802 Layering

1
802 Layering

• 802 Committee Subdivided the Data Link Layer
• Media access control (MAC) layer
• Logical link control (LLC) layer

OSI
802
Data Link
LLC
MAC
PHY
PHY
2
802 Layering

• Media Access Control (MAC) Layer
• Only one station may transmit at a time or
  signals will be scrambled
• MAC layer standards ensure that only one can
  transmit (access the medium) at a time
• Also defines the lowest-layer frame format

3
802 Layering

• Logical Link Control (LLC) Layer
• Adds optional error correction (rarely used)
• Connects to next-higher-layer (internet)
• Single LLC standard for all LANs 802.2

IP
IPX
Etc.
802.2 Logical Link Control Layer Standard
802.3
802.5
802.11
4
Higher Layers

• With OSI LAN standards, six-layer model
• Hybrid TCP/IP-IEEE framework
• Application
• Transport
• Internet
• Logical Link Control
• Media Access Control
• Physical
• Client and server must use same standard for each
  layer