JP2005045626A - Data transfer system and multicast transferring method used in the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data transfer system capable of obtaining high multicast transfer performance with the scale of a small number of circuits. <P>SOLUTION: When a fixed-length packet is multiplexed and inputted from each of N input ports regardless of multicast/unicast, each of input control parts 1-1 to 1-N attaches an identification ID to the inputted packet and distributingly outputs the packet to crossbar switching parts 2-1 to 2-M. Each of the crossbar switching parts 2-1 to 2-M distributes the inputted packet to any of output control parts 3-1 to 3-N in the case of unicast, copies the packet to the output control parts 3-1 to 3-N of a copying object in the case of multicast and outputs a dummy to the output control parts 3-1 to 3-N other than the copying object. The output control parts 3-1 to 3-N collect inputted packets and output the inputted packets to N output ports while securing the sequentiality of the packets on the basis of the attached identification ID. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a data transfer system and a multicast transfer method used therefor, and more particularly to a multicast transfer method for transferring a multicast packet using a plurality of crossbar switches.

  Conventionally, in a packet switch, as shown in FIG. 11, N (N is a positive integer) input buffer units 71-1 to 71-N, a scheduler unit 72, a crossbar switch unit 73, and a frame assembly buffer 74-1 to 74-M and framing processing units 75-1 to 75-M.

  N input buffer units 71-171-N are provided corresponding to each of the N input lines # 1 to #N, and unicast packets and multicasts input via the corresponding input lines # 1 to #N. Store the packet.

  When the unicast packet is input from each of the N input buffer units 71-1 to 71-N, the crossbar switch unit 73 outputs M (M is a positive integer) output lines # 1 to # 1 as the transmission destinations. A unicast packet is output to any of #M, and when a multicast packet is input, the multicast packet is output to a plurality of M output lines # 1 to #M that are destinations .

  When a unicast packet and a multicast packet are input together in the scheduler unit 72, the input lines # 1 to #N and the output lines # 1 to #M do not compete with each other if the unicast packet is input. If it is a multicast packet, scheduling processing is performed so that the input lines # 1 to #N do not compete.

  The scheduler unit 72 greatly reduces the burden of scheduling processing by excluding a plurality of output lines # 1 to #M, which are multicast packet transmission destinations, from competition control targets. Since multicast packets are not copied in the input buffer units 71-1 to 71-N, the amount of data between the input buffer units 71-1 to 71-N and the switch unit 73 increases. And the input rate allowed for the multicast packet is prevented from decreasing.

  FIG. 12 is a diagram illustrating a configuration in which a plurality of the above-described switch units are provided. In FIG. 12, when a plurality of packets are collected to form a variable-length single IP (Internet Protocol) packet, the same switch surface (crossbar switch unit) 82-1 is used by using a flow identifier attached to the IP packet. Transfer the same flow at ~ 82-L. Here, the switch surfaces (crossbar switch units) 82-1 to 82-L are disposed between the separating unit 81-181-N and the multiplexing units 83-1 to 83-M.

  As a result, since packets belonging to the same flow are input to the same switch surface (crossbar switch unit) 82-1 to 82-L, the order of packets at the flow level is prevented from being reversed.

  As another method, when a so-called bit slice method is used in which a fixed-length packet (unicast packet or multicast packet) input via input lines # 1 to #N is divided in bit units in order from the beginning. A fixed-length packet is divided into L and sent to each of L switch surfaces (crossbar switch units) 82-1 to 82-L, and a plurality of switch surfaces (crossbar switch units) 82-1 to 82-L. Are used to transfer a plurality of divided data corresponding to one packet in parallel.

JP 2002-208938 A

  In the conventional multicast transfer method described above, in a configuration in which a plurality of switch surfaces (crossbar switch units) are provided, packets belonging to the same flow are input to the same switch surface (crossbar switch unit) using the flow identifier of the IP packet. Method is used.

  Therefore, in the conventional multicast transfer method, when a flow identifier is assigned to the same flow, it is determined which output line is routed for each flow, so that it is possible to prevent the packet order from being reversed at the flow level. It is also possible to cope with intra-crossbar switch copy of multicast packets.

  However, in the conventional multicast transfer method, there is a problem that the control unit for managing the flow identifier increases as the number of flows increases, and the transfer band of the packet is expanded with the expansion of the switch surface (crossbar switch unit). However, there is a problem that the transfer bandwidth of a single flow is suppressed within the transfer bandwidth of a single switch surface (crossbar switch unit).

  Further, in the conventional multicast transfer method, as another transfer method in a configuration in which a plurality of switch surfaces (crossbar switch units) are provided, a plurality of fixed-length packets are combined with a plurality of switch surfaces (crossbar switch units). A bit slice method for dividing can be used.

  The conventional multicast transfer method uses a plurality of switch planes (crossbar switch units) in parallel in the case of a bit slice technique in which a single fixed-length packet is divided into a plurality of sections according to a plurality of switch planes (crossbar switch units). Thus, the processing speed can be increased, and it is possible to cope with the copying of multicast packets in the crossbar switch section.

  However, in the conventional multicast transfer method, it is necessary to have the same header information (same destination information) for each piece of data obtained by dividing one fixed-length packet into a plurality of pieces, and the switch surface (crossbar switch unit) In proportion to the increase in the number, the ratio of the header information to the divided data also increases, resulting in a problem that the overhead increases.

  In addition, the conventional multicast transfer method has a problem that when the length of one fixed-length packet is increased in accordance with the increase in the number of switch surfaces (crossbar switch units), the packet transfer bandwidth is reduced. .

  Accordingly, an object of the present invention is to provide a data transfer system and a multicast transfer method used therefor that can solve the above-described problems and obtain high multicast transfer performance with a small circuit scale.

  Another object of the present invention is to provide a data transfer system capable of increasing the multicast transfer performance in proportion to an increase in the number of crossbar switches, and a multicast transfer method used therefor.

The data transfer system according to the present invention is provided corresponding to each of N (N is a positive integer) input ports, and stores a fixed-length unicast packet and multicast packet input from the corresponding input port. A function of assigning identification information to the stored unicast packet and the multicast packet, and a function of multiplexing the unicast packet and the multicast packet to which the identification information is added and distributing and outputting them to a plurality of output destinations. Including N input control units,
When the unicast packet is input from each of the N input control units, the unicast packet is output to any of the N output ports that are output destinations, and the multicast packet is input M (M is a positive integer) crossbar switch unit that outputs the multicast packet to a plurality of the N output ports that are the output destinations;
A function of storing the unicast packet and the multicast packet that are distributed and input from the M crossbar switch units; and the identification information provided by the input control unit with the stored unicast packet and the multicast packet. And N output control units for reconstructing them in the correct transfer order and outputting the unicast packet and the multicast packet to the output port.

  In another data transfer system according to the present invention, in the above configuration, the crossbar switch unit uses the information given to the multicast packet and copied to any one of the N output control units. Is output to a plurality of the N output ports as output destinations, and identification information having the order corresponding to information to be copied to any one of the N output control units. And a function of distributing corresponding to the output destination of the multicast packet.

The multicast transfer method according to the present invention is a fixed-length unicast packet input from a corresponding input port in N input control units provided corresponding to each of N (N is a positive integer) input ports. And multicast packets are stored, identification information is assigned to the stored unicast packets and multicast packets, and the unicast packets and multicast packets with the identification information are multiplexed and distributed to a plurality of output destinations. And
In the M (M is a positive integer) crossbar switch unit, when the unicast packet is input from each of the N input control units, the unicast packet is output to any of the N output ports that are output destinations. When a multicast packet is output and the multicast packet is input, the multicast packet is output to a plurality of the N output ports that are the output destinations.
In the N output control units, the unicast packet and the multicast packet that are distributed and input from the M crossbar switch units are stored, and the stored unicast packet and the multicast packet are stored in the input control unit. The unicast packet and the multicast packet are output to the output port by reconstructing in the correct transfer order using the identification information given in step (b).

  According to another multicast transfer method of the present invention, in the above processing, the crossbar switch unit uses the information given to the multicast packet and copied to any one of the N output control units. Is output to a plurality of the N output ports as output destinations, and identification information having the order corresponding to information to be copied to any one of the N output control units is sent to the multicast Sorted according to the packet output destination.

  That is, the first data transfer system of the present invention includes, in a plurality of crossbar switch configurations, N (N is a positive integer) input control units, M (M is a positive integer) crossbar switch units, N output control units.

  The input control unit stores, in the first buffer, fixed-length unicast packets and multicast packets that are multiplexed and input via the input ports, and the unicast packets are further distributed to N output ports. Each is stored in the second buffer. Different sequential identification IDs are assigned to the packets output from the first buffer of the multicast packet and the N second buffers of the unicast packet, and are arbitrarily distributed to the M crossbar switch units.

  When the unicast packet is input from each of the N input control units, the crossbar switch unit outputs the unicast packet to any of the N output ports that are the transmission destinations, and the multicast packet is input In this case, referring to the routing table, the multicast packet is output to a plurality of N output ports as the transmission destinations, and the dummy multicast packet is output to the remaining output ports of the output destinations.

  The output control unit stores the fixed-length unicast packet and the multicast packet that are multiplexed and input from each of the M crossbar switch units in the first buffer, and further distributes it for each of the N source input ports. Each is stored in a second buffer. In each of the N second buffers distributed for each source input port, the packets are rearranged in the case of a unicast packet based on the sequential identification ID given by the input control unit, and in the case of a multicast packet The packet is rearranged and the dummy packet is discarded.

  Similar to the above-described first data transfer system of the present invention, the second data transfer system of the present invention includes N input control units, M crossbar switch units, and N output control units. I have.

  The input control unit stores the fixed-length unicast packet and the multicast packet that are multiplexed and input through the input port in the first buffer, respectively, further distributes the unicast packet to N output ports, Store in the second buffer.

  The packets output from the N second buffers of the unicast packet are given the same sequential identification ID as the input control unit of the first data transfer system of the present invention described above, and the first of the multicast packets Sequential identification IDs and bitmaps are assigned to packets output from the buffers, and are arbitrarily distributed to M crossbar switch units.

  When the unicast packet is input from each of the N input control units, the crossbar switch unit outputs the unicast packet to any of the N output ports that are the destinations, and the multicast packet is input. In addition, using a sequential identification ID group and a bitmap, a multicast packet is attached to a destination based on the bitmap information and output to N output ports with a sequential identification ID corresponding to the bitmap information. To do.

  The output control unit stores the fixed-length unicast packet and the multicast packet that are multiplexed and input from each of the M crossbar switch units in the first buffer, and further distributes it for each of the N source input ports. Each is stored in the second buffer.

  In each of the N second buffers distributed for each source input port, based on the sequential identification ID given by the input control unit (unicast packet) and by the crossbar switch unit (multicast packet), Rearrange unicast packets and multicast packets.

  As a result, in the data transfer system of the present invention, packets can be transferred in a distributed manner to a plurality of crossbar switch units, so that all the packet transfer bandwidths of all crossbar switches can be used. .

  Further, in the data transfer system of the present invention, since the multicast packet is not copied in the input control unit and is copied in each of the plurality of crossbar switches, high multicast transfer performance can be obtained.

  Furthermore, in the data transfer system of the present invention, when a plurality of multiplexed packets are transferred by using a sequential identification ID given by the input control unit, the transfer order is reversed. Even if it exists, it becomes possible to reconstruct in the correct transfer order.

  The data transfer system according to the present invention has the following configuration and operation, so that it is possible to obtain high multicast transfer performance with a small circuit scale.

  Another data transfer system according to the present invention has the following configuration and operation, so that it is possible to obtain expandability that can increase multicast transfer performance in proportion to the increase in the number of crossbar switches. .

  Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a data transfer system according to an embodiment of the present invention. 1, the data transfer system according to the embodiment of the present invention includes N (N is a positive integer) input ports # 1 to #N and N input ports corresponding to N input ports # 1 to #N. Input control units 1-1 to 1-N, M (M is a positive integer) crossbar switch units 2-1 to 2-N, N output control units 3-1 to 3-N, , N output ports # 1 to #N connected to each of the N output control units 3-1 to 3-N.

  Each of the input control units 1-1 to 1-N receives a fixed-length packet multiplexed from each of the N input ports # 1 to #N without being classified into multicast / unicast, and an identification ID is input to the input packet. Is attached to the crossbar switch units 2-1 to 2-M.

  Each of the crossbar switch units 2-1 to 2-M distributes packets input from the input control units 1-1 to 1-N to any one of the output control units 3-1 to 3-N in the case of unicast. In the case of multicast, the packet is copied to the output control units 3-1 to 3-N to be copied, and the dummy is output to the output control units 3-1 to 3-N not to be copied.

  The output control units 3-1 to 3-N aggregate the packets input from the crossbar switch units 2-1 to 2-M, and packets based on the identification ID attached by the input control units 1-1 to 1-N. The packets are output to the N output ports # 1 to #N while ensuring the order.

  Thus, in the embodiment of the present invention, the multicast packets are aggregated into one buffer regardless of the number of flows on the input side, and the identification ID is uniquely assigned to the packets output from the buffer. The correct output order of packets can be easily constructed on the output side.

  In the embodiment of the present invention, in addition to the above operation, multicast packets are distributed to a plurality of crossbar switches, and copying is performed in each crossbar switch, thereby obtaining high multicast transfer performance with a small circuit scale. Can do.

  On the other hand, in the embodiment of the present invention, multicast packets input via input ports are distributed to a plurality of crossbar switches in units of packets, so that the packet transfer bandwidth increases as the number of crossbar switches increases, All of the bandwidth can be used. Therefore, in the embodiment of the present invention, it is possible to obtain extensibility capable of increasing the multicast transfer performance in proportion to the increase in the number of crossbar switches.

  Next, a data transfer system according to an embodiment of the present invention will be described. A data transfer system according to an embodiment of the present invention has the same configuration as the data transfer system according to the embodiment of the present invention shown in FIG.

  FIG. 2 is a block diagram showing the internal configuration of the input control unit according to an embodiment of the present invention. In FIG. 2, the input control unit 1 (corresponding to the input control units 1-1 to 1-N in FIG. 1) includes a multicast queue buffer 11, a unicast queue buffer 12, a queue buffer group 13 for an output control unit, a round It comprises a robin circuit 14, an identification ID management unit 15, and a packet distribution circuit 16.

  The multicast queue buffer 11 stores a fixed-length multicast packet that is multiplexed and input from the input port as a queue, and the unicast queue buffer 12 queues a fixed-length unicast packet that is multiplexed and input from the input port. Store as.

  The output control unit-destined queue buffer group 13 includes an output control unit # 1-destined queue buffer 13-1, an output control unit # 2-destined queue buffer 13-2,..., And an output control unit # N-destined queue buffer 13-N. Thus, one unicast queue is distributed and stored for N output control units # 1 to #N.

  The round robin circuit 14 outputs one queue based on priority among the queues output from the multicast queue buffer 11 and the queue buffer group 13 addressed to the output controller. The identification ID management unit 15 attaches different identification IDs to the queues output from the multicast queue buffer 11 and the output control destination queue buffer group 13.

  The packet distribution circuit 16 outputs packets corresponding to the queue output from the round robin circuit 14 and attached with the identification ID by the identification ID management unit 15 from the crossbar switch unit # 1 input path to the crossbar switch unit #M input path. Sort to go around.

  When fixed-length packets are multiplexed and input from the input port without distinguishing between multicast / unicast, the unicast packets are temporarily stored in the unicast queue buffer 12 as queues from the packet header information, and the multicast packets are queued. Accumulated in the multicast queue buffer 11.

  The queue stored in the unicast queue buffer 12 is output to the queue buffer group 13 for the output control unit. In the output control unit-destined queue buffer group 13, the input queues are distributed to the output control units # 1 to #N and stored in the output control units # 1 to # N-destined queue buffers 13-1 to 13-N, respectively. . The queues output from the output control units # 1 to #N queue buffers 13-1 to 13-N in the multicast queue buffer 11 and the output control unit destination queue buffer group 13 are input to the round robin circuit 14.

  The round robin circuit 14 determines the priority of the input queue and outputs one queue based on the priority. An identification ID output from the identification ID management unit 15 is attached to the queue output from the round robin circuit 14. The identification ID output by the identification ID management unit 15 is the queue output from the multicast queue buffer 11 and the output control units # 1 to #N in the output control unit-destined queue buffer group 13. The queue buffers 13-1 to 13-N The identification ID is different for each of the queues output from the queue ID, and the identification ID has an order for the queue output continuously from a certain queue buffer.

  For example, identification IDs such as i_0, i_1, i_2,..., I_n-1, i_n, i_0, i_1,. K_0, k_1, k_2,..., K_n-1, k_n, for queues continuously output from the output control unit # 1 queue buffer 13-1 in the control unit queue buffer group 13. For queues in which identification IDs such as k_0, k_1,... are continuously output from the output control unit # N-addressed queue buffer 13-N in the output control unit-specific queue buffer group 13, p_0, p_1 , P_2,..., P_n-1, p_n, p_0, p_1,.

  The queue to which the identification ID is attached is input to the packet distribution circuit 16. The packet distribution circuit 16 distributes the packet corresponding to the input queue to each of the M crossbar switch units # 1 to #M input paths. Packet distribution is performed so as to circulate in the direction from the crossbar switch unit # 1 input path to the crossbar switch unit #M input path. If there is a crossbar switch input path that is waiting for packet transfer or has a line interruption, avoid the crossbar switch input path and distribute the packet to the next crossbar switch input path. Sorting is performed.

  FIG. 3 is a block diagram showing the internal configuration of the crossbar switch unit according to one embodiment of the present invention. In FIG. 3, the crossbar switch unit 2 includes a round robin circuit 21, a unicast queue buffer 22, a multicast queue buffer 23, a routing table 24, and a crosspoint buffer control unit 25.

  The round robin circuit 21 outputs one packet based on the priority order from the multicast packet and the unicast packet multiplexed and input from the N input control units # 1 to #N connection paths.

  The unicast queue buffer 22 stores unicast packets output from the round robin circuit 21 as a queue, and the multicast queue buffer 23 stores multicast packets output from the round robin circuit 21 as a queue. The routing table 24 stores information on which output destination of the N output control units # 1 to #N connection paths is transferred to the multicast queue.

  The crosspoint buffer control unit 25 refers to the queue output from the unicast queue buffer 220 and the output control unit # 1 to #N connection path output from the multicast queue buffer 221 and with reference to the routing table 24 as the output destination. Cross points that are copied queues or N input control units that store dummy queues that are copied to output control units # 1 to #N connection paths that are not output destinations × N output control units Round-robin circuit 29 for each structure queue buffer 26-1 to 26-N, 27-1 to 27-N,..., 28-1 to 28-N, and output control units # 1 to #N. -1 to 29-N.

  Packets multiplexed and input from each of the N input control units # 1 to #N connection paths without being distinguished by multicast / unicast are input to the round robin circuit 21. The round robin circuit 21 determines the priority order of the input packet and outputs one packet based on the priority order.

  Packets output from the round robin circuit 21 are queued based on the header information, and are temporarily stored in the unicast queue buffer 22 if they are unicast packets, and are stored in the multicast queue buffer 23 if they are multicast packets.

  The queue output from the unicast queue buffer 22 is transferred to the crosspoint buffer control unit 25. The crosspoint buffer control unit 25 distributes the input queue to the output control units # 1 to # N-addressed queue management unit. Next, in each of the output control units # 1 to #N, the queue management units are further controlled by the input control units # 1 to #N transmission queue buffers 26-1 to 26-N depending on which input control unit # 1 to #N is transmitted. , 27-1 to 27-N,..., 28-1 to 28-N, and input control units # 1 to #N transmission queue buffers 26-1 to 26-N and 27-1 to 27-, respectively. Queues are accumulated in N,..., 28-1 to 28-N.

  The cross point buffer control unit 25 has a queue buffer configuration of a cross point structure addressed to N input control unit transmissions × N output control units. The queue output from the multicast queue buffer 23 refers to the routing table 24 and is copied to any of the output control units # 1 to #N in the cross point buffer control unit 25 according to the routing information. In addition, a dummy queue including the identification ID of the copy source queue and a dummy flag is output to any of the output control units # 1 to #N in the crosspoint buffer control unit 25 that are not to be copied in the routing information. Is done.

  In the output control units # 1 to #N in the cross point buffer control unit 25, as in the case of the unicast queue described above, the cross point buffer control is performed depending on which input control unit further transmits each. Are assigned to the input control units # 1 to #N transmission queue buffers in the unit 25, and are respectively input control units # 1 to #N transmission queue buffers 26-1 to 26-N, 27-1 to 27-N,. , 28-1 to 28-N.

  The queues output from the input control units # 1 to #N transmission queue buffers 26-1 to 26-N belonging to the output control unit # 1 destination queue management unit in the crosspoint buffer control unit 25 are sent to the round robin circuit 29-1. The queues output from the input control units # 1 to #N transmission queue buffers 27-1 to 27-N belonging to the output control unit # 2 destination queue management unit in the crosspoint buffer control unit 25 are round robin circuits 29-2. In addition, the queues output from the input control units # 1 to #N transmission queue buffers 28-1 to 28-N belonging to the output control unit # N-addressed queue management unit in the crosspoint buffer control unit 25 Are respectively input to the round robin circuit 29-N.

  Each of the round robin circuits 29-1 to 29-N in the crosspoint buffer control unit 25 determines the priority of the input queue, outputs one queue based on the priority, and sends a packet corresponding to the queue. Output to each of the corresponding N output control units # 1 to #N connection paths.

  FIG. 4 is a block diagram showing the internal configuration of the output control unit according to one embodiment of the present invention. In FIG. 4, the output control unit 3 includes a round robin circuit 31, a uni / multicast queue buffer 32, an identification ID detection control unit 33, an input control unit transmission queue buffer group 34, and a round robin circuit 35. Yes.

  The round robin circuit 31 outputs one packet based on the priority order among the multicast packets and unicast packets multiplexed and input from the M crossbar switch units # 1 to #M output paths. The uni / multicast queue buffer 32 stores the multicast packet and unicast packet output from the round robin circuit 31 as a queue.

  The input control unit transmission queue buffer group 34 includes N input control units # 1 to #N transmission queue buffers 34-1 to 34-N. The unicast queue and the multicast queue are divided into N input control units # 1. ~ #N Sort and store to sender.

  The identification ID detection control unit 33 is independent of each of the N input control units # 1 to #N transmission queue buffers 34-1 to 34-N in the input control unit transmission queue buffer group 34 in the case of a unicast queue. Based on the identification ID information, reconstruction is performed in the correct transfer order. In the case of a multicast queue, reconstruction is performed in the correct transfer order based on the identification ID information, and the dummy queue is discarded.

  The round robin circuit 35 outputs one queue based on the priority order from among the queues output from the N input control units # 1 to #N transmission queue buffers 34-1 to 34-N, and sends them to the queue. Outputs the corresponding packet to the output port.

  Packets multiplexed and input from each of the M crossbar switch units # 1 to #M output paths without being distinguished from multicast / unicast are input to the round robin circuit 31. The round robin circuit 31 determines the priority order of the input packet and outputs one packet based on the priority order.

  The packet output from the round robin circuit 31 is stored in the uni / multicast queue buffer 32 as a queue based on the header information. The queue stored in the uni / multicast queue buffer 32 is transferred to the input control unit transmission queue buffer group 34. The input control unit transmission queue buffer group 34 distributes the input queues to the input control units # 1 to #N transmission sources and stores them in the input control units # 1 to #N transmission queue buffers 34-1 to 34-N, respectively.

  Next, the identification ID detection control unit 33 stores the queues stored independently in the input control units # 1 to #N transmission queue buffers 34-1 to 34-N in the input control unit transmission queue buffer group 34, respectively. Search for an identification ID.

  A unicast queue or multicast queue matching the identification ID currently being searched can be detected in any of the input control units # 1 to #N transmission queue buffers 34-1 to 34-N in the input control unit transmission queue buffer group 34. In this case, the identification ID detection control unit 33 uses the input control units # 1 to #N transmission queue buffers 34-1 to 34-34 in the stored input control unit transmission queue buffer group 34 as a queue including the matching identification ID. N is taken out and input to the round robin circuit 35.

  The identification ID detection control unit 33 transfers the queue including the matching identification ID to the round robin circuit 35 and then updates the identification ID. Similarly, the identification ID detection control unit 33 updates the identification ID in the input control unit transmission queue buffer group 34 with the updated identification ID. The queues stored in the input control units # 1 to #N transmission queue buffers 34-1 to 34-N are searched.

  For example, when the identification ID of the currently searched unicast queue is k_0, when a queue including the identification ID is detected, the queue is extracted from the input control unit transmission queue buffer in the input control unit transmission queue buffer group 34. Input to the round robin circuit 35.

  Thereafter, the identification ID detection control unit 33 updates the identification ID to be searched to k_1 and searches the input control unit transmission queue buffer in the input control unit transmission queue buffer group 34 for a queue including the identification ID k_1. The identification ID is updated to k_2,..., K_n-1, k_n, k_0, k_1,. With this operation, order is ensured for a queue continuously output from a certain queue buffer (for example, the input control unit # 1 transmission queue buffer 34-1 in the input control unit transmission queue buffer group 34). be able to.

  The round robin circuit 35 determines the priority of the input queue, outputs one queue based on the priority, and outputs a packet corresponding to the queue to the output port.

  FIG. 5 is a diagram illustrating the operation of the queue buffer in the output control unit according to an embodiment of the present invention. The operation of the queue buffer in the output control unit according to the embodiment of the present invention will be described with reference to FIG.

  A multicast queue with identification ID i_0 to i_n, a unicast queue with identification ID k_0 to k_n, and a dummy queue with dummy ID D and identification ID i_1 / i_3 are in the input control unit transmission queue buffer group 34, respectively. A state in which the identification ID for starting search is i_0 (multicast queue) / k_0 (unicast queue) will be described. A1 to a10 indicate the order in which the queues are taken out from the input control unit # 1 transmission queue buffer 34-1 in the input control unit transmission queue buffer group 34.

  The identification ID detection control unit 33 searches the input control unit # 1 transmission queue buffer 34-1 in the input control unit transmission queue buffer group 34 for a queue whose identification ID is i_0 / k_0.

  In the operation of a1, when the identification ID detection control unit 33 detects the queue whose identification ID is k_0 as a result of the search, the queue whose identification ID is k_0 is designated as the input control unit # 1 in the input control unit transmission queue buffer group 34. The data is taken out from the transmission queue buffer 34-1 and output to the round robin circuit 35. After outputting the queue to the round robin circuit 35, the identification ID detection control unit 33 updates the identification ID to k_1, and searches for a queue whose identification ID is k_1.

  In the operation of a2, when the identification ID detection control unit 33 detects a queue with the identification ID k_1 as a result of the search, the queue with the identification ID k_1 is assigned to the input control unit # 1 in the input control unit transmission queue buffer group 34. The data is taken out from the transmission queue buffer 34-1 and output to the round robin circuit 35. After outputting the queue to the round robin circuit 35, the identification ID detection control unit 33 updates the identification ID to k_2, and searches for a queue whose identification ID is k_2.

  In the operation of a3, when the identification ID detection control unit 33 detects the queue whose identification ID is i_0 as a result of the search, the queue whose identification ID is i_0 is assigned to the input control unit # 1 in the input control unit transmission queue buffer group 34. The data is taken out from the transmission queue buffer 34-1 and output to the round robin circuit 35. After outputting the queue to the round robin circuit 35, the identification ID detection control unit 33 updates the identification ID to i_1 and searches for a queue whose identification ID is i_1.

  In the operation of a4, when the identification ID detection control unit 33 detects the queue with the identification ID i_1 as a result of the search, since the dummy flag D is attached, the queue with the identification ID i_1 is designated as the input control unit transmission queue. It is taken out from the input control unit # 1 transmission queue buffer 34-1 in the buffer group 34 and discarded. After discarding the queue, the identification ID detection control unit 33 updates the identification ID to i_2 and searches for a queue with the identification ID i_2.

  In the operation of a5, when the identification ID detection control unit 33 detects the queue having the identification ID k_2 as a result of the search, the queue having the identification ID k_2 is designated as the input control unit # 1 in the input control unit transmission queue buffer group 34. The data is taken out from the transmission queue buffer 34-1 and output to the round robin circuit 35. After outputting the queue to the round robin circuit 35, the identification ID detection control unit 33 updates the identification ID to k_3 and searches for a queue having the identification ID k_3.

  In the operation of a6, when the identification ID detection control unit 33 detects a queue with the identification ID i_2 as a result of the search, the queue with the identification ID i_2 is assigned to the input control unit # 1 in the input control unit transmission queue buffer group 34. The data is taken out from the transmission queue buffer 34-1 and output to the round robin circuit 35. After outputting the queue to the round robin circuit 35, the identification ID detection control unit 33 updates the identification ID to i_3 and searches for a queue having the identification ID i_3.

  In the operation of a7, when the identification ID detection control unit 33 detects a queue with the identification ID i_3 as a result of the search, since the dummy flag D is attached, the queue with the identification ID i_3 is designated as the input control unit transmission queue. It is taken out from the input control unit # 1 transmission queue buffer 34-1 in the buffer group 34 and discarded. After discarding the queue, the identification ID detection control unit 33 updates the identification ID to i_4 and searches for a queue having the identification ID i_4.

  In the operation of a8, when the identification ID detection control unit 33 detects the queue whose identification ID is i_4 as a result of the search, the queue whose identification ID is i_4 is identified as the input control unit # 1 in the input control unit transmission queue buffer group 34. The data is taken out from the transmission queue buffer 34-1 and output to the round robin circuit 35. After outputting the queue to the round robin circuit 35, the identification ID detection control unit 33 updates the identification ID to i_5 and searches for a queue having the identification ID i_5.

  In the operation of a9, when the identification ID detection control unit 33 detects a queue with the identification ID k_3 as a result of the search, the queue with the identification ID k_3 is assigned to the input control unit # 1 in the input control unit transmission queue buffer group 34. The data is taken out from the transmission queue buffer 34-1 and output to the round robin circuit 35. After outputting the queue to the round robin circuit 35, the identification ID detection control unit 33 updates the identification ID to k_4, and searches for a queue whose identification ID is k_4.

  In the operation of a10, when the identification ID detection control unit 33 detects the queue whose identification ID is i_5 as a result of the search, the queue whose identification ID is i_5 is assigned to the input control unit # 1 in the input control unit transmission queue buffer group 34. The data is taken out from the transmission queue buffer 34-1 and output to the round robin circuit 35. After outputting the queue to the round robin circuit 35, the identification ID detection control unit 33 updates the identification ID to i_6 and searches for a queue having the identification ID i_6.

  In this embodiment, by adopting the circuit configuration and control method as described above, high multicast transfer performance can be obtained with a small circuit scale.

  Next, a data transfer system according to another embodiment of the present invention will be described. A data transfer system according to another embodiment of the present invention has the same configuration as that of the data transfer system according to the embodiment of the present invention shown in FIG. 1, but includes input control units 1-1 to 1-N, a crossbar switch unit. The operations of the elements of 2-1 to 2-M and the output control units 3-1 to 3-N are different. Although not shown, the data transfer system according to another embodiment of the present invention includes input control units 4-1 to 4-N, crossbar switch units 5-1 to 5-M, and output control units 6-1 to 6-6. It shall consist of each element of -N.

  The input control units 4-1 to 4-N receive a fixed-length packet multiplexed from each of the N input ports # 1 to #N without being classified into multicast / unicast. The input control units 4-1 to 4-N attach different identification IDs when the input packet is a unicast queue, and attach M IDs and bitmaps when the input packet is a multicast queue. The packets are distributed and output to the units 5-1 to 5-M.

  The crossbar switch units 5-1 to 5-M distribute the packets input from the input control units 4-1 to 4-N to any one of the output control units 6-1 to 6-N in the case of unicast. Further, the crossbar switch units 5-1 to 5-M use the bitmaps attached by the input control units 4-1 to 4-N in the case of multicast, and copy target output control units 6-1 to 6-N. And the identification ID corresponding to the bitmap information is attached to each copy.

  The output control units 6-1 to 6-N aggregate the packets input from the crossbar switch units 5-1 to 5-M, and input control units 4-1 to 4-N or crossbar switch units 5-1 to 5-N. The packets are output to the output ports # 1 to #N while ensuring the order of the packets based on the identification ID attached with M.

  FIG. 6 is a block diagram showing an internal configuration of an input control unit according to another embodiment of the present invention. In FIG. 6, the input control unit 4 includes a multicast queue buffer 11, a unicast queue buffer 12, an output control unit-addressed queue buffer group 13, a round robin circuit 14, an identification ID management unit 41, a routing table 42, And a packet distribution circuit 16.

  The multicast queue buffer 11 stores a fixed-length multicast packet that is multiplexed and input from the input port as a queue, and the unicast queue buffer 12 queues a fixed-length unicast packet that is multiplexed and input from the input port. Store as.

  The output control unit-destined queue buffer group 13 distributes and stores the unicast queues to N output control units # 1 to #N. The round robin circuit 14 outputs one queue based on the priority among the queues output from the multicast queue buffer 11 and the output control destination queue buffer group 13.

  The identification ID management unit 41 assigns different identification IDs to the queues output from the multicast queue buffer 11 and the output control unit-destined queue buffer group 13 in the case of a unicast queue based on the stored contents of the routing table 42. Attach the ID group and bitmap to the multicast queue.

  The packet distribution circuit 16 outputs a packet corresponding to the queue output from the round robin circuit 14 and attached with an identification ID or a group of identification IDs and a bitmap in the identification ID management unit 41 from the crossbar switch unit # 1 input path to the crossbar switch Part #M Sorts in the direction of the input path.

  When fixed-length packets are multiplexed and input from the input port without distinguishing between multicast / unicast, the unicast packets are temporarily stored in the unicast queue buffer 12 as queues from the packet header information, and the multicast packets are queued. Accumulated in the multicast queue buffer 12.

  The queue accumulated in the unicast queue buffer 12 is output to the output control unit-addressed queue buffer group 13. The output control unit-destined queue buffer group 13 distributes the input queues to the output control units # 1 to #N and stores them in the output control units # 1 to # N-destined queue buffers 13-1 to 13-N, respectively. The queues output from the output control units # 1 to #N queue buffers 13-1 to 13-N in the multicast queue buffer 11 and the output control unit destination queue buffer group 13 are input to the round robin circuit 14.

  The round robin circuit 14 determines the priority of the input queue and outputs one queue based on the priority. When the queue output from the round robin circuit 14 is a multicast queue, an identification ID group and a bitmap output from the identification ID management unit 41 are attached. In FIG. 6, after the queue (white square) passes through the identification ID management unit 41, an identification ID group and a bitmap (shaded portion) are attached.

  When the queue output from the round robin circuit 14 is unicast, only the identification ID is attached. A queue to which an identification ID group and a bitmap (multicast queue) or an identification ID (unicast queue) is attached is input to the packet distribution circuit 16.

  The packet distribution circuit 16 distributes the packet corresponding to the input queue to each of the M crossbar switch units # 1 to #M input paths together with the identification ID group and the bitmap or the identification ID. Packet distribution is performed so as to circulate in the direction from the crossbar switch # 1 input path to the crossbar switch #M input path, and there is a crossbar switch input path that is in a packet transfer waiting state or a line is disconnected. Is executed so as to distribute the packet to the next crossbar switch unit input path while avoiding the crossbar switch unit input path.

  FIG. 7 is a block diagram showing an internal configuration of a crossbar switch unit according to another embodiment of the present invention. In FIG. 7, the crossbar switch unit 5 includes a round robin circuit 21, a unicast queue buffer 22, a multicast queue buffer 23, and a crosspoint buffer control unit 25.

  The round robin circuit 21 outputs one packet based on the priority order from the multicast packet and the unicast packet that are multiplexed and input from the N input control units # 1 to #N output paths.

  The unicast queue buffer 22 stores unicast packets output from the round robin circuit 21 as a queue, and the multicast queue buffer 23 stores multicast packets output from the round robin circuit 21 as a queue.

  The crosspoint buffer control unit 25 refers to the queue information output from the unicast queue buffer 22 and the bitmap information output from the multicast queue buffer 23 and attached to the queue. Cross-point structure queue buffer addressed to N connection paths, and stored in queues each having a copy attached with an identification ID corresponding to the bitmap information in each copy. And round robin circuits 29-1 to 29-N provided for each of the output control units # 1 to #N and the queue management units.

  Packets multiplexed and input from each of the N input control units # 1 to #N connection paths without being distinguished by multicast / unicast are input to the round robin circuit 21. The round robin circuit 21 determines the priority order of the input packet and outputs one packet based on the priority order. A packet output from the round robin circuit 21 is temporarily stored in the unicast queue buffer 22 as a queue if it is a unicast packet based on the header information, and is stored in the multicast queue buffer 23 as a queue if it is a multicast packet.

  The queue output from the unicast queue buffer 22 is transferred to the crosspoint buffer control unit 25. The crosspoint buffer control unit 25 distributes the input queue to the output control units # 1 to # N-addressed queue management unit.

  In each of the output control units # 1 to #N, the queue management units are further connected to input control units # 1 to #N transmission queue buffers 26-1 to 26-N, 27-1 to 27-2 depending on which input control unit transmits the queue. 27-N,..., 28-1 to 28-N, and input control units # 1 to #N transmission queue buffers 26-1 to 26-N, 27-1 to 27-N,. Accumulate in 28-1 to 28-N.

  The cross point buffer control unit 25 has a queue buffer configuration of a cross point structure addressed to N input control unit transmissions × N output control units. The queues output from the multicast queue buffer 23 are output control units # 1 to # 1 in the crosspoint buffer control unit 25 using the identification ID group attached to the queue (white square) and the bitmap information (hatched portion). It is copied to any of the queue management units addressed to #N.

  In this copy operation, the queue is copied to the output control units # 1 to #N in the crosspoint buffer control unit 25 corresponding to the valid copy flag in the bitmap, and the copy flag is enabled at the same time. The operation is such that the identification ID is attached to the corresponding queue.

  In each of the output control units # 1 to #N addressed queue management units in the crosspoint buffer control unit 25, as in the case of the unicast queue, the input control unit # 1 depends on which input control unit transmits the queue. To #N transmission queue buffers 26-1 to 26-N, 27-1 to 27-N,..., 28-1 to 28-N, respectively, and input control units # 1 to #N transmission queue buffer 26- 1 to 26-N, 27-1 to 27-N, ..., 28-1 to 28-N.

  The queues output from the input control units # 1 to #N transmission queue buffers 26-1 to 26-N belonging to the output control unit # 1 destination queue management unit in the crosspoint buffer control unit 25 are sent to the round robin circuit 29-1. The queues output from the input control units # 1 to #N transmission queue buffers 27-1 to 27-N belonging to the output control unit # 2 destination queue management unit in the crosspoint buffer control unit 25 are round robin circuits 29-2. In addition, the queues output from the input control units # 1 to #N transmission queue buffers 28-1 to 28-N belonging to the output control unit # N-addressed queue management unit in the crosspoint buffer control unit 25 Are respectively input to the round robin circuit 29-N.

  Each of the round robin circuits 29-1 to 29-N determines the priority order of the input queues, outputs one queue based on the priority order, and outputs N packets corresponding to the queue together with identification IDs. Are output to each of the output control units # 1 to #N.

  FIG. 8 is a block diagram showing an internal configuration of an output control unit according to another embodiment of the present invention. In FIG. 8, the output control unit 6 includes a round robin circuit 31, a uni / multicast queue buffer 32, an input control unit transmission queue buffer group 34, an identification ID detection control unit 61, and a round robin circuit 35. Yes.

  The round robin circuit 31 outputs one packet based on the priority order from among the multicast packets and unicast packets multiplexed and input from the M crossbar switch units # 1 to #M output paths. The uni / multicast queue buffer 32 stores the multicast packet and unicast packet output from the round robin circuit 31 as a queue.

  The input control unit transmission queue buffer group 34 distributes the unicast queue and the multicast queue to N input control units # 1 to #N transmission sources, and the input control units # 1 to #N transmission queue buffers 34-1 to 34-N. To store.

  The identification ID detection control unit 61 is independent of each of the N input control units # 1 to #N transmission queue buffers 34-1 to 34-N in the input control unit transmission queue buffer group 34 in the case of a unicast queue. Based on the identification ID information attached by the input control unit 4 and the identification ID information attached by the crossbar switch unit 5 in the case of a multicast queue, reconstruction is performed in the correct transfer order. The round robin circuit 35 outputs one queue based on the priority order from the queues output from the N input control units # 1 to #N transmission queue buffers 34-1 to 34-N, and the queues are output to the queues. Outputs the corresponding packet to the output port.

  Packets multiplexed and input from each of the M crossbar switch units # 1 to #M output paths without being distinguished from multicast / unicast are input to the round robin circuit 31. The round robin circuit 31 determines the priority order of the input packet and outputs one packet based on the priority order.

  The packet output from the round robin circuit 31 is stored in the uni / multicast queue buffer 32 as a queue based on the header information. The queue stored in the uni / multicast queue buffer 32 is transferred to the input control unit transmission queue buffer group 34. The input control unit transmission queue buffer group 34 distributes the input queues to the input control units # 1 to #N transmission sources and stores them in the input control units # 1 to #N transmission queue buffers 34-1 to 34-N, respectively.

  Next, the identification ID detection control unit 61 stores the queues stored independently in the input control units # 1 to #N transmission queue buffers 34-1 to 34-N in the input control unit transmission queue buffer group 34, respectively. Search for an identification ID.

  The identification ID detection control unit 61 is a unicast that matches the identification ID currently being searched in any of the input control units # 1 to #N transmission queue buffers 34-1 to 34-N in the input control unit transmission queue buffer group 34. When a queue or a multicast queue is detected, a queue including a matching identification ID is stored in the input control units # 1 to #N transmission queue buffers 34-1 to 34-34 in the input control unit transmission queue buffer group 34. N is taken out and input to the round robin circuit 35.

  The identification ID detection control unit 61 transfers the queue including the matching identification ID to the round robin circuit 35 and then updates the identification ID. Similarly, the identification ID detection control unit 61 updates the identification ID in the input control unit transmission queue buffer group 34 with the updated identification ID. The queues stored in the input control units # 1 to #N transmission queue buffers 34-1 to 34-N are searched.

  For example, when the identification ID of the currently searched unicast queue is k_0, when a queue including the identification ID is detected, the identification ID detection control unit 61 controls the input control in the input control unit transmission queue buffer group 34. Sections # 1 to #N are extracted from the transmission queue buffers 34-1 to 34-N and input to the round robin circuit 35.

  Thereafter, the identification ID detection control unit 61 updates the identification ID to be searched to k_1 and sets a queue including the identification ID k_1 to the input control units # 1 to #N transmission queue buffer 34-1 in the input control unit transmission queue buffer group 34. Search from ~ 34-N. The identification ID is updated to k_2,..., K_n-1, k_n, k_0, k_1,.

  With this operation, order is ensured for a queue continuously output from a certain queue buffer (for example, the input control unit #N transmission queue buffer 34-N in the input control unit transmission queue buffer group 34). be able to. The round robin circuit 35 determines the priority of the input queue, outputs one queue based on the priority, and outputs a packet corresponding to the queue to the output port.

  FIG. 9 is a diagram showing a format of an identification ID and a bitmap according to another embodiment of the present invention. In FIG. 9, this format is mainly divided into a bitmap and an identification ID group.

  The bitmap is a collection of flags indicating which output control unit 6-1 to 6-N among the N output control units 6-1 to 6-N is to be copied. When the identification ID management unit 41 shown in FIG. 6 recognizes the multicast queue, the identification ID management unit 41 refers to the routing table 42 and selects any one of the N output control units 6-1 to 6-N based on the routing information. Enable the copy flag. This bitmap is used as copy information of the multicast queue in the subsequent crossbar switch units 5-1 to 5-M.

  Another identification ID group is a collection of identification ID information of multicast queues corresponding to the destinations of the N output control units 6-1 to 6-N. When the identification ID management unit 41 recognizes the multicast queue, the identification ID management unit 41 refers to the routing table 42 and selects any one of the plurality of identification ID information among the N output control units 6-1 to 6-N based on the routing information. Register in the ID group and bitmap format.

  After registration, the identification ID management unit 41 updates any of a plurality of identification IDs among the N output control units 6-1 to 6-N based on the routing information. These identification ID groups are used as identification ID information of each copy destination when copying the multicast queue based on the bitmap in the subsequent crossbar switch units 5-1 to 5-M.

  In FIG. 6 and FIG. 9, the identification ID output from the identification ID management unit 41 is the queue output from the multicast queue buffer 11 and the output control # 1 to #N destination queue buffer 13 in the output control unit destination queue buffer group 13. It is an identification ID that is different for each of the queues output from -1 to 13-N, and an identification ID that has order for a queue that is output continuously from a certain queue buffer.

  For example, k_0, k_1, k_2,..., K_n-1 for the queues continuously output from the output control unit # 1 destination queue buffer 13-1 in the output control unit queue buffer group 13. , K_n, k_0, k_1,... For queues that are continuously output from the output control unit # N-destined queue buffer 13-N in the output control unit-destined queue buffer group 13. Identification IDs such as p_0, p_1, p_2,..., p_n-1, p_n, p_0, p_1,.

  The queues continuously output from the multicast queue buffer 11 are assigned identification IDs having order, but N IDs are output in order to update the identification ID based on the routing information obtained by referring to the routing table 41. The control units 6-1 to 6-N have different identification IDs.

  For example, when the output control unit 6-1 is addressed, identification IDs such as ia_0, ia_1, ia_2,..., Ia_n-1, ia_n, ia_0, ia_1,. In this case, identification IDs such as iz_0, iz_1, iz_2,..., Iz_n-1, iz_n, iz_0, iz_1,.

  FIG. 10 is a diagram showing the operation of the queue buffer in the output control unit according to another embodiment of the present invention. In FIG. 10, a multicast queue with identification IDs i_0 to i_n and a unicast queue with identification IDs k_0 to k_n are respectively stored in the input control unit # 1 transmission queue buffer 34-1 in the input control unit transmission queue buffer group 34. A state where the identification ID that is stored and the search is started is i_0 (multicast queue) / k_0 (unicast queue) will be described. B1 to b8 indicate the order in which the queues are taken out from the input control unit # 1 transmission queue buffer 34-1 in the input control unit transmission queue buffer group 34.

  The identification ID detection control unit 61 searches the input control unit # 1 transmission queue buffer 34-1 in the input control unit transmission queue buffer group 34 for a queue whose identification ID is i_0 / k_0.

  In the operation of b1, when the identification ID detection control unit 61 detects a queue whose identification ID is k_0 as a result of the search, the queue whose identification ID is k_0 is assigned to the input control unit # 1 in the input control unit transmission queue buffer group 34. The data is taken out from the transmission queue buffer 34-1 and output to the round robin circuit 35. After outputting the queue to the round robin circuit 35, the identification ID detection control unit 61 updates the identification ID to k_1 and searches for a queue having the identification ID k_1.

  In the operation of b2, as a result of the search, when the identification ID detection control unit 61 detects a queue with the identification ID k_1, the queue with the identification ID k_1 is assigned to the input control unit # 1 in the input control unit transmission queue buffer group 34. The data is taken out from the transmission queue buffer 34-1 and output to the round robin circuit 35. After outputting the queue to the round robin circuit 35, the identification ID detection control unit 61 updates the identification ID to k_2, and searches for a queue whose identification ID is k_2.

  In the operation of b3, when the identification ID detection control unit 61 detects a queue with the identification ID i_0 as a result of the search, the queue with the identification ID i_0 is assigned to the input control unit # 1 in the input control unit transmission queue buffer group 34. The data is taken out from the transmission queue buffer 34-1 and output to the round robin circuit 35. After outputting the queue to the round robin circuit 35, the identification ID detection control unit 61 updates the identification ID to i_1 and searches for a queue whose identification ID is i_1.

  In the operation of b4, when the identification ID detection control unit 61 detects a queue with the identification ID k_2 as a result of the search, the queue with the identification ID k_2 is designated as the input control unit # 1 in the input control unit transmission queue buffer group 34. The data is taken out from the transmission queue buffer 34-1 and output to the round robin circuit 35. After outputting the queue to the round robin circuit 35, the identification ID detection control unit 61 updates the identification ID to k_3 and searches for a queue having the identification ID k_3.

  In the operation of b5, when the identification ID detection control unit 61 detects a queue having the identification ID i_1 as a result of the search, the queue having the identification ID i_1 is designated as the input control unit # 1 in the input control unit transmission queue buffer group 34. The data is taken out from the transmission queue buffer 34-1 and output to the round robin circuit 35. After outputting the queue to the round robin circuit 35, the identification ID detection control unit 61 updates the identification ID to i_2 and searches for a queue having the identification ID i_2.

  In the operation of b6, when the identification ID detection control unit 61 detects a queue having the identification ID i_2 as a result of the search, the queue having the identification ID i_2 is designated as the input control unit # 1 in the input control unit transmission queue buffer group 34. The data is taken out from the transmission queue buffer 34-1 and output to the round robin circuit 35. After outputting the queue to the round robin circuit 35, the identification ID detection control unit 61 updates the identification ID to i_3 and searches for a queue having the identification ID i_3.

  In the operation of b7, when the identification ID detection control unit 61 detects a queue with the identification ID k_3 as a result of the search, the queue with the identification ID k_3 is assigned to the input control unit # 1 in the input control unit transmission queue buffer group 34. The data is taken out from the transmission queue buffer 34-1 and output to the round robin circuit 35. After outputting the queue to the round robin circuit 35, the identification ID detection control unit 61 updates the identification ID to k_4 and searches for a queue having the identification ID k_4.

  In the operation of b8, when the identification ID detection control unit 61 detects a queue having the identification ID i_3 as a result of the search, the queue having the identification ID i_3 is designated as the input control unit # 1 in the input control unit transmission queue buffer group 34. The data is taken out from the transmission queue buffer 34-1 and output to the round robin circuit 35. After outputting the queue to the round robin circuit 35, the identification ID detection control unit 61 updates the identification ID to i_4 and searches for a queue having the identification ID i_4.

  In the present embodiment, by performing the circuit configuration and the control method as described above, high multicast transfer performance can be obtained with a small circuit scale.

  As described above, in the present invention, the multicast packets are aggregated in one buffer regardless of the number of flows on the input side, and the identification ID is uniquely assigned to the packets output from the buffer. Can easily construct the correct output order of packets.

  In the present invention, in addition to the above processing, a multicast packet is distributed to a plurality of crossbar switches and copied in each crossbar switch, so that high multicast transfer performance can be obtained with a small circuit scale.

  Furthermore, in the present invention, multicast packets input via the input port are distributed to a plurality of crossbar switches in units of packets, so that the packet transfer bandwidth increases when the number of crossbar switches increases, and all of the transfer bandwidth is used. Therefore, it is possible to obtain a scalability capable of increasing the multicast transfer performance in proportion to the increase in the number of crossbar switches.

It is a block diagram which shows the structure of the data transfer system by embodiment of this invention. It is a block diagram which shows the internal structure of the input control part by one Example of this invention. It is a block diagram which shows the internal structure of the crossbar switch part by one Example of this invention. It is a block diagram which shows the internal structure of the output control part by one Example of this invention. It is a figure which shows operation | movement of the queue buffer in the output control part by one Example of this invention. It is a block diagram which shows the internal structure of the input control part by the other Example of this invention. It is a block diagram which shows the internal structure of the crossbar switch part by the other Example of this invention. It is a block diagram which shows the internal structure of the output control part by the other Example of this invention. It is a figure which shows the format of identification ID and a bitmap by the other Example of this invention. It is a figure which shows operation | movement of the queue buffer in the output control part by the other Example of this invention. It is a block diagram which shows the structural example of the conventional packet switch. It is a block diagram which shows the structural example at the time of providing the conventional switch part with two or more.

Explanation of symbols

1,1-1 to 1-N, 4 Input control unit 2,2-1 to 2-M, 5 Crossbar switch unit 3,3-1 to 3-N, 6 Output control unit
11, 23 Multicast queue buffer
12, 22 Unicast queue buffer
13 Output control unit-addressed queue buffer group 13-1 to 13-N Output control unit # 1 to # N-addressed queue buffers 14, 21,
29-1 to 29-N,
31,35 round robin circuit
15, 41 Identification ID management unit
16 Packet distribution circuit
24, 42 Routing table
25 Crosspoint buffer control units 26-1 to 26-N,
27-1 to 27-N,
28-1 to 28-N input control unit # 1 to #N transmission queue buffer
32 Uni / multicast queue buffer
33, 61 Identification ID detection control unit
34 Input control unit outgoing queue buffer group

Claims (16)

A function of storing N (N is a positive integer) input ports corresponding to each of the input ports, storing fixed-length unicast packets and multicast packets input from the corresponding input ports; N input control units each including a function of assigning identification information to the multicast packet, and a function of multiplexing the unicast packet and the multicast packet to which the identification information has been added and distributing and outputting them to a plurality of output destinations; ,
When the unicast packet is input from each of the N input control units, the unicast packet is output to any of the N output ports that are output destinations, and the multicast packet is input M (M is a positive integer) crossbar switch unit that outputs the multicast packet to a plurality of the N output ports that are the output destinations;
A function of storing the unicast packet and the multicast packet that are distributed and input from the M crossbar switch units; and the identification information provided by the input control unit with the stored unicast packet and the multicast packet. A data transfer system comprising: N output control units that are used to reconstruct in a correct transfer order and output the unicast packet and the multicast packet to the output port.   The input control unit includes a first storage unit that stores the unicast packet and the multicast packet input from the input port, and the N unicast packets output from the first storage unit. 2. The data transfer system according to claim 1, further comprising N second storage units that are sorted and stored for each output control unit.   The input control unit includes a function of assigning different and ordering identification information to packets respectively output from the first storage unit and the N second storage units. The data transfer system according to claim 2.   The input control unit adds information to be copied to any one of the N output control units and identification information having an order corresponding to the information to the multicast packet output from the first storage unit. The data transfer system according to claim 2, further comprising:   The crossbar switch unit includes: a routing table that stores output destination information of the multicast packet; and the multicast packet using the output destination information of the routing table. A function of outputting dummy packet information including the identification information having the order attached to the multicast packet to the remaining output ports that are not output to the multicast packet and output to a plurality of packets. The data transfer system according to any one of claims 1 to 4.   The crossbar switch unit uses the information given to the multicast packet and copied to any one of the N output control units to output the multicast packet among the N output ports that are output destinations. A function of outputting to a plurality of lines, and a function of distributing the identification information having the order corresponding to the information to be copied to any one of the N output control units according to the output destination of the multicast packet 5. The data transfer system according to claim 1, wherein the data transfer system is a data transfer system.   The output control unit outputs a third storage unit that shares and stores the unicast packet and the multicast packet that are distributed and input from the M crossbar switch units, and an output from the third storage unit. The N unicast packet and the multicast that are distributed and stored for each of the N input control unit transmission sources, respectively, and N fourth storage units. Or the data transfer system described.   The output control unit includes a function of discarding when dummy packet information including identification information having the order given to the multicast packet is output from the N fourth storage units. The data transfer system according to claim 7. N input control units provided corresponding to each of N (N is a positive integer) input ports store fixed-length unicast packets and multicast packets input from the corresponding input ports; Giving identification information to the stored unicast packet and the multicast packet, multiplexing the unicast packet and the multicast packet to which the identification information is given, and distributing and outputting to a plurality of output destinations,
In the M (M is a positive integer) crossbar switch unit, when the unicast packet is input from each of the N input control units, the unicast packet is output to any of the N output ports that are output destinations. When a multicast packet is output and the multicast packet is input, the multicast packet is output to a plurality of the N output ports that are the output destinations.
In the N output control units, the unicast packet and the multicast packet that are distributed and input from the M crossbar switch units are stored, and the stored unicast packet and the multicast packet are stored in the input control unit. A multicast transfer method, wherein the identification information given in step (b) is used to reconstruct the packet in a correct transfer order and output the unicast packet and the multicast packet to the output port.   The input control unit stores the unicast packet and the multicast packet input from the input port in a first storage unit, and the N unicast packets output from the first storage unit. 10. The multicast transfer method according to claim 9, wherein each of the output control units is sorted and stored in N second storage units.   11. The input control unit adds different and ordering identification information to packets respectively output from the first storage unit and the N second storage units. The multicast forwarding method described.   In the input control unit, information to be copied to any one of the N output control units and identification information having an order corresponding to the information are added to the multicast packet output from the first storage unit. The multicast transfer method according to claim 10, wherein:   In the crossbar switch unit, the multicast packet is output to a plurality of the N output ports as output destinations using the output destination information of the routing table storing the output destination information of the multicast packet. The dummy packet information including identification information having the order given to the multicast packet is output to the remaining output ports that are not output destinations of the multicast packet. 12. The multicast transfer method according to any one of 12.   In the crossbar switch unit, using the information given to the multicast packet and copied to any one of the N output control units, the multicast packet is output from the N output ports that are the output destinations. The identification information having the order corresponding to the information to be output to a plurality of copies and to be copied to any one of the N output control units is distributed according to the output destination of the multicast packet. The multicast transfer method according to claim 9.   In the output control unit, the unicast packet and the multicast packet distributed and input from the M crossbar switch units are shared and stored in a third storage unit, and output from the third storage unit. 15. The unicast packet and the multicast that are allocated to each of the N input control unit transmission sources and stored in N fourth storage units, respectively. Multicast forwarding method. The said output control part discards, when the dummy packet information containing the identification information with the said order given to the said multicast packet from the said N 4th storage part is output. 15. The multicast transfer method according to 15.

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