1. Local & Metropolitan Area Networks
ACOE322
Lecture 5
TCP/IP Protocol suite
and
IP addressing
Dr. L. Christofi

2. We shall cover in this topic:
0. INTRODUCTION
We shall cover in this topic:
The relation of TCP/IP with internet and OSI model
Internet layer
Transport layer and UDP
Application layer
Dr. L. Christofi

3. 1. History and Future of TCP/IP
The U.S. Department of Defense (DoD) created the TCP/IP reference model because it wanted a network that could survive any conditions.
Some of the layers in the TCP/IP model have the same name as layers in the OSI model.
Dr. L. Christofi

4. Application Layer
Handles high-level protocols, issues of representation, encoding, and dialog control.
The TCP/IP protocol suite combines all application related issues into one layer and ensures this data is properly packaged before passing it on to the next layer.
Dr. L. Christofi

5. Transport Layer Five basic services:
Segmenting upper-layer application data
Establishing end-to-end operations
Sending segments from one end host to another end host
Ensuring data reliability
Providing flow control
Dr. L. Christofi

6. Layer 4 Protocols
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7. Internet Layer
The purpose of the Internet layer is to send packets from a network node and have them arrive at the destination node independent of the path taken.
Internet layer protocols:
Internet Protocol (IP)
Internet Control Message Protocol (ICMP)
Address Resolution Protocol (ARP)
Reverse Address Resolution Protocol (RARP)
Dr. L. Christofi

8. Network Access Layer
The network access layer is concerned with all of the issues that an IP packet requires to actually make a physical link to the network media.
It includes the LAN and WAN technology details, and all the details contained in the OSI physical and data link layers.
Dr. L. Christofi

9. Comparing the OSI Model and TCP/IP Model
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10. Similarities of the OSI and TCP/IP models
Both have layers.
Both have application layers, though they include very different services.
Both have comparable transport and network layers.
Packet-switched, not circuit-switched, technology is assumed.
Networking professionals need to know both models.
Dr. L. Christofi

11. Differences of the OSI and TCP/IP models
TCP/IP combines the presentation and session layer into its application layer.
TCP/IP combines the OSI data link and physical layers into one layer.
TCP/IP appears simpler because it has fewer layers.
TCP/IP transport layer using UDP does not always guarantee reliable delivery of packets as the transport layer in the OSI model does.
Dr. L. Christofi

12. Internet Architecture
Two computers, anywhere in the world, following certain hardware, software, protocol specifications, can communicate, reliably even when not directly connected.
LANs are no longer scalable beyond a certain number of stations or geographic separation.
Dr. L. Christofi

13. 2. TCP/IP Internet layer
Internet Addresses
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14. IP Address as a 32-Bit Binary Number
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15. Binary and Decimal Conversion
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16. IP Address Classes
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17. IP Address Classes
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18. IP Addresses as Decimal Numbers
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19. Hosts for Classes of IP Addresses
Class A (24 bits for hosts) * = 16,777,214 maximum hosts
Class B (16 bits for hosts) * = 65,534 maximum hosts
Class C (8 bits for hosts) * = 254 maximum hosts
* Subtracting the network and broadcast reserved address
Dr. L. Christofi

20. IP Addresses as Decimal Numbers
Class D: Multicast
Class E: Research
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21. Network IDs and Broadcast Addresses
An IP address such as that has all binary 0s in the host bit positions is reserved for the network address.
An IP address such as that has all binary 1s in the host bit positions is reserved for the broadcast address.
Dr. L. Christofi

22. Private Addresses
These addresses are NEVER used on the Internet and should never appear on the Internet.
They are used only for private networks.
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23. Reserved Address Space
Network ID
Broadcast address
Hosts for classes of IP addresses
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24. Basics of Subnetting Classical IP addressing Subnetworks Subnet mask
Boolean operations: AND, OR, and NOT
Performing the AND function
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25. Subnetworks
To create a subnet address, a network administrator borrows bits from the original host portion and designates them as the subnet field.
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26. Subnetworks
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27. Subnet Mask
Determines which part of an IP address is the network field and which part is the host field
Follow these steps to determine the subnet mask:
1. Express the subnetwork IP address in binary form.
2. Replace the network and subnet portion of the address with all 1s.
3. Replace the host portion of the address with all 0s.
4. Convert the binary expression back to dotted-decimal notation.
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28. Subnet Mask
Subnet mask in decimal =
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29. Boolean Operations: AND, OR, and NOT
Recall
AND is like multiplication
OR is like addition
NOT changes 1 to 0, and 0 to 1.
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30. Performing the AND Function
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31. Range of Bits Needed to Create Subnets
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32. Subnet Addresses
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33. Decimal Equivalents of 8-Bit Patterns
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34. Creating a Subnet Determining subnet mask size
Computing subnet mask and IP address
Computing hosts per subnetwork
Boolean AND operation
IP configuration on a network diagram
Host and subnet schemes
Private addresses
Dr. L. Christofi

35. Determining Subnet Mask Size
Class B address with 8 bits borrowed for the subnet
(8 bits borrowed for subnetting) routes to subnet rather than just to network
Dr. L. Christofi

36. Determining Subnet Mask Size
Class C address with a subnet mask of (3 bits borrowed)
100
00011
Network Field SN
Host Field
The address would be on the subnet
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37. Subnetting Example with AND Operation
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38. IP Configuration on a Network Diagram
The router connects subnetworks and networks.
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39. Host Subnet Schemes
The number of lost IP addresses with a Class C network depends on the number of bits borrowed for subnetting.
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40. Broadcast addresses exercise
Fill-in the class, subnet and broadcast IP addresses in the following table
Address Subnet Mask Class Subnet Broadcast
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41. Broadcast addresses exercise answer
Fill-in the class, subnet and broadcast IP addresses in the following table
Address Subnet Mask Class Subnet Broadcast C A B B A
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42. Exercise 1 Given the IP address 192.168.100.86 find The default mask
The subnet mask, assuming 5 bits of subnetting
The subnet IP address
The broadcast address
The first and last valid host IP addresses
Dr. L. Christofi

43. Exercise 1 answer Given the IP address 192.168.100.86 find
The default mask:
It is a class C address, therefore Default mask is
The subnet mask, assuming 5 bits of subnetting
5 bits for subnet, 3 remaining bit for host addresses, so subnet mask is
The subnet IP address:
The broadcast address:
The first and last valid host IP addresses
1st valid host address:
Last valid host address:
Dr. L. Christofi

44. Exercise 2 Given the IP address 172.16.164.32/19 find The default mask
The subnet mask
The subnet IP address
The broadcast address
The first and last valid host IP addresses
Dr. L. Christofi

45. Exercise 2 answer Given the IP address 172.16.164.32/19 find
The default mask
It is a class B address, so Default mask is
The subnet mask:
The subnet IP address:
The broadcast address:
The first and last valid host IP addresses
1st valid host address:
Last valid host address:
Dr. L. Christofi

46. IPv4 versus IPv6
IP version 6 (IPv6) has been defined and developed.
IPv6 uses 128 bits rather than the 32 bits currently used in IPv4.
IPv6 uses hexadecimal numbers to represent the 128 bits.
IPv4
Dr. L. Christofi

47. Obtaining an IP Address
Static addressing
Each individual device must be configured with an IP address.
Dynamic addressing
Reverse Address Resolution Protocol (RARP)
Bootstrap Protocol (BOOTP)
Dynamic Host Configuration Protocol (DHCP)
DHCP initialization sequence
Function of the Address Resolution Protocol
ARP operation within a subnet
Dr. L. Christofi

48. Default Gateway A default gateway is the IP
address of the interface on the
router that connects to the
network segment on which the
source host is located.
Dr. L. Christofi

49. 3. TCP/IP Transport Layer
Five basic services:
Segmenting upper-layer application data
Establishing end-to-end operations
Sending segments from one end host to another end host
Ensuring data reliability
Providing flow control
Dr. L. Christofi

50. Flow Control
Avoids the problem of a host at one side of the connection overflowing the buffers in the host at the other side
Ensures the integrity of the data
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51. Session Establishment
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52. Three-Way Handshake
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53. Windowing
A method of controlling the amount of information transferred end to end
Information can be measured in terms of the number of packets or the number of bytes
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54. Window Size Larger window sizes increase communication efficiency.
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55. Acknowledgment
Positive acknowledgment requires a recipient to communicate with the source, sending back an acknowledgment message when it receives data.
Sender keeps a record of each data packet that it sends and expects an acknowledgment.
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56. Layer 4 Protocols
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57. TCP Connection oriented Reliable
Divides outgoing messages into segments
Reassembles messages at the destination station
Resends anything not received
Reassembles messages from incoming segments
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58. UDP Connectionless Unreliable
Transmits messages (called user datagrams)
Provides no software checking for message delivery (unreliable)
Does not reassemble incoming messages
Uses no acknowledgments
Provides no flow control
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59. TCP/IP Protocol Graph
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60. TCP Segment Format
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61. UDP Segment Format
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62. Port Numbers
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63. 4. TCP/IP Application Layer
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64. Responsibilities
Identifying and establishing the availability of intended communication partners
Synchronizing cooperating applications
Establishing agreement on procedures for error recovery
Controlling data integrity
Dr. L. Christofi

65. Application Layer Examples
Domain Name System (DNS)
File Transfer Protocol (FTP)
Hypertext Transfer Protocol (HTTP) and World Wide Web (WWW)
Simple Mail Transport Protocol (SNTP)
Simple Network Management Protocol (SNMP)
Telnet
Dr. L. Christofi

66. Domain Name System (DNS)
To identify an entity the Internet uses the IP address, which uniquely identifies the connection of a host to the Internet
However, people prefer to use names instead of numeric addresses
Therefore we need a system that can map a name to an address or an address to a name
When the Internet was small, mapping was done using a host file
Today is impossible to have a single host file to relate every address to a name and vice versa. The host file would be too large to store in every host
One solution is to store the entire host file in a single computer and allow access to this centralized info to every PC that needs a mapping – but this would create a huge amount of traffic
Another solution is to divide this huge amount of info into smaller parts and store each part on a different computer. In this method, the host that needs mapping can contact the closest computer holding the needed info.
This method is used by the DNS system.
Dr. L. Christofi

67. Domain Name System
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68. FTP (1)
File transfer protocol (FTP) is a TCP/IP client-server application for copying files from one host to another.
FTP requires two connections for data transfer: a control connection and a data connection.
FTP employs ASCII for communication between dissimilar systems.
Prior to the actual transfer of files, the file type, data structure, and transmission mode are defined by the client through the control connection.
Responses are sent from the server to the client during connection establishment.
Dr. L. Christofi

69. FTP (2) There are three types of file transfer:
  A file is copied from the server to the client.
  A file is copied from the client to the server.
  A list of directories or file names is sent from the server to the client.
Most operating systems provide a user-friendly interface between FTP and the user.
Anonymous FTP provides a method of the general public to access files on remote sites.
Dr. L. Christofi

70. SMTP
One of the most important network services is electronic mail ( )
Electronic mail is used for sending a single message that includes text, voice, video or graphics to one or more recipients
Simple Mail Transfer Protocol (SMTP) is the standard mechanism for electronic mail in the Internet
Dr. L. Christofi

71. SMTP
servers communicate with each other using the Simple Mail Transport Protocol (SMTP) to send and receive mail.
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72. SMTP
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73. HTTP
The Hypertext Transfer Protocol (HTTP) is used mainly to access data on the World Wide Web.
Hypertext Markup Language (HTML) is a language used to create static Web pages.
The protocol transfers data in the form of plain text, hypertext, audio, video and so on.
It is called HTTP because it is used in an environment where there are rapid jumps from one document to another
HTTP functions like a combination of FTP and SMTP
- It is similar to FTP because it transfers files and uses the services of TCP (via port 80). There is no separate control connection – only data are transferred between the client and the server
- HTTP is also similar to SMTP because the data transferred between the client and the server are similar to SMTP messages
Dr. L. Christofi

74. WWW (1)
The HTTP is the main protocol used to access data on the World Wide Web (WWW).
The World Wide Web is a repository of information spread all over the world and linked together.
Hypertext and hypermedia are documents linked to one another through the con-cept of pointers.
Browsers interpret and display a Web document.
A browser consists of a controller, client programs, and interpreters.
A Web document can be classified as static, dynamic, or active.
A static document is one in which the contents are fixed and stored in a server. The client can make no changes in the server document.
Any browser can read formatting instructions (tags) embedded in an HTML document.
Dr. L. Christofi

75. WWW (2)
A dynamic Web document is created by a server only at a browser request.
The Common Gateway Interface (CGI) is a standard for creating and handling dynamic Web documents. A CGI program with its embedded CGI interface tags can be written in a language such as C, C++, shell script, or Perl.
The server sends the output of the CGI program to the browser.
The output of a CGI program can be text, graphics, binary data, status codes, instructions, or an address of a file.
An active document is a copy of a program retrieved by the client and run at the client site.
Java is a combination of a high-level programming language, a run-time environment, and a class library that allows a programmer to write an active document and a browser to run it.
Java is used to created applets (small application programs).
Java is an object-oriented typed language with a rich library of classes.
Dr. L. Christofi

76. SNMP
The Simple Network Management Protocol (SNMP) is an application layer protocol that facilitates the exchange of management information between network devices.
An SNMP managed network consists of the following:
Network management system (NMS)
Managed device
Agents
Dr. L. Christofi

77. Telnet
Telnet client software provides the ability to log in to a remote Internet host that is running a Telnet server application and then to execute commands from the command line.
Dr. L. Christofi

78. Exercise 3
Design a private LAN, with the following topology, that would allow the exchange of data:
Your subnet is You should use appropriate subnet mask and assign appropriate IP addresses to all network elements (routers & hosts) having in mind possible future expansion of your network for 5 additional hosts. You have been told not to waste unnecessary IP addresses.
Dr. L. Christofi

79. Exercise 3 (answer) Subnet is 192.168.200.64.
Present number of hosts is 5, Number of routers is 2 and for future expansion 5 additional hosts, makes a total of 12 addresses.
Hence use Subnet Mask.
Broadcast IP address for this network is reserved to therefore available IP addresses are from to
Dr. L. Christofi

80. References
W. Stalling, Local and Metropolitan Area Networks, 6th edition, Prentice Hall, 2000
B.A. Forouzan, Data Communications and Networking, 3rd edition, McGraw-Hill, 2004
W. Stallings, Data and Computer Communications, th edition, Prentice Hall, 2004
F. Halsall, Data Communications, Computer Networks and Open Systems, 4th edition, Addison Wesley, 1995
Dr. L. Christofi