What PON is? Simply speaking, PON is a passive fiber network composed of the following three parts:

1. OLT (Optical Line Terminal)

2. ODN (Optical Distribution Network)

3. ONT (Optical Network Terminal) or ONU (Optical Network Unit)

They are collectively referred to as access network equipment and are important equipment for FTTH fiber home network.

The simple explanation is from the telecommunications area backbone network access to the community or street room OLT equipment. Then OLT is connected to ODN optical divider for proportional allocation.

Once the ODN light is separated, it can be directly connected to the ONT device or ONU device. ONT is also known as the light cat, and ONU is generally used for enterprise access, and it is also very expensive.

These are the basic framework of FTTH network, and GPON and EPON are equivalent to interface protocol. GPON is superior to EPON in bandwidth.

EPON provides fixed upstream and downstream 1.25Gbps, using 8b / 10b line code, and the actual rate is 1Gbps.

GPON supports a variety of rate grades and can support the asymmetric rate of upstream and downstream. The downstream rate can be 2.5Gbps or 1.25Gbps, while the upstream rate can be 1.25Gbps or 622Mbps. The upstream and downstream rate can be determined according to the actual demand.

In addition, both G and E support single-mode transmission. Traditional optical fiber requires two optical fibers to solve the problem of up-down transmission. PON can transmit two-way signals by single core, for example, downlink 1490nm to transmit voice and data, and 1550nm to transmit video signal. The uplink signal is 130 nm, all in the same fiber. This in turn reduces the cost of wiring and lighting modules.

Then, the upgraded XGPON and 10GEPON based on GPON and EPON are derived. These two new interface protocols are suitable for 10Gb network deployment.

At present, 99% of domestic users use EPON or GPON naked cats, and only a very few users use 10GEPON naked cats.

10GEPON supports both symmetric and asymmetric modes. Symmetry refers to the upstream and downstream bandwidth of 10Gbps, while asymmetry refers to the downstream bandwidth of 10Gbps and the upstream bandwidth of 1Gbps.

XGPON also supports both symmetric and asymmetric modes. Symmetry is called XGPON2 upstream and downstream symmetric bandwidth 10Gbps, while asymmetry is called XGPON1 downstream bandwidth 10Gbps and XGPON1 upstream bandwidth 2.5gbps. In terms of asymmetric standards, XGPON will be more advantageous than 10GEPON.