Download - Types of computer networks
TYPES OF COMPUTER NETWORKS
Tatheer FatimaBS English (Sec 1-A)
COMPUTER NETWORKS
A network consists of two or more computers that are linked in order to share resources, exchange files, or allow electronic communications.
The computers on a network maybe linked through cables, telephone lines, radiowaves, satellites or infrared light beams
NEEDS OF COMPUTER NETWORK:
File sharing Resource sharing Communication and collaboration Remote access Data protection
TYPES OF NETWORKS:
Networks can be divided on the basis of: Geographical Area Network (LAN,MAN,WAN) Connection method (Wired or Wireless Networks) Functionality (client/server, peer to peer, hybrid networks) Topology (bus, star, ring and mesh) Protocol (TCP/IP, IPX/SPX, AppleTalk)
DEVICES USED TO CONNECT NETWORK
Routers Gateways Repeaters Bridges Hub Modems
GEOGRAPHICAL AREA NETWORK:
Local Area Network: LAN is a group of computers and associated devices that share a common
communications line or wireless link. Typically connected devices share the resources of a single processor or server
within a small geographic area. A local area network may serve as few as two or three users or as many as
thousands of users. Examples include twisted pair
GEOGRAPHICAL AREA NETWORK:
Metropolitan Area Network: MAN is a network that interconnects users with computer
resources in a geographic area or region larger than that covered by even a large LAN but smaller than the area covered by WAN
It is also used to mean the interconnection of several LANs by bridging them with backbone lines.
Examples include twisted pair and fibre-optic cables
GEOGRAPHICAL AREA NETWORK:
Wireless Area Network: WAN is a communications network that makes use of existing
technology to connect local computer networks into a larger working networks that may cover both national and international locations.
Examples include fibre-optics, radiowaves and satellites.
DIFFERENTIATION OF GEOGRAPHICAL AREA
CRITERIA LAN MAN WANOWNERSHIP OF NETWORK
private private or public Private or public
DESIGN AND MAINTAINANCE
Easy Not Easy Not Easy
COST Low High HigherNETWORK SIZE Small Larger LargestSPEED Fastest Slower SlowestTRANSMISSION MEDIA
Twisted Pair Twisted Pair and fibre-optic cables
Fibre-optics , radiowaves and satellite
NUMBER OF COMPUTERS
Smallest Large Largest
CONNECTION METHOD:
On the basis of connection method the network is classified into following 2 classes: Wired transmission networks Wireless transmission networks
WIRED TRANSMISSION:
Wired transmission of networks is a category of networks in which wiring is used as a medium for transmission of data
Wired networks use many types of wires described below:Twisted pair and coaxial cables: These type of wires are made up of copper. Transmit data in the form of electric pulses. Data transformation is not very fast and is also not secure.Fibre-optic cables: These type of wires are made up of plastic and glass. Transmit data in the form of light. Data transformation is very fast and speedy and is a very secure type of transformation.
WIRELESS TRANSMISSION:
In wireless transmission data transmission doesn’t require a specific medium rather air is used as a medium to transmit data.
Different frequency waves are used in wireless transmission networks.
Radiowaves: Transmit data ranging between 3kHz- 1GHzMicrowaves: Transmit data ranging between 3GHz- 300GHzRadiowaves: Transmit data ranging between 300GHz- 400THz
FUNCTIONALITY:
Networks are divided into 3 following categories on the basis of functionality: Client/Server networks Peer to peer networks Hybrid networks
DIFFERENTIATION B/T CLIENT/SERVER AND PEER TO PEER
Client/Server Peer -To-Peer
Server has to control ability while client’s don’t.
All computers have equal ability.
Higher cabling cost Cheaper cabling cost Used in small and large
networks Normally used in small networks
with less than 10 computers Easy to manage Hard to manage Install software only in the
server while the clients share the software
Install software to every computer
One powerful computer acting as server
No server is needed
HYBRID NETWORKS:
Hybrid networks are the networks that are based on both peer-to-peer & client-server relationship.
Hybrid networks incorporate the best features of workgroups in peer-to-peer networks with the performance, security and reliability of server-based networks.
Hybrid networks still provide all of the centralized services of servers, but they also allow users to share and manage their own resources within the workgroup.
Users can assign local access to resources in their computers. Workgroups can manage resources without requiring assistance from network
administrator Users may need to remember multiple passwords. Files saved on the workstation are not backed up.
TOPOLOGY:
Topology defines the arrangement of nodes, cables and connectivity devices that make up the network. There are 2 basic categories of topology: Logical topology: It describes the logical pathway a signal follows as it
passes among the network nodes Physical topology: It describes the actual layout of the network
transmission media i.e. how the transmission media is wired together. Common Physical topologies include:
Bus topology Star topology Ring topology Mesh topology
BUS TOPOLOGY:
Definition All computers and
devices are connected to a central cable.
Advantage Easy to connect a
computer or peripheral to a linear bus Requires less cable length than a star topology.
Disadvantage Entire network
shuts down if there is a break in the main cable. Terminators are required at the both ends of the backbone cable.
Difficult to identify the problem if the entire network shuts down.
STAR TOPOLOGY:
Definition All devices are
connected to a central device called hub.
Advantage Easy to install and
wire.
Disadvantage Requires more
cable length than a linear topology
Security can be implemented in the hub/switch. If the hub or
concentrator fails, nodes attached are disabled.
More expensive than linear bus topologies because of cause of concentrators.
Easy to detect faults and to remove parts.
MESH TOPOLOGY:
Advantage Provide redundant
path between device.
Disadvantage Requires more
cable than other topologies. The network can be
expanded without disruption to current user.
Has complicated implementations.
Definition In the mesh
topology each computer is connected to the others by separate cable.
RING TOPOLOGY:
Definition Cables forms
closed rings or loop, with all computers and devices arranged along ring.
Advantage Data is easily
transferred without a “bottleneck”.
Disadvantage Data packets must
pass through every computer between the sender & receiver which makes it a slow process.
The transmission of data is relatively simple as packets travel in one direction only.
If any of the nodes fail then the ring is broken n data transmission stops.
It is difficult to troubleshoot the ring.
PROTOCOL:
Protocol is a set of rules for the exchange of data between a terminal and a computer or between two computers.
Without protocol computers maybe connected but communication is not possible
Protocol is a sort of precommunication agreement about the form in which a message or data is to be sent and received.
The highlighted protocols include:1. TCP/IP protocol suite2. IPX/SPX protocol suite3. Apple talk
TCP/IP PROTOCOL SUITE
TCP/IP protocol suite was first defined in 1974. IP stands for internet protocol. It is a network layer protocol that is
responsible for delivering packets to network devices. TCP stands for transmission control protocol.it ensures a sent
message is sent without any loss of data or any mix up of the order of the data.
SPX/IPX PROTOCOL:
IPX/SPX is a routable protocol and can be used for small and large networks. It was created by Novell primarily for Novell NetWare networks, but is popular enough that it is used on products that are not from Novell SPX - Sequenced Packet Exchange operates at the transport layer
providing connection oriented communication on top of IPX. IPX - Internetwork Packet Exchange supports the transport and
network layers of the OSI network model. Provides for network addressing and routing. It provides fast, unreliable, communication with network nodes using a connection less datagram service.
APPLE TALK:
AppleTalk was a proprietary suite of networking protocols developed by Apple Inc. for their Macintosh computers.
Apple Computer developed the AppleTalk protocol suite to implement file transfer, printer sharing, and mail service among Apple systems only.
It is secure than other protocols
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