FTTH (fiber to the home) is a foreign language abbreviation for fiber direct to home, and the Chinese abbreviation is fiber to home. Specifically, FTTH refers to the installation of optical network unit (ONU) at home or enterprise users, and it is the type of optical access network application closest to users except FTTD (fiber to desktop) in the optical access series. Optical fiber to the home is the shining star of the next generation access network technology, which provides an ideal platform for ultra-high-speed access technology.
There are two main types of infrastructure in FTTH deployment: active Ethernet and passive optical network. Active Ethernet is a point-to-point network, while passive optical network is a point-to-multipoint network. These two kinds of infrastructure have their own advantages and disadvantages, and when choosing, we should consider factors such as network business type, cost, future technology upgrade and so on.
In the active optical network (Active Optical Network,AON), ONU devices are connected in series in the optical fiber network. The signal received by each ONU is the signal after the optical-electro-optical conversion of the superior ONU. Because there is a dedicated optical fiber line between each terminal and the office, the management and maintenance of the line in active Ethernet is very simple. The advantages of active FTTH network architecture are: network power budget and troubleshooting are easy to estimate, data transmission is more secure, and so on.
The core components of peer-to-peer network are core switch, aggregation switch and optical network terminal (ONT,optical network terminal).
Among them, the core switch is a kind of high-capacity Ethernet switch, which transmits the data, video and audio signals of the service provider to the users in the access network through the MPLS-based metropolitan area network or regional network.
The aggregation switch can be placed not only at the central office, but also at the indoor entrance or outdoor according to the environmental requirements of the network provider. It transmits data to multiple optical network terminals (ONT) at a transmission rate of 1 Mb/s-100 Mb/s.
The 10G FTTH EPON technology, the industrial chain has been mature, began to be used by operators for FTTB/FTTH scale deployment, the cost is also decreasing year by year.
Passive optical network (Passive optical network,PON), also known as passive optical fiber network, is a kind of optical fiber communication network, which is characterized by signal processing without power supply, just like a mirror at home, which can reflect images without electricity. Except that the terminal equipment needs electricity, the nodes between them are composed of delicate and compact optical fiber components.
It is a kind of pure medium network, which avoids the electromagnetic interference and lightning influence of external equipment, reduces the failure rate of lines and external equipment, improves the reliability of the system, and saves maintenance costs.
Optical line terminal (OLT,optical line terminal) is an important component in passive optical network, which is usually located in the local exchange.
Similar to active Ethernet, the optical network terminal (ONT) in the passive optical network is also placed at the user end, except that the optical network terminal (ONT) is connected with the optical line terminal (OLT) through optical fiber and passive optical devices (optical splitters).
Optical network terminals (ONT) can be placed indoors or on the side of the street.