Chapter 1 1

 Introduction to Networking  Fundamental Network Characteristics  Type and Sizes of Networks  Network Performance issues and Concepts  Network Standard and Standard Organizations 2

 A network is a set of hardware devices connected together, either physically or logically to allow them to exchange information. 3

 Connectivity and Communication  Data, Hardware Sharing  Internet Access  Data Security and Management  Performance Enhancement and Balancing  Entertainment 4

 Network Hardware, Software and Setup Costs  Hardware and Software Management and Administration Costs  Undesirable Sharing  Illegal or Undesirable Behavior  Data Security Concerns 5

 Networking Layers ◦ Networking technologies are most often compartmentalized in this manner by dividing their functions into layers, each of which contains hardware and/or software elements.  Networking Models ◦ Open Systems Interconnection (OSI)  Networking Architectures ◦ An architecture is essentially a set of rules that describes the function of some portion of the hardware and software that constitute a stack of layers. 6

 A networking protocol defines a set of rules, algorithms, messages and other mechanisms that enable software and hardware in networked devices to communicate effectively. A protocol usually describes a means for communication between corresponding entities at the same OSI Reference Model layer in two or more devices. 7

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 A connection-oriented protocol is one where a logical connection is first established between devices prior to data being sent. 10

 In a connectionless protocol, data is just sent without a connection being created. 11

 TCP/IP, it has two main protocols that operate at the transport layer of the OSI Reference Model. One is the Transmission Control Protocol (TCP), which is connection- oriented; the other, the User Datagram Protocol (UDP), is connectionless. 12

 Common Names For Messages ◦ Packet/Datagram ◦ Frame/Cell ◦ Protocol Data Unit (PDU) and Service Data Unit (SDU) 13

 Fundamental Message Elements ◦ Header ◦ Data ◦ Footer 14

 Message Transmission Methods ◦ Unicast Messages ◦ Broadcast Messages ◦ Multicast Messages 15

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 Unicast Addressing  Broadcast Addressing  Multicast Addressing 17

 Local Area Networks (LANs)  Wireless Local Area Networks (Wireless LANs or WLANs):  Wide Area Networks (WANs)  Campus Area Networks (CANs):  Metropolitan Area Networks (MANs): ◦ WMANs; IEEE is an example of a WMAN standard  Personal Area Networks (PANs) 18

 Network  Sub-network (Subnet)  Segment (Network Segment) ◦ Collision Domain ◦ Broadcast Domain  Internetwork (or Internet) 19

 Balancing Network Performance with Key Non-Performance Characteristics ◦ Design and Implementation Cost: ◦ Quality ◦ Standardization ◦ Reliability ◦ Expandability and Upgradability ◦ Ease of Administration and Maintenance ◦ Premises and Utility issues 20

 Speed  Bandwidth  Throughput  Latency 21

 Normal Network Overhead  External Performance Limiters  Network Configuration Problems  The Effect of Asymmetry 22

 Simplex Operation  Half-Duplex Operation  Full-Duplex Operation 23

 Bandwidth Reservation  Latency Management:  Traffic Prioritization  Traffic Shaping  Network Congestion Avoidance 24

 Proprietary Standards  Open Standards  De Facto Standards 25

 International Organization for Standardization (ISO):  American National Standards Institute (ANSI):  Information Technology Industry Council (ITIC):  National Committee for Information Technology (NCITS):  Institute of Electrical and Electronics Engineers (IEEE):  Electronic Industries Alliance (EIA):  Telecommunications Industry Association (TIA):  International Telecommunication Union - Telecommunication Standardization Sector (ITU-T):  European Telecommunications Standards Institute (ETSI): 26

 Internet Society (ISOC): ◦ Internet Architecture Board (IAB):  Internet Engineering Task Force (IETF):  Internet Engineering Steering Group (IESG):  Internet Research Task Force (IRTF):  Internet Research Steering Group (IRSG): 27

 Internet Assigned Numbers Authority (IANA) ◦ Asia Pacific Network Information Centre (APNIC): ◦ American Registry for Internet Numbers (ARIN): ◦ Latin American and Caribbean Internet Addresses Registry (LACNIC): ◦ Réseaux IP Européens Network Coordination Center (RIPE NCC):  Internet Corporation for Assigned Names and Numbers (ICANN) 28

 RFC Categories ◦ Proposed Standard / Draft Standard / Standard: ◦ Best Current Practice ◦ Informational ◦ Experimental  29

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