EPON (Ethernet Passive Fiber Optical Network)
EPON is a combination of several best technologies and network architectures. EPON uses a point-to-multipoint architecture and passive optical fiber transmission to provide multiple services over Ethernet. At present, IP/Ethernet applications account for more than 95% of the entire LAN communication. EPON will become the most effective communication method for connecting the end users of the access network by using the above economical and efficient structure. EPON does not require any complicated protocols, optical signals can be accurately transmitted to end users, and data from end users can be centrally transmitted to the central network. At the physical layer, EPON uses the 1000BASE Ethernet PHY, and at the same time, in the PON transmission mechanism, the newly added MAC control commands are used to control and optimize the bursty data communication and real-time TDM communication between each ONU and the OLT. At the second level of the protocol, EPON uses mature full-duplex Ethernet technology. With TDM, since the ONU sends datagrams in its own time slot, there is no collision and no CDMA/CD is required, so that the bandwidth is fully utilized. In addition, EP0N provides QoS similar to APON by implementing 802.1p in the MAC layer.
A typical Ethernet over PON system consists of an OLT, an ONU, and a POS. The OLT (Optical Line Terminal) is placed in the central equipment room, and the ONU (Optical Network Unit) is placed near or integrated with the network interface unit. POS (Passive Optical Splitter) is a passive optical fiber splitter. It is a passive device that connects the OLT and the ONU. Its function is to distribute downlink data and concentrate uplink data. The OLT is both a switch or router and a multi-service provisioning platform that provides fiber optic interfaces to passive fiber networks. According to the trend of Ethernet to metropolitan area and wide area development, multiple Gbit/s and 10Gbit/s Ethernet interfaces will be provided on the OLT to support WDM transmission. The OLT also supports ATM, FR, and SONET connections at rates such as OC3/12/48/192. If you need to support traditional TDM voice, ordinary telephone line (POTS) and other types of TDM communication (T1/E1) can be multiplexed and connected to the attached interface. In addition to providing network concentration and access functions, the OLT can also target users. Different QoS/SLA requirements for bandwidth allocation, network security, and management configuration. The OLT can be configured with multiple OLTs (Optical Line Cards). The OLC is connected to multiple ONUs through POS. The POS is a simple device. It does not require a power supply and can be placed in an all-weather environment. Generally, the POS split rate is 8, 16 or 32, and can be connected in multiple stages. In EPON, the distance between the OLT and the ONU can be up to 20km. If a fiber amplifier (active repeater) is used, the distance can be extended.
The ONU in EPON adopts the mature and economical Ethernet protocol, and realizes the low-cost Ethernet Layer 2 Layer 3 switching function in the medium bandwidth and high bandwidth ONU. This type of ONU can be cascaded to provide high sharing bandwidth for multiple end users. Because the Ethernet protocol is used, in the process of communication, protocol conversion is no longer needed, and the ONU transparently transmits user data. ONU also supports other traditional TDM protocols without increasing the complexity of design and operation. In higher bandwidth ONUs, a large number of Ethernet interfaces and multiple T1/E1 interfaces will be provided. Of course, for fiber-to-the-home (FTTH) access, the ONU and NIU can be integrated into a simple device that does not require switching functions, allowing end users to be allocated the required bandwidth at a very low cost.
OPTICO COMMUNICATION (www.fiberopticom.com) focuses on the development of fiber optic network communication product lines and provides a comprehensive solution to the fiber connectivity system components. We supply fiber optic components, such as fiber patch cord, fiber pigtail, PLC splitter, fast connector, MTP/MPO, CWDM/DWDM, SFP, FTTH solution, Data center wiring solution, etc. All the products adopt strict quality standards in the production and inspection, ensuring excellent operation performance and good product stability, and safely and reliably ensuring the long-term use of products.
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