CoE 542 Lesson 4 - OSI Model

OSI (Open System Interconnect) - reference model

Headers and Trailers
Packet or Frame


7 Layer of OSI Model

1. Application- used by human or software
2. Presentation- encryption, format
3. Session- establish, maintains, terminate connection
4. Transport- delivery of the entire message
   segmentation and reassembly 
5. Network- source-to-destination delivery of a packet
   logical address
   routing
6. Data Link- node-to-node delivery of a packet
   physical address
7. Physical- data transmission, media, signal, etc.