I have a wowza server that will be distributing a continuous live stream of a TV channel.

If the internet goes down at our TV station then we would like to broadcast something to our viewers rather than a blank screen.

This file or playlist would be stored locally on the server so that internet is not required.

Obviously if the streaming server goes down our stream goes down...but thats not an issue in this regard.

What we want to achieve is the following.

1) Internet goes down at tv station and the upgoing stream stops.
2) Wowza detects no incoming stream and automatically switches to VOD files/playlist instead.
3) Viewers of the channel continue to get an uninterupted stream, which is now showing VOD files instead of the live stream.
4) As soon as the tv station restarts its live stream wowza switches back seamlessly and viewers regain the live stream.

How would I do this on wowza?