IT 640 Modern Information
                                           Systems
                                             ...
IT 640 Modern Information
                                        Systems
  Networking Basics                             ...
IT 640 Modern Information
                                              Systems
  Bus Topology                            ...
IT 640 Modern Information
                                        Systems
  Wide Area Networks                            ...
IT 640 Modern Information
                                        Systems
  Data Link Layer                               ...
IT 640 Modern Information
                                            Systems
  TCP-IP Reference Model                    ...
IT 640 Modern Information
                                                  Systems
  The IP Datagram Header              ...
IT 640 Modern Information
                                        Systems
  APPLICATION LAYER                             ...
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Microsoft PowerPoint - it640-session17-networking basics-2005

  1. 1. IT 640 Modern Information Systems SESSION OVERVIEW IT 640 Modern Information Systems Internet Technologies Networking Basics Dr Deepak B Phatak Objectives Subrao Nilekani Chair Professor LAN and WAN Kanwal Rekhi School of Information Technology Introduction to Principles of Networking IIT Bombay Layered Model Session 17, Networking Basics Dr. Deepak B Phatak IT640-Session 17, Networking Basics 2 Internet Technologies Networking Objectives Internet and Web Permits Access to Resource Sharing Information That is Stored on Different Distributed Data Bases Possible Computers (Servers) Across the World High Reliability This Accessibility Can be Incorporated as As Good as a Single System a Component of Information Systems Cost Effectiveness Affordable Information Systems Possible Scalability Number of Users, Number of Transactions Dr. Deepak B Phatak IT640-Session 17, Networking Basics 3 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 4 Scale of Networks Networking Basics 0.1 M Circuit Board Permit Exchange of Information 1M Computer System Through Communication Between any 10 M Room LAN Two Computer Systems on the Network 100 M Building Handling Information 1 Km Campus Broken into Smaller Chunks (Packets) by 10 Km City Sender, and Reassembled by Receiver WAN 100 10000 Km Countries Dr. Deepak B Phatak IT640-Session 17, Networking Basics 5 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 6 1
  2. 2. IT 640 Modern Information Systems Networking Basics Networking Basics Handling Communication Each Computer Node Must Have: Network Must Ensure that All Packets of Hardware to Connect to Network Information (Eventually) Reach the Network Interface Card (NIC) Destination Addressing Mechanism Needed for Nodes Software to Communicate Communication Protocol Needed Protocol Suite (Such as TCP/IP) International Standards Exist Some Medium to Carry Signals IEEE 802.X Cables, Radio, Dr. Deepak B Phatak IT640-Session 17, Networking Basics 7 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 8 Network Types Broadcast Networks Broadcast Networks Packets Can be Addressed to ALL Single Communication Channel Shared Systems by Multiple Machines True Broadcast Packets Sent by One System With a Or Can Be Addressed To a Subset of Destination Address Systems Packet Handled Only by Addressee, Multicast Ignored By Other Systems Dr. Deepak B Phatak IT640-Session 17, Networking Basics 9 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 10 Point to Point Networks Local Area Networks Consists of Many Connections Between Privately Owned Networks Pairs of Systems Within Buildings or Campuses Packets Travel To Destination Across Widely Used To Connect PCs to Several Systems Departmental or Campus Servers Multiple Routes May Exist Broadcast Technology Typical Special Routing Mechanisms Required Topology: Bus or Ring Dr. Deepak B Phatak IT640-Session 17, Networking Basics 11 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 12 2
  3. 3. IT 640 Modern Information Systems Bus Topology Bus Topology At Any Instant, Any One Machine Transmits PC1 PC2 PC3 PCn Transmission Control in Ethernet (IEEE 802.3) is Decentralized If Packets Collide, Each Machine Re- BUS Transmits After Random Time Typically Works at 10 or 100 Mbps Dr. Deepak B Phatak IT640-Session 17, Networking Basics 13 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 14 Ring Topology Ring Topology Packets Move around a Ring PC1 Transmission Control Achieved Through Special Mechanism IBM Token Ring (IEEE 802.5) PCn PC2 Token A Token is Passed Along Ring Token Holder Transmits Operates at 4 and 16 Mbps PC3 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 15 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 16 Inter-Network Wide Area Networks Multiple Networks Connected With Each Router Other Mumbai A Router Used To Forward Packets From Router One Node on one Network, Meant for a Node on Another Network Nagpur Router is Essentially a Packet Switching Router Node Pune Minimum One per LAN Dr. Deepak B Phatak IT640-Session 17, Networking Basics 17 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 18 3
  4. 4. IT 640 Modern Information Systems Wide Area Networks The Layered Model Inter-Network of LANs at Many Locations Network Software has to Perform a Through Routers Number of Functions at a Node Layering Permits Isolation of Functions Routers Connected Through Point to Point Each Layer Implements Some Services Connections Through its Own Protocol Suite Typically Through Leased or Dial-up Lines of Service Can be Connection Oriented or PSTN / PSDN Connectionless Dr. Deepak B Phatak IT640-Session 17, Networking Basics 19 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 20 Open System Interconnect (OSI The Layered Model Model) A Specific Layer at One End Talks to The Corresponding Layer at The Other End Seven Layer Model Application Within a Node, Interacts With other layers Presentation Above & Below Session Two Important Reference Models Transport ISO (OSI) and TCP Network Data Link Physical Dr. Deepak B Phatak IT640-Session 17, Networking Basics 21 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 22 The ISO-OSI Reference Model Physical Layer Application Application Transmission of Raw Bits Presentation Presentation Recognition of 0 and 1 Session Bit Rates Decided at This Layer Session Media, Mechanical/Electrical Issues Transport Transport Typical Media is Copper Network Network Twisted Pair, Coaxial Cable Data-Link Data-Link Optical Fiber Very Large Bandwidths (Gbps) Physical medium Low Attenuation (30Km) Dr. Deepak B Phatak IT640-Session 17, Networking Basics 23 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 24 4
  5. 5. IT 640 Modern Information Systems Data Link Layer Network Layer Main Task Control The Operation of Routing of Take The Raw Transmission Reception packets Across Networks. Facility and Ensure Error-Free Communication Address Resolution Send Data Frames, Receive & Process Through Static Tables Acknowledge Frames Through Dynamic Tables Control Access To Shared Channel Handle Network Congestion As in Broadcast Mechanisms Usage Accounting Dr. Deepak B Phatak IT640-Session 17, Networking Basics 25 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 26 Transport Layer Session And Presentation Layers Take The Message From Higher Layer And Convert Into Smaller Units (Packets). Establishing Sessions, to provide Dialog Reassemble in The Right Sequence Services, Synchronization Establish Distinct Network Service for Each Transport Connection Resolve Common Presentation Issues Text Coding ASCII, EBCDIC True End-to-End Layer Dr. Deepak B Phatak IT640-Session 17, Networking Basics 27 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 28 Application Layer TCP/IP Reference Model Several Standards For Application Level Developed in ARPANET Services Agency of DoD, USA Virtual Terminals 1969, Four Mainframes E-Mail Evolved into the INTERNET File Transfer Defined by Cerf & Kahn in 1974 Directory Look-up ISO Model is Academically Neat But TCP/IP is the De Facto Standard Dr. Deepak B Phatak IT640-Session 17, Networking Basics 29 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 30 5
  6. 6. IT 640 Modern Information Systems TCP-IP Reference Model Internet (Network) Layer Connection less Packet Switched Layer Packet Formats Defined HTTP FTP TELNET Application layer Internet Packet (IP) TCP Transport Layer Max Length 65535 Bytes IP Network Layer Usually ~ 1500 Bytes Data-Link Physical medium Dr. Deepak B Phatak IT640-Session 17, Networking Basics 31 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 32 Network Layer IP Addresses (32 Bit) Control The Operation of Routing of NA HA Class A packets Across Networks 0 Begin with 0 Handle Network Congestion 7 bit network address(NA), 24 bit host address(HA) Usage Accounting 10 Class B Begin with 10 14 bit network address, 16 bit host address Dr. Deepak B Phatak IT640-Session 17, Networking Basics 33 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 34 IP Addresses IP Addresses 110 Written in Decimal Notation Class C 191.48.144.16 Begin with 110 21 bit network address, 8 bit host address Special Addresses 0.0.0.0 (This Host) 1110 Class D 255.255.255.255 All Hosts Begin with 1110 127. (Anything) is a Loop Back Used for multicast addresses Host Addresses Could Be Divided Class E (11110) For Future Use Subnet + Host Dr. Deepak B Phatak IT640-Session 17, Networking Basics 35 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 36 6
  7. 7. IT 640 Modern Information Systems The IP Datagram Header Transport Layer (TCP, UDP) VERSIO HEADER TYPE OF N LENGTH SERVICE TOTAL LENGTH Transmission Control Protocol IDENTIFICATION DF FRAGMENT OFFSET Establishes a Reliable Connection MF Ensures Error Free Delivery TIME TO LIVE PROTOCOL HEADER CHECKSUM User Datagram Protocol SOURCE ADDRESS Connectionless Protocol DESTINATION ADDRESS Used Heavily For One-Shot Request Reply Queries OPTIONS Transmission of Speech, Video Error Prone But Less Delay Dr. Deepak B Phatak IT640-Session 17, Networking Basics 37 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 38 Transport Layer TCP TCP Transmission Control Protocol Connections Identified By Pair of Sockets (Socket1, Socket2) Reliable End to End Byte Stream Takes Data Streams And Breaks These Into (IP) Ports < 256 Used For Special Services Packets < 64K ( Normal:1500 B) FTP : 21 Service Model Telnet : 23 End Points Called Sockets Are Created Connections Are Full Duplex Each Socket Number (Address) Exchanges Data In Segments Has IP Address of Host + Header (20 Bytes + Options) + Data A 16 bit PORT Number Dr. Deepak B Phatak IT640-Session 17, Networking Basics 39 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 40 TCP Header UDP SOURCE PORT DESTINATION PORT SOURCE PORT DESTINATION PORT SEQUENCE NUMBER TCP UNUSED FLAGS UDP LENGTH UDP CHECKSUM Header WINDOW SIZE Length ACKNOWLEDGEMENT NUMBER UDP Header Format CHECKSUM URGENT POINTER OPTIONS (0 or More 32-bit Words) Sends & Receives Capsulized Raw IP Datagrams Data (Optional) Dr. Deepak B Phatak IT640-Session 17, Networking Basics 41 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 42 7
  8. 8. IT 640 Modern Information Systems APPLICATION LAYER DNS Simplification of Addresses Domain Names Are ARPANET had a File Called hosts.txt Case Insensitive Domain Name System (DNS) Either Absolute or Relative Hierarchical System Each Domain Controls Allocation of .in, .jp, .uk, or generic (.com, .org) Names Under it .co, .ac, .ernet, NCST in India .iitb, .tifr, .pspl, .it, .cse, .me, .ae, Name Length 63, Total 255 Chars Example: quark.it.iitb.ac.in Dr. Deepak B Phatak IT640-Session 17, Networking Basics 43 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 44 Domain Name Resolution E-Mail Networks understand IP Address One of The Earliest Applications Elaborated in 1982 Arpanet Proposal Name Given to a RESOLVER Two Subsystems Application User Agents (Client Side) Sends it to a DNS Server Message Transfer Agents (Server Daemons) Five Basic Functions Gets Back Resource Records Composition, Transfer, Reporting, Displaying, Disposition Dr. Deepak B Phatak IT640-Session 17, Networking Basics 45 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 46 E-Mail E-Mail Transfer and Delivery SMTP Mailboxes, Mailing Lists, Simple Mail Transfer Protocol TCP Connection to Port 25 Message Format (To, From, cc, bcc ) Checks Existence of Recipient Transfers All Mail, Closes Connection MIME Delivery Protocols (To Fetch Mail) Multipurpose Internet Mail Extensions POP3 (Post Office Protocol) Permits Description of Content Type IMAP (Interactive Mail Access Protocol) Vacation Daemon Text, Image, Audio, Video, Application Dr. Deepak B Phatak IT640-Session 17, Networking Basics 47 Dr. Deepak B Phatak IT640-Session 17, Networking Basics 48 8
  9. 9. This document was created with Win2PDF available at http://www.daneprairie.com. The unregistered version of Win2PDF is for evaluation or non-commercial use only.

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