JP3606315B2 - Switching method when accommodating high-speed interfaces - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ATM switch or a packet switch in a network system that performs communication by an ATM (Asynchronous Transfer Mode) method, and in particular, a plurality of low-speed lines as one high-speed line in order to accommodate lines having different line speeds. It is related with the switch system to accommodate.
[0002]
[Prior art]
STM (Synchronous Transfer Mode) is suitable for transferring information that occurs continuously, such as audio and video, but ATM (Asynchronous Transfer Mode :) is used to transfer bursty information such as computer data. Asynchronous transfer mode) is suitable, and ATM is also suitable for efficiently transferring information when lines from low speed to high speed are mixed.
In ATM, all information is divided into fixed-length blocks called cells. A cell is a total of 53 bytes including 48 bytes of information and 5 bytes of header including the transfer destination and label, and is transferred by time division multiplexing in units of cells. Is done.
A cell to be transferred enters an input terminal (input port) in the ATM switch, is connected to the switch while selecting a route according to the header address, and is sent to an output terminal (output port) corresponding to the line number of the header.
[0003]
When information is transmitted by connecting a line speed higher than the switching speed of the ATM switch, or when lines with different line speeds are connected, a method of assigning and using a plurality of input / output ports as one line is used. . The operation of the ATM switch when accommodating a high-speed line conventionally used will be described with reference to FIG. As a conventional method, a high-speed interface is accommodated using a scheduler that handles each input / output port individually for each port, and the cell from which input port the cell is output before sending a transmission request to the scheduler via the input interface. There is a method for determining in advance. For example, the input interface needs to determine from which input port to which output port a cell is transmitted before sending a transmission request to the scheduler.
[0004]
In FIG. 9A, the switch section 14 has input ports IN0 to IN7 and OUT0 to IN7, IN0 is the input interface 111, IN1 is the input interface 112, IN2 to 5 are the input interface 113, and IN6 to 7 are An input interface 114 is connected, OUT0 to 3 are connected to an output interface 121, OUT4 is connected to an output interface 122, OUT5 is connected to an output interface 123, and OUT6 to 7 are connected to an output interface 124. At some point, the input interface 111 has a cell 91 addressed to the output interface 121, generates a connection allocation request from the input port 0 to the output port 0, and the input interface 113 also has cells 92, 93, 94 addressed to the output interface 121. Yes, cell 92 generates a connection allocation request for input port 3 → output port 0, cell 93 generates a connection allocation request for input port 4 → output port 1, and cell 92 generates a connection allocation request for input port 5 → output port 2. To do.
[0005]
The connection allocation request at this time is as shown in FIG. When connection allocation is performed in response to this connection allocation request, since the connection requests to the output port 0 are duplicated, the allocation result as shown in FIG. 9C is obtained, and the connection allocation request from the input port 3 to the output port 0 is obtained. No connection assignment is made for. There is also an input port 3 → output port 3 as a transfer path from the input interface 113 to the output interface 121. However, no assignment is made in this path, which causes waste and deteriorates transfer efficiency. Such waste occurs because the input interface side determines which output port to use when transferring to the output interface 121.
[0006]
Also, in order to guarantee the cell order in the switch, it is necessary to assign a sequence number at the input interface, and after transferring at the switch, it is necessary to sort the cells by looking at the sequence number at the output interface. As a result, the guarantee method becomes complicated and the transfer is delayed.
[0007]
[Problems to be solved by the invention]
In order to solve the above-mentioned problems of the prior art, the present invention provides an ATM switch that allocates a plurality of input / output ports and accommodates a high-speed line, performs cell order guarantee with simple control, and connects efficiently. It is an object of the present invention to provide an ATM switching method capable of performing assignment.
[Means for Solving the Problems]
[0008]
The switching system of the present invention for solving the above problems is a switching system that forms an interface for transferring data faster than the switch port speed by accommodating a plurality of switch ports.BecauseThe input interface has a queue for temporarily storing cells for each destination information, and sends a transmission request signal to the scheduler unit. The scheduler unit performs connection assignment and sends a transmission permission signal to the input interface. The switch unit is switched by transmitting connection information to the switch unit, and the input interface transmits the cells stored in the queue to the switch unit based on the transmission permission signal, and according to the switch unit switching. The data is sent to the output interfaceOne output port number of an output interface accommodating a plurality of output ports is defined as a representative port number, and the destination information is used as a representative port number.
[0009]
Since cells can be temporarily stored in the queue of the input interface, and the scheduler unit can manage the cell sending order and destination, when multiple ports are used together as one high-speed logical port Switch connection allocation can be performed efficiently.
In addition, when a logical port is formed by accommodating a plurality of ports, the destination value is used as the representative value of the accommodated port, and it is sent to which of the ports accommodated in the logical port. Since the scheduler unit can manage, it is possible to reduce a transmission delay due to overlapping output port designations, and to realize efficient switch connection allocation.
[0010]
Moreover, the switching system for solving the said subject isA switching method that forms an interface that transfers data faster than the switch port speed by accommodating multiple switch ports. The input interface has a queue that temporarily stores cells for each destination information. And sending a transmission request signal to the scheduler unit, the scheduler unit allocating connections and sending a transmission permission signal to the input interface, transmitting connection information to the switch unit and switching the switch unit, The interface sends out the cells stored in the queue to the switch unit based on the sending permission signal, and the data is sent to the output interface according to the switching of the switch unit,The input interface includes a line accommodation unit, a destination determination unit, a VOQ management unit, and a scheduler INF. The line accommodation unit converts packet data into a fixed-length cell, and the destination determination unit is configured for each cell. The VOQ management unit stores a cell in a queue for each destination information, transmits a transmission request to the scheduler unit via the scheduler INF, and sends the scheduler INF to the cell. Receiving a transmission permission from the scheduler unit via the cell, and sending a cell to the input port based on the transmission permission,One output port number of an output interface accommodating a plurality of output ports is defined as a representative port number, and the destination information is used as a representative port number.It is characterized by that.
[0011]
It is possible to store cells for each output port by assigning the output port number, which is the cell transmission destination, to the cell as the destination information by the destination determination unit and storing the cell in the queue of the VOQ management unit for each destination information. Thus, when cells are transmitted according to the transmission permission, a plurality of cells can be transmitted simultaneously from one queue, and efficient switch connection assignment can be realized.
[0013]
When a logical port is formed by accommodating a plurality of ports, the scheduler unit determines which of the ports accommodated in the logical port is to be sent by using the representative value of the accommodated port as destination information. Therefore, it is possible to reduce a transmission delay due to duplication of output port designation, and to realize efficient switch connection allocation.
[0014]
Further, the switching method for solving the above problem is that the scheduler unit includes a request management unit, a request conversion unit, a switch connection determination unit, and a connection allocation conversion unit, and the request management unit includes the queue A request counter that is a matrix that stores the number of cells stored in correspondence with the input port and destination information, generates a connection allocation request based on the information of the request counter, and transmits it to the request conversion unit, The request conversion unit converts the connection allocation request into a second connection allocation request and transmits it to the switch connection determination unit, and the switch connection determination unit displays a connection allocation result based on the second connection allocation request. Generating and notifying the switch unit to switch the switch unit, transmitting the connection allocation result to the connection allocation conversion unit, and A conversion unit that converts the connection allocation result into a second connection allocation result and transmits the result to the input interface as the transmission permission signal, and transmits the second connection allocation result to the request management unit; The management unit updates the contents of the request counter based on the second connection allocation result.
[0015]
The scheduler unit manages the cells stored in the queue by updating the request counter, and by allocating the connection, it accurately grasps the cells stored in the VOQ management unit of the input port and switches efficiently. Connection allocation can be performed.
[0016]
In the switching method for solving the problem, the scheduler unit includes a switch connection determination unit, the input interface includes a request management unit, a request conversion unit, and a connection allocation conversion unit, and the request management unit A request counter that is a matrix that stores the number of cells stored in the queue in association with input ports and destination information, and generates a connection allocation request based on the information of the request counter and converts the request And the request conversion unit converts the connection allocation request into a second connection allocation request and transmits the request to the switch connection determination unit. The switch connection determination unit determines whether the second connection allocation request is based on the second connection allocation request. A connection allocation result is generated and notified to the switch unit to switch the switch unit, and the connection allocation result is converted to the connection allocation conversion. And the connection allocation conversion unit converts the connection allocation result into a second connection allocation result and transmits the result to the input interface as the transmission permission signal, and the second connection allocation result is transmitted to the request management unit. The request management unit updates the content of the request counter based on the second connection allocation result.
[0017]
The input interface unit manages the cells stored in the queue by updating the request counter, and by allocating the connection, it accurately grasps the cells stored in the VOQ management unit of the input port and is efficient. Switch connection assignment can be performed.
[0018]
The switching method for solving the problem is a matrix indicating the presence / absence of a cell in which the connection assignment request uses the representative output port as destination information, and the conversion to the second connection assignment request is performed by the representative output port. The presence / absence of a cell having the representative output port as destination information is copied to all the output ports accommodated in the output interface expressed by
[0019]
Since the connection allocation request is a matrix indicating the presence / absence of a cell, and the second connection allocation request is a copy of the presence / absence of a cell having the representative output port as destination information, the scheduler unit stores it in a queue It is possible to treat the cell being transmitted as being sent to any one of the output logical ports. As a result, when the scheduler unit performs efficient switch connection allocation, information for determining which input port is used for transmission is obtained.
[0020]
The switching method for solving the problem is characterized in that the conversion from the connection assignment result to the second connection assignment result is aggregation of the connection assignment result into a representative port number.
[0021]
By consolidating connection assignments to representative ports, cells stored in a queue for each destination information can be transmitted with the representative port number as the destination, and efficient switch connection assignment can be performed.
[0022]
Further, the switching method for solving the above problem is that when cells having the same representative output port as destination information are sent simultaneously, the cells are sent to the input ports according to a predetermined order, and the cells are sent according to the predetermined order at the output interface. It outputs to an output line.
[0023]
When sending cells stored in the queue for each destination information according to sending permission, if there are multiple sendings addressed to the same representative port, cells will be delivered according to a predetermined order, It is possible to easily guarantee the order of cells stored in the input interface and the order of cells transmitted from the output interface.
[0024]
In the switching method for solving the problem, the predetermined order is to send cells to the younger input ports in order from the head of the queue, and to output in order from the cells sent from the younger input ports at the output interface. It is output to a line.
[0025]
When sending cells stored in the queue for each destination information according to the sending permission, if there are multiple sends addressed to the same representative port, the cells are sent in order from the youngest number of the input port accommodated, By sending cells in the order of the input port numbers in the output interface, it is possible to send out from the output interface in the order in which they are stored in the queue. Therefore, the order of the cells stored in the input interface and the cell sent from the output interface Order guarantee can be easily performed.
[0026]
Embodiment
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a structure of a switching device according to the present invention. FIG. 1 shows a configuration example in the case where there are eight input / output ports. However, the number of input ports and the number of output ports can be arbitrary natural numbers, and the number of input ports and the number of output ports are not necessarily the same. In addition, although switching of fixed-length cells is shown as an example, it can also be applied as a switch that handles variable-length data.
[0027]
The switching device includes input interfaces 111 to 114 that accommodate various lines, output interfaces 121 to 124, a scheduler unit 13 that determines connection of the switch unit 14, and a cross between the input ports IN0 to IN8 and the output ports OUT0 to OUT8. And a switch unit 14 having a function of performing connection. In the following description, when expressed as a high-speed input interface and a high-speed output interface, it represents an interface accommodated in a switch using a plurality of switch ports. When expressed as a port, it represents a physical switch port.
[0028]
The input interfaces 111 and 112 can accommodate a line having a speed lower than the switch port speed, and are connected to the switch unit 14 using one switch port. The input interfaces 113 and 114 can accommodate lines having a speed that is A times the switch port speed (A: a natural number between 1 and N, N: a natural number less than the total number of switch ports). A port is used to connect to the switch unit 14. The value of A takes a value corresponding to the line speed accommodated by each input interface, and can take a different value for each input interface.
[0029]
In FIG. 1, the high-speed input interface is accommodated using a plurality of continuous input ports. However, the input port used when accommodating the high-speed input interface is not necessarily a continuous input port. The input interfaces 111 to 114 accommodate various lines (POS, Ethernet, ATM, etc.), and when the received data is variable length data such as a packet, it is divided into fixed length cells (hereinafter referred to as cells). The cell is managed for each destination, the transmission request 151 to the switch is transmitted to the scheduler unit 13 based on this management information, and the cell is transmitted to the switch unit 14 based on the transmission permission 152 received from the scheduler unit 13. Do.
[0030]
The output interfaces 122 and 123 can accommodate a line having a speed lower than the switch port speed, and are connected to the switch unit 14 using one switch port. The output interfaces 121 and 124 can accommodate a line having a speed A times the switch port speed (A: a natural number between 1 and N, N: a natural number less than the total number of switch ports). A port is used to connect to the switch unit 14. The value of A takes a value corresponding to the line speed accommodated by each output interface, and can take a different value for each output interface.
[0031]
Although the high-speed output interface is accommodated using a plurality of continuous output ports in FIG. 1, the fishing port used when accommodating the high-speed output interface is not necessarily a continuous output port. The output interfaces 121 to 124 receive cells from the switch unit 14 and send data to the line side.
[0032]
The switch unit 14 is a block that receives the connection information 17 between the input port and the output port from the scheduler unit 13, performs switching of the input main signal data 161, and outputs the main signal data 162 to a predetermined output port. . In FIG. 1, an 8 input × 8 output switch is used, but the number of input ports and the number of output ports are arbitrary, and the number of input ports and the number of output ports may be different.
[0033]
The scheduler unit 13 includes a request management unit 131, a request conversion unit 132, a switch connection determination unit 133, and a connection allocation conversion unit 134.
The request management unit 131 receives the transmission requests 151 from all the input interfaces (REQ0 to 7), manages the number of transmission requests 151 for which connection allocation is not performed, generates a connection allocation request, and sends the request to the request conversion unit 132. Transmit (R31). The request conversion unit 132 converts the received connection allocation request based on the accommodation status of the input interface and the output interface, and notifies the conversion result to the switch connection determination unit 133 (R32).
The switch connection determination unit 133 determines the connection between the input port and the output port of the switch unit 14 based on the received connection allocation request, transmits the connection information 17 to the switch unit 14, and connects the connection allocation conversion unit 134 and the switch unit. The connection allocation result is transmitted to 14 (G33).
The connection allocation result conversion unit 134 converts the received connection allocation result based on the accommodation status of the input interface and the output interface, notifies the input interface units 111 to 114 of the transmission permission 152, and simultaneously displays the converted connection allocation result. The request management unit 131 is notified (G34).
[0034]
Here, an example is shown in which the scheduler 13 includes all of the request manager 131, the request converter 132, the switch connection determiner 133, and the connection allocation converter 134. However, even if the request management unit 131, the request conversion unit 132, and the connection allocation conversion unit 134 are arranged in the input interface and only the switch connection determination unit 133 is included in the scheduler unit, other forms of deployment are possible. Even so, the connection relationship and operation of each part may be the same as in the above-described example.
[0035]
The detailed configuration of the input interface is shown in FIG. The input interface includes a line accommodating unit 21, a destination determining unit 22, a VOQ management unit 23, and a scheduler INF 24.
The line accommodating unit 21 accommodates the line 211, divides the received data into fixed-length cells, and transmits the cells to the destination determining unit 22 (212).
The destination determination unit 22 determines to which output interface the received cell is output, and transmits the destination and main signal data (cell) based on the determination result to the VOQ management unit 23 (213).
The VOQ management unit 23 manages a cell for each destination, transmits a transmission request 221 to the switch to the scheduler INF 24 based on this management information, and based on the transmission permission received from the scheduler INF 24, the main signal data (cell ) Is output to the switch unit (214).
The scheduler INF 24 performs conversion work on the transmission request 221 received from the VOQ management unit 23 and transmits the converted transmission request 222 to the scheduler unit 13. The transmission permission 223 received from the scheduler 13 is transmitted to the VOQ management unit 23 (224).
[0036]
Next, the operation of the input interface according to the embodiment of the present invention will be described in detail with reference to FIG. The line accommodating unit 21 receives data from the line 211, performs processing specific to the accommodated line, and if the received data is variable-length data such as a packet, divides the cell into fixed-length cells, The cell is transmitted to 22. The destination determination unit 22 determines which output interface the received cell is transferred to, and then transmits the cell and destination information to the VOQ management unit 23 (213). In the following description, the destination output interface is a switch This is expressed using the output port number.
[0037]
A specific example will be described with reference to FIG. When forwarding to the output interface 122 connected by one switch port, the destination is the output port OUT4. When it is desired to output to the output interface 121 connected by four switch ports, the main signal data can reach the output interface 121 via any of the four output ports OUT0 to OUT3. The output ports OUT0 to OUT3 can be regarded as one logical port. Therefore, one of the four output ports OUT0 to OUT3 is selected as a “representative port”, and the destination is defined using the representative port.
[0038]
In the example of FIG. 3, the output ports OUT0 to OUT3 are represented by the representative port OUT0. Therefore, the destination of the cell addressed to the output interface 121 is OUT0. Similarly, if the representative port of the output ports OUT6 and OUT7 is OUT6, the destination of the cell addressed to the output interface 224 is OUT6. Here, OUT0 having the smallest port number is selected as the representative port of the output ports OUT0 to OUT3. However, any representative port that is connected to the same output interface can be selected. Absent. That is, there is no problem even if OUT2 is selected instead of OUT0 as the representative port of OUT0 to OUT3. In the case of an output interface connected by a single switch port, the representative port is considered to be the same as the output port.
[0039]
2, the VOQ management unit 23 receives the cell and destination information 213 from the destination determination unit 22, stores the cell in a queue for each destination, that is, for each output interface (41 to 44 in FIG. 4), and stores the cell in the scheduler INF14. The transmission request 221 is sent out. Also, the cell transmission permission 224 is received from the scheduler INF14, and the cell addressed to the output port permitted to be transmitted is transmitted to the switch unit (214).
[0040]
The operation in the case of the input interface 111 in which the VOQ management unit transmits a cell when receiving an output permission and has only one switch port will be described below with reference to FIG.
When the output permission from the switch port IN0 to the output port OUT0 (hereinafter referred to as IN0 → OUT0) is received, the first cell 401 is read from the queue 41 addressed to OUT0 and output to the input port IN0. The cell output to the input port IN0 passes through one of the four output ports OUT0 to OUT3 represented by the representative output port OUT0 and is transferred to the output interface 121 via the switch unit. As an example, it passes through OUT1 in FIG.
[0041]
Next, the operation when the input interface 113 connected to the four switch ports receives the output permission when the cell is transmitted when the output permission is received will be described with reference to FIG.
In the case of the input interface 113, four switch ports are connected.
A plurality of transmission permits are received simultaneously. The maximum number of transmission permits received simultaneously is the number of input ports connected to the input interface. In the case of the input interface 113, there is a possibility that a maximum of 4 transmission permits may be received simultaneously.
[0042]
For example, if four transmission permissions of IN2 → OUT4, IN3 → OUT0, IN4 → OUT0, IN5 → OUT6 are received, the first cell 521 of the queue 52 addressed to the output port OUT4 is output to the switch port IN2, The data is transferred to the output interface 122 via the switch unit. Similarly, the head cell 541 of the queue 54 addressed to the output port OUT6 is output to the switch port IN5 and transferred to the output interface 124 via the switch unit.
[0043]
Since there are a plurality of transmission permits addressed to the output port OUT0, such as IN3 → OUT0, IN4 → OUT0, the number of cells (511, in the example of FIG. 512 two cells) are read out and output to the input port where transmission permission is obtained. At this time, input ports are output so that cells that arrive in the queue first (the cell at the head of the queue) are output to the youngest input port in order, and the cells that arrive later are output to the input port with the larger port number. Make assignments.
[0044]
In the output interface, the cells received from the younger input ports are output to the line side in order. As a result, the cell order can be guaranteed even if a plurality of cells addressed to the same output interface are simultaneously transmitted. In the example of FIG. 5, the cell 501 at the head of the queue 51 addressed to the output port OUT0 is output to the young input port IN3, and the cell 502 that was second in the queue 51 is output to the input port IN4. . The output interface 121 receives the cell 511 sent from the input port IN3 and the cell 512 sent from the input port IN4 at the same time, but when outputting to the output line 55, the cell sent from the younger input port. Multiplex in order. In the example of FIG. 5, the cell 511 sent from the input port IN3 is first output to the output line 55, and then the cell 512 sent from the input port IN4 is output to the output line 55. In this way, in the output interface, it is possible to guarantee the cell order by outputting the cells sent from the younger input port in order to the output line.
[0045]
Here, an example in which the first cell in the queue of the input interface is output in order from the youngest input port when a plurality of transmission permissions are obtained is described, but a plurality of cells for which transmission permission is obtained are described. A rule for determining how to output to a plurality of input ports is defined. If both the input interface and the output interface transfer cells according to the same rule, the order can be guaranteed. Examples of rules include the method of outputting to the youngest input port in order from the cell at the head of the queue as described above, and the method of outputting to the input port having the highest number in order from the cell at the head of the queue. It is done.
[0046]
The scheduler INF 24 shown in FIG. 2 receives a transmission request 221 from the VOQ management unit 23 and transmits a transmission request 222 to the scheduler 13, and receives a transmission permission 223 from the scheduler 13 and sends a transmission permission 224 to the VOQ management unit 23. Has a function to notify.
[0047]
First, transmission of the scheduler INF transmission request 222 will be described. In the case of the input interface 111 or 112 having only one switch port, the scheduler INF 24 does not perform any special processing on the transmission request 221 received from the VOQ management unit 23, and the received transmission request 221 is directly used as the transmission request 223. Transmit to the scheduler 13. In the case of the high-speed input interfaces 113 and 114, since they are connected to a plurality of input ports, the transmission request 221 received from the VOQ management unit 23 is distributed to the plurality of connected input ports, and the transmission request 222 for each input port. Is transmitted to the scheduler unit 13.
[0048]
An example in the case of the input interface 113 is shown in FIG. The scheduler INF 24 receives the transmission request 221. The transmission request 221 includes the number of transmission requests for each output port. In FIG. 6, the output ports whose transmission request numbers are hatched are output ports that are not representative ports, and transmission requests are output only to the representative ports, so no transmission requests are generated for output ports that are not representative ports. . Since the high-speed input interface is connected to the four input ports IN <b> 2 to IN <b> 5, the received transmission request 221 is distributed to the four input ports and output to the scheduler unit 13. Arbitrary algorithms can be used for the distribution of the transmission requests to the input ports, but it is desirable to distribute the transmission requests as evenly as possible.
The transmission permission 223 received by the scheduler INF is directly transmitted to the VOQ management unit 23 as the transmission permission 224 without being converted.
[0049]
Next, the operation of the scheduler unit 13 will be described. The request management unit 131 has a request counter that manages the number of transmission requests for which connection allocation has not been completed. The request counter has a matrix configuration shown in FIG. 7A, and the number of transmission requests waiting for connection allocation is managed in units of input ports and output ports.
[0050]
For example, there are four transmission requests from the input port 5 to the output port 6. When receiving the transmission request 151 from the input interfaces 111 to 114, the request management unit 131 adds the content of the transmission request 151 to the request counter. Also, the connection assignment result G34 is received from the switch connection determination unit 133, and the request counter is subtracted. Based on the status of the request counter, the request management unit 131 generates a connection allocation request R31 and transmits it to the request conversion unit 132. The method of generating the connection allocation request R31 has the configuration shown in FIG. 7B, where 1 is set at a location where a connection request exists, and 0 is set at a location where no connection request exists. Represents.
[0051]
The request conversion unit 132 converts the connection allocation request R31 received from the request management unit 131 according to the accommodation status of the output interface, and transmits the converted connection allocation information R32 to the switch connection determination unit 133. For example, it is assumed that the connection allocation request R31 received from the request management unit 131 is as shown in FIG. According to this connection allocation request R31, it is understood that there is a connection allocation request from input port 0 to output port 0. As described above, the output port to which the output is to be output is represented by the representative port. Therefore, the connection assignment request to the representative output port 0 is an output request to the output interface 121.
[0052]
Since the output interface 121 is connected to the output ports 0 to 3, when there is a connection assignment request from the input port 0 to the representative output port 0, IN0 → OUT0, IN0 → OUT1, IN0 → OUT2, and IN0 → OUT3. Of these, connection allocation may be performed for any one of them. Therefore, the connection allocation request addressed to output port 0 is also copied to output ports 1 to 3 belonging to the same output interface. One connection allocation request is copied to make a total of four connection allocation requests. Since these four connection allocation requests all belong to the same input port, connection allocation is actually performed. It is guaranteed that there is at most one connection allocation request.
[0053]
Similarly, the connection assignment request of IN0 → OUT6 is also copied to IN0 → OUT7. A similar conversion operation is performed for all input ports. The connection assignment request after conversion is as shown in FIG. A square surrounded by a thick line in FIG. 7C represents a range in which the connection allocation request for the representative output port is copied.
[0054]
The switch connection determination unit 133 performs connection allocation between the input port and the output port of the switch based on the received connection allocation information R32, and any allocation algorithm can be used for this connection allocation. Thereafter, the connection allocation result G33, which is the result of the connection allocation, is notified to the connection allocation conversion unit 134, and at the same time, the connection allocation result is notified to the switch unit 14. An example of the connection allocation result is shown in FIGS.
[0055]
The connection allocation conversion unit 134 converts the connection allocation result G33 into information related to the representative output port, and transmits a transmission permission 152 to the input interface (GNT0 to GNT7). At the same time, the converted connection allocation result is transmitted to the request management unit 131 (G34).
[0056]
A method of converting the connection assignment result will be described with reference to FIG. It is assumed that the connection allocation information R32 converted by the request conversion unit 132 has the contents shown in FIG. 8A and the connection allocation result G33 received from the switch connection determination unit 133 is that shown in FIG. 8B. In FIG. 8B, the part where 1 is written is the combination of the input port and the output port to which connection assignment is performed. In the connection allocation result G33, the output port is not the representative port but the actual switch port number. On the other hand, in the input interfaces 111 to 114 and the request management unit 131, output ports are managed using representative ports. Therefore, it is necessary to convert the connection allocation result G33 into a connection allocation result expressed using the representative port. Specifically, the connection assignment results of the output ports 0 to 3 belonging to the same output interface 121 are collected in the representative port 0.
[0057]
That is, if connection assignment is made to any one of input port 0 → output port 0, input port 0 → output port 1, input port 0 → output port 2 and input port 0 → output port 3, input port 0 → Assume that connection assignment is made to the representative output port 0 (that is, 1 is set at the locations of the input port 0 and the output port 0). 0 is set for all output ports that are not representative ports. Similar processing is performed for all representative ports and all input ports. As a result, the converted connection allocation information is as shown in FIG.
[0058]
A transmission permission 152 is transmitted to each input interface based on the converted connection allocation information. For example, transmission permission to the output port 0 is transmitted to the input port 0, and transmission permission to the output port 6 is transmitted to the input port 4. Also, the converted connection allocation information is notified to the request management unit 131, and the request management unit 131 performs a subtraction process for the request counter.
[0059]
The switch unit 14 performs switching of the main signal data 161 input from the input port based on the connection allocation result 17 received from the scheduler unit 13, and outputs the main signal data 162 from the output port to the output interfaces 121 to 124.
[0060]
In FIG. 1, the request management unit 131, the request conversion unit 132, and the connection allocation conversion unit 134 are provided in the scheduler unit 13, but the functions may be divided into input interface units and distributed on the input interface. Is possible.
[0061]
FIG. 10 shows a schematic diagram of the switching device of the present invention. In a switch in which the communication speed of each switch port is 2.4 Gbit / sec, a communication speed of 10 Gbit / sec is provided by forming an interface accommodating four switch ports by using the above-described invention of the present application. It can be an interface.
[0062]
【The invention's effect】
By using the present invention, a high-speed interface can be accommodated using a plurality of switch ports, and even when a high-speed interface is accommodated, switch connection assignment can be performed efficiently. This effect can be obtained by making a connection assignment request to the representative port in the input interface and copying the connection assignment request to the entire group of output ports represented by the representative port in the scheduler section before making the switch connection assignment. It is done.
[0063]
In addition, the old cells are sent in order from the youngest input port at the input interface, and when the cells are output to the output line at the output interface, the cells transferred from the younger input port are output to the output line in order. This makes it possible to easily guarantee the order of cells.
[0064]
The input interface specifies the output port when making a cell transmission request (connection allocation request) to the scheduler unit. If the destination to which the cell is transferred is a high-speed output interface, specify the output port using the representative port. Do. The representative port is expressed using one of a plurality of output ports to which the high-speed output interface is connected.
The scheduler unit copies the connection allocation request addressed to the representative port to all output ports connected to the high-speed output interface to which the representative port belongs before performing connection allocation of the switch. By this conversion work, it is possible to perform connection assignment to any output port connected to the destination high-speed output interface. Furthermore, since one output port is assigned to one input port, connection assignment is not excessively performed even if a connection assignment request is copied.
[0065]
When connection allocation is performed, the input interface receives transmission permission from the scheduler unit, and transmits cells destined for output ports destined for transmission in order from the oldest cell. Since the high-speed input interface is connected to a plurality of input ports, a transmission permission addressed to the same output port may be simultaneously received from a plurality of input ports (the maximum number is the number of connected input ports). In this case, transmission is performed in order from the head of the queue of the cell addressed to the output port that has received transmission permission, in the number of transmission permission. At that time, the input ports are assigned so that the oldest cell is output to the youngest input port in order, and the newest cell is output to the input port with the highest port number. It is possible to guarantee the cell order by outputting the cells received from the younger input ports in order to the line side.
[0066]
By performing such switching control, it is possible to efficiently perform connection assignment of switches when an interface faster than the switch port speed is accommodated in the switch.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a switching device.
[Fig. 2] Input interface configuration diagram
FIG. 3 shows an example of connection between the switch unit and the input / output interface.
FIG. 4 shows an operation example of an input interface connected to one input port.
FIG. 5 shows an operation example of an input interface connected to a plurality of input ports.
FIG. 6 shows an example of the operation of the scheduler INF.
FIG. 7: Example of request counter conversion method
FIG. 8: Example of connection allocation conversion method
FIG. 9 is a diagram showing the configuration and operation of a conventional switching method.
FIG. 10 is a schematic diagram of a switching device.
[Explanation of symbols]
111-114 ... Input interface
121-124 ... Output interface
131: Request management unit
132: Request conversion unit
133: Switch connection determination unit
134 ... connection allocation conversion unit
14 ... Switch part
151 ... Send request
152 ... Transmission permission
161, 162 ... main signal data
17 ... Connection information
R31 ... Connection allocation request
R32 ... Connection allocation information
G33, G34 ... Connection allocation result
IN0-7 ... Input port
OUT0-7 ... Output port
21 ... line accommodation section
22 ... Destination determination unit
23 ... VOQ management department
24 ... Scheduler INF
211 ... Packet
212 ... cell
213: Cell and destination information
214 ... Cell
221, 222 ... Send request
223, 224 ... Transmission permission
41-44 ... Queue
401-464 ... cell
51-54 ... Queue
55 ... Output line
511-544 ... cell
91-94 ... cell

Claims (8)

A switching method that forms an interface for transferring data faster than the switch port speed by accommodating a plurality of switch ports ,
The input interface has a queue for temporarily storing cells for each destination information, and sends a transmission request signal to the scheduler unit.
The scheduler unit performs connection assignment and sends a transmission permission signal to the input interface, transmits connection information to the switch unit and switches the switch unit,
The input interface sends cells stored in the queue to the switch unit based on the sending permission signal, and the data is sent to the output interface according to switching of the switch unit ,
A switching method characterized in that one output port number of an output interface accommodating a plurality of output ports is defined as a representative port number, and the destination information is a representative port number. A switching method that forms an interface for transferring data faster than the switch port speed by accommodating a plurality of switch ports,
The input interface has a queue for temporarily storing cells for each destination information, and sends a transmission request signal to the scheduler unit.
The scheduler unit allocates connections and sends a transmission permission signal to the input interface, transmits connection information to the switch unit to switch the switch unit, and the input interface is stored in the queue in the switch unit. Cell is transmitted based on the transmission permission signal, the data is transmitted to the output interface according to the switching of the switch unit,
The input interface includes a line accommodation unit, a destination determination unit, a VOQ management unit, and a scheduler INF.
The line accommodating unit converts packet data into a fixed-length cell,
The destination determination unit assigns an output port number for each cell as destination information to the cell,
The VOQ management unit stores a cell in a queue for each destination information, transmits a transmission request to the scheduler unit via the scheduler INF, receives a transmission permission from the scheduler unit via the scheduler INF, Sending cells to the input port based on the sending permission,
A switching method characterized in that one output port number of an output interface accommodating a plurality of output ports is defined as a representative port number, and the destination information is a representative port number . The scheduler unit includes a request management unit, a request conversion unit, a switch connection determination unit, and a connection allocation conversion unit,
The request management unit has a request counter that is a matrix that stores the number of cells stored in the queue in association with input ports and destination information, and generates a connection allocation request based on the information of the request counter. Sent to the request converter,
The request conversion unit converts the connection allocation request into a second connection allocation request and transmits it to the switch connection determination unit,
The switch connection determination unit generates a connection allocation result based on the second connection allocation request, notifies the switch unit to switch the switch unit, and sends the connection allocation result to the connection allocation conversion unit. Send
The connection allocation conversion unit converts the connection allocation result into a second connection allocation result, sends the result to the input interface as the transmission permission signal, and transmits the second connection allocation result to the request management unit. ,
The switching method according to claim 1 , wherein the request management unit updates contents of the request counter based on the second connection allocation result. The scheduler unit includes a switch connection determination unit;
The input interface includes a request management unit, a request conversion unit, and a connection allocation conversion unit,
The request management unit has a request counter that is a matrix that stores the number of cells stored in the queue in association with input ports and destination information, and generates a connection allocation request based on the information of the request counter. Sent to the request converter,
The request conversion unit converts the connection allocation request into a second connection allocation request and transmits it to the switch connection determination unit,
The switch connection determination unit generates a connection allocation result based on the second connection allocation request, notifies the switch unit to switch the switch unit, and sends the connection allocation result to the connection allocation conversion unit. Send
The connection allocation conversion unit converts the connection allocation result into a second connection allocation result, sends the result to the input interface as the transmission permission signal, and transmits the second connection allocation result to the request management unit. ,
The switching method according to claim 1 , wherein the request management unit updates contents of the request counter based on the second connection allocation result. The connection allocation request is a matrix indicating the presence / absence of a cell whose destination information is the representative output port, and the conversion to the second connection allocation request is all accommodated in the output interface represented by the representative output port. 5. The switching method according to claim 3, wherein the presence / absence of a cell having the representative output port as destination information is copied to the output port. 6. The switching according to claim 3 , wherein the conversion from the connection allocation result to the second connection allocation result is aggregation of the connection allocation result into a representative port number. method. At the same time when sending a cell in which the same representative output port and destination information, claims, characterized in that sending the cell to the input port according to a predetermined order, and outputs the cell to the output line in accordance with a predetermined order at the output interface The switching system according to any one of claims 1 to 6 . The predetermined order is such that cells are sent to the younger input ports in order from the head of the queue and are output to the output line in order from the cells sent from the younger input ports at the output interface. The switching system according to claim 7 .

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