A network is group of two or more systems linked together.
Home Network Applications
Access to remote information
- Online Library, Newspaper
- Instant messaging, news group, torrent
- Live Channels, videos, Audios
- Home shopping, access to financial institutions
Types of Networks
1-Basis on Medium
There are two types of medium
a) Wired Network
- Using Twisted Pair Cable
- Using Coaxial Cable
- Using fiber optics
Advantages & Disadvantages:
Wired networks use Ethernet cables and network adapters.
It can difficult to run cables under the floor or through walls, especially when computers are in different rooms.
A wired doesn’t cost much because Ethernet cables, hubs and switches are inexpensive.
b) Wireless Network
- 1.Wifi (Wireless fidelity) 802.11 a/b/g/n
- 2.WiMax (Worldwide Interoperability for Microwave Access) 802.16e
Advantages & Disadvantages:
Wireless signals are subject to interference from other home appliances
Wi-Fi performance is distance sensitive
wireless communication signals travel through the air and can easily be intercepted.
2-Basis on Network Architecture
Computer networks may be classified according to the functional relationships which exist among the elements of the network
- 1.Centralized resources
- 2.Improved security
- 3.Server Level Administration
- 4.Scalable Network
- 1.Increased Cost
- 2.A Weak Link
- 1.No need for a network administrator
- 2.Network is fast/inexpensive to setup & maintain
- 3.Each PC can make backup copies of its data to other PCs for security.
- Easiest type of network to build, peer-to-peer is perfect for home.
- This network is not centralized, making administration difficult
- Lack of security
- No link in the network is reliable
- Useful for a small number of computers (generally about 10)
3-Basis of Scale/Area
4-Basis of Topologies:
All of the nodes of the network are connected to a common transmission medium which has exactly two end points
Each of the nodes of the network is connected to two other nodes in the network and with the first and last nodes being connected to each other, forming a ring
Each of the nodes of the network is connected to a central node with a point-to-point link
Each of the nodes of the network is connected to each of the other nodes in the network with a point-to-point link
5-Basis of Logical Topologies
Token Ring network uses a token passing technology. A computer with a message to deliver waits until it receives free token. The computer then changes the free token into a busy token, attaches its message to it, and retransmits it on the circuit to the next computer.
Standards Terminologies used for Token Ring
Token Ring-4: 4Mbps over twisted wire
Token Ring-16: 16Mbps over twisted wire
This is a system where each computer listens to the cable before sending anything through the network. If the network is clear, the computer will transmit. If some other node is already transmitting on the cable, the computer will wait and try again when the line is clear. Sometimes, two computers attempt to transmit at the same instant. When this happens a collision occurs. Each computer then backs off and waits a random amount of time before attempting to retransmit.
Standards Terminologies used for Ethernet
10Base5: 10Mbps baseband signal with 500 meter range
100Base2: 100Mbps baseband signal with 200 meter range
100BaseT: 100Mbps baseband signal with Twisted pair wire
100Broad36: 100Mbps broadband signal with 3600 meter range