Drag and Drop Question Refer to the exhibit. Drag and drop the names of the field-replaceable units from the left onto the corresponding letters on the image of the Cisco Catalyst 9400 modular…

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Explanation

Cisco Catalyst 9400 Field-Replaceable Units (FRUs) - Placement Explanation

The Catalyst 9400 is a modular chassis switch (e.g., the 9407R has 7 line card slots). The chassis has a fixed physical layout that dictates where each FRU lives.

Position 1 - Power Supply Modules

Why here: Power supplies are housed in a dedicated bay on the right side of the chassis, separate from the card slots. They are always at the "edge" of the chassis for hot-swap access without disturbing other components. The 9400 supports multiple PSUs for redundancy (N+1).

Common mistake: Students sometimes confuse power supplies with line cards because both slot in from the front. The PSU bay is clearly separated and narrower than line card slots.

Position 2 - Fan Tray Assembly

Why here: The fan tray sits at the bottom of the chassis (or rear, depending on the chassis variant). Airflow in the 9400 is front-to-back or side-to-side; the fans pull or push air across all modules. Placing the fan tray at the bottom keeps it accessible for hot-swap replacement without taking the chassis offline.

Common mistake: Confusing the fan tray with a line card slot - the fan tray spans the full width of the chassis and has a distinct pull-tab handle.

Position 3 - Line Card Slots 1 and 2

Why here: Slots 1 and 2 are the upper line card slots, physically located above the supervisor module bays. In the 9407R, the slot numbering goes top to bottom: 1, 2, [supervisor zone], 5, 6, 7.

Position 4 - Supervisor Modules

Why here: The supervisor engine occupies dedicated central slots (slots 3 and 4 in the 9407R). Cisco deliberately places the supervisor in the middle of the chassis for:

• Equal electrical path length to all line cards (above and below)
• Thermal balance - the supervisor generates significant heat and benefits from surrounding airflow
• Redundancy - dual supervisors can occupy slots 3 and 4 simultaneously

Common mistake: Many assume supervisors go in the top slot (like a "controller" at the top). They do not - they occupy fixed, numbered central slots and cannot be placed in standard line card slots.

Position 5 - Line Card Slots 5, 6, and 7

Why here: These are the lower line card slots, below the supervisor bays. The numbering skips 3 and 4 (reserved for supervisors), which is why the lower bank starts at 5. The 9407R therefore has 5 usable line card slots total (1, 2, 5, 6, 7) and 2 supervisor slots (3, 4).

Common mistake: Students often wonder why slots 3 and 4 are "missing" from the line card list - they aren't missing, they're the supervisor slots. The slot numbering is sequential top-to-bottom; supervisors just happen to own the middle slots.

Quick Summary Table

The key insight is that the supervisor is always in the center, line cards flank it above and below, and the power/cooling components are in their own dedicated bays entirely outside the card-slot numbering scheme.

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