Networking Concepts Lesson 05 - OSI - Eric Vanderburg

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Networking Concepts Lesson 05 - OSI - Eric Vanderburg

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Networking Concepts Lesson 05 - OSI - Eric Vanderburg

  1. 1. Chapter 5 Making Networks Work Networking Concepts – Eric Vanderburg ©2005
  2. 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. 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. 4. Encapsulation  Enclosing some data within another thing so that the included data is not apparent. Networking Concepts – Eric Vanderburg ©2005
  5. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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

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