Transcript Internet2

Series of lectures
“Telecommunication networks”
Lecture#05
Data transmission
networks
Instructor: Prof. Nikolay Sokolov, e-mail: [email protected]
The Bonch-Bruevich Saint-Petersburg State
University of Telecommunications
Definition
At present time "data transmission" term is often used for
description of the different information exchange processes.
Earlier this term was used for information intended for
processing in the computer or for information already
processed by the computer techniques means. In the ITU-T
X.902 Recommendation (edition of the 1995) the "data" term
definition was given as follows: "The representation forms of
information dealt with by information systems and users
thereof". Transformation of the term is related to processes
of integration and convergence in the modern
infocommunication system. In some cases, term "information
and communications technology" (ICT) is used instead of
infocommunications".
First data transmission systems
for the mainframe
Data Link
Mainframe
Mainframe
a) Connection between two mainframes
Terminal
Subscriber Line
Terminal
Subscriber Line
Mainframe
Terminal
Subscriber Line
b) Connections for terminals
Internet Engineering Task Force (IETF)
The Internet Engineering Task Force (IETF) is a large open
international community of network designers, operators,
vendors, and researchers concerned with the evolution of the
Internet architecture and the smooth operation of the Internet.
It is open to any interested individual. The IETF Mission
Statement is documented in RFC 3935 (RFC – Request for
Comments).
The goal of the IETF is to make the Internet work better. The
mission of the IETF is to produce high quality, relevant technical
and engineering documents that influence the way people design,
use, and manage the Internet in such a way as to make the
Internet work better. These documents include protocol
standards, best current practices, and informational documents
of various kinds.
Internet (RFC 3935 )
The Internet: A large, heterogeneous collection of
interconnected systems that can be used for communication
of many different types between any interested parties
connected to it. The term includes both the "core Internet"
(ISP networks) and "edge Internet" (corporate and private
networks, often connected via firewalls, NAT boxes,
application layer gateways and similar devices). The
Internet is a truly global network, reaching into just about
every country in the world. The IETF community wants
the Internet to succeed because we believe that the
existence of the Internet, and its influence on economics,
communication, and education, will help us to build a
better human society.
Definition related to Internet (1)
1. Domain. Every country is assigned a certain code marking two-three Latin letters
long, which is called first level domain. If the address ends with letters "ru", then
corresponding site is situated in the Russia’s domain. There are also first level
domains, which are related not with geography, but to the site orientation. For
example, letters "com" are used for the commercial organizations, and letters "edu"
are used for the educational institutes. Domains of the second level are rented to the
organizations and private persons. Domain of the second level, as well as the next
levels, must consist of the digits and Latin letters. When choosing domain of the
second level for their site, as a rule, one usually strives to find a word that will
correspond to the organization’s name, produced goods or orientation of activity,
and also is easy to read and remember. Second level domain possessor has a
capability of creating unlimited number of third and so on level addresses.
2. Search engine. This system serves as an instrument for the information search in
the Internet. Search engines differ in scope on local (for example, limited to national
domain or certain language) and global (in particular, they qualitatively conduct
USA sites search, where the significant part of the information resources is placed).
Most part of the search engines does not require knowledge of the special request
language. It’s enough to point out in the inquiry line a few key words determining
the area of the user’s interest. Texts are the main object for the search engines.
Definition related to Internet (2)
3. Site, Web-site. Site is the place in the Internet, which is determined by its address, has its
own possessor and consists of several web-pages, which are apprehended as a single whole.
Usually web-pages have identical design. There is no strict definition to the term “site”. For
example, some parts of the big sites can be perceived and even defined by their possessors as
individual sites.
4. Server, web-server. This term is used in three different meanings. Firstly, sometimes it is
equivalent to the term "site". Secondly, computer, which provides site operation, is called
server. Thirdly, sometimes the program which provides Web-site operation is called so.
Server’s main task is the transmission of the site’s pages via http protocol.
5. Web-page. Web page represents independent part of the Web-site. This document has
unique address, which is well known by the abbreviation URL.
6. Host. There are several interpretations of this term. Mostly, any device (including PC),
connected to the Internet and using TCP/IP protocol stack is called host. Rarely, by host
mainframe is meant.
7. Web-browser. This program provides user with abilities of navigating and reviewing the
Web-resources, downloading files and also with a number of other operations.
8. HTTP. Http protocol determines principles of the Web-pages transmission via the Internet
network. At first http protocol was used only for transmission of the html-documents. At the
present time, it is possible to transmit any information, including static images, sound and
video by means of the http.
Definition related to Internet (3)
9. HTML. In that language browser (navigator) is informed just what the text and
other elements (pictures, tables and etc) exactly and how should be shown on the
page. HTML is not programming language; it’s used for the special markup of the
text, meant for the publishing in the Internet. HTML language allows cohering
pages by means of links. Existence of the links is an important property of the Web
pages.
10. IP-address. This address is used for the identification of the node in the network
and for determining routing principles. Address consists of the network and host
identifications (network and host ID), assigned by the network administrator.
Network ID is a part of the IP-address, which determines group of the computers
and devices of one logic network. Host ID is a part of the IP-address, which
determines belonging of the computer to the certain network. Usually IP address is
written in form of the four numbers with values from 0 to 255, separated by dots.
11. DNS-server. Main function of these special Web-servers is the storage of
information about IP addresses and its transformation.
12. URL (Universal Resource Locator). This term is interpreted as the address of the
page in the Internet. URL consists of domain name, path to the page on the site and
the name of the page file. As a rule files containing Web-pages have "htm" or "html"
extensions.
Example of the Internet network structure
AS1
AS2
AS3
AS5
AS4
AS – Internet autonomous system
Interconnection of two local networks
R
R
R
R
LAN
LAN
R
R
R
R
R
R – router, LAN – Local Area Network
Internet influence on the
infocommunication system
Internet information system, Internet network
Telecommunication network
Society
Social environment
Individual
Economy
Perspective infocommunication system
Some aspects of the
Internet evolution
Main directions of the Internet development
Users working conditions
improvement
Provision of the new service
types
Creation of the system
management mechanisms
Broadband access
Text translation from
other languages
Security
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Mobility
“Intellectual” help
Introduction of the
rational censorship
Internet2 (1)
Who We Are
Internet2 is a not-for-profit advanced networking consortium
comprising more than 200 U.S. universities in cooperation with 70
leading corporations, 45 government agencies, laboratories and
other institutions of higher learning as well as over 50 international
partner organizations.
Our organization is governed by an executive Board of Trustees
and strategic councils consisting of leaders who represent our
broad membership.
http://www.internet2.edu/
Internet2 (2)
What We Do
Internet2 members leverage our high-performance network and
worldwide partnerships to support and enhance their educational
and research missions.
Beyond just providing network capacity, Internet2 actively engages
our community in the development of important new technology
including middleware, security, network research and performance
measurement capabilities which are critical to the progress of the
Internet.
http://www.internet2.edu/
Internet2 (3)
Why We Do It
We have only begun to discover the potential of Internet
technology, not only to the important work of the research and
education community, but to commerce and business, to healthcare
and science, to the arts and humanities and beyond. Unlike any
other organization of its kind, the Internet2 community pioneers
the use of advanced network applications and technologies, from
their academic inception through their evolution to the commercial
Internet.
http://www.internet2.edu/
Internet2 (4)
Structure of the network Abilene
OC-48c – 2488.32 Mbit/s, OC-192c – 9953.28 Mbit/s, (OC – Optical Carrier)
Protocols (1)
DoD – Department of Defense
Protocols (2)
Protocols (3)
Access to Internet (1)
Access to Internet (2)
Wide area network connection (1)
Wide area network connection (2)
NTE – Network terminal equipment
Switching equipment
Examples of network structure (1)
Examples of network structure (2)
Traffic growth
Traffic
Data
?
Voice
Time
Traffic distribution
In 2010, approximately 140x1018 bytes will be transmitted via networks.
Forecast of the access demands
Households, %
100
80
Sources: Alcatel Telecommunications Review, 2nd Quarter 2003,
Telektronikk, Volume 100, No. 4, 2004.
100 Mb/s
60
24 Mb/s
40
6 Mb/s
1.5 Mb/s
20
Year
1995
2000
2005
2010
2015
2020
2025
Cost of Internet services
Internet in our life
Research company “Yougov” carried out survey among
broadband Internet users in Great Brittan. The main goal
was to define goods and services that citizens will be eager to
sacrifice during economic depression. Approximately 3% of
the respondents were ready to save money by limiting
expenses on Internet access.
About 30% of respondents (near 5 million) were ready to cut
down expenses related to newspapers & magazines, alcohol,
cigarettes but will use Internet. On the other hand, only 60%
of respondents were going to use services from their
Provider. Remainder will find Provider with inexpensive
services.
Note
Some pictures used in this presentation may be found in
“Handbook of Data Communications and Networks” written
by William Buchanan.
Data transmission networks
Questions?
Instructor: Prof. Nikolay Sokolov, e-mail: [email protected]