摘要
吉林市广电现有的HFC网络已经完成了双向改造,完成了数字电视整体转换工作,吉林市广电根据IP宽带城域网业务的发展和目前网络运营模式的发展趋势,以及未来发展多种业务的需要,提出打造一张可运营、可管理、高性能、具备多种业务综合承载能力的电信级IP网络,是吉林市广电开展全业务运营的关键,也是目前工作的当务之急。为了能够适应今后广电业务的需求、以及企业用户的宽带接入需求,经过多次技术讨论,对接入层的技术采用EPON接入方式是目前最佳的选择。
对吉林市06年新建小区5处试点进行实验,与传统的CM接入方式相比较。经过实验,总结出EPON的优点。论文主要从技术介绍、解决方案、网络安全建设、向IPV6迁移、IP业务发展、宽带接入运营管理等几方面进行论述。随着光纤在城域网乃至接入网主干段的大量应用,符合逻辑的发展趋势是将光纤继续向接入网的配线段和引入线部分延伸,最终实现光纤到家。EPON有望引领FTTx的发展。
At present, broadcasting-television industry is going through the transforming period into digital television. Besides operating the traditional broadcasting-television business, the broadcasting-television operator supplies support for the blending of digital television, voice-communication and broad-band data, etc. which makes people in this field consider it’s a trend to realize the comprehensive operation some day. The general requirement of the blending of the 3 networks, i.e. the computer network, communicating network, broadcasting-television network has been put forward clearly in the eleventh 5-year planning.
In recent years, the next-generation network has been the topics of the broadcasting-television industry. Based on the broadcasting-television’s HFC network, It’s a great challenge and chance that the industry has ever met, i.e. how to implement the network-reform in order to realize the transition to the new generation cable television network(NGCN) smoothly and to develop the brand-new digital television business and gradually the abundant value-added businesses. Under such condition, JILIN BROADCASTING- TELEVISION BUREAU has realized that two-way networks must be reconstructed first in order to realize the blending of“3 networks-into-one”.
Jilin broadcast-television bureau puts forward that to build a tele-communication-grade IP network which is operational, manageable, high- performance and of comprehensive capacity of carrying many businesses is the key for it to develop all businesses, and is also the most important work at present. To realize the network’s two-way reconstruction is a threshold that JILIN BROADCASTING-TELEVISION BUREAU has to go through. The technology types used in the two-way network reconstruction will coexist for some period of time, but the final developing direction is toward IP, access network is the most improved access type and EPON is the best starting point for ether network building.
The essay discusses on a series of technology problems, such as distance-measuring, band-width allocation, clock extraction, synchronize receive, quality of transmition, agitation, safety, etc. in order to find the broad band access way that suits the industry best at present.
The essay also mentions technology introduction, solutions, network safety construction, agitation, change to IPV6. IP business development ,broadband access operation management, etc.
EPON is the newest one among all the PON technologies which was put forward by IEEE 802.3 EFM.EPON is a kind of broad-band access technology based on highspeed Ethernet platform and broadband access technology that can supply all kinds of integrated services, uses point-to-points network structure, no-beginning fibre transmition mode. to supply lots of comprehensive businesses. EPON carries the following characteristics, low-cost, easy-to-maintain, enlarge and grade, supplies very high band-width, services large area, allocates band-width easily.
EPON technology makes use of the Ethernet network access, so develops very quickly in countries and areas where Ethernet is widely used, such as Japan, Korea, Taiwan and Mainland China. In China, cities like Beijing, Shanghai, Guangzhou, Wuhan, Qingdao, Foshan, Shenzhen, Dalian and Hangzhou all have used the Ethernet.
As the wide use of optical fibre in the main part of the long-distance network, the metropolitan area network and the access network, the logical developing trend is to keep on extending the fibre towards the layout and the leadin parts of the access network, and to finally realize“fibre to home”. Hopefully the EPON will lead the development of FTTX.
PON technology is the kind of point-to-points fibre access technology which is newly developed. PON consists of OLT,ONU and ODN. Usually its downlink makes use of the TDM broadcasting way and its uplink uses the TDMA way, what’s more, it can form the network of topology that may be tree, star or bus (tree is the typical one).The substantive characteristics of PON is that ODN consists entirely of apparatus of PON and doesn’t contain any source electron devices. Thus avoids the affection of thunder and magnetic interference from the peripheral equipment, reduces the fault rate of the circuit and the peripheral equipment, predigests the complexity of power supply collocation and network management, enhances the reliability of the system, meanwhile, it saves the maintaining cost. Compared with the point-to-points source optical network, the main characteristics of PON technology is easy-to-maintain, low cost(save the fibre and the interface)and high band-width. Its highly efficient and cost-effective characteristics will make it remain competitive in a long time. PON has long been considered to be the future of access network.
As a new technology, how to enter the market and be accepted by the market rests with many aspects. Strictly speaking, EPON products do not have a standard, besides, the resolvent about some technological difficulties such as ranging, synchronization, etc. and futher lower the cost of unexpected optical devices are all very important.
The other access technologies mentioned in the essay all provide some kind of broadband, but they all bear some limits. EPON system can provide high-quality broadband that access technology such as DSL, LAN, Cable Modem etc. can not provide, which makes it suitable for FTTX mode to access to small and medium-sized or even large-sized commercial clients.
Under current circumstances, EPON technology is more likely enter the market by combing with the other technologies. FTTB/FTTC + DSL,FTTB/FTTC + LAN are all nice choice. DSL and LAN technologies are the two main access ways for broadband in China nowadays, but the distance limits of DSL has made it lose large amount of customers, and the traditional LAN technologies also find it hard to supply and maintain the clients’band-width freely. Making use of the EPON technologies not only can connect directly with the service area through the passive transmission network, then enlarge the DSL and LAN to service the user, but also can centralize the management and allocate the band-width. When integrate the ONU into DSLAM, to use EPON can make DSL break the traditional 1500m distance, then make users increase by 50%,and the scope DSL can reach and its to-be users will increase a lot. EPON can be used to provide the existing cable bandwidth in order to realize the real interactive service, meanwhile lower the construction and operation costs by integrating ONU into CMTS.EPON can also be used to supply the fixed wireless launching tower with bandwidth, the problem that how to integrate the updata to CO will be solved in a better way.
From the operator and service suppliers’point of view, EPON can bring various benefits, which include lower the installation, operation and management cost, increase the ratio of return on investment, get more chance of gaining profit and maintain the competitive advantages for a long time. To choose using the EPON system at the due time under suitable circumstances will be a wise choice, whether for the original operator or for the new operator.
引文
[1]:王胜平 《光纤到楼(FTTB)构建城域双向网络》、《2007 国际有线电视技术研讨会论文集》、2007 年 10 月 31 日-11 月 3 日、第 428 页、第 433 页;
[2]戴卫平 《Cable Modem 与 EPON 宽带接入技术比较》、《有线电视技术》2007 年第 5 期,第 23 页;
[3]:陈雪、 《无源光网络技术》、北京邮电大学出版社、2006 年 1 月第一版、第 19、110 页;
[4]:詹宝容 《EPON 接入技术及其应用》、《有线电视技术》、 2007 年、 第1 期 、 第 32 页;
[5]:张文 《IPTV 技术体系及发展趋势分析》、《有线电视技术》、 2006 年、 第 7 期 、 第 83 页;
[6]:杨光 《IPTV 相关技术及目前承载网问题》、《有线电视技术》、 2006年、 第 5 期 、 第 74 页;
[7]:徐俭 《IPTV 技术简介》、《有线电视技术》、 2005 年、 第 22 期 、 第59 页;
[8]:柏小强 《EPON 技术在有线网络宽带数据业务中的应用》、《中国有线电视》、 2007 年、 第 06 期 、 第 551 页;
[9]:黄万昌 《EPON 技术在有线网络建设中的应用》《、有线电视技术》、 2006年、 第 8 期 、 第 24 页;
[10]:林海平 《浅谈有线电视网络的双向改造》、《2007 国际有线电视技术研讨会论文集》、2007 年 10 月 31 日-11 月 3 日、第 222 页。25
[11]:熊登科 《谈谈 EPON 技术》、《有线电视技术》、 2006 年、 第 4 期 、 第 26 页;
[12]:高宗敏 《EPON 和 EOC 在广电网双向改造中的应用》、2007 年八月、第 45 页。
[13]:编辑部 《关注通信和计算机技术的未来走向》、《现代电视技术》、2007 年、第 7 期、第 13 页。
[14]:Andre Girard 著, 杨柳 译、《FTTxPON 技术与测试》、人民邮电出版社、2007.7、2007 年 7 月第一版、第 8、50、110 页