IT 640 Modern Information Systems 1 IT 640 Modern Information Systems Dr Deepak B Phatak Subrao Nilekani Chair Professor Kanwal Rekhi School of Information Technology IIT Bombay Session 17, Networking Basics IT640-Session 17, Networking Basics Dr. Deepak B Phatak 2 SESSION OVERVIEW Internet Technologies Networking Basics Objectives LAN and WAN Introduction to Principles of Networking Layered Model IT640-Session 17, Networking Basics Dr. Deepak B Phatak 3 Internet Technologies Internet and Web Permits Access to Information That is Stored on Different Computers (Servers) Across the World This Accessibility Can be Incorporated as a Component of Information Systems IT640-Session 17, Networking Basics Dr. Deepak B Phatak 4 Networking Objectives Resource Sharing Distributed Data Bases Possible High Reliability As Good as a Single System Cost Effectiveness Affordable Information Systems Possible Scalability Number of Users, Number of Transactions IT640-Session 17, Networking Basics Dr. Deepak B Phatak 5 Scale of Networks 0.1 M Circuit Board 1 M Computer System 10 M Room 100 M Building 1 Km Campus 10 Km City 100 10000 Km Countries LAN WAN IT640-Session 17, Networking Basics Dr. Deepak B Phatak 6 Networking Basics Permit Exchange of Information Through Communication Between any Two Computer Systems on the Network Handling Information Broken into Smaller Chunks (Packets) by Sender, and Reassembled by Receiver
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IT 640 Modern Information Systems
1
IT 640 Modern Information Systems
Dr Deepak B PhatakSubrao Nilekani Chair Professor
Kanwal Rekhi School of Information TechnologyIIT Bombay
Session 17, Networking Basics
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 2
SESSION OVERVIEW
Internet TechnologiesNetworking Basics
ObjectivesLAN and WANIntroduction to Principles of NetworkingLayered Model
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 3
Internet Technologies
Internet and Web Permits Access to Information That is Stored on Different Computers (Servers) Across the WorldThis Accessibility Can be Incorporated as a Component of Information Systems
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 4
Networking Objectives
Resource SharingDistributed Data Bases Possible
High ReliabilityAs Good as a Single System
Cost EffectivenessAffordable Information Systems Possible
ScalabilityNumber of Users, Number of Transactions
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 5
Scale of Networks
0.1 M Circuit Board1 M Computer System10 M Room100 M Building1 Km Campus10 Km City100 10000 Km Countries
LAN
WAN
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 6
Networking Basics
Permit Exchange of InformationThrough Communication Between any Two Computer Systems on the NetworkHandling Information
Broken into Smaller Chunks (Packets) by Sender, and Reassembled by Receiver
IT 640 Modern Information Systems
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IT640-Session 17, Networking BasicsDr. Deepak B Phatak 7
Networking Basics
Handling CommunicationNetwork Must Ensure that All Packets of Information (Eventually) Reach the DestinationAddressing Mechanism Needed for NodesCommunication Protocol NeededInternational Standards Exist
IEEE 802.X
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 8
Networking Basics
Each Computer Node Must Have:Hardware to Connect to Network
Network Interface Card (NIC)
Software to CommunicateProtocol Suite (Such as TCP/IP)
Some Medium to Carry SignalsCables, Radio,
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 9
Network Types
Broadcast NetworksSingle Communication Channel Shared by Multiple MachinesPackets Sent by One System With a Destination AddressPacket Handled Only by Addressee, Ignored By Other Systems
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 10
Broadcast Networks
Packets Can be Addressed to ALL Systems
True Broadcast
Or Can Be Addressed To a Subset of Systems
Multicast
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Point to Point Networks
Consists of Many Connections Between Pairs of SystemsPackets Travel To Destination Across Several Systems
Multiple Routes May ExistSpecial Routing Mechanisms Required
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 12
Local Area Networks
Privately Owned NetworksWithin Buildings or CampusesWidely Used To Connect PCs to Departmental or Campus ServersBroadcast Technology Typical
Topology: Bus or Ring
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IT640-Session 17, Networking BasicsDr. Deepak B Phatak 13
Bus Topology
BUS
PC1 PC2 PC3 PCn
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Bus Topology
At Any Instant, Any One Machine TransmitsTransmission Control in Ethernet (IEEE 802.3) is Decentralized
If Packets Collide, Each Machine Re-Transmits After Random TimeTypically Works at 10 or 100 Mbps
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Ring Topology
PC1
PC2
PC3
PCn Token
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 16
Ring Topology
Packets Move around a RingTransmission Control Achieved Through Special MechanismIBM Token Ring (IEEE 802.5)
A Token is Passed Along RingToken Holder TransmitsOperates at 4 and 16 Mbps
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 17
Inter-Network
Multiple Networks Connected With Each OtherA Router Used To Forward Packets From One Node on one Network, Meant for a Node on Another NetworkRouter is Essentially a Packet Switching Node
Minimum One per LAN
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 18
Wide Area Networks
Router
Router
Router
Mumbai
Nagpur
Pune
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IT640-Session 17, Networking BasicsDr. Deepak B Phatak 19
Wide Area Networks
Inter-Network of LANs at Many Locations Through RoutersRouters Connected Through Point to Point Connections
Typically Through Leased or Dial-up Lines of PSTN / PSDN
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 20
The Layered Model
Network Software has to Perform a Number of Functions at a NodeLayering Permits Isolation of Functions
Each Layer Implements Some Services Through its Own Protocol SuiteService Can be Connection Oriented or Connectionless
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 21
The Layered Model
A Specific Layer at One End Talks to The Corresponding Layer at The Other EndWithin a Node, Interacts With other layers Above & BelowTwo Important Reference Models
ISO (OSI) and TCP
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IT640-Session 17, Networking BasicsDr. Deepak B Phatak 23
The ISO-OSI Reference Model
Physical medium
Transport
Network
Data-Link
Session
Presentation
Application
Transport
Network
Data-Link
Session
Presentation
Application
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 24
Physical Layer
Transmission of Raw BitsRecognition of 0 and 1Bit Rates Decided at This Layer
Media, Mechanical/Electrical Issues Typical Media is Copper
Twisted Pair, Coaxial Cable
Optical FiberVery Large Bandwidths (Gbps)Low Attenuation (30Km)
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IT640-Session 17, Networking BasicsDr. Deepak B Phatak 25
Data Link Layer
Main TaskTake The Raw Transmission Reception Facility and Ensure Error-Free CommunicationSend Data Frames, Receive & Process Acknowledge FramesControl Access To Shared Channel
As in Broadcast Mechanisms
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 26
Network Layer
Control The Operation of Routing of packets Across Networks. Address Resolution
Through Static TablesThrough Dynamic Tables
Handle Network CongestionUsage Accounting
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Transport Layer
Take The Message From Higher Layer And Convert Into Smaller Units (Packets). Reassemble in The Right SequenceEstablish Distinct Network Service for Each Transport ConnectionTrue End-to-End Layer
IT640-Session 17, Networking BasicsDr. Deepak B Phatak 28
Session And Presentation Layers
Establishing Sessions, to provide Dialog Services, SynchronizationResolve Common Presentation Issues
Text Coding ASCII, EBCDIC
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