The Performance Metrics And Relationship Of High-Speed Access Network

With the continuous development of Internet technology, VoIP, online video and other multimedia services are delivering constantly, which requires higher speed and wider bandwidth of the network. As the "last mile" of the network, access network has become the bottleneck of the entire network system. Therefore, how to develop the broadband access network has become one of the most important issues for operators.Among current major broadband access technologies, Ethernet access technology has a higher access speed, and correspond with situation of the concentration of the customer in our country. It's a typical access network and has board space for development.So this paper focuses on the performance of Ethernet optical access network.There are many characteristics to indicate error such as bit error, byte error, frame error and packet loss.The past studies of packet loss focused on packet loss detection, lost packet processing, the reasons of packet loss, and so on.While the researches of bit error focused on error monitoring, monitoring methods, error locating as well as the estimation of bit error rate.However, studies on their relationship is lacking.So this paper investigated the frame error on the data link layer in high-speed optical access network, including the representation form, influencing factors and distribution characteristics of frame error and byte error, and the relationship between them.The Gigabit Ethernet test bed was chose as the main test environment which established including a network tester, a variable optical attenuator, optical link and a purpose-built tool which allows us to examine errors on a per-octet basis.The network tester serves as both the generator and the receiver equipment. It can freely create frame streams, fill the payload of frames and set the numbers of frames.It also can capture error frame from the received frames by setting capture parameters.Data process module is a purpose-built tool which allows us to examine and process the error frames from the network tester. Error frame is compared to the original frame octet-by-octet and if they differ, the location will be recorded.The numbers of error octets and error frames will be calculated in every second.SPSS and MATLAB are used to analyze the data provided by the data process module, and finally the network performance and their relationships are discussed and analyzed by statistical analytical methods such as the non-parametric estimation.This paper mainly describes five aspects of frame error and byte error, including:the impacts and representation forms of frame error, the distribution characteristics of frame error and byte error and the relationship between the distribution.The extra-bit frame and bit error are the two main reasons resulting in frame error. The extra-bit frame accounts different proportion in the whole error frames when the frame length is different or in the different attenuation condition.Increasing attenuation in the network brings in larger proportion of extra-bit frame.Longer frame length in the traffic results in the lower proportion the extra-bit frame.We find that regardless of the extra-bit frame effect, the frame error and byte error obey the Poisson distribution in the different parameters,From the research results, we can get the conclusion listed as follows:1,Bit error is the main reason resulting in frame error when the network in the low attenuation,while the extra-bit frame and bit error are the two main forms of frame error in the higher attenuation.2, The frame which is filled with different bytes has different probability tending to be error at the same condition.3,The frame error and byte error obey the Poisson distribution in the low attenuation, while the distribution of error frame and error byte are affected by the length of the frames transmitted in the high attenuation.