Introduction Computer Networks Lecture Objectives of Todays Lecture
Introduction Computer Networks
Lecture Objectives of Today’s Lecture • In this Lecture, you will learn about a Computer Networks and there goals. You will learn Different types of computer network like PAN, LAN, WAN, MAN and Internet and there division by scale. You will also get familiar with protocols and what is Layer Architecture, history of Open Systems Interconnection (OSI) Model, OSI Reference Model. You will also be introduced to 7 Layers of OSI Reference Model, TCP/IP Reference Model: . By the end of this lecturer, you should be able to understand: • • What is Computer Network and Its Types. What is Layer Architecture? What is OSI Reference Model and what are the 7 layer of OSI Models. Working and responsibilities of each layer works. Devices working on each layer What TCP/IP Reference Model Difference between OSI and TCP/IP Models
Types of Network Personal Area Networks (PAN) PANs (Personal Area Networks) let devices communicate over the range of a person. )ﺍﻟﻤﻨﻄﻘﺔ ﺍﻟﺸﺨﺼﻴﺔ ﺍﻟﺸﺒﻜﺎﺕ( ﺍﻟﺴﻤﺎﺡ ﺃﺠﻬﺰﺓ ﺍﻟﺘﻮﺍﺻﻞ ﻋﻠﻰ ﻧﻄﺎﻕ ﺷﺨﺺ
Types of Network Wide Area Networks(WAN) A WAN (Wide Area Network) spans a large geographical area, often a country or continent. )ﺷﺒﻜﺔ ﺍﻟﻤﻨﻄﻘﺔ ﺍﻟﻮﺍﺳﻌﺔ( ﻣﻨﻄﻘﺔ ﺟﻐﺮﺍﻓﻴﺔ ﻏﺎﻟﺒﺎ ﺑﻠﺪ ﺃﻮ ﻗﺎﺭﺓ ، ﻛﺒﻴﺮﺓ
Types of Network What’s the Internet: “nuts and bolts” view : ﺍﻟﻤﻼﻳﻴﻦ ﻣﻦ ﺃﺠﻬﺰﺓ ﺍﻟﺤﻮﺳﺒﺔ ﺍﻟﻤﺘﺼﻠﺔ PC server v millions wireless laptop smartphone of connected computing devices: – hosts = end systems – running network apps ﻭﺻﻼﺕ ﺍﻻﺗﺼﺎﻝ v communication wireless links wired links § fiber, copper, radio, satellite § transmission rate: bandwidth "ﺍﻟﺼﻮﺍﻣﻴﻞ ﻭﺍﻟﻤﺴﺎﻣﻴﺮ”ﺭﺃﻲ : ﻣﺎ ﻫﻮ ﺍﻹﻧﺘﺮﻧﺖ mobile network global ISP home network ﻣﻔﺎﺗﻴﺢ ﺍﻟﺘﺒﺪﻳﻞ v Packet router switches: forward packets (chunks of data) § routers and switches institutional network regional ISP
Types of Network Classification of Networks By Scale ﺗﺼﻨﻴﻒ ﺍﻟﺸﺒﻜﺎﺕ ﺣﺴﺐ ﺍﻟﻤﻘﻴﺎﺱ
Protocol Layering of airline functionality ticket (purchase) ticket (complain) ticket baggage (check) baggage (claim baggage gates (load) gates (unload) gate runway (takeoff) runway (land) takeoff/landing airplane routing departure airport airplane routing intermediate air-traffic control centers arrival airport layers: each layer implements a service – via its own internal-layer actions – relying on services provided by layer below
OSI Reference Model: 7 Layers
OSI Reference Model Physical Layer The lowest layer, 1 st in the OSI reference model. ﻓﻲ ﺍﻟﻨﻤﻮﺫﺝ ﺍﻟﻤﺮﺟﻌﻲ 1 ST ، ﺃﺪﻧﻰ ﻃﺒﻘﺔ -OSI. The physical layer is concerned with transmitting raw bits over a communication channel. ﻭﺗﺘﻌﻠﻖ ﺍﻟﻄﺒﻘﺔ ﺍﻟﻤﺎﺩﻳﺔ ﺑﺈﺭﺳﺎﻝ ﺍﻟﺒﺘﺎﺕ ﺍﻟﺨﺎﻡ ﻋﺒﺮ ﻗﻨﺎﺓ ﺍﺗﺼﺎﻝ It’s sends bits and receive bits only into the value of 0 and 1. . 1 ﻭ 0 ﺍﻧﻬﺎ ﺗﺮﺳﻞ ﺑﺖ ﻭﺗﻠﻘﻲ ﺑﺖ ﻓﻘﻂ ﻓﻲ ﻗﻴﻤﺔ It actually communicate direct with the various type of communication media. ﻓﻲ ﺍﻟﻮﺍﻗﻊ ﺍﻟﺘﻮﺍﺻﻞ ﻣﺒﺎﺷﺮﺓ ﻣﻊ ﻧﻮﻉ ﻣﺨﺘﻠﻒ ﻣﻦ ﻭﺳﺎﺋﻞ ﺍﻻﺗﺼﺎﻝ Hub works on Physical layer. . ﺍﻟﻤﺮﻛﺰ ﻳﻌﻤﻞ ﻋﻠﻰ ﺍﻟﻄﺒﻘﺔ ﺍﻟﻤﺎﺩﻳﺔ
OSI Reference Model The TCP/IP Reference Model
OSI Reference Model TCP/IP Model Application Layer Application programs using the network Transport Layer (TCP/UDP) Management of end-to-end message transmission, error detection and error correction Network Layer (IP) Handling of datagrams : routing and congestion Data Link Layer Management of cost effective and reliable data delivery, access to physical networks Physical Layer Physical Media
OSI Reference Model Encapsulation and Decapsulation message segment M Ht M datagram Hn Ht M frame M Hl Hn Ht application transport network link physical source link physical switch destination M Ht M Hn Ht Hl Hn Ht M M application transport network link physical Hn Ht Hl Hn Ht M M network link physical Hn Ht M router
OSI Reference Model Encapsulation and Decapsulation
History of Computer Networks (Internet)
History 1972 -1980: Internetworking, new and proprietary nets • • • 1970: ALOHAnet satellite network in Hawaii 1974: Cerf and Kahn - architecture for interconnecting networks 1976: Ethernet at Xerox PARC late 70’s: proprietary architectures: DECnet, SNA, XNA late 70’s: switching fixed length packets (ATM precursor) 1979: ARPAnet has 200 nodes ﺍﻟﺸﺒﻜﺔ ﺍﻟﻔﻀﺎﺋﻴﺔ ﺃﻠﻮﻫﻨﻴﺖ ﻓﻲ ﻫﺎﻭﺍﻱ : 1970 ﺍﻟﻬﻨﺪﺳﺔ ﺍﻟﻤﻌﻤﺎﺭﻳﺔ ﻟﻠﺸﺒﻜﺎﺕ ﺍﻟﻤﺘﺮﺍﺑﻄﺔ - ﺳﻴﺮﻑ ﻭ ﻛﺎﻫﻦ : 1974 ﺇﻳﺜﺮﻧﺖ ﻓﻲ ﺯﻳﺮﻭﻛﺲ ﺑﺎﺭﻙ : 1976 Late 70's ﺷﻨﺎ ، ﺳﻨﺎ ، ﺩﻳﻨﻴﺖ : ﺍﻟﺒﻨﻰ ﺍﻟﻤﻠﻜﻴﺔ : ( ﺗﺒﺪﻳﻞ ﺍﻟﺤﺰﻡ ﻃﻮﻝ ﺛﺎﺑﺖ )ﺍﻟﺴﻼﺋﻒ ﺃﺘﻢ : 70 ﺃﻮﺍﺧﺮ ﺍﻟﻌﻘﺪ 200 ﺃﺮﺑﺎﻧﻴﺖ ﻟﺪﻳﻪ : 1979
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