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									The Internet

         Every machine
   transparently connected to
          every other
Internetworking : terms of art

   ? An Internet: A network of networks of
      computer hosts able to seamlessly
      communicate - usually through the
      Internet Protocol (IP) and services

  Enterprise Internet: An          The Internet:
     Internet within an              More than
     organization                    50,000
     Public Data Internet:           together
       Internet services
       made available to the
     Who Uses The Internet ?

? Institutions of all kinds - academic, government and
   ? to allow their staff to collaborate with peers
   ? to rapidly coordinate complex, dispersed worldwide activities
   ? to gather and share information
   ? by interconnecting their enterprise networks via Internet backbone
? Professional communities of all kinds - especially
  research and development organizations
? Business enterprises which specialize in providing or
  collecting information
? General public via local access providers and gateways
  to commercial public e-mail carriers and other kinds of
 Internet Maintenance and
  ?1979 Internet Configuration Control
              • to guide the technical evolution

  ?1983 Internet Architecture Board (IAB)

        IETF                                       IRTF
to explore current trouble            looks long term usability
areas and offer possible              and explores the
solutions                             development of new technologies
Internet Maintenance and

?1993        Cooperative management

        • INTERNIC (Internet Network Information Centre)

        • Registration Services

        • Assignment of IP addresses
Internet Standard Domain
 The NIC has specified a set of standard top-
 level domain names that form the basis of
 both a geographical and non-geographical
 naming system
       – com commercial organisations
       – edu educationall organisations
       – gov government institutions
       – mil military groups
       – net major network support centres
       – org organisations other than the above
       – int international organisations
       – country code two character identifier for a
         country in the geographical scheme
Domains and Sub Domains
?A Domain represents a country name ,
 network , organisation etc.

?A Sub Domain indicates a sub
 categorisation as a province ,
 subnetwork , department etc.
Host Names & Internet

?In order to uniquely identify a host on the
 Internet, each host is assigned a unique IP
 address. The IP address is a 32-bit code,
 divided into four parts : eg,
?A host name is made up of domain names,
 separated by periods : eg,
?A Domain Name System (DNS) service
 translates a host name to an IP address.
Domain & IP addresses for NICNET

?Class B Internet Address

   Possible Internet Hosts on NICNET ~ 65,000
Expanding Internet : New


       •Internet 2
The mail through Internet
(done by Mail Transfer Agent)

Some common protocols for email delivery :

?SMTP (Simple Mail Transfer Protocol)
?IMAP (Interactive Mail Access Protocol)
?POP (Post Office Protocol)
?UUCP (Unix to Unix Copy Protocol)
POP (Post Office Protocol)

is a store-and-forward protocol. With
POP, the dial-up IP user obtains an
account on a system with dedicated
connection (POP Server) and then
connects this system with their own
machine (POP Client) and transfers
mail for the client.
E-Mail : Other Possibilities

        Apart from the normal mail
transactions, it is also possible to have
access to other Internet tools like archie, ftp
and gopher through email.

      The email facility may also be used
more effectively by harnessing the world of
mailing lists, discussion groups or
LISTSERVs on almost any subject.
Internet Connectivity

?Mail only connection
        The simplest way to get Internet E-mail
        link is through UUCP connectivity to any
        of the NICNET nodes on dial-up. The
        ‘mail only connections’ are links that
        enable you to send and receive
        electronic mail and Bulletin Board
Internet Connectivity

?Shell Account
        Dial-up terminal connection links you
        to an Internet node of NICNET as a
        terminal and set up a shell account
        which uses a UNIX command line . The
        Internet access / navigation softwares
        (telnet , ftp, gopher, archie, etc.) are
        run on the NICNET node .
 Internet Connectivity

       On demand direct connection - A variant of
       TCP/IP designed for PCs connected through
       telephone lines is called the Serial Line
       Interface Protocol (SLIP) or the Point to
       Point Protocol (PPP) . With one of these a
       high speed ( 9600 baud or preferably 14,400
       baud ) modem connection to an internet site
       of NICNET node one can have a link that
       makes one’s computer a full Internet
       participant .
Serial Line Internet Protocol (SLIP)

?SLIP, Serial Line IP, is currently a de facto
 standard, commonly used for point-to-
 point serial connections running TCP/IP.
?It is merely a packet-framing protocol
?It provides no addressing, packet type
 identification, error detection/correction or
 compression mechanisms.
?Easy to implement.
SLIP (Cont’d.)

? commonly used on dial-up links and
 sometimes for dedicated serial links
?usually used with line speeds between
 1200bps and 19.2Kbps
?useful for allowing mixes of hosts and routers
 (host-host, host-router or router-router) to
 communicate with one another
?max. packet size : 1006 byte datagrams
 (including IP# + headers) - Berkeley Unix
 specification [no standard SLIP specs. Av.]
Point to Point Protocol (PPP)

?A standard method for transporting
 multi-protocol datagrams over point-to-
 point links
?PPP provides a common solution for
 easy connection of a wide variety of
 hosts, bridges and routers.
?Provides error detection/correction and
 data compression and allows higher
The growth of Internet is not
 a fluke or a fad, but the
 consequence of unleashing
 the power of individual

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