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-NoncommercialShare Alike 3.0 License.
Where does this topic fit?
• Internet concepts
– Applications
– Technology (communication)
– Implications for
• Internet skills
– Application development
– Content creation
TCP/IP protocol layers from 1,000 feet up
Application
Programs that do useful work like retrieve Web
pages, copy files, send and receive email, etc.
Transport
Make client-server connections and optionally
control transmission speed, check for errors, etc.
Internet
Route data between networks
Data link
Route data within the local area network
Physical
Specify what medium connects two nodes, how
binary ones and zeros are differentiated, etc,
The view from 2,000 feet
Networks inside the cloud
The router at the edge of each network
The LANs and the Internet
Data link
layer
Internet layer
Data link
layer
A simple LAN
combining data link
(Ethernet and WiFi)
and internet (IP)
protocols in one
box
A complex LAN
may have many
switches and
routers
Data link layer protocols
Ethernet (copper
and optical fiber)
WiFi (physical and
data link)
Transfer data and check for errors
101011010101
010101101010
111010101011
101011010101
010101101010
111010101011
Medium access control
WiFi and Ethernet won because they were
Open
Dynamic
(WiFi was also license free)
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-NoncommercialShare Alike 3.0 License.