This graphic was originally taken and adapted from ISO OSI 7-layer Model forced with TCP/IP.

ISO OSI 7 Layer Reference Model: End-to-end vs. Chained Communications
Layer  
7
 Application
< ------- End -------- to -------- End ------- >
 Application
6
 Presentation
< ------- End -------- to -------- End ------- >
 Presentation
5
 Session
< ------- End -------- to -------- End ------- >
 Session
4
 Transport
< ------- End -------- to -------- End ------- >
 Transport
3
 Network < -- > Network < -------- > Network < -- > Network
2
 Data Link < -- > DL < - > DL < -------- > DL < - > DL < -- > Data Link
1
 Physical < = > PH < - > PH < ==== > PH < - > PH < = > Physical
 
Computer 1
    
Router 1
   
Router 2
   
Computer 2

 

 

Want a more in-depth explanation of how that all works? Try here.