MIL-HDBK-2051 Fiber Optic Shipboard Cable Topology Design GuidanceThis handbook contains suggested design rules for defining a fiber optic cable topology. In addition, this document describes a suggested approach for developing and designing a fiber optic cable topology FOCT for a Naval platform and also identifies the applicable fiber optic component specifications. This handbook is primarily intended for use by the fiber optic cable topology design engineer, but provides useful information to a system design engineer as well.

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MIL-HDBK-2051(SH)

5.2.2  Conceptual design summary  .  The output of the conceptual phase of the design process is a block diagram and isometric cabling diagrams showing the conceptual configuration of the cable plant.  The drawings should show the interconnection box service areas, preliminary interconnection box locations and the interconnection requirements between service areas.  As a minimum, there should be one interconnection box for each service area.

5.3  Preliminary design .

5.3.1  Preliminary design process  .  During the preliminary design the configuration of the FOCT is developed to the point where interconnection box locations and trunk requirements are identified.  The information determined during this phase is:

a. Fiber function identification b. Fiber quantity

c. Trunk and local cable identification d. Termination type

e. Preliminary interconnection box size, configuration and location f. Trunk and local cable redundancy

g. Special link performance requirements h. Other special requirements

5.3.1.1   Fiber function .  Fibers are identified as either trunk fibers, those in trunk cables run between interconnection boxes, or local fibers, those in local cables run between end user equipment and interconnection boxes.

5.3.1.1.1   Trunk fiber categories  .  There are four categories of trunk fibers:

a. Allocated and used

b. Allocated and not used

c. Unallocated

d. Unused

5.3.1.1.1.1   Allocated and used (trunk)  .  Allocated and used fibers are fibers that are required by a user to interconnect system equipments.  System specifications are reviewed to determine the fiber optic interconnection requirements.  These interconnection requirements are then used to determine the number and type of allocated fibers required in the trunks between interconnection boxes.  Fibers contained within this category are:

a. Normal channel fibers (see 3.2.11)

b. Alternate channel fibers (see 3.2.3)

c. Non Redundant Channel (NRC) fibers (see 3.2.10)

5.3.1.1.1.2   Allocated and not used (trunk)  .  Allocated and not used fibers are fibers that are assigned to specific systems but are not actively used by

the system equipment.  Manual reconfiguration is required in order to activate the use of these fibers.  Fibers in this category are:

a. System required spare fibers

b. FOCT supplied redundant fibers

5.3.1.1.1.3   Unallocated .  Unallocated fibers are fibers included in the basic design that are not designated for use by a specific system.  These fibers are:

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