps) is now on many PCs
10 Gbps is being used in high-end
applications
Networking
3

21. Wired Ethernet (continued)
Networking
4

22. UNIT 2 : Local Area Networks (LANs)
IT45103
NETWORKING

23. Introduction
A local area network that is not based
primarily on physical wiring but uses wire-
less transmissions between workstations is
a wireless LAN, or wireless Ethernet.
Strongest advantages of a wireless LAN is
that there is no cabling
Networking
6

24. Basic components of Wireless LAN
A few basic components are:
The user device (also called the wireless
station)
The wired local area network
The access point (AP), or wireless router,
which is the component that communicates
with the wireless user device.
7
Networking

25. Wireless LAN basic configurations
Basic Service Set (BSS)
The single-cell wireless LAN as used in most
home installations
At the center of the cell is the access point,
which is connected to the wired LAN.
All user devices communicate with this one
access point and use the same set of
frequencies.
8
Networking

26. Basic Service Set (BSS)
9
Networking

27. Extended Service Set (ESS)
Multiple-cell layout
Used in colleges and other large buildings
In this configuration, multiple cells are
supported by multiple APs, as in a cellular
telephone network.
User devices communicate with the nearest
AP and may move from one cell to another.
10
Wireless LAN basic configurations
Networking

28. Extended Service Set (ESS)
11
Networking

29. Peer-to-peer, or ad hoc
layout
With this configuration,
there is no access point at
the center of a cell.
Each user device
communicates directly with
the other user devices.
Supported by most mobile
phones and Windows 10
as “Mobile Hotspot”
12
Wireless LAN basic configurations
Networking

30. Wireless LAN protocol
IEEE 802.11 suite of protocols was created to
support the many different types of wireless local
area networks.
These have recently been given more user-friendly
names WiFi 1 – WiFi 6
 Different types of physical layer connections:
Infrared transmissions. No longer commonly used
Spread spectrum. Used by the earlier WiFi standards
802.11a and b
OFDM(Orthogonal frequency division multiplexing). Used by later standards
13
Networking

31. Other IEEE wireless LAN protocols
IEEE 802.11a, (WiFi 1) is capable of supporting a theoretical rate of 54-
Mbps transmissions using the 5-GHz frequency range.
IEEE 802.11b, (WiFi 2) transmits data at a theoretical rate of 11 Mbps
using 2.4-GHz signals.
IEEE 802.11g, (WiFi 3) transmits data at a theoretical rate of 54 Mbps
using the same 2.4GHz frequencies used in 802.11b.
IEEE 802.11n, (WiFi 4) maximum data rate of 600 Mbps with actual data
rates of roughly 120 Mbps. Uses a multiple antenna technology called
multiple input multiple output (MIMO).
IEEE 802.11ac, (WiFi 5) maximum data rate of 3400 Mbps with actual
data rates of roughly 250Mbps. Also uses MIMO.
IEEE 802.11ax, (WiFi 6) maximum data rate of 9600 Mbps with actual
data rates of roughly 2000 Mbps. Uses more advanced MIMO techniques.
14
Networking

32. Wireless Hardware
Wireless router
The central point of any Wi-Fi network or base station.
Several key functions:
◼Creates the wireless Wi-Fi network
◼Serves as a Wi-Fi hot spot to share your Internet connection
wirelessly.
◼Offers several Ethernet ports to connect computers directly
(nonwirelessly) to the device (LAN ports)
◼Routes signals and data from your network to the internet (WAN
port).
◼Provides firewall functionality to protect your network from outside
attack.
◼Many recent models come with a USB port to allow operation as a
file server
15
Networking

33. Wireless router
16
Networking

34. Wireless Network Interface Card (NIC)
The wireless NIC, using the various 802.11
protocols, transmits data to the AP.
Most often associated with mobile devices,
such as laptop computers and mobile phones.
Not normally visible, because there is no
requirement to connect a cable to it.
Antenna is normally built into the device also.
17
Wireless Hardware (cont..)
Networking

35. Wireless Network Interface Card
(NIC)
NICs
for
various
older
devices
and for
desktop
PCs
18
Networking

36. Wireless adapter
Wireless adapter installed on desktop computer in
order to join wireless network.
It’s a PCI card with antenna which can be inserted to
computer motherboard
USB wireless adapter can be used on desktop PCs or
on laptops.
PCMCIA card devices insert into a slot on the side of
older notebook computers.
19
Wireless Hardware (cont..)
Networking

37. Wireless Access Point
Access points act as a central transmitter and receiver
of WLAN radio signals.
Used in home or small business networks but usually
built in to router
Older access points allowed a maximum of only 10 or
20 clients;
Many newer access points support up to 255 clients.
Standalone Access Points are now commonly sold as
Range Extenders for larger homes and offices
20
Wireless Hardware (cont..)
Networking

38. Wireless Access Point
21
Networking

39. UNIT 2 : Local Area Networks (LANs)
IT45103
NETWORKING

40. Introduction
A network operating system (NOS) is a large,
complex program that can manage the common
resources on most local area networks, in addition to
performing the standard operating system services:
client OS such as Windows 10 can perform many
networking functions
Besides performing standard OS functions, a network
OS is called upon for additional functions, such as:
2

41. 3

42. Pioneer of network operating systems
Novell Netware
4
At one time NetWare was the leading local area
network OS
Has been discontinued by Novell and replaced
by their Linux based Open Enterprise Server
Nonetheless, it was NetWare that introduced a
number of very powerful concepts, including the
hierarchical directory structure

43. Novell NetWare (continued)
Version 3
No longer supported by Novell (end of 2000)
User logs onto a particular server
Version 4
No longer supported by Novell (beginning of 2004)
Unlike version 3 this version allows single network login
Version 5 (1998)
Used IP protocol instead of Novell’s IPX/SPX protocols
Version 6 (2001)
Final version
Was supported until 2017
5

44. 6
Current Network Operating Systems
Several popular network OSs currently exist:
Windows Server family
Unix
Linux
MAC OS X Server

45. Windows NT Version 4
User interface based on popular Windows OS
Was NOT same as Windows 98 which was the
supported client OS at that time
Full service multitasking OS capable of supporting
multiple servers
NT systems worked very well with other Microsoft
products
7

46. Windows NT Version 4 (cont..)
Domain
Group of users, servers, and other resources that share
account and security information
May have from 1 to several hundred domains depending on
size of system
Every domain has one and only one primary domain
controller (PDC) (a server)
Centrally manages account information and security
Each domain should have at least one backup domain
controller (BDC) (a server)
8

47. Single domain model
Simplest Window NT model
All users and resources are in one domain
Multiple domain model
Multiple domains, but no hierarchy
Each domain is equal to all other domains
To allow data to transfer between domains required
the creation of trusts
9
Windows NT Version 4 (cont..)

48. 10

49. 11
Windows 2000
Updated version of Windows NT network OS
Specific versions of 2000 designed to support wide
variety of system types:
Windows 2000 Professional
◼Replaced NT Workstation
Windows 2000 Server
◼Replaced Windows NT Server
Windows 2000 Advanced Server
◼Supported up to 8 procs / 8GB
Windows 2000 Datacenter Server
◼Supported up to 32 processors and 64GB RAM

50. 12
Windows 2000 (continued)
Biggest change from NT is Active Directory (AD)
AD is central repository for all objects that make up the
enterprise: domains, organizational units, users, groups,
computers, printers, etc.
Roughly based on X.500 spec, creates a hierarchical
tree

51. 13
Windows 2000 (continued)
At the top of hierarchical model is single forest of
one or more trees, which must contain at least one
(root) domain, which must contain at least one
organizational unit (OU), and several other
containers
Recommended size limitation of 1 million objects
per domain, but lab tests have hit 10 million objects
without failure

52. 14
Windows 2000 (continued)

53. 15
Windows 2003
Improvements to Active Directory, including new
management tools
Capability to interconnect up to 8 Windows servers
New and improved file and print support services
Support for IPv6
Security improvements

54. 16
Windows 2008
Continued improvements to Active Directory,
including new management tools
New server core (including a virtual server)
Self-healing server that can fix corrupted files
and/or folders
Increased processing speed
Advancements in network security
Support stopped in Jan 2020

55. 17
Windows 2019
The current version of Windows network OS
Continued improvements to Active Directory
Support for Microsoft cloud service Azure
Manages virtual machines
Works with Virtual networks
Improved support for Linux and other network
systems

56. Windows 2022
Windows Server 2022 brought several new
features and improvements over its predecessor,
Windows Server 2019.
The new Windows Server is Microsoft's most
reliable, secure, and Azure-compatible OS. With
Windows Server 2022, organizations get advanced
security features and improved cloud integration
that helps protect their data from malicious actors.
This couldn't come at a better time, as cyber threats
and data security risks rapidly increase.
18

57. 19
Unix
Older but very popular multitasking OS capable of
supporting network operations
First OS written in the language C
Very stable system capable of supporting very
large operations
Numerous versions available from different vendors

58. 20
Linux
OS based on the principles of Unix.
Many versions available for free or very small price
Very stable multitasking OS
When incorporated with other free software
products, such as the Apache Web server and
Atipa’s BlueBird network management software, this
system becomes extremely cost effective and
powerful

59. Novell Linux
Novell, seeing that its market share of NetWare
was eroding, moved into the Linux market in the
early 21st century
Branded as Open Enterprise Server
Novell currently offers a number of versions of Linux,
including high-power servers and desktop OSs
21

60. 22
Mac OS X Server
Apple Computer finally joined the NOS market with
its Mac OS Server
Version X is based on Linux code
Very stable and quite powerful
While installed primarily in Apple networks, Mac
OS X Server is also capable of supporting non-
Apple networks

61. 23

62. 24
Summary of Network Operating
Systems

63. UNIT 2 :
Local Area Networks (LANs)
IT45103
NETWORKING

64. Microsoft Active Directory User accounts are
the link between real people and network
resources in a corporate Windows network.
User accounts have two main functions:
▪Provide a method for users to authenticate
themselves to the network
▪Using a username and password to log on to a network
▪Provide detailed information about a user
▪Hold detailed information such as user’s phone number,
office location and so forth for use in a company.
Copyright © 2012 Cengage Learning. All rights reserved. 2
MANAGING USER AND GROUP ACCOUNTS

65. Group accounts are used to organize users
so that assignment of resource permissions
and rights can be managed more easily than
working with dozens or hundreds of
individual user accounts
▪Example: Group users by department within a
company. When a shared folder containing
documents used by a certain department is created,
the admin just needs to assign permissions to the
whole group.
Copyright © 2012 Cengage Learning. All rights reserved.
MANAGING USER AND GROUP ACCOUNTS

66. In a large network with many servers and
hundreds or thousands of users, a scheme for
naming user and group accounts as well as
network devices is critical. Consider the
following:
▪Is there a minimum and maximum number of characters
user account names should have?
▪Should the username be based on the user’s real name
or if security is important, should names be more
secret?
▪Some OSs differentiate between uppercase and
lowercase letters. Should usernames contain both as
well as special characters?
Copyright © 2012 Cengage Learning. All rights reserved. 4
MANAGING USER AND GROUP ACCOUNTS

67. Considerations for password conventions:
▪Minimum length: longer passwords harder to guess, more secure
▪Complexity requirements: use of uppercase and lowercase along
with special characters (such as @, $, %)
▪User or administrator created
▪Password change frequency to enhance security.
▪However over complex requirements can damage security because
users may store them insecurely
Group account names should reflect the group membership
(such as a department name) or the resource to which the
group is assigned permissions
Copyright © 2012 Cengage Learning. All rights reserved. 5
NAME AND PASSWORD CREATION

68. When Windows is first installed, two users are
created
▪Administrator and Guest (usually disabled)
The Administrator account has full access to a
computer
Windows domain users are created in Active
Directory Users and/or Computers
You can create folders for organizing users
and groups (called organization units or OUs)
Copyright © 2012 Cengage
Learning. All rights reserved.
6
WORKING WITH ACCOUNTS IN WINDOWS

69. Active Directory Users and Computers
Copyright © 2012 Cengage Learning. All rights reserved. 7
WORKING WITH ACCOUNTS IN WINDOWS

70. To create a new user:
✓Open the folder where you
want to create the user.
✓Right-click the folder, point
to New, and click User.
✓The New Object – User
Dialog box opens
✓**Everything you create in
Active Directory is
considered an object.
Copyright © 2012 Cengage Learning. All rights reserved. 8
WORKING WITH ACCOUNTS IN WINDOWS
Note that details of user creation etc. vary with different versions of Windows

71. Setting the password and additional account options
Note – After a user account is created, you can double
click it to open its properties
Copyright © 2012 Cengage Learning. All rights reserved. 9
WORKING WITH ACCOUNTS IN WINDOWS

72. Creating a new group in Active Directory
Copyright © 2012 Cengage Learning. All rights reserved. 10
CREATING GROUP ACCOUNTS
IN WINDOWS DOMAINS

73. UNIT 2 :
Local Area Networks (LANs)
IT41113
NETWORKING

74. Network administrators need to:
▪Make sure enough storage space is
available to store files needed
▪Manage who has access to file storage
▪Prevent users from storing inappropriate
types of data on company servers
Locally attached storage
▪A device, such as a hard disk, that is connected to
a storage controller on the server
Copyright © 2012 Cengage Learning. All rights reserved. 12
STORAGE AND FILE SYSTEM
MANAGEMENT

75. Copyright © 2012 Cengage Learning. All rights reserved. 13
VOLUMES AND PARTITIONS
A volume is part or all of the space on one or more disks that
contains (or is ready to contain) a file system
▪In Windows, volumes are usually assigned a drive letter
▪In Linux, volumes are mounted in the file system and accessed
as though they were a folder.
▪There is no concept of drive letters in Linux
The term partition is sometimes used interchangeably with
volume but they don’t always describe the same thing
▪In Windows, a basic disk can be divided into one to four
partitions
▪A primary partition can be formatted with a file system and
assigned a drive letter (considered a volume)
▪An extended partition can’t be formatted with a file system or
assigned a drive letter. It is divided into one or more logical
drives that can be formatted and assigned a drive letter (each
one is considered a volume)

76. Only a primary partition can be the active
partition (partition that can hold boot files)
The active primary partition storing the
Windows boot loader is referred to as the
system partition
The partition or logical drive holding the
Windows OS files is called the boot partition
A dynamic disk can be divided into one or
more volumes; the term partition is not used
in this context
Copyright © 2012 Cengage Learning. All rights reserved. 14
VOLUMES AND PARTITIONS

77. The older File Allocation Table (FAT) file system
has two variations:
▪FAT16 is usually referred to as FAT and has been around
since the mid-1980s and is supported by most OSs
▪FAT32 arrived with the release of Windows 95 OSR2 in 1996
FAT16 is limited to 2 GB partitions in most cases
FAT32 allows partitions up to 2 TB but in Windows
2000 and later, Microsoft limits them to 32 GB
because the file system becomes noticeably slower
with larger partition sizes
Most thumb drives are formatted with FAT32 since
NTFS is not supported by all systems
Copyright © 2012 Cengage Learning. All rights reserved. 15
THE FAT FILE SYSTEM

78. NTFS is a full-featured file system that Microsoft introduced
in 1993 with Windows NT
Features available in NTFS that aren’t in FAT:
Disk quotas: Limit amount of data users’ files can occupy
Volume mount points : No need for a drive letter to access the
volume
Shadow copies: Allow users to restore older file versions or
files that were accidentally deleted
File compression: Files can be stored in a compressed format
Encrypting File System: Makes encrypted files inaccessible to
everyone except the user who encrypted the file, including
users who have been granted permission to the file
Copyright © 2012 Cengage Learning. All rights reserved. 16
THE NTFS FILE SYSTEM

79. Two modes for accessing files on a networked
computer:
▪Network (sometimes called remote)
▪Interactive (sometimes called local)
Permissions can be viewed as a gatekeeper to
control who has access to folder and files
Share permissions are applied when a user
attempts network access to shared files
NTFS permissions always apply, whether file
access is attempted interactively or remotely
through a share
Copyright © 2012 Cengage Learning. All rights reserved. 17
NTFS PERMISSIONS

80. NTFS standard permissions for folders and files:
▪Read: Users can view file contents, copy files, open folders
and subfolders, and view file attributes and permissions.
▪Read & execute: Grants the same permissions as Read and
includes the ability to run applications or scripts.
▪List folder contents: This permission applies only to folders
and because it doesn’t apply to files, Read & execute must
also be set on the folder to allow users to open files in the
folder.
Copyright © 2012 Cengage Learning. All rights reserved. 18
NTFS PERMISSIONS

81. ▪Write: Users can create and modify files and read file
attributes and permissions. However, this permission doesn’t
allow users to read or delete files. In most cases, the Read
or Read & execute permission should be given with the Write
permission.
▪Modify: Users can read, modify, delete, and create files.
Users can’t change permissions or take ownership. Selecting
this permission automatically selects Read & execute, List
folder contents, Read and Write.
▪Full control: Users can perform all actions given by the
Modify permission with the addition of changing permissions
and taking ownership.
Copyright © 2012 Cengage Learning. All rights reserved. 19
NTFS PERMISSIONS (CONT’D)

82. UNIT 2 :
Local Area Networks (LANs)
IT45103
NETWORKING

83. 2
NETWORK SUPPORT SOFTWARE
In order to support a network OS, may also
need:
▪Utilities
▪Internet software

84. 3
UTILITIES
Nine of the more common groups of network utility
software include:
▪Antivirus software : designed to detect and remove viruses that
have infected your memory, disks, or operating system.
▪Anti-spam software: used to block this unwanted e-mail
▪Anti-spyware software: can locate and clean the spyware
programs found in a computer's memory and hard disk drive.
▪Backup software: allows network administrators to back up data
files currently stored on the network server's hard disk drive.

85. Crash protection software : to perform crash stalling, or to try to
keep the operating system running long enough to perform a graceful
exit.
Network-monitoring software: software that can monitor network
servers and report on CPU utilization, network activities, and server
requests.
Remote access software : allows a user to access all of the possible
functions of a personal computer workstation from a mobile or remote
location.
Security assessment software : designed to scan an IP address or
range of IP addresses for any type of security weakness .
Uninstall software: works with the user to locate and remove
applications that are no longer desired.
UTILITIES (CONT..)

86. UNIT 2 :
Local Area Networks (LANs)
IT45103
NETWORKING

87. 6
INTERNET SOFTWARE
One of the important segments of the software market is
Internet software, the tool set to support Internet-related
services. These services and applications include
▪Web browsers: allow users to download and view World Wide Web
pages.
▪Web server software : the application or set of programs that
stores Web pages and allows browsers from anywhere in the world
to access those Web pages
▪Web page publishing software: allow users to insert static
images, animated images, various forms of script, and Java-based
code into HTML files (i.e web pages).

88. 7
SOFTWARE LICENSING AGREEMENTS
Virtually every commercial software program comes with a
specific licensing agreement
Most licensing agreements specify the following conditions:
▪Software installation and use
▪Network installation
▪Backup copies
▪Decompilation
▪Rental statement
▪Upgrade availabilities
▪Copyright restrictions
▪Maintenance agreements

89. 8
SOFTWARE LICENSING AGREEMENTS
(CONTINUED)
Most licensing agreements come in one of the following
forms:
▪Single-user licences – the software package may be installed on
a single machine, and then only a single user at one time may
be using that machine.
▪Single-user-multiple-station licence – is designed for the user
who might have a desktop machine at work and a laptop machine
for remote sites, or another desktop machine at home.
▪Interactive user licences – operating system user license, and
controlled number of concurrent users license all refer to
essentially the same situation.

90. ▪System-based or network server licence – a license server
monitors the number of clients that can run the software, rather
than a license being obtained for each client
▪Site licences – allows a software package to be installed on any
and all workstations and servers at a given site.
▪Corporate licences – allows a software package to be installed
anywhere within a corporation, even if installation involves multiple
sites.
▪GPL licences – free software licence, allowing multiple copies and
also usually allowing you to modify and redistribute the software
only if you maintain the same free licence
SOFTWARE LICENSING AGREEMENTS
(CONTINUED)