CN101217451B - A method and system to reduce time delay influence - Google Patents
A method and system to reduce time delay influence Download PDFInfo
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Abstract
The invention discloses a method for controlling delay in TDM over IP, which is used for stripping out the payload in the packet switching data packet and sealing the payload as TDM data-frame, comprising the following procedures: A. arranging downlink caching water line value which is used for storing the payload according to the correctness of the TDM data-frame; B. storing the payload strippedout of the packet switching data packet into the downlink cache; C. judging if the payload capacity stored in the downlink cache is more than the water line value, if yes, extracting the payload fromthe downlink cache and assembling the payload into TDM data frame and sending the data frame to the TDM processing module and then turning to step B; if not, turning to step B directly. The inventionalso discloses a system which is used for realizing the method. The invention can effectively reduce the effect of time delay on the TDM over IP business.
Description
Technical Field
The present invention relates to the field of network switching technologies, and in particular, to a method and a system for reducing the effect of Time delay in Time Division Multiplexing over Internet Protocol (TDM over IP) transmission in a packet-switched network.
Background
At present, in order to meet the requirement of the evolution of the communication network architecture, various telecommunication operators urgently want to integrate various communication services into one network for transmission in a lower-cost transmission mode. Due to the characteristics of low cost, wide application range and the like of packet switching networks represented by Internet Protocol (IP) networks, the integration of various services in a unified packet switching network becomes a development trend of the communication industry. In the existing communication network, TDM is a widely adopted network switching technology. Therefore, to integrate services into a network, a method is necessary to transmit TDM services through a packet-switched network.
In the existing switching technology, TDM traffic and packet traffic are transmitted through a TDM network and a packet switching network, respectively, and both the traffic cannot be transmitted in one switching network at the same time. In the last few years, Ethernet Over SONET (EOS) Over Synchronous Optical Networks (SONET) was developed as a technology for switching packet traffic Over TDM networks; however, the TDM service is affected seriously by the problems of time delay, disorder, jitter, etc. in the packet switching network, so that the TDM service transmission through the packet switching network cannot be realized all the time.
The applicant discloses in another application a scheme for transmitting TDM traffic in a packet-switched network, and fig. 1 is a schematic system structure diagram of the scheme.
In the uplink direction, the TDM service from the TDM network 120 is processed by the TDM processing module 111 to generate a TDM specific timeslot signal, which is sent to the format conversion module 112. In the format conversion module 112, the timeslot signal header and the useless overhead signal of the TDM service are stripped off, the data packet header specific to the packet switching is re-encapsulated, and meanwhile, auxiliary information such as timeslot indication is added to the data packet header; the data packet from the format conversion module 112 is the packet service that can be identified by the packet switch, and then the data packet is sent to the packet switch network 130 through the packet switch data processing module 113 for transmission.
In the downlink direction, the format conversion module 112 receives the data packet from the packet switching data processing module 113, parses the data packet header, strips the payload, regenerates the TDM data frame header according to the indication in the data packet header, and assembles the TDM data frame with the payload; finally, the generated TDM data frame is sent to the TDM network 120 through the TDM processing module 111.
Although the above-mentioned flow can realize the TDM service transmission in the IP network, various measures need to be further taken in the flow to ensure that various indexes of the TDM service can be satisfied. Particularly, packet transmission delay inevitably occurs in a packet-switched network, and the TDM network has strict requirements on time slots, so that TDM over IP traffic may be affected by the transmission delay of packets.
Disclosure of Invention
The embodiment of the invention aims to provide a method for reducing the time delay influence, which can effectively reduce the influence of time delay on a TDM over IP service. The method is used for stripping the payload from the packet switching data packet and encapsulating the payload into a TDM data frame, and comprises the following steps:
a1, TDM processing module receives the TDM data frame, judges whether the received TDM data frame is correct, if yes, reports the received TDM data frame as correct, otherwise reports the received TDM data frame as wrong;
a2, judging the reported contents of the current time and the last time, if the reported contents are both correctly received, subtracting 1 from the current waterline value, and executing the step A3;
if the receiving errors are all received, adding 1 to the current water line value, and executing the step A3;
if the current receiving is correct and the last receiving is wrong, turning to the step B;
if the current receiving is wrong and the last receiving is correct, adding 1 to the current water line value and transferring to the step B;
a3, when the payload capacity stored in the downlink buffer is larger than the current waterline value, extracting the payload from the downlink buffer and assembling the payload into a TDM data frame, and sending the TDM data frame to the TDM processing module and turning to the step A1; B. the payload stripped from the packet switching data packet is stored in the downlink cache;
C. judging whether the payload capacity stored in the downlink cache is larger than the set water line value, if so, extracting the payload from the downlink cache, assembling the payload into a TDM data frame, sending the TDM data frame to a TDM processing module, and turning to the step B; otherwise, directly turning to the step B.
The embodiment of the invention also discloses a second method for reducing the time delay influence, which is also applied to the process of stripping the payload from the packet switching data packet and packaging the payload into the TDM data frame, and comprises the following steps:
a1, the TDM processing module receives the TDM data frame, judges whether the received TDM data frame is correct, if yes, reports that the receiving is correct, otherwise reports that the receiving is wrong;
a2, judging the current and last reported contents, if both are received correctly, subtracting 1 from the current waterline value, and executing a step a 3;
if the receiving errors are all received, adding 1 to the current water line value, and executing the step a 3;
if the current receiving is correct and the last receiving is wrong, turning to the step b;
if the current receiving is wrong and the last receiving is correct, adding 1 to the current water line value and transferring to the step b;
a3, when the payload capacity stored in the downlink buffer is larger than the current waterline value, extracting the payload from the downlink buffer and assembling the payload into a TDM data frame, and sending the TDM data frame to the TDM processing module and turning to the step a 1;
b. determining a second water line value according to the determined current water line value, namely a first water line value, and a preset corresponding relation between the first water line value and the second water line value, wherein the first water line value is larger than the second water line value;
c. the payload stripped from the packet switching data packet is stored in the downlink cache;
d. judging whether the payload capacity stored in the downlink cache is larger than the second waterline value, if so, extracting the payload from the downlink cache, assembling the payload into a TDM data frame, sending the TDM data frame to a TDM processing module, and turning to the step c; otherwise, go to step c directly.
The embodiment of the invention also provides a system for reducing the time delay influence, which can effectively reduce the influence of the time delay on the TDM over IP service. The system comprises a TDM processing module and a format conversion module, wherein the format conversion module is used for stripping payloads from a packet switching data packet, assembling the payloads into a TDM data frame and sending the TDM data frame to the TDM processing module. The system also comprises a downlink cache with a waterline, a waterline setting unit and a judging unit;
the downstream cache with the set waterline is used for storing the payload stripped from the packet switching data packet;
the waterline setting unit is used for receiving the condition information of receiving the TDM data frames from the TDM processing module, judging the current and last reported contents, and subtracting 1 from the current waterline value if the receiving is correct; if the data are all reception errors, adding 1 to the current water line value; if the current receiving is wrong and the last receiving is correct, adding 1 to the current water line value; sending the set waterline of the downlink cache to the judging unit; if the current receiving is correct and the last receiving is wrong, keeping the current water line value unchanged;
the judging unit is used for judging whether the storage capacity of the payload reaches a waterline of the received downlink cache, if so, the format conversion module extracts the payload from the downlink cache and assembles the payload into a TDM data frame to be sent to the TDM processing module; otherwise, the format conversion module stores the payload stripped from the packet switching data packet in the downlink cache;
the TDM processing module comprises a reporting unit which is used for generating the condition information of the received TDM data frame and reporting the condition information of the received TDM data frame to the water line setting unit.
According to the technical scheme, the time delay in the packet switching network can be absorbed by setting the downlink cache for storing the payload; and the waterline of the downlink buffer is adjusted according to the TDM data frame receiving condition fed back by the TDM processing module, so that the time delay absorbed by the downlink buffer is consistent with the time delay actually existing in the packet switching network. Therefore, the embodiment of the invention can effectively control the time delay existing in the process that the payloads from the packet switching network are reassembled into the correct TDM data frame and are sent to the TDM network under the condition that the packet switching network has certain transmission time delay, and reduces the influence of the time delay on the TDM over IP service.
Drawings
FIG. 1 is a schematic diagram of a TDM over IP system;
fig. 2 is a basic flowchart of a first embodiment of the present invention.
Fig. 3 is a flowchart of a process triggered when the latency of the packet-switched network is increased according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings.
As can be seen from the description of the background art, the TDM over IP service mainly includes processing in the uplink direction and processing in the downlink direction. Because the TDM network has strict time delay control, the time delay influence basically does not exist in the uplink direction; the processing in the downstream direction is affected by the delay, which inevitably occurs when packets are transmitted in a packet-switched network.
Referring to fig. 1, the embodiment of the present invention mainly includes that a downlink buffer is added in the format conversion module 112 for accommodating the time delay and buffering the payload; and sets an allocable critical threshold, called waterline (watermark). When the payload capacity in the cache is below the waterline, the TDM service is stopped from being sent to the TDM processing module 111, and the payload is stored in the downlink cache; once the payload capacity is larger than the waterline, the payload is extracted from the downstream buffer and encapsulated into TDM traffic, and the encapsulated TDM traffic is sent to the TDM processing module 111. It is obvious that the case where the payload size is equal to the pipeline can be handled as either of the above cases.
Examples of the process of the present invention are described in further detail below.
The first embodiment is as follows: a waterline is set for a downstream cache.
The processing flow of the first embodiment of the present invention is shown in fig. 2, and includes the following steps:
step 201: an initial water line value is set in the format conversion module. The initial water line value can be set by the format conversion module, or can be set by other external modules such as a control module of the system. The initial water line value may be set arbitrarily, but may be an optimum water line value calculated theoretically or an optimum water line value set empirically in order to shorten the processing time of the entire process as much as possible.
Step 202: the format conversion module judges whether the payload capacity in the downlink cache reaches a water line value, if so, the payload in the downlink cache is extracted and encapsulated into TDM service, the TDM service is sent to the TDM processing module, and the step 203 is continuously executed; otherwise, the net load separated from the data packet from the packet switching data processing module is stored in the down buffer and the step is continuously executed.
Step 203: the TDM processing module judges whether the received TDM service is correct, if so, reports that the receiving is correct, and otherwise, reports that the receiving is wrong; the reported object can be a control module of the system or a format conversion module;
step 204: the control module or format conversion module of the system judges the content of the reported information received this time and last time, and executes corresponding operation according to the judged result, specifically:
if all the signals are received correctly or all the signals are received incorrectly, go to step 205; if the current time is correct and the last time is wrong, the process is ended; if the current time is reception error and the last time is reception correct, go to step 206;
if the step is executed for the first time, the control module or the format conversion module of the system directly goes to step 205 after determining the content of the received report message.
Step 205: if the judgment result in the step 204 is that the receiving is correct at the current time and the last time, subtracting 1 from the waterline value on the basis of the original waterline; if the judgment shows that the current time and the last time are both receiving errors, adding 1 to the waterline value on the basis of the original waterline; after the operation of adding 1 or subtracting 1 is performed, the process goes to step 202.
If the step is executed for the first time, the following operations are executed: if the result of the determination in step 204 is correct, the water line value is increased by 1, if the result of the determination in step 204 is incorrect, the water line value is decreased by 1, and if the operation of increasing or decreasing 1 is completed, the procedure goes to step 202.
The format conversion module may need to be restarted to enable it to operate again at the new water line value.
Step 206: and adding 1 to the water line value and ending the flow.
The above-mentioned metering units of adding 1 or subtracting 1 are the number of payload.
Through the above process, the optimal water line value can be determined for the downlink cache. Then, the format conversion module may perform downlink processing according to the determined optimal water line value, specifically: the format conversion module judges whether the payload in the downlink cache reaches the set water line value, if so, the payload in the downlink cache is extracted and encapsulated into TDM service, and the TDM service is sent to the TDM processing module; otherwise, the net load stripped from the data packet from the packet switching data processing module is stored in the downlink buffer and the judgment is continued.
Therefore, under the condition that a certain transmission delay exists in the packet switching network, the payload coming out of the packet switching network is reassembled into a correct TDM data frame and is sent to the TDM network, the influence of the delay is effectively controlled, and the delay is reduced as much as possible.
If the transmission delay of the packet switching network changes in the subsequent service process, the determined waterplane value needs to be adjusted correspondingly to adapt to the delay change situation. When the time delay becomes large, the TDM service received by the TDM processing module may generate an error, and trigger the flow shown in fig. 3:
step 301: in the downlink processing process of the TDM over IP service, the TDM processing module reports a receiving error, and the format conversion module adds 1 to a water line value;
step 302: the format conversion module judges whether the payload capacity in the downlink cache reaches a water line value, if so, the payload in the downlink cache is extracted and encapsulated into TDM service, the TDM service is sent to the TDM processing module, and the step 303 is continuously executed; otherwise, the net load separated from the data packet from the packet switching data processing module is stored in the down buffer and the step is continuously executed.
Step 303: the TDM processing module judges whether the received TDM data frame is correct, if so, reports that the receiving is correct, and otherwise, reports that the receiving is wrong;
step 304: a control module or a format conversion module of the system judges whether the reported content is correctly received, if so, the process is ended, otherwise, the process goes to step 305;
example two: two waterlines are set for one downlink buffer.
This embodiment sets two waterlines for the downstream cache: the values of the waterline a and the waterline b meet a certain functional relationship, and one of the values is set, and the other value is also determined. The format conversion module is correspondingly added with a waterline conversion unit used for obtaining another waterline value according to a set waterline (such as a waterline b) and a functional relationship between the waterline a and the waterline b which is preset.
Step 305: add 1 to the water line and go to step 302.
The flow shown in fig. 3 is a simplified flow of the flow shown in fig. 2. Through the flow, the corresponding adjustment of the water line value can be automatically realized when the transmission delay of the packet switching network becomes longer.
If the transmission delay of the packet switching network becomes smaller, the TDM service received by the TDM processing module does not have errors, and at this time, the waterline value of the downlink cache is not automatically adjusted, so that the time delay absorbed by the downlink cache is still the original time delay. To solve this problem, the process shown in fig. 2 may be triggered again at a specific time interval, and when the process shown in fig. 2 is triggered again, step 201 does not need to be executed, and the process starts directly from step 202. Therefore, when the transmission delay of the packet switching network becomes smaller, the adjustment of the water line value of the downlink buffer can be realized in time. The specific time can be preset by the system, and can also be set according to the actual situation in the service process.
On the basis of the first embodiment of the present invention, the number of the pipelines may be modified, or the size of the cache may be modified to achieve the object of the present invention, which is the content of the second embodiment and the third embodiment.
Example two: two waterlines are set for one downlink buffer.
This embodiment sets two waterlines for the downstream cache: the values of the waterline a and the waterline b meet a certain functional relationship, and one of the values is set, and the other value is also determined. The format conversion module is correspondingly added with a waterline conversion unit used for obtaining another waterline value according to a set waterline (such as a waterline b) and a functional relationship between the waterline a and the waterline b which is preset.
The flow of the embodiment of the present invention is substantially the same as the flow of the first embodiment, except that the setting process of the waterline value is performed for one of the waterlines (for example, the waterline b). When the TDM service is actually sent after the setting is finished, the sending of the TDM service is controlled according to another waterline (such as a waterline a), namely, the format conversion module judges whether the payload in the downlink cache reaches the set waterline value a, if so, the payload in the downlink cache is extracted and encapsulated into the TDM service to be sent to the TDM processing module; otherwise, storing the received payload from the packet switching data processing module into the downlink buffer and continuing to perform the judgment.
Although the payload packets coming out of the packet-switched network can be reassembled into the correct TDM data frame and sent to the TDM network, and the delay in the process is minimal, the state is very unstable: if the delay of the packet-switched network is slightly increased, the delay that can be absorbed by the downlink buffer cannot meet the requirement, and the TDM data frame may be in error, especially under the condition of small-range oscillation of the delay of the packet-switched network, the adverse effect on the service is particularly obvious. And the method of the second embodiment is adopted, the value of the waterline a is larger than that of the waterline b, and the possibility of errors of the TDM data frame can be greatly reduced at the expense of a small part of time delay, so that the service efficiency is improved.
Example three: two downlink buffers are set.
In the format conversion module of this embodiment, two downlink buffers are provided, which are respectively referred to as a first downlink buffer and a second downlink buffer. And a waterline is not set for the first downlink cache, and a waterline is set for the second downlink cache. The payload is first stored in the first downlink buffer, and when the first downlink buffer reaches the maximum storage capacity, the format conversion module stores the payload stripped from the data packet from the packet switching data processing module into the second downlink buffer, and when the storage capacity of the second downlink buffer reaches the set water line, the flow shown in fig. 2 is triggered.
If the first downlink buffer and the second downlink buffer are regarded as a unified downlink buffer, compared with the first embodiment, except that the storage capacity of the downlink buffer is enlarged, the implementation manner is completely consistent with the first embodiment, except that the downlink buffer extracting and encapsulating the payload in the downlink buffer into the TDM data frame is the first downlink buffer.
When the delay of the packet-switched network is greater than the delay that can be absorbed by one downlink buffer, the embodiment cannot implement the service without adjusting the water line value, and the method of the third embodiment needs to be adopted. Similarly, a plurality of downlink buffers can be arranged, only the last downlink buffer is provided with a waterline, and the TDM data frame packaged by the extracted payload is extracted from the first downlink buffer, so as to adapt to the condition that the packet switching network may have larger time delay.
The first precondition to be satisfied is as follows: the initial water line value is smaller than the upper limit of the capacity of a downlink buffer, and the time delay of the packet switching network is also smaller than the time delay which can be absorbed by the downlink buffer. The third embodiment requires the following preconditions: the initial water line value is larger than the upper limit of the capacity of a downlink buffer, and the time delay of the packet switching network is also larger than the time delay which can be absorbed by the downlink buffer. If neither of these two preconditions is met, the following occurs: the initial water line value is smaller (or larger) than the upper limit of the capacity of a downstream buffer, and the delay of the packet-switched network is larger (or smaller) than the delay that can be accommodated by a downstream buffer, which needs to combine the two cases, which is the fourth embodiment of the present invention.
Example four: a combination of the first and third embodiments.
The format conversion module of this embodiment is the same as that of the third embodiment, and also includes two downlink buffers, which are respectively referred to as a first downlink buffer and a second downlink buffer, where a payload is stored in the first downlink buffer first, and then stored in the second downlink buffer when the capacity of the first downlink buffer reaches the upper limit. The difference lies in that: the water line value can be set in the first downlink cache or the second downlink cache; when the water line value is set in the first downlink cache, the second downlink cache does not actually play a role, and may not be enabled as a standby downlink cache first.
Assume that the initial water line value is located in the first downstream cache. First, the process as in the first embodiment is executed, and when the step 207 is executed and the determination result indicates that the reported information content received this time and the reported information content received last time are both reception errors, the process includes: judging whether the waterline value reaches the upper limit of the capacity of the first downlink cache, if so, starting the second downlink cache, canceling the waterline of the first downlink cache, setting the waterline with the value of 1 in the second downlink cache, and turning to the step 205; otherwise, on the basis of the original waterline, the waterline value is added by 1 and the process goes to step 205. Thus, when the initial water line value is smaller than the upper limit of the capacity of one downlink buffer and the time delay of the packet switching network is larger than the time delay which can be absorbed by one downlink buffer, the water line value can be transferred from the first downlink buffer to the second downlink buffer and finally the ideal water line value is achieved.
If the initial water line value is in the second downlink buffer. First, the process as in the first embodiment is executed, and when the step 207 is executed and the determination result indicates that the contents of the reported information received this time and the contents of the reported information received last time are both correctly received, the process includes: judging whether the water line value reaches the lower limit of the second downlink cache capacity, if so, stopping using the second downlink cache, setting the water line value equal to the upper limit of the first downlink cache capacity in the first downlink cache, and turning to the step 205; otherwise, on the basis of the original waterline, the waterline value is reduced by 1 and step 205 is executed. Thus, when the initial water line value is larger than the upper limit of the capacity of one downlink buffer and the time delay of the packet switching network is smaller than the time delay which can be absorbed by one downlink buffer, the water line value can be transferred from the second downlink buffer to the first downlink buffer and finally the ideal water line value is achieved.
Obviously, the present embodiment can be easily extended to the case of multiple downstream caches. If a plurality of downstream buffers are collectively regarded as one downstream buffer, this embodiment is consistent with embodiment 1 except for a process in which a pipeline is transferred between adjacent downstream buffers. This embodiment can also be easily combined with the solution of the second embodiment. Therefore, the above embodiments and any combination thereof with each other should be within the scope of the present invention.
Referring to the system shown in fig. 1, in order to implement the method embodiment of the present invention, a waterline setting unit, a determining unit, a downlink buffer, and a reporting unit need to be added in the system. Wherein,
the reporting unit is arranged in the TDM processing module 111 and configured to determine a situation that the TDM processing module 111 receives the TDM data frame, and report the situation of receiving the TDM data frame to the water line setting unit.
The waterline setting unit is used for receiving the receiving condition of the TDM data frame from the TDM processing module 111, setting the waterline of the downlink cache according to the receiving condition, and sending the set waterline of the downlink cache to the judging unit;
the judging unit is used for judging whether the payload storage capacity reaches the waterline of the received downlink cache, if so, the format conversion module 112 extracts the payload from the downlink cache, assembles the payload into a TDM data frame and sends the TDM data frame to the TDM processing module 111; otherwise, the format conversion module 112 stores the payload stripped from the packet-switched data packet in the downstream buffer. The judging unit and the waterline setting unit may be sub-modules of the format conversion module, or may be independent modules in the system, or may be control modules described in the embodiments.
Between the waterline setting unit and the judging unit, a waterline converting unit can be further included. The waterline set by the waterline setting unit is called as a first waterline, and the waterline conversion unit converts the first waterline into a second waterline and sends the second waterline to the judgment unit.
The downstream buffer is used to store the payload stripped from the packet-switched data packet, and the downstream buffer may be disposed in the format conversion module 112.
According to the technical scheme, the time delay in the packet switching network can be absorbed by setting the downlink cache for storing the payload; and the waterline of the downlink buffer is adjusted according to the TDM data frame receiving condition fed back by the TDM processing module, so that the time delay absorbed by the downlink buffer is consistent with the time delay actually existing in the packet switching network. Therefore, the embodiment of the invention can effectively control the time delay existing in the process that the payloads from the packet switching network are reassembled into the correct TDM data frame and are sent to the TDM network under the condition that the packet switching network has certain transmission time delay, and reduces the influence of the time delay on the TDM over IP service.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. A method of reducing the effects of latency, in stripping a payload from a packet-switched data packet and encapsulating said payload into a TDM data frame, comprising the steps of:
a1, TDM processing module receives the TDM data frame, judges whether the received TDM data frame is correct, if yes, reports the received TDM data frame as correct, otherwise reports the received TDM data frame as wrong;
a2, judging the reported contents of the current time and the last time, if the reported contents are both correctly received, subtracting 1 from the current waterline value, and executing the step A3;
if the receiving errors are all received, adding 1 to the current water line value, and executing the step A3;
if the current receiving is correct and the last receiving is wrong, turning to the step B;
if the current receiving is wrong and the last receiving is correct, adding 1 to the current water line value and transferring to the step B;
a3, when the payload capacity stored in the downlink buffer is larger than the current waterline value, extracting the payload from the downlink buffer and assembling the payload into a TDM data frame, and sending the TDM data frame to the TDM processing module and turning to the step A1;
B. the payload stripped from the packet switching data packet is stored in the downlink cache;
C. judging whether the payload capacity stored in the downlink cache is larger than the set waterline value, if so, extracting the payload from the downlink cache, assembling the payload into a TDM data frame, sending the TDM data frame to a TDM processing module, and turning to the step B; otherwise, directly turning to the step B.
2. The method of claim 1, wherein the step a1 is preceded by the further steps of: judging whether any one of the following conditions is met, if so, executing the step A1:
performing TDM over IP service initially;
a TDM processing module receives a TDM data frame in the TDM over IP service process and generates errors;
TDM over IP traffic is carried out for a specific period of time.
3. The method of claim 1, wherein if the step a1 is performed for the first time by initiating the TDM over IP service, the step a1 is preceded by further comprising: setting an initial value of a downlink cache water line value;
if step A2 is executed for the first time, step A2 is: and C, judging the reported content, if the reported content is correct, subtracting 1 from the current waterline value, and if the reported content is wrong, adding 1 to the current waterline value and executing the step A3.
4. The method of claim 3, wherein the setting of the initial value of the downlink buffer water line value is: setting an initial value of a waterline value for the nth downlink buffer, wherein n is more than or equal to 1 and less than or equal to M, M is the total number of the downlink buffers, and n and M are integers;
the step a2, where the determination of the current and last reported contents is performed, and if both the reported contents are reception errors, or the first execution of step a2 determines that the current reported contents are reception errors, the method further includes: judging whether the current waterline value reaches the storage upper limit of the nth downlink buffer, if so, canceling the waterline of the nth downlink buffer, setting the waterline value of the (n + 1) th downlink buffer to be 1, and executing the step A3, otherwise, adding 1 to the waterline value and executing the step A3;
if the determination is that the reception is correct, or if the determination in step a2 is performed for the first time, the method further includes: and B, judging whether the current water line value reaches the storage lower limit of the nth downlink buffer, if so, canceling the water line of the nth downlink buffer, setting the water line value of the (n-1) th downlink buffer as the storage upper limit of the (n-1) th downlink buffer, and executing the step A3, otherwise, subtracting 1 from the water line value and executing the step A3.
5. A method of reducing the effects of latency, in stripping a payload from a packet-switched data packet and encapsulating said payload into a TDM data frame, comprising the steps of:
a1, the TDM processing module receives the TDM data frame, judges whether the received TDM data frame is correct, if yes, reports that the receiving is correct, otherwise reports that the receiving is wrong;
a2, judging the current and last reported contents, if both are received correctly, subtracting 1 from the current waterline value, and executing a step a 3;
if the receiving errors are all received, adding 1 to the current water line value, and executing the step a 3;
if the current receiving is correct and the last receiving is wrong, turning to the step b;
if the current receiving is wrong and the last receiving is correct, adding 1 to the current water line value and transferring to the step b;
a3, when the payload capacity stored in the downlink buffer is larger than the current waterline value, extracting the payload from the downlink buffer to assemble into a TDM data frame, and sending the TDM data frame to the TDM processing module and turning to the step a 1;
b. determining a second water line value according to the determined current water line value, namely a first water line value, and a preset corresponding relation between the first water line value and the second water line value, wherein the first water line value is larger than the second water line value;
c. the payload stripped from the packet switching data packet is stored in the downlink cache;
d. judging whether the payload capacity stored in the downlink cache is larger than the second water line value, if so, extracting the payload from the downlink cache, assembling the payload into a TDM data frame, sending the TDM data frame to a TDM processing module, and turning to the step c; otherwise, go to step c directly.
6. A system for reducing time delay influence comprises a TDM processing module and a format conversion module, wherein the format conversion module is used for stripping payload from a packet switching data packet, assembling the payload into a TDM data frame and sending the TDM data frame to the TDM processing module;
the downstream cache with the set waterline is used for storing the payload stripped from the packet switching data packet;
the waterline setting unit is used for receiving the condition information of receiving the TDM data frames from the TDM processing module, judging the current and last reported contents, and subtracting 1 from the current waterline value if the receiving is correct; if the data are all reception errors, adding 1 to the current water line value; if the current receiving is wrong and the last receiving is correct, adding 1 to the current water line value; sending the set waterline of the downlink cache to the judging unit; if the current receiving is correct and the last receiving is wrong, keeping the current water line value unchanged;
the judging unit is used for judging whether the storage capacity of the payload reaches a waterline of the received downlink cache, if so, the format conversion module extracts the payload from the downlink cache and assembles the payload into a TDM data frame to be sent to the TDM processing module; otherwise, the format conversion module stores the payload stripped from the packet switching data packet in the downlink cache;
the TDM processing module comprises a reporting unit which is used for generating the condition information of the received TDM data frame and reporting the condition information of the received TDM data frame to the water line setting unit.
7. The system of claim 6, wherein the downstream buffer comprises M sub-buffers, wherein the mth sub-buffer is used to store a new payload when the (M-1) th sub-buffer has reached an upper storage limit, and wherein 1 < M ≦ M.
8. The system of claim 6, wherein the downstream buffer is disposed in a format conversion module.
9. The system of claim 6, wherein the waterline setting unit and/or the determining unit are disposed in a format conversion module.
10. The system of claim 6, 7 or 8, further comprising a waterline conversion unit that takes the waterline from the waterline setting unit as a first waterline, converts the first waterline into a second waterline having a determined functional relationship with the first waterline, and sends the second waterline to the determination module.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1614967A (en) * | 2003-11-06 | 2005-05-11 | 华为技术有限公司 | Minimum time delay adjusting method for reversed multiplexing agreement in asychronous transmitting mode |
| CN1798086A (en) * | 2004-12-29 | 2006-07-05 | 中兴通讯股份有限公司 | Method of transmission control for adaptation layer 2 in asynchronous transfer mode |
| CN1859077A (en) * | 2005-04-30 | 2006-11-08 | 华为技术有限公司 | Time division multiplex data transmitting method based on packet exchanging |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1614967A (en) * | 2003-11-06 | 2005-05-11 | 华为技术有限公司 | Minimum time delay adjusting method for reversed multiplexing agreement in asychronous transmitting mode |
| CN1798086A (en) * | 2004-12-29 | 2006-07-05 | 中兴通讯股份有限公司 | Method of transmission control for adaptation layer 2 in asynchronous transfer mode |
| CN1859077A (en) * | 2005-04-30 | 2006-11-08 | 华为技术有限公司 | Time division multiplex data transmitting method based on packet exchanging |
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