Chapter 1 Introduction to Computer Networks and Data

advertisement
Chapter 1
Introduction to Computer
Networks and Data
Communications
Communication
The transmission of a signal by way of a
medium from sender to receiver
Sender
Signal
Receiver
Transmission
medium
2
Communication Problems
 Completeness & comprehension
 Attenuation & noises
 Competing resources
 Routing & addressing
 Security
3
Networks
 Computer network
 Voice network
 Data network
 Local area network
 Metropolitan area network
 Wide area network
 Personal area network
 Network management
4
Data Communications
 Data Communications:
 The movement of computer information (data)
from one point to another by means of electrical
or optical transmission systems
 Is a sub-field of telecommunications
 Telecommunications:
 Includes the transmission of voice and video as
well as data
5
Network Configurations
 Microcomputer-to-local area network
 Microcomputer-to-Internet
 Local area network-to-local area network
 Personal area network-to-workstation
 Local area network-to-metropolitan area network
 Local area network-to-wide area network
 Wide area network-to-wide area network
 Sensor-to-local area network
 Satellite and microwave
 Cell phones
 Terminal/microcomputer-to-mainframe computer
6
Convergence
 An Additional Basic Connection – telephone-
to-network



Telephone systems are ubiquitous and now carry
more data than voice
Common configuration – telephone connected to
POTS
Newer configuration (VoIP) – telephone-to-LAN
via gateway or telephone to gateway via
DSL/cable
7
Network Components
 Hardware
 Computer
 Network Interface Card (NIC)
 Hub
 Switch
 Bridge
 Router
 Software
 Network protocols
8
Network Architectures
 A reference model that describes the layers of
hardware and software necessary to transmit data
between two points or for multiple devices /
applications to interoperate
 Reference models are necessary to increase
likelihood that different components from different
manufacturers will converse
 Two models to learn: OSI model and TCP/IP
protocol suite
9
The OSI Model
Application
(7) User input to host
Presentation
(6) Data coding, formatting
Session
(5) Begin, frames, end, rules
Transport
(4) End-to-end delivery
Network
(3) Message routing
Datalink
(2) Frame formatting, error
Physical
(1) Physical connections
10
OSI vs. The Internet
Application
Application
Application
Transport
Transport
Transport
Network
Network
Network
Presentation
Session
Datalink
Physical
Interface
Network Access
Physical
11
Logical vs. Physical Connection
Application
Application
Presentation
Presentation
Session
Session
Transport
Transport
Network
Network
Datalink
Datalink
Physical
Physical
12
13
Download