The decision regarding the number of optical fibers to install (fiber strand count) in a backbone depends largely on all of the following EXCEPT:

Multiplexing level directly affects strand count because higher-density multiplexing (e.g., WDM) allows more channels per fiber, reducing the total number of strands needed in the backbone.

Intended end-user applications determine bandwidth and redundancy requirements, which directly drive how many fiber strands must be provisioned in the backbone.

The physical topology (e.g., hierarchical star) determines how cables are routed and how many strands must be home-run or distributed between nodes.

Distance between telecommunications rooms (TRs) determines cable run length and influences signal attenuation planning and fiber type selection (multimode vs. singlemode), but it does not determine how many fiber strands are needed. Strand count is driven by application demand, multiplexing levels, topology, and system configuration - none of which are a direct function of physical distance between TRs.

Cabling system configuration - such as centralized vs. distributed architectures - affects where fibers terminate and how many are required at each distribution point.