Lmt_computer Network Types

8/14/2019 Lmt_computer Network Types

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as c actors nee ng

considering in Networking (data

Comm) The cost Clarity

Time response The message should reach safe secured

Should deliver to right person


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Ancient methods

Horse rider

Pigeons

Drum bitter


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Data communication


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Data types

Text

Number

Image Audio

vedio


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Data flow

Simplex

Half duplex

Full duplex


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Computer network

an interconnection of agroup of computers

A network is basically all ofthe components (hardware

and software) involved inconnecting computersacross small and largedistances. Networks areused to provide easyaccess to information, thusincreasing productivity forusers.


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Computer Network classification

By scale

By network topology

By connection method By functional relationship (Network

Architectures)

By protocol


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By Scale

Personal area network (PAN)

Local Area Network (LAN)

Campus Area Network (CAN) Metropolitan area network (MAN)

Wide area network (WAN)

Global Area Network (GAN)


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Personal Area Network (PAN)

A personal area network (PAN) is a computer networkused for communication among computer devices close to

one person. Some examples of devices that may be used in a PAN are

printers, fax machines, telephones, PDAs or scanners.

The reach of a PAN is typically within about 20-30 feet(approximately 4-6 Meters).

PANs can be used for communication among the individualdevices (intrapersonal communication), or for connecting toa higher level network and the Internet (an uplink).

Personal area networks may be wired with computer busessuch as USB.

A wireless personal area network (WPAN) can also bemade possible with network technologies such as IrDA andBluetooth.


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Advantages of a Networked OfficeUsing Microsoft Windows 95/98/ME/2000/XP

Software

Printers

Internet


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Local Area Network (LAN) A network covering a small geographic area, like a home, office,

or building.

much higher data transfer rates, smaller geographic range, andlack of a need for leased telecommunication lines.

Current LANs are most likely to be based on Ethernettechnology. For example, a library will have a wired or wirelessLAN for users to interconnect local devices (e.g., printers andservers) connect to the internet. All of the PCs in the library are

connected by category 5 (Cat5) cable, running the IEEE 802.3protocol through a system of interconnection devices andeventually connect to the internet.

The cables to the servers are on Cat 5e enhanced cable, whichwill support IEEE 802.3 at 1 Gbps.

All user computers can get to the Internet and the card catalog. Each workgroup can get to its local printer. Note that theprinters are not accessible from outside their workgroup.


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Advantages of a Networked OfficeUsing Microsoft Windows 2003

Domain Controller

1. Authentication2. Logging

3. Security

Centralizations

1. Dedicated File

Server

2. Redundancy

3. Disaster

Recovery

4. Virus Scanning


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Campus Area Network (CAN) A network that connects two or more

LANs but that is limited to a specific andcontiguous geographical area such as acollege campus, industrial complex, or a

military base. A CAN, may be considered a type of MAN

(metropolitan area network), but isgenerally limited to an area that is smaller

than a typical MAN.


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Metropolitan Area Network (MAN) A MAN is optimized for a larger geographical area than is a LAN, ranging

from several blocks of buildings to entire cities.

MANs can also depend on communications channels of moderate-to-high

data rates. A MAN might be owned and operated by a single organization, but it

usually will be used by many individuals and organizations.

MANs might also be owned and operated as public utilities.

They will often provide means for internetworking of local networks.

Metropolitan area networks can span up to 50km, devices used are modemand wire/cable.

A Metropolitan Area Network is a network that connects two or more LocalArea Networks or Campus Area Networks together but does not extendbeyond the boundaries of the immediate town, city, or metropolitan area.Multiple routers, switches & hubs are connected to create a MAN.

Some technologies used for this purpose are ATM, FDDI.

MAN links between LANs have been built without cables using eithermicrowave, radio, orinfra-red laserlinks.
http://en.wikipedia.org/wiki/Asynchronous_Transfer_Modehttp://en.wikipedia.org/wiki/FDDIhttp://en.wikipedia.org/wiki/Local_area_networkhttp://en.wikipedia.org/wiki/Microwavehttp://en.wikipedia.org/wiki/Radiohttp://en.wikipedia.org/wiki/Free-space_optical_communicationhttp://en.wikipedia.org/wiki/Free-space_optical_communicationhttp://en.wikipedia.org/wiki/Radiohttp://en.wikipedia.org/wiki/Microwavehttp://en.wikipedia.org/wiki/Local_area_networkhttp://en.wikipedia.org/wiki/FDDIhttp://en.wikipedia.org/wiki/Asynchronous_Transfer_Mode


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Wide Area Network (WAN)

A WAN is a data communications network thatcovers 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 astelephone companies.

WAN technologies generally function at the

lower three layers of the OSI reference model:

the physical layer, the data link layer, and the

network layer.


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Global Area Network (GAN)

Global area networks (GAN) specifications are indevelopment by several groups, and there is nocommon definition.

In general, however, a GAN is a model forsupporting mobile communications across anarbitrary number of wireless LANs, satellitecoverage areas, etc.

The key challenge in mobile communications is"handing off" the user communications from onelocal coverage area to the next


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Internetwork

Two or more networks or network

segments connected using devices that

operate at layer 3 (the 'network' layer) of

the OSI Basic Reference Model, such as arouter. Any interconnection among or

between public, private, commercial,

industrial, or governmental networks mayalso be defined as an internetwork.


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three variants of internetwork

Intranet

Extranet

"The" Internet


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Intranet

An intranet is a set of interconnected

networks, using the Internet Protocol anduses IP-based tools such as webbrowsers, that is under the control of asingle administrative entity. Thatadministrative entity closes the intranet tothe rest of the world, and allows onlyspecific users. Most commonly, an intranet

is the internal network of a company orother enterprise.


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extranet An extranet is a network or internetwork that is

limited in scope to a single organization or entitybut which also has limited connections to thenetworks of one or more other usually, but notnecessarily, trusted organizations or entities (e.g.

a company's customers may be given access tosome part of its intranet creating in this way anextranet, while at the same time the customersmay not be considered 'trusted' from a securitystandpoint). Technically, an extranet may also be

categorized as a CAN, MAN, WAN, or other typeof network, although, by definition, an extranetcannot consist of a single LAN; it must have atleast one connection with an external network.


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Internetwork

connecting two or more distinct

computer networks or network

segments together to form an

internetwork


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Topology based network types

Bus network

Star network

Ring network Mesh network

Star-bus network

Tree or Hierarchical topology network,etc.


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Bus Topology Linear Bus - The type of

network topology in which

all of the nodes of thenetwork are connected toa common transmissionmedium which hasexactly two endpoints.

Distributed bus - Thetype of network topologyin which all of the nodesof the network are

connected to a commontransmission mediumwhich has more than twoendpoints


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star topology A star topology is designed with

each node (file server, workstations,

and peripherals) connected directlyto a central network hub orconcentrator

All data that is transmitted betweennodes in the network is transmittedto this central node, which is usuallysome type of device that thenretransmits the data to some or allof the other nodes in the network,although the central node may alsobe a simple common connectionpoint without any active device torepeat the signals.


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Star topology

Extended star - A type of network topology in which anetwork that is based upon the physical star topologyhas one or more repeaters between the central node(the 'hub' of the star) and the peripheral or 'spoke' nodes,

the repeaters being used to extend the maximumtransmission distance of the point-to-point links betweenthe central node and the peripheral nodes beyond thatwhich is supported by the transmitter power of thecentral node or beyond that which is supported by the

standard upon which the physical layer of the physicalstar network is based.


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Star topology

Distributed Star -A type of network

topology that is composed of individual

networks that are based upon the physical

star topology connected together in alinear fashion (e.g., two or more 'stacked'

hubs, along with their associated star

connected nodes )


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Star topologyAdvantages of a Star Topology

Easy to install and wire. No disruptions to the network then connecting or

removing devices. Easy to detect faults and to remove parts.

Disadvantages of a Star Topology Requires more cable length than a linear topology. If the hub or concentrator fails, nodes attached are

disabled.

More expensive than linear bus topologiesbecause of the cost of the concentrators.

Ring topology


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Ring topology The type of network topology in which each

of the nodes of the network is connected to

two other nodes in the network and with thefirst and last nodes being connected to

each other, forming a ring all data that is

transmitted between nodes in the network

travels from one node to the next node in a

circular manner and the data generally

flows in a single direction only.

Each packet is sent around the ring until it

reaches its final destination. Today, the ring

topology is seldom used.

Ri t l


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Ring topology ..

Advantages

Very orderly network where every device has access to the tokenand the opportunity to transmit Performs better than a star topology under heavy network load Can create much larger network using Token Ring Does not require network server to manage the connectivity

between the computers

Disadvantages One malfunctioning workstation or bad port in the MAU can create

problems for the entire network Moves, adds and changes of devices can affect the network

Network adapter cards and MAU's are much more expensive thanEthernet cards and hubs Much slower than an Ethernet network under normal load


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Mesh Topology

The value of fully meshed

networks is proportional

to the exponent of the

number of subscribers,

assuming thatcommunicating groups of

any two endpoints, up to

and including all the

endpoints


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Tree

A tree topology combinescharacteristics of linear busand star topologies. Itconsists of groups of star-configured workstations

connected to a linear busbackbone cable .Treetopologies allow for theexpansion of an existingnetwork, and enable

schools to configure anetwork to meet theirneeds.


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Tree..

Advantages of a Tree Topology Point-to-point wiring for individual segments.

Supported by several hardware and softwarevenders.

Disadvantages of a Tree Topology Overall length of each segment is limited by the type

of cabling used.

If the backbone line breaks, the entire segment goesdown.

More difficult to configure and wire than othertopologies.

Hybrid network topologies


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Hybrid network topologiesThe hybrid topology is a type of network topology that is composedof one or more interconnections of two or more networks that arebased upon different physical topologies or a type of networktopology that is composed of one or more interconnections of two

or more networks that are based upon the same physical topology,but where the physical topology of the network resulting from suchan interconnection does not meet the definition of the originalphysical topology of the interconnected networks (e.g., the physicaltopology of a network that would result from an interconnection oftwo or more networks that are based upon the physical star

topology might create a hybrid topology which resembles a mixtureof the physical star and physical bus topologies or a mixture of thephysical star and the physical tree topologies, depending upon howthe individual networks are interconnected, while the physicaltopology of a network that would result from an interconnection oftwo or more networks that are based upon the physical distributed

bus network retains the topology of a physical distributed busnetwork).

St b


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Star-busA type of network topology in which the central nodes ofone or more individual networks that are based upon the

physical star topology are connected together using acommon 'bus' network whose physical topology is basedupon the physical linear bus topology, the endpoints ofthe common 'bus' being terminated with thecharacteristic impedance of the transmission medium

where required e.g., two or more hubs connected to acommon backbone with drop cables through the port onthe hub that is provided for that purpose (e.g., a properlyconfigured 'uplink' port) would comprise the physical busportion of the physical star-bus topology, while each of

the individual hubs, combined with the individual nodeswhich are connected to them, would comprise thephysical star portion of the physical star-bus topology.


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Star-of-stars

A type of network topology that is composed ofan interconnection of individual networks thatare based upon the physical star topologyconnected together in a hierarchical fashion to

form a more complex network e.g., a top levelcentral node which is the 'hub' of the top levelphysical star topology and to which other secondlevel central nodes are attached as the 'spoke'

nodes, each of which, in turn, may also becomethe central nodes of a third level physical startopology.


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Star-wired ring

A type of hybrid physical network topology that is acombination of the physical star topology and thephysical ring topology, the physical star portion of thetopology consisting of a network in which each of thenodes of which the network is composed are connected

to a central node with a point-to-point link in a 'hub' and'spoke' fashion, the central node being the 'hub' and thenodes that are attached to the central node being the'spokes' (e.g., a collection of point-to-point links from theperipheral nodes that converge at a central node) in afashion that is identical to the physical star topology,while the physical ring portion of the topology consists ofcircuitry within the central node which routes the signalson the network to each of the connected nodessequentially, in a circular fashion.


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Hybrid mesh

A type of hybrid physical network topologythat is a combination of the physicalpartially connected topology and one or

more other physical topologies the meshportion of the topology consisting ofredundant or alternate connectionsbetween some of the nodes in the network

the physical hybrid mesh topology iscommonly used in networks which requirea high degree of availability..


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functional based network types

Peer to peer

Client-server

3 tier Multi-tier

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