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Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 1Chapter 3.2: The Internet Protocol IP
Result: ARPANET (predecessor of today's Internet)
Goal:• Interconnection of computers and networks using uniform protocols.
• A particularly important initiative was initiated by the ARPA(Advanced Research Project Agency, with military interests).
• The participation of the military was the only sensible way to implement such an ambitious and extremely expensive project.
• The OSI specification was still in developing phase.
On the Way to Today's Internet
Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 2Chapter 3.2: The Internet Protocol IP
Design objective for ARPANET
• The operability of the network should remain intact even after a largest disaster possible, e.g. a nuclear war, thus high connectivity and packet switching
• Network computer and host computer are separated
ARPA
Advanced Research Projects Agency
ARPANET
1969Subnet
ARPANET
Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 3Chapter 3.2: The Internet Protocol IP
A subnet consists of: • Interface Message Processors
(IMPs), which are connected by rented transmission circuits.
• High connectivity (in order to guarantee the demanded reliability)
Host
IMP
Subnet
IMP-IMP
Protocol
Source IMP todestination IMP protocol
Host-host Protocol
Host-IMPProtocol
A node consists of• an IMP
• a host
Several protocols for the communication between IMP-IMP, host-IMP,…
ARPANET
Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 4Chapter 3.2: The Internet Protocol IP
XDS940
DEKPDP-10
XDS1-7
Stanford ResearchInstitutes (SRI)
Universityof Utah
University of CaliforniaLos Angeles (UCLA)
University ofCalifornia SantaBarbara (UCSB)
ARPANET(December 1969)
IMP
IMPIBM
360/75 IMP
IMP California
The Beginning of ARPANET
Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 5Chapter 3.2: The Internet Protocol IP
SRI
UCSB
UCLA
Utah
WITH
Harvard
Illinois
USC
SRI Utah Illinois WITH
USCUCLA
UCSB
Stanford
HarvardAberdeen
CMU
ARPANET in April 1972 ARPANET in September 1972
Very fast evolution of ARPANET within shortest time:
Evolution by ARPANET
Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 6Chapter 3.2: The Internet Protocol IP
Problem: Interworking!Simultaneously to the ARPANET further (smaller) networks were developed.
All the LANs, MANs, WANs
• had different protocols, media,…
• could not be interconnected at first and were not be able to communicate
with each another.
Therefore:
Development of uniform protocols on the transport- and network level (without a too accurate definition of these levels, in particular withoutexact coordination with the respective OSI levels).Result: TCP/IP networks.
Interworking
Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 7Chapter 3.2: The Internet Protocol IP
Developed 1974:
Transmission Control Protocol/Internet Protocol (TCP/IP)
Requirements:
• Fault tolerance
• Maximal possible reliability and availability
• Flexibility (i.e. suitability for applications with very different requirements)
The result:
• Network protocol IP; (Internet Protocol; connectionless)
• End-to-end protocols TCP (Transmission Control Protocol; connection-oriented) and UDP (User Datagram Protocol; connectionless)
TCP/IP
Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 8Chapter 3.2: The Internet Protocol IP
Application Layer
Presentation Layer
Session Layer
Transport Layer
Network Layer
Data Link Layer
Physical Layer
Application Layer
Transport Layer (TCP/UDP)
Internet Layer (IP)
Host-to-Network Layer
ISO/OSI TCP/IP
TCP/IP and the OSI Reference Model
Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 9Chapter 3.2: The Internet Protocol IP
Both models are based on hierarchical protocol suites
Clear separation between:
1. Services2. Interfaces3. Protocols
Changes of protocols are difficult and sometimes nearly impossible
Protocols were implemented beforespecifying the model. The model was little more than a (not alwayssatisfying) description of the system behavior.
protocols fit the model wellThe model was practically not
transferable to other protocols suites
The OSI reference model was deve-loped before OSI protocols and products
The model was not limited to OSI protocols, but generally usable
Protocol designers often hadnot much experience
OSI: TCP/IP:
No comparably clear separation:
TCP/IP vs. OSI
Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 10Chapter 3.2: The Internet Protocol IP
From the ARPANET to the Internet
• 1983 TCP/IP became the official protocol of ARPANET. ARPANET was
connected with many other USA networks.
• Intercontinental connecting with networks in Europe, Asia, Pacific.
• The total network evolved this way to a world-wide available network (called “Internet”) and gradually lost its early militarily dominated character.
• No central administrated network, but a world-wide union from many individual, different networks under local control (and financing).
• 1990 the Internet consisted of 3,000 networks with 200,000 computers. That was however only the beginning of a rapid evolution.
Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 11Chapter 3.2: The Internet Protocol IP
What does it mean: “a computer is in the Internet”?
- Use of the TCP/IP protocol suite
- Accessibility over an IP address
- Ability to send IP packets
In its early period, the Internet was limited to the following applications:
E-mail electronic mail (partly because the US post was not very reliable and the different time zones made telephone accessibility of thetelephone partner more difficult)
Remote login running jobs on external computers
File transfer exchange of data between computers
Internet
Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 12Chapter 3.2: The Internet Protocol IP
• Until 1990: the Internet was comparatively small, only used by universities and research institutions.
• 1990: The WWW (World Wide Web) - first developed by the CERN for the simplification of communication within the field of high-energy physics -became, together with HTML and Netscape browsers, a from nobody foreseen “killer application”; this was the breakthrough for the acceptance of the Internet.
• Emergence of so-called Internet Service Providers (ISP), i.e. companies, which make their computers available as access points to the Internet.
• Millions of new (predominantly non-academic) users!
• New applications, e.g. E-Commerce
• 1995: Backbones, ten thousands LANs, millions attached computers, exponentially rising number of users
• 1998: The number of attached computers is doubled approx. all 6 months
• 1999: The transferred data volume is doubled in less than 4 months
Evolution of the Internet
Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 13Chapter 3.2: The Internet Protocol IP
Evolution of the Internet
• At the beginning of 2003: (estimated) 171 million of hosts attached to the Internet
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Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 14Chapter 3.2: The Internet Protocol IP
Evolution in Europe
Germany
Europe
Number of Hosts
Date
Nu
mb
er o
f H
ost
s
Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 15Chapter 3.2: The Internet Protocol IP
Internet and Intranet
Internet
• Communication via the TCP/IP protocols
• Local operators control and finance
• Global coordination by some organizations
• Internet Providers provide access points for private individuals
Intranet
• Enterprise-internal communication with the same protocols and applications as in the Internet.
� Computers are sealed off from the global Internet (data security)
� Heterogeneous network structures from different branches can be integrated with TCP/IP easily
� Use of applications like in the WWW for internal data exchange
Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 16Chapter 3.2: The Internet Protocol IP
• Promotes communication and the information and data exchange
• In national and international networks
• in particular for institutions and persons from science, research, education and culture
Gigabit-Wissenschaftsnetz (G-WIN)
• Packet switching, on basis of SDH
• Network services
• Connection to international networks, e.g. to the European scientific network and to USA, Russia or China
The association for the promotion of the German research network: Verein zur Förderung einesDeutschen Forschungsnetzes e.V. (DFN)
Gigabit-Wissenschaftsnetz
Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 17Chapter 3.2: The Internet Protocol IP
German G-Win
Connection of the G-WIN to• German Telekom AG/T-Online
(34 MBit)
• DE-CIX, central exchange point of the German Internet Providers (1 GBit)
• US-American Internet (2x 622 MBit)
• European scientific network GÉANT (2.5/10 GBit)
Stuttgart
Leipzig
Berlin
Frankfurt
Karlsruhe
Garching
Kiel
Braunschweig
Dresden
Aachen
RegensburgKaiserslautern
Augsburg
Bielefeld
Hannover
Erlangen
Heidelberg
Ilmenau
Würzburg
Magdeburg
Marburg
Göttingen
Oldenburg
Essen
St. Augustin
Rostock
Global Upstream
GEANT
Hamburg
Core Node10 GBit/s2,4 GBit/s2,4 GBit/s622 MBit/s
Lehrstuhl für Informatik 4
Kommunikation und verteilte Systeme
Page 18Chapter 3.2: The Internet Protocol IP
GÉANT
• European research network since 2001 (predecessor: TEN-155)
• 2,5 GBit/s Backbone, upgrade to 10 GBit/s (2003)
• Connects more than 30 countries
European scientific network GÉANT