CN109286814B

CN109286814B - Method and equipment for detecting IPTV service in passive optical network

Info

Publication number: CN109286814B
Application number: CN201710589285.0A
Authority: CN
Inventors: 董志华
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2017-07-19
Filing date: 2017-07-19
Publication date: 2022-07-12
Anticipated expiration: 2037-07-19
Also published as: CN109286814A

Abstract

The invention discloses a method and equipment for detecting IPTV service in a passive optical network, relating to the technology of the passive optical network. The method disclosed herein comprises: each node in the access network respectively calculates the media transmission quality index MDI of the node; inserting the calculated MDI value into a predefined real-time transmission control protocol (RTCP) message, and transmitting MDI information layer by layer; wherein, the MDI comprises one or more of the following components: a time delay factor DF, an average media packet loss rate MLR, a time delay of MDI and an MDI packet loss rate.

Description

Method and equipment for detecting IPTV service in passive optical network

Technical Field

The invention relates to a Passive Optical Network (Passive Optical Network) technology, in particular to an end-to-end measurement scheme for IPTV video stream transmission quality in the Passive Optical Network.

Background

With the development of the optical fiber network, the network access rate of users is gradually increased, and IPTV (interactive network television) becomes a killer-level service pursued by many operators. The IPTV service is a service with high real-time performance and large data volume, the user experience is very important, the requirement on the quality of a bearing network is very strict, and phenomena such as mosaic and black screen can occur when the network shakes for 5 ms. For conventional users, it is of course desirable to watch television via IPTV, and to have video quality as good as or even better than that of digital television. Therefore, whether IPTV can provide better user experience (QoE) is a key to success. Compared with the prior art, the optical network terminal only pays attention to the network service quality (QoS) of a transmission layer, pays attention to the network transmission quality, measures the network performance by measuring indexes such as time delay, jitter and packet loss, does not consider the particularity of the IPTV network, and cannot well detect the performance of the IPTV network, so that it is obviously not suitable to evaluate the video quality of the IPTV by using the QoS.

Disclosure of Invention

The present disclosure provides a method and an apparatus for detecting an IPTV service in a passive optical network, which can solve the problem in the related art that the performance of the IPTV network cannot be detected.

The text discloses a method for detecting an interactive network television IPTV service in a passive optical network, which comprises the following steps:

each node in the access network respectively calculates the media transmission quality index MDI of the node;

inserting the calculated MDI value into a predefined real-time transport control protocol (RTCP) message, and transmitting MDI information layer by layer;

wherein, the MDI comprises one or more of the following components:

a time delay factor DF, an average media packet loss rate MLR, a time delay of MDI and an MDI packet loss rate.

Optionally, in the foregoing method, the separately calculating, by each node in the access network, a media transmission quality indicator MDI of the node includes:

when the ith multimedia video packet p (i) arrives, the virtual buffer VB before and after arrival of p (i) is calculated according to the following formula:

VB＝VB(i,pre)+VB(i,post)；

VB(i,pre)＝sum(Sj)–MR*Ti(j＝1…i-1)；

VB(i,post)＝VB(i,pre)+Si；

in the formula, VB (i, pre) is a virtual buffer before the ith multimedia video packet arrives;

sum (sj) is the sum of the PAYLOAD of all the arrived packets in the sampling period before the ith multimedia video packet p (i) arrives;

MR is the media flow rate, Ti is the time difference between the arrival of P (i) and the beginning of the period;

VB (i, post) is the virtual cache after the ith multimedia video packet arrives;

si is the video content size of the ith multimedia video packet P (i);

then calculate DF from the calculated VB:

DF＝(max(VB)-min(VB))/MR；

wherein max (VB) and min (VB) are the VB maximum value and the VB minimum value of all the multimedia video packets calculated in each statistical period.

Optionally, in the foregoing method, the node in the access network includes one or more of the following devices:

an optical line terminal OLT, an optical network unit ONU and a set-top box.

Optionally, the method further includes:

and when information query and fault location are carried out, the predefined RTCP message is captured to obtain MDI information, and the fault node is quickly located.

Optionally, in the foregoing method, the inserting the calculated value of MDI into the predefined RTCP packet includes:

and calculating the MDI value of the node, including DF, average MLR, 15-minute delay factor DF15, MLR15, 24-hour delay factor DF24 and MLR24, and encapsulating DF, average MLR, DF15, MLR15, DF24 and MLR24 into a predefined RTCP message layer by layer.

The present document also discloses an apparatus for detecting an IPTV service of an interactive network television in a passive optical network, which includes:

the computing module is used for computing the media transmission quality index MDI of the node;

The message generation module is used for inserting the calculated MDI value into a predefined real-time transport control protocol (RTCP) message and transmitting the MDI information layer by layer;

wherein, the MDI comprises one or more of the following components:

Optionally, in the foregoing device, the calculating module, calculating a media transmission quality indicator MDI of the node, includes:

VB＝VB(i,pre)+VB(i,post)；

VB(i,pre)＝sum(Sj)–MR*Ti(j＝1…i-1)；

VB(i,post)＝VB(i,pre)+Si；

si is the video content size of the ith multimedia video packet P (i);

then calculate DF from the calculated VB:

DF＝(max(VB)-min(VB))/MR；

Optionally, in the above device, the device is an optical line terminal OLT, an optical network unit ONU, or a set-top box.

Optionally, in the above apparatus, the inserting, by the message generation module, the calculated MDI value into the predefined RTCP message includes:

and when calculating the MDI value of the node comprises DF, average MLR, 15-minute delay factor DF15, MLR15, 24-hour delay factor DF24 and MLR24, packaging the DF, the average MLR, DF15, MLR15, DF24 and MLR24 into a predefined RTCP message layer by layer.

According to the technical scheme, the node position causing the IPTV service flow congestion can be quickly positioned by deploying the MDI monitoring module at each node in the optical network and actively inserting the RTCP message carrying the MDI information, and the operation and maintenance working efficiency is improved.

Drawings

Fig. 1 is a topology diagram of an IPTV access network system according to an embodiment of the present invention;

FIG. 2 is an example of a media packet format of an embodiment of the present invention;

FIG. 3 is a general flow diagram in an embodiment of the invention;

fig. 4 shows a format of a predefined SCTP application packet MDI in the embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in further detail with reference to specific embodiments. It should be noted that the embodiments and features of the embodiments of the present application may be arbitrarily combined with each other without conflict.

In view of the problem that the performance of the IPTV network cannot be detected in the related art, the inventor of the present application proposes that the capability of each node in the network for processing the IPTV packet can be detected in real time, which is different from the conventional idea of collecting information of the drop-off device through a central server, that is, the inventor of the present application uses a mode of inserting a predefined RTCP packet (i.e., an SCTP-specific APP packet) to carry MDI information of each node in the packet, thereby implementing decentralized management, improving efficiency, and quickly finding and locating the problem.

Based on the above idea, this embodiment provides a method for detecting an IPTV service in a passive optical network, which mainly includes the following operations:

each node in the access network respectively calculates the parameter of media transmission quality index MDI;

inserting the calculated value of the MDI parameter into a predefined RTCP message, and transmitting MDI information layer by layer;

wherein, the MDI parameters comprise one or more of the following:

In the method, the calculation of the media transmission quality index MDI parameter is carried out on each node, and the value of the calculated MDI parameter is inserted into the predefined RTCP message, so that the capability of each node for processing the IPTV message can be reflected, the network caching capability of each node is reflected through the MDI parameter of each node, and the problem that the watching perception of a user on the IPTV cannot be effectively expressed by the traditional network measuring method is solved.

Specifically, the implementation of the above scheme may include the following operations:

step A, defining the calculation of a Delay Factor (DF) and an average media packet loss ratio (MLR) realized on an Optical Network Unit (ONU), so as to convert the change of the video stream jitter into the requirement on the video transmission cache.

In this step, assuming that the virtual buffer at the measurement point (i.e. node) is VB, when the ith multimedia video packet p (i) arrives, VB before arrival and VB after arrival of p (i) can be calculated, which are collectively referred to as VB, and the formula is as follows:

VB＝VB(i,pre)+VB(i,post)；VB(i,pre)＝sum(Sj)–MR*Ti(j＝1…i-1)

VB(i,post)＝VB(i,pre)+Si

where VB (i, pre) is P (i) before arrival VB, sum (Sj) is P (i) before arrival, P (i) is the sum of the PAYLOADs of all the packets that have arrived within the sampling period, MR is the media coderate, and Ti is the time difference between the arrival of P (i) and the beginning of the period;

VB (i, post) is VB after p (i) arrives, Si is p (i) video content size, and VB (i, pre) and VB (i, post) of all packets in one sampling period are collectively referred to as VB.

DF＝(max(VB)-min(VB))/MR

The unit of MR is: bytes/sec. max (VB) and min (VB) are the VB maximum value and the VB minimum value of all the multimedia video packets calculated in each statistical period.

MLR is the total number of lost media packet/sampling period

Alternatively, the sampling period is typically one second.

And B, collecting the video message. In the step, all media messages are intercepted at corresponding ports of the ONU, so that the acquisition of the data to be analyzed is completed.

In the step B, the video acquisition module may further add a hook callback function to the node where the ONU drives and forwards the data packet, so as to implement an action of intercepting the packet.

In addition, the video acquisition module intercepts all video media packets when the slave driver forwards the video message, and stamps a timestamp for each packet according to the arrival time of each data packet, so that a basis is provided for the calculation of the following indexes.

And C, decoding and analyzing the video packet. Video transmission is carried out on IPTV video according to the protocol stack mode of IP/UDP/RTP/TS.

Rtp (real time protocol) in video packets is a stateless media streaming protocol for transmitting multimedia content, which is based on UPD or TCP.

The ts (transport stream) in the video packet includes multiple voice and video streams encapsulated and carried on RTP, and as shown in fig. 2, the voice and video can be distinguished by PID.

And decoding the video packets in sequence according to the IP/UDP/RTP/TS, and storing the video packets in a corresponding structure for later index calculation.

And D, index calculation, namely performing index calculation according to the decoding result in the step C. In the step, header information is taken out from the data header queue, and the average EF and the MLR are calculated by adopting the algorithm of the step A according to the data adopted per second in the statistical period. The statistical reporting period is typically five minutes.

The sample period for calculating EF is usually 1 second, but in practice, a period may not be a complete second, so a sample period starts from the arrival time of the last packet of the previous period to the arrival of the last packet of the present period. The arrival time of the packets is time stamped in turn at the data acquisition.

And E, respectively executing the step A, B, C, D on the uplink port of the OLT and the network port of the IPTV set-top box, namely realizing the calculation of the MDI user perception parameters at each node in the access network.

Step F, predefining RTCP messages, i.e. application specific messages mi (mdi info), as shown in fig. 4. Respectively writing MDI values of the OLT, the ONU and the set-top box into the specific application message, specifically, firstly generating a predefined RTCP message at the OLT side, and writing the MDI value of the OLT into the corresponding position of the message; after the ONU receives the message, the MDI value which is counted for the last time is written into the corresponding position of the ONU in the message; and in the same way, writing the MDI counted for the last time into the position corresponding to the message on the set-top box. Therefore, an end-to-end closed loop for monitoring the video quality is realized, and each node in the loop and a network administrator can judge the video quality and the position where a fault possibly occurs according to the feedback information.

The utility model also provides a device for detecting IPTV service of interactive network television in passive optical network, for example, OLT, ONU or set-top box, which mainly comprises a fraud module and a message generation module.

The computing module is used for computing a media transmission quality index MDI of the node;

specifically, when the computing module computes the media transmission quality indicator MDI of the node, the following method may be adopted:

when the ith multimedia video packet p (i) arrives, calculating p (i) a virtual buffer VB before and after arrival according to the following formula:

VB＝VB(i,pre)+VB(i,post)；

VB(i,pre)＝sum(Sj)–MR*Ti(j＝1…i-1)；

VB(i,post)＝VB(i,pre)+Si；

si is the video content size of the ith multimedia video packet P (i);

then calculate DF from the calculated VB:

DF＝(max(VB)-min(VB))/MR；

Wherein, the MDI comprises one or more of the following components:

In this embodiment, the message generation module inserts the calculated MDI value into the predefined RTCP message: and when calculating the MDI value of the node, including DF, average MLR, 15-minute delay factor DF15, MLR15, 24-hour delay factor DF24 and MLR24, encapsulating DF, average MLR, DF15, MLR15, DF24 and MLR24 layer by layer into a predefined RTCP message, wherein the message format is shown in FIG. 4.

The invention is further illustrated by the following figures and examples:

fig. 1 shows a basic PON network topology diagram for implementing the technical solution of the present application. As can be seen from the topology diagram, one OLT may be connected to multiple ONUs through an optical splitter, and the downlink data transmission from the OLT to the ONUs is time division multiplexing and physical layer broadcasting, that is, each downlink frame is sent to all the PON ports of the ONUs. The upstream data transmission method from the ONU to the OLT is a TDMA method. The ONU is connected with the IPTV set-top box through the network port, and the service is carried through the IP packet.

Fig. 3 is a flowchart illustrating a specific implementation of the technical solution of the present application, which includes the following steps 301 to 305:

301, adding a data acquisition module on an OLT (optical line terminal), an ONU (optical network unit) network card and a set top box network port;

step 302: collecting and analyzing RTP/TS packets;

the above steps can be divided into the following steps:

in step 302a, the data collection module may be implemented by a video collection module, which intercepts all video media packets when the slave driver forwards the video packet, and stamps a timestamp on each data packet (i.e., video media packet) according to the arrival time of each data packet. The media packets are carried in UDP packets at the IP layer.

Step 302b, parsing rtp (real time protocol) media stream transmission protocol for transmitting multimedia content, the protocol being based on UPD or TCP. And storing the index in a corresponding structure for later index calculation.

In step 302c, a TS (transport stream) packet is parsed, and the TS packet is carried on RTP and can be distinguished between voice and video by PID. Also stored in the corresponding structure for later index calculation.

Step 303: and c, calculating MDI parameter indexes at least comprising the time delay and the packet loss rate of the MDI according to the analysis results in the steps 302b and c.

In the step, header information is taken out from the data header queue, and average EF and MLR are calculated according to sampling data per second in a statistical period. Alternatively, the statistical period is typically five minutes. The specific operation is as follows:

And step 303a, calculating the time delay and the packet loss rate of the MDI. Assuming that the virtual buffer at the measurement point is VB, when the ith packet p (i) arrives, VB before and after p (i) arrives can be calculated, as follows:

VB(i,pre)＝sum(Sj)–MR*Ti(j＝1…i-1)

VB(i,post)＝VB(i,pre)+Si

sum (sj) is p (i) the sum of PAYLOAD of all packets that have arrived in the sampling period before arrival, MR is the media coderate, Ti is the time difference between the arrival of p (i) and the start of the period, Si is p (i) the video content size, and VB (i, pre) and VB (i, post) of all packets in a sampling period are collectively referred to as VB.

EF＝(max(VB)-min(VB))/MR

MLR is the total number of lost media packets/sampling period.

Step 303b, calculating average MDI delay and packet loss rate in the period, and generally setting the period to default to five minutes, that is, the period for generating the MI message. In order to prevent errors and under-fitting or over-fitting states, the average delay and the packet loss rate of 15 minutes or 24 hours can be counted and written into the MI message.

Step 304: inserting a predefined RTCP message into a network, and transmitting MDI information layer by layer;

this step can be divided into the following operations:

Step 304 a: the OLT generates a predefined RTCP packet, that is, an SCTP specific application packet MI, and writes MDI information in a statistical period into a corresponding location as shown in fig. 4, where the specific information may be: delay factor DF, MLR, 15 minute delay factor (DF15), MLR15, 24 hour delay factor (DF24), MLR 24;

step 304 b: the OLT inserts an STCP-specific application Message (MI) into the network.

Step 304 c: and after receiving the STCP specific application Message (MI), the ONU and the STB respectively write the MDI information in the latest statistical period into the message.

Step 305: when information inquiry and fault location are carried out, a network message is captured, an RTCP special application message is analyzed, or an MDI display page is added to a web page of the ONU and the STB for inquiry, and a fault node is located quickly.

It can be seen from the foregoing embodiments that, in the present application, video packets are sampled at regular time, and the caching capability of the network is calculated according to the samples, so that the measurement of packet loss and jitter of the conventional network is converted into the measurement of the caching capability of the network, thereby solving the problem that the viewing perception of the IPTV by the user cannot be effectively expressed by the conventional network measurement method. And moreover, the mode of inserting the RTCP control message into the RTP message is used for controlling the user perception information (MDI value) of each node (OLT, ONU, STB) to be carried in the message, so that the end-to-end information transmission of the quality of the video message is realized, and operation and maintenance personnel can quickly judge which node needs to be checked for faults, thereby improving the processing efficiency, reducing the influence on the perception of the user to the maximum extent, and providing a good analysis means for operators to know the IPTV service quality and the delimitation and positioning of the faults.

It will be understood by those skilled in the art that all or part of the steps of the above methods may be implemented by instructing the relevant hardware through a program, and the program may be stored in a computer readable storage medium, such as a read-only memory, a magnetic or optical disk, and the like. Alternatively, all or part of the steps of the above embodiments may be implemented using one or more integrated circuits. Accordingly, each module/unit in the above embodiments may be implemented in the form of hardware, and may also be implemented in the form of a software functional module. The present application is not limited to any specific form of hardware or software combination.

The above description is only a preferred example of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting IPTV service of an interactive network television in a passive optical network comprises the following steps:

the calculated MDI value is sequentially inserted into a predefined real-time transmission control protocol (RTCP) message transmitted among all nodes, so as to detect the capability of each node in the network for processing the IPTV message according to the MDI information of each node carried in the predefined RTCP message;

Wherein, the MDI comprises one or more of the following components: the delay factor DF, the average media packet loss rate MLR, the delay of MDI and the packet loss rate of MDI.

2. The method of claim 1, wherein the step of calculating the media transmission quality indicator MDI of the node by each node in the access network respectively comprises:

VB＝VB(i,pre)+VB(i,post)；

VB(i,pre)＝sum(Sj)–MR*Ti(j＝1…i-1)；

VB(i,post)＝VB(i,pre)+Si；

sum (sj) is the sum of PAYLOAD of all the arrived packets in the sampling period before the ith multimedia video packet p (i) arrives;

si is the video content size of the ith multimedia video packet P (i);

then calculate DF from the calculated VB:

DF＝(max(VB)-min(VB))/MR；

3. The method according to claim 1 or 2, wherein the nodes in the access network comprise one or several of the following devices:

An optical line terminal OLT, an optical network unit ONU and a set-top box.

4. The method of claim 3, further comprising:

and when information inquiry and fault location are carried out, capturing the predefined RTCP message to obtain MDI information, and quickly locating the fault node.

5. The method of claim 3, wherein sequentially inserting the calculated value of MDI into predefined real time transport control protocol (RTCP) packets communicated between the nodes comprises:

6. An apparatus for detecting an IPTV service in a passive optical network, comprising:

the message generation module is used for sequentially inserting the calculated MDI value into a predefined real-time transport control protocol (RTCP) message transmitted among all nodes so as to detect the capability of each node in the network for processing the IPTV message according to the MDI information of each node carried in the predefined RTCP message;

Wherein, the MDI comprises one or more of the following components: a time delay factor DF, an average media packet loss rate MLR, a time delay of MDI and an MDI packet loss rate.

7. The apparatus of claim 6, wherein the calculating module calculates a media transmission quality indicator (MDI) of the node, and comprises:

VB＝VB(i,pre)+VB(i,post)；

VB(i,pre)＝sum(Sj)–MR*Ti (j＝1…i-1)；

VB(i,post)＝VB(i,pre)+Si；

si is the video content size of the ith multimedia video packet P (i);

then calculate DF from the calculated VB:

DF＝(max(VB)-min(VB))/MR；

8. The device according to claim 6 or 7, wherein the device is an optical line termination, OLT, an optical network unit, ONU or a set-top box.

9. The apparatus of claim 8, wherein the message generation module to sequentially insert the calculated value of the MDI in a predefined real-time transport control protocol RTCP message communicated between the nodes comprises: