(chapter 03 OSI ?? ??? ???)

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• ??? ????
• PART 01 ??
• (chapter 03 OSI ?? ??? ???)
• ???
• E-mail htlim_at_dongseo.ac.kr
• Home page http//kowon.dongseo.ac.kr/htlim

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Chapter 03 OSI ?? ??? ???

• OSI ?? ??
• 3.1.1 ??
• ???? ??? ????? ???? ?? ??? ?? ??? ?? ??
• ??? ?? ?? ??? ??
• 19790?? ?? ?? ??? ??(ISO)? ???? ??? ????
• ????? ?? ????? ???? ????(OSI)? ???? ??? ??

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Chapter 03 OSI ?? ??? ???

• ?? 3.1

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Chapter 03 OSI ?? ??? ???

• Protocol Stack? ?
• ???? ?? (Protocol Layers)
• Networks are complex!
• many pieces
• hosts
• routers
• links of various media

• applications
• protocols
• hardware, software

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Chapter 03 OSI ?? ??? ???

• ?? ??? ??

• a series of steps

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Chapter 03 OSI ?? ??? ???

• ? ??? ???? ??

intermediate air traffic sites
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Chapter 03 OSI ?? ??? ???

• ? ???(layering)? ????
• ??? ???? ??? ?
• explicit structure allows identification,
  relationship of complex
• systems pieces
• ???? ?? ? ??? ?? ??.
• change of implementation of layers service
  transparent to
• rest of system
• e.g., change in gate procedure doesnt affect
  rest of system

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Chapter 03 OSI ?? ??? ???

• OSI model
• OSI ??? ?? ?? ??? ??? ??? ???(open system)
  ? ???? ? ??? ????? ??
• 7???? ??
• ??(Physical) ??
• ?????(Datalink) ??
• ????(Network) ??
• ?????(Transport)
• ??(Session) ??
• ??(Presentation) ??
• ??(Application) ??

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Chapter 03 OSI ?? ??? ???

• 3.1.2 ????
• ?? 3.2

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Chapter 03 OSI ?? ??? ???

• N??? ???? ???
• ???? ??? ???? ????
• ???? ???? ???? ??? ???? ?????
• ????? ??
• ????(N1)? ???(N)? ??? ???(service user)? ?? ????
  ??? ???(service provider)
• ??? ???? ?? ?? ??? N ??? ?????(primitive)

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Chapter 03 OSI ?? ??? ???

• Nested Protocol Header

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Chapter 03 OSI ?? ??? ???

• 3.1.3 OSI 7??
• OSI 7??
• ?? ??(Physical Layer)
• ?? ?? ???? ??? ??? ???? ??
• ??? ?? ??(Data Link Layer)
• ?? ??
• ?? ??
• ?? ??
• ??? ??
• ???? ??(Network Layer)
• routing, addressing ??

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Chapter 03 OSI ?? ??? ???

• ????? ??(Transport Layer)
• ???(end-to-end) ???? ??
• ??? ??? ?? ??? ?? ????? ??
• ?? ??(Session Layer)
• ?? ?? ???(duplex), ???(half-duplex),
  ????(simplex)
• checkpoint ????? ??
• ?? ??(Presentation Layer)
• ??? ??? ??? ??? ??
• ???? ?????? ???? ??
• ?? ??(Application Layer)
• ?? ?? ????(FTAM File Transfer Access and
  Management)
• ?? ??(VT Virtual Terminal) ????

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Chapter 03 OSI ?? ??? ???

• ??? ???? ??
• Transmission and Control Protocol/ Internet
  Protocol
• TCP/IP ? ??? ??? ????? ??? ? ????? ???? ?? ?????
  ???? ?? ????
• ???? ??? ?? ???? TCP/IP ???? ??
• TCP/IP? ???? ??? ????? ???
• ?? 3.3

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Chapter 03 OSI ?? ??? ???

• ???? ??
• ?????? ???? ????(Arpanet)? ??? ?????? ??
• 1970?? ?? TCP/IP ???? ??
• 1980?? ?? ?????? ????? NSFNET? ????? ??? ???
  ????(Internet)?? ????? ??? ??
• ??? ??
• ?????? ?? ??? ?? ????? ??? ?? ?? IP ??? ??
• ? kowon.dongseo.ac.kr, 203.241.176.13
• ???? ?? ????? ID _at_ ???? IP ??
• ? htlim_at_kowon.dongseo.ac.kr
• ??? ?? ?? ??? ?? . ?? ?? . ?? ?? . ?? ??---gt ???
  ???? ??

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Chapter 03 OSI ?? ??? ???

• ??? ??(Domain Name)? ?

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Chapter 03 OSI ?? ??? ???

• ??? ???? ??(Internet protocol stack)
• ??(application) ???? ????? ??
• ftp, smtp, http
• ?????(transport) host-host data transfer
• tcp, u?
• ????(network) ????? ???? ???
• ???
• ip, routing protocols
• ??(link) ?? ???? ????? ??? ??
• ppp, ethernet
• ??(physical) bits on the wire

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Chapter 03 OSI ?? ??? ???

• ??? ??? ??(logical communication)

• ? ??
• distributed
• ???(entities)? ? ??? ??? ??
• ???? ?? ??? ?? ??(peer)? ???? ???? ?? ??? ??

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Chapter 03 OSI ?? ??? ???

• Layering ???(logical) communication

• ? ?????(transport)
• App.?? ??? ??
• ????? ????? ? ??? ?? ??, ??? ?????? ??
• ????? ????? ? peer?? ??
• peer? ack???? ???
• analogy post office

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Chapter 03 OSI ?? ??? ???

• Layering ???(physical) communication

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Chapter 03 OSI ?? ??? ???

• ???? ??? ? ???
• ? ??? ?????? ???? ??? ??? ??? ??? ??? ?? ?? ???
  ??
• ???? ??? ??? ?? ???? ??

source
destination
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Chapter 03 OSI ?? ??? ???

• Internet History
• 1961-1972 ?? packet-switching ??

• 1972
• -ARPAnet? ??
• -NCP (Network Control Protocol)
  
  
• first host-host protocol
• -first e-mail program
• -ARPAnet has 15 nodes

• 1961 queueing theory? packet-switching? ???? ??
  (Kleinrock)
• 1964 ????? packet-switching ??
• 1967 Advanced Reearch Projects Agency? ARPAnet
  ??
• 1969 first ARPAnet? ??

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Chapter 03 OSI ?? ??? ???

• Internet History
• 1972-1980 Internetworking, ??? ?? ????

• 1970 ALOHAnet satellite network in Hawaii
• 1973 Metcalfes PhD thesis proposes Ethernet
• 1974 Cerf and Kahn - architecture for
  interconnecting
• networks
• late70s proprietary architectures DECnet, SNA,
  XNA
• late 70s switching fixed length packets (ATM
  precursor)
• 1979 ARPAnet has 200 nodes

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Chapter 03 OSI ?? ??? ???

• Internet History
• 1980-1990 ??? ????, ????? ??

• new national networks Csnet, BITnet, NSFnet,
  Minitel
• 100,000 hosts connected to confederation of
  networks

• 1983 deployment of TCP/IP
• 1982 smtp e-mail protocol defined
• 1983 DNS defined for name-to-IP-address
  translation
• 1985 ftp protocol defined
• 1988 TCP congestion control

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Chapter 03 OSI ?? ??? ???

• Internet History
• 1990s ???, WWW

• 1990?? ? WWW
• hypertext Bush 1945, Nelson 1960s
• HTML, http Berners-Lee
• 1994 Mosaic, later Netscape
• late 1990s commercialization of the WWW

• Late 1990s
• est. 50 million computers on Internet
• est. 100 million users
• backbone links runnning at 1 Gbps

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Chapter 03 OSI ?? ??? ???

• Residential access point to point access
• Dialup via modem
• up to 56Kbps direct access to router
  (conceptually)
• ISDN intergrated services digital network
  128Kbps all-digital connect to router
• ADSL asymmetric digital subscriber line
• up to 1 Mbps home-to-router
• up to 8 Mbps router-to-home

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Chapter 03 OSI ?? ??? ???

• Residential access cable modems
• HFC hybrid fiber coax
• asymmetric up to 10Mbps upstream, 1 Mbps
  downstream
• network of cable and fiber attaches homes to ISP
  router
• shared access to router among home
• issues congestion, dimensioning
• deployment available via cable companies, e.g.,
  MediaOne

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Chapter 03 OSI ?? ??? ???

• Institutional access local area networks
• company/univ local area network (LAN) connects
  end system to edge router
• Ethernet
• shared or dedicated cable connects end system and
  router
• 10 Mbs, 100Mbps, Gigabit Ethernet
• deployment institutions, home LANs soon

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Chapter 03 OSI ?? ??? ???

• Wireless access networks
• shared wireless access network connects end
  system to router
• wireless LANs
• radio spectrum replaces wire
• e.g., Lucent Wavelan 10 Mbps
• wider-area wireless access
• CDPD(Cellular Digital Packet data) wireless
  access to ISP router via cellular network

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Chapter 03 OSI ?? ??? ???

• ??? ?? ??
• ??? ????
• ???? ??? ??? ??
• ?? ??(??, ???, ???)?? ??
• ??? ?? ???? LAN(Local Atrea Network)? ??
• ????? ?? ?? 56K BPS(Bit/second)??
• ??? ??? ??? ??
• ???? ???? ??
• SLIP(Serial Line Internet Protocol) ?
  PPP(Point-to-Point Protocol) ??
• ??? ??? ??? ??? ??
• ???(Ethernet)
• VDSL(Very high-data rate Digital Subscriber Line)
• ADSL(Asymmetric Digital Subscriber Line)