Optical broadband access will become the ultimate mode of fixed broadband access, which has become the consensus of the industry. However, the optical fiber broadband access when it can become a mainstream form of broadband access? Currently can not get a clear timetable.
XDSL over copper, the bandwidth bottleneck faced
Just go to work Monday morning, city maintenance workers Lee Board received from the maintenance center to transfer to the complaint No. 10,000 single, who lives north of the city were also complaints that embittered residents of the old liberated areas, and complained that broadband Internet access faster and faster.
Recently, Lee works department where a lot of similar complaints have been received one. As the old liberated areas north of the city's lines have been some years, and the line length is 4 km, the original opening of ADSL has been some reluctance, the bandwidth only to 512K. Recent rain and urban transformation, affected by line quality, ADSL speed is decreased. In order to develop more broadband users and increase the attractiveness of broadband networks, the bureau is to promote experimental and IPTV services, the district is also within the scope of the pilot. But now would like to directly increase the rate of ADSL have been helpless.
To focus on the current central office building that model, ADSL's subscriber line is relatively long, generally more than 3Km, taking into account such issues as the quality of the actual lines, it is difficult to further increase the bandwidth of ADSL users, line rate as the development of new users and increase new business bottlenecks. In order to provide high-bandwidth tripleplay value-added services, broadband speed is the choice of operators to be. For the DSL line, the one of the most important feature is the closer the higher the bandwidth can be provided. Therefore, in order to meet the high bandwidth to carry out tripleplay business needs, we must make broadband access equipment (DSLAM) is shifted from the central office Zhubu closer to users in the region, which became the persistence of DSL access mode the only option.
Light has become an inevitable choice of Copper
To shorten the distance between copper, fiber optic can only be extended further to the user side, the process of promoting the construction of FTTx. According to the engineering model of copper wire PSTN, a user section of copper wire into trunk, feeder section, sub-segments, household segment. In the broadband access equipment to achieve the user from the central office down the process of the bandwidth speed is broadband access equipment from the trunk section of the feeder segment, sub-segment and-home segment of the migration process is to gradually close to the user optical access, light into the Copper refund process.
Currently, FTTx construction mode FTTC (Fibretothecurb), FTTB (Fibretothebuilding) and FTTH (Fibretothehome). In the FTTC, FTTB mode, the final-home technology, including ADSL, ADSL2 +, VDSL, VDSL2, and LAN. According to the distance optical fiber to the user, each user's bandwidth requirements, as well as the existing Line Resource for operation and maintenance costs of different considerations, 闇? choose the right of the optical fiber technology and-home technology, to deploy the appropriate fiber-optic broadband access Wangluo.
So remote broadband access equipment to disappear gradually down along the course, is the fiber-optic broadband access from the start to the evolution of the mainstream. According to the current status of broadband access, carrier deployment pipeline, combined with the bandwidth speed of the process, you can find a suitable building mode optical fiber broadband access.
For different construction mode, you need the number of users under the node, the user bandwidth, pipeline resources, equipment, construction costs, operation and maintenance costs will be different, use of P2P and P2MP PON-based fiber optic technology, as well as the appropriate DSL and Ethernet households line technology. The so-called "right is the best." Let's look at each of Copper-ray patterns of the four main scenarios.
Photo of Copper 4 Steps
FTTC + xDSL mode
FTTC + xDSL broadband access equipment model is the first step down that migrate from the trunk section of feeder segment. Broadband access equipment in the feeder section of the traditional copper distribution frame location, usually in the street or residential room. Feeder section of the twisted pair from the MDF to the user is generally less than 2Km, according to the different user density, coverage is generally the number of users is about 100 ~ 500.
FTTC + xDSL mode is characterized by the number of low demand of optical fiber, optical cable deployment is easy, full use of the sub-existing copper line Zi Yuan, the entire building model and the central office equipment, broadband access methods are very similar, project implementation is also relatively simple at the same time to meet the basic tripleplay business needs.
FTTC + xDSL mode is particularly suitable for relatively good quality copper wire, the user bandwidth requirements are not too high, operators, construction costs are low, not high maintenance costs, and achieved a good balance. This is also the traditional operators to provide higher bandwidth broadband access to the mainstream building model.
FTTB + xDSL mode
FTTB + xDSL broadband access equipment model is the second step down, move to sub-paragraph from the feeder line. Broadband access equipment in the traditional copper sub-segments of the sub-junction box location, usually in the building side or multi-user centralized office. To the user's distance from the building can be divided into two situations: First, less than 1000m, covering the number of users is about 50 ~ 200; one less than 500m, covering the number of users around the 20-100.
The case for less than 1000m, you can access using ADSL2 + technology to take full advantage of the characteristics of ADSL2 +, the highest bandwidth of about 25M. The situation is less than 500m, you can access using VDSL2 technology to take full advantage of the characteristics of VDSL2, the highest bandwidth of 50M ~ 100M.
Building in the FTTB + xDSL mode, which uplink optical fiber access technology used and what kind of xDSL access technologies, requires from the user area density, the number of users per node, the maximum guaranteed bandwidth of each user, each user's maximum bandwidth to integrated planning. When the number of users per node, the less the bandwidth of each user to ensure the smaller, more focused on the node, using P2MP fiber optic technology the higher the value, otherwise use P2P fiber optic technology is better. When the user wants to get the maximum bandwidth of greater than 25M, it was much closer, VDSL2 access technology is more appropriate; when the user wants to access the bandwidth is not greater than 25M, using ADSL2 + technology is the most cost-effective.
FTTB + xDSL mode is evolution to FTTH most complex model, copper layout of the user is closely related to the actual situation must be taken into account. If the access module is too small, the sharp increase in the total number of nodes, management and maintenance to bring a very big problem; if the access module is too large may cause the user line is too long, can not provide sufficiently high bandwidth, can not meet the new business needs. Therefore, operators need to OPEX and operational capacity to do balancing selection, equipment providers need to lower OPEX's FTTB solutions together to achieve the smooth evolution to FTTH.
FTTB + LAN Model
FTTB + LAN Ethernet access building mode is actually the construction of models. Relative to the FTTB + xDSL building model, and its greatest feature is the ability to offer symmetrical broadband access for business customers and large upstream bandwidth requirements of individual users.
FTTB + LAN model can provide users with broadband access 100M or GE, the number of users by adjusting the node and PON in the splitting ratio, and can flexibly provide users with the appropriate assurance of broadband, both to provide users with a traditional tripleplay business, but also can provide enough bandwidth to meet the needs of P2P and other new business. However, this model will be FTTB + VDSL2 serious challenges, especially mature VDSL2 applications, due to the VDSL2 bandwidth and flexibility of distance, LAN access may be replaced by VDSL access.
FTTH model
Optical fiber to the home or office is the ultimate mode fiber access is to provide a variety of high bandwidth broadband users an ideal way of value-added services.
P2P and P2MP FTTH are two ways. When the user rather scattered, each user needs to ensure broadband relatively large, such as the 100M or so, you can use P2P fiber access technology. P2P approach to meet high-value customers with high bandwidth requirements, and can provide adequate security, high bandwidth, high-value commercial customers an ideal choice.
Because of the almost unlimited ability to support operations and maintenance costs low ODN, FTTH construction mode as operators most looking forward to building models. But now direct the deployment of FTTH, there are still many problems. First of all, PON-based broadband access equipment is still the pilot phase, there is no scale deployment capabilities, limited the size of FTTH promotion. Followed by the deployment of fiber-optic project, particularly project-home section of fiber deployment and labor costs has seriously affected the implementation of FTTH. Only when the FTTH optical access equipment, technology and engineering technology is breakthrough, FTTH for CAPEX decreased to levels comparable with DSL, FTTH broadband access can become a mainstream construction mode.
Still a gradual withdrawal of light into the copper
According to consulting firm Infonetics survey, FTTC, FTTB is the operator of the mainstream choices, only some of the operators in the new regional select FTTH. NTT FTTH promotion as the most active operator, is still in its construction plan, 30% of users use FTTB + VDSL2 construction methods.
Considering technical, CAPEX, OPEX and operational capacity at the request of new residential and new-home building and other green areas without copper, when the user demand for higher bandwidth, wish to adopt more business, recommend optical fiber directly into the The one-step approach to achieve the ultimate broadband access mode - fiber to the home. In other cases, are used FTTB + xDSL mode. In the subscriber line is less than 500m, the use of VDSL2 technology to the highest users of bandwidth to meet future business needs. If using ADSL2 + technology. The highest bandwidth at the same time, reducing CAPEX, to achieve the most cost-effective program. This model will not only be able to meet the tripleplay business needs, but also expand to meet future bandwidth demands, while taking advantage of the stock of copper resources, to obtain the optimal input-output ratio.
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