Transcript CSCI 4550/8556 Computer Networks

CSCI 4550/8556
Computer Networks
Comer, Chapter 1:
Introduction
How do computer networks and
internets operate?
Network: a system for connecting computers using a single
transmission technology
Internet: a set of networks connected by routers that are
configured to pass traffic among any computers attached to
networks in the set
Data transmission - network media and data encoding
Packet transmission – data exchange over a network
Internetworking – universal service over a collection of
networks
Network applications – programs that use an internet
Explosive Growth
New phenomenon - now, networks are an
important part of everyday activities:
Business
Home
Government
Education
The global Internet is growing exponentially:
Initially, a research project with a few dozen sites
Today, millions of computers and thousands of networks
world-wide
Internet
Has its roots in the military network called Arpanet
Fundamental changes from centralized to distributed computing
Incorporated features for reliability and robustness
• Multiple links
• Distributed routing
Ethernet made local networking feasible
TCP/IP protocol made internetworking possible
Developed after Arpanet
Switchover occurred in 1983
Exponential growth - doubling every 18 months
Economic Impact
A large industry has grown around:
Networking hardware
Computers
Software
Companies must integrate the planning,
implementation, management and upgrade of their
networks
Complexity
Computer networking is complex:
Many different hardware technologies
Many different software technologies
All can be interconnected in an internet
No underlying theory
Terminology can be confusing
TLAs
Industry redefines or changes terminology from
academia
New terms invented all the time
Abstractions and Concepts
We will concentrate on abstractions and concepts
to unravel complexity
Examples:
The types of LAN wiring, rather than the details of LAN
data transmission
The definition and concept of congestion, rather than
specific congestion control mechanisms
On-line Resources
Glossary search
Textbook table of contents
Textbook index
Website materials