CN100459529C - Time delay characteristic measuring method in data communication network - Google Patents

Time delay characteristic measuring method in data communication network Download PDF

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CN100459529C
CN100459529C CNB2005101028151A CN200510102815A CN100459529C CN 100459529 C CN100459529 C CN 100459529C CN B2005101028151 A CNB2005101028151 A CN B2005101028151A CN 200510102815 A CN200510102815 A CN 200510102815A CN 100459529 C CN100459529 C CN 100459529C
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毕建中
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Huawei Technologies Co Ltd
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Abstract

A method for measuring character of time delay in data communication network includes generating at least one measurement message by sending end and using microcode / hardware to label the first sending time seal on said message then sending them out, separating out said message and labeling the first receiving time seal on them as well as labeling the second sending time seal on separated out message then sending said message back to sending end by receiving end, separating out said message and labeling the second receiving time seal on said message by sending end, calculating out time delay character between sending and receiving ends according to four labeled time seals.

Description

数据通信网络中时延特性的测量方法 The Measurement Method of Delay Characteristic in Data Communication Network

技术领域 technical field

本发明涉及数据通信网络技术,尤指一种数据通信网络中时延特性的测量方法。The invention relates to data communication network technology, in particular to a method for measuring time delay characteristics in a data communication network.

背景技术 Background technique

在数据、语音和视频三网合一的数据通信网络中,语音和视频的数据传输对网络承载提出越来越高的要求,其中时延特性是衡量数据承载网络性能的重要指标。所述时延特性是指与网络中的数据传输时间相关的特性,包括时延(Latency)和时延抖动(Jitter)等指标。时延是指数据包在网络中传递所需的时间;时延抖动是指多个数据包在同一段网络中传输所花费时间的变化。In a data communication network where data, voice, and video are integrated into one network, the data transmission of voice and video puts forward higher and higher requirements for network bearer, and the delay characteristic is an important indicator to measure the performance of the data bearer network. The delay characteristics refer to characteristics related to data transmission time in the network, including indicators such as latency (Latency) and latency jitter (Jitter). Latency refers to the time required for data packets to be transmitted in the network; delay jitter refers to the change in the time it takes for multiple data packets to transmit in the same segment of the network.

时延特性对衡量现有数据承载网络性能具有重要的意义。比如,在下一代语音业务网络中,实时提供时延和时延抖动这两个重要指标,能够为诊断网络故障提供可靠的数据。另外,时延特性还能为用户业务的性能分析提供快速准确的依据。根据在线的时延特性测量结果,能够发现网络性能瓶颈,从而优化运营网络,提高网络的可维护性和可管理性,最终提高客户满意度。在获得时延特性后,能够应用于增强NTP报文处理,从而提高数据网络时间的准确度2~3个数量级。The delay characteristic is of great significance to measure the performance of the existing data bearer network. For example, in the next-generation voice service network, the two important indicators of delay and delay jitter can be provided in real time, which can provide reliable data for diagnosing network faults. In addition, the delay characteristic can also provide a fast and accurate basis for the performance analysis of user services. According to the online delay characteristic measurement results, network performance bottlenecks can be found, thereby optimizing the operating network, improving network maintainability and manageability, and ultimately improving customer satisfaction. After the delay characteristic is obtained, it can be applied to enhance NTP message processing, thereby improving the accuracy of data network time by 2 to 3 orders of magnitude.

基于上述应用,如何在线测量数据包在数据通信网络上的时延特性成为一个需要解决的问题。在实际的网络运营中,由于数据包收发设备在地理位置上可能相距几千公里或更远,故通过实验室的一台测试仪器完成上述测量是不现实的。为此,现有技术中也采用其它的一些切实可行的方法对时延特性进行测量。Based on the above applications, how to measure the delay characteristics of data packets on the data communication network online has become a problem to be solved. In actual network operation, since the data packet sending and receiving devices may be thousands of kilometers or more apart geographically, it is unrealistic to complete the above measurement with a test instrument in the laboratory. For this reason, some other practical methods are also used in the prior art to measure the delay characteristics.

方法一、由全球定位系统(GPS)或者其它能统一全网时间的设备提供精度在μs量级的时钟,使不同地理位置的两台测试仪器的绝对时间误差保持在μs量级,通过记录数据包的发端时间和收端时间,获得数据包在数据通信网络上传输的时延特性。该方法是目前较为通用的一种测量时延特性的方法。Method 1. The global positioning system (GPS) or other equipment that can unify the time of the entire network provides a clock with an accuracy of the order of μs, so that the absolute time error of the two test instruments in different geographical locations is maintained at the order of μs. By recording the data The sending time and receiving time of the packet are used to obtain the delay characteristics of the data packet transmission on the data communication network. This method is a relatively common method for measuring delay characteristics at present.

该方法存在以下缺点:This method has the following disadvantages:

(一)需要使用能提供测量时钟的GPS系统,以及与GPS系统配套使用的报文发生器和接收器。由于GPS系统价格昂贵,故该测量方法成本高,对测量仪器的要求比较苛刻。(1) It is necessary to use a GPS system that can provide a measurement clock, as well as a message generator and receiver used in conjunction with the GPS system. Because the GPS system is expensive, the cost of this measurement method is high, and the requirements for measuring instruments are relatively strict.

(二)需要在被测设备中预留专门的测量端口,通过测量端口发送测量数据,且该测量端口不能用来发送实际的业务数据包,故一方面降低了设备的利用率;另一方面,不能在实际的业务环境下测量业务流的时延特性,属于离线测量。(2) It is necessary to reserve a special measurement port in the device under test to send measurement data through the measurement port, and the measurement port cannot be used to send actual business data packets, so on the one hand, the utilization rate of the device is reduced; on the other hand , the delay characteristic of the service flow cannot be measured in the actual service environment, which belongs to offline measurement.

方法二、通过在网络设备下发通用的诊断命令“ping”,由软件记录数据包的发送和接收时间,从而得到时延特性。Method 2: By issuing a general diagnostic command "ping" to the network device, the software records the sending and receiving time of the data packet, so as to obtain the delay characteristic.

由于该方法的时间记录操作借助于软件实现,故易受软件执行效率、任务调度以及系统中重负载任务等因素的影响,使测量出现很大误差。一般情况下,通过该方法获得的时延特性,在测量精度要求为ms量级的语音承载网络中几乎不可用。Because the time recording operation of this method is realized by means of software, it is easily affected by factors such as software execution efficiency, task scheduling, and heavy-duty tasks in the system, resulting in large errors in measurement. Generally, the time delay characteristics obtained by this method are almost unusable in the voice bearer network where the measurement accuracy is required to be on the order of ms.

发明内容 Contents of the invention

有鉴于此,本发明的主要目的在于提供一种数据通信网络中时延特性的测量方法,控制测量误差,使测量精度达到实际应用的要求。In view of this, the main purpose of the present invention is to provide a method for measuring delay characteristics in a data communication network, which can control measurement errors and make the measurement accuracy meet the requirements of practical applications.

为达到上述目的,本发明的技术方案具体是这样实现的:In order to achieve the above object, the technical solution of the present invention is specifically realized in the following way:

一种数据通信网络中时延特性的测量方法,该方法包括以下步骤:A method for measuring delay characteristics in a data communication network, the method comprising the following steps:

a、发送端在发送数据包到接收端时,生成至少一个测量报文,通过自身的微码/硬件为所生成的测量报文逐个标记第一发送时间戳,并将上述测量报文发出;接收端从接收到的数据包中分离出测量报文,并用自身的微码/硬件为分离出的测量报文逐个标记第一接收时间戳;a. When sending a data packet to the receiving end, the sending end generates at least one measurement message, marks the generated measurement messages one by one with the first sending timestamp through its own microcode/hardware, and sends the above-mentioned measurement message; The receiving end separates the measurement message from the received data packet, and uses its own microcode/hardware to mark the first reception timestamp for the separated measurement message one by one;

b、接收端用自身的微码/硬件为分离出的测量报文逐个标记第二发送时间戳,并通过数据通信网络将上述测量报文发送给发送端;发送端从接收到的数据包中分离出所述测量报文,并用自身的微码/硬件为分离出的测量报文逐个标记第二接收时间戳;b. The receiving end uses its own microcode/hardware to mark the second sending time stamps for the separated measurement messages one by one, and sends the above-mentioned measurement messages to the sending end through the data communication network; Separate the measurement message, and use its own microcode/hardware to mark the second reception timestamp for the separated measurement message one by one;

c1、发送端和/或接收端生成目的地址为自身的自环测量报文,通过微码/硬件为所述自环测量报文标记自环发送时间戳,并将自环测量报文发出;c1. The sending end and/or the receiving end generate a self-loop measurement message whose destination address is itself, mark the self-loop measurement message with a self-loop sending timestamp through microcode/hardware, and send the self-loop measurement message;

c2、发送端和/或接收端从接收到的数据包中分离出所述自环测量报文,并用微码/硬件为分离出的自环测量报文标记自环接收时间戳;c2. The sending end and/or the receiving end separate the self-loop measurement message from the received data packet, and use microcode/hardware to mark the self-loop reception time stamp for the separated self-loop measurement message;

c3、根据发送端和/或接收端的自环接收时间戳和自环发送时间戳计算出额外时延;c3. Calculate the additional delay according to the self-loop receiving time stamp and self-loop sending time stamp of the sending end and/or receiving end;

c、根据测量报文所标记的第一发送时间戳、第一接收时间戳、第二发送时间戳和第二接收时间戳,计算出发送端和接收端之间的时延特性中的时延;将所述时延减去额外时延,获得补偿校正后的时延。c. Calculate the delay in the delay characteristic between the sending end and the receiving end according to the first sending time stamp, first receiving time stamp, second sending time stamp and second receiving time stamp marked in the measurement message ; Subtract the additional time delay from the time delay to obtain the time delay after compensation and correction.

步骤a中生成的测量报文带有测量报文标识;The measurement message generated in step a has a measurement message identifier;

则分离测量报文的方法为:根据测量报文标识,使用流分类匹配方法分离出测量报文。Then, the method for separating the measurement message is: according to the measurement message identifier, the flow classification matching method is used to separate the measurement message.

所述流分类匹配方法采用三态内容寻址存储器实现。The flow classification matching method is realized by using a three-state content addressable memory.

所述时延特性包括时间差,则步骤c还包括计算时延特性中的时间差的方法,为:将每个测量报文的第一接收时间戳加第二发送时间戳之和,减去第一发送时间戳加第二接收时间戳之和,获得的差除以二;再将所有测量报文的计算结果取平均值,得到发送端和接收端的时间差。The delay characteristic includes a time difference, and step c also includes a method for calculating the time difference in the delay characteristic, which is: adding the sum of the first receiving timestamp of each measurement message to the second sending timestamp, and subtracting the first The sum of the sending time stamp plus the second receiving time stamp is divided by two; then the calculation results of all measurement messages are averaged to obtain the time difference between the sending end and the receiving end.

所述时延特性包括时延,则步骤c所述计算发送端和接收端之间的时延特性中的时延的方法为:将每个测量报文的第一接收时间戳加第二接收时间戳之和,减去第一发送时间戳加第二发送时间戳之和,获得的差除以二,得到每个测量报文的时延;再将所有测量报文的时延取平均值,得到发送端和接收端的时延。The delay characteristic includes a delay, and the method for calculating the delay in the delay characteristic between the sending end and the receiving end in step c is: add the first receiving timestamp of each measurement message to the second receiving time stamp The sum of the time stamps, subtract the sum of the first sending time stamp plus the second sending time stamp, and divide the obtained difference by two to get the delay of each measurement message; then average the time delay of all measurement messages , to get the time delay of the sender and receiver.

步骤c3所述计算额外时延的方法为:The method for calculating the additional time delay described in step c3 is:

将发送端的自环接收时间戳减去自环发送时间戳,获得额外时延;Subtract the self-loop sending timestamp from the self-loop receiving timestamp of the sender to obtain additional delay;

或者,将接收端的自环接收时间戳减去自环发送时间戳,获得额外时延;Or, subtract the self-loop sending timestamp from the self-loop receiving timestamp of the receiving end to obtain additional delay;

或者,将发送端的自环接收时间戳减去自环发送时间戳获得的第一额外时延,和接收端的自环接收时间戳减去自环发送时间戳获得的第二额外时延取平均值,获得额外时延。Alternatively, the first additional delay obtained by subtracting the self-loop sending timestamp from the self-loop receiving timestamp of the sending end, and the second additional delay obtained by subtracting the self-loop sending timestamp from the self-loop receiving timestamp of the receiving end are averaged , to obtain an additional delay.

所述时延特性还包括时延抖动,步骤a中发送端在一段时间内生成两个或两个以上测量报文;The delay characteristics also include delay jitter, and in step a, the sending end generates two or more measurement messages within a period of time;

则步骤c还包括计算时延特性中的时延抖动的方法,为:从该段时间内生成的所有测量报文的时延中选出最大时延和最小时延,并将最大时延减去最小时延,获得发送端和接收端的时延抖动。Then step c also includes a method for calculating the delay jitter in the delay characteristic, which is: select the maximum delay and the minimum delay from the delays of all measurement messages generated within this period, and reduce the maximum delay by Remove the minimum delay to obtain the delay jitter of the sending end and the receiving end.

由上述技术方案可见,本发明的这种数据通信网络中时延特性的测量方法通过上层软件仿真出测量报文,并通过网络设备的微码或硬件(微码/硬件)对测量报文进行时间戳标记,获得测量报文在网络传输的时间,最终计算出所测量网络的时延特性。Visible by above-mentioned technical scheme, the measurement method of time delay characteristic in this data communication network of the present invention emulates measurement message by upper layer software, and carries out measurement message by microcode or hardware (microcode/hardware) of network equipment Timestamp marks to obtain the transmission time of the measurement message in the network, and finally calculate the delay characteristics of the measured network.

该方法在真实业务环境下生成测量报文,其测量获得的时延参数能反映实际环境下的业务流延时情况,属于在线测量。另外,该方法利用网络设备的微码/硬件进行时间记录,不需要借助额外的测量仪器和特殊功能的辅助设备,故实现简单且在时间记录的准确性上远高于上层软件。The method generates a measurement message in a real business environment, and the time delay parameter obtained by the measurement can reflect the business flow delay situation in the real environment, which belongs to the online measurement. In addition, this method utilizes the microcode/hardware of the network device to record the time without the need for additional measuring instruments and auxiliary equipment with special functions, so the implementation is simple and the accuracy of time recording is much higher than that of the upper-layer software.

进一步地,该方法可以通过本端自环计算出额外时延,对测量获得的时延特性进行补偿校正,从而获得更高的测量精度,在100M以太网上可以得到10μs量级的报文时延精度。Furthermore, this method can calculate the extra delay through the self-loop at the local end, and compensate and correct the measured delay characteristics, so as to obtain higher measurement accuracy, and a message delay of 10 μs can be obtained on the 100M Ethernet precision.

附图说明 Description of drawings

图1为本发明一个较佳实施例中实现时延特性测量的流程;Fig. 1 is the flow process that realizes delay characteristic measurement in a preferred embodiment of the present invention;

图2为本发明一个较佳实施例中进行误差补偿的流程。FIG. 2 is a flowchart of error compensation in a preferred embodiment of the present invention.

具体实施方式 Detailed ways

为使本发明的目的、技术方案及优点更加清楚明白,以下参照附图并举实施例,对本发明进一步详细说明。In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and examples.

图1所示的是本发明一较佳实施例中,数据包在某段网络中的时延特性的测量流程。假设该段网络的发端设备为A,收端设备为B,所述发端设备A与收端设备B分别是网络两端的任意网络设备,比如路由器等。所述路由器可以采用网络处理器来实现,网络处理器是数据通信设备上可编程的数据帧处理部件,通常有几十个到几百个处理单元并行运作,能完成查表、帧处理、报文转发和丢弃等操作,并具有硬件和微码功能。该方法具体包括以下步骤:FIG. 1 shows a flow of measuring delay characteristics of data packets in a certain segment of network in a preferred embodiment of the present invention. Assume that the originating device of the network is A, and the receiving device is B, and the originating device A and the receiving device B are respectively any network devices at both ends of the network, such as a router. The router can be implemented by using a network processor. The network processor is a programmable data frame processing unit on the data communication device. Usually, dozens to hundreds of processing units operate in parallel, and can complete table lookup, frame processing, and reporting. Operations such as file forwarding and discarding, and has hardware and microcode functions. The method specifically includes the following steps:

步骤101、发端设备A的上层软件仿真实际业务流生成至少一个测量报文,通过微码/硬件在所生成的测量报文上逐个标记第一发送时间戳t1,并将标记了时间戳的测量报文发给收端设备B。Step 101, the upper layer software of the originating device A simulates the actual service flow to generate at least one measurement message, marks the first transmission time stamp t1 one by one on the generated measurement message through the microcode/hardware, and marks the measurement message with the time stamp The packet is sent to receiving device B.

该步骤中,上层软件能够生成具有任意源地址、目的地址、报文长度、优先级、协议号和端口号的测量报文,这种仿真方法在现有技术中普遍使用,此处不赘述。此外,上层软件在生成测量报文时,会给测量报文标上特定的测量报文标识。In this step, the upper-layer software can generate a measurement message with any source address, destination address, message length, priority, protocol number and port number. This simulation method is commonly used in the prior art and will not be described here. In addition, when the upper layer software generates the measurement message, it will mark the measurement message with a specific measurement message identifier.

所述微码(Picocode/Microcode)是网络处理器执行的专有二进制代码。在微码中定义一个标记时间戳动作,使微码能在上层软件送至的测量报文上标记时间戳。在实际系统中,上述功能也可用数字逻辑电路等硬件来完成。The microcode (Picocode/Microcode) is a proprietary binary code executed by the network processor. Define a time stamp action in the microcode, so that the microcode can mark the time stamp on the measurement message sent by the upper layer software. In an actual system, the above functions can also be accomplished by hardware such as digital logic circuits.

步骤102、测量报文经由数据通信网络发送到收端设备B后,收端设备B通过自身的微码/硬件从众多数据包中分离出上述测量报文,并在分离出的测量报文上逐个标记第一接收时间戳t2。所述数据通信网络包括Internet、国家骨干网、省干网、城域网、接入网、企业网以及各种专网。Step 102, after the measurement message is sent to the receiving end device B via the data communication network, the receiving end device B separates the above measurement message from many data packets through its own microcode/hardware, and writes the measurement message on the separated measurement message Mark the first reception timestamp t2 one by one. The data communication network includes Internet, national backbone network, provincial backbone network, metropolitan area network, access network, enterprise network and various private networks.

该步骤中,微码/硬件根据测量报文标识来分离测量报文。上述分离过程采用的是现有的流分类匹配方法,比如可以用三态内容寻址存储器(TCAM)实现等,此处不赘述。In this step, the microcode/hardware separates the measurement message according to the measurement message identifier. The above separation process adopts the existing flow classification matching method, for example, it can be realized by Tri-State Content Addressable Memory (TCAM), etc., which will not be described here.

步骤103、收端设备B通过自身的微码/硬件为接收到的测量报文逐个标记第二发送时间戳t3,再将测量报文通过出端口发给发端设备A。Step 103: The receiving device B marks the received measurement messages with the second transmission time stamp t3 one by one through its own microcode/hardware, and then sends the measurement messages to the sending device A through the egress port.

在收端设备B的出端口,一个测量报文从打上时间戳到最后一个字节的最后一个比特离开出端口,处理时间在20微秒以下,且上述处理时间基本恒定,故该方法的时延测量精度能达到0.1ms,满足承载语音网络的精度要求。At the output port of the receiving device B, the processing time of a measurement message from the timestamp to the last bit of the last byte is less than 20 microseconds, and the above-mentioned processing time is basically constant, so the time of this method is The delay measurement accuracy can reach 0.1ms, which meets the accuracy requirements of the voice network.

步骤104、测量报文经由数据通信网络发送回发端设备A后,发端设备A的微码/硬件通过流分类匹配分离出测量报文,为其逐个打上第二接收时间戳t4,再将测量报文送至发端设备A的上层软件。Step 104: After the measurement message is sent back to the originating device A via the data communication network, the microcode/hardware of the originating device A separates the measurement message through flow classification and matching, stamps the second receiving time stamp t4 on it one by one, and then sends the measurement report The file is sent to the upper layer software of the originating device A.

步骤105、发端设备A的上层软件取出测量报文中记录的所有时间戳,计算出收发端设备之间网络的时延特性。Step 105, the upper layer software of the originating device A extracts all time stamps recorded in the measurement message, and calculates the delay characteristics of the network between the transmitting and receiving end devices.

上述过程中,上层软件可以根据记录的所有时间戳计算出时间差、时延和时延抖动等时延特性。In the above process, the upper-layer software can calculate time delay characteristics such as time difference, time delay and time delay jitter based on all recorded time stamps.

1、通常情况下,网络设备的时间是不一致的。时间差指的是同一时刻,发端设备A和收端设备B标示的时间差值,比如某时刻发端设备A的时间为11:00,收端设备B的时间为9:00,二者的时间差为2小时。1. Usually, the time of network devices is inconsistent. The time difference refers to the time difference marked by the sending device A and the receiving device B at the same time. For example, at a certain moment, the time of the sending device A is 11:00, and the time of the receiving device B is 9:00. The time difference between the two is 2 hours.

计算时间差的方法如下:上层软件逐个判断测量报文中记录的来回路径是否一致,如果来回路径一致,则根据公式(1)计算出每个测量报文记录的时间差z,再将所有测量报文的计算结果取平均值,获得收发设备之间的时间差。The method of calculating the time difference is as follows: the upper layer software judges whether the round-trip paths recorded in the measurement messages are consistent one by one. If the round-trip paths are consistent, calculate the time difference z recorded in each measurement message according to the formula (1), and then compare all the measurement messages to The calculation results are averaged to obtain the time difference between the sending and receiving devices.

z=(t2+t3-t1-t4)/2             (1)z=(t2+t3-t1-t4)/2 (1)

在IP网络中,可以通过ICMP报文路径跟踪,来获得报文来回路径;在MPLS网络中,建立MPLS LSP隧道时,利用MPLS TE的信令路径记录方法获得报文来回路径。On an IP network, the round-trip path of the packet can be obtained through ICMP packet path tracing; on an MPLS network, when an MPLS LSP tunnel is established, the round-trip path of the packet can be obtained by using the signaling path recording method of MPLS TE.

当某些测量报文来回路径不一致时,根据公式(1)计算出所有测量报文的时间差再取平均值,对获取收发设备之间的时延特性也具有一定的参考价值。When the back and forth paths of some measurement messages are inconsistent, the time difference of all measurement messages is calculated according to the formula (1) and then averaged, which also has a certain reference value for obtaining the delay characteristics between sending and receiving devices.

2、根据公式(2)计算每个测量报文的时延x,再将所有测量报文的时延取平均值,获得收发设备的时延。2. Calculate the time delay x of each measurement message according to the formula (2), and then average the time delays of all the measurement messages to obtain the time delay of the sending and receiving device.

x=t2-t1-z=t2-t1-(t2+t3-t1-t4)/2        (2)x=t2-t1-z=t2-t1-(t2+t3-t1-t4)/2 (2)

3、计算时延抖动。时延抖动(jitter)指的是一段时间内,时延最大报文与时延最小报文的时延之差。由于时延抖动不受报文时延的影响,也就是不受两端时间差和报文流分类处理的影响,所以其测量精度比时延的测量精度高1-2个数量级。3. Calculate the delay jitter. Delay jitter (jitter) refers to the delay difference between a packet with the largest delay and a packet with the smallest delay within a period of time. Since the delay jitter is not affected by the delay of the message, that is, it is not affected by the time difference between the two ends and the classification processing of the message flow, so its measurement accuracy is 1-2 orders of magnitude higher than that of the delay.

在图1所示的流程中,微码/硬件在测量报文上标记的时间戳由硬件时钟提供。所述硬件时钟采用本地晶振产生信号源,可以选用64位计数器实现,精度达到10ppm。在时延特性测量过程中,当发端设备A与收端设备B的时钟频率不一致时,可以通过数据通信网络的现有协议在A、B设备之间通告时间调整因子,使二者的时钟频率保持一致。In the process shown in FIG. 1 , the time stamp marked by the microcode/hardware on the measurement message is provided by the hardware clock. The hardware clock uses a local crystal oscillator to generate a signal source, which can be realized by using a 64-bit counter with an accuracy of 10ppm. During the delay characteristic measurement process, when the clock frequency of the source device A and the receiver device B are inconsistent, the time adjustment factor can be notified between A and B devices through the existing protocol of the data communication network, so that the clock frequency of the two devices be consistent.

在高速以太网中,一个报文从第一个字节的第一个比特进入设备入端口,执行流分类匹配,到打上时间戳,整个过程由微码/硬件完成的处理时间在20微秒以下。由于实际的业务报文不打时间戳,所以上述处理时间是额外引入的,会增加测量误差。In high-speed Ethernet, a packet enters the ingress port of the device from the first bit of the first byte, performs flow classification matching, and stamps the time. The entire process is completed by microcode/hardware within 20 microseconds. the following. Since the actual service packets are not time-stamped, the above-mentioned processing time is additionally introduced, which will increase measurement errors.

在对测量精度要求不高的承载语音网络中,上述实施例所述的测量方法已经能够满足其精度要求。进一步地,为了提高时延特性的测量精度,适应其它网络应用的需求,还可以在测量过程中执行本端自环,从而计算出微码/硬件在标记时间戳和流分类匹配过程中引入的额外时延Tz,以便对最终的测量结果进行补偿校正,具体过程如图2所示:In a bearer voice network that does not require high measurement accuracy, the measurement methods described in the above embodiments can already meet the accuracy requirements. Furthermore, in order to improve the measurement accuracy of the delay characteristics and meet the needs of other network applications, the local end self-loop can also be performed during the measurement process, so as to calculate the microcode/hardware introduced in the marking timestamp and flow classification The additional time delay Tz is used to compensate and correct the final measurement results. The specific process is shown in Figure 2:

步骤201、发端设备A的上层软件生成目的地址为自身地址的自环测量报文,并通过微码/硬件在上述自环测量报文上标记自环发送时间戳t5,并发出所述自环测量报文。Step 201, the upper layer software of the originating device A generates a self-loop measurement message whose destination address is its own address, and marks the self-loop transmission time stamp t5 on the above-mentioned self-loop measurement message through microcode/hardware, and sends the self-loop measurement message. Measurement messages.

步骤202、自环测量报文经过数据通信网络返回发端设备A后,发端设备A的微码/硬件通过流分类匹配分离出自环测量报文,为其打上自环接收时间戳t6,再将自环测量报文送至发端设备A的上层软件。Step 202, after the self-loop measurement message returns to the originating device A through the data communication network, the microcode/hardware of the originating device A separates the self-loop measurement message through flow classification matching, stamps the self-loop receiving time stamp t6 on it, and then sends the self-loop The ring measurement message is sent to the upper layer software of the originating device A.

步骤203、上层软件根据自环测量报文中记录的自环发送时间戳t5和自环接收时间戳t6,计算出额外时延Tz。其中,Tz=t6-t5。Step 203 , the upper layer software calculates the extra time delay Tz according to the self-loop sending time stamp t5 and the self-loop receiving time stamp t6 recorded in the self-loop measurement message. Among them, Tz=t6-t5.

步骤204、上层软件根据计算获得的额外时延Tz对时延特性进行补偿校正。Step 204, the upper-layer software compensates and corrects the delay characteristic according to the calculated extra delay Tz.

例如,对于时延x,经过补偿校正后的时延Tx=x-Tz。For example, for the time delay x, the time delay after compensation and correction is Tx=x-Tz.

上述过程中,也可以由收端设备B通过本端自环计算出额外时延Tz;或者,由发端设备A计算出第一额外时延Tz1,收端设备B计算出第二额外时延Tz2,然后取第一额外时延Tz1和第二额外时延Tz2的平均值,获得额外时延Tz。In the above process, the additional delay Tz can also be calculated by the receiving device B through the local self-loop; or, the first additional delay Tz1 can be calculated by the transmitting device A, and the second additional delay Tz2 can be calculated by the receiving device B , and then take the average value of the first extra time delay Tz1 and the second extra time delay Tz2 to obtain the extra time delay Tz.

实际测试表明,经过补偿校正后获得的时延特性达到10μs量级精度。The actual test shows that the time delay characteristic obtained after compensation and correction can reach the precision of 10μs order.

此外,上层软件还可以根据需要多次发送测量报文并记录时间,再用统计方法得到对应网络更为精确的时延特性。In addition, the upper-layer software can also send measurement messages multiple times as needed and record the time, and then use statistical methods to obtain more accurate delay characteristics of the corresponding network.

由上述的实施例可见,本发明的这种数据通信网络中时延特性的测量方法,通过网络设备的微码/硬件对上层软件生成的测量报文进行时间戳标记,从而计算出网络的时延特性。该方法实现简单,不会影响实际运营业务,并能很好地获得网络所需的测量精度。It can be seen from the above-mentioned embodiments that the method for measuring the delay characteristic in the data communication network of the present invention uses the microcode/hardware of the network device to perform timestamp marking on the measurement message generated by the upper layer software, thereby calculating the time delay of the network. extension characteristics. The method is simple to implement, does not affect actual operation services, and can well obtain the measurement accuracy required by the network.

Claims (7)

1, the method for measurement of delay character in a kind of data communication network is characterized in that this method may further comprise the steps:
A, transmitting terminal generate at least one measured message when sending packet to receiving terminal, be the measured message that generated mark first transmitting time stamp one by one by self microcode/hardware, and above-mentioned measured message is sent; Receiving terminal is isolated measured message from the packet that receives, and with self microcode/hardware be isolated measured message one by one mark first time of reception stab;
B, receiving terminal are isolated measured message mark second transmitting time stamp one by one with the microcode/hardware of self, and by data communication network above-mentioned measured message are sent to transmitting terminal; Transmitting terminal is isolated described measured message from the packet that receives, and with self microcode/hardware be isolated measured message one by one mark second time of reception stab;
It is the measured message of ring certainly of self that c1, transmitting terminal and/or receiving terminal generate destination address, by microcode/hardware be described oneself encircle the measured message mark and send timestamp from environment-development, and will encircle measured message certainly and send;
C2, transmitting terminal and/or receiving terminal are isolated described from encircling measured message from the packet that receives, and with microcode/hardware be isolated oneself encircle the measured message mark and receive timestamp from articulating;
C3, receiving timestamp and sending timestamp to calculate extra time delay according to transmitting terminal and/or receiving terminal from environment-development from articulating;
C, first transmitting time stamp according to measured message institute mark, first time of reception stamp, second transmitting time stamp and second time of reception stab, and calculate the time delay in the delay character between transmitting terminal and the receiving terminal; Described time delay is deducted extra time delay, the time delay behind the acquisition compensation correction.
2, method according to claim 1 is characterized in that, the measured message that generates among the step a has the measured message sign;
Then the separating and measuring method of message is: according to the measured message sign, use the traffic classification matching process to isolate measured message.
3, method according to claim 2 is characterized in that, described traffic classification matching process adopts three-state content addressing memory to realize.
4, method according to claim 1, it is characterized in that, described delay character comprises the time difference, then step c also comprises the method for the time difference in the calculation delay characteristic, for: first time of reception stamp of each measured message is added second transmitting time stamp sum, deduct first transmitting time stamp and add second time of reception stamp sum, the difference of acquisition is divided by two; Again the result of calculation of all measured message is averaged, obtain the time difference of transmitting terminal and receiving terminal.
5, method according to claim 1, it is characterized in that, the method of the time delay in the delay character between described calculating transmitting terminal of described step c and the receiving terminal is: first time of reception stamp of each measured message is added second time of reception stamp sum, deduct first transmitting time stamp and add second transmitting time stamp sum, the difference that obtains obtains the time delay of each measured message divided by two; Again the time delay of all measured message is averaged, obtain the time delay of transmitting terminal and receiving terminal.
6, method according to claim 5 is characterized in that, the method for the extra time delay of the described calculating of step c3 is:
Send timestamp with deducting from environment-development of transmitting terminal, obtain extra time delay from articulating receipts timestamp;
Perhaps, send timestamp, obtain extra time delay deducting from environment-development of receiving terminal from articulating receipts timestamp;
Perhaps, send first extra time delay of timestamp acquisition and deducting from environment-development of receiving terminal to send the second extra time delay of timestamp acquisition to average deducting from environment-development of transmitting terminal, obtain extra time delay from articulating receipts timestamp from articulating receipts timestamp.
7, method according to claim 5 is characterized in that, described delay character also comprises delay variation, and transmitting terminal generates two or more measured message among the step a in a period of time;
Then step c also comprises the method for the delay variation in the calculation delay characteristic, for: maximum delay and minimal time delay are selected in the time Yanzhong of all measured message that generate in the period from this section, and maximum delay deducted minimal time delay, obtain the delay variation of transmitting terminal and receiving terminal.
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