Transcript Introduction - Communications

The Internet
Introductory material.
An overview lecture that covers Internet related topics, including a
definition of the Internet, an overview of its history and growth, and
standardization and naming.
1
What defines the Internet ?
1. Use of a globally unique address space based on Internet
Protocol (IP) Addresses
2. Support of the Transmission Control Protocol/Internet
Protocol (TCP/IP) suite for communications
3. Offers end-to-end delivery service for applications
2
A Definition
• On October 24, 1995, the FNC passed a resolution
defining the term Internet.
RESOLUTION: The Federal Networking Council (FNC) agrees that the
following language reflects our definition of the term "Internet".
"Internet" refers to the global information system that -(i) is logically linked together by a globally unique address space
based on the Internet Protocol (IP) or its subsequent
extensions/followons;
(ii) is able to support communications using the Transmission
Control Protocol/Internet Protocol (TCP/IP) suite or its subsequent
extensions/follow-ons, and/or other IP-compatible protocols; and
(iii) provides, uses or makes accessible, either publicly or privately,
high level services layered on the communications and related
infrastructure described herein.
3
History of the Internet
Mid 1960: Papers on “Packet Switching” emerge.
End 1969s: ARPA sponsors the development of a packet-switching
network, called the ARPANET. First four nodes are
UCLA, SRI, U. Utah, UCSB.
1974:
TCP/IP protocols and model are being proposed by
Cerf/Kahn.
1983:
ARPANET adopts TCP/IP. At this time, the ARPANET
has 200 routers.
1984:
NSF funds a TCP/IP based backbone network. This
backbone grows into the NSFNET, which becomes the
successor of the ARPANET.
1995:
NSF stops funding of NSFNET. The Internet does no
longer have a single backbone network
4
Growth of the Internet
700000000
500000000
400000000
300000000
200000000
100000000
Aug-07
Aug-05
Aug-03
Aug-01
Aug-99
Aug-97
Aug-95
Aug-93
Aug-91
Aug-89
Aug-87
Aug-85
Aug-83
0
Aug-81
Number of Internet Hosts
600000000
Time
Source: Internet Software Consortium
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Growth of the Internet
1000000000
10000000
1000000
100000
10000
1000
Aug-07
Aug-05
Aug-03
Aug-01
Aug-99
Aug-97
Aug-95
Aug-93
Aug-91
Aug-89
Aug-87
Aug-85
Aug-83
100
Aug-81
Number of Internet Hosts
100000000
Time
Source: Internet Software Consortium
6
Maps of the ARPANET: 1971
Source: "Casting the Net", page 64; CCR, page 93
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Maps of the ARPANET: 1980
Source:
8
Maps of the Internet
January 1982
This map shows that the
ARPANET evolves into a Network
of Networks
The Internet becomes a
Federation of networks.
Source: wikipeida
9
Maps of the Internet: 1986
Source: wikipeida
10
NSFNET 1991
Source: NCSA
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Internet Map: 2006
Source: no known
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Internet Infrastructure
Regional
Network
(Tier 2)
IXP
Backbone Network
(Tier 1)
local ISP
(Tier 3)
Regional
Network
(Tier 2)
Backbone Network
(Tier 1)
Regional
Network
(Tier 2)
local ISP
(Tier 3)
local ISP
(Tier 3)
IXP
corporate
network
IXP
Regional
Network
(Tier 2)
campus
network
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Autonomous Systems
• The Internet infrastructure consists of a federation of
connected networks that are independently managed
• Each independently managed network is called an
autonomous systems (AS)
• Examples of AS’s:
– University of Toronto Network
– Backbone networks of Sprint, AT&T, and others
– Local Internet Service Providers
– Enterprise networks of institutions, governments, and
corporations
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Internet Infrastructure
• Location where a network (ISP, corporate network, or regional
network) gets access to the Internet is called a Point-ofPresence (POP).
• Locations where Tier-1 or Tier-2 networks exchange traffic are
called peering points.
– Public peering: Traffic is swapped in a specific location,
called Internet exchange points (IXPs)
– Private peering: Two networks establish a direct link to
each other.
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Topology of a Tier-1 NSP
16
Organization of a single node in a Tier-1 network
....
Peering points
Leased links
to customers
3Com
Bay Networks
Modem Bank
Modem Bank
Modem Bank
Modem Bank
Leased links
to customers
Leased links
to customers
Bay Networks
SD
3Com
....
3Com
Modem Bank
....
Links to other
nodes of the
network
....
SD
....
3Com
Metropolitan
area networks
Dial-up and
leased links
to customers
17
Who is Who on the Internet ?
•
•
•
•
•
•
Internet Society (ISOC): Founded in 1992, an international nonprofit professional
organization that provides administrative support for the Internet. Founded in 1992,
ISOC is the organizational home for the standardization bodies of the Internet.
Internet Engineering Task Force (IETF): Forum that coordinates the
development of new protocols and standards. Organized into working groups that
are each devoted to a specific topic or protocol. Working groups document their
work in reports, called Request For Comments (RFCs).
IRTF (Internet Research Task Force): The Internet Research Task Force is a
composed of a number of focused, long-term and small Research Groups.
Internet Architecture Board (IAB): a technical advisory group of the Internet
Society, provides oversight of the architecture for the protocols and the
standardization process
The Internet Engineering Steering Group (IESG): The IESG is responsible for
technical management of IETF activities and the Internet standards process.
Standards. Composed of the Area Directors of the IETF working groups.
Internet Corporation for Assigned Names and Numbers (ICANN): Non-profit
corporation responsible for managing the domain name system, IP address space
allocation, assignment of protocol numbers
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Internet Standardization Process
• Working groups present their work i of the Internet are published as RFC
(Request for Comments).
• RFCs are the basis for Internet standards.
• Not all RFCs become Internet Standards ! (There are >3000 RFCs and
less than 70 Internet standards
• A typical (but not only) way of standardization is:
– Internet Drafts
– RFC
– Proposed Standard
– Draft Standard (requires 2 working implementation)
– Internet Standard (declared by IAB)
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Assigning Identifiers for the Internet
• Who assigns the domain name “tcpip-lab.edu” and who assigns it the
network prefix “128.143.0.0/16”? Who assigns port 80 as the default
port for web servers?
• The functions associated with the assignment of numbers is referred to as
Internet Assigned Number Authority (IANA).
• Early days of the Internet: IANA functions are administered by a single
person (Jon Postel).
Today:
• Internet Corporation for Assigned Names and Numbers (ICANN)
assumes the responsibility for the assignment of technical protocol
parameters, allocation of the IP address space, management of the
domain name system, and others.
• Management of IP address done by Regional Internet Registries (RIRs):
– APNIC (Asia Pacific Network Information Centre)
– RIPE NCC (Réseaux IP Européens Network Coordination Centre)
– ARIN (American Registry for Internet Numbers)
• Domain names are administered by a large number of private
organizations that are accredited by ICANN.
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