Power over Ethernet · downstream topology
How much power survives the PoE pass-through switch?
Start with power guaranteed at the powered switch, subtract its own use and reserve, then respect its separate downstream output declaration.
Powered-switch budget
PoE-in is not automatically PoE-out
The powered switch must explicitly support the input standard and a standards-based downstream output. Its downstream budget may change with 802.3af, 802.3at, 802.3bt, or DC input, even when the ports look identical.