1 computer networks and internets spring 2005 assistant professor jainshing liu
TRANSCRIPT
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Computer Networksand Internets
Spring 2005
Assistant Professor JainShing Liu
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NetworksNetworks
What is a network? electric net, telephone net, computer net
Network architecturesNetwork payload (voice net, data network)Network protocolsCircuit-switching vs. packet switching
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NetworksNetworks
Telephone net
EndOffice
PBX
Ext. 200
555-6089 (10 lines)
555-6201
555EndOffice
400-1547 400-2016
400
EndOffice
900
tandemswitchtandem
switchCarrier network
trunk
twist pair
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NetworksNetworks
Computer net
LAN
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You Will LearnYou Will Learn
Using and Building Internet Applications
(Part I)Motivation and toolsNetwork programming and Applications
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You Will Learn (ctn.)You Will Learn (ctn.)
Data Transmission (Part II)Transmission mediaLocal asynchronous communication (RS-232)Long-Distance communication
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You Will Learn (ctn.)You Will Learn (ctn.)Packet Transmission (Part III)
Packet, frames, and error detectionLAN technologiesWAN technologiesProtocols and layering
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You Will Learn (ctn.)You Will Learn (ctn.)Internetworking (Part IV)
Concepts and ProtocolsInternet Protocol (IP) datagram and ForwardingAddress binding (ARP)Internet control messages (ICMP)User Datagram Protocol (UDP)Transmission Control Protocol (TCP)Network Address Translation (NAT)Internet Routing
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You Will Learn (ctn.)You Will Learn (ctn.)
Network applications (Part V)Client-server paradigm, Socket InterfaceDomain name system (DNS)Voice over IP (VoIP)E-mail, File transfer (FTP), Remote login
(TELNET)Email transfer (SMTP)Web technologies and protocolsSNMP
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What You Will NOT LearnWhat You Will NOT Learn
Commercial aspectsProductsVendorsPricesNetwork operating systems
How to purchase / configure / operateHow to design / implement protocol software
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Ch 1. Introduction
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Growth of the InternetGrowth of the Internet
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Growth of Computer Networking
Growth of Computer Networking
Computer networks are everywhereAdvertising, shopping, …
An entire industry has emerged that develops networking technologies, products, and services
Produces a strong demand in all jobs for people with more networking expertise
Programmers are expected to design network application software
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Ch 2. Motivation and Tools
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Motivation for NetworkingMotivation for Networking
Information sharingResource sharing
Computing powerPeripheral devices such as a printer or a diskHuman power
Interaction among cooperative application programs
E.g., earthquake alarm
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ConfigurationsConfigurations
IP addressSubnet MaskDefault gatewayDNS server
Internet
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Internet
Internet ToolsInternet Tools
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Internet ToolsInternet ToolsPing
ping 163.23.1.73 (or ping mail.dyu.edu.tw)
Pinging 163.23.1.73 with 32 bytes of data:Reply from 163.23.1.73: bytes=32 time=2ms TTL=249Reply from 163.23.1.73: bytes=32 time=2ms TTL=249Reply from 163.23.1.73: bytes=32 time=2ms TTL=249Reply from 163.23.1.73: bytes=32 time=1ms TTL=249Ping statistics for 163.23.1.73: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),Approximate round trip times in milli-seconds: Minimum = 1ms, Maximum = 2ms, Average = 1ms
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Internet ToolsInternet Tools traceroute (tracert for MS Windows)
tracert www.nctu.edu.tw
Tracing route to mail.dyu.edu.tw [163.23.1.73] over a maximum of30 hops: 1 <1 ms <1 ms <1 ms 2sch-g.pu.edu.tw [140.128.19.254] 2 <1 ms <1 ms <1 ms ssrccc-mgt.pu.edu.tw [140.128.20.254] 3 1 ms <1 ms <1 ms frouter1.pu.edu.tw [140.128.30.253] 4 2 ms 1 ms 1 ms 140.128.251.42 5 2 ms 2 ms 2 ms 140.128.251.33 6 13 ms 12 ms 13 ms 163.23.32.254 7 2 ms 1 ms 2 ms mail.dyu.edu.tw [163.23.1.73]Trace complete.