ATM-PON leads man broadband access

The urgent needs for high-speed data services and the future needs for video services provide unprecedented opportunities for broadband access, and various broadband access technologies are emerging. The ATM-based PON combines the capabilities that ATM is suitable for providing comprehensive broadband services. The upstream and downstream communication bandwidths can reach 155 Mbps. The bandwidth available to each user can be flexibly divided based on the protocol for sharing.

At present, it mainly includes the access technology xDSL based on twisted pair transmission), and the Access Technology Based on Coaxial Cable and fiber-optic hybrid transmission) ethernet Access Technology Based on Optical Fiber and Category 5 lines, wireless transmission-Based Access Technology (MMDS, LMDS, etc) and the Access Technology Based on Optical Fiber Transmission mainly includes ATM-PON technology, SDH-based Active optical access ). These broadband access technologies have different priorities and have different application scenarios and life cycles. The access network technology is very different from the backbone network technology. It must be directly oriented to a variety of user groups with very different needs, especially when the economic development level in China is very unbalanced ), this determines that the access network technology is diversified, and it is impossible for a technology to take over the world.

In order to make a clearer comparison of various broadband technologies, the following table lists their situations in various aspects as shown in Table 1 ).

This article analyzes and compares various broadband access technologies from the perspectives of service support capabilities, costs, technical features and maturity, applicable user groups, maintainability, and scalability, and how to work with the main Metro segments, based on this, we will discuss the broadband access solutions applicable to broadband MAN for various user needs.

Applicable to man access segments

Fiber-to-user is the ultimate goal of broadband access, and the closer the fiber-to-user is, the closer the end goal is. Currently, optical fiber access is mainly applied to the main layer and access layer of the Metropolitan Area Network for business transmission multiplexing and access) or directly to large and medium-sized enterprise users. Fiber access mainly includes SDH-based Active optical access and ATM-based passive optical access-ATM-PON. Although SDH technology is also transitioning from mature transmission technology to access technology to provide interfaces such as DDN, FR, and IP, due to the limited number of users connected due to the time division multiplexing mechanism, the overall cost-effectiveness is greatly reduced, and is generally only applicable to users of large enterprises. The technical characteristics of ATM-PON make it suitable for the access section of man. ATM-PON technology features are as follows: 1. ATM-PON adopts the light distribution network (ODN) without source optical splitter, and each ONU shares the ODN and local device-OLT, and there is no active device between ONU and OLT, which facilitates maintenance and operation, therefore, not only the potential cost is low, but also the reliability is high; 2. the technical advantages of PON are that the transparency of pure media networks to multiplexing technology and wavelength is conducive to the development of business or technology in the future. 3. ATM-based PON combined with centralized ATM and statistical multiplexing technology to make the network of shared media more economical and reasonable; 4. the high-speed grouping technology and QoS Management of ATM have mature technical guarantees for supporting multi-rate access requirements, including IP services; 5. the ATM-PON access technology can communicate well with the main CIDR blocks of the ATM man. However, ATM-PON technology maturity is far inferior to SDH technology, there is no scale before the application of high costs, currently applicable to large and medium enterprises and SOHO, ordinary residents are suitable for the use of ATM-PON + ADSL.

Connect to the Trunk Segment

In addition to the above costs, technical maturity, applicable user groups, maintainability, and scalability, the broadband access technology should also focus on the connection between the access section and the main segment in the broadband Metropolitan Area Network.

Which technology should be used to form the main layer of the broadband MAN? It should be determined by factors such as technical characteristics, technical maturity, scalability, and business characteristics that will be open on the network. If, due to the current operating mechanism and other reasons, it may be unrealistic to implement integrated access at the Broadband Metropolitan Area Network access layer, the main part of the metropolitan area network is used as a comprehensive platform for providing data, voice, and video services, it is both realistic and necessary. If the IP technology is used to build a broadband MAN, it will not be able to provide users with voice access, bandwidth rental and other services, and cannot truly achieve a single network to meet various personalized needs of users, thus improving market competitiveness; by using the ATM technology, the advantages of the ATM technology can be used to provide users with existing and possible future services.
Table 1 Comparison of various Broadband Access Technologies

In the near future, the broadband man will mainly provide Internet Data Services. Most of the data services will flow beyond the man. Therefore, the function of the broadband MAN is mainly to reuse services. The main advantage of IP technology-routing and fast exchange, which cannot be used within the metropolitan area network; on the contrary, broadband man must take advantage of the technical advantages of ATM-Statistics reuse of various services, including Internet services. Some people have made theoretical analysis. A 622 Mbit/s ATMVP Service supports more than a 2.5 Gbit/s/sSDH ring, from which we can see the advantages of ATM statistics reuse. From the perspective of development trends, telecom operations should be tailored to a variety of users. If a business can have a variety of service categories and price options, it will undoubtedly attract users at different levels. Because IP addresses can only provide the best-effort service and pay by traffic, SDH can only provide fully guaranteed services and charge on time. However, ATM can provide multiple service categories, such as CBR, VBR, ABR, and UBR, users can choose a combination of time length, port, traffic, average traffic, and other billing methods according to their own circumstances. In addition, it is recognized by industry authorities that MPLS technology combines the advantages of ATM technology and IP technology and is the future development direction. However, MPLS technology is easy to implement on an ATM network. In conclusion, from the perspective of technical rationality and future development, ATM technology should be the best choice. However, with ATM technology, the current investment is larger than IP technology. In the long run, the current large investment is in exchange for small investment and more users in operation management and upgrading.

In this way, if the main broadband MAN using ATM technology, then ATM-PON access means and its convergence, in the technology is the most reasonable. In fact, ATM networks have been set up in economically developed regions such as Beijing, Shanghai, and Guangdong in China. It is also necessary to make full use of this huge resource.

Summary

Based on factors such as service support capability, cost, technical features and maturity, applicable user groups, maintainability, scalability, and how to integrate with the main Metro segment, enterprises and enterprises can, ATM-PON is one of the best access technology options for broadband MAN using ATM technology. For enterprises/residents who have created five kinds of lines, FTTx + LAN is used in the access layer, using the ATM + Ethernet switch solution on the trunk layer is advantageous. The most prominent advantage is the low cost, for non-cloth 5 class lines of enterprises and residential users ATM-PON + ADSL access mode is also very competitive, especially in the manageability and good upgradeability.