TCP/IP fundamentals

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TCP/IP fundamentals

• Unit objectives
• Discuss the evolution of TCP/IP
• Discuss TCP/IP fundamentals

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Topic A

• Topic A Evolution of TCP/IP
• Topic B TCP/IP fundamentals

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Evolution of TCP/IP

• TCP/IP has moved from being a specialty protocol
  used predominantly on UNIX-based minicomputers to
  the protocol of choice for many desktop computers
• It is considered the universal default protocol
  to link dissimilar computer platforms such as
  UNIX, NetWare, OS/2, and Windows

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A brief history

• The three main protocols for the Arpanet were
• NCP (host-to-host communication)
• FTP (file transfer same functions as today)
• Telnet (remote login)
• One year later, NCP was replaced by a new layered
  protocol stack including TCP and IP.
• TCP/IP became an immediate standard

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Activity A-1 page 9-3
Discussing the history of TCP/IP
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RFCs

• Stands for Request for Comments
• Defining document that sets the standards for the
  Internet protocol suite
• RFCs are the mechanism for bringing many new
  protocols and technologies to light. Someone
  writes a new protocol, publishes it as an RFC,
  gets comments and suggestions, uses it in a
  controlled environment and then gets more
  comments, and finally it is accepted or rejected
  as a new addition to the networking field. If
  accepted, it becomes a new standard.
• RFCs are used for information and guidance.

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Activity A-2 page 9-5
Discussing RFCs
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The Internet

• A collection of diverse networks, each connecting
  a range of systems together for a distinct
  purpose
• The common denominator between these networks is
  the use of TCP/IP

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Activity A-3 page 9-7
Discussing the Internet and supported systems
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Topic B
page 9-8

• Topic A Evolution of TCP/IP
• Topic B TCP/IP fundamentals

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TCP/IP fundamentals

• TCP/IP
• The default protocol for UNIX and a de facto
  standard for wide area networking
• Provides utilities to facilitate communications
  and information sharing between dissimilar
  hardware platforms

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Architectural model of TCP/IP

• The OSI model has 7 layers while the TCP/IP model
  is normally seen as having 4. It may be more
  efficient to divide the lowest TCP/IP layer,
  network interface into 2 layers, but
  historically they comprise 1 layer, not 2.
• The book, on page 9-10, asserts that TCP/IP is
  based on a five-layer model. It is not based
  on a 5-layer model. They distinguish the
  TCP/IP model, from the 4-layer DoD model.
  But the TCP/IP model is the DoD model, and it is
  4 layers, not 5. See, e.g., Lamlee, p.100 ff.
  See also, the next 3 slides
• Note, however, that a very small minority of
  sources do attribute a 5-layer model to DoD, but
  there seems to be not historical precedence for
  it.

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Compare Models OSI v. TCP/IP
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Compare Models TCP/IP v. OSI
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Compare Models OSI v. TCP/IP
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But this from a wireless article

• There are a very few articles in which the model
  in the book and to the right is used. It seems
  to want to separate the data-link and physical
  layer functions, as they are separated in the OSI
  model. This is not historically correct, however
  the original version of the TCP/IP model had 4
  layers. Nor does it match subsequent
  developments in the field. When the ISO decided
  that more layers were necessary to accurately
  reflect what is going on in networking
  technology, it went to a 7-layer model, not a
  5-layer one.

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Activity B-1 page 9-11
Discussing the architectural model of TCP/IP
Note that the TCP/IP and the DoD models are
described as 4-layer models even in the book.
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TCP/IP suite

• Core protocols, utilities, and services
  associated with the TCP/IP suite include
• IP (Internet Protocol)
• TCP (Transmission Control Protocol)
• ICMP (Internet Control Message Protocol)
• ARP/RARP
• (Address Resolution Protocol / Reverse Address
  Resolution Protocol)
• UDP (User Datagram Protocol)

continued
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TCP/IP suite - (see pages 9-12 to 9-14)

• Telnet
• HTTP (Hyper Text Transfer Protocol)
• FTP (File Transfer Protocol)
• SFTP (Secure File Transfer Protocol)
• TFTP (Trivial File Transfer Protocol)
• SMTP (Simple Mail Transfer Protocol - sends)
• POP3 (Post Office Protocol 3 receives/holds)
• IMAP (Internet Mail Access Protocol
  store/organize)
• SNMP (Simple Network Management Protocol - agent)
• DNS (Domain Name System)

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TCP/IP suite

• NFS (Network File Services - UNIX)
• NNTP (Network News Transport Protocol)
• NTP (Network Time Protocol)
• SSH (Secure Shell or Secure Socket Shell -
  secure, remote access)
• SCP (Secure Copy Protocol (i.e., from 1 PC on a
  network to another)
• LDAP (Lightweight Directory Access Protocol (a
  protocol to allow simple access to directories)
• IGMP (Internet Group Multicast Protocol allows
  network IP multicasts, - messages to multiple,
  but not all, nodes)
• LPD/LPR (Line Printer Daemon/Line Printer Remote)

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Zero configuration IP networking

• zeroconf
• Enables sharing of files and resources in a
  TCP/IP network without manual (or dynamic)
  configuration
• Is primarily used to create small home networks,
  or to create small networks on the fly
• Lets you do some simple network tasks without
  using some fairly complex utilities that would
  otherwise be required.

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Activity B-2 page 9-15
Discussing the TCP/IP suite
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A client/server environment
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Well-known ports

• Well-known ports are ports at which an
  application listens for a request by default
• For example
• When a computer receives a packet destined for
  port 21, that packet is given to the application
  running the FTP service because the FTP service
  listens on port 21 by default
• The reason for this is that computers perform
  more than one task at a time. If two PCs are
  connected, they need a way to distinguish between
  the processes on each machine that need to
  communicate.

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Unit summary

• Discussed the evolution of TCP/IP
• Discussed TCP/IP fundamentals