TELECOMMUNICATION

موضوع: TELECOMMUNICATION الأحد يونيو 20, 2010 6:28 am

Telecommunication

Introduction:-

Basic Communication Model
Source-
generates data to be transmitted
Transmitter-
Converts data into transmittable signals
Transmission System-
Carries data
- Receiver
Converts received signal into data
Destination-
Takes incoming data

Communications: Tasks

1-Transmission System Utilization
2-Interfacing
3-Signal Generation
4-Synchronization
5-Exchange Management
6-Error detection and correction
7-Addressing and routing
8-Recovery
9-Message formatting
10-Security
11-Network Management

Wide Area Network (WAN)
Large geographical area -
Crossing public rights of way-
- Rely in part on common carrier circuits
- Alternative technologies:-
Circuit switching
Packet switching
Frame relay
Asynchronous Transfer Mode (ATM)

Switching

* Circuit Switching
Dedicated communications path established for the duration of the conversation, e.g. telephone network
* Packet Switching
Data sent out of sequence
Small chunks (packets) of data at a time
Packets passed from node to node between source and destination
Used for terminal to computer and computer to computer communications

Local Area Network (LAN)
-Smaller scope
Building or small campus
Usually owned by same organization as attached devices-
Data rates much higher-
Usually broadcast systems-
Now some switched systems and ATM are being introduced-

Network ownership and service type
Private
Owned by individual or corporation-
-Restricted to owner’s use
-Typically used by large corporations
+ve
Complete control
-ve
Installation and operation costs
Public
-Owned by a common carrier
Individuals or corporations can subscribe-
Public refers to availability not data-
+ve
No need for staff to install/operate network
-ve
Dependency on carrier
Subscription fee
Network Management

Configuration Management -
to manage network resources(hardware, software, systems)

Fault Management-
to detect and overcome failures

Performance Management-
to measure the traffic *
* to maintain quality of service

Accounting Management-
to get the service usage data

Security Management-
to protect against fraud application

موضوع: رد: TELECOMMUNICATION الإثنين يونيو 21, 2010 2:24 am