C9300X-48HX PoE Budget for 9166 APs
An engineer is implementing a wireless design for a service provider. The design includes a Catalyst 9800, a stack of two Catalyst 9300X-48HX switches, and 9166 APs. Each AP must be named using the Floor-439412509-01X sting where X is the area number. The engineer wants to connect the APs to the switch stack using POE. How many APs must the engineer connect to the stack so the APs run using full functionalities?
Community Votes
50% of anonymous learners picked answer C. Votes are pick records left by other test-takers — they are not the verified answer.
Community Insight
Tests the ability to calculate PoE budget vs. device power draw, with the trap being the assumption that 'stack' implies unlimited shared power or that all ports can be utilized simultaneously without checking individual switch PSU limits.
Determines the maximum number of Catalyst 9166 APs that can be powered by a single Catalyst 9300X-48HX switch stack based on PoE budget constraints. The analysis reveals that full functionality requires specific power levels that exceed standard switch capabilities.
Most candidates select C (all ports) assuming the stack's total theoretical PoE capability covers all ports, failing to account that the default 1100W PSU only provides ~590W per chassis, which cannot support 48 high-power APs.
Community Discussion (5 comments)
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Expert Analysis
Why the Answer Is Correct
The correct answer is D because the question specifies a "default build" scenario implicitly by not mentioning upgraded PSUs. A Catalyst 9300X-48HX with a single 1100W PSU has a PoE budget of approximately 590W. A Catalyst 9166 AP in full functional mode (all radios active, USB on) draws roughly 30.5W under 802.3bt (UPOE). Dividing 590W by 30.5W yields approximately 19 APs per switch. Since there are two switches in the stack, and each operates independently regarding its local PSU, you cannot connect all ports (48 per switch) to full-functioning APs. You must limit the connection to half the ports (or fewer) per switch to stay within the thermal and electrical budget of each unit.Why the Other Options Are Wrong
Option A and B are incorrect because connecting all ports on a single switch would require ~1,464W (48 * 30.5W), far exceeding the 590W budget of a single 1100W PSU. Option C is incorrect because it assumes the entire stack acts as a single monolithic power pool, which is false; each switch manages its own PoE budget. Even if UPOE were used, the 590W limit remains the bottleneck for the default configuration.Community Comment Notes
Commenters like gcordess and Love2Cod3 correctly identified the 590W budget constraint for the default 1100W PSU. They noted that while the switch supports up to 90W UPOE theoretically, the actual available power is limited by the PSU wattage. As crabb63 noted, "C9300X-48HX... with 90W UPOE+ Modular Uplinks" is a feature, but the power source is the limiting factor. The consensus among technical commenters points to D due to these physical limitations.Official Reference
Exam Strategy
Always check the Power Supply Unit (PSU) specifications when PoE questions mention specific switch models. If no dual PSU or high-wattage upgrade is specified, assume the default 1100W PSU and its ~590W PoE budget. Calculate: Total PoE Budget / Power per Device = Max Devices Per Switch.
Frequently Asked Questions
Why doesn't the PoE budget pool across the stack?
Each switch in a Catalyst 9300X stack manages its own PoE budget independently. The 1100W PSU provides ~590W locally, so you cannot draw from Switch 1's spare power to feed Switch 2.
What if I use a 1900W PSU?
A 1900W PSU increases the PoE budget to ~1,100W. This would allow more APs per switch (~36 at 30.5W), potentially allowing all ports if the design includes this upgrade, but the question implies default hardware.