Prof. Hosny Ibrahim. Text book (TX1): Data and Computer Communications By: William Stalling, 11 th Edition 2011 Text book (TX2): Data Communications

Prof. Hosny Ibrahim

Text book (TX1): Data and Computer Communications By: William Stalling , 11th Edition 2011

Text book (TX2): Data Communications and networking By: Behrouz A. Forouzan , 4th Edition 2007

04/18/23 Data Communication IT 221 By: Prof. Hosny M. Ibrahim 2

Course Scores 30 points semester work ( 20 mid term , 10 quizzes and

class work) 70 points Final exam


1-Overview of data communications, components of comm. networking Model OSI, TCP/IP , LAN, WAN

2- Physical Layer: Data transmission, analog, digital data, Spectrum, BW, Channel capacity ……

3-Channel Impairments, Noise.. transmission Media, guided, Wireless

4-LOS transmission, Signal Encoding; DD-AS, DD-DS, AD-AS, AD-DS, … DD

communication Techniques, Asyn, Sync Trans.,.


5-Data Link layer: Errors types, Error Detection Data link Control, HDLC protocol Flow control, stop and wait, sliding window, go back n6- Multiplexing, FDM, TDM, ADSL lines, xDSL Circuit and packet switching , ..X25, Frame Relay… , ATM.7- Wired LANs , Ethernet I.EEE802.11


1.6

DATA COMMUNICATIONSDATA COMMUNICATIONS

The term The term telecommunicationtelecommunication means communication at a means communication at a distance. The word distance. The word datadata refers to information presented in refers to information presented in whatever form is agreed upon by the parties creating and whatever form is agreed upon by the parties creating and using the data. using the data. Data communicationsData communications are the exchange of are the exchange of data between two devices via some form of transmission data between two devices via some form of transmission medium such as a wire cable. medium such as a wire cable.

04/18/23 Data Communication IT 221 By: Prof. Hosny M. Ibrahim

Source generates data to be transmitted

Transmitter Converts data into transmittable signals

Transmission System Carries data

Receiver Converts received signal into data

Destination Takes incoming data



1.9

Five components of data communication ( Network )


1.10

Data flow (simplex, half-duplex, and full-duplex)


1.11

NETWORKSNETWORKS

A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) ) connected by communication connected by communication linkslinks. A node can be a . A node can be a computer, printer, or any other device capable of sending computer, printer, or any other device capable of sending and/or receiving data generated by other nodes on the and/or receiving data generated by other nodes on the network.network.


1.12

Types of connections: point-to-point and multipoint


1.13

Categories of topology


1.14

A fully connected mesh topology (five devices)


1.15

A star topology connecting four stations


1.16

A bus topology connecting three stations


1.17

A ring topology connecting six stations


1.18

A hybrid topology: a star backbone with three bus networks


1.19

An isolated LAN connecting 12 computers to a hub in a closet


1.20

WANs: a switched WAN and a point-to-point WAN


1.21

A heterogeneous network made of four WANs and two LANs


1.22

THE INTERNETTHE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives. It has affected the way we do business as well as the lives. It has affected the way we do business as well as the way we spend our leisure time. The Internet is a way we spend our leisure time. The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use. information to our fingertips and organized it for our use.


1.23

Hierarchical organization of the Internet


1.24

PROTOCOLS AND STANDARDSPROTOCOLS AND STANDARDS

In this section, we define two widely used terms: In this section, we define two widely used terms: protocolsprotocols and and standardsstandards. First, we define protocol, which is . First, we define protocol, which is synonymous with rule. Then we discuss standards, which synonymous with rule. Then we discuss standards, which are agreed-upon rules.are agreed-upon rules.


2.25

LAYERED TASKSLAYERED TASKS

We use the concept of We use the concept of layerslayers in our daily life. As an in our daily life. As an example, let us consider two friends who example, let us consider two friends who communicate through postal mail. The process of communicate through postal mail. The process of sending a letter to a friend would be complex if there sending a letter to a friend would be complex if there were no services available from the post office. were no services available from the post office.


2.26

Tasks involved in sending a letter


2.27

THE OSI MODELTHE OSI MODEL

Established in 1947, the International Standards Established in 1947, the International Standards Organization (Organization (ISOISO) is a multinational body dedicated ) is a multinational body dedicated to worldwide agreement on international standards. to worldwide agreement on international standards. An ISO standard that covers all aspects of network An ISO standard that covers all aspects of network communications is the Open Systems communications is the Open Systems Interconnection (Interconnection (OSIOSI) model. It was first introduced in ) model. It was first introduced in the late 1970s. the late 1970s.


2.28

ISO is the organization.OSI is the model.

Note


2.29

Seven layers of the OSI model


2.30

The interaction between layers in the OSI model


2.31

An exchange using the OSI model


2.32

LAYERS IN THE OSI MODELLAYERS IN THE OSI MODEL

1-Physical Layer2-Data Link Layer3-Network Layer4-Transport Layer5-Session Layer6-Presentation Layer7-Application Layer


2.33

1- Physical layer


2.34

The physical layer is responsible for movements ofindividual bits from one hop (node) to the next.

Note


2.35

2-Data link layer


2.36

The data link layer is responsible for moving frames from one hop (node) to the next.

Note


2.37

Hop-to-hop delivery


2.38

3-Network layer


2.39

The network layer is responsible for the delivery of individual packets from

the source host to the destination host.

Note


2.40

Source-to-destination delivery


2.41

4-ransport layer


2.42

The transport layer is responsible for the delivery of a message from one process to another.

Note


2.43

Reliable process-to-process delivery of a message


2.44

5-Session layer


2.45

The session layer is responsible for dialog control and synchronization.

Note


2.46

6-Presentation layer


2.47

The presentation layer is responsible for translation, compression, and encryption.

Note


2.48

7-Application layer


2.49

The application layer is responsible for providing services to the user.

Note


2.50

Summary of layers


2.51

TCP/IP PROTOCOL SUITETCP/IP PROTOCOL SUITE

The layers in the The layers in the TCP/IP protocol suiteTCP/IP protocol suite do not exactly do not exactly match those in the OSI model. The original TCP/IP match those in the OSI model. The original TCP/IP protocol suite was defined as having four layers: protocol suite was defined as having four layers: host-to-network, internet, transport, and application. host-to-network, internet, transport, and application. However, when TCP/IP is compared to OSI, we can However, when TCP/IP is compared to OSI, we can say that the TCP/IP protocol suite is made of five say that the TCP/IP protocol suite is made of five layers: physical, data link, network, transport, and layers: physical, data link, network, transport, and application.application.

Physical and Data Link LayersNetwork LayerTransport LayerApplication Layer

Topics discussed in this section:Topics discussed in this section:


2.52

TCP/IP and OSI model


2.53

ADDRESSINGADDRESSING

Four levels of addresses are used in an internet Four levels of addresses are used in an internet employing the TCP/IP protocols: employing the TCP/IP protocols: physicalphysical, , logicallogical, , portport, , and and specificspecific..

Physical AddressesLogical AddressesPort AddressesSpecific Addresses


2.54

Addresses in TCP/IP


2.55

Relationship of layers and addresses in TCP/IP


2.56

In Figure 1 a node with physical address 10 sends a frame to a node with physical address 87. The two nodes are connected by a link (bus topology LAN). As the figure shows, the computer with physical address 10 is the sender, and the computer with physical address 87 is the receiver.

Example 2.1


2.57

Physical addresses


2.58

As we will see , most local-area networks use a 48-bit (6-byte) physical address written as 12 hexadecimal digits; every byte (2 hexadecimal digits) is separated by a colon, as shown below:

Example 2.2

07:01:02:01:2C:4B

A 6-byte (12 hexadecimal digits) physical address.


2.59

Figure 2 shows a part of an internet with two routers connecting three LANs. Each device (computer or router) has a pair of addresses (logical and physical) for each connection. In this case, each computer is connected to only one link and therefore has only one pair of addresses. Each router, however, is connected to three networks (only two are shown in the figure). So each router has three pairs of addresses, one for each connection.

Example 3


2.60

IP addresses


2.61

Figure 3 shows two computers communicating via the Internet. The sending computer is running three processes at this time with port addresses a, b, and c. The receiving computer is running two processes at this time with port addresses j and k. Process a in the sending computer needs to communicate with process j in the receiving computer. Note that although physical addresses change from hop to hop, logical and port addresses remain the same from the source to destination.

Example 4


2.62

Port addresses


2.63

The physical addresses will change from hop to hop,but the logical addresses usually remain the same.

Note


2.64

Example 5

A port address is a 16-bit address represented by one decimal number as shown.

753

A 16-bit port address represented as one single number.


2.65

The physical addresses change from hop to hop,but the logical and port addresses usually remain the

same.

Note


Thank You

Data Communication IT 221 By: Prof. Hosny M. Ibrahim 6604/18/23

Documents

Prof. Hosny Ibrahim. Text book (TX1): Data and Computer Communications By: William Stalling, 11 th Edition 2011 Text book (TX2): Data Communications