The%20data%20link%20layer

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The data link layer
Skills none IT concepts LAN, medium access,
Ethernet and WiFi protocols, why standards win
This work is licensed under a Creative Commons
Attribution-Noncommercial-Share Alike 3.0
License.
2
Where does this topic fit?

• Internet concepts
• Applications
• Technology (communication)
• Implications for
• Internet skills
• Application development
• Content creation

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TCP/IP protocol layers from 1,000 feet up
Application
Transport
Internet
Data link
Physical
Programs that do useful work like retrieve Web
pages, copy files, send and receive email, etc.
Make client-server connections and optionally
control transmission speed, check for errors, etc.
Route data between networks
Route data within the local area network
Specify what medium connects two nodes, how
binary ones and zeros are differentiated, etc,
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The view from 2,000 feet
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Networks inside the cloud
The router at the edge of each network
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The LANs and the Internet
Data link layer
Internet layer
Data link layer
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A simple LAN combining data link (Ethernet and
WiFi) and internet (IP) protocols in one box
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A complex LAN may have many switches and routers
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Data link layer protocols
Ethernet (copper and optical fiber)
WiFi (physical and data link)
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Transfer data and check for errors
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101011010101010101101010111010101011
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Medium access control
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WiFi and Ethernet won because they were

• Open
• Dynamic
• (WiFi was also license free)

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The data link layer
Skills none IT concepts LAN, medium access,
Ethernet and WiFi protocols, why standards win
This work is licensed under a Creative Commons
Attribution-Noncommercial-Share Alike 3.0
License.