Number OSI Layer Description TV Layer Description Examples
7 Application Users View Channel What the view sees BBC1
6 Presentation Code or format conversion Platform Various platforms Dsat DTT
5 Session Security Encryption/Timex Adaptation UKTV BSB encrytion
4 Transport Point to Point Error correction Feedback / interactive Interactivity / Data error correction VOD, VNL
3 Network Packet routing Routing Point to point / multicast Multiplexing
2 Data Frames Data format Data rate / format 270 SDV, ATM
1 Physical electical connections Circuits Physical circuits Circuit name