The IEEE 802.3at standard, also known as PoE+, supports up to 30 watts of power per port, which is sufficient for the wireless access points that require 25 watts each. The older IEEE 802.3af PoE standard only supports up to 15.4 watts of power per port and would not be able to fully power the access points. The IEEE 802.3bt standard provides even more power than needed, supporting up to 60 or 90 watts per port depending on the type. Therefore, 802.3bt would also support the access points, but it is not the minimum required standard and might be unnecessarily expensive if the extra power is not needed. A non-standard proprietary solution should be avoided due to interoperability issues.