What’s the difference between normal TV and Internet TV?/How does Internet work?

Don’t now how the current tv works but internet tv works as follow:

Say that’s Consumer Jane there on the couch. She gets digital video from her local telephone company, which sends it to her over a DSL connection (DSL is rooted in IP, Thus, IPTIV is synonymous with sending TV over DSL).

Remote in hand, Jane thumb-surfs via the channel-up arrow. The set-top (or media center) that came with the service issues what’s known as a join request. It wants to dip into a precached set of video frames. The request zings up the phone wire, to that buffer. Maybe it’s in an edge aggregator or maybe it’s in the D-slam, or digital subscribe line access multiplexer. Either way, the tuners aren’t inside anything at Jane’s house. The bits that make up the video frame in the buffer zing back into the box. The boxes used by cable and satellite operators use work differently. On-board tuners work by literally jumping frequencies each time somebody invokes a zap with the remote control. Then they need to demodulate the incoming signal, stabilize it and deal with any error-correction activities. If the processing chip isn’t beffy enough, that to do list can bog down. Symptom: slower zapper action

So conclusion you need a lot of bandwidth.

[3] Ellis, Leslie, Multi Channel News, 2/06/2006, Vol 27 issue 6, p23-24, AN 199642635 BSP, How IPTV differs from Cable TV