Definition

-A numbers of computers connected together for the purposes of communication

Advantages of computer network

-Networks enable multiple users to share resources (devics and data)
-Saves money
-Saves time
-Network allow you to edit and manage resources on multiple computers from a central

Disadvantages of computer network

-Network Hardware ,Software and Setup Costs
-Hardware and Software Management and Administration Costs
-Undesirable Sharing
-Illegal or Undesirable Behaviour
-Data Security Concerns

Client

-A computer on the network that request resources or services from another computer on a network

Server

-A computer on the network that manages shared resources

Workstation

-A personal computer that (ex: desktop or laptop), which may or may not be connected to a network; most clients are workstation computers

Network Interface Card

-The device inside a computer that connects a computer t othe network media

Network Operating System

-The software that runs on a server and enables the server t omanage data, users, groups, security, applications, and other networking functions

Host

-A computer that enables resource sharing by other computers on the same network

Node

-A client, server, or other device that can communicate over a network and that identified by a unique number, known as its network address

Connectivity

-A specialized device that allow multiple parts of one network to connect and exchange data

Backbone

-The part of a network to which segments and significant shared
devices (such as routers, switches, and servers) connect.

Topology

-The physical layout of a computer network. Topologies vary according to the needs of the organization and available hardware and expertise.

Protocol

• A format for communication between networked devices

Transmission Media

-The means through which data are transmitted
and received.

Advantages

-Easy to set up
-Less complexity
-Lower cost since network devices and dedicated servers may not be requires
-Can be use for simple tasks such as transferring files and sharing pronters

Disadvantages

-No centralized administration
-Not as secure
-Not scalable
-All devices may acts as both clients and servers which can slow their performance

Client/Server Networks

-Another way of designing a network is to use a central computer,known as a server; to facilitate communication and resource sharingbetween other computers on the network, which are known as clients.
-A network that uses a server to enable clients to share data, data storage space, and devices is known as a client/server network.
-A client/server architecture is sometimes used to refer to the design of a network in which clients rely on servers for resource sharing and processing.

Network of many sizes

-small home networks
-small office/home office network
-medium to large networks
-world wide networks

type of networks

-Local area network (LAN)
-wide area network (WAN)
-Metropolitan Area Network (MAN)
-Wireless LAN (WLAN)
-Storage Area Network (SAN)
-Personal Area Network (PAN

The internet

-Internet is connecting a computer to any other computer anywhere in the world via dedicated routers and servers. When two computers are connected over the Internet, they can send and receive all kinds of information such as text, graphics, voice, video, and computer programs.

Difference between extranet and internet

Extranet-shared content accessed by groups through cross-enterprise boundaries
Internet-shared content accessed by members within a single organization

Fault tolorance

-The expectation is that the Internet is always available to the millions of users who rely on it. This requires a network
architecture that is built to be fault tolerant. A fault-tolerant network is one that limits the effect of a failure, so that the
fewest number of devices are affected by it. It is also built in a way that enables quick recovery when such a failure occurs.
Fault-tolerant networks depend on multiple paths between the source and destination of a message. If one path fails, the
messages can be instantly sent over a different link. Having multiple paths to a destination is known as redundancy

Scalability

-Thousands of new users and service providers connect to the
Internet each week. In order for the Internet to support this rapid amount of growth, it must be scalable.
A scalable network can expand quickly to support new users and applications without affecting the performance of the
service being delivered to existing users.

Quality of Service

internetworks, such as voice and live video transmissions -Quality of service is also an ever-increasing requirement of
networks today. New applications available to users over

Security

-Securing a network infrastructure includes physically securing
devices that provide network connectivity, and preventing unauthorized access to the management software that resides
on those devices.