Network Services
Networking for Home and Small Businesses – Chapter 6
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Compare and Contrast Clients and Servers
 Server
– host running software application that provides information to
other hosts on network
– all servers use same types of protocols and standards
– Example: Web Server
 Client
– name given to an application that a host uses
– Example: Web browser
• host uses web client software to request a web page
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Types of Servers
 DNS (Domain Name Server/System)
– translates the IP address of web site from its domain name
 Telnet
– allows remote login/access to a device
 E-mail
– like its name implies they supply e-mail access
 DHCP-used to supply dynamic IP addresses, first used by network
clients before other servers.
 Web
– uses HTTP protocol
 FTP
– used to download and/or upload files between clients and servers
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Client-Server Protocols
 Application Layer Protocols
– determine the way in which a server and client interact
– HTTP – way to convey information on the web
– SMTP – used to transfer e-mail from server to server
–FTP – used to transfer files
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Activity #1
 Open the Cisco curriculum on your computer and
navigate to page 6.1.1.4 and complete the server
activity that asks you to match the server with the
request from the computer. Drag the server to the
requesting computer screen to see if you are correct.
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Server Cost
 Lets take a quick look at the cost of servers.
 Using www.tigerdirect.com lets compare the prices and
features of the following two servers. To complete your
comparison you may design a venn diagram or T-Chart
(either on paper or on the computer)
 Insert a definition of what a server is then compare 2.
 Servers to Compare 1) Lenovo ThinkServer TS140
Item # LQW-102028974 model # 70A4001RUS and 2)
Cybertron PC Magnum TSVMIB1281 Tower Server
Item # C122-08710 Model # TSVMIB1281and
compare the two servers based on the following
items.
 1) Price 2)Total Memory Size 3)Processor Speed
4)Processor Type/Class 5)Power 6) Warranty
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Graphic Design – 6 Server Layout
 Using a piece of printer paper create a graphic design
of the six main types of servers that are commonly
found within the networking world today. Besides
listing the names of the servers also include a
description of each server and include the above info
inside a picture of a server picture.
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TCP (Transmission Control Protocol)
 Used by FTP and HTTP to allow transmissions to occur
 Provides acknowledgment of delivery of the packet
– similar to registered mail
 How it works . . .
– Message into segments
– Segments are then numbered (1,2,3…..)
–Keeps track of the number of segments
– If sender does not receive the segments
– The lost portion is retransmitted
 Use of TCP will slow down delivery. Why??
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UDP Protocols
 U = UNRELIABLE
 “Best effort delivery”
 No acknowledgment, no guarantee
– similar to “snail mail”
 No retransmission
 Used by:
– streaming audio
– streaming video
– VoIP
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Activity
 Go to Cisco Page 6.1.3.4 and test your knowledge over
TCP and UDP protocols.
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Port Numbers in Client-Server Conversations
 Used by both TCP and UDP
 Keeps track of different conversations across the
network
 Every message includes a source and destination port
 Destination port
– sent by client in the segment to tell what service is requested
• Port 80 = HTTP
• Port 21 = FTP
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HTTP
 Used to display web pages
 HTML
– helps display the contents of a web page
 HTTP – unsecured protocol
– Port 80
 HTTPS – provides extra security/encryption
– Port 443
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Port Numbers Graphical Design
 Open the port numbers graphical design sheet on Mr.
Smith’s website and complete the graphical design of
the key port numbers that are requested.
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DNS Server (Domain Name System)
 Translates a domain name (URL) into an IP address
 Some groups
– .com
– .edu
 Port 53 = DNS
– used if clients wants an IP address of a web site or host
 To convert www.cisco.com to 198.133.219.25 one
would use what type of application?
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In The Lab Activity
 Select a person to work with. One person open the lab
found on page 6.2.1.3, the other person will open up
the CMD prompt and as a team complete the lab. Only
one answer sheet is needed and this can be typed or
hand written on a sheet of paper.
 You have 10 minutes to complete
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FTP (File Transfer Protocol)
 Host must run FTP client access to access the FTP
server
 Two ports used to communicate
– FTP Request = Port 21
– To transfer files when open = Port 20
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Email Protocols used by E-mail Severs
 SMTP (Simple Mail Transfer Protocol)
– used by email client to send messages to local email server
– allows e-mail servers to communicate with each other
– Port #25
 POP3 (Post Office Protocol)
– receives/stores messages for the users
– when client connects to email server messages are
downloaded to the client; messages are removed from server
– Port #110
 IMAP (Internet Message Across Protocol)
– receives/stores messages but keeps messages on the server
unless deleted by user
– Port #143
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VoIP (Voice Over IP)
 IP packets carry digitized voice as data
 How it works
– Download client software from company service provider
– Once software is installed, user selects a unique name
– Calls made by selecting a username from list
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IM
 What client software enables logged in users to
communicate with other logged in users in real time?
Instant Messaging
 What common program is used for Instant messaging?
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Port Numbers
 ICANN (Internet Corp for Assigned Names and
Numbers)
– assigns port numbers
 Messages received will have a destination port
number which will help the computer use the correct
application to open up data.
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 Copy the Port # list found on page 6.2.7.1 it will look
close to the chart shown on the next slide.
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Port Numbers
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Activity #2
 Navigate to page 6.2.7.2 and complete the Port
Number activity. Look at the destination port number
and select the appropriate protocol.
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The Protocol Stack
What term is used to describe how TCP/IP protocols are
layered and interact to format, address, and transmit
information across a network? Protocol Stack
 Upper Layers
– message content
 Lower Layers
– help to move data
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Encapsulation (sending data)
 From top to bottom
 Application data broken into segments
– segments contain source and destination ports
 TCP segments sends it down to Internet layer
– source and destination IP added (packet)
 Packet put into a frame
– header and trailer added
• header = source and destination MAC
• trailer = error checking
 Broken into bits
– encoded onto the media (cabling)
 What 3 things are found in the Ethernet Header and Trailer?
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Question
 A device receives an Ethernet frame and recognizes
the MAC address as its own. What does the device do
to the message to get to the encapsulated data?
 Removes the Ethernet header and trailer
 A client has decoded a frame and started the deencapsulation process. In which order does the deencapsulation process occur?
 1) remove Ethernet header and trailer
2) remove IP header
3) remove TCP header
4) pass data to the application
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De-encapsulation (receiving data)
 From bottom to top
 Bits are decoded from the media
 Frame removes header and trailer
 Packet removes the IP address
– source and destination IP
 Segment is received and reassembled for the user
– viewing a web page
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Why Use a Layered Model?
1)Allows competition between vendors
– can all work together
 2)One layer does not affect other layers
 3)Allows for a common language
 TCP/IP Model and its layers are below…
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OSI MODEL
 Developed in 1984
 Reference model for how computers interact with each
other
 Organized into more specific groups than the TCP/IP
Model
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OSI Layer Research Task
 We are going to break into seven groups (Size will be 3-4 members)
 Each group is to design a one-page sheet that illustrates the
assigned OSI layer using printer paper.

At the top of the paper should be the name of the layer,
somewhere else on the sheet should be a brief description about
what occurs at the layer which should include any devices and/or
protocols that are used. A picture should also be included to help
someone remember the overall purpose of the layer (the group
decides the picture but it must be relevant).
 We will post the seven layers in the room when each group is
finished.
 Use the Internet or the Cisco curriculum (Chapter 6) to assist your
group.
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OSI Model
 Layer 1 is mainly concerned with cables, wires and
electricity.
 Layer 7 is concerned with applications and programs.
 Easy Way to Remember The OSI Model
 All People Seem To Need Data Processing
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IP Header
 What is contained in the IP Header?
source and destination IP addresses
 Using google perform a search for IP Header which
should show the various components that make up the
header. Copy the image to your notes before you go
on to the next step below.
 Activity #3 – Go to page 6.3.3.4 within the Cisco
curriculum and drag the correct addresses, or port
numbers into the Ethernet frame, remember the IP
portion will be IP addresses, the TCP will be port
numbers and the Ethernet portions will be MAC
addresses.
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Packet Tracer Activity
 Open Packet tracer and then using File, Open select
the lab called Cisco I 6.3.3.5 over PDU information sent
between client and servers. PDU stands for Protocol
Data Unit.
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Quiz
 Take the Cisco chapter 6 quiz found on page 6.5.5.1 to
test your knowledge.
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