Computer netwoks meaning, types, benefits

Computer Networks- Structure and TypesConnecting Devices

BYDr. SAJEEVE V.P.

04/11/2023 1Dr.SAJEEVE VP

Network- meaning

Linking of two or more computerswith or without wiresso as to provide access- mutual or one way


Network – types-

1. Based on structure-Star, Bus, Ring, Mesh2. Based on Area- WAN, LAN, MAN3. Based on status- Client-Server, Peer-Peer4. Based on Purpose- Storage Area

Network, others


1. Network – types- Based on Structures or Topologygeometrical arrangement of devices, nodes and links,

Nodes –end point-ws, terminal, equipment, etc

Link-the comn.path- circuit, channel1. Star Network2. Bus Network3. Ring Network4. Mesh Network


1. STAR NETWORK

One computer at the centreOthers around it. +Saves cableFault in one node

-other nodes unaffected-No connection between nodesNode needs to connect through cental


STAR NETWORK- evaluation

Merits Nodes easily added / removedFault in one node, other nodes unaffectedEasier to diagnose node failures.

Demerits:If central hub fails, entire system collapsesNo connection between nodesNode needs to connect through cental


2. Bus network

Nodes connected in a serial To a single main (backbone) cable


Bus network- evaluation

Merits Saves cable, less costly To a single main (backbone) cableEasy extension

Demerits:Heavy traffic jam the networkEvery adnl. connection weakens the

systemDifficult to diagnose node failures


3.Ring network

Nodes connected in a circular cable


3.Ring network- evaluation

Merits Good for small net worksSpan longer distance

Demrits ExpensiveDifficult to diagnse failureRevision interupts network.Expansion difficult


4.Mesh network

Main ring line connectes every nodeBesides nodes are connected mutually


4.Mesh network

Merits Good large organisationsIf main line fails, nodes continue to workLess traffic jam

Demrits Most expensiveDifficult to diagnse failureRevision interupts network


Network – what for? -USES

1.Sharing of resources Processor speed Storage Hardwares

-Peripherals connected-printer, scanner, camera, microphone, speakers, projector

-Softare-Internet services

2. Savings in cost / resources/ installation04/11/2023 13Dr.SAJEEVE VP

Network – what for

3. Quick, real-time two-way communication

Information / data transfer Banking, fund transfer, email.

4. Easy and quick access to files5. Personal touch-

video call and conference6. Leads to efficiency-prompt employees to

report to, work in time.7. Distributed processing8. Less supervision-system auto-checks


Network – risks

1. Failure of one unit in the network collapses the entire system

2. Too much sophistication makes difficult to manage and operate without experts

3. Data loss affects the entire system, especially if no proper backup.

4. Cost 5. Nodes not independent- permission


2. Network – Types Based on area

LAN- Local Area Network MAN- Metropolitan (medium) Area Net Work WAN – Wide Area Network


LAN- Local Area Network

Network of computers in restricted (small) limited geographical

area.

Whole network confines to single site.Within an office, one organisation, campus.


LAN- Components

File servers Network operating system (software) PC, W. Stns, nodes-(computers) Network interface cards Cabling / wireless connectivity


3. Network types- Based on status-Network Architecture-

organisation of networksClient – server (main-sub)

one main computer serving the nodesseveral nodes needing permission to access

Peer-to peer (equal status)All computers are of same statushaving equal access to any other.no permission needed


LAN-WAN Comparison

WAN

1. Wider area2. Aim- Communication3. External comunication

link4. Hired services from third

party- ISP

5. Interruption frequent

6. Data error chance more7. More devices required7. May link several LANs

LAN

1. Small area2. Aim-resource sharing3. Only internal cables4. Owned 5. Little interruption

6. Small chance7. Less devices8. May be linked to WAN


What decides LAN-WAN ?

1. 3 computers / 100 computers2. WAN needs to have many LANS

3. One computer in India connected to another in the USA- WAN OR LAN?

4. Two computers in the same lab connected through internet.


4. Network – types- Based on Purpose

A. Storage Area Network (SAN)centrally managed storage1. Network Attached Storage (NAS)

A dedicated shared storage File servers-large capacity to storePermit nodes to share

2. Direct Attached Storage (DAS)Storage attached to a single server.


5. Other Network – types- Based on Purpose

Based on mode of connectionWireless and wiredGlobal and national

Information super Highwayglobal networkingall digitally deliverable services.


Network devices1. Network Interface Card2. Front end processor specialise in extnl.

com3. Multiplexer-routing multiple requests.4. MODEM- wifi5. Communication Channels-Cables/

Cell/tower/Satellite

6. Remote access devices1. Hub- connecting link for LANs2. Bridge, 3. Repeater- strenthen- link if obstacles4. Router –processor-MAC addresses in NICs5. Switches-many ports- IP address


HUB

1. A hardware device (include no s/w)2. Common linking point3. Usually connects two or more LANs4. Does not read addresses but 5. Simply passes data without screening6. Flooding- sending all to all nodes other

than sender- so more jam.7. Junction point for LANs 8. Usually used in a campus to connect to

LANs in several depts.04/11/2023 25Dr.SAJEEVE VP

Gateways

1. A hardware device (include no s/w)2. Entrance to a network3. Usually connects two or more LANs4. Does not read addresses but 5. Simply passes data without screening6. Flooding- sending all to all nodes other

than sender- so more jam.7. No data management capacity unlike

routers or switches04/11/2023 26Dr.SAJEEVE VP

Bridge

1. Connects two n/w (LANs or WANs) 2. Reads the destination address 3. Sends the data only to the addressee4. So less jam5. Screens by destination address6. No flooding-7. Junction point for LANs 8. Usually used in different n/ws


Router

1. Connects two or more n/ws 2. Of different protocols3. Programmable computer4. Reads the destination by MAC address 5. Sends the data only to the addressee6. No flooding-less jam7. Reads data inside the packets8. So programmable 9. Allow or not access certain data

video/aud.04/11/2023 28Dr.SAJEEVE VP

Switch

1. Connects two or more n/ws 2. Of different protocols3. Many ports4. Programmable computer5. Reads the destination by MAC address 6. Sends the data only to the addressee7. No flooding-less jam8. Reads data inside the packets9. So programmable 10. Allow or not- access certain data video/aud.


differences

Respect HUB Gtwys BridgeRutrSwitch

Read address N Desti Y Y Ydifferent protocolsN N N Y YMany ports N N N N YProgrammable compu N N N Y YReads MAC address N N N Y YIP ADDRESS N N N N YAddressee ONLY N N Y Y YFooding / jam Y Y N N NRead inside packets N N N Y YProgrammable N N N Y YData screening. N N N Y Y


Computer netwoks meaning, types, benefits

Technology

Transcript of Computer netwoks meaning, types, benefits