High reliability and availability of communication services is a key requirement that needs to be ensured by service providers. Since the direct line-of-sight (LOS) beam is prone to blockage in indoor optical wireless communication systems, a backup link needs to be at hand in case of blockage, and hence channel allocation algorithms should be blockage-aware. In this paper, the impact of beam blockage due to a disc with varying size and distance from the receiver is studied where blockage is quantitatively evaluated using percentage blockage for 512 room locations at 25 cm separation. It was found that assigning two links with maximum separation between the serving access points can reduce or eliminate blockage compared to the case when resilience is not implemented. Increasing the number of allocated access points per user further increases resilience.