1. OSI & TCP/IP Model(s) By Muhammad Hanif To: BS IT 4 th Semester

2. Quotes of the Day  “Seek knowledge from the cradle to the grave.” Hazrat Muhammad (P.B.U.H)  “Education is the most powerful weapon which you can use to change the world.” Nelson Mandela  “When you know better you do better.” Maya Angelou  “Intelligence plus character-that is the goal of true education.” Martin Luther King Jr.

3.  Open Systems Interconnection (OSI) is a set of internationally recognized standards for networking and for operating system involved in networking functions.  In 1978, the International Standards Organization (ISO) began to develop its OSI framework architecture.  The concept of a 7 layer model was provided by the work of Charles Bachman.

4. OSI Model Data unitLayerFunction Host layers Data 7. ApplicationNetwork process to application 6. Presentation Data representation, encryption and decryption 5. SessionInter host communication Segments4. Transport End-to-end connections and reliability, Flow control Media layers Packet3. Network Path determination and logical addressing Frame2. Data LinkPhysical addressing Bit1. Physical Media, signal and binary transmission Going from layer 1 to 7: Please Do Not Throw Sausage Pizza Away Going from layer 7 to 1: All People Seems To Need Data Processing

5. 7 Layers 7. Application LayerAll 6. Presentation LayerPeople 5. Session LayerSeems 4. Transport LayerTo 3. Network LayerNeed 2. Data Link LayerData 1. Physical LayerProcessing

6. Tasks involved in sending letter

7. LAYER 7 – The APPLICATION Layer The top layer of the OSI model Provides a set of interfaces for sending and receiving applications to gain access to and use network services, such as: network file transfer, message handling and database query processing Protocols are HTTP, Telnet, FTP etc

8. LAYER 7 – The APPLICATION Layer The application layer provides set of Interfaces and is responsible for providing services to the user.

9. LAYER 6 – The PRESENTATION Layer Manages data-format information for networked communications (the network’s translator) For outgoing messages, it converts data into a generic format for network transmission. For incoming messages, it converts data from the generic network format to a format that the receiving application can understand This layer is also responsible for Certain protocol conversions Data encryption/decryption, Data compression/decompression

10. LAYER 6 – The PRESENTATION Layer The presentation layer is responsible for translation, compression, and encryption.

11. LAYER 5 – The SESSION Layer Enables two networked resources to hold ongoing communications (called a session) across a network Applications on either end of the session are able to exchange data for the duration of the session. This layer is responsible for initiating, maintaining and terminating sessions

12.  The session layer is responsible for dialog control and synchronization. LAYER 5 – The SESSION Layer

13. LAYER 4 – The TRANSPORT Layer Manages the transmission of data across a network Manages the flow of data between parties by segmenting long data streams into smaller data chunks called segments. (based on allowed “packet” size for a given transmission medium) Reassembles segments into their original sequence at the receiving end Provides acknowledgements of successful transmissions and requests resends for packets which arrive with errors

14. LAYER 4 – The TRANSPORT Layer Establishes End-to-End Connectivity Can ensures reliable delivery i.e. error detection and retransmission Typical Layer 4 Protocols Transmission Control Protocol (TCP) User Datagram Protocol (UDP)

15. LAYER 4 – The TRANSPORT Layer The transport layer is responsible for the delivery of a message from one process to another.

16. LAYER 3 – The NETWORK Layer Handles logical network addresses for delivery Responsible for deciding how to route transmissions between computers This layer also handles the decisions needed to get data from one point to the next point along a network path This layer also handles packet switching and network congestion control

17. LAYER 3 – The NETWORK Layer Provides connectivity and path selection E.g. Routing Typical Layer 3 Devices and Protocols Routers, IPv4, IPv6 For logical address go to command Prompt Ipconfig/all

18. LAYER 3 – The NETWORK Layer The network layer is responsible for the delivery of individual packets from the source host to the destination host.

19. LAYER 2 – The DATA LINK Layer Handles special data frames (packets) between the Network layer and the Physical layer At the sending end this layer handles conversion of data into raw formats that can be handled by the Physical Layer At the receiving end, this layer packages raw data from the physical layer into data frames for delivery to the Network layer

20. LAYER 2 – The DATA LINK Layer Defines data format for transmission E.g. Ethernet, Frame Relay, PPP Controls access to Physical media Defines Physical Addressing E.g. Ethernet MAC address Typically has error detection E.g. Cyclical Redundancy Check (CRC) Typical Layer 2 Devices and Protocols Bridges, Switches, Wireless Access Points, Ethernet, PPP

21. LAYER 2 – The DATA LINK Layer The data link layer is responsible for moving frames from one hop (node) to the next.

22. LAYER 1 – The PHYSICAL Layer Converts bits into electronic signals for outgoing messages Converts electronic signals into bits for incoming messages This layer manages the interface between the computer and the network medium (coax, twisted pair, etc.) This layer tells the driver software for the MAU (media attachment unit, ex. network interface cards (NICs, modems, etc.)) what needs to be sent across the medium The bottom layer of the OSI model

23. LAYER 1 – The PHYSICAL Layer Defines physical media properties Electrical Functions Physical Data Rates Physical Connectors Cable Distances Optical Wavelengths Wireless Frequencies Typical Layer 1 Devices Cat5 Cables, Fiber Optics Coaxial cable, etc

24. LAYER 1 – The PHYSICAL Layer  The physical layer is responsible for movements of individual bits from one hop (node) to the next.

25. Remember  A convenient aid for remembering the OSI layer names is to use the first letter of each word in the phrase:  All People Seems To Need Data Processing

26. OSI Model at a Glance

27. Introduction TCP/IP  The Internet Protocol Suite (commonly known as TCP/IP) is the set of communications protocols used for the Internet and other similar networks.  It is named from two of the most important protocols in it: the Transmission Control Protocol (TCP) and the Internet Protocol (IP), which were the first two networking protocols defined in this standard.

28. OSI V/S TCP/IP Layers OSITCP/IP Application Layer Presentation Layer Session Layer Transport Layer Network Layer Internet Layer Data Link Layer Link Layer Physical Layer

29. TCP/IP Stack

30. TCP/IP Protocol Suite LayerProtocol Application DNS, TFTP, TLS/SSL, FTP, Gopher, HTTP, IMAP, IRC, NNTP, POP3, SIP, SMTP, SMPP, SNMP, SSH, Telnet, Echo, RTP, PNRP, rlogin, ENRP TransportTCP, UDP, DCCP, SCTP, IL, RUDP, RSVP Internet IP (IPv4, IPv6), ICMP, IGMP, and ICMPv6 Routing protocols like BGP and RIP which run over TCP/UDP, may also be considered part of the Internet Layer. LinkARP, RARP, OSPF (IPv4/IPv6), IS-IS, NDP

31. Assignment No. 1  Write detail note on OSI model.  Submission: Wednesday 2 nd April, 2014

32. Thanks