Networking Concepts Lesson 05 - OSI - Eric Vanderburg
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The document discusses the OSI reference model and its seven layers - physical, datalink, network, transport, session, presentation, and application layer. It describes the functions of each layer such as physical addressing at the datalink layer, logical addressing and routing at the network layer, and programs accessing network services at the application layer. The document also mentions TCP/IP corresponds to the transport, internet, and application layers of the OSI model and standards such as 802.1 to 802.11 for networking.
Networking Concepts Lesson 05 - OSI - Eric Vanderburg
- 1. Chapter 5 Making Networks Work Networking Concepts – Eric Vanderburg ©2005
- 2. OSI Reference Model Application Application Presentation Presentation Session Session Transport Transport Network Network Datalink Datalink Physical Medium Networking Concepts – Eric Vanderburg ©2005 Physical
- 3. OSI Reference Model How to remember this Please Do Not Throw Sausage Pizza Away Think of your own… 3 Sections of the Model Application Transport Application Layer (7) Presentation Layer (6) Session Layer (5) Transport Layer (4) Network Network Layer (3) Datalink Layer (2) Physical Layer (1) Networking Concepts – Eric Vanderburg ©2005
- 4. Encapsulation Enclosing some data within another thing so that the included data is not apparent. Networking Concepts – Eric Vanderburg ©2005
- 5. Application – Layer 7 Where programs access network services FTP, HTTP, Client Software Problems at this layer: Misconfigured settings Incompatible commands Networking Concepts – Eric Vanderburg ©2005
- 6. Presentation – Layer 6 Formats data Protocol conversion Encryption Compression Character set (ASCII, Unicode, EBCDIC) Problems at this layer: Cannot decrypt Wrong conversion Networking Concepts – Eric Vanderburg ©2005
- 7. Redirector Sends requests for services to the appropriate network device. RDR can sometimes stand for redirector Rdr.sys Windows redirector registry entries stored in HKEY_LOCAL_MACHINESYSTEMCurrentCon trolSetServices LanmanWorkstationParameters and HKEY_LOCAL_MACHINESYSTEMCurrentCon trolSetServicesRdr Networking Concepts – Eric Vanderburg ©2005
- 8. Session – Layer 5 Manages communication Identification Window size Keep alive messages ACK, NAK Name resolution DNS NetBIOS Logon Problems at this level: Incorrect or no name resolution Networking Concepts – Eric Vanderburg ©2005
- 9. Transport – Layer 4 Segmenting Sequencing Error checking Flow control – as much data as can handle TCP & SPX Problems at this layer: Overly large segments Networking Concepts – Eric Vanderburg ©2005
- 10. Network – Layer 3 Logical addressing Routing QOS Deals with packets IP & IPX Problems at this layer: Incorrect routing (bad config) Incorrect routing table Incorrect routing protocol Incorrect IP configuration Networking Concepts – Eric Vanderburg ©2005
- 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 Networking Concepts – Eric Vanderburg ©2005
- 12. Datalink Sublayers MAC Manages multiple NICs Creates frame and sends to physical Sense carrier Pass tokens LLC Error recovery Integrity checking Networking Concepts – Eric Vanderburg ©2005
- 13. Physical – Layer 1 Encoding - Convert bits to signals 101001011001 Problems at this level: Interference Noise Cable not connected Networking Concepts – Eric Vanderburg ©2005
- 14. OSI & TCP/IP OSI Model Application Presentation Session Transport Network Datalink Physical Networking Concepts – Eric Vanderburg ©2005 TCP/IP Application Transport Internet Network
- 15. 802 Specifications 802.1 Bridging and Internetworks 802.2 Flow control LLC Sublayer 802.3 Ethernet 802.4 Token Bus 802.5 Token Ring 802.6 MAN 802.7 Broadband 802.8 Fiber Optics 802.9 VOIP 802.10 Security 802.11 Wireless 802.15 WPAN 802.18 Radio Wireless Networking Concepts – Eric Vanderburg ©2005
- 16. Terms Congestion Control – adjusts network transmissions based on current utilization Flow control – send as much data as each computer can handle at a time PDU – Packet Data Unit, Payload Data Unit, Protocol Data Unit Networking Concepts – Eric Vanderburg ©2005