RECOMMENDATION ITU-R S.579-5 - Availability objectives for a hypothetical reference circuit and a hypothetical ...
ANNEX 1
1 Definition of availability
2 General considerations
3 Unavailability due to equipment
4 Unavailability due to propagation
5 Unavailability due to Sun transit
    5.1 Links carrying public switched network (PSN) traffic
    5.2 Links carrying time division multiple access and demand assignment multiple access traffic
    5.3 Links carrying leased traffic
6 Effect of propagation on unavailable time