Fiber-optic communications (FTTx) has always been regarded as the most promising broadband access method following the DSL broadband access method. Unlike common twisted pair communications, it has a higher operating frequency and greater capacity ( According to the user's need to upgrade to 10-100Mbps exclusive bandwidth), attenuation is less, no strong interference, strong anti-electromagnetic pulse ability, and good confidentiality.
Fiber-optic broadband communications (FTTx) includes multiple access modes, such as common FTTP (FiberToThePremise), FTTB (FiberToTheBuilding), FTTC (FiberToTheCurb), FTTN (Fiber to the Neighborhood, FiberToTheNeighborhood, FTTZ (FiberToTheZone), FTTO (FiberToOffice, FiberToTheOffice), FTTH (Fibre to the Home or Fiber to the Home, FiberToTheHome), etc.
FTTH is the best choice for fiber directly into the home
For many home users, FTTH is the best choice. It can connect optical fibers and optical network units (ONUs) directly to homes. It is a variety of fiber broadband access except FTTD (Fiber to the Desktop, FiberToTheDesk). The type of fiber access that is closest to the user. With the generalization of optical fiber broadband access, it should be noted that the current FTTH broadband access has not simply referred to the fiber to the home. It has been widely referred to as various fiber-to-the-home access modes such as FTTO, FTTD, and FTTN. .
In addition to this, readers should pay attention to the difference between FTTH and common “FTTx+LAN (fiber + LAN)” broadband access solutions. FTTx+LAN is a type of broadband access scheme that uses "optical fiber + category 5 twisted pair method to achieve" 100Mbps to cell or building, 1-10Mbps to home" - intra-cell switch and central office switch and optical network unit (ONU) ) Connected, the use of five types of twisted-pair cabling within the community, the user Internet access rate of up to 1-10Mbps. Unlike FTTH, which is a single-homed, single-family private carrier, the bandwidth of FTTx+LAN is shared by multiple users or homes. When the number of shared users is large, the broadband bandwidth or network speed is difficult to guarantee.
FTTH technical standards
At present, it seems that bandwidth-only ADSL2+ and FTTH have become the mainstream of broadband development in the future. In the FTTH technology, after the APON (ATMPON), there are currently GPON (Gigabit PON) standards developed by the ITU/FSAN, and the two major standards defined by the IEEE802.3ah working group are EPON (EthernetPON).
GPON technology is a new generation of broadband passive optical integrated access standard based on ITU-T G.984.x standard. The available bandwidth is about 1111 Mbit/s. Although the technology is complicated, it has high bandwidth, high efficiency, large coverage, and users. The richness of interfaces and other advantages are considered by some European and American operators as an ideal technology for broadband access network services.
EPON solution has good scalability and can implement a variety of fiber-to-the-home mode
EPON (Ethernet Passive Optical Network) is also a new type of fiber access network technology. The effective uplink transmission total bandwidth is 1000 Mbit/s. It adopts a point-to-multipoint structure and passive optical fiber transmission. It can provide multiple types of services over Ethernet. The service integrates the advantages of PON technology and Ethernet technology. It has features such as low cost, high bandwidth, strong expandability, good compatibility with existing Ethernet, and easy management. It is used in Asia, such as China and Japan. More extensive.
No matter which PON optical fiber system is made up of OLT (Optical Line Terminal), POS (Passive Optical Splitter, Passive Optical Splitter/ Coupler POS), ONU (Optical Network Unit, Optical Network Unit) and its network management system . And these parts are installed by the ISP installer at the time of installation. The home users themselves generally have no conditions to erect themselves.
FTTH deployment plan
In terms of specific functions, the OLT is placed at the central office of the ISP and is responsible for the connection, management, and maintenance of the control channel. The maximum transmission distance between the OLT and the ONU can reach 10-20km or more. The OLT has a ranging function to test the logical distance between each ONU and the OLT, and directs the ONU to adjust its signal transmission delay accordingly. The signals transmitted by the distance ONUs can be accurately multiplexed together at the OLT. The OLT equipment generally also has a bandwidth allocation function. According to the needs of the ONU, the OLT allocates specific bandwidth. In addition, the OLT equipment has a point-to-multipoint hub feature. One ONU can carry 32 ONUs (and can be subsequently expanded). All ONUs under each OLT share the 1G bandwidth through time division multiplexing, that is, each ONU can provide up and down. Lines have a maximum bandwidth of 1 Gbps.
POS passive optical splitters, ie, splitters or splitters, are passive devices connected to the OLT and ONU. Its function is to distribute input (downstream) optical signals to multiple output ports, enabling multiple users to One optical fiber is shared to share the bandwidth; in the upstream direction, multiple ONU optical signals are time division multiplexed into one optical fiber.
ONUs generally have 1 to 32 hundred megabytes, which can connect to various network terminals.
The ONU is a device that is used at the user end to access an end user or a corridor switch. It uses a single optical fiber to multiplex multiple ONU data to one OLT port through a passive optical splitter. Due to the use of a point-to-multipoint tree topology, the investment in aggregation equipment is reduced, and the network hierarchy is also more clear. Most ONUs have certain switch functions. The uplink interface is a PON interface. It is connected to the interface board of the OLT device through a passive optical splitter, and the downlink connects through 1-32 Gigabit Ethernet ports and even Gigabit Ethernet ports. Data devices, such as switches, broadband routers, computers, IP phones, set-top boxes, etc., enable rapid deployment from point to point.
How to network in the family
Generally, FTTH-to-home ONUs will provide at least four 100-megabit RJ45 ports. For home users with four computers that use a wired network card, they can meet the needs of multiple computers in the home to share the Internet. In addition to this, for the FTTH network using dynamic IP, the user can also connect to the switch or wireless AP to expand the wired and wireless network as needed.
The current broadband router can perfectly support the FTTH access scheme
For FTTH terminals that use fixed IP and only provide a 100M RJ45 interface, they can be expanded through a broadband router or a wireless router. In the settings, just in the router's WEB setting interface, find the "WAN port" option, the WAN port connection type is selected as "static IP" mode, and then in the following interface, enter the IP address provided by the ISP, the subnet Masks, gateways, and DNS addresses are fine.
In addition, for users who have purchased broadband routers or wireless routers, they should use them as switches or wireless APs in the FTTH network. The following points must be noted when setting up: Set the routers to be switches or wireless APs to use. Connect the twisted pair plug from the ONU device directly to any interface on the LAN port of the router. On the management page of the router, disable the default DHCP server function. Set the IP address of the router and the ONU device with dynamic IP. For the same network segment.
Since fiber access provides unlimited bandwidth, fiber-to-the-home (FTTH) is known as the "king" of the broadband era and is the ultimate goal of broadband development. After fiber-to-the-home, the user's Internet speed can be significantly increased again, and downloading a 500MB DVD movie can take only a few seconds at the fastest, which is several times faster than the current ADSL solution. With the continuous decrease in the cost of FTTH erection, the light to the home is moving from dream to reality.