Architecture Overview:

Switched Ethernet is a networking technology that allows multiple devices to communicate with each other over a local area network (LAN). It uses switches to forward data packets between devices, enabling efficient and reliable data transmission. Optical-distribution architectures refer to the use of optical fibers for data transmission within the network.

AON (Active Optical Network):
- AON is an optical-distribution architecture that is not essentially switched Ethernet.
- It is a point-to-point architecture where each network device is connected directly to the central office.
- In AON, the central office actively manages the traffic and controls the distribution of data to the appropriate destinations.
- It is commonly used in fiber-to-the-home (FTTH) networks, where each home or building is directly connected to the central office.

PON (Passive Optical Network):
- PON is an optical-distribution architecture that is essentially switched Ethernet.
- It is a point-to-multipoint architecture where multiple devices share the same fiber connection.
- PON uses optical splitters to divide the signal and distribute it to the connected devices.
- In PON, the distribution of data is controlled by the devices themselves, rather than a central office.
- It is commonly used in fiber-to-the-premises (FTTP) networks, where multiple homes or buildings share the same fiber connection.

NON (No Optical Network):
- NON is not a recognized optical-distribution architecture.
- It is not related to switched Ethernet or any other networking technology.

Conclusion:
Among the given options, the optical-distribution architecture that is essentially switched Ethernet is AON. PON is another optical-distribution architecture that is essentially switched Ethernet, but it is not mentioned in the options. AON and PON are both commonly used in fiber optic networks, providing high-speed and reliable data transmission.