PON is a passive optical fiber network, which consists of three parts: OLT (optical line terminal), ODN (optical distribution network), ONT (optical network terminal) / ONU (optical network unit). These three parts are important equipment for building FTTH Optical Fiber home network. A simple explanation is to connect OLT equipment in the computer room of the community or street from the backbone network in the telecommunication area, and then connect OLT to ODN optical distribution equipment for proportional distribution. After ODN optical distribution, it can be directly connected to ont equipment or ONU equipment.
GPON and EPON are equivalent to interface protocol, GPON is superior to EPON in bandwidth,EPON provides fixed uplink and downlink of 1.25gbps, with 8B / 10B line coding, and the actual speed is 1Gbps.
GPON supports a variety of rate levels, which can support the uplink and downlink asymmetric rate. The downlink rate is 2.5Gbps or 1.25gbps, and the uplink rate is 1.25gbps or 622Mbps. The uplink and downlink rate is determined according to the actual demand, and the corresponding optical module is selected to improve the rate price ratio of optical devices.
Both of them support single-mode transmission. Traditional optical fiber needs two optical fibers to solve the problem of uplink and downlink. PON can rely on a single core to transmit two-way signals, such as downlink 1490nm to transmit voice and data, 1550nm to transmit video signals. The uplink signal is 1310nm, all in the same optical fiber. This reduces the cost of wiring and optical modules.The upgraded versions of XGPON and 10gepon are derived based on GPON and EPON. These two new interface protocols are applicable to 10g network deployment. At present, 99% of domestic users use EPON or GPON optical cat, and only a very small number of users use 10gepon optical cat.10gepon supports both symmetric and asymmetric modes. Symmetric means 10Gbps uplink and downlink symmetric bandwidth, asymmetric means 10Gbps downlink and 1Gbps uplink.XGPON also supports both symmetric and asymmetric modes. The symmetric mode is called xGPON2 uplink and downlink symmetric bandwidth 10Gbps, while the asymmetric mode is called xGPON1 downlink 10Gbps and uplink 2.5Gbps.According to the asymmetric standard, XGPON will have more advantages than 10gepon.
