The document outlines the course structure for ECE 512L Data Communication, detailing key modules including fundamentals of data communications, data link control protocols, and networking concepts. It also covers the history of data communication, the architecture of communication networks, and the importance of data communication standards set by various organizations. The course aims to provide a comprehensive understanding of data communication protocols, network devices, and the evolution of technology in this field.

1. ECE 512L
Data Communication
Engr. Adriano Mercedes H. Cano Jr.
Electronics Engineering
College of Engineering Education
University of Mindanao - Tagum College

2. Course Outline
• Module 1: Data Communications
Fundamentals
– Communication model,
– Data communication network
– Standards,
– Protocol
– OSI model,
– TCP/IP,

3. Course Outline
• Module 2: Fundamental Concepts of Data
Communications
– Data Communications Circuits
– Data Communications Codes
– Bar Codes
– Line Control Unit
– Error Control
– Error Detection
– Error Correction
– Serial Interfaces
– Data Communications Modems
– ITU-T Modem Recommendations
– Character Synchronization

4. Course Outline
• Module 3: Data Link Control Protocols
– Data-Link Protocol Functions
– Character- and Bit-Oriented Data-Link
– Protocols
– Asynchronous Data-Link Protocols
– Asynchronous Transfer Mode
– Synchronous Data-Link Protocols
– High-Level Data-Link Control
– Public Switched Data Networks
– CCITT X.25 User-to-Network Interface Protocol
– Integrated Services Digital Network
– Synchronous Data-Link Control

5. Course Outline
• Module 4: Data Communication Networking
– Introduction to Switched Circuits
– Circuit Switching and Packet Switching
– Local Area Networks, Applications, and Architectures
• Ethernet
• Ring
• Token Ring
• FDDI
– Local Area Networks and Interconnections
• Repeaters
• Bridges and Switches
• Routers and Gateways
– The Internet
• Overview of the Internet
• The Internet Protocol
• Domain Name Systems
• Internet Protocol Over Internet

6. Reference Books
• Advance Electronics Communication
– Wayne Tomasi
• Data Communications and Networking
– Behrouz A. Forouzan

7. Module 1:
Data Communications Fundamentals

8. Introduction
• Data generally are defined as information
that has been processed, organized, and is
stored in digital form
• Information is defined as knowledge or
intelligence.
• Data communications is the process of
transferring digital information (usually in
binary form) between two or more points.

9. Data Communication
Standards
Error detection and correction
Network Devices
Header & Trailer
Encryption
Location A Location B

10. Introduction
• Data Transmission
• is the transmission, reception, and
processing of digital information
• Transmission is either parallel or serial

11. Introduction
• Transmission Modes
– Simplex (SX) mode, data transmission is unidirectional; receive-only,
transmit-only, or one-way-only lines.
• Ex. Commercial radio broadcasting
– Half-duplex (HDX) mode, data transmission is possible in both
directions but not at the same time. Also called two-way-alternate or
either-way lines.
• Ex. Citizens band (CB) radio
– Full duplex (FDX) mode, transmissions are possible in both directions
simultaneously, but they must be between the same two stations. also
called two-way simultaneous, duplex, or both-way lines.
• Ex. A local telephone
– Full/full duplex (F/FDX) mode, transmission is possible in both
directions at the same time but not between the same two stations (i.e.,
one station is transmitting to a second station and receiving from a third
station at the same time).
• Full/full duplex is possible only on multipoint circuits.
• Ex. postal system

13. • Data can be propagated to the network by
either
– Segment
– packet
– frame,
Introduction

14. • Data communications networks
– are systems of interrelated computers and
computer equipment(called nodes) and
connected together through the public
telephone network.(media links)
– Its purpose is to transfer digital information
from one place to another.
Introduction

16. History of Data Communication
• 1753. One of the earliest means of
communicating electrically coded information
through a 26 wire system.
• 1833. Carl Friedrich Gauss developed a system
based on a 5x5 matrix representing 25 letters.
• 1832. The telegraph (the first data
communication system) was invented by Samuel
F.B. Morse.
• 1840. The American patent for the telegraph was
granted.
• 1844. The first telegraph line was established
between Baltimore and Washington D.C.
conveying the first telegraph message “What
hath God wrought!”
16

17. • 1849. The first slow-speed telegraph printer was
invented.
• 1850. Western Union Telegraph Company was
formed in Rochester, New York, for the purpose
of carrying coded messages from person to
another.
• 1860. “High-speed” printers (15 bps) became
available.
• 1874. Emile Baudot invented the a telegraph
multiplexer that allowed signals from up to six
different telegraph machines to be transmitted
simultaneously over a single wire.
• 1875. The telephone was invented by Alexander
Graham Bell.
17
History of Data Communication

18. History of Data Communication
• 1899. Guglielmo Marconi succeeded in sending
radio (wireless) telegraph messages.
• 1920. The first commercial radio stations carrying
voice information were installed.
• 1930s. Konrad Zuis, a German engineer,
demonstated a computing machine.
• 1940. Bell Laboratories developed the first
special purpose computer using
electromechanical relays for performing logical
operations.
• 1946. The first modern-day computer (ENIAC)
was developed by J. Presper Eckert and John
Mauchley at the University of Pennsylvania.
18

19. History of Data Communication
• 1949. The U.S. National Bureau of Standards
developed the first all-electronic diode based
computed capable of executing stored-programs.
• 1950s. “Batch processing” computers used
punched cards as an input interface, printers as
an output interface, and magnetic tape reels for
data storage.
The first general purpose computer in
the form of an automatic sequence-controlled
calculator was developed jointly by Harvard
University and IBM Corporation.
• 1951. Remington Rand Corporation built the first
mass-produced electronic computer (UNIVAC).
19

20. History of Data Communication
• 1960s. Batch-processing systems were
replaced by on-line processing systems with
terminals connected directly to the
computer through serial or parallel
communication lines.
• 1968. The landmark US Supreme Court
Carterfone decision allowed non-Bell (non
AT&T) equipment to be connected to the
vast AT&T network.
• 1969. The internet began to evolve at the
Advanced Research Projects Agency (ARPA)
through the ARPANET.
• 1970s. Microprocessor-controlled
microcomputers were developed.
20

21. History of Datacom
• 1980s. Personal computers became an
essential item in the home and the
workplace. Since then, the need to
exchange digital information, and
consequently, the need for data
communication circuits, networks, and
systems increased exponentially.
• 1983. AT&T agreed in a court settlement to
divest itself of operating companies that
provide basic local telephone service to
various geographic regions of the US as a
result of an anti-trust suit filed by the federal
government.
21

22. History of Data Communication
• Mid 1980s to 1995. The United Stated National Science
Foundation (NSF) funded a high-speed backbone called
the NSFNET.
• 1989. Tim Berners-Lee and Robert Cailliau build the
prototype system which became the World Wide Web at
CERN.
• 1991. Anders Olsson transmits solitary waves through
an optical fiber with a data rate of 32 billion bits per
second.
• 1992. Neil Papworth sends the first SMS
Internet2 organization is created.
• 1994. Internet radio broadcasting is born.
22

23. History of Data Communication
• 1999. 45% of Australians have a mobile phone.
Sirius satellite radio is introduced.
• 2001. First digital cinema transmission by satellite
in Europe of a feature film by Bernard Pauchon
and Philippe Binant is undertaken.
• 2003. Apple launches the iTunes Music Store and
sells one million songs in its first week.
MySpace is launched.
• 2004. What would become the largest social
networking site in the world, Facebook is
launched.
• 2005. YouTube, the video sharing site is launched.
.
23

24. History of Data Communication
• 2006. Twitter, microblogging is
introduced.
24

25. Network Architecture
Network Architecture
Design of
communication
network
is a set of layers
and protocols
outline the
products and
services
is a framework for
the specification

26. • General classifications:
– Current: include the most modern and
sophisticated networks and protocols
available.
– Legacy: no one really wants to use it, but for
some reason it just will not go away.
– Legendary: Old and No longer in use
Network Architecture

27. • can be classified in two different ways:
– Broadcast :
• messages are intended for all subscribers on the
network
• all stations and devices on the network share a single
communication channel
– Point to point:
• All transmissions from one station are intended for and
received by the other station.
– multicasting:
• when messages are intended for a specific group of
subscribers.
Network Architecture

29. Network Architecture
electrical specifications
hardware arrangements
software procedures
Transmission media
layers of functional responsibility
Company A A Company YA
Company BA
Company X A
Protocol

30. Network Protocols
sets of rules that allows two
hardware or software
processes to work together
how much data can be sent?
how it will be sent? how much data can be sent?
how it will be addressed?
what procedure will be used to
ensure that there are no undetected errors?

31. Network Protocols
• Protocol stack
– The list of protocols used by a system, which
generally includes only one protocol per layer

32. Layered Network
Architecture
Consist of two or
more independent
levels.
Each level has a
specific set of
responsibilities and
functions
data transfer,
flow control,
data segmentation
reassembly,
sequence control,
error detection and
correction,
notification
Reduce Complexity
Standardizes interfaces
Facilitates modular
engineering
Ensure Interoperable
engineering
Accelerates evolution
simplifies teaching and
learning

33. Connection- oriented protocol
1. Establishes handshake before any
data are actually transmitted between
two stations.
2. Require s acknowledgement of the
data as they are being transmitted.
(ensure reliability)
3. Provide some means of error control
4. When a connection is no longer
needed, a specific handshake drops the
connection.
Network Protocols
Connections are sometimes referred to
as sessions, virtual circuits, or logical
connections.
Connectionless protocol
1. Send data with a source and
destination address without a
handshake .
2. Do not support error control or
acknowledgment procedures,
making them
3. Data being transmitted usually do
not have extra overhead

34. Network Protocols
Connection-oriented protocol
Connectionless protocol

35. Network Protocols
reliability

36. • Syntax
– refers to the structure or format of the data within
the message, which includes the sequence in
which the data are sent.
• Ex: the first byte of a message might be the address of
the source and the second byte the address of the
destination.
• Semantics
– refers to the meaning of each section of data.
• Ex: does a destination address identify only the
location of the final destination, or does it also identify
the route the data takes between the sending and
receiving locations?
Network Protocols

37. Copyright 2005 John Wiley & Sons, Inc 1 - 37
Data Comm. Standards
• Standard
– is an object or procedure considered by an authority
or by general consent as a basis of comparison
• Data communications standards are not laws,
however—they are simply suggested ways of
implementing procedures and accomplishing
results
• Guidelines that have been generally accepted by
the data communications industry

38. Copyright 2005 John Wiley & Sons, Inc 1 - 38
Data Comm. Standards
• Importance
– Compatibility of hardware and/or software systems among
different companies
– Help promote competition and decrease the price
• Types of Standards
– Formal standards
• Developed by an industry or government standards-making
body
– De-facto standards
• Emerge in the marketplace and widely used
• Lack official backing by a standards-making body

39. Copyright 2005 John Wiley & Sons, Inc 1 - 39
Standardization Processes
• Specification
– Developing the nomenclature and identifying
the problems to be addressed
• Identification of choices
– Identifying solutions to the problems and
choose the “optimum” solution
• Acceptance
– Defining the solution, getting it recognized by
industry so that a uniform solution is accepted

40. Copyright 2005 John Wiley & Sons, Inc 1 - 40
Some Data Comm. Standards
Layer Common Standards
5. Application layer
HTTP, HTML (Web)
MPEG, H.323 (audio/video)
IMAP, POP (e-mail)
4. Transport layer
TCP (Internet)
SPX (Novell LANs)
3. Network layer IP (Internet)
IPX (Novell LANs)
2. Data link layer
Ethernet (LAN)
Frame Relay (WAN)
PPP (dial-up via modem for MAN)
1. Physical layer
RS-232c cable (LAN)
Category 5 twisted pair (LAN)
V.92 (56 kbps modem)

41. Copyright 2005 John Wiley & Sons, Inc 1 - 41
Major Standards Bodies
• ISO (International Organization for Standardization)
– Technical recommendations for data communication interfaces
– Composed of each country’s national standards orgs.
– Based in Geneva, Switzerland (www.iso.ch)
• ITU-T (International Telecommunications Union –
Telecom Group
– Technical recommendations about telephone, telegraph and
data communications interfaces
– Composed of representatives from each country in UN
– Based in Geneva, Switzerland (www.itu.int)

42. Copyright 2005 John Wiley & Sons, Inc 1 - 42
• ANSI (American National Standards Institute)
– Coordinating organization for US (not a standards- making
body)
– www.ansi.org
• IEEE (Institute of Electrical and Electronic Engineers)
– Professional society; also develops mostly LAN standards
– standards.ieee.org
• IETF (Internet Engineering Task Force)
– Develops Internet standards
– No official membership (anyone welcomes)
– www.ietf.org
Major Standards Bodies

44. Standards
• Proprietary
– are generally manufactured and controlled by one
company.
– Ex: Apple Macintosh.
– Advantages
• are tighter control, easier consensus, and a monopoly.
– Disadvantages
• include lack of choice for the customers, higher
financial investment, overpricing, and reduced customer
protection against the manufacturer going out of
business.

45. Standards
• Open System
– any company can produce compatible equipment or
software; however, often a royalty must be paid to the
original company.
– Ex: IBM’s personal computer.
– Advantages
• customer have a choice, compatibility between venders, and
competition by smaller companies.
– Disadvantages
• less product control and increased difficulty acquiring
agreement
• between vendors for changes or updates.
• In addition, standard items are not always as
• compatible as we would like them to be.

46. STANDARDS ORGANIZATIONS
• A consortium of organizations, governments,
manufacturers, and users meet on a regular basis to
ensure an orderly flow of information within data
communications networks and systems by establishing
guidelines and standards.
• The intent is that all data communications equipment
manufacturers and users comply with these standards.
• Standards organizations generate, control, and
administer standards.
• Often, competing companies will form a joint
committee to create a compromised standard that is
acceptable to everyone.

47. • Each layer adds value to services provided by sets of
lower layers.
• The highest level is offered the full set of services
needed to run a distributed data application.
• Each layer is essentially independent of every other
layer.
• Advantages
– facilitates peer-to-peer communications protocols
• where a given layer in one system can logically communicate
with its corresponding layer in another system.
• allows different computers to communicate at different levels.
• Disadvantage
– tremendous amount of overhead required
Layered network architecture

48. In case of more >1 destination: service access point (SAP) address is
used to define which entity the service is intended.

49. Protocol Data Unit
• communications between two corresponding
layers requires PDU.
• can be a header added at the beginning of a
message or a trailer appended to the end of
a message.
• As data passes from one layer into another,
headers and trailers are added and removed
from the PDU.
• The process of adding or removing PDU
information is called encapsulation
/decapsulation

50. Protocol Data Unit

52. OPEN SYSTEMS INTERCONNECTION
• In 1983, the ISO and ITU-T (CCITT)
adopted a seven-layer communications
architecture reference model.
• The primary purpose is to serve as a
structural guideline for exchanging
information between computers,
workstations, and networks.
• Each layer consists of specific protocols for
communicating.

53. OPEN SYSTEMS INTERCONNECTION
• was developed to facilitate the
intercommunications of data processing
equipment by separating network
responsibilities into seven distinct layers.
• As with any layered architecture, overhead
information is added to a PDU in the form of
headers and trailers.
• In fact, if all seven levels of the OSI model are
addressed, as little as 15% of the transmitted
message is actually source information, and
the rest is overhead.

54. Open Systems Interconnection
54

55. Please Do Not Touch Steve’s Pet Alligator

56. Open Systems Interconnection
 User networking applications and
interfacing to the network
 Encoding language used in transmission
 Job management tracking
 Data tracking as it moves through a
network
 Network addressing and packet
transmission on the network
 Frame formatting for transmitting data
across a physical communications link
 Transmission method used to propagate
bits through a network
56
LAYERS FUNCTIONS

57. Open Systems Interconnection
57
TCP/IP

58. OSI and its Protocol Data Units
ECE @Saint Louis University, Baguio City 58

59. Physical layer

60. Data Link layer

61. Network layer

62. Transport layer

63. Session layer

64. Presentation layer

65. • Layered network
• architectures consist of two or more
independent levels
Application layer

66. DoD: Department of Defense

70. TCP/IP
• Transmission Control Protocol/Internet
protocol
• TCP at the transport layer and IP at the
network layer
• Designed by Vinton G. Cerf and Robert E.
Kahn
• developed by the United States Defense
Advanced Research Projects
Agency (DARPAor ARPA)

71. TCP
• Reliable, full-duplex, connection-oriented,
stream delivery
– Interface presented to the application doesn’t
require data in individual packets
– Data is guaranteed to arrive, and in the
correct order without duplications
• Or the connection will be dropped
– Imposes significant overheads

72. Applications of TCP
• Most things!
– HTTP, FTP, …
• Saves the application a lot of work, so
used unless there’s a good reason not to

73. TCP implementation
• Connections are established using a
three-way handshake
• Data is divided up into packets by the
operating system
• Packets are numbered, and received
packets are acknowledged
• Connections are explicitly closed
– (or may abnormally terminate)

74. TCP Packets
• Source + destination ports
• Sequence number (used to order packets)
• Acknowledgement number (used to verify
packets are received)

75. TCP Segment
Destination Port
Acknowledgment Number
Options... Padding
Data...
0 4 10 16 19 24 31
Source Port
WindowLen
Sequence Number
Reserved Flags
Urgent PointerChecksum
Field Purpose
Source Port Identifies originating application
Destination Port Identifies destination application
Sequence Number Sequence number of first octet in the segment
Acknowledgment # Sequence number of the next expected octet (if ACK flag set)
Len Length of TCP header in 4 octet units
Flags TCP flags: SYN, FIN, RST, PSH, ACK, URG
Window Number of octets from ACK that sender will accept
Checksum Checksum of IP pseudo-header + TCP header + data
Urgent Pointer Pointer to end of “urgent data”
Options Special TCP options such as MSS and Window Scale
You just need to know port numbers, seq and ack are added

76. TCP : Data transfer
HostClient
Send Packet 1
Start Timer
Retransmit Packet1
Start Timer
Packet should arrive
ACK should be sent
ACK would normally
Arrive at this time
Receive Packet 1
Send AXK 1
Time Expires
Receive ACK 1
Cancel Timer
Packet Lost
Timer
Timer

77. IP
• IP : Internet Protocol
– UDP : User Datagram Protocol
• RTP, traceroute
– TCP : Transmission Control Protocol
• HTTP, FTP, ssh

78. OSI Model TCP/IP Hierarchy Protocols
7th
Application Layer
6th
Presentation Layer
5th
Session Layer
4th
Transport Layer
3rd
Network Layer
2nd
Link Layer
1st
Physical Layer
Application Layer
Transport Layer
Network Layer
Link Layer
Link Layer : includes device driver and network interface card
Network Layer : handles the movement of packets, i.e. Routing
Transport Layer : provides a reliable flow of data between two hosts
Application Layer : handles the details of the particular application

79. IP
• Responsible for end to end transmission
• Sends data in individual packets
• Maximum size of packet is determined
by the networks
– Fragmented if too large
• Unreliable
– Packets might be lost, corrupted,
duplicated, delivered out of order

80. IP addresses
• 4 bytes
– e.g. 163.1.125.98
– Each device normally gets one (or more)
– In theory there are about 4 billion available
• But…

81. Routing
• How does a device know where to send
a packet?
– All devices need to know what IP
addresses are on directly attached
networks
– If the destination is on a local network,
send it directly there

82. Routing (cont)
• If the destination address isn’t local
– Most non-router devices just send
everything to a single local router
– Routers need to know which network
corresponds to each possible IP address

83. Allocation of addresses
• Controlled centrally by ICANN
– Fairly strict rules on further delegation to
avoid wastage
• Have to demonstrate actual need for them
• Organizations that got in early have
bigger allocations than they really need

84. IP packets
• Source and destination addresses
• Protocol number
– 1 = ICMP, 6 = TCP, 17 = UDP
• Various options
– e.g. to control fragmentation
• Time to live (TTL)
– Prevent routing loops

85. IP Datagram
Vers Len TOS Total Length
Identification Flags Fragment Offset
TTL Protocol Header Checksum
Source Internet Address
Destination Internet Address
Options... Padding
Data...
0 4 8 16 19 24 31
Field Purpose
Vers IP version number
Len Length of IP header (4 octet units)
TOS Type of Service
T. Length Length of entire datagram (octets)
Ident. IP datagram ID (for frag/reassembly)
Flags Don’t/More fragments
Frag Off Fragment Offset
Field Purpose
TTL Time To Live - Max # of hops
Protocol Higher level protocol (1=ICMP,
6=TCP, 17=UDP)
Checksum Checksum for the IP header
Source IA Originator’s Internet Address
Dest. IA Final Destination Internet Address
Options Source route, time stamp, etc.
Data... Higher level protocol data
We only looked at the IP addresses, TTL and protocol #

86. IP Routing
• Routing Table
Destination IP address
IP address of a next-hop router
Flags
Network interface specification
Application
Transport
Network
Link
Application
Transport
Network
Link
Network
Link
Source Destination
Router

87. UDP
• Thin layer on top of IP
• Adds packet length + checksum
– Guard against corrupted packets
• Also source and destination ports
– Ports are used to associate a packet with a
specific application at each end
• Still unreliable:
– Duplication, loss, out-of-orderness possible
User Datagram Protocol)

88. UDP datagram
Destination PortSource Port
Application data
0 16 31
ChecksumLength
Field Purpose
Source Port 16-bit port number identifying originating application
Destination Port 16-bit port number identifying destination application
Length Length of UDP datagram (UDP header + data)
Checksum Checksum of IP pseudo header, UDP header, and data

89. Typical applications of UDP
– Where packet loss etc is better handled by
the application than the network stack
– Where the overhead of setting up a
connection isn’t wanted
• VOIP
• NFS – Network File System
• Most games

90. IPv6
• 128 bit addresses
– Make it feasible to be very wasteful with
address allocations
• Lots of other new features
– Built-in autoconfiguration, security options,
…
• Not really in production use yet

91. Network Standard
Network
Architecture
Network Protocol
ISO
OSI
TCP/IP
WIFI/WIMAX Protocols
ITU-T
HTTP