line protection vs radio protection - microwave radio

In MW links we have two parts:

1- The outdoor part: this is where we have the Outdoor units (ODUs), Antennas, Couplers, etc.. So radio protections happens here where you have a 1+1 HSB (hot stand by)protection for the ODU in case of failure in one ODU, the standby one comes into operation

2- The indoor part: this is where we have the indoor shelf, IF cards Modem card, E1 card, STM-1, etc... So line protection or some times called EPS (Equipment Protection Switching) is where you have for example two Modem cards one as main and the other in stand by, this type of protection is called 1+1 EPS