Introduction to Networking

1
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Overview
Lesson 2
Lesson 3
Lesson 4
Lesson 5

• We begin by analyzing the components required for
  operation of a small peer-to-peer network.
  
• We also study how information flows between two
  computers attached to a peer-to-peer network.
  
• We move from peer-to-peer networks to
  client/server networking as we look at how
  computers and services are added to a network.

Summary
Quiz
Terms
2
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Overview
Lesson 2
Lesson 3
Lesson 4
Lesson 5

• Networks connect to other networks in a variety
  of ways.
  
• We study principles and strategies used to
  connect networks to form even larger networks.
  
• We also see how processes, protocols, and
  networking devices work together to move
  information between two computer applications.

Summary
Quiz
Terms
3
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Overview
Lesson 2
Lesson 3
Lesson 4
Lesson 5

• 1) A Small Peer-to-Peer Network
• 2) Network Servers and Services
• 3) Traffic Isolation in a Network
• 4) Connectivity to Other Networks
• 5) Information Flow from Client to Web Server

Summary
Quiz
Terms
4
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4
Lesson 5

• Peer-to-peer networks are very common in
  organizations, and are used to share resources
  between a small number of users.

Summary
Quiz
Terms
5
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4

• At the end of this lesson you should be able to
  
  
• Understand what it takes to build a small
  peer-to-peer network
  
• List the components necessary for operation of a
  peer-to-peer network
  
• List a protocol stack that can be used to
  transfer information between two clients in a
  peer-to-peer network

Objectives
Lesson 5
Summary
Quiz
Terms
Key Point

• Any computer in a peer-topeer network can
  initiatecommunication.

6
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4
Building a Peer-to-Peer Network
Lesson 5

• With a peer-to-peer network as a network,
  computers share information between each other
  and do not rely on a network server.
  
• Peer-to-peer networks exist to share resources.

Summary
Quiz
Terms
7
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4
Building a Peer-to-Peer Network (cont.)
Lesson 5

• Several components are necessary to build a
  peer-to-peer network including
  
• A computer and operating system capable of
  peer-to-peer networking
  
• Communication protocols
• A physical interface for each computer
• Physical connectivity components such as cables
  and connectors

Summary
Quiz
Terms
8
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4
Building a Peer-to-Peer Network (cont.)
Lesson 5

• A computer running Windows 95 or 98comes with
  the capability of peer-to-peer networking.
  
• Older personal computer (PC) operating systems,
  such as MS-DOS or Windows 3.1, do not have this
  capability built into the operating system.
  

Summary
Quiz
Terms
9
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4
Building a Peer-to-Peer Network (cont.)
Lesson 5

• Peer-to-peer networking is activated in the
  Windows 95 and 98 operating systems by selecting
  and installing the appropriate software
  components (such as Microsoft Client).
• Communication protocols must be loaded on the
  computer as well.
  

Summary
Quiz
Terms
10
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4
Building a Peer-to-Peer Network (cont.)
Lesson 5

• On the DialogBox Diagram, Transmission Control
  Protocol/Internet Protocol (TCP/IP) or NetBEUI
  may be used.

Summary
Quiz
Terms
11
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4
Building a Peer-to-Peer Network (cont.)
Lesson 5

• In general, with peer processes neither process
  controls the other.
  
• The same protocol is used for data flowing in
  either direction.
  
• Each of the computers proposed to share resources
  must also have a network interface card (NIC)
  installed in the computer.
  
• The NIC is used to provide the physical interface
  to other computers via cabling and a central
  wiring device.

Summary
Quiz
Terms
12
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4
Building a Peer-to-Peer Network (cont.)
Lesson 5

• Typically, cables extend from the computer NICs
  and attach to a central hub.
  
• The most common method of attaching computers in
  a peer-to-peer network is via twisted pair
  cabling (referred to as 10BaseT) attached to a
  central hub.

Summary
Quiz
Terms
13
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4
Building a Peer-to-Peer Network (cont.)
Lesson 5
Summary
Quiz
Peer-to-Peer Network
Terms
14
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4
Information Transfer in a Peer-to-Peer Network
Lesson 5

• When sending information between two peers
  directly attached, we must use identical protocol
  stacks on each client.
  
• Information sent from one computer to another
  consists of the application information and
  protocol headers used to transfer information
  from source to destination.

Summary
Quiz
Terms
15
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4
Information Transfer in a Peer-to-Peer Network
(cont.)
Lesson 5
Summary
Quiz
Ethernet Frame Going Between PCs
Terms
16
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4
Information Transfer in a Peer-to-Peer Network
(cont.)
Lesson 5

• Several protocols are used by each computer
  system to send a file from one Windows 98
  computer to another.
  
• The protocol stacks are identical in each
  machine.
  

Summary
Quiz
Terms
17
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4
Information Transfer in a Peer-to-Peer Network
(cont.)
Lesson 5

• In general, the protocols illustrated in the
  previous diagram provide the following
  
• Ethernet driver
• IP process
• TCP process
• Server Message Block (SMB)

Summary
Quiz
Terms
18
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4
Activities
Lesson 5

• 1) Draw a peer-to-peer Ethernet network
  consisting of 12 nodes using two 8-port hubs.
  Show the hubs as being daisy-chained (cascaded).

Summary
Quiz
Terms
19
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4
Activities (cont.)
Lesson 5

• Describe a typical node on this peer-to-peer
  network by answer the following
  
• 2) Describe the computer hardware (use current
  and reasonable values)
  
• a. Type and speed of CPU
• b. Amount of RAM
• c. Amount of hard disk storage
• d. Type of NIC (EISA or PCI)
• e. Type of cabling used to connect to the hub.
• f. Type of connectors on the cable.

Summary
Quiz
Terms
20
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4
Activities (cont.)
Lesson 5

• Describe a typical node on this peer-to-peer
  network by answer the following
  
• 3) Describe the software components
• a. Type of operating system
• b. Networking software installed
• c. Default protocol
• 4) Fill in the appropriate protocol stack entries
  and Ethernet frame header entries corresponding
  to the protocol stack. Assume networking software
  is TCP/IP.

Summary
Quiz
Terms
21
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4

• 1) If a lab is available, build, configure, and
  operate a peer-to-peer network.
  
• 2) Share the following resourcesbetween peers
• a. Files
• b. Directories
• c. CD-ROM
• d. Floppy drive
• e. Printers

Extended Activities
Lesson 5
Summary
Quiz
Terms
22
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements A Small
Peer-to-Peer Network
Lesson 2
Lesson 3
Lesson 4

• 3) Transfer files from the shares to other peers.
  In the case of a printer, print files to the
  print share.
  
• 4) Are there any other devices that can be
  shared? Discuss.
  
• 5) Use a Web search engine and find utilities
  available for a peer-to-peer networking
  environment. Also try www.download.com and
  www.shareware.com.

Extended Activities (cont.)
Lesson 5
Summary
Quiz
Terms
23
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4

Lesson 5

• Peer-to-peer networks are used in small
  organizations where users want to share resources
  such as files and printers.
  
• As the network grows, it may be necessary to add
  network servers and services to provide
  additional options for network users.
  

Summary
Quiz
Terms
24
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4

Lesson 5

• If it becomes burdensome to use peer computers, a
  dedicated resource may be required for both
  convenience and performance purposes.

Summary
Quiz
Terms
Database Server
25
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4

• At the end of this lesson you shouldbe able to
  
  
• Understand basic services provided by network
  operating systems (NOSs)
  
• Name common NOSs used today
• Understand the flow of information across a
  client/server network
  

Objectives
Lesson 5
Summary
Quiz
Terms
Key Point

• Services vary dependingon the installed
  software.

26
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems
Lesson 5

• Network servers, as the name implies, provide
  many different services to usersof computer
  networks.
  
• Common uses of network servers include
• File servers
• Print servers
• Communication servers
• Web servers

Summary
Quiz
Terms
27
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• File Servers
• PCs and workstations become file servers with the
  addition of specialized software.
  
• A file server makes sure that shared resources
  are accessed in an orderly, non-conflicting way.
  
  
• Servers ensure concurrent file admission when
  needed, and prevent it when inappropriate.

Summary
Quiz
Terms
28
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• File Servers (cont.)
• File servers control access through a variety of
  NOS security mechanisms
  
• NOSs vary widely in their ability toprovide
  security.

Summary
Quiz
Terms
29
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• File Servers
• A sample screen of a Windows 95 client is shown
  on the Windows 95 Client and NT Server Diagram.

Summary
Quiz
(cont.)
Terms
Windows 95 Client and NT Server
30
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• File Servers (cont.)
• This screen shot shows connectivity between a
  client and two servers.
  
• Westnetserver1 is a Windows NT server containing
  files shared by users of the network.
  
• Network drives are mapped to each client that has
  rights to access the NT server, directories, and
  files on the server.
  

Summary
Quiz
Terms
31
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• File Servers (cont.)
• By clicking the icon for Courses on
  Westnetserver1, we would see the contents of this
  portion of the file server as shown on the NT
  Server for Courses Diagram.

Summary
Quiz
Terms
NT Server for Courses
32
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• Print Servers
• Special servers or basic workstations can be used
  as print servers.
  
• Each type may require third-party software.
• All software-based servers require central
  processing unit (CPU) cycles from a workstation
  or the file server.
  
• If the station is turned off, print services
  disappear until the machine is turned on again.

Summary
Quiz
Terms
33
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• Print Servers (cont.)

Summary
Quiz
Terms
Print Server
34
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• Communication Servers
• Separate communication servers may also be
  desirable.
  
• This type of server allows pooling of resources
  such as modems and phone lines rather than
  printers.
  
• They are also called remote access servers
  (RASs), or servers with RAS capabilities.
  

Summary
Quiz
Terms
35
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• Communication Servers (cont.)

Summary
Quiz
Terms
Remote Access Server
36
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• Communication Servers (cont.)
• Communication usually needs multipleserial
  ports.
  
• Communication ports have high interrupt rates,
  which degrade file server performance.
  
• Buffering and management of the communication
  link is necessary.

Summary
Quiz
Terms
37
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• Communication Servers (cont.)
• Communications is inherently less reliable than
  printer sharing.
  
• Some LAN administrators prefer to isolate this
  possible problem component onto a separate
  server.
  
• Security is usually enhanced in communication
  servers.
  

Summary
Quiz
Terms
38
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• Web Servers
• Web servers are used in a variety of ways in
  computer networks.
  
• Intranets are Web servers used internally by an
  organization.
  
• Extranets are Web servers used internally with
  limited outside access.

Summary
Quiz
Terms
Key Point

• Intranets and Extranetsare types of web servers.

39
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• Web Servers (cont.)
• Other Web servers are accessed by anyone attached
  to the Web.
  
• The Web is based on the concept of hypertext and
  hypermedia.
  
• Hypertext is text that can be linked with
  selected phrases.
  
• Hypertext contains connections within the text to
  other documents.

Summary
Quiz
Terms
40
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• Web Servers (cont.)
• Hypermedia is another form of hypertext that
  include images, sounds, and video with links that
  can be selected and viewed.
  
• The Web allows an easy interchange of hypermedia
  between networked environments.
  
• Some of these clients may be terminal browsers,
  PCs running Windows, Macintosh computers, or X
  Windows on UNIX workstations.

Summary
Quiz
Terms
41
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• Web Servers (cont.)
• A Web server is a computer program whose only
  purpose is to serve documents to other computers.
  
  
• Web client software (usually a browser) is a
  program that interfaces with a user and requests
  documents from a server.
  

Summary
Quiz
Terms
42
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• Servers and Web Page Requests
• When a client computer requests a Web page
  located on the same network (Intranet), the
  server responds with the information requested
  (Web page).
• The server knows to respond with the Web page
  based on the IP address and port number of the
  client request.
  

Summary
Quiz
Terms
43
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• Servers and Web Page Requests (cont.)

Summary
Quiz
Terms
Web Page Response
44
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Servers and Network Operating Systems (cont.)
Lesson 5

• Servers and Web Page Requests (cont.)
• The Web page is returned to the client that made
  the request.
  
• The Web page is contained within the message,
  packet, and frame.
  
• File servers contain application software and
  data files that are downloaded to workstations on
  request.
  
• Consolidating power, memory, and disk space in
  the server reduces workstation hardware
  requirements.

Summary
Quiz
Terms
45
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Activities
Lesson 5

• A small group of users running a popular desktop
  operating system have outgrown their peer-to-peer
  network and wish to upgrade to a client/server
  environment.
• In addition to transferring the company files
  over to a server, the users also require access
  to two laser printers, a high-end plotting
  device, and the Internet.
• Some of the users have requested that remote
  access from their home PCs be available on the
  new system.

Summary
Quiz
Terms
46
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Activities (cont.)
Lesson 5

• The printers and plotter all have a built-in
  TCP/IP stack and Ethernet NIC.
  
• They run a handful of standard applications, such
  as word processing, spreadsheets, and e-mail, as
  well as two custom applications for the plotting
  device.
• 1) Draw a network diagram illustrating the new
  client/server system, making sure all user
  requirements are fully met. Assume five users
  currently, with growth to four more users in the
  next six months.

Summary
Quiz
Terms
47
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4
Activities (cont.)
Lesson 5

• 2) Label all the components, both hardware and
  software. Include the server operating system as
  well as the clients' operating system. Be sure to
  label the Internet access device as well. Note
  any additional software installed at the server
  and clients, such as networking software. Be
  thorough. You may choose to connect the clients
  to the server with either a hub or switch.

Summary
Quiz
Terms
48
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4

• 1) If a server is available, log on to a
  client/server network.
  
• 2) Enter a user name and password to access the
  server. Can a single user name and password be
  used for everyone?
  
• 3) Compare functions that a peer-to-peer network
  supports versus functions that a client/server
  supports. What are some functions/support that
  are only available in a client/server
  environment? Discuss.

Extended Activities
Lesson 5
Summary
Quiz
Terms
49
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Network Servers
and Services
Lesson 2
Lesson 3
Lesson 4

• 4) Go to Web sites such as www.shiva.com and
  www.microsoft.com, and find information on
  virtual private networks (VPNs). What are VPNs
  used for? Discuss some applications.

Extended Activities (cont.)
Lesson 5
Summary
Quiz
Terms
50
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4

• As networks grow and users and services are added
  to a network, performance problems may arise.
  
• There are a number of ways to isolate traffic to
  segments of a network to increase the performance
  of the overall network.

Lesson 5
Summary
Quiz
Terms
51
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4

• At the end of this lesson you should
• Understand why traffic must be managed
• Understand devices commonly used to manage
  traffic in a network

Objectives
Lesson 5
Summary
Quiz
Terms
Key Point

• Isolating traffic increasesoverall network
  bandwidth.

52
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4
Traffic Management

• Most small networks are created using simple
  hubs.
  
• As more users are added to a network, the amount
  of information, or traffic, increases.
  
• As networks grow and traffic increases, it is
  often necessary to divide a network into physical
  segments to manage traffic more effectively.

Lesson 5
Summary
Quiz
Terms
53
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4
Traffic Management (cont.)

• In many networks, multiple servers are needed to
  perform the required functions of various groups
  or departments.

Lesson 5
Summary
Quiz
Terms
Multiple Servers
54
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4
Traffic Management (cont.)

• When information is sent from one client to any
  server in the network, the frame and frame
  contents travel to each node in the network.
  
• Frames are "broadcast" to all computers including
  the servers, using the entire bandwidth of the
  network during transmission.

Lesson 5
Summary
Quiz
Terms
55
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4
Traffic Isolation

• Network Component devices were developed to help
  manage traffic by isolating information into
  different segments of a network.
  
• As performance becomes an issue, networked
  computers are physically separated with devices
  such as switches and routers to increase the
  overall network bandwidth and performance.

Lesson 5
Summary
Quiz
Terms
56
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4
Traffic Isolation (cont.)

• The network becomes more efficient by
• Dividing computers and servers into logical
  workgroups
  
• Isolating the workgroups with such devices
• Internetworking devices are used to segment a
  network and distribute traffic between logical
  and physical network segments.

Lesson 5
Summary
Quiz
Terms
57
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4
Traffic Isolation (cont.)
Lesson 5
Summary
Quiz
Terms
Switched Backbone
58
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4
Traffic Isolation (cont.)

• Information sent by a client computer destined
  for a server in the same workgroup will be
  isolated to that segment of the network.
  
• The information will not cross theswitch
  boundary.
  
• Information headed for the Intranet server will
  not be transmitted to the other workgroup.
  

Lesson 5
Summary
Quiz
Terms
59
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4
Traffic Isolation (cont.)

• Information headed for the print server, and
  ultimately a printer in the network, will not be
  transmitted to another workgroup.
  
• A router may also be used in this configuration.
  
  
• Like a switch, a router will isolate traffic in
  individual workgroups when information is being
  sent between members of the same workgroup.

Lesson 5
Summary
Quiz
Terms
60
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4
Traffic Isolation (cont.)

• Information destined for the Intranet server or
  print server will not be visible in the other
  workgroup.
  
• Isolation is only one of the issues that comes
  into play when segmenting a network.
  
• Connecting to other networks is another important
  consideration.

Lesson 5
Summary
Quiz
Terms
61
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4
Consider the following diagram depicting a netwo
rk
Activities
Lesson 5
Summary
Quiz
Terms
62
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4
Activities (cont.)
Lesson 5
1) What portion of the header will switch use to
move information to an Intranet Server?
2) What portion of the header will the router use
to move information through the network?
3) What device(s) form the backbone of this
network?
Summary
Quiz
Terms
63
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4
Consider the following network
Activities (cont.)
Lesson 5
Summary
Quiz
Terms
64
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4
Activities (cont.)
Lesson 5

• 4) Is the switch performing port switching or
  segment switching?
  
• 5) Trace the path from one of the clients on the
  left to the Web Servers. Does traffic from this
  client reach the right-most hub?
  

Summary
Quiz
Terms
65
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4
Extended Activities
Lesson 5

• Perform the following exercise that demonstrates
  the differences between using hubs and switches.
  This exercise is intended for a Windows 95
  peer-to-peer environment with sharing enabled on
  all clients.
• 1) Configure a network in a peer-to-peer, Windows
  95 network using a hub.

Summary
Quiz
Terms
66
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4
Extended Activities (cont.)
Lesson 5
2) Transfer a large file (25 MB) from one clien
t to another client without going through a
central hub (disconnect workgroup hub from
central hub if attached). Record the time it
takes to transfer the file. 3) Transfer a large f
ile to and from each client (or multiple clients)
connected via a hub. Record the time it takes to
transfer the file. Because multiple files are
transferred simultaneously, average the time.
Summary
Quiz
Terms
67
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Traffic
Isolation in a Network
Lesson 2
Lesson 3
Lesson 4
Extended Activities (cont.)
Lesson 5
4) Tie all Workgroups hubs together into a centr
al hub and transfer the same number of files
between clients as in Step 3 of this exercise. In
the WestNet lab you will have to tie the hub to
the wall, which then goes to the patch panel.
From the patch panel, tie into the hub. Record
the time it takes to transfer the files. Discuss
results. 5) Replace the central hub with a switch
and repeat Step 4. Record the time it takes to
transfer the files. Discuss results.
Summary
Quiz
Terms
68
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Connectivity to
Other Networks
Lesson 2
Lesson 3
Lesson 4
Networks are connected to other networks in a
variety of ways, of which routers are the most
common.
Lesson 5
Summary
Quiz
Terms

• At the end of this lesson you should be able to
• Understand how routers isolate traffic in a
  network
  
• Understand why routers are used to connect LANs
  to other LANs
  

Objectives
Key Point

• Routers have more capabilitiesthan hubs and
  switches.

69
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Connectivity to
Other Networks
Lesson 2
Lesson 3
Lesson 4

• Switches provide a backbone for a network and
  switched frames between different workgroups in
  the network.
  
• The frame address is used by the switch to make
  the switching decision.
  
• A network in which a router is used to isolate
  traffic looks very similar to the switched
  backbone network.

Routers and Traffic Isolation
Lesson 5
Summary
Quiz
Terms
70
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Connectivity to
Other Networks
Lesson 2
Lesson 3
Lesson 4

• One of the primary differences is that routers
  can be used to connect to other networks.

Routers and Traffic Isolation (cont.)
Lesson 5
Summary
Quiz
Terms
Router Backbone
71
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Connectivity to
Other Networks
Lesson 2
Lesson 3
Lesson 4

• Another difference between switches and routers
  is the method used to isolate traffic to
  individual segments of a network.
  
• Switches isolate traffic by looking at the frame
  address and forwarding the frame out the correct
  switch port.
  
• Routers remove the packet from the frame to make
  a routing decision.

Routers and Traffic Isolation (cont.)
Lesson 5
Summary
Quiz
Terms
72
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Connectivity to
Other Networks
Lesson 2
Lesson 3
Lesson 4

• If the packet is destined for another segment of
  the network, a new frame is built and forwarded
  out the correct router port.
  
• There are advantages and disadvantages to each
  approach
  
• Performance gains packets are not analyzed and
  new frames do not have to be built.
  
• Routers, however, provide more functionality.

Routers and Traffic Isolation (cont.)
Lesson 5
Summary
Quiz
Terms
73
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Connectivity to
Other Networks
Lesson 2
Lesson 3
Lesson 4

• When connecting LANs to other LANs, routers are
  used.
  
• A router can serve as a backbone in a network.
• It can provide connectivity to outside networks.
• A router can be used in conjunction with
  switches, where the switch is used locally and
  the router provides outside connectivity when
  needed.

LAN to LAN Connectivity
Lesson 5
Summary
Quiz
Terms
74
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Connectivity to
Other Networks
Lesson 2
Lesson 3
Lesson 4

• Here, a router is used as the backbonein the
  network and also for access to other networks.

LAN to LAN Connectivity (cont.)
Lesson 5
Summary
Quiz
Terms
LAN to LAN Communication
75
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Connectivity to
Other Networks
Lesson 2
Lesson 3
Lesson 4

• The router is used by clients in one network to
  access files on a remote file server in another
  network.
  
• It receives a frame from one of the clients.
• The packet is analyzed by the router to see where
  the packet is destined in the network.
  
• The destination address of the packet indicates
  the node where the packet is headed.

LAN to LAN Connectivity (cont.)
Lesson 5
Summary
Quiz
Terms
76
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Connectivity to
Other Networks
Lesson 2
Lesson 3
Lesson 4

• The frame destination address is the router's
  NIC, the packet address is the remote file
  server.
  
• Packets destined for nodes within the first
  network do not cross the router boundary.
  

LAN to LAN Connectivity (cont.)
Lesson 5
Summary
Quiz
Terms
77
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Connectivity to
Other Networks
Lesson 2
Lesson 3
Lesson 4
Activities
1) A router is a cost-effective solution to traf
fic isolation. True or False 2) A switch looks at
the network address to decide where to forward
the data. True or False 3) Routers are normally
used to interconnect remote LANs. True or False
Lesson 5
Summary
Quiz
Terms
78
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Connectivity to
Other Networks
Lesson 2
Lesson 3
Lesson 4
Activities (cont.)
4) A router that connects two local LAN segments
(subnets) to a remote LAN has a total of three
interface cards. True or False
5) Where possible, it is more efficient to route
traffic than switch traffic. True or False
Lesson 5
Summary
Quiz
Terms
79
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Connectivity to
Other Networks
Lesson 2
Lesson 3
Lesson 4
Extended Activities

• Routers can be used to erect a "firewall" between
  parts of a network. The protocol used for routing
  by the Network Layers of the various
  communication architectures does not involve
  sending broadcast packets. By using routers,
  broadcast messages are kept behind a "firewall."
  When addressing and other problems occur, they
  are experienced by only a small group of users
  and are much easier to localize and resolve.

Lesson 5
Summary
Quiz
Terms
80
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Connectivity to
Other Networks
Lesson 2
Lesson 3
Lesson 4
Extended Activities (cont.)
1) Why is it important to localize this type of
traffic? Can a bridge also be used to isolate
broadcast messages? Discuss. 2) Discuss the vario
us common services that can be used to
interconnect routers across WANs. What is
considered "low-end" service? What is considered
"high-end" service? 3) Use a Web search engine an
d find information on "backbone routers." Compare
various product offerings.
Lesson 5
Summary
Quiz
Terms
81
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
We will look at common application-to-application
traffic found in computer networks.
Lesson 5
Summary
Quiz
Terms

• At the end of this lesson you should
• Understand how information flows in a typical
  network
  
• Understand the format of information as it flows
  across a network
  

Objectives
Key Point

• Routers are used to provideconnectivity to the
  Internet.

82
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
Common Network Configuration

• Many networks use a combination of hubs,
  switches, and routers to move information from
  source to destination.
  
• The following network includes hubs attached to
  switches.
  
• The switches connect the users attached to the
  hubs, and provide connectivity to common servers
  and other networks.

Lesson 5
Summary
Quiz
Terms
83
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
Common Network Configuration (cont.)
Lesson 5
Summary
Quiz
Terms
Common Network Configuration
84
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
Information Flow on a Local Segment
Lesson 5

• Information travelling from one client attached
  to a hub, to another client attached to the same
  hub, will not pass the switch.
  
• All clients attached to that hub will receive the
  frame
  
• Only the client whose NIC has an address that
  matches the destination address of the frame will
  process the information inside the frame.

Summary
Quiz
Terms
85
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
Information Flow on a Local Segment (cont.)
Lesson 5

• After the frame is processed by the NIC, the
  packet layer destination address is examined to
  see if it matches the node's Network Layer
  address.
• The Transport Layer determines the application
  the message is intended for, and passes the
  message to it.

Summary
Quiz
Terms
86
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
Information Flow on a Local Segment (cont.)
Lesson 5

• During transmission of this frame, no other
  clients attached to the hub can send information
  because they are all on the same physical
  segment.
• Other clients on the network can send
  information, because the switch does not allow
  the frame to travel to other parts of the
  network.

Summary
Quiz
Terms
87
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
Information Flow Across a Switched Backbone
Lesson 5

• The flow of information from a client to an
  Intranet server
  

Summary
Quiz
Terms
Client to Intranet Server
88
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
Information Flow Across a Switched Backbone
(cont.)
Lesson 5

• The client sends information to the Intranet
  server via the hub and switch.
  
• The switch looks at the destination address of
  the frame and forwards the frame out the correct
  port to the Intranet server.
  
• After the frame is processed by the NIC in the
  server, the packet layer destination address is
  examined by the Layer 3 process in the server to
  see if the address matches the node's Network
  Layer address.

Summary
Quiz
Terms
89
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
Information Flow Across a Switched Backbone
(cont.)
Lesson 5

• The addresses match and the packets are passed up
  to the Transport Layer.
  
• The Transport Layer determines the application
  that the message is intended for, and passes the
  message to the correct application, the Intranet
  server software.
• The only difference is the application
• A browser such as Netscape is used on the client.
  
  
• On the server, a Web server software package is
  used.
  

Summary
Quiz
Terms
90
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4

• Flow of information from a client in one network
  to a Web server in another network.

Information Flow Across a Wide Area Network
Lesson 5
Summary
Quiz
Terms
Web Server Request
91
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
Information Flow Across a Wide Area Network
(cont.)
Lesson 5

• When a client in a network needs to send
  information to a server in another network, it
  must address the frame to the router in the
  network.
• In this network, the client sends the information
  first to the hub which sends the frame to the
  switch.
  
• The switch, based on the destination address of
  the frame, forwards the frame to the router.

Summary
Quiz
Terms
92
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
Information Flow Across a Wide Area Network
(cont.)
Lesson 5

• The destination address of the frame matches the
  NIC in the router.
  
• The router NIC sends the packet (IP packet) to
  the IP process of the router.
  
• The destination IP address does not match the
  Network Layer address of the router, so the
  router does its job and routes the packet toward
  the final destination.

Summary
Quiz
Terms
93
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
Information Flow Across a Wide Area Network
(cont.)
Lesson 5

• The router sends the packet across the wide area
  network (WAN) link by placing the packet in a new
  frame.
  
• The packet is put into a WAN frame, determined by
  the type of WAN link the packet is travelling
  across.
  
• The router at the other end evaluates the packet
  address and, because there is no match, forwards
  the packet to the Web server.

Summary
Quiz
Terms
94
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
Information Flow Across a Wide Area Network
(cont.)
Lesson 5

• This time the packet is put inside a new frame,
  similar to the frame sent by the first client.
  
• The Web server responds to the client by sending
  a packet back to the client containing Web page
  information.
  

Summary
Quiz
Terms
Key Point

• IP Packet addresses identifythe destination
  computer.

95
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
Consider the following network
Activities
Lesson 5
Summary
Quiz
Terms
96
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
1) Fill in the protocol stacks on the server and
client, as well as the Ethernet frame with the
appropriate information to complete the diagram.
2) Describe the flow of a request between the Web
browser and Web server. 3) What kind of UTP cabl
ing would be most likely used in the LAN?
Activities (cont.)
Lesson 5
Summary
Quiz
Terms
97
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
4) Could this LAN be operated at a speed of 100
Mbps, if it were running at 10 Mbps, by just
replacing the NICs? 5) The frame shown traveling
between the routers has a WAN header. What
happened to the Ethernet header?
6) Describe the flow of information from Client
A, across the WAN, to the Web server at the right
of the network diagram. 7) What type of WAN proto
cols could be used between the routers?
Activities (cont.)
Lesson 5
Summary
Quiz
Terms
98
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
Extended Activities
Divide into focus groups. Discuss the following
1) The differences between hubs, switches, and
routers in light of the network configurations
shown in this lesson. 2) Where network bottleneck
s are likely to occur, and what might be done
about alleviating potential network congestion
(consider the server load).
Lesson 5
Summary
Quiz
Terms
99
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Information
Flow from Client to Web Server
Lesson 2
Lesson 3
Lesson 4
Extended Activities (cont.)
Divide into focus groups. Discuss the following
3) Compare the Internet, intranets, and extrane
ts. 4) List five applications that Web technologi
es address. 5) Where will the state of networking
be three to five years from now.
Lesson 5
Summary
Quiz
Terms
100
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Summary
Lesson 2
Lesson 3
Lesson 4

• Many similarities exist between the clients in a
  peer-to-peer network and information flow between
  a client and server.
  
• In a peer-to-peer network either device is
  capable and just as likely to initiate
  communication as any other.
  
• In a client/server environment, the client
  typically initiates a request to a server, and
  the server responds (replies) to the client with
  the requested information.

Lesson 5
Summary
Quiz
Terms
101
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Summary
Lesson 2
Lesson 3
Lesson 4

• Peer-to-peer networks become client/server
  networks by adding appropriate hardware and
  software to a computer.
  
• NOSs are added to computer hardware to create
  servers.
  
• Both peer-to-peer traffic and client/server
  traffic can exist in the same network.
  
• As networks grow, traffic increases and at some
  point may create performance problems in the
  network.

Lesson 5
Summary
Quiz
Terms
102
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Summary
Lesson 2
Lesson 3
Lesson 4

• Devices such as switches and routers are used to
  isolate traffic to logical groupings of network
  devices.
  
• The choice of whether to switch or route is
  dependent on the functionality required by the
  network.
  
• A switch is used for performance boosts and is
  more efficient than a router.
  
• A router is used to provide connectivity to other
  networks and for specialized functionality such
  as security (e.g., firewalls).

Lesson 5
Summary
Quiz
Terms
103
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Summary
Lesson 2
Lesson 3
Lesson 4

• Frames are built to cross links, carrying packets
  from source to destination.
  
• Applications communicate through software ports,
  including client application port to network
  application port.

Lesson 5
Summary
Quiz
Terms
104
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Quiz
Lesson 2
Lesson 3
Lesson 4
1) List the four major components necessary to
build a small peer-to-peer network.
Lesson 5
Summary
Quiz
Terms
105
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Terms
Lesson 2
Lesson 3
Lesson 4
Access DeviceAn access device is a network
component used to gain access to network
resources from a remote location, and vice versa.
Common access devices are routers and modem
pools. Modem pools are banks of modems that allow
multiusers to dial in to an organizations local
area network (LAN).
Lesson 5
Summary
Quiz
Terms
106
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Terms
Lesson 2
Lesson 3
Lesson 4
BackboneThe backbone of a network is the portion
that carries the most significant traffic. It is
also the part of the network that connects many
LANs or subnetworks together to form a network.
Bridges are often used to form network backbones.
In this configuration, bridges often limit local
traffic from the backbone to reduce congestion
and isolate problems.
Lesson 5
Summary
Quiz
Terms
107
Introduction to Networking
Introduction
Lesson 1
Integrating the Course Elements Terms
Lesson 2
Lesson 3
Lesson 4
FirewallAccording to the National Computer
Security Association, a firewall is a system or
combination of systems that enforces a boundary
between two or more networks. It is a controlled
gateway between one network and another,
typically between a private network and the
Internet.
Lesson 5
Summary
Quiz
Terms