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Fiber broadband common way FTTH and FTTB

Optical fiber broadband is to convert the data to be transmitted from electrical signals to optical signals for communication.

Optical cats are installed at both ends of the optical fiber for signal conversion.

Optical fiber is the most ideal among various transmission media in broadband network. It is characterized by large transmission capacity, good transmission quality, low loss and long relay distance.

Optical fiber access can ensure to provide users with high-speed bandwidth of 10Mbps, 100Mbps, and 1000Mbps, and can be directly connected to CHINANET backbone nodes.

The following introduces the two most commonly used home optical fiber broadband access methods: FTTH and FTTB

  1. FTTH is the foreign language abbreviation of fiber optic direct to the home, which means fiber to the home in Chinese

Refers to the direct installation of the optical network unit (ONU) at the home user or business user (where the user needs it).


FTTH fiber to the home

  1. Significant technical characteristics of FTTH: not only provide greater bandwidth, but also enhance the transparency of the network to data format, rate, wavelength and protocol, relax the requirements for environmental conditions and power supply, and achieve faster Internet access and better network quality Stable, online high-definition video, Internet TV, high-speed download, large-scale online games and other network applications are more powerful.
  2. Users can use telephone, broadband, IPTV and other services through one optical fiber, but when installing broadband, they need to install ONU equipment provided by the operator (that is, optical modem, a kind of photoelectric conversion equipment), which simplifies maintenance and installation.
  3. The home broadband installed now is all connected in this way. On the basis of maintaining the user’s existing communication services, the optical fiber line is directly connected to the user’s home, replacing the original cable line, and the communication capability and quality are greatly improved. After the optical fiber is directly connected to the home, the optical modem is used to convert the “photoelectric” signal, and the exclusive broadband has the advantages of large capacity, wide frequency bandwidth, and more stability. The access band basically starts at 100M, which is our main broadband access at present. Way.
  4. The advantages of FTTH are mainly 5 points:

(1), it is a passive network, from the central office to the user, the middle can basically be passive;

(2) Its bandwidth is relatively wide, and its long distance is just in line with the large-scale application methods of operators;

(3) Because it is a service carried on optical fiber, there is no problem;

(4) Because of its wide bandwidth, the supported protocols are more flexible;

(5), with the development of technology, including point-to-point, 1.25G and FTTH methods have developed relatively complete functions.


Diagram of home broadband equipment after FTTH access


  1. FTTB+LAN (FTTB for short): it is the optical cable to the corridor or to the building, that is, the optical fiber to the building

It is a broadband access method based on optimized high-speed optical fiber LAN technology. It uses optical fiber to the building and network cable to the home to realize broadband access for users. We call it FTTB+LAN broadband access network (FTTB for short).


FTTB fiber to the building mode

  1. After the optical fiber is connected to the building, it is connected to the photoelectric conversion equipment deployed by the operator in advance: ONU (Daguangmao). Users in the building newly install broadband, and need to connect the computer, router, etc. in the user’s room with a network cable from the Daguangmao equipment. Equipment, hotels and dormitories often use this method.
  2. It uses network cables instead of optical fiber to enter the home, that is to say, the photoelectric conversion equipment of FTTB is not installed in the user’s home.
  3. Since FTTB is completely like a local area network in the Internet, dialing is not required to use FTTB. The client only needs to install a network card on the computer, and the user can access the network as long as the computer is turned on.
  4. FTTB adopts dedicated line access, which is easy to install. There is only a difference between fast or slow FTTB Internet access. This is the most reasonable, practical, and most economical and effective broadband access method.
  5. FTTB features: high bandwidth utilization and low investment costs. The network upgrade is convenient, and the existing network investment can be protected to the greatest extent. The bandwidth is shared, and the actual bandwidth available to residents is limited by the number of concurrent users.


After fttb broadband access, the network cable is connected to the router

  1. The difference between FTTH and FTTB

The biggest difference between the two is that FTTH can provide users with higher Internet speed.

  1. FTTH is a user’s exclusive ONU bandwidth. In theory, it can reach Gbit bandwidth without optical splitting; therefore, it is no problem to support a maximum access broadband rate of 1000M.
  2. Since FTTB is an ONU with multiple users, the bandwidth of each user is usually limited, and it will not achieve such a high bandwidth for exclusive use. Of course, if you use it for exclusive use, the bandwidth can also be very high, but since the end uses Category 5 or copper cables, the bandwidth loss will be greater. Users covered by FTTB only support the highest broadband access rate of 100M.
  3. The FTTH access method is better than FTTB. FTTH is the best solution to realize the integration of voice, video and data.
  4. How to identify FTTH and FTTB
  5. The equipment is different: when FTTH is installed, ONU equipment (that is, optical modem) needs to be installed;

FTTB’s ONU equipment (big optical modem) is installed in a box somewhere in the building, and there is no need to install an optical modem in the user’s room.

  1. The home line is different: FTTH is an optical fiber home, users can directly enter the home through an optical fiber, and use the indoor optical modem to convert the signal to the user’s Internet access equipment, and use telephone, broadband, IPTV and other services;

FTTB is the optical cable to the corridor or to the big light modem of the building, and then when the user installs the machine, it is connected to the Internet device in the user’s room through the network cable from the big cat device, so the network cable enters the home in the end.

  1. The most intuitive thing is to look at the optical cat equipment in the corridor.

The FTTH home access method uses a small optical splitter, which is relatively small and is a square box, as shown in the figure


Broadband fiber distribution box

The FTTB home access method uses a large equipment box, which is relatively large, as shown in the figure