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MTA-98-366 > OSI Model > Flashcards

Flashcards in OSI Model Deck (8)
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1

OSI Layers

Physical
Data Link
Network
Transport
Session
Presentation
Application

2

Physical

Media Layer
Data Unit - Bit
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Concerned with the transmission and reception of the unstructured raw bit stream over the physical medium.
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Application: Physical Structure. Cables, Hubs, etc.
Example: Data Encoding - Physical medium attachment - Transmission technique - Baseband or Broadband - Physical medium transmission Bits & Volts
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Central device - Hub

3

Data Link

Media Layer
Data Unit - Bit/Frame
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Provides error-free transfer of data frames from one node to another over the Physical Layer
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Application: Frames ("envelopes", contains MAC address)(NIC card - Switch - NIC Card)(end to end)
Example: Establishes & terminates the logical link between nodes - Frame traffic control - Frame sequencing - Frame acknowledgment - Frame delimiting - Frame error checking - Media access control
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Central device - Switch, Bridge, Wap
Protocol - PPP/SLIP

4

Network

Media Layer
Data Unit - Packet/Datagram
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Application: Packets ("letter", contains IP address)
Example: Routing - Subnet traffic control - Frame fragmentation - Logical-physical address mapping - Subnet usage accounting
* Packet Filtering
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Central Device - Routers
Protocol - IP/IPX/ICMP

5

Transport

Host Layer
Data Unit - Segments
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Ensures that messages are delivered error-free, in sequence, and with no losses or duplications
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Application: TCP. Host to Host, Flow Control
Example: Message segmentation - Message Acknowledgement - Message traffic control - Session multiplexing
* Packet Filtering
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Protocol - TCP/SPX/UDP

6

Session

Host Layer
Data Unit - Data
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Allows session establishment between processes running on different stations
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Application: Synch & send to ports. Logical Ports
Example: Session establishment, maintenance and termination - Session support - perform security, name recognition, logging, etc
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Central Device - Logical Ports
Protocols - RPC/SQL/NFS/NetBIOS names

7

Presentation

Host Layer
Data Unit - Data
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Formats the data to be presented to the Application layer. It can be viewed as the "Translator" for the network.
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Application: Syntax layer. Encrypt & decrypt (if needed)
Example: Character code translation - Data conversion - Data compression - Data encryption - Character Set Translation
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Protocols - JPEG/ASCII/EBDIC/TIFF/GIF/PICT

8

Application

Host Layer
Data Unit - Data
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Serves as the window for users and application processes to access the network services.
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Application: End User Layer. Program that opens what was sent or creates what is to be sent
Example: Character code translation - Data conversion - Data compression - Data encryption - Character Set Translation
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Central Device - User Applications
Protocols - SMTP