Ch 2 CS Class 11
Important Easy Notes of Computer Science of Information Networks Ch 2 CS Class 11 written by Professor Mr. Syed Werasat Hussain Hashmi Suib. These notes are very helpful in the preparation of Computer Science for students of the 11th class and these are according to the paper patterns of all Sindh Book Boards.
Summary and Contents:
Topics which are discussed in the notes are given below:
- What is computer network
- Types of Networks (On the Basis of Scale)
- Describe Local area network (LAN)
- Describe Campus Area Network
- Describe Metropolitan Area Network
- Describe Wide Area Network: A WAN is a data communications network that covers a relatively broad geographic area (i.e. one
city to another and one country to another country) and that often uses transmission facilities provided by
common carriers, such as telephone companies.
- Types of Networks: (On the Basis of Functional Relationship)
- Server Based Systems: Advantages Strong central security
Ability to share expensive equipment, such as laser printers.
Freeing of users from the task of managing the sharing of recourses.
Easy manageability of a large member of users.
Central organization, which keeps data from gently last among computers.
- Disadvantages:
Expensive dedicated hardware.
Expensive network operating system software and client licenses.
A dedicated network administrator (usually required).
- Types of Networks (On the Basis of Topology): The physical layout or shape of the network is called topology Networks can be laid into the five
basic topologies:
Star
Ring
Bus
Hybrid
FDDI.
- Definition of Star Networks with examples.
- Advantage:
If the connection is broken between any communications device and the hub, the rest of the
devices will continue operating.
New terminals can be added to a network easily.
There is no chance of data collision because central server prevents collisions between messages.
If a connection is broken between any communications device and the central server, the rest of
the devices on the network will continue operating.
Transmission delays between two terminals of between server and terminal do not increase by
adding new nodes to the network because any two devices may be connected via two links only
- Disadvantage:
Hub is the central point of failure.
The network crucially depends on the central server. If the central server fails, the entire network
will stop.
Star topology is expensive because a separate cable is required for connecting each computer
with the central server.
- Describe and explain Bus Network with examples and Advantages and Disadvantages.
- Describe Hybrid Network with example
- Describe FDDI Network with example with examples and Advantages and Disadvantages.
- Describe Network Connectivity Devices
- To expand a single network without connecting it to other network, we can usually use one of the
following Network connectivity devices:
Hubs
Active Hubs
Passive Hubs
Repeaters
Bridges
- Describe Hubs
- Describe Passive Hubs
- Describe Active Hubs
- Describe Repeaters Hubs
- Describe Bridges
- Describe Internetwork Connectivity
- Describe Routers
- Describe Gateways
- Describe CSUs/DSUs
- Advantages of Networks
- Describe Sharing of Peripheral Devices
- Describe Sharing of Programs and Data
- Describe Better Communications
- Describe Security of Information
- Describe Access to Database
- Describe Major Features of Internet
- Advantages of Internet: Electronic Mail, Chats & Forms, E – Shopping & E – Business, Education, Information Retrieval, On-Demand Movies & Television, Customer Support, Access to Remote Computing, Bulk File Transfer, Social Video Gaming, News & Weather, Conferencing, Electronic Mail, Advantages of E-mail, Disadvantages of E-mail, Usenet, Telnet, File Transfer Protocol (FTP), Chat , Other Types of Chat, 3-D Virtual Chat, Instant Messaging, World Wide Web (WWW) and Addresses for World Wide Pages.
- Web Terminology: Anchor, Browser, Client, Domain Name, Extranet, Firewall, Frame, Home Page, HTML, Image Map, Intranet, Link, Proxy Server, Table, Web Site and Webmaster.
- Abuses of Internet: E-mail, News Groups, Web Browsing, Chat Programs and Conclusion.