JPH02209044A - Exchange - Google Patents

Abstract

PURPOSE:To revise a transmission path of communication information in real time by preparing plural different paths to various kinds of communication information in advance to a transfer table of an exchange. CONSTITUTION:Plural sets of information relating to outgoing lines corresponding to given number of each packet of communication inputted in advance and of given numbers of the outgoing lines are registered to a transfer table 133. A monitor circuit 135 monitors the traffic state of the outgoing line and a signal from other exchange and the monitor circuit 135 sends a path change signal to the transfer table 133 when it is discriminated that the traffic state of the outgoing line does not satisfy the transmission of the communication information or the change of the line is requested from other exchange. Thus, a transmission line of a part of communication is connected to other path prepared in advance to decrease the aborted packets or the increase in the delay time.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a switching device, and more specifically, for each packet to be rented, a number is determined in advance for each line to be used, and a number is assigned to each packet to be exchanged. Each switching device that performs relaying stores information on the outgoing line and the assigned number on the outgoing line corresponding to each assigned number, and the packets arrive at the destination line via a specific route while changing the assigned numbers at each switching device. The present invention relates to a switching device that allows the user to

In other words, the present invention relates to a switching device having a function of selecting a transmission route from a plurality of detour lines in real time based on the usage status of communication network equipment or failure information of communication equipment.

[Conventional technology]

For the purpose of multiplex transmission of multiple communication information on one line, a number is assigned to each packet for each line, and each switching device determines the number assigned to the outgoing line and the outgoing line according to the assigned number, and sends it out. There is a method of transmission. In this system, the switching device has the functions of reassigning the assigned numbers and selecting and connecting outgoing lines.

Such a conventional exchange device is shown in FIG. 3, in which:
Packets are input as communication information from the incoming line 121. The assigned number conversion circuit 131 derives the outgoing line registered in the transfer table 233 and the assigned number for the outgoing line from the assigned number of the packet. The transfer table 233 has the configuration shown in FIG. 4, that is, for an incoming line assigned number inputted from the control line 141, the corresponding (outgoing line+assigned number) is outputted on the control line 142. The assigned number conversion circuit 131 assigns a new number assigned on the outgoing line to the packet. Next, the line selection circuit 132 connects each packet to the outgoing line similarly specified in the transfer table 233 and sends it out.

FIG. 5 shows a communication network configured with conventional switching devices. In the figure, 501 to 506 are switching devices, and 511 to 518 are switching devices.
are lines connecting the switching devices, and 521 to 523 are transfer table information of the switching devices 502 to 504, respectively.

In the packet shown by a box in the figure, the assigned number #i is converted into the assigned number #j in the switching device 502, and the line 513 is selected. Similarly, the switching device 503 converts the assigned number "#" into an assigned number #k, and sends it to the line 514. The switching device 504 also performs conversion from assigned number #k to #2 and selection of line 515.

Here, if the line 514 handles a large number of packets and the usage rate of the line increases, there is a possibility that the buffer corresponding to the line in the switching device 503 will overflow and packets will be discarded.

[Problem to be solved by the invention]

As explained above, the assigned number conversion information is set in advance in the transfer table, and the assigned number conversion circuit assigns the assigned number to the outgoing line.9 The line selection circuit connects and sends the assigned number to the outgoing line, thereby allowing multiple exchanges. Communication information can be transferred via the device. In a communication network that connects multiple switching devices,
It is conceivable that packets may concentrate on a single line on a communication network in excess of the capacity of the line. In this case, it is necessary to store packets in the switching device until the desired line capacity becomes available.

However, the number of packets that can be stored in the switching device is
Limited by the amount of memory available on the exchange device. Furthermore, since there is a limit to the delay time of communication information at the terminal, there is a possible drawback that packets that have been accumulated for more than a certain period of time must be discarded.

An object of the present invention is to provide a switching device that can improve these drawbacks.

[Means to solve the problem]

In order to achieve the above object, in the first feature of the present application, in a switching device that accommodates an incoming line and an outgoing line and has an assigned number conversion circuit, a transfer table, and a line selection circuit, packets input from the incoming line are Multiple sets of outgoing line selection information and replacement assigned number information corresponding to the assigned number included in the header information are stored in advance in the transfer table for each assigned number included in the header information, and each A monitoring circuit is provided which monitors the usage rate of the outgoing line and signals from other switching devices and notifies the assigned number conversion circuit of communications that are determined to require line change.

Further, in the second invention of the present application, in the switching device, a buffer circuit for line change is provided between the assigned number conversion circuit and the line selection circuit.

(Function) In the first invention of the present application, the assigned number conversion circuit refers to the forwarding table based on the assigned number included in the header information of the packet input from the incoming line, and changes the assigned number of the packet and outputs the packet. When performing line selection, for the communication packet notified from the monitoring circuit, among the multiple sets stored in the transfer table, the outgoing line selection information that should originally be used and the assigned number information for replacement are Instead, the assigned numbers are replaced and the outgoing line is selected using those of another set, and the line selection circuit connects to the outgoing line and sends out.

In other words, in the invention of Part 1, by preparing in advance a plurality of different routes for each piece of communication information in the transfer table of the switching device between terminals or switching devices, packets are transferred to a specific switching device or outgoing line. When packets are concentrated and there is a risk of packets being discarded, for some of these communications, the transmission route for the packets of that communication is connected to another route prepared in advance to reduce bat discards and increases in delay time. ing. Additionally, in the event of a failure in another switching device or line, it is possible to quickly switch communications that are at risk of being affected to other routes.

In addition, in the invention of the present application 2, when changing the transfer route of a specific communication with the switching device as the invention of the present application 1,
In order to prevent a reversal of the packet arrival order that would occur due to the use of two transfer routes with different delay times, a buffer circuit provides a necessary and sufficient delay time to the packets of the communication for which the line is to be changed.

〔Example〕

FIG. 1 is a block diagram showing a switching device as an embodiment of the present invention. In the figure, a switching device 111 accommodates an incoming line 121 and an outgoing line 122, an assigned number conversion circuit 1311, a line selection circuit 132, a monitoring circuit 135. It consists of a transfer table 1331 consisting of memory and a line change buffer circuit 134, and connection lines 123, 124, 125 for communication information and a control connection circuit 1411 connect each block.
42, 143, 144, and other switching equipment and lines 151
Connected with

As shown in FIGS. 2(a) and 2(b), the transfer table 133 includes a plurality of pieces of information on outgoing lines and numbers assigned on the outgoing lines corresponding to the numbers assigned to each packet of communication input in advance. (In this example, the first and second candidates) are registered.

For each packet input from the incoming line 121, a new assigned number and outgoing line (first candidate) are determined from the assigned number information written in the header information of that packet, as shown in FIG. 2(a), and output. be done.

The assigned number conversion circuit 131 assigns a new assigned number to the packet based on this information, and the line selection circuit 132 connects the packet to the designated outgoing line.

Send.

The monitoring circuit 135 monitors the traffic status of the outgoing line and signals from other switching devices. When the monitoring circuit 135 determines that the traffic status of the outgoing line cannot satisfy the transmission of communication information, or when a line change is requested from another switching device, the monitoring circuit 135 uses transfer table 1.
A route change signal is sent to 33.

According to the signal from the monitoring circuit 135, the assigned number conversion circuit 131 determines a second candidate outgoing line and outputs the input packet with a specific assigned number as shown in FIG. 2(b). From now on, the specified line and assigned number will be used for transmission. Connect the corresponding packet to the newly changed circuit in the line selection circuit 132,
Send.

Through this operation, the monitoring circuit monitors the traffic status of each line, the axis of other exchanges, failures, etc., and if a packet is sent to a specific exchange or outgoing line and there is a risk that the packet will be discarded, the - By connecting the communication transmission route to another route prepared in advance, packet discards and increases in delay time can be reduced. Furthermore, in the event of a failure in another switching device or line, communications that are at risk of being affected by the failure notification can be quickly switched to another route.

Next, when communication is switched between multiple outgoing lines in this way, there is a risk that the order of arrival at the destination will change from the order of arrival at the incoming line due to the difference in the amount of delay between the outgoing lines. Therefore, this problem is solved by providing a buffer circuit 134 for changing the outgoing line and providing a necessary and sufficient delay at the time of changing the outgoing line.

FIG. 6 shows a communication network using the switching device of the present invention. 601-606 are exchange devices, 621-624
are transfer tables of exchange devices 602, 603, 604, and 606, respectively.

In this communication network, switching equipment 602 has multiple outgoing line candidates for assigned number #1, and switching equipment 603, 6
06 respectively have assigned number conversion information, and exchange device 6
04, the assigned number #J' input from the line 518 and the assigned number #J' inputted from the line 514 are assigned the same outgoing line and the assigned number for the same outgoing line.

In normal operation, switch 602 sends packets onto one line, eg, line 513. Here, when the line 514 handles a large number of packets and the usage rate of the line increases, the switching device f603 requests the switching device 602 to change the line. The switching device 602 distributes communication information of packets forming the communication to another outgoing line, for example, the line 517, for a communication whose outgoing line can be changed. At this time, route 51
3° 514 and the routes 517 and 518, the time order of the communication information may be reversed.

This is controlled by the line change buffer 134.

〔Effect of the invention〕

According to the present invention, the transmission route of communication information can be changed in real time. This makes it possible to improve line utilization.

In addition, even if a particular switching device or line becomes unavailable due to a failure in communication network equipment, the transfer of communication information can be continued using multiple lines prepared in advance.
A highly reliable communication network can be constructed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a switching device as an embodiment of the present invention, and FIGS. 2(a) and 2(b) show an outgoing line in a transfer table and a method of determining numbers assigned to the outgoing line in the case according to the present invention. 3 is a block diagram showing a conventional switching device, FIG. 4 is an explanatory diagram of an outgoing line and a method of determining the assigned number in the outgoing line using a transfer table of the conventional switching device, and FIG. 5 is a conventional communication FIG. 6 is an explanatory diagram showing a method of transmitting communication information in a network. FIG. 6 is an explanatory diagram showing a transmitting method using the switching device of the present invention. Explanation of symbols 111...Switching device, 131...Assigned number conversion circuit, 132...Line selection circuit, 133...Transfer table, 135...Monitoring circuit, 601-606...Switching device . Agent Patent Attorney Akio Namiki

Claims (1)

[Scope of Claims] 1) In a switching device that accommodates an incoming line and an outgoing line and has an assigned number conversion circuit, a transfer table, and a line selection circuit, an assignment included in the header information of a packet input from the incoming line. Multiple sets of outgoing line selection information and assigned number information for replacement corresponding to the number are stored in advance in the transfer table for each assigned number included in the header information, and the utilization rate of each outgoing line and other information are stored in advance in the transfer table. a monitoring circuit that monitors signals from the switching equipment and notifies the assigned number conversion circuit of communications that are determined to require a line change; When reassigning a packet number and selecting an outgoing line by referring to the forwarding table from the assigned number included in the header information, the communication packets notified from the monitoring circuit are stored in the forwarding table. Among the multiple sets, the outgoing line selection information and the assigned number information for replacement that should be used are not used, but those of other sets are used to change the assigned number and select the outgoing line, and the line selection circuit A switching device characterized in that it connects to an outgoing line and transmits data. 2) The switching device according to claim 1, wherein a buffer circuit for line change is provided between the assigned number conversion circuit and the line selection circuit, and a packet is sent via the buffer circuit when changing the line. exchange device.