Introduction to IT InfrastructureCITM-301
Week-1
Khalil A. Abuosba, Ph.D.
Winter 2012
Ryerson University
Part-1: Introduction/Essential ConceptsPart-2: The Internet
Lecture OutlinePart-1: Essential Concepts
1.1 – Introduction– Brief history of Data Communications, Communications, Information
Systems and the Internet
1.2 - Data Communications Networks– Network components, network types
1.3 - Network Models– OSI model, Internet model, transmission via “layers”
1.4 - Network Standards– Standards making, common standards
1.5 - Future Trends– Pervasive networking, integration of voice, video, and data, new
information services
1.6 – Implications for Management
Part-2: The Internet
Definition: Data
• Date are a collection of row facts, statistics, and/or observations.
Definition: Information
• A collection of facts organized in such a way/context that they have additional value/meaning beyond the value of the facts themselves.
Business Data Communications, Stallings 5
Information & Communication
• Networking is critical to the new corporate structures emerging in today’s businesses
• Benefits of good networks– make geographically dispersed companies
more manageable– help top-heavy companies trim down middle
management– help companies break down barriers between
divisions.– make automation and quality enforcement
easier to implement.
Definition: Networking Architecture
• Networking architecture refers to an organized set of documents that defines a protocol (a set of logical rules that devices must follow to communicate) as well as defines some logical and physical networking requirements.
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Information Age
• First Industrial Revolution– Introduction of machinery
– New organizational methods
– Changed the way people worked
• Second Industrial Revolution – Information Age– Introduction of computers
– Introduction of networking and data communication
– Changed the way people worked again
• Faster communication Collapsing Information lag
• Brought people together Globalization
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The Collapsing Information Lag
1900 1950 20091850
large quantities of information transmitted in a fraction of a second
telegraph
Information took days or weeks to be transmitted
Information transmitted in minutes or hours
Historical developments in electronic communications
sped up the rate and volume of transmission of information
growth of telecommunications and especially computer networks Globalization
of networks
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Three Parts to Understanding Networking
1. Concepts of networking– How data moves from one computer to another over a
network
– Theories of how networks operate
2. Technologies in use today– How theories are implemented, specific products
– How do they work, their use, applications
3. Management of networking technologies– Security
– Network Design
– Managing the network
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Advances in Phone Technology
1876
Phone invented
first trans-continental
and transatlantic
phone connections
1915
1919
Strowger (stepper) switch,
rotary dial phones(enabling automatic
connections)
1948
Microwave trunk lines (Canada)
1962
Telstar (Telecommunications
via satellite), Fax services, digital transmission (T-
carriers)
1969
Picturefone (failed
commercially)
1976
Packet-switched data
communications
1984
Cellular telephone
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Regulation of Inventions
1900
millions of phones in use in the US
Regulation began in the USA (ICC)
1934
FCC established
1968
Carterfone court decision allowing non-Bell CPE
1970
MCI wins court case; begins providing some long distance services
1984
Consent decree by US federal court
1996
1996 US Telecom Act
A time for technological change
1885
AT&T
Phone invented (rapid acceptance)
1876
Bell System: de facto monopoly
1910
Deregulation
period
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1984 Consent Decree D
ivestiture of 1/1/84:
RBOC’s
•AT&T broken up into one long distance company (AT&T) and 7 Regional Bell Operating Companies (RBOC’s)
Deregulation: IXC’s and LEC’s• Competitive long distance (IXC) market; MCI & Sprint enter
long distance telephone market (among others)• Local Exchange Carrier (LEC) service markets remained
under RBOC monopoly
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US Telecom Act of 1996
• Replaced all current laws, FCC regulations, 1984 consent decree, and overrules state laws
• Main goal: open local markets to competition
• To date, though, local and long distance competition slow to take hold
– Large IXCs expected to move into the local markets, happening only recently
– Likewise, RBOCs expected to move into long distance markets, happening only recently
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Worldwide Competitive Markets
• Internet market– Extremely competitive with more than 5000 Internet
Service Providers (ISPs) in the US alone.
– Heavy competition in this area may lead to a shake out in the near future.
• World Trade Organization (WTO) agreement (1997)– commitments by 68 countries to open, deregulate or
lessen regulation in their telecom markets
• Multi-national telecom companies– US companies offering services in Europe, South
America
– European companies offering services in USA
Definition: Information System
• A set of interrelated components that collect, manipulate, store, and disseminate data and information and provide a feedback mechanism to meet an objective.
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History of Information Systems
Data communications over phone lines (became
common and mainframes became multi-user systems)
Batch processing mainframes
Networking everywhere
PC LANs become common
1950 1960 1990 20001970 1980
Online real-time, transaction oriented
systems (replaced batch processing. DBMSs become common)
PC revolution
Definition: Distributed Information System
• A distributed information system consists of multiple autonomous computers that communicate through a computer network. The computers interact with each other in order to achieve a common goal.
• “A distributed system is a collection of independent computers that appear to
• the users of the system as a single computer.” [Tanenbaum]
Examples of Distributed Information System
• The world wide web – information, resource sharing
• Clusters, Network of workstations
• Distributed manufacturing system (e.g., automated assembly line)
• Network of branch office computers -Information system to handle automatic processing of orders
• Network of embedded systems
• New Cell processor (PlayStation 3)
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Internet Milestones
Originally called ARPANET, the Internet began as a military-academic network
1969
Worldwide: Over 1 billion
Internet users
20071990
commercial access to the Internet begins
ARPANET splits:• Milnet - for military• Internet - academic,
education and research purposes only
1983
NSFNet created as US Internet backbone
1986
Government funding of the
backbone ends
1994
Net Neutrality
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Net neutrality means that for a given type of content (i.e. email,
web, video, etc), all content providers are treated the same.
Net neutrality prevents ISPs from giving priority to some content
providers, while slowing down others
convergence
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1.2 Data Comm Networks
Broadband Communications
Telecommunications =Transmission of voice, video, and/or data - Implies longer distances- Broad term
Data Communications =Movement of computer information by means of electrical or optical transmission systems
Communications Tasks
Transmission system utilization
Addressing
Interfacing Routing
Signal generation Recovery
Synchronization Message formatting
Exchange management Security
Error detection and correction
Network management
Flow control
The key tasks that must be performed in a data communications system.
• Transmission system utilization - need to make efficient use of transmission facilities typically shared among a number of communicating devices
• Interfacing is required between a device and the transmission system
• once an interface is established, signal generation is required for communication
• Synchronization is required between transmitter and receiver, to determine when a signal begins to arrive and when it ends
• there is a variety of requirements for communication between two parties that might be collected under the term exchange management
• Error detection and correction are required in circumstances where errors cannot be tolerated
• Flow control is required to assure that the source does not overwhelm the destination by sending data faster than they can be processed and absorbed
• Addressing and routing, so a source system can indicate the identity of the intended destination, and can choose a specific route through this network
• Recovery allows an interrupted transaction to resume activity at the point of interruption or to condition prior to the beginning of the exchange
• Message formatting has to do with an agreement between two parties as to the form of the data to be exchanged or transmitted
• Frequently need to provide some measure of security in a data communications system
• Network management capabilities are needed to configure the system, monitor its status, react to failures and overloads, and plan intelligently for future growth.
•
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Basic Communications Model
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.
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Simplified Network Model
WANWAN
LANLAN
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Basic Communications Model
• Example
– Communication between a workstation and a server
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Trends Driving Data Communication
• Traffic growth– Voice & data over Internet Protocol (IP); local
and long distance
• Development of new services– Multimedia on demand and TV distribution
• Advances in technology– Encourage and support increased growth and
new developments
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Key Technology Trends
• Faster and cheaper computing platforms, communications hardware, and software
• Increasingly “intelligent” networks, management and assessment tools
• Growing importance of Internet, intranet and extranet applications
• Increasing use of and dependence on mobile and wireless technology
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Enterprise Networks Drivers
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Enterprise Networks ConvergenceA Three-Layer Model
1. Applications: Seen by end users
– Voice calling, email, and instant messaging
– Group collaboration and relationship management
2. Enterprise Services: Seen by network Manager
– Design, maintenance, and support services
– Authentication, capacity management, and QoS
3. Infrastructure: Enterprise available assets
– Links, LANs, WANs, and Internet connections
– Carry information over data networks
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Unified Communication (UC) Convergence
Web 2.0: Second generation web capabilities
1. User generated content (blogs, wikis, clips, etc.)
2. Desktop –like user interface friendly capabilities
Real-Time Communication (RTC): desktop and mobile software clients functionalities
IP Enabling Contact Centers: Enhance customer contact center functionality and performance
IP Mobility: Remote access technology and mobile employees support
IP Wireless: IP packet extended to support local and wide area wireless communication
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Business Information Requirements
Personal, Workgroup, and Enterprise
Unified Integrated Communications:
• Voice communications
• Data communications
• Image communications
• Video communications
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Components of a Local Area Network
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Network Types (based on Scale) • Local Area Networks (LAN) - room, building
– a group of PCs that share a circuit.
• Backbone Networks (BN) - less than few kms– a high speed backbone linking together organizational LANs
at various locations.
• Metropolitan Area Networks (MAN) - (more than a few kms)– connects LANs and BNs across different locations – Often uses leased lines or other services used to transmit
data.
• Wide Area Networks (WANs) - (far greater than 10 kms)– Same as MAN except wider scale
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LANs and Backbones, Wide Area and Metropolitan Area Networks
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Intranet vs. Extranet
• Intranet– A LAN that uses the Internet technologies within an
organization
– Open only those inside the organization
– Example: insurance related information provided to employees over an intranet
• Extranet– A LAN that uses the Internet technologies across an
organization including some external constituents
– Open only those invited users outside the organization
– Accessible through the Internet
– Example: Suppliers and customers accessing inventory information in a company over an extranet
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Layered Implementation of Communications Functions
Applications
OS
Applications
OS
Multi layer implementation-Breaking down into smaller components-Easier to implement
Single layer implementation-Networking with large components is complex to understand and implement
Applications
OS
Co
mm
un
ication
Applications
OS
Co
mm
un
ication
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1.3 Multi-layer Network Models
• The two most important such network models: OSI and Internet
• Open Systems Interconnection Model– Created by International Standards Organization (ISO)
as a framework for computer network standards in 1984
– Based on 7 layers
• Internet Model– Created by DARPA originally in early 1970’s
– Developed to solve to the problem of internetworking
– Based on 5 layers
– Based on Transmission Control Protocol/ Internet Protocol (TCP/IP) suite
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7-Layer Model of OSI
• Application Layer– set of utilities used by application programs
• Presentation Layer– formats data for presentation to the user
– provides data interfaces, data compression and translation between different data formats
• Session Layer– initiates, maintains and terminates each logical session
between sender and receiver
Physical DataLink Network Transport Session Presentation Application
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7-Layer Model of OSI
• Transport Layer– deals with end-to-end issues such as segmenting the
message for network transport, and maintaining the logical connections between sender and receiver
• Network Layer– responsible for making routing decisions
• Data Link Layer– deals with message delineation, error control and
network medium access control
• Physical Layer– defines how individual bits are formatted to be
transmitted through the network
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Internet’s 5-Layer Model
• Application Layer– used by application program
• Transport Layer – responsible for establishing end-to-end connections,
translates domain names into numeric addresses and segments messages
• Network Layer - same as in OSI model
• Data Link Layer - same as in OSI model
• Physical Layer - same as in OSI model
“Please Do Not Touch Alligators”
Physical DataLink Network Transport Application
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Comparison of Network Models
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Message Transmission Using Layers
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Protocols
• Used by network model layers
• Sets of standardized rules to define how to communicate at each layer and how to interface with adjacent layers
receiversender
Layer N
Layer N-1
Layer N+1
Layer N
Layer N-1
Layer N+1
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Message Transmission Example
OSI Data Encapsulation http://w
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si-model.htm
Protocol Data Unit (PDU)
• The combination of data and control information is a protocol data unit (PDU)
• Typically control information is contained in a PDU header
– control information is used by the peer transport protocol at computer B
• Headers may include:
– source port, destination port, sequence number, and error-detection code
OSI Data Encapsulation http://w
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At any particular layer N, a PDU is a complete message that implements the protocol at that layer. However, when this “layer N PDU” is passed down to layer N-1, it becomes the data that the layer N-1 protocol is supposed to service. Thus, the layer N protocol data unit (PDU) is called the layer N-1 service data unit (SDU).
OSI Data Encapsulation http://w
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At any particular layer N, a PDU is a complete message that implements the protocol at that layer. However, when this “layer N PDU” is passed down to layer N-1, it becomes the data that the layer N-1 protocol is supposed to service.
Thus, the layer N protocol data unit (PDU) is called the layer N-1 service data unit (SDU). The job of layer N-1 is to transport this SDU, which it does in turn by placing the layer N SDU into its own PDU format, preceding the SDU with its own headers and appending footers as necessary.
This process is called data encapsulation, because the entire contents of the higher-layer message are encapsulated as the data payload of the message at the lower layer.
OSI Data Encapsulation http://w
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The job of layer N-1 is to transport this SDU, which it does in turn by placing the layer N SDU into its own PDU format, preceding the SDU with its own headers and appending footers as necessary. This process is called data encapsulation, because the entire contents of the higher-layer message are encapsulated as the data payload of the message at the lower layer.
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Points about Network Layer View
• Layers allow simplicity of networking in some ways – Easy to develop new software that fits each layer– Relatively simple to change the software at any level
• Matching layers communicate between different computers and computer platforms– Accomplished by standards that we all agree on– e.g., Physical layer at the sending computer must
match up with the same layer in the receiving computer
• Somewhat inefficient– Involves many software packages and packets– Packet overhead (slower transmission, processing time)– Interoperability achieved at the expense of perfectly
streamlined communication
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1.4 Network Standards
• Importance– Provide a “fixed” way for hardware and/or software
systems (different companies) to communicate
– 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
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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
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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)
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Major Standards Bodies (Cont.)
• 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 welcome)
– www.ietf.org
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Some Data Comm. StandardsLayer Common Standards
5. Application layerHTTP, 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 layerEthernet (LAN)Frame Relay (WAN)T1 (MAN and WAN)
1. Physical layerRS-232c cable (LAN)Category 5 twisted pair (LAN)V.92 (56 kbps modem)
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1.5 Future Trends
• Pervasive Networking
• Integration of Voice, Video and Data
• New Information Services
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Pervasive Networking
• Means “Networks will be everywhere”
• Exponential growth of Network use
• Many new types of devices will have network capability
• Exponential growth of data rates for all kinds of networking
• Broadband communications
– Use circuits with 1 Mbps or higher (e.g., DSL)
Relative Capacities of Telephone, LAN, BN, WAN, and Internet Circuits.
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Integration of Voice, Video & Data
• Also called “Convergence”– Networks that were previously transmitted
using separate networks will merge into a single, high speed, multimedia network in the near future
• First step largely complete– Integration of voice and data
• Next step – Video merging with voice and data
– Will take longer partly due to the high data rates required for video
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New Information Services
• World Wide Web based– Many new types of information services becoming
available
• Services that help ensure quality of information received over www
• Application Service Providers (ASPs)– Develop specific systems for companies such as
providing and operating a payroll system for a company that does not have one of its own
• Information Utilities (Future of ASPs)– Providing a wide range of info services (email, web,
payroll, etc.) (similar to electric or water utilities)
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1.6 Implications for Management• Embrace change and actively seek to use new
aspects of networks toward improving your organization– Information moved quickly and easily anywhere and
anytime
– Information accessed by customers and competitors globally
• Use a set of industry standard technologies– Can easily mix and match equipment from different
vendors
– Easier to migrate from older technologies to newer technologies
– Smaller cost by using a few well known standards
Part-2: The Internet
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