EE 486 Data Communication Networks

Electrical Engineering Department

Faculty of Engineering Alexandria University

Spring 2017

Bassem Mokhtar, Ph.D. Assistant Professor

Department of Electrical Engineering

Faculty of Engineering

Alexandria University

Introduction 1-1

Agenda

Course Overview

Introduction to Data Communication and

Networks

Introduction to the Internet

Network Models (

Introduction to the Network Layer

Network layer functions

Introduction 1-2

Course Information

Instructor: Dr. Bassem Mokhtar

Teaching Assistants: Eng. Nour Nabil and Eng. Kareem Attiah

Lecture hours: 3 One lecture weekly (Saturdays) 11:50 am to 1:20 pm

One lecture bi-weekly (Saturdays) 1:40 pm to 3:10 am

Location: m2

Tutorial and lab hours: 2 One tutorial class bi-weekly

One lab class bi-weekly

Office hours Thursdays from 12:30 pm to !:00 pm

Course website: http://eng.staff.alexu.edu.eg/~bmokhtar/ Introduction 1-3

Course Objectives

Having successfully completed this course, the

student will be able to comprehensively understand

Four major concepts: data and computer communications,

networking, protocols and standards, and networking

models, network security

The data communication components in data networks,

how different types of data can be represented, and how

to create a reliable secure data flow through various

network topologies and contexts Introduction 1-4

References

Lecture Notes

Text Books

B. Forouzan, Data Communications and Networking. 5th ed., New

York: McGraw-Hill, 2013

W. Stallings, Data and Computer Communications. 10th ed. Upper

Saddle River, New Jersey: Prentice Hall, 2013.

James Kurose and Keith Ross, Computer Networking: A Top Down

Approach, the 6th edition,, Addison-Wesley, 2013

Reading Materials

Introduction 1-5

Assessment

Midterm Exam: 20% (25 marks)

Labs and Assignments: 12% (15 marks)

Project: 8% (10 marks) with bonus

Submitting project paper related to topic/application

that employs or depends on basic network concepts

• Grading will relay on project materials understanding, quality

of submitted paper, presentation and oral discussion

Final Exam: 60% (75 marks)

Introduction 1-6

Course Outline Introduction to Data Communications, Data Networking, and the Internet

Physical Layer and Media

Data Link Layer: Error Detection and Correction, Data Link Control, Multiple

Access, Fast Ethernet, WLANs

Network Layer: Logical Addressing, Internet Protocol, Address Mapping, unicast

and multicast routing (3 lectures)

Transport Layer: Process-to-Process Delivery, Congestion Control (2 lectures)

Application Layer: Domain Name System, Electronic Mail, and File Transfer,

SNMP, Multimedia (3 lectures)

Security: symmetric and asymmetric key cryptography, CIA (2 lectures)

Introduction 1-7

Project The final project will run in parallel with the course. Each

team (up to six students per team) will choose freely topic/application that depends on basic network concepts

The application will be chosen by the team on a first-come first-serve (FCFS) basis (no more than one team per application)

The team will need to do more extensive searching for the latest research work concerning the selected application

Each team will prepare and submit a project paper (using WORD or LATEX) which provides qualitative and quantitative study for their application

Each team must work on a different application

Teams will Submit a progress report by the mid of the semester

Submit final report, present their project and they will be discussed Introduction 1-8

Project Topics (Example) - big data analysis in IoT - data routing in wireless sensor networks - network function virtualization - software defined networking-based network management - data forwarding challenges in opportunistic networks - artificial intelligence in future computer networks - semantics driven networking operation - video streaming in mobile wireless networks - mobile ad hoc networks - mobile cloud computing infrastructure - virtual machines in network hosts - virtual machine migrations in cloud computing environments - self-aware computer networks - intelligent sensor networks - wireless sensor networks for object localization

Introduction 1-9

Project Groups Formation and Progress Report

Project groups formation Due date: 9/3/2017

Class representative should send me the formed groups (names and their selected topics)

Project progress report (3 marks) Due date: 15/4/2017

Each group will submit a short progress report including: topic abstract, their work plan and expected outcomes and deliverables, current status and achieved tasks, and next tasks

Introduction 1-10

Data Communications and Networks

Data Communications

deals with the transmission of signals in a reliable and

effective manner. Topics covered include signal

transmission, transmission media, signal encoding,

interfacing, data link control, and multiplexing.

Networking

deals with the technology and architecture of the

communication networks used to interconnect

communicating devices (entities). Topics include network

topologies and networking protocols Introduction 1-11

Data Communications and Networks

Data Communications between two devices

Networks provide networking services between two entities

The communications between two end-points uses Protocol

Introduction 1-12

A Communications Model Source

Generates (binary) data to be transmitted

Transmitter Converts data into transmittable

electromagnetic signals

Transmission system This can be a single transmission line or a

complex network

Receiver Converts received signal into data

Destination Takes incoming data

Introduction 1-13

Simplified Communications Model Diagram

Introduction 1-14

Communications Tasks

Introduction 1-15

The Transmission of Information

The basic building block of any communications

facility is the transmission line (medium)

Providing the required capacity, with acceptable

reliability, at minimum cost

For long-distance communications: fiber optic

transmission and wireless transmission (e.g., satellite

and radio)

To increase the efficiency of data transmission,

multiplexing and compression approaches are used Introduction 1-16

Data Communication Networking

Point to point communication not usually

practical

Devices are too far apart

Large set of devices would need impractical

number of connections

Solution is a communications network

Wide Area Network (WAN)

Local Area Network (LAN) Introduction 1-17

Circuit Switching

Dedicated communications path established

for the duration of the conversation

Data transmission is rapid, without delay

This kind of switching is good for real-time

services

The typical network which adopts this kind of

switching is telephone network

Introduction 1-18

Packet Switching

Data sent out of sequence Small chunks (packets) of data at a time Packets passed from node to node between

source and destination At each node, the entire packet is received,

stored briefly, and then transmitted to the next node

Used for terminal to computer and computer to computer communications

There are two kinds of packet switching: Virtual circuit and datagram

Introduction 1-19

The Internet Definition: network of interconnected networks

History The Internet evolved from the ARPANET in 1969 in

four locations

ARPA applied the same packet-switching technology to tactical radio communication and to satellite communication

ARPA developed methods and protocols for internetworking (Transmission Control Protocol “TCP” in 1974)

Now, The number of connections to the Internet continues to grow exponentially (billions users, hosts, devices IoT)

Introduction 1-20

The Internet Key elements that comprise the Internet

Network Models 1-21

Key Elements of the Internet

The purpose of the Internet, of course, is to interconnect end systems, called hosts (PCs, workstations, servers, mainframes)

Hosts are connected to a network (LAN, WAN)

Networks are connected by routers

Each router attaches to two or more networks

Some hosts, such as mainframes or servers, connect directly to a router rather than through a network

Protocols to enable communication and data transfer between different Internet elements

Introduction 1-22

Protocols In computer networks, communication occurs

between entities in different systems

For communication to occur, the entities must agree on a protocol

A protocol a set of rules that governs data communications

defines what is communicated, how it is communicated, and when it is communicated.

The key elements of a protocol Syntax

Semantics

Timing Introduction 1-23

Network Criteria

A network must be able to meet a certain number of criteria Performance (response time, throughput, delay,

etc.)

Reliability (accuracy of data delivery, frequency of failure, etc.)

Security (Confidentiality, Integrity, Availability) • protecting data from unauthorized access

• Protecting data from damage

• implementing policies and procedures for recovery from breaches and data losses

Introduction 1-24

Network Performance Latency (Delay)

defines how long it takes for an entire message to

completely arrive at the destination from the time the

first bit is sent out from the source

𝐿𝑎𝑡𝑒𝑛𝑐𝑦

= 𝑝𝑟𝑜𝑝𝑎𝑔𝑎𝑡𝑖𝑜𝑛 𝑡𝑖𝑚𝑒 + 𝑡𝑟𝑎𝑛𝑠𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝑡𝑖𝑚𝑒

+ 𝑞𝑢𝑒𝑢𝑖𝑛𝑔 𝑡𝑖𝑚𝑒 + 𝑝𝑟𝑜𝑐𝑒𝑠𝑠𝑖𝑛𝑔 𝑑𝑒𝑙𝑎𝑦

• Propagation time measures the time required for a bit to travel

from the source to the destination

𝑝𝑟𝑜𝑝𝑎𝑔𝑎𝑡𝑖𝑜𝑛 𝑡𝑖𝑚𝑒 =𝑡𝑟𝑎𝑣𝑒𝑙𝑖𝑛𝑔 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒

𝑝𝑟𝑜𝑝𝑎𝑔𝑎𝑡𝑖𝑜𝑛 𝑠𝑝𝑒𝑒𝑑 Introduction 1-25

Network Performance Latency (Delay)

• Transmission time measures the time required for transmission of

a message depending on the size of the message and the

bandwidth of the channel

𝑝𝑟𝑜𝑝𝑎𝑔𝑎𝑡𝑖𝑜𝑛 𝑡𝑖𝑚𝑒 =𝑚𝑒𝑠𝑠𝑎𝑔𝑒 𝑠𝑖𝑧𝑒

𝑐ℎ𝑎𝑛𝑛𝑒𝑙 𝑏𝑎𝑛𝑑𝑤𝑖𝑑𝑡ℎ

• Queuing time measures the time needed for each intermediate

(router) or end device to hold the message before it can be

processed

– The queuing time is not a fixed factor; it changes with the load

imposed on the network

– When there is heavy traffic on the network, the queuing time

increases Introduction 1-26

An Abstract Look to the Traditional Internet Operation

Based on the concept: intelligent end systems and dummy core and offer best effort QoS

Operation example A host may send data to another host anywhere on the

Internet

The source host breaks the data to be sent into a sequence of packets (IP or Internet Protocol packets)

Each packet includes a unique numeric address of the destination host (IP address)

Based on this destination address, each packet travels through a series of routers and networks from source to destination

Introduction 1-27

Simplified View of Portion of Internet

Network Models 1-28

Hierarchical Organization of the Internet

Introduction 1-29

Internet Service Provider (ISP): A company that provides other companies or individuals with access to, or presence on, the Internet

Network Models A network is a combination of hardware and

software sending data from one location to another The hardware consists of the physical equipment that

carries signals

The software consists of instruction sets that make the required services possible

The fundamental job of executing a service with a computer is done by computer hardware

At the highest level, a software can direct the execution process such as the details of how this is done by the actual hardware

Network Models 1-30

Network Models Illustrative Example

Sending an e-mail from one point in the world to another

The main tasks are broken into many tasks performed by a separate software package

Each software package uses the services of another software package through the defined protocols

• Employing suitable protocol (SMTP)

• Establishing end-to-end connection (TCP)

• Adding final destination address (IP)

• Encrypting data, adding physical address, accessing medium of next hop destination (MAC)

At the lowest layer, a signal, or a set of signals, is sent from the source computer to the destination computer (physical layer) Network Models 1-31

Layered Tasks

Network Models 1-32

The OSI Layers

Network Models 1-33

The Interaction between Layers in the OSI Model

Network Models 1-34

TCP/IP Concepts

Network Models 1-35

A Comparison of the OSI and TCP/IP Protocol Architectures

Network Models 1-36

Addressing in TCP/IP Model Four levels of addresses are used in an internet

employing the TCP/IP protocols

Physical Addresses: the unique address of a node as defined by

its LAN or WAN. It is included in the frame used by the data link layer. For example, Ethernet uses a 6-byte (48-bit) physical address (MAC address)

Logical Addresses: necessary for universal communications that are independent of underlying physical networks. A logical address in the Interne is currently a IPv4 (32-bit) address or IPv6 (128 bits) address that can uniquely define a host connected to the Internet. Used by the network layer. Network Models 1-37

Addressing in TCP/IP Model

Port Addresses: • The IP address and the physical address are necessary

for a quantity of data to travel from a source to the destination host

• arrival at the destination host is not the final objective of data communications on the Internet

• computers are devices that can run multiple processes at the same time

• The end objective of Internet communication is a process communicating with another process

• There is a need to a method to label the different processes such as transferring files and sending emails

• A port address in TCP/IP is 16 bits in length.

• Used by the transport layer Network Models 1-38

Addressing in TCP/IP Model

Specific Addresses: • Some applications have user-friendly addresses that are

designed for that specific address

• Examples include the e-mail address and the Universal Resource Locator (URL)

• These addresses, however, get changed to the corresponding port and logical addresses by the sending computer

• Used by the application layer

Network Models 1-39

Addressing in TCP/IP Model The physical addresses change from hop to hop, but the

logical and port addresses usually remain the same

Network Models 1-40

Introduction to the Network Layer

Goals of studying the network layer understand principles behind network layer

services: network layer service models forwarding versus routing how a router works routing (path selection) dealing with scale advanced topics: IPv6, mobility

implementation in the Internet

Network Layer 1-41

1-42

Introduction to the Network Layer

transport segment from sending to receiving host

on sending side encapsulates segments into datagrams

on rcving side, delivers segments to transport layer

network layer protocols in every host, router

router examines header fields in all IP datagrams passing through it

application transport network data link physical

application transport network data link physical

network data link physical

network data link physical

network data link physical

network data link physical

network data link physical

network data link physical

network data link physical

network data link physical

network data link physical

network data link physical

network data link physical

Network Layer

Two Key Network-Layer Functions

Network Layer 1-43

forwarding: move packets from router’s input to appropriate router output

routing: determine route taken by packets from source to dest.

routing algorithms

analogy:

routing: process of planning trip from source to dest

forwarding: process of getting through single interchange

Introduction 1-44

Lecture Summary Covered material

Course Overview

Introduction to Data Communication and Networks

Introduction to the Internet

Network Models

Introduction to the Network Layer

Network layer functions

Material to be covered next lecture Continue: The network layer

Service models

Network layer connection and connectionless services

Data routing in datagram and virtual circuit networks