Networking Essentials Lesson 02 - Standards and OSI - Eric Vanderburg
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The document discusses networking standards and the OSI model. It describes the seven layers of the OSI model from physical to application layer. It explains the OSI model layers in detail and some common problems that can occur at each layer, such as physical interface issues, routing errors, incorrect protocols. The document also covers related topics such as encapsulation, networking standards bodies, and common networking acronyms.
Networking Essentials Lesson 02 - Standards and OSI - Eric Vanderburg
- 1. Networking Essentials Chapter 2 Networking Standards and the OSI model Networking Essentials – Eric Vanderburg © 2005
- 2. Standards Specifications on how a product or service should be performed, implemented, or constructed. Standards Organizations ANSI (American National Standards Institute) EIA/TIA (Electronic Industries Alliance / Telecommunications Industry Alliance) IEEE (Industry of Electrical and Electronics Engineers) ISO (International Organization for Standardization) ITU (International Telecommunication Union) ISOC (Internet Society) • IAB (Internet Architecture Board) • IETF (Internet Engineering Task Force) IANA (Internet Assigned Numbers Authority) ICANN (Internet Corporation for Assigned Names & Numbers)
- 3. OSI Reference Model Application Application Presentation Presentation Session Session Transport Transport Network Network Datalink Datalink Physical Medium Physical
- 4. OSI Reference Model How to remember this Please Do Not Throw Sausage Pizza Away Androids Provide Services To Needy Desperate People Think of your own… 3 Sections of the Model Application • Application Layer (7) • Presentation Layer (6) • Session Layer (5) Transport • Transport Layer (4) Network • Network Layer (3) • Datalink Layer (2) • Physical Layer (1)
- 5. Encapsulation Enclosing some data within another thing so that the included data is not apparent.
- 6. Application – Layer 7 Where programs access network services FTP (File Transfer Protocol), HTTP (HyperText Transfer Protocol), Client Software APIs (Application Programming Interface) Problems at this layer: Misconfigured settings Incompatible commands
- 7. Presentation – Layer 6 Formats data Encryption & Compression Character set ASCII (American National Standard Code for Information Interchange) Unicode EBCDIC (Extended Binary Coded Decimal Interchange Code) Problems at this layer: Cannot decrypt Wrong conversion
- 8. Session – Layer 5 Session – connection for ongoing data exchange Manages communication Identification / Authorization Window size Keep alive messages ACK (Acknowledgement), NAK (Negative Acknowledgement) Name resolution DNS (Domain Naming Service) NetBIOS (Network Basic Input Output System) Problems at this level: Incorrect or no name resolution
- 9. Transport – Layer 4 Segmenting Reduce size to the MTU (Maximum Transmission Unit) Sequencing Integrity checking (Checksum) Flow control – as much data as can handle TCP (Transmission Control Protocol) & SPX (Sequenced Packet Exchange) Problems at this layer: Overly large segments
- 10. Network – Layer 3 Logical addressing Routing QOS (Quality of Service) Deals with packets IP (Internet Protocol) & IPX (Internetwork Packet Exchange) Problems at this layer: Incorrect routing (bad config) Incorrect routing table Incorrect routing protocol Incorrect IP configuration
- 11. Datalink – Layer 2 Physical Addressing Deals with frames Discards bad frames Convert to bits Problems at this layer: Collisions Bad frames Faulty NIC Incorrect bridging tables
- 12. Datalink Sublayers MAC (Media Access Control) Manages multiple NICs Append physical address Creates frame and sends to physical Carrier Sense Pass tokens LLC (Logical Link Control) Error recovery – A 4 byte number is generated to check for errors. The number is stored in the FCS (Frame Check Sequence) using the CRC (Cyclic Redundancy Check) algorithm.
- 13. Physical – Layer 1 Encoding - Convert bits to signals 101001011001 Light impulses Electronic signals Radio waves Problems at this level: Interference Noise Cable not connected
- 14. OSI & TCP/IP OSI Model TCP/IP Application Application Presentation Session Transport Transport Network Internet Datalink Network Physical
- 15. IEEE Specifications 802.3 Ethernet 802.5 Token Ring 802.11 Wireless
- 16. Acronyms ACK, Acknowledgement NAK, Negative Acknowledgement ANSI, American National Standards Institute ASCII, American National Standard Code for Information Interchange API, Application Program Interface CRC, Cyclic Redundancy Check EIA, Electronic Industries Alliance EBCDIC, Extended Binary Coded Decimal Interchange Code HTTP, HyperText Transfer Protocol FTP, File Transfer Protocol DNS, Domain Naming Service
- 17. Acronyms NetBIOS, Network Basic Input Output System IANA, Internet Assigned Numbers Authority ICANN, Internet Corporation for Assigned Names and Numbers IEEE, Institute of Electrical and Electronics Engineers IP, Internet Protocol ISO, International Organization for Standardization ITU, International Telecommunication Union LLC, Logical Link Control MAC, Media Access Control MTU, Maximum Transmission Unit OSI, Open Systems Interconnection PDU, Protocol Data Unit RIR, Regional Internet Registry TIA, Telecommunications Industry Association