JPH06343081A - Data transfer system - Google Patents

Abstract

PURPOSE:To reduce the generation of congestion and to reduce the spreading effect at the time of generation of congestion to a minimum by providing an area storing a group of an exchange station number, a repeating line number in an information frame and an area showing whether or not the contents of the area is used. CONSTITUTION:When congestion is generated in a repeating line 13 connected to an exchange station 6, a notification means 14 of an exchange station 4 which receives the notification of the congestion notifies the number of a repeating line where the congestion is generated to a monitor 15. Upon receipt of the notification the monitor 15 judges the repeating line belongs to a fixed route and a detection means 16 detects the generation of the congestion in the fixed route and notifies it to a copy means 17. The information frame is copied by the means 17 and sent to the only repeating line 11. In this case, the exchange station number 4 and the repeating line 11 are stored in the TR area of the information frame and the area S is set to be present with a designation S. An incoming signal 5 receives a frame and only one frame is made effective if the flow occurs from plural fixed routes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transfer system for delivering data to be transferred from a calling side to a called side in a communication network such as packet communication in which data is stored in a frame and transferred. .

[0002]

2. Description of the Related Art Conventionally, in a packet type communication network, a plurality of fixed routes are set between two stations respectively accommodating terminals for data communication, and a plurality of data from a terminal on the transmitting station side are copied at the transmitting station. There is a data transfer method in which an information frame for the copy is created, and the created information frame is transmitted simultaneously for each of a plurality of fixed routes. As a data transfer method for discarding duplicated information frames and controlling the order at the receiving station, for example, X. There are 75 multi-link procedures. In this procedure, data transfer is performed using a SLP procedure for each of a plurality of routes connecting the two stations. Further, when transmitting data entering the network from the terminal to the network, the most data is copied by the number of SLPs (for example, three SLPs are tripled).

[0003]

In the conventional method, there is a possibility that congestion may occur because there is no means for suppressing the increase in the number of frames in the network due to copying. Further, once congestion occurs, there is a problem that the control frame in the network for avoiding the congestion is also copied and the congestion is spread.

The present invention was conceived in order to solve the above-mentioned problems, and it is possible to suppress the occurrence of congestion and to minimize the ripple effect at the time of occurrence of congestion. The purpose of the present invention is to obtain a data transfer method that reduces the number of copy frames.

[0005]

According to a first aspect of the present invention, there is provided a data transfer system, wherein a plurality of fixed paths are set between two stations respectively accommodating terminals for performing data communication, and data from a terminal on the transmitting station side is set. In the data transfer method, the sending station creates multiple copies of the information frame for each copy and sends one for each fixed route at the same time, and the receiving station discards duplicate information frames and controls the order in the data transfer method. By providing an area (TR area) for storing a set of switching center numbers and trunk line numbers and an area (S area) indicating whether or not to utilize the contents of the TR area in the frame, the TR area of each station Data was transferred by updating and setting the S area at the transmitting station. That is, an area (TR) for storing a set of station numbers and trunk line numbers in the information frame.
Area) and an area (S area) indicating whether or not to utilize the contents of the TR area are set, the TR area and the S area are set at the transmitting station, the TR area is updated at the relay station, and the receiving station is set. , The number of copy frames of the delivery confirmation frame for the information frame is limited based on the S area.

A data transfer system according to a second aspect of the present invention is, in the above-mentioned data transfer system, a notification means for notifying each station of all stations other than its own station, and a fixed means from the notified traffic state of each station. Monitoring means for monitoring the traffic for each route, detection means for detecting a congestion fixed route from the traffic data, and when congestion of the fixed route is detected, information frames are not transmitted to the fixed route where congestion occurs In addition to the above, a copy means for setting the S area of the information frame is provided, and a delivery confirmation frame from a route in which no congestion has occurred is expected.

A data transfer system according to a third aspect of the present invention is characterized in that, in the data transfer system, the S area is fixedly set for a specific type of frame.

In the data transfer method according to the fourth aspect of the present invention, in the above data transfer method, the transmitting station sets the S area of the copy frame to be transmitted to all fixed routes, and the receiving station discards duplicate information frames. It is characterized in that the frame is returned for all the copy frames without carrying out.

In the data transfer system according to the fifth aspect of the invention, a plurality of fixed routes are set between two stations respectively accommodating terminals for data communication, and a plurality of data from the terminal on the transmitting station side are copied at the transmitting station. To create an information frame for each copy, send the created information frame one by one for each fixed route, and set a set of information frames in the information transfer system in the receiving station that discards duplicate information frames and controls the order. The area (TR area) for storing the minute station number and the trunk line number and the area (T area) for storing the transmission time are provided.
At the calling station, the time at which the call originated is set in the T area, and based on the time set in the T area at the called station, it is detected that the elapsed time in the network has reached a value that is equal to or greater than the prespecified network parameter. By doing so, it is determined that congestion has occurred in the fixed route, and the number of delivery confirmation frames is suppressed.

[0010]

The data transfer method according to the present invention can suppress the number of frames to be copied in the network by setting the S area or the T area. In addition, the number of copies can be restricted for each type of frame, and the restrictions can be changed dynamically depending on the load condition of the network. Even though copying is performed, the network load is low and highly reliable data transfer is possible. Is possible.

[0011]

【Example】

Example 1. Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is an area (TR area) for storing a pair of switching center numbers and trunk line numbers in an information frame with a pair of switching center numbers and trunk line numbers as a pair, and 2 is the T
An area (S area) indicating whether or not to utilize the contents of the R area,
Reference numeral 3 denotes an area (T area) for storing the time at which the transmitting station creates and transmits a copy frame.

FIG. 2 is a diagram showing an example of a network to which the frame format of FIG. 1 is applied. 4 to 6 are exchanges. In this example, 4 is a transmitting station, 5 is a receiving station, and 6 is a relay station. 7 to 8 are communication terminals, 9 to 10 are terminal lines connecting the exchange 4 and the communication terminal 7, respectively, and the exchange 5
Terminal lines 11 to 13 for connecting the communication terminal 8 and the communication terminal 8 are respectively the exchange 4 and the exchange 5, the exchange 4 and the exchange 6, and the exchange 5 respectively.
And a switching line connecting the exchange 6 and the switching center 6, 14 is a notifying means for notifying the congestion state of the own station and the congestion state of the connected relay line to all stations other than the own station by an in-network control frame or the like, 15
Is a monitoring unit that collects the congestion information notified from the notification unit 14 of each exchange, collects the congestion information into information as a fixed route, and monitors the state of each of a plurality of fixed routes, and 16 is a monitoring unit 1.
Detecting means for detecting a fixed route in which congestion has occurred from the information monitored by 5, and 17 makes a plurality of copies of the data from the terminal on the transmitting station side to create an information frame for the copies, and for each of the plurality of fixed routes It is a copying means that simultaneously transmits one by one, and does not make a copy of the fixed route in which the congestion is detected by the detecting means 16 and does not make a transmission.

In the description of the embodiment, as shown in FIG. 3 for simplification, only the communication from the exchange 4 to the exchange 5 will be described. Furthermore, the fixed route used in the communication is 18
And 19 only. However, it is premised that the transmission of the delivery confirmation frame and the retransmission request frame is in the opposite direction, that is, that there is communication from the exchange 5 to the exchange 4, and the fixed routes at that time are two, 18 and 19.

Next, terms used in this embodiment will be described. (1) Type of frame Information frame: Frame that carries user information Delivery confirmation frame: Frame that notifies the information frame from the receiving side to the sending side Resend request frame: Information frame from the receiving side to the sending side Frame for requesting retransmission (2) Switching center number: Unique number assigned to switching center (3) Relay line number: Unique number assigned to relay line between switching centers (4) TR area: Exchange of one set in frame Area for storing station number and relay line number (see FIG. 4) Information is written in the originating station and relay station of the frame. The situation is indicated by symbols as follows. TR (switching station number, relay line number) For example, as shown in FIG. 4, the relay station with the switching center number 2 that receives the information frame having TR (1, 10) has the frame from the switching center number 1 to the relay line. It is possible to know that the call has been made via the number 10. (5) S area: an area indicating whether or not to utilize the contents of the TR area. This area is used for transmitting when, for example, the transmitting station of the information frame wants to limit the number of delivery confirmation frames from the receiving station to one. This is an area where utilization is displayed at the station (for example, if the bit is supported, bit ON, etc.) In the relay station, the S area is left unchanged and only the TR area is updated as shown in FIG. T
The R area is overwritten by the relay station. In the receiving station, when the S area is valid, when the delivery confirmation frame is created and returned, the transmission is made only to the relay line number 20 without copying. In this way, when there is a display to be utilized (for example, when the bit is supported and the bit is ON), copying is not performed, and one frame is sent only to the trunk line shown in the TR area. On the other hand, when there is no display to be utilized (for example, when the bit is supported and the bit is OFF), copying is performed for all the relay lines, and one frame is sent to each relay circuit. In this embodiment, when there is a display to be utilized, it is referred to as S designation, and when there is no display to utilize, it is referred to as S non-designation. (6) T area: area for storing time at the time of frame transmission Information is written at the frame transmission station and relay station. The receiving station of the frame calculates the delay time in the network by comparing it with its own time, and when the value exceeds the prespecified network parameter, for example, a delivery confirmation frame using the relay line Stop sending.

Next, the operation of each switching center in a normal state, that is, the state in which the fixed route congestion is not detected by the detecting means 16 will be described with reference to FIG. The information frame that has entered the exchange 4 from the terminal 7 through the terminal line 9 is copied by the copying means 17 for the fixed route 18 and the fixed route 19 and is transmitted to the relay lines 11 and 12. At this time, in the TR area of each copied information frame, for the frame 20 transmitted to the relay line 11, 4 is stored as the exchange number and 11 is stored as the relay line number, and the frame 21 transmitted to the relay line 12 is stored. , 4 is stored as the switching center number and 12 is stored as the trunk line number, and the value is set so that the S area 2 indicates that the TR area is utilized. Further, the T area 3 is also copied, and the time of transmission (here, 10:00:00) is stored.

In the relay station 6, the frame 21 received from the relay line 12 is stored in the S area as it is, the TR area is stored by overwriting 6 as the exchange number and 13 as the relay line number, and the T area is left as it is and relayed. To do. The receiving station 5 receives the frames 20 and 22. In this example, it is assumed that the frame 20 is validated and the frame 22 is discarded by discarding the duplicate frame. For the finally valid frame 20, the terminating station 5 further creates a delivery confirmation frame for confirming delivery of the frame based on the frame 20. Since it is shown that the frame 20 uses the TR area in the S area, the delivery confirmation frame 23 does not perform the copy operation, and transmits only to the fixed route 18 (11 as a relay line). This state is shown in FIG.

The case where S is specified has been described above, but the sequence diagram of FIG. 7 shows what happens when compared with the case where S is not specified. If S is not specified,
As the delivery confirmation frame, a delivery confirmation frame 23 and a delivery confirmation frame 24 are transmitted to two fixed routes 18 and 19 (relay lines 11 and 13), respectively. The delivery confirmation frame 24 becomes a delivery confirmation frame 25 at the exchange 6 and reaches the exchange 4. In addition, S designation of the delivery confirmation frame is always S non-designation.

Next, an operation of detecting congestion of a fixed path,
The operation of each exchange at that time will be described. As an operation for detecting congestion on a fixed route, a method may be considered in which the switching center is provided with both the notification means 14, the monitoring means 15, and the detection means 16. The time calculated by comparing the time in the T area of the information frame received at the called station with the time held by the called station is compared with the delay parameter value in the network determined in advance by the network, and the calculated time is There is a method that defines a large state as congestion detection.

First, an embodiment of the former method will be described. The transmitting station collects the congestion state of each switching station and the relay line of the switching station notified from the notification means 14 provided in each switching station. This congestion state is collected by the monitoring means 15 as fixed route information and is monitored as a fixed route state. Consider a case where congestion occurs in the trunk line 13 connected to the exchange 6. The notification means 14 of the exchange 4 which has received the notification of the congestion state notifies the monitoring means 15 of the number of the trunk line in which the congestion has occurred. In response to this, the monitoring means judges that the relay line belongs to the fixed path 19, the detection means 16 detects that congestion has occurred in the fixed path 19, and notifies the copy means 17.

The information frame that has entered the exchange 4 from the terminal 7 through the terminal line 9 is copied only to the fixed route 18 by the copying means 17 and is transmitted only to the relay line 11. At this time, the exchange area number 4 and the trunk line number 11 are stored in the TR area of the information frame, and the S area 2 is set to have S designation. Further, the time at that time (10:00:00) is stored in the T area 3. The state is no different from the state in which only the frame 20 is transmitted in FIG.

The receiving station 5 receives the frame 20 and carries out the duplicate frame discarding process as in the normal case. In this example, there are only two fixed routes, and since one route is not sent due to congestion, frame discard processing does not actually work, but if there are inflows from multiple fixed routes, it will be as usual. Discarding is performed and only one frame is valid. In addition to the frame 20, the receiving station 5 sends a delivery confirmation frame for confirming delivery of the frame to the frame 2
Create based on 0.

Since the frame 20 has the S designation, the delivery confirmation frame 23 does not perform the copying operation, and transmits the delivery confirmation frame only to the fixed route 18 (11 as the relay line). This state is as shown in FIG. In this way, the transmitting station 4 can receive the delivery confirmation frame from the fixed route in which no congestion occurs.

Next, an example of the latter method will be described. At the transmitting station, there is no special additional processing as compared with the normal time, and the information frame that has entered the exchange station 4 from the terminal 7 through the terminal line 9 is transferred by the copying means 17 to the fixed path 1.
Two copies of 8 and 19 are copied and transmitted to the trunk lines 11 and 12. At this time, in the TR area of each copied information frame, for the frame 20 transmitted to the relay line 11, 4 is stored as the exchange number and 11 is stored as the relay line number, and the frame 21 transmitted to the relay line 12 is stored. , 4 is stored as the exchange number and 12 is stored as the relay line number, and the S area 2 is set to have S designation. Furthermore, the time at that time (10:00
Minutes 00 seconds) is stored. The state is the same as in FIG.

In the relay station 6, the frame 21 received from the relay line 12 is stored in the S region as it is, and the TR region is stored by overwriting with 6 as the exchange number and 13 as the relay line number.
The T area is relayed as it is. Frame 2 at the called station 5
Check whether the difference between the current time at the receiving station and the time in the T area is equal to or more than a pre-specified network parameter before receiving 0 and 22 and executing the discard processing of the duplicated frame. If it is exceeded, the S designation of the incoming frames 20 and 22 is passed to the discarding process of the duplicate frame with S designation regardless of the original S designation. In this example, for both frames 20 and 22, after S is designated, the process moves to discarding duplicate frames,
Suppose 0 is valid. In the subsequent process, as in the normal process, a delivery confirmation frame for confirming the delivery of the frame is created based on the frame 20. Frame 20
Since there is S designation, the transmission confirmation frame is only transmitted to the fixed route 18 (11 as the relay line) without performing the copying operation. This situation is similar to FIG.

Example 2. Next, a case will be described in which a transient failure occurs in a fixed path due to a momentary interruption or the like, and none of the copied frames reaches the destination station and the retransmission request frame is sent from the destination station. FIG. 8 shows a sequence diagram when the S designation in the retransmission request frame is S designated (FIG. 8A) and when it is not designated (FIG. 8B). Figure 8
As shown in (b), it is possible to reduce the number of information frames to be retransmitted by specifying S for the retransmission request frames 29 and 30.

Example 3. In the first embodiment, the data transfer method in which the TR area and the S area are applied to the information frame and the retransmission request frame is shown, but it is applied to the in-network control frame for transmitting the closed management information and failure information in the network. An example is shown below. The applicable intra-network control frame is described with respect to the intra-network control frame having a command / response relationship. In-network control frames having a command / response relationship are generally important frames in many cases. Therefore, for command frames and response frames of in-network control frames, it is necessary to discard duplicate frames in the exchange. To do.

In the sequence shown in FIG. 9A, when the exchange 4 sends an intra-network control frame to the exchange 5, the intra-network control frame sent by the exchange 4 is copied and S is designated.
8 and 19 show that frames 35 and 36 are transmitted, respectively. The frame 36 is relayed by the exchange 6 and becomes a frame 37, which arrives at the exchange 5. Since both frames have S designation in the receiving station 5, the response frame 38 is transmitted only for the fixed route 18 to the command frame 35, and the response frame 39 is transmitted only for the fixed route 19 to the command frame 37.

In the sequence shown in FIG. 9B, when the exchange 4 sends an intra-network control frame to the exchange 5, the intra-network control frame to be sent is copied to the fixed routes 18 and 19 without S designation. It shows that the frames 35 and 36 are transmitted. The frame 36 is relayed by the exchange 6 and becomes a frame 37, which arrives at the exchange 5. Since the receiving station 5 does not specify S for both frames, it sends a response frame 38 to the fixed route 18 and a response frame 41 to the fixed route 19 for the command frame 35. On the other hand, for the command frame 37, the response frame 43 is transmitted to the fixed route 18 and the response frame 39 is transmitted to the fixed route 19. In this example, it can be seen that the number of response frames becomes half when S is specified, as compared with when S is not specified.

[0029]

As described above, according to the present invention, the number of frames to be copied in the network can be suppressed. In addition, the effect of preventing congestion from converging when congestion occurs can be expected.

[Brief description of drawings]

FIG. 1 is a diagram showing a frame format of the present invention.

FIG. 2 is a network configuration diagram for realizing a data transfer system according to an embodiment of the present invention.

FIG. 3 is a fixed path connection diagram for realizing the data transfer method according to the embodiment of the present invention.

FIG. 4 is a diagram illustrating a TR region according to an embodiment of the present invention.

FIG. 5 is a diagram showing a frame format and intra-network transfer when the data transfer system according to the embodiment of the present invention is applied to an information frame.

FIG. 6 is a diagram showing a frame format and intra-network transfer when the data transfer method according to the embodiment of the present invention is applied to a delivery confirmation frame.

FIG. 7 is a sequence comparison diagram for showing that a difference occurs in the number of delivery confirmation frames in the data transfer method according to the embodiment of the present invention depending on whether or not S is specified in the information frame.

FIG. 8 is a sequence comparison diagram for showing that a difference occurs in the number of information frames to be retransmitted according to the presence / absence of S designation in the retransmission request frame in the data transfer method according to the embodiment of the present invention.

FIG. 9 is a sequence comparison diagram for showing that a difference occurs in the number of intra-network control response frames in the data transfer method according to the embodiment of the present invention depending on whether or not S is specified in the intra-network control command frame.

[Explanation of symbols]

Area for storing one set of switching center number and relay line number in one frame format (TR area) Area indicating whether to use one set of switching center number and relay line number in frame format ( S area) 3 area for storing copy frame creation time in frame format (T area) 4 to 6 switching station 7 to 8 terminal 9 to 10 terminal line 11 to 13 relay line 14 notifying means 15 monitoring means 16 detecting means 17 copying means 18-19 fixed route

Claims (5)

[Claims] 1. A plurality of routes are set between two stations respectively accommodating terminals for data communication, and a plurality of data from the terminals on the transmitting station side are copied at the transmitting station to create information frames for the copies. , A region for storing a set of station number and relay line number in the information frame in the data transfer method in which the created information frame is transmitted for each route, and the receiving station discards duplicate information frames and controls the order. (TR area) and an area (S area) indicating whether or not to utilize the contents of the TR area are set, the TR area and the S area are set in the transmitting station, the TR area is updated in the relay station, and the receiving station is set. In the data transfer method, the number of delivery confirmation frames for information frames is limited based on the S area. 2. In the data transfer method, each station is:
Notifying means for notifying other stations of the traffic state of the own station, monitoring means for monitoring the traffic state of each route from the notified traffic state of each station, detecting means for detecting a congestion route from the traffic state, and route When congestion is detected, the information frame is prevented from being transmitted to the congested route, and a copy means for setting the S area of the information frame is provided to confirm delivery from the route without the congestion. The data transfer method according to claim 1, wherein a frame is expected. 3. The data transfer system according to claim 1, wherein the S area is fixedly set for a specific type of frame in the data transfer system. 4. In the above data transfer method, the transmitting station sets the S area of the information frame to be transmitted to all routes, and the receiving station receives all the information without discarding duplicate information frames. The data transfer system according to claim 1, wherein a delivery confirmation frame is returned to the frame. 5. A plurality of routes are set between two stations respectively accommodating terminals for data communication, and a plurality of data from the terminals on the transmitting station side are copied at the transmitting station to create information frames for the copies. , A region for storing a set of station number and relay line number in the information frame in the data transfer method in which the created information frame is transmitted for each route, and the receiving station discards duplicate information frames and controls the order. (TR area) and an area (T area) for storing the time of transmission,
At the originating station, the time at which the call originated was set in the T area, and at the called station, the elapsed time from the call to the incoming call became a value that was greater than or equal to the prespecified threshold value, based on the time set in the TR area. A data transfer method that suppresses the number of delivery confirmation frames by determining that congestion has occurred on the route by detecting.