JP2008078770A - Data signal transfer method and transceiving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data signal transfer method and a transceiving device, which allow a plurality of operation modes for selecting early arriving frames/discarding late arriving frames, synchronizing and selecting frames, etc. to be easily switched. <P>SOLUTION: With respect to switching between the operation modes, priorities are defined to a plurality of paths, and these priorities are set to transfer frames sent to respective paths, and a reception side selects a down transfer frame (to a client side) in accordance with the priorities, whereby the same operation as selecting early arriving frames/discarding late arriving frames is performed when higher priorities are given to paths having shorter delay, and an operation of synchronizing transfer frames having identical information from the plurality of paths, with each other to select one transfer frame to the client side (synchronizing and selecting) is performed when higher priorities are given to paths having longer delay. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transfer control technique for transferring a client data signal in a network.

  In the conventional high reliability technology in packet communication, for example, as disclosed in Patent Document 1, an order identifier is inserted into a packet, duplicated and transmitted to a plurality of paths, and an order identifier that arrives from each path is received on the receiving side. There is a method of determining the order by checking and transferring the early arrival packet downstream.

  This method has a feature that even if a packet fails to reach due to a route failure or the like, if any one of a plurality of routes is normal, communication without packet loss is possible.

  Patent Document 2 describes a method of sending ATM cell frames to a plurality of paths and selecting them on the receiving side. The receiving side determines the delay difference between the plurality of paths, and based on the same, arrives from the plurality of paths. By adjusting the delay difference of ATM cell frames having information, there is a feature that transmission without interruption due to loss of ATM cell frames is realized even when the fluctuation of transmission delay is large.

JP 2005-102157 A Japanese Patent No. 3484083

  The method of the above-mentioned patent document 1 and the method of the above-mentioned patent document 2 are the same in the operation mode in which early arrival selection / late arrival discarding is performed, respectively, and the transfer frame having the same information arriving from a plurality of routes is synchronized. The operation mode to be selected (synchronous selection) is shown.

  The method and apparatus to be used (transmission apparatus, reception apparatus, relay apparatus, etc.) is determined depending on which mode is desired according to the request condition of the client. That is, when the data signal of the client is strict with the absolute value of the transmission delay, the method of Patent Document 1 that performs early arrival selection / delay discard is aimed at. In this case, during normal operation, a frame arriving from a path with a small transmission delay is always transferred downstream, but if a frame does not arrive from a path with a small transmission delay due to a path failure or the like, , The frame reception time jumps in that case.

  Therefore, when the data signal of the client is severe in frame transfer continuity, the method of Patent Document 2 is aimed. However, in this case, since the delay difference adjustment always occurs, the absolute value of the transmission delay naturally increases.

  As described above, in the prior art, since the application method and apparatus differ depending on the requirements of the client data signal, it is difficult to apply various clients to the same apparatus. In order to change these two operation modes, it is necessary to change the hardware and software settings in advance.

  On the other hand, nowadays, the network transmission band for transferring client data signals can be set to 10 Gbit / s or more, and dealing with various clients with the same device is cost and operability of the device. This is an important issue.

  The present invention has been made under such a background, and provides a data signal transfer method and transmission / reception apparatus in which a plurality of operation modes such as early arrival selection / late arrival discard or synchronous selection can be easily changed. The purpose is to provide.

  In the present invention, with regard to the change of the operation mode, priority is defined for a plurality of routes, this priority is set for a transfer frame transmitted to each route, and the downstream side (client side) according to the priority on the receiving side When the priority of a route with a small delay is increased by selecting a transfer frame to the network, the same operation as the early arrival selection / delay discard is performed, and when the priority of a route with a large delay is increased. The operation mode can be easily changed, such as performing an operation of synchronizing one transfer frame having the same information from a plurality of paths and transferring one to the client side (synchronous selection). .

  That is, the present invention is a data signal transfer method, wherein at least two or more independent paths (hereinafter referred to as independent paths) are set between transmission and reception in a network for transferring a client data signal. The transfer frame in the network is duplicated on the transmission side and transferred to each of the independent paths, and the transmission side transfers an order identifier or a time stamp for identifying the order of the transfer frames. Described in the frame, and on the receiving side, by referring to the sequence identifier or time stamp described in the transfer frame received from the independent path, the transfer frame having the same information among the transfer frames and the sequence thereof are determined. This is a data signal transfer method to be recognized.

  Here, a feature of the present invention is that a plurality of the independent paths or a plurality of transfer frames having the same information transferred to the independent paths have different priorities, and the receiving side The data signal of the transfer frame having a high priority and normal is immediately transferred to the client side, the frame having the same information with the low priority is discarded, and the transmission delay of the path through which the transfer frame with the low priority passes is If it is smaller than the other paths, this transfer frame is made to wait and the delay difference from the frame having the same information having a high priority is adjusted.

  For example, the priority is set based on the transmission delay of the independent path. At this time, depending on whether a route with a higher transmission delay is set as a route with a higher priority, or a route with a lower transmission delay is set as a route with a higher priority, the earlier arrival selection / delay described above. An operation mode of discard / discard or synchronization selection can be selected.

  At this time, when the transmission delay of the route is known in advance, the priority may be determined in advance for each route. Further, when the transmission delay of the route is unknown or when the transmission delay of the route changes every moment, the transmission delay of the route may be measured in real time by examining the delay difference in the plurality of routes. In this case, only the policy for setting the priority, such as how to set the priority according to the transmission delay, is determined in advance.

  Alternatively, a priority identifier of the transfer frame can be given to the transfer frame on the transmission side. According to this, since the priority can be set for each transfer frame regardless of the transmission delay of the path and other factors of the transmission environment, for example, early arrival selection / late arrival discard or synchronization for each data signal type The operation mode of selection can be selected.

  Further, for example, the delay adjustment amount of the transfer frame arriving from a plurality of the independent paths is set based on the transmission delay difference of the independent paths.

  Further, when the present invention is viewed from the viewpoint of the transmission apparatus, the present invention includes a means for duplicating the transfer frame, and an order identifier or a time for identifying the order of the transfer frame for each transfer frame duplicated by the duplication means. A transmission apparatus comprising means for assigning a stamp and means for sending each transfer frame assigned an order identifier or time stamp to the plurality of independent paths by the assigning means, and a feature of the present invention This is because a means for assigning a priority identifier of the transfer frame to the transfer frame is provided.

  Further, when the present invention is viewed from the viewpoint of a receiving apparatus, the present invention refers to a transfer frame having the same information among the transfer frames by referring to an order identifier or a time stamp of the transfer frame received from an independent route. A receiving apparatus comprising means for recognizing the order, the feature of the present invention is that a plurality of the independent paths or a plurality of the same information transferred to the independent paths include Different priority levels are defined, data signals of high-priority and normal transfer frames are immediately transferred to the client side, frames having the same information with lower priority are discarded, and transfer frames with lower priority pass. If the transmission delay of the selected route is small compared to other routes, this transfer frame is waited and the same information with a high priority is held. There is to provided with a means for adjusting the delay difference between that frame.

  In addition, the said independent path | route is an at least 2 or more independent path | route which does not interrupt communication simultaneously by a single failure or construction. Further, the part describing the sequence identifier or the time stamp is defined as a field for order identification defined in the header of the transfer frame or an extension field whose usage is not defined or a field that can be inserted into the transfer frame Field, etc.

  According to the present invention, it is possible to easily select early arrival selection / delay discard and synchronization selection, and it is possible to provide a highly reliable network without data loss.

(First Example)
The communication system of the first embodiment will be described with reference to FIGS. FIG. 1 is a configuration diagram of a communication system according to the first embodiment. In the first embodiment, the user sets a priority in advance for each route. In the priority registration unit 6, priority information for each route preset by the user is registered.

  The copy unit 1 duplicates the input packet, and the order identifier assigning unit 2 assigns the same order identifier to the plurality of duplicated packets and sends them to a plurality of routes.

  The delay difference determination unit 3 determines a frame having the same information among frames arriving from a plurality of paths according to the sequence identifier and the time stamp, and determines a delay difference between transfer frames having the same information.

  When the priority of the route with the smaller delay is set higher, if the frame arrives from the route with the smaller delay, the data signal is immediately transferred to the client side, and the same information is transmitted from the route with the larger delay. When the frame arrives, discard it.

  When the priority of the route with the smaller delay is set low, the transfer frame of the route with the smaller delay is kept waiting for the time corresponding to the delay difference and has the same information from the route with the larger delay. After waiting for the arrival of the transfer frame, the delay difference adjustment unit 4 adjusts so as to eliminate the delay difference between the two frames, and then the frame selection unit 5 selects only one normal frame from the two frames and outputs the data signal. To the client side. The frame not selected is discarded.

  Next, the processing procedure of the first embodiment will be described with reference to FIG. FIG. 2 is a flowchart showing the processing procedure of the first embodiment. Here, the case where the number of independent paths is 2 is shown, and the A system and the B system are used. In addition, the priority of the A system is higher than that of the B system. As a processing procedure on the reception side, first, the presence / absence of an arrival frame having a higher priority (A system in the example) is confirmed (S1), and if there is, an order comparison is performed (S2, S3).

  If the order CA of the transfer frames is equal to or less than the counter value CF held on the receiving side (CF ≧ CA), the transfer frame can be recognized as an already-arrived transfer frame and is discarded (S4).

  If CF + 1 = CA, it can be recognized that the transfer frame should arrive next, and the A system has the higher priority, so the data signal of the transfer frame is immediately transferred downstream (S5).

  If CA is larger than CF + 1 (CF + 1 <CA), it is possible to wait for a transfer frame in the buffer of the delay difference adjustment unit 4 and wait for a frame whose order corresponds to CF + 1. In this case, the waiting time can be set in advance, and when the order waiting time is not completed (S6), the data signal of the A-system transfer frame waits (S7). On the other hand, when the order waiting time has expired (S6), the data signal of the A-system transfer frame is transferred downstream (S5).

  In the example of FIG. 2, after processing a transfer frame (A-system transfer frame) of a route with a high priority, the process proceeds to a transfer frame (B-system transfer frame) of a route with a low priority. In the B system, as in the A system, the presence / absence of a transfer frame is confirmed (S8), and if it exists, the order is compared (S9, S10). If the transfer frame order CB is less than or equal to the counter value CF held on the receiving side (CF ≧ CB), the transfer frame can be recognized as an already-arrived transfer frame and is discarded (S11).

  If CF + 1 = CB, it can be recognized that the frame is a transfer frame including a data signal to be transferred next downstream, but at this point, the order of CF is one smaller than CB indicates that A having a high priority Since the CF + 1 transfer frame has not arrived in the system, an operation of waiting for arrival from the A system is performed without immediately transferring the B system transfer frame having a low priority.

  If the other system arrival waiting time is set in advance and the time is not completed (S13), the B system transfer frame waits (S14), and the process returns to the confirmation of the A system transfer frame. On the other hand, if the other system arrival waiting time expires (S13), the B system transfer frame is transferred (S12).

  When CB is larger than CF + 1 (CF + 1 <CB), CB and CA are compared (S15). If CB is greater than or equal to CA (CA ≦ CB), the B-system transfer frame waits as it is (S14) and returns to the confirmation of the A-system transfer frame.

  When CB is smaller than CA (CA> CB), the data signal of the B-system transfer frame is transferred downstream only when both the other system arrival waiting time and the order waiting time have expired. (S16, S17). In all other cases, the B-system transfer frame waits and returns to the confirmation of the A-system transfer frame.

  In this example, after confirming the transfer frame from the route with high priority and performing the processing, the flowchart to shift to the processing of the transfer frame of the route with low priority was shown. It is also possible to perform the method of identifying the order and identifying the priority. Thus, the transfer frame processing procedure in the present invention is not limited to that shown in this embodiment.

(Second embodiment)
A communication system according to the second embodiment will be described with reference to FIG. FIG. 3 is a block diagram of the communication system of the second embodiment. In the second embodiment, the delay difference determination unit 3 determines the transmission delay difference of the transfer frame and sets the priority according to the delay difference. The priority with the smaller delay can be set higher, or the priority with the larger delay can be set.

  In the priority setting unit 7, a priority according to the delay is set in advance by the user. If the priority with the smaller delay is set higher, if the frame arrives from the smaller delay, the data signal is immediately transferred to the client side, and if the same information frame arrives from the larger delay, it is Discard.

  If the priority with the smaller delay is set low, the transfer frame with the smaller delay is kept waiting for the time corresponding to the delay difference, and the arrival of the transfer frame with the same information from the larger delay is waited. After adjusting the delay difference adjustment unit 4 so as to eliminate the delay difference between the two frames, the frame selection unit 5 selects only one normal frame from the two frames and transfers the data signal to the client side. . The frame not selected is discarded.

  Other processing procedures are the same as those in the first embodiment, and thus the description thereof is omitted.

(Third embodiment)
A communication system according to a third embodiment will be described with reference to FIGS. FIG. 4 is a block diagram of the communication system of the third embodiment. In the third embodiment, priority is set for each transfer frame by the priority identifier assigning unit 8 on the transmission side, and the priority determination unit 9 on the reception side reads the priority identifier assigned for each transfer frame. , Identify the priority.

  Next, the processing procedure of the third embodiment will be described with reference to FIG. FIG. 5 is a flowchart showing the processing procedure of the third embodiment. When there are transfer frames from the A system and the B system (S20), the priority determination unit 9 reads the priority identifier from the transfer frames of the A system and the B system (S21), and compares the priorities (S22). .

  If the priority level can be discriminated, first, the transfer frame processing procedure with higher priority (steps S3 to S7 in FIG. 2) described in the first embodiment is executed (S23), and then the first embodiment. The transfer frame processing procedure with the lower priority described in the example (steps S10 to S17 in FIG. 2) is executed (S24).

  When there is a transfer frame only from either the A system or the B system (S20), the priority determination unit 9 reads the priority identifier from the transfer frame (S25), and refers to the priority identifier. Accordingly, the priority given to the transfer frame is recognized, and when the priority is high, the transfer frame processing procedure with the higher priority described in the first embodiment (steps S3 to S3 in FIG. 2). S7) is executed (S27). When the priority is low, the transfer frame processing procedure (steps S10 to S17 in FIG. 2) with the lower priority described in the first embodiment is executed (S28).

(Fourth embodiment)
A fourth embodiment will be described with reference to FIGS. 6 to 9 are block configuration diagrams of the transmission apparatus of this embodiment. The fourth embodiment is an embodiment of the transmission apparatus, and describes the transmission apparatus shown in FIGS. 1, 3, and 4 in more detail.

  In the configuration example of FIG. 6, the data signal is received by the receiving unit 10, and a transfer frame having the data signal received by the framing unit 11 in the payload area is generated. This transfer frame is duplicated by the copy unit 1, and an order identifier or priority identifier is assigned to each of the transfer frames duplicated by the two identifier assigning units 20-1 and 20-2. The transfer frame duplicated by the two transmission units 12-1 and 12-2 and given the order identifier or the priority identifier is transmitted toward the reception side.

  In the configuration example of FIG. 7, a data signal is received by the receiving unit 10, and a transfer frame having the data signal received by the framing unit 11 in the payload area is generated. The identifier assigning unit 20 assigns an order identifier or priority identifier to the transfer frame. The transfer frame is duplicated by the copy unit 1, and the transfer frame duplicated by the two transmission units 12-1 and 12-2 and given the order identifier or the priority identifier is transmitted to the reception side.

  6 and 7 both generate a transfer frame having a data signal in the payload area by the framing unit 11, but when the data signal itself already has a configuration as a transfer frame, As shown in FIGS. 8 and 9, the framing unit 11 can be omitted.

  Further, in the configuration examples of FIGS. 6 to 9, the function of the order identifier assigning unit 2 and the priority identifier assigning unit 8 is shared by a single identifier assigning unit 20. Easy to analogize.

(Fifth embodiment)
A fifth embodiment will be described with reference to FIG. FIG. 10 is a block diagram of the receiving apparatus of this embodiment. The fifth embodiment is an embodiment of the receiving apparatus, and describes the receiving apparatus shown in FIGS. 1, 3, and 4 in more detail.

  The transfer frames transmitted from the transmission device are received by the receiving units 30-1 and 30-2 and accumulated in the buffer 31-1 as the memory-A and the buffer 31-2 as the memory-B, respectively.

  The delay difference determination unit 3 in FIGS. 1, 3, and 4 can be realized by the control unit 32 examining the time difference when the transfer frames having the same order information arrive at the buffers 31-1 and 31-2. .

  The delay difference adjustment unit 4 also determines the transfer frame buffers 31-1 and 31 based on the arrival time difference of the transfer frames having the same order information checked by the control unit 32 to the buffers 31-1 and 31-2. -2 can be realized by adjusting the read timing from -2.

  Further, the frame selection unit 5 is configured such that the control unit 32 confirms the normality of the transfer frames stored in the buffer 31-1 and the buffer 31-2, and the normality of one of the transfer frames is confirmed. Can be realized by reading the transfer frame from the buffer 31-1 or 31-2 and discarding the transfer frame whose normality has not been confirmed from the buffer 31-1 or 31-2. When the normality of both transfer frames is confirmed, one predetermined transfer frame is read and the other is discarded.

  Moreover, the control part 32 can have the function of the priority registration part 6, the priority setting part 7, and the priority determination part 9. FIG. Furthermore, in order to execute the processing procedure that each unit cooperates to execute, as in the processing procedure of the flowchart of FIG. 2 or FIG. 5, the control unit 32 and the counter unit 33 cooperate, The value can be realized by setting the value corresponding to CF and CF + 1 in the flowchart of FIG. 2 or FIG.

  According to the present invention, early arrival selection / delayed discard and synchronous selection can be easily selected, and a highly reliable network without data loss can be realized. Therefore, convenience for network users can be improved. At the same time, it is not necessary for the network operator to prepare a plurality of data signal transfer methods and devices, and efficient network operation can be realized.

The block diagram of the communication system of a 1st Example. The flowchart which shows the process sequence of the communication system of a 1st Example. The block diagram of the communication system of a 2nd Example. The block diagram of the communication system of a 3rd Example. The flowchart which shows the process sequence of the communication system of a 3rd Example. The block block diagram of the transmission apparatus of 4th Example (the 1). The block block diagram of the transmission apparatus of 4th Example (the 2). The block block diagram of the transmission apparatus of 4th Example (the 3). The block block diagram of the transmission apparatus of 4th Example (the 4). The block block diagram of the receiver of 5th Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Copy part 2 Order identifier provision part 3 Delay difference determination part 4 Delay difference adjustment part 5 Frame selection part 6 Priority registration part 7 Priority setting part 8 Priority identifier provision part 9 Priority determination part 10 Reception part 11 Framing part 12-1, 12-2, 34 Transmitting unit 20, 20-1, 20-2 Identifier assigning unit 30-1, 30-2 Receiving unit 31-1, 31-2 Buffer 32 Control unit 33 Counter unit

Claims (6)

Between the transmission and reception in the network for transferring the data signal of the client, it is made redundant by setting at least two independent paths (hereinafter referred to as independent paths),
Transfer frames in the network are duplicated on the transmission side and then transferred to each of the independent paths,
On the transmission side, an order identifier or time stamp for identifying the order of the transfer frames is described in the transfer frame,
On the receiving side, by referring to the sequence identifier or time stamp described in the transfer frame received from the independent path, the transfer frame having the same information among the transfer frames and the data signal transfer for recognizing the sequence In the method
Different priority is defined for each of the plurality of independent paths or the plurality of transfer frames having the same information transferred to the independent paths,
On the receiving side, the data signal of the transfer frame having a high priority and normal is immediately transferred to the client side, and the frame having the same information with a low priority is discarded.
If the transmission delay of the path through which the low-priority transfer frame passes is smaller than that of other paths, this transfer frame is waited to adjust the delay difference from the frame having the same information with high priority. A data signal transfer method.   The data signal transfer method according to claim 1, wherein the priority is set based on a transmission delay of the independent path.   The data signal transfer method according to claim 1, wherein an identifier of a priority of the transfer frame is assigned to the transfer frame on the transmission side.   The data signal transfer method according to claim 1, wherein a delay adjustment amount of the transfer frame arriving from a plurality of independent paths is set based on a transmission delay difference of the independent paths. Means for duplicating the forwarding frame;
Means for giving an order identifier or time stamp for identifying the order of the transfer frames to each transfer frame copied by the means for copying;
A transmission device comprising: means for transmitting each of the transfer frames assigned with an order identifier or a time stamp to the plurality of independent paths by the means for giving,
A transmission apparatus comprising: means for assigning a priority identifier of the transfer frame to the transfer frame. In a receiving apparatus comprising means for recognizing a transfer frame having the same information among the transfer frames and a sequence thereof by referring to an order identifier or a time stamp of the transfer frame received from an independent path,
Different priority is defined for each of the plurality of independent paths or the plurality of transfer frames having the same information transferred to the independent paths,
A data signal of a high-priority and normal transfer frame is immediately transferred to the client side, and the frame having the same information with a low priority is discarded.
When a transmission delay of a path through which a transfer frame having a low priority passes is smaller than that of other paths, means for waiting for the transfer frame and adjusting a delay difference from the frame having the same information having a high priority A receiving apparatus comprising:

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