In BPON and GPON Ethernet frames are encapsulated and transmitted already inside other type of frames. In EPON, however, Ethernet frames are transmitted natively without use of TDM. Technology is shown in Figure 1.
Figure 1. An example of EPON.
ONU buffers allow data transmission without interference in the upstream direction. Data frames are quede and switched into backbone network in the OLT. Switching point is also maintaining priority for different data, based on Ethernet frame priority field.
Figure 2. Ethernet frame, including priority field.
Ethernet frame structure is shown in Figure 2. Payload size of the Ethernet frame is between 40 and 1494 bytes. Destination Address and Source Address are containing unique 48-bit MAC addresses of the receiver and sender devices. The tag control field in the header is defining priority level of the Ethernet frame. The VLAN identifier is associating a subset of participating communication entities.
Testimonials
Lomoveishiy – Finland
I needed those to connect my PC on the third floor to have internet access in that room, and ISP installed their modem on the first floor only. After dropping fiber patch cables, plugged in all cables into these media converters at both sides, and link came up instantly. Was much easier than I thought!
