This is especially crucial for on-demand video. Raise other issues. The first thing mentioned was the need for capacity planning to meet the load on the networks. Much of the load will be unscheduled. Access should be 7 X 24.
Some implementations use illustrated video which has lower bandwidth requirements.
The compression techniques used are related to use on other media - DVD, etc. Some implementations mix video with audio and Midi-based applications. A serious limitation is the bandwidth of modem links to users. In general, home computer capabilities are a concern. Systems often must be concerned with connections to outside agencies.