ApplicationTransport
NetworkData Link
Physical
Application Layer
- services for applications
- http provides interface between software and the network
○ HTTP Header GET home.html
○ HTTP Header OK/ Data
Same layer interaction on different computers
- Communicate with the same layer on another computer.
Adjacent layer interaction on the same computer -
- One lower layer provides a service to the layer just above. The higher layer makes the next lower layer perform a function
*Wireless protocols are Layer 2
Encapsulation
-
- TCP/ Data (segment)IP/ Data (Packet)
- LH/ Data/ LT (Frame) (Link header & Link Trailer)
Protocol Data Units -
- L7H/ Data (L7PDU)L6H/ Data (L6PDU)
- L5H/ Data (L5PDU)
- L4H/ Data (L4PDU)
-
- L4H/ Data (L4PDU)L3H/ Data (L3PDU)
- L2H/ Data/ L2T (L2PDU)