The document provides an overview of the history and evolution of the internet. It describes the Victorian telegraph network in the 1840s as a precursor technology. In the late 1960s, ARPANET was created connecting five nodes and using the TCP specification developed by Vint Cerf in 1974. The internet continued growing through the 1980s and 1990s with the introduction of TCP/IP, browsers, HTML, and the World Wide Web, enabling new applications and fueling the rise of e-commerce.

1. Internet History
and Growth
KOS 1110
COMPUTER IN SCIENCE

2. What Was the
“Victorian Internet”





The Telegraph - invented in the
1840s
Signals sent over wires that were
established over vast distances
Used extensively by the U.S.
Government during the American
Civil War, 1861 - 1865
Morse Code was dots and dashes,
or short signals and long signals
The electronic signal standard of
+/- 15 v. is still used in network
interface cards today

3. Famous Quote From
Sir Isaac Newton

“If I have been able to see farther than
others, it was because I stood on the
shoulders of giants.”

4. What Is the Internet?


A network of networks, joining many government,
university and private computers together and providing
an infrastructure for the use of E-mail, bulletin boards, file
archives, hypertext documents, databases and other
computational resources
The vast collection of computer networks which form and
act as a single huge network for transport of data and
messages across distances which can be anywhere from
the same office to anywhere in the world

5. What is the Internet?



The largest network of networks in the world
Uses TCP/IP protocols and packet switching
Runs on any communications substrate
From Dr. Vinton Cerf,
Co-Creator of TCP/IP

6. Brief History of the Internet


1968 - DARPA (Defense Advanced Research Projects Agency)
contracts with BBN (Bolt, Beranek & Newman) to create ARPAnet
1970 - First five nodes:







UCLA
Stanford
UC Santa Barbara
U of Utah, and
BBN
1974 - TCP specification by Vint Cerf
1984 – On January 1, the Internet with its 1000 hosts
converts en masse to using TCP/IP for its messaging

7. *** Internet History ***

8. A Brief Summary of the
Evolution of the Internet
First Vast
Computer
Network
Silicon Envisioned
Chip
A
1962
Mathematical 1958
Theory of
Communication
Memex
1948
Conceived
Packet
Switching
Invented
1964
Hypertext
Invented
1965
TCP/IP
Created
ARPANET
1972
1969
Mosaic
WWW Created
Internet Created
1993
Named
1989
and
Goes
TCP/IP
1984
Age of
eCommerce
Begins
1995
1945
1945
1995

9. From Simple, But Significant Ideas Bigger Ones Grow
1940s to 1969
We will prove that packet switching
works over a WAN.
Hypertext can be used to allow
rapid access to text data
Packet switching can be used to
send digitized data though
computer networks
We can accomplish a lot by having a
vast network of computers to use for
accessing information and exchanging ideas
We can do it cheaply by using
Digital circuits etched in silicon.
We do it reliably with “bits”,
sending and receiving data
We can access
information using
electronic computers
1945
1969

10. From Simple, But Significant Ideas Bigger Ones Grow
1970s to 1995
Great efficiencies can be accomplished if we use
The Internet and the World Wide Web to conduct business.
The World Wide Web is easier to use if we have a browser that
To browser web pages, running in a graphical user interface context.
Computers connected via the Internet can be used
more easily if hypertext links are enabled using HTML
and URLs: it’s called World Wide Web
The ARPANET needs to convert to
a standard protocol and be renamed to
The Internet
We need a protocol for Efficient
and Reliable transmission of
Packets over a WAN: TCP/IP
Ideas from
1940s to 1969
1970
1995

11. The Creation of the Internet

The creation of the Internet solved the following challenges:
 Basically inventing digital networking as we know it
 Survivability of an infrastructure to send / receive high-speed
electronic messages
 Reliability of computer messaging

12. The Universal Resource Locator (URL)
Each page of information on the web has a unique address called the
URL at which it can be found
http://faculty.uscupstate.edu/atzacheva/lecture1.html
The document
can be obtained
using the
Hypertext
Transfer Protocol
(HTTP)
1
Protocol
Host Name The Name of
Web Server
2
Host Name
Path to the Web
Page
File Name
Denotes that the File
is Written in HTML
HyperText Markup
Language
3
File Name

13. Protocols that may appear in URL’s
Protocols Names
Use
ftp://
File transfer
http://
Hypertext
https://
Hypertext Secure
Mailto:
Sending email
News:
Requesting news
telnet://
Remote login
Much of the power of browsers is that they are multiprotocol.
That is, they can retrieve and render information from a variety of
servers and sources.

14. Web Client/Server Architecture

15. The Problem

Before Internet: different packet-switching networks
(e.g., ARPANET, ARPA packet radio)

only nodes on the same network could communicate

16. A Translation-based Solution
ALG
ALG
ALG

application-layer gateways





inevitable loss of some semantics
difficult to deploy new internet-wide applications
hard to diagnose and remedy end-to-end problems
stateful gateways inhibited dynamic routing around failures
no global addressability

ALG
ad-hoc, application-specific solutions

17. The Internetworking Problem

Two nodes communicating across a “network of
networks”…
 How to transport packets through this heterogeneous
mass ?
A
B
Cloud
Cloud
Cloud

18. Declared Goal

“…both economic and technical
considerations lead us to prefer that the
interface be as simple and reliable as
possible and deal primarily with passing data
between networks using different packet
switching strategies”
V. G. Cerf and R. E. Kahn, 1974

19. The Challenge: Heterogeneity


Share resources of different packet switching
networks  interconnect existing networks
… but, packet switching networks differ widely



different services
 e.g., degree of reliability
different interfaces
 e.g., length of the packet that can be transmitted, address
format
different protocols
 e.g., routing protocols

20. The Challenge: Scale

Allow universal interconnection


Mantra: Connectivity is its own reward
… but, core protocols had scalability issues




Routing algorithms were limited in the number of
nodes/links they could handle and were unstable after a
point
Universal addressing to go with routing
As large numbers of users are multiplexed on a shared
system, a congestion control paradigm is necessary for
stability
No universal, scalable naming system…

21. The Internetworking Problem


Problems: heterogeneity and scaling
Heterogeneity:



How to interconnect a large number of disparate
networks ? (lower layers)
How to support a wide variety of applications ?
(upper layers)
Scaling:

How to support a large number of end-nodes and
applications in this interconnected network ?

22. Solution
Network Layer
Gateways

23. The IP Solution …
IP
IP
IP




IP
internet-layer gateways & global addresses
simple, application-independent, lowest denominator
network service: best-effort datagrams
stateless gateways could easily route around failures
with application-specific knowledge out of gateways:
 NSPs no longer had monopoly on new services
 Internet: a platform for rapid, competitive innovation

24. Network-layer Overlay model

Define a new protocol (IP) and map all
applications/networks to IP
Require only one mapping (IP -> new protocol) when
a new protocol/app is added
 Global address space can be created for universal
addressibility and scaling


25. Before IP
(FTP – File Transfer Protocol, NFS – Network File Transfer, HTTP – World Wide Web protocol)
Application
Transmission
Media

Telnet
FTP
Coaxial
cable
NFS
Fiber
optic
HTTP
Packet
radio
No network level overlay: each new
application has to be re-implemented for
every network technology!

26. IP

Key ideas:


Overlay: better than anyany translation. Fewer, simpler
mappings.
Network-layer: efficient implementation, global addressing
Application
Telnet
FTP
NFS
HTTP
Intermediate
Layer (IP)
Transmission
Media
Coaxial
cable
Fiber
optic
Packet
radio

27. Original TCP/IP (Cerf & Kahn)


No separation between transport (TCP) and
network (IP) layers
One common header

use ports to multiplex multiple TCP connections
on the same host
32
Source/Port


32
Source/Port
16
16
8n
Window
ACK
Text
Byte-based sequence number (Why?)
Flow control, but not congestion control

28. Today’s TCP/IP

Separate transport (TCP) and network (IP)
layer (why?)



split the common header in: TCP and UDP
headers
fragmentation reassembly done by IP
Congestion control

29. Addressing

How to find if destination is in the same
network ?

IP address = network ID + host ID.


Source and destination network IDs match => same
network (I.e. direct connectivity)
Splitting address into multiple parts is called
hierarchical addressing
Network
Boundary
Host

30. Converting a 32-bit Internet Address to
Dotted Decimal Format
Recall binary to decimal conversion




An Internet address, known as an IP address for “Internet Protocol”
is comprised of four binary octets, making it a 32-bit address.
IP addresses, difficult for humans to read in binary format, are often
converted to “dotted decimal format”
To convert the 32-bit binary address to dotted decimal format, divide
the address into four 8-bit octets and then convert each octet to a
decimal number.
Each octet will have one of 256 values (0 through 255)
192.48.29.253
(Example of an IP address in dotted decimal form)

31. IP address conversion
Convert the following 32-bit Internet address into dotted decimal format:
01011110000101001100001111011100
1) Divide the IP address into four octets
01011110
00010100
11000011
11011100
2) Convert each binary octet into a decimal number
01011110 = 64+16+8+4+2 = 94
00010100 = 16+4 = 20
11000011 = 128+64+2+1 = 195
11011100 = 128+64+16+8+4 = 220
3) Write out the decimal values separated by periods
94.20.195.220

32. The Internet Network layer
Host, router network layer functions:
This image cannot currently be display ed.
Transport layer: TCP, UDP
Network
layer
IP protocol
•addressing conventions
•datagram format
•packet handling conventions
Routing protocols
•path selection
•RIP, OSPF, BGP
routing
table
ICMP protocol
•error reporting
•router “signaling”
Link layer
physical layer

33. IP Addressing: introduction



IP address: 32-bit identifier for
host, router interface
Interface: connection between
host, router and physical link
 router’s typically have
multiple interfaces
 host may have multiple
interfaces
 IP addresses associated with
interface, not host, router
Hosts in the same network have
same network ID
223.1.1.1
223.1.1.2
223.1.1.4
223.1.1.3
223.1.2.1
223.1.2.9
223.1.3.27
223.1.2.2
223.1.3.2
223.1.3.1
223.1.1.1 = 11011111 00000001 00000001 00000001
223
1
1
1

34. IP Address Classes



There are 5 different classes of IP addresses: A, B, C, D and E.
A, B, and C are available for commercial use
For example, a Class A network could support 126 networks,
each with 16,777,216 hosts

35. Subnet Addressing


Classful addressing inefficient: Everyone wants class B addresses
Can we split class A, B addresses spaces and accommodate more
networks ?
 Need another level of hierarchy. Defined by “subnet mask”,
which in general specifies the sets of bits belonging to the
network address and host address respectively
Network
Host
Boundary is flexible, and defined by subnet mask

36. The Domain Name System

We would go crazy if we would have to remember the IP
addresses of all the web sites that we wanted to visit

The Domain Name System translates between domain names
and IP addresses of devices connected to the Internet
– A domain name (a part of the URL) is a unique alphanumeric
name such as gmu.edu
– The top level domain name is edu and the secondary level
domain name is gmu in the above example (there could be
up to 127 levels, but more than 4 is rare)

37. Examples of top level domains

Generic top level domains
.com
 .biz
 .info
 .edu
 .mil
 .net, etc.
Country codes (2 character codes)
 .jp, .sw, .us, etc.



38. DNS
IP ADDRESSES
Every device connected
has a unique 32-bit
address
Machine Readable
e.g. 151.196.19.22
DOMAIN NAMES
DNS
Translation Between
domain Names and IP
Addresses
Human
Readable
cnn.com
Every device
connected has an
alphanumeric
address
 IP address and domain name allocation requires central administration to
avoid duplication
 Previously administered by U.S. government contract (NSI)
 In 1998, technical coordination assigned to ICANN (Internet Corporation for
Assigned Names and Numbers).