1. An Introduction to Networking Chapter 1, pages 1-22
Lecture 1
An Introduction to Networking
Chapter 1, pages 1-22
Sources: 1) Dean (2012), Network+ Guide to Networks, 6th Edition
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2. Lecture Overview Brief introduction to networking Network Services
LAN versus WAN
Types of architectures
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3. Network Definition
Set of technologies that connects computers to allow communication and collaboration between users.
A group of two or more computer systems linked together to exchange data.
Any device connect to the network referred to as a node.
Any device has a unique logical address (name).
Any device also has a unique physical address (MAC).
A node need NIC to connect to network.
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4. Advantages and Disadvantages of Networking:
Reduce hardware costs.
Sharing application.
Sharing information resources.
Centralized data management.
Connecting people.
Disadvantages:
Loss of autonomy.
Lack of privacy.
Security Threats.
Loss of productivity.
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5. 3 General Categories of Networks
We are focusing on the first one:
1) Local Area Network (LAN)
2) Wide Area Network (WAN)
3) Metropolitan Area Network (MAN)
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6. LAN versus WAN
A LAN is a group of computers located in a relatively small geographical area (like a building or group of buildings)
Typically owned by a single organization
A WAN is used to connect host computers and sites (including other LANs) across a wide geographic area
Collective, distributed ownership consisting of multiple organizations
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7. Local Area Network
Switch PC
Printer ?
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8. Architecture
Networked computers interact with each other in different ways
Computers may have different roles on a network
We refer to the ways in which computers interact with one another on the network and the organizational relationship between the computers as the Logical Architecture
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9. Topology versus Architecture
Architecture - specifies how functions are laid out between the various devices on the network which is independent of the networking technologies being used
How do the devices on the network interact?
Is there a designated “server”?
What is the server’s responsibility?
What is the client’s responsibility?
Topology – the physical arrangement of the devices on the network which is affected by the networking technologies being used
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10. Architecture
3 primary logical architectures (the book just refers to these as “types” of networks)
Host-based
Traditional mainframe / central computer model
Client-based / Peer-to-Peer
Historically most home-based and many small office networks
Client-server
Microsoft model – or what we commonly see today
Fairly powerful clients interacting with some number of servers
Model used on campus
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11. Protocols
For a modern data/communications network to function in a way that most organizations consider to be acceptable:
All devices on the network MUST be able to understand each other regardless of the hardware, manufacturer, system software, and applications being used
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12. Protocols Protocol – set of rules used to communicate
Devices use MANY protocols even during simple data exchanges
Protocols provide format, structure, and meaning to messages
Protocols specify how communication occurs and the form it takes
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13. Protocols and standards
Protocols are typically based on public standards developed by an independent committee - not on standards developed by a single manufacturer
What are standards and why are they important in networking (or for technology use in general)?
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14. LAN Architecture Topologies Transmission medium Layout
Medium access control
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15. LAN topologies
Physical topology : the way in which a network is laid out physically. The actual layout of the wire or media. Two or more devices connect to a link; two or more links form a topology.
Logical topology: Defines how the hosts access the media to send data. Shows the flow of data on a network.
Broadcast
Token passing
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17. Transmission medium - Wired LAN
Network Cables
Unshielded Twisted Pair (UTP) Cable
Shielded Twisted Pair (STP) Cable
Coaxial Cable
Fiber Optic Cable
Ethernet: the most popular cabling technology in LAN.
Ethernet uses
a protocol called
CSMA/CD
Twisted Pair cable
Coaxial cable
Fiber Optic cable
Rj-45 connector
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18. Transmission medium - Wireless LANs
Wi-Fi: wireless LAN standard that offers Ethernet speeds through the use of radio waves instead of wires.
Wifi standards and speeds
Standard
Max Speed
Typical Range
802.11a
54 Mbps
150 feet
802.11b
11 Mbps
300 feet
802.11g
802.11n
100 Mbps
300+ feet
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19. Access Methodology
CSMA/CD
CSMA/CA
Token Passing
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20. standards organization
is any organization whose primary activities are developing, coordinating, revising, amending, reissuing, interpreting, or otherwise producing technical standards that are intended to address the needs of some relatively wide base of affected adopters.
Most standards are voluntary in the sense that they are offered for adoption by people or industry without being mandated in law. Some standards become mandatory when they are adopted by regulators as legal requirements in particular domains.
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21. Standards fall into two categories:
De facto (Latin for “from the fact”): those standards that have just happened, without any formal plan (e.g., IBM PC, Unix)
De jure (Latin for “by law”): formal, legal standards adopted by some authorization body
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22. International organization for standardization - ISO
is the world’s largest developer of voluntary International Standards. International Standards give state of the art specifications for products, services and good practice, helping to make industry more efficient and effective. Developed through global consensus, they help to break down barriers to international trade.
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23. ITU- Telecommunication Standardization Sector (ITU-T
The ITU is a specialized United Nations agency that regulates international telecommunications, including radio and TV frequencies, satellite and telephony specifications, networking infrastructure, and tariffs applied to global communications.
It also provides developing countries with technical expertise and equipment to advance those nations’ technological bases.

24. American national standards institute - ANSI
the Institute is private, non-profitable membership organization supported by a diverse constituency of private and public sector organizations.
ANSI has maintained as its primary goal the enhancement of global competitiveness of U.S. business and the American quality of life by promoting and facilitating voluntary consensus standards and conformity assessment systems and promoting their integrity.

25. These standards ensure that the characteristics and performance of products are consistent, that people use the same definitions and terms, and that products are tested the same way. ANSI also accredits organizations that carry out product or personnel certification in accordance with requirements defined in international standards
ASCII code for encoding English alphabets

26. Institute of Electrical and Electronics Engineers - IEEE
Pronounced as: I-Triple-E.
The IEEE is an international society composed of engineering professionals.
Its goals are to promote development and education in the electrical engineering and computer science fields.
IEEE 802 standards for networks

27. Electronic Industrial Association - EIA
EIA is a trade organization composed of representatives from electronics manufacturing firms across the United States.
EIA began as the Radio Manufacturers Association (RMA) in 1924; over time it evolved to include manufacturers of televisions, semiconductors, computers and networking devices.
EIA/TIA-232

28. the European telecommunications standards institute
Independent, Non-profitable institution.
Consists of telecommunication , producing companies, users , organizations, equipment makers and network operators to develop and produce systems and telecommunication standards in Europe .

29. Other organizations
Asynchronous Transfer Mode : ATM Forum تجمع تقنية النقل غير المتزامن
International, non-profitable companies concerned in ATM switches used in WAN and fast LAN.
Specifications and standards for those switches.

30. Recourses
Dave Novak , Introduction to Networking ,School of Business Administration , University of Vermont
Rehab AlFallaj , lecture notes
online.com/technical_references/pdfs/data_communication s/PhysicalTopology_and_Logical_Topology.pdf
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