Prof. Hosny Ibrahim

 Text book (TX1): Data and Computer Communications By: William Stalling, 11 th Edition 2011  Text book (TX2): Data Communications and networking By: Behrouz A. Forouzan, 4 th Edition /28/2015 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 11/28/2015 Data Communication IT 221 By: Prof. Hosny M. Ibrahim 3

 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.,. 11/28/2015 Data Communication IT 221 By: Prof. Hosny M. Ibrahim 4

5-Data Link layer: Errors types, Error Detection Data link Control, HDLC protocol Flow control, stop and wait, sliding window, go back n 6- Multiplexing, FDM, TDM, ADSL lines, xDSL Circuit and packet switching,..X25, Frame Relay…, ATM. 7- Wired LANs, Ethernet I.EEE /28/2015 Data Communication IT 221 By: Prof. Hosny M. Ibrahim 5

1.6 DATA COMMUNICATIONS DATA COMMUNICATIONS The term telecommunication means communication at a distance. The word data refers to information presented in whatever form is agreed upon by the parties creating and using the data. Data communications are the exchange of data between two devices via some form of transmission medium such as a wire cable. 11/28/2015Data 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 11/28/2015 Data Communication IT 221 By: Prof. Hosny M. Ibrahim 7

11/28/2015 Data Communication IT 221 By: Prof. Hosny M. Ibrahim 8

1.9 Five components of data communication ( Network ) 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

1.10 Data flow (simplex, half-duplex, and full-duplex) 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

1.11 NETWORKS NETWORKS A network is a set of devices (often referred to as nodes) connected by communication links. A node can be a computer, printer, or any other device capable of sending and/or receiving data generated by other nodes on the network. 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

1.12 Types of connections: point-to-point and multipoint 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

1.13 Categories of topology 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

1.14 A fully connected mesh topology (five devices) 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

1.15 A star topology connecting four stations 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

1.16 A bus topology connecting three stations 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

1.17 A ring topology connecting six stations 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

1.18 A hybrid topology: a star backbone with three bus networks 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

1.19 An isolated LAN connecting 12 computers to a hub in a closet 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

1.20 WANs: a switched WAN and a point-to-point WAN 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

1.21 A heterogeneous network made of four WANs and two LANs 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

1.22 THE INTERNET THE INTERNET The Internet has revolutionized many aspects of our daily lives. It has affected the way we do business as well as the way we spend our leisure time. The Internet is a communication system that has brought a wealth of information to our fingertips and organized it for our use. 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

1.23 Hierarchical organization of the Internet 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

1.24 PROTOCOLS AND STANDARDS PROTOCOLS AND STANDARDS In this section, we define two widely used terms: protocols and standards. First, we define protocol, which is synonymous with rule. Then we discuss standards, which are agreed-upon rules. 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.25 LAYERED TASKS LAYERED TASKS We use the concept of layers in our daily life. As an example, let us consider two friends who communicate through postal mail. The process of sending a letter to a friend would be complex if there were no services available from the post office. 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.26 Tasks involved in sending a letter 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.27 THE OSI MODEL THE OSI MODEL Established in 1947, the International Standards Organization (ISO) is a multinational body dedicated to worldwide agreement on international standards. An ISO standard that covers all aspects of network communications is the Open Systems Interconnection (OSI) model. It was first introduced in the late 1970s. 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.28 ISO is the organization. OSI is the model. Note 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.29 Seven layers of the OSI model 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.30 The interaction between layers in the OSI model 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.31 An exchange using the OSI model 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.32 LAYERS IN THE OSI MODEL LAYERS IN THE OSI MODEL 1-Physical Layer 2-Data Link Layer 3-Network Layer 4-Transport Layer 5-Session Layer 6-Presentation Layer 7-Application Layer 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

Physical layer 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.34 The physical layer is responsible for movements of individual bits from one hop (node) to the next. Note 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

Data link layer 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.36 The data link layer is responsible for moving frames from one hop (node) to the next. Note 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.37 Hop-to-hop delivery 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

Network layer 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.39 The network layer is responsible for the delivery of individual packets from the source host to the destination host. Note 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.40 Source-to-destination delivery 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

ransport layer 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.42 The transport layer is responsible for the delivery of a message from one process to another. Note 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.43 Reliable process-to-process delivery of a message 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

Session layer 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.45 The session layer is responsible for dialog control and synchronization. Note 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

Presentation layer 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.47 The presentation layer is responsible for translation, compression, and encryption. Note 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

Application layer 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.49 The application layer is responsible for providing services to the user. Note 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.50 Summary of layers 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.51 TCP/IP PROTOCOL SUITE The layers in the TCP/IP protocol suite do not exactly match those in the OSI model. The original TCP/IP protocol suite was defined as having four layers: host-to-network, internet, transport, and application. However, when TCP/IP is compared to OSI, we can say that the TCP/IP protocol suite is made of five layers: physical, data link, network, transport, and application. Physical and Data Link Layers Network Layer Transport Layer Application Layer Topics discussed in this section: 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.52 TCP/IP and OSI model 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.53 ADDRESSING Four levels of addresses are used in an internet employing the TCP/IP protocols: physical, logical, port, and specific. Physical Addresses Logical Addresses Port Addresses Specific Addresses 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.54 Addresses in TCP/IP 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.55 Relationship of layers and addresses in TCP/IP 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

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 /28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.57 Physical addresses 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

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 :01:02:01:2C:4B A 6-byte (12 hexadecimal digits) physical address. 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

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 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.60 IP addresses 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

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 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.62 Port addresses 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.63 The physical addresses will change from hop to hop, but the logical addresses usually remain the same. Note 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

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. 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

2.65 The physical addresses change from hop to hop, but the logical and port addresses usually remain the same. Note 11/28/2015Data Communication IT 221 By: Prof. Hosny M. Ibrahim

 Thank You Data Communication IT 221 By: Prof. Hosny M. Ibrahim 66 11/28/2015