They just define how you handle clean up of backups. Using a recovery window says you will keep everything necessary to recovery to any point in time during the last X days. So in a recovery window of 7 days, I can recovery to a point in time anywhere from 7 days ago up to and including right now.
The redundancy says how many copied you will keep. Let's say I have a redundancy of 7 days, that sounds like the same as the previous example, but if I run 7 backups in one day, then I can not recovery to a point in time before today, because I've removed all the old backups...http://www.oracle-base.com/articles/9i/ ... Parameters