Broadband fiber access refers to an access bearing method that uses optical fiber as the transmission medium throughout the entire process between the user network interface and the relevant service node interface, or uses optical fiber as the backbone transmission medium and metal wires or wireless as the user terminal transmission medium.
The technologies used in broadband fiber access networks include xPON, MSTP, MSAP, Ethernet, PTN, optical fiber direct connection, etc. OLT, ONT, and ONU in Figure 1 refer to optical line terminals, optical network terminals, and optical network units respectively. They generally refer to central office equipment and user equipment in various technologies, not just xPON technology. As can be seen from Figure 1, the connection from OLT to users belongs to the broadband fiber access network.
ODN refers to the passive optical distribution network composed of optical fiber cables and passive optical components (such as optical connectors and optical plc splitters) between OLT and ONU/ONT. It is mainly composed of optical cable lines in different sections (see ” ODN Optical Distribution Network Structure”). When xPON technology is used, the ODN includes an optical splitter, as shown in Figure 2; when passive wavelength division technology is used, the ODN includes an optical terminal multiplexer OTM or an optical add-drop multiplexer OADM.
Typical applications of broadband fiber access
Broadband fiber access includes typical application types such as FTTH, FTTO, FTTB, FTTC, and FTTCab, commonly known as FTTx.
FTTH refers to optical fiber to the home user, which is an access method that only uses optical fiber transmission media to connect the communication central office and the home. The optical cable to the home is exclusive to a single home.
FTTO refers to optical fiber to the company/office, which is an access method that only uses optical fiber transmission media to connect the communication central office and the company or office. The optical cable to the home is exclusive to a single company or office user, and the equipment and network after the ONT are managed by the user. People often confuse FTTH and FTTO. Please pay attention to the conceptual differences.
FTTB FTTC refers to optical fiber to the building or fiber distribution unit. After the optical fiber reaches the building, the ONU is set at a suitable location and then provides access services to users through metal wire pairs or wireless. Each ONU typically supports ten to one hundred users. The concept of FTTB/C has been basically replaced by FTTB, and Cat5 patch cords are mainly used from ONU to users.
FTTCab refers to fiber to the junction box, and the cable junction box here usually refers to an outdoor cabinet. The ONU is set up in an outdoor cabinet. After the optical cables are laid into the cabinet, access services are provided to users through metal wire pairs. Each ONU typically supports hundreds to thousands of users. Currently, the FTTCab method is basically no longer used.
Although FTTx is translated as “fiber to xx”, its meaning includes not only laying optical fiber to xx location, but also including the setting location of ONU/ONT.
The difference between ONU and ONT is: ONT is a type of ONU. ONU is usually shared by multiple users, while ONT is exclusive to a single user; therefore, user equipment in FTTH and FTTO applications is usually represented by ONT, FTTB and FTTCab In applications, user-side equipment is represented by ONU.
The relationship between broadband fiber access network and other networks
In Figure 1, the upper network of the broadband fiber access network is the core network. Isn’t it the transport network?
From a business perspective, communication networks are usually divided into core networks and access networks. The transport network is the connection network between the core network and the access network. The metropolitan transport network is generally divided into core layer, aggregation layer and access layer, but the access layer of the transport network and the broadband fiber access network do not have the same meaning.
Three Common FTTX Solutions
- Point-to-point FTTx solution
Point-to-point direct fiber connections have the advantages of easy management, no complex uplink synchronization technology and automatic terminal identification. In addition, the entire upstream bandwidth can be used as a terminal, which is very conducive to bandwidth expansion. But these advantages cannot match its disadvantages in terms of devices and device costs.
Ethernet + media converter is a transitional point-to-point FTTH solution. The initial solution uses a media converter (MC) to convert electrical signals into optical signals for long-distance transmission. Media converter is a simple photoelectric / electro-optical converter, it does not process signal packets, so it incurs costs.
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The advantage of this solution is that you only need to add MC to the existing electrical Ethernet equipment. There is no need to replace the interruption that supports fiber optic transmission. You only need to add MC, so that users can reduce the cost of upgrades. It is a network solution during the transition period of point-to-point FTTH solutions. Because its technical architecture is quite simple, its price is low, and it is directly integrated with the Ethernet network, it once became the mainstream of FTTH in Japan.
- Point-to-multipoint FTTx solution
In the optical access network, if the optical distribution network (ODN) is composed entirely of passive components and does not include any active nodes, then this optical access network is PON. The PON architecture mainly broadcasts the optical signals downstream from the optical fiber line terminal equipment OLT to each user terminal equipment ONU/T through an optical fiber and the passive device splitter. In this way, It greatly reduces the cost of network equipment room and equipment maintenance, and also saves a lot of construction costs such as optical cable resources. PON has therefore become a new popular technology for FTTH.
- PON access network technology
As an access network technology, PON is positioned in what is often called the “last mile”, that is, a solution between service providers, telecom offices, and business users or home users.
With more and more broadband applications, especially the rise of video and end-to-end applications, people’s demand for bandwidth is getting stronger and stronger. In North America, the bandwidth demand of each user will reach 20-50Mb/s in 5 years, and will reach 70Mb/s in 10 years. Under such high bandwidth requirements, traditional technologies will not be able to cope, but PON technology can show its talents.
FAQ
What does FTTH mean?
FTTH is short for fiber to the home. It is a transmission method of optical fiber communication. Specifically, FTTH refers to installing optical network units (ONUs) at home users or enterprise users. It is the optical access network application type closest to users in the optical access series except FTTD (fiber to the desktop). The notable technical feature of FTTH is that it not only provides greater bandwidth, but also enhances the network’s transparency in data formats, rates, wavelengths and protocols, relaxes requirements on environmental conditions and power supply, and simplifies maintenance and installation. PON technology has become a hot topic for global broadband operators and is considered to be one of the best technical solutions for realizing.
What is the difference between FTTH and FTTR?
FTTH: Fiber to the home, which is a transmission method of optical fiber communication. Specifically, FTTH refers to the installation of optical network units (ONUs) for home users or enterprise users.
FTTR: Fiber to the room, it is a new internal network technology based on fiber optic communication. At present, fiber-to-the-home is usually completed by the operator’s optical fiber to the home, excluding indoor networks.
What is difference between fiber and FTTH?
Fiber is optical fiber, it is an item made of glass or plastic that can be used as a light transmission tool. FTTH is a fiber optic transmission method. It is quite different.
What is FTTP vs FTTH?
FTTH is fibre to the home; FTTP is fibre to the premises, similar like FTTB. FTTH is more close the home end users from the word meaning, the fiber access user is different, fiber to the home is individual home subscribers, but fttb end user maybe company with many end users.
What is the disadvantage of FTTH?
ased on the MAC speed limit mode, the delay will increase when the broadband is full.
In terms of speed, FTTH provides a maximum of 4M uplink and 100M downlink, which are unequal lines.
What is FAT?
FAT is fiber access terminal. Yingda FAT boxes are named after this. For example: FAT-8A, that means this box is used in fiber access terminal, and it mainly 8pcs access to end users.
Is there coaxial cable during FTTx network?
Yes, all FTTx network still need coaxial ables, due to the end equipment like PC or tablet or ONU still with coaxial interface, not optical interfaces. Network components that define the optical loop are known as Optical Line Termination or OLT at the operator’s side and Optical Network Terminal or ONT at the client’s side. The point where the fibre optics ends, that is, where the ONT is located, determines the kind of optical access network, resulting in the following denominations:
Because the transmission through the fibre is bi-directional, each direction uses a different wavelength to avoid interference.
How does an access point work?
An access point is a device that creates a wireless local area network, or WLAN, usually in an office or large building. An access point connects to a wired router, switch, or hub via an Ethernet cable, and projects a Wi-Fi signal to a designated area.
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