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