Networking standards osi
- 1. Networking Standards Over the years these have been written and developed by 3 organisations (mainly).
- 2. These organisations are:- • International Organisation for standards, ISO who developed OSI – Open Systems Interconnect. • Institute of Electrical and Electronic Engineers defines standards for LANs (TCP/IP). • Internet Engineering Task Force IETF manages the process of creating/developing TCP/IP standards
- 3. IETF • Anyone can participate in the creating/developing of TCP/IP standards. IETF put the standards used and new on a web site www.ietf.org and request your comments (RFC’s) which if useful may be include in future developments. • TCP/IP is made up of many standards. • ftp, smtp, http,tcp, ip,udp + others.
- 4. Open System Interconnect • This is the sort of overall standard for networking. But because it is very large and complex is not normally used, however you should know its basic structure. • This is a layered protocol and each layer can be used or not depending on what you are doing.
- 5. OSI layers Layer What is does. 7 Application Controls how the OS and applications interact with the network 6 Presentation Puts the data supplied together so it can be presented to the system. (not the user). Encryption and decryption lives here. 5 Session Defines the connection, negotiations between nodes etc. 4 Transport Manages the flow of information and ensures packets are all received and put in order. 3 Network Defines how data packets get from place to place. The IP and IPX lives here. (routers work from here) 2 Data Link Defines standards that assign meaning to the bits carried by the physical layer. (switches work here) 1 Physical Defines the physical properties of the medium used to make a connection.
- 6. How to remember this (if you want to I look it up in a book myself) • All People Seem To Need Data Processing ( layer 7 to 1) • Please Do Not Throw Sausage Pizzas Away (layer 1 to 7)
- 7. OSI • While its important to know a little about it, in general its not used, too complex. • What is used is a sub set of it:- »TCP/IP
- 8. TCP/IP Or • Transfer Control Protocol/Internet Protocol As its know by its friends. This is a 4 or 5 layer protocol depending on who you read. This a very very important protocol, as all computers use it for communications. It is the English of the computer world.
- 9. Fit them together. OSI Model TCP/IP TCP/IP alt 7 Application 6 Presentation Application Application 5 Session 4 Transport Transport Transport 3 Network Internetwork Internetwork 2 Data Link Network Data Link 1 Physical Interface Physical
- 10. But what do they do?? TCP/IP ` 4 Application Protocols for specific function. ftp, smtp http, pop3, 3 Transport Error recovery and recovery of data. TCP, UDP. 2 Internetwork IP works here and attaches destination and source addresses 1 Network Interface Frames are set up here. Ethernet, Frame relay, Token ring
- 11. Help what does this mean?? TCP/IP `Information comes down to be sent off 4 Application Segmented into pieces. 3 Transport Pieces numbered 2 Internetwork IP source and destination addresses added. 1 Network Interface Physical source and destination addresses added. Put into a frame, type depending on network.
- 12. Put it together. Fred Sent “how are you” To John John how are youSegmented Numbered IP Mac Piece 1 how are you how Piece 1IP Mac how how Piece 1IP It is now a frame send it off
- 13. Put it together. Fred Sent “how are you” To John John Segmented Numbered IP Mac how Piece 1 how Piece 1IP Mac how how Piece 1IP
- 14. Put it together. Fred Sent “how are you” To John John are are youSegmented Numbered IP Mac Piece 2 are Piece 2IP Mac are Piece 2IP It is now a frame send it off how
- 15. Put it together. Fred Sent “how are you” To John John Segmented Numbered IP Mac are Piece 2 are Piece 2IP Mac are are Piece 2IP howyou
- 16. Put it together. Fred Sent “how are you” To John John you areyouSegmented Numbered IP Mac Piece 3 you Piece 3IP Mac you Piece 3IP It is now a frame send it off how
- 17. Put it together. Fred Sent “how are you” To John John Segmented Numbered IP Mac you Piece 3 you Piece 3IP Mac you you Piece 3IP howyou are
- 18. Put it together. Fred Sent “how are you” To John John Segmented Numbered IP Mac you how are
- 19. Put it together. Fred Sent “how are you” To John John Segmented Numbered IP Mac youhow are
- 20. Put it together. Fred Sent “how are you” To John John Segmented Numbered IP Mac youhow are how are you
- 21. Put it together. Fred Sent “how are you” To John John Segmented Numbered IP Mac how are you
- 22. There are a number of different types of frames. Ethernet frame Preamble Destination Address Source address Type Data (packet) FCS 8 Bytes 6 Bytes 6 Bytes 2 Bytes 46 - 1500Bytes 4 Bytes Frame Check Sequence IEEE 802.3 frame Preamble SOF Destination Address Source address Type 802.2 header and data FCS 8 Bytes 6 Bytes 6 Bytes 6 Bytes 2 Bytes 46 - 1500Bytes 4 Bytes Start of Frame Token ring data frame Start delim End delim Frame Ctrl Destination Address Source address Information Frame check End delim Frame status 1 Bytes 1 Bytes 1 Bytes 6 Bytes 6 Bytes 0-18000 Bytes 4 Bytes 1 Bytes 1 Bytes Different ones are used for different types of networks.