JP3758523B2 - Bidirectional ring network, node device, and bidirectional ring network control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a data communication network between computers, and more particularly to a bidirectional ring network in which a plurality of node devices are connected in a ring shape to communicate bidirectionally.
[0002]
[Prior art]
One type of computer network is a ring network. In general, a network in which multiple node devices are connected in a ring is called a ring network, but communication between each node device is possible only in one direction. A unidirectional ring network allows communication between each node device in both directions. Is called a bidirectional ring network. The ring network has a merit that it can be realized at low cost because the number of links is relatively small compared to the number of node devices.
[0003]
One problem in performing data communication over a ring network is avoiding deadlock. Deadlock refers to a "slack" state where processing cannot proceed further due to contention when acquiring resources. In general, when communicating by a packet switching method, each packet uses a buffer in the node device as a resource. If the resource dependency at this time forms a loop, there is a possibility of deadlock.
[0004]
A case where a deadlock occurs in a four-node ring network will be described. FIG. 10 shows a four-node ring network. Each node device 1001 (0) to 1001 (3) is connected one-to-one with a processing device 1003 (0) to 1003 (3) such as a computer, and holds only one packet input from an adjacent node device Buffers 1002 (0) to 1002 (3) and buffers 1004 (0) to 1004 (3) for holding packets input from the processing devices 1003 (0) to 1003 (3).
[0005]
If the input packet is not addressed to itself (the processing device connected to), the packet is forwarded to the next node device connected in the ring connection. However, in order to pass the packet to the next node device, the buffer of the next node device needs to be empty. Buffers 1002 (0) to 1002 (3) hold packets 1005 (0) to 1005 (3) in which unique destinations are described, respectively. The numbers 1, 2, 3, and 0 described in the packets 1005 (0) to 1005 (3) in the figure indicate destination node numbers. For example, the buffer 1002 (1) in the node device 1001 (1) holds the packet 1005 (2) to be communicated to the node device 1001 (2), but the buffer 1002 in the destination node device 1001 (2) In (2), another packet 1005 (3) is already held, and the node device 1001 (1) cannot deliver the packet 1005 (2) to the node device 1001 (2). Since a state similar to the above occurs in all the node devices, all the node devices fall into a slack state in which they wait for resources to be free, that is, a deadlock.
[0006]
This is the case when routing by storage exchange is performed, but in the case of wormhole routing, in order to maintain a link as a resource, a deadlock may occur as well.
[0007]
In "Parallel Computer Engineering" by Shoji Tomita (Shododo, 1996) p.42-p.47, an example of deadlock in a unidirectional ring network composed of four nodes is introduced as "deadlock in an interconnected network". The following solutions have been proposed.
[0008]
1. Dependency cycles are broken by channel sharing, ie virtual channels. Further, there is a method called a structured buffer pool configured to avoid contention in communication between arbitrary node pairs by increasing the number of buffers and the number of virtual channels in the node device.
[0009]
2. If a channel cannot be acquired, the acquired channel is released. However, in this case, a deadlock problem occurs with respect to the buffer for releasing the channel, so this method is not a fundamental solution to deadlock.
[0010]
3. Acquire all channels at once. This method requires centralized control and is difficult to realize by distributed control by each node device.
[0011]
4). A method in which a specific packet preferentially acquires a channel. Even if there is no possibility of deadlock, this method cannot avoid a specific packet preferentially acquiring a channel and becomes inefficient.
[0012]
5. Break the ring, that is, break the cycle that the resource dependency consists of. However, in a unidirectional ring network, a node device that cannot communicate directly is created, so it is necessary to take measures such as completing communication once at a relay node or adding a reverse ring.
[0013]
The most common deadlock avoidance methods are: It is to cut off the cycle in which there is a resource dependency using the virtual channel shown in. The basic concept of virtual channels is to virtually increase the number of channels between node devices without increasing the number of physical links, and to control resource acquisition so that channel dependencies do not constitute cycles. is there. This is realized by preparing a plurality of buffers in the node device and determining a buffer to be used according to a packet transmission destination or the like. These methods are described in detail in US patents such as Dally et al. (US patent 4,933,933 Torus routing chip).
[0014]
When deadlock is avoided by such a virtual channel, it is necessary to prepare buffers for the number of channels, and a control circuit for controlling a plurality of buffers is complicated. In addition, since the number of necessary channels depends on the number of nodes, there is a problem that the size of the network is limited by the configuration of the node device and the expandability is poor.
[0015]
Even in the case of the structured buffer pool, the problem of an increase in the number of buffers in the node device and the accompanying complicated control circuit is inevitable.
[0016]
Next, 5. The cutting of the ring will be described.
[0017]
FIG. 11 shows an example of avoiding deadlock by eliminating the dependency between specific channels by restricting the routing direction in a four-node bidirectional ring network to which ring connections in the reverse direction are added.
[0018]
FIG. 11 is a configuration diagram of a four-node bidirectional ring network. Node devices 1101 (0) to 1101 (3) connected in a ring shape capable of bidirectional communication via communication links C1 to C8 are in one-to-one correspondence with processing devices 1102 (0) to 1102 (3) such as computers, respectively. It is connected. Each node device 1101 (0) to 1101 (3) holds buffers 1103 (0) to 1103 (3) that hold packets received from the clockwise link and packets received from the counterclockwise link Buffers 1104 (0) to 1104 (3) and buffers 1105 (0) to 1105 (3) for holding packets received from directly connected processing devices 1102 (0) to 1102 (3), respectively . When a packet is received from an adjacent node device 1101 (0) to 1101 (3), the destination node number is confirmed and passed to the processing device 1102 (0) to 1102 (3) or the next node device 1101 ( Either 0) to 1101 (3) is forwarded.
[0019]
FIG. 12 is a directed graph representing channel dependency in the bidirectional ring network of FIG. C1 to C8 correspond to the links shown in FIG. In this figure, there are two cycles of C1->C2->C3->C4-> C1 and C5->C6->C7->C8-> C5, and there is a possibility of deadlock.
[0020]
Therefore, the following restrictions are set for routing. “Node device 1101 (0) does not relay packets, that is, only packets whose destination node number is always 0 are input to buffer 1103 (0) and buffer 1104 (0) of node device 1101 (0). FIG. 13 shows a graph of the channel dependency when the above restriction is applied. In FIG. 13, there is no dependency cycle, and deadlock is avoided.
[0021]
FIG. 14 shows a specific routing method in a case where deadlock avoidance is performed by the above routing direction restriction. As shown in the figure, the packet path is fixedly determined by the transmission source node and the transmission destination node. When the node device 1101 (0) is a transmission source node or a transmission destination node, there are a plurality of routes from which packets can be selected. In FIG. 14, the shorter route is selected and shown in such a case. There are two selectable paths of equal distance for communication from the node 1101 (0) to the node 1101 (2) and from the node 1101 (2) to the node 1101 (0), both of which are shown in FIG. Is marked.
[0022]
Thus, if the number of nodes is 4 or less, it is possible to determine the route of the packet so that it is deadlock free and the distance between the nodes is the shortest, "A Survey of Wormhole Routing Techniques in Direct Networks", LMNi and PKMcKinley, IEEE Computer, Feb 1993, p.62-76.
[0023]
In this way, when deadlock is avoided by cutting the ring, there is a problem that the packet path cannot be set at the shortest distance when the number of nodes increases, but the configuration of the node device is relatively simple, and the network There is an advantage that the configuration of the node device is not affected even when the scale of the node is large, that is, when the number of nodes is large.
[0024]
[Problems to be solved by the invention]
However, it has been pointed out as a problem that when deadlock is avoided by cutting the ring, the routing of the packet is fixed, and the route of the packet cannot be changed according to the state of the network. For example, ten node devices N0 to N9 with node numbers “0” to “9” are connected in a ring shape by bidirectional links in the order of node numbers, and the node device N0 with node number “0” is a disconnection point. Even when the network state changes and the traffic between the node devices N1 and N9 adjacent to the node device N0 at the disconnection point is the largest, the packets between the nodes N1 and N9 are However, there is a problem that transmission / reception continues through the most detour route.
[0025]
In addition, even if the packet route is designed to be changeable by recording it in a table, etc., it is necessary to manually design after rewriting the table, taking into account the channel dependency. There was a problem that could not be changed.
[0026]
OBJECT OF THE INVENTION
The present invention has been made in view of the above-mentioned problems, and its object is as follows.
[0027]
The first object is to make it possible to easily change the routing of a bidirectional ring network by simply performing a simple operation of changing the disconnection point of the dependency relationship to avoid deadlock.
[0028]
The second object is to enable the change of the dependency disconnection point by using a packet flowing through a normal path of the network without requiring a dedicated connection for instructing the node device to make the change.
[0029]
The third object is to enable the change of the above-mentioned dependency cut point while continuing the operation of the network.
[0030]
The fourth purpose is to set a specific link in the bi-directional ring network to an unused state by changing the disconnection point of the above dependency relationship so that the network can be easily expanded or maintained. It is in. A node device that achieves these objectives must be simple in configuration and can easily cope with an increase in the number of nodes in the network by using a node device having the same configuration.
[0031]
[Means for Solving the Problems]
In the present invention, an approach for avoiding deadlock by basically disconnecting a link is taken. For this reason, when the number of nodes is 5 or more, it is inevitable to select a detour route of the packet, but even when the number of nodes increases, a ring network can be configured with the same node device.
[0032]
In order to achieve the above object, a node device according to the present invention has a rewritable breakpoint recording register for recording a breakpoint of dependency in a bidirectional ring network,
An arithmetic unit that subtracts the value set in the cut point recording register from the destination node number of the received packet;
Furthermore, it has a computing unit that subtracts the value set in the cut point recording register from its own node number,
Route determining means for determining the destination of the packet based on the comparison of the output results of the two calculators.
[0033]
Furthermore, the node device according to the present invention has a configuration in which the contents are rewritten in accordance with the special packet for control flowing in the bidirectional ring network with respect to the cut point recording register.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
[0035]
FIG. 1 is a block diagram of a first embodiment of the present invention. 2 1 shows an example of a node device constituting a bidirectional ring network embodying the invention shown. The ring network configured by the node device is a bidirectional ring network.
[0036]
Here, in order to simplify the description, a storage and exchange type network will be described as an example. However, the following method replaces the packet with the first flit and controls to route the second and subsequent flits that do not have a destination address to the same destination as the first flit. It can also be applied to routing.
[0037]
The node device 101 has three input / output ports. The first input / output port includes an input port 114 and an output port 115, and is connected to a processing device (not shown) such as a computer. The input buffer unit 108 is a buffer unit that receives an input from the processing device via the input port 114, and the output control unit 109 controls the output of the packet to the processing device via the output port 115.
[0038]
The remaining two input / output ports are connected to another node device constituting the ring network. The second input / output port, ie, input port 116 and output port 117, is connected to another node device, and the third input / output port, ie, input port 119 and output port 118, is also connected to another node device. The Therefore, the connection between the input port 116 and the output port 118 is a connection that forms a one-way loop in the ring network, and the input port 119 and the output port 117 are connections that form a loop in the opposite direction to the above-described loop in the bidirectional ring network. It is. Here, a loop formed by the input port 116 and the output port 118 is called a forward loop, and a loop formed by the input port 119 and the output port 117 is called a reverse loop.
[0039]
The input buffer unit 110 that forms a forward loop has a buffer (not shown) that holds packets flowing through the forward loop. This buffer is controlled according to First In First Out rules. The input buffer unit 110 is connected to the output control unit 109 to the processing apparatus and the cut point recording register 102 in addition to the output control unit 112 that forms a forward loop.
[0040]
The input buffer unit 113 that forms a reverse loop has a buffer (not shown) that holds packets flowing through the reverse loop. This buffer is controlled according to First In First Out rules. The input buffer unit 113 is connected to the output control unit 109 to the processing apparatus and the cut point recording register 102 in addition to the output control unit 111 that forms a loop in the reverse direction.
[0041]
The input buffer unit 108 that receives input from the processing apparatus has a buffer (not shown) that holds packets. This buffer is controlled according to First In First Out rules. The input buffer unit 108 has means for writing to the destination recording register 103, receives an instruction from the route determination unit 105, and outputs control unit 112 that forms a forward loop and output control that forms a reverse loop. The packet can be output to the unit 111. In addition, a means for writing to the breakpoint recording register 102 is provided.
[0042]
The transmission destination recording register 103 is a register for recording the transmission destination node number of the packet in the input buffer unit 108. This value is input to the subtractor 107. The transmission destination recording register 103 needs to have a size sufficient to record the maximum value of the number of node devices constituting the network.
[0043]
The disconnection point recording register 102 is a register for recording a place where the dependency relationship is disconnected in order to avoid deadlock. This register can be written by the input buffer unit 110, the input buffer unit 113, and the input buffer unit 108, and the value is input to the subtracter 106 and the subtracter 107. The cut point recording register 102 is required to have a size sufficient to record the maximum number of node devices constituting the network.
[0044]
The node number recording register 104 is a register for recording a unique node number assigned to each node device in the ring network, and each packet uses this number as a destination. In the present invention, this value is assigned a number 0 to a certain node device constituting the ring network, and then, in ascending order such as 1, 2,... With respect to adjacent node devices along the forward loop. A number is assigned. The value of the node number recording register 104 is a value set before the network operation is started, and can be written by an instruction from the input buffer units 108, 110, and 113. However, the writing means is omitted in the figure. (It may be writable by a dedicated line.) The value of the node number recording register 104 is input to the subtractor 106 and the route determination means 105. The node number recording register 104 is required to have a size sufficient to record the maximum number of node devices constituting the network.
[0045]
The subtractor 106 is a circuit for subtracting the value of the cut point recording register 102 from the value of the node number recording register 104, and the output value is input to the route determining means 105. If the value of the breakpoint recording register 102 is larger than the value of the node number recording register 104, the result is output as a signed bit string in the form of 2's complement. The output value of the subtracter 106 corresponds to the number of hops in the forward direction from the node device at the disconnection point to the own node device. Note that since the subtractor 106 expresses the operation result as a signed bit string, the bit width of the output value is the maximum number of node devices constituting the network required by the node number recording register 104 and the cut point recording register 102. It is 1 bit or more larger than the number of bits required to record the value.
[0046]
The subtracter 107 is a circuit that subtracts the value of the cut point recording register 102 from the value of the transmission destination recording register 103, and the output value is input to the route determination means 105. If the value in the breakpoint recording register 102 is greater than the value in the destination recording register 103, the result is output as a signed bit string in the form of 2's complement. The output value of the subtracter 107 corresponds to the number of forward hops from the node device at the disconnection point to the node device to which the packet is transmitted. Since the subtractor 107 expresses the operation result as a signed bit string, the bit width of the output value is the maximum number of node devices that constitute the network, which is required for the transmission destination recording register 103 and the cut point recording register 102. It is 1 bit or more larger than the number of bits required to record the value.
[0047]
The route determining means 105 has a function of receiving input from the subtracter 107, the subtractor 106, and the node number recording register 104 and determining / instructing the output destination of the packet held in the input buffer unit 108. Note that the route determining means 105 having such a function can be realized at low cost by using a comparator or the like.
[0048]
Next, the operation of the node device 101 will be described.
[0049]
In the forward loop, the input buffer unit 110 receives a packet flowing through the loop. The input buffer unit 110 determines the destination node number of the received packet, and if it matches the node device specific number, the packet is output to the processing device via the output control unit 109 and the output port 115. . If the destination node number is different from the node device-specific number, the packet is delivered to the next node device via the output control unit 112 and the output port 118 along the loop direction. The node device specific number is equal to the value held in the node number recording register 104. In the figure, it is depicted that the value of the node number recording register 104 is read and judged, but the input buffer unit 110 may hold a copy of this value.
[0050]
In the reverse loop, the input buffer unit 113 receives a packet flowing through the loop. In the input buffer unit 113, as in the case of the forward loop, the destination node number of the received packet is compared with the node device specific number. If they match, the packet is passed to the processing device via the output control unit 109 and the output port 115. If they do not match, the packet follows the loop in the reverse direction and the output control unit 111 and the output port. 117 to another node device.
[0051]
The operation up to this point is the same as that of a conventional node device constituting a bidirectional ring network. Next, the operation when the node apparatus 101 receives a packet from the processing apparatus will be described.
[0052]
A packet input from the processing device is input to the input buffer unit 108. In the input buffer unit 108, the transmission destination node number of the packet is read out and input to the transmission destination recording register 103.
[0053]
Next, the subtracter 107 subtracts the value of the cut point recording register 102 from the written value of the transmission destination recording register 103 and inputs the result to the route determination means 105.
[0054]
In addition to the subtraction result of the subtractor 107, the route determination means 105 uses the result of subtracting the value of the cut point recording register 102 from the value of the node number recording register 104 by the subtractor 106 and the value of the node number recording register 104. The output destination of the packet received as input and held in the input buffer unit 108 is determined.
[0055]
A method for determining the output destination of the packet by the route determining means 105 will be described with reference to the flowchart of FIG. However, in this embodiment, it is assumed that the transmission source node number and the transmission destination node number are the same, that is, communication to itself cannot occur. In the route determination method according to FIG. 2, the node device having the same number as the value specified in the cut point recording register 102 is the cut point of the dependency relationship of both the forward loop and the reverse loop.
[0056]
First, at step 201, the value of the subtractor 106 is confirmed. This value is the difference between the values of the node number recording register 104 and the cut point recording register 102. When this value is 0, this node device 101 itself becomes a disconnection point of the dependency relationship between both the forward loop and the backward loop. In this case, as shown in step 202, the output destination of the packet is arbitrary. That is, no deadlock occurs regardless of which loop the packet is sent out.
[0057]
If the sending direction is arbitrary, it is necessary to determine the sending direction by some method. For example, a method such as fixedly flowing in the forward direction or the reverse direction, using the forward direction and the reverse direction alternately, or determining by determining which of the forward direction and the reverse direction has the smaller number of hops of the node device. There is. The input buffer unit 108 transmits the packet to the output control unit 112 when the transmission direction is determined to be the forward loop, and to the output control unit 111 when the transmission direction is determined to be the reverse loop.
[0058]
Next, at step 203, the value of the subtracter 107 is confirmed. This value is the difference between the values of the transmission destination recording register 103 and the cut point recording register 102. When this value is 0, the node device to which the packet is transmitted is the disconnection point of the dependency relationship between both the forward loop and the reverse loop. In this case, as shown in step 204, the output destination of the packet is arbitrary. That is, no deadlock occurs regardless of which loop the packet is sent out. In step 204, as in step 202, the packet transmission direction is determined according to some rule.
[0059]
Next, at step 205, the output value of the subtractor 106 is compared with the output value of the subtractor 107. If the output of the subtractor is a negative value, it is output in the form of 2's complement. In step 205, each output value is treated as an unsigned integer and compared. Therefore, when the subtraction result is a negative number, it is treated as a larger numerical value than when the subtraction result is a positive number. If the result of this comparison is that the output value of the subtractor 106 is greater than the output value of the subtractor 107, the sending direction is determined to be a reverse loop in step 206. In this case, the packet in the input buffer unit 108 is output to the output control unit 111. On the other hand, if the output value of the subtractor 106 is smaller than the output value of the subtractor 107, the sending direction is determined to be a forward loop in step 207. In this case, the packet in the input buffer unit 108 is output to the output control unit 112.
[0060]
Next, taking a case where a 6-node bidirectional ring network is configured using the node device 101 according to the present invention as an example, the determination of the routing direction will be described with reference to FIG.
[0061]
FIG. 3 is a block diagram of a 6-node bidirectional ring network. Node devices 301 (0) to 301 (5) according to the present invention are connected in a ring shape by links C1 to C12. A processing device such as a computer is connected to each of the node devices 301 (0) to 301 (5), but is omitted in FIG.
[0062]
Here, a case where 2 is recorded in the cut point recording register 102 is taken as an example. In this case, the node device 301 (2) having the node number 2 is a node device that cuts off the dependency relationship between the forward loop and the reverse loop. FIG. 4 shows the link dependency in this case. Since the dependency relationship is disconnected in the node device 301 (2), there is no dependency relationship from the link C2 to the link C3. In other words, for a packet that reaches the node device 301 (2) using the link C2, the node device 301 (2) is always the transmission destination node, and the node device 301 (3) uses the forward loop link C3. Will not be output. Similarly, regarding the loop in the reverse direction, there is no dependency from the link C10 to the link C11. Therefore, a packet that reaches the node device 301 (2) using the reverse loop link C10 is always the destination device of the node device 301 (2), and the node device 301 (2) uses the reverse loop link C11. It is never sent to 301 (1).
[0063]
The operation of the route determination unit 105 will be described more specifically. The following shows how the route is actually determined in the four communication patterns. Here, since the number of nodes constituting the ring network is 6, the bit widths of the cut point recording register 102, the transmission destination recording register 103, and the node number recording register 104 are 3 bits, and the output bit widths of the subtractor 106 and the subtractor 107 Is 4 bits.
[0064]
(1) When sending a packet from the node device 301 (3) to the node device 301 (5). At this time, the output of the subtractor 107 is 5-2 = 3 (binary number 0011), and the output of the subtractor 106 is 3-2 = 1 (binary number 0001). Since the output of the subtractor 106 is smaller than the output of the subtracter 107 in step 205 of FIG. 2, the packet is sent to the forward loop according to step 207.
[0065]
(2) When sending a packet from the node device 301 (3) to the node device 301 (1). At this time, the output of the subtractor 107 is 1-2 = -1 (1111 when expressed in binary with 2's complement), and the output of the subtractor 106 is 3-2 = 1 (0001 in binary). Since the comparison in step 205 in FIG. 2 is treated as an unsigned integer, it is determined that the output value (1111) of the subtractor 107 is larger than the output value (0001) of the subtractor 106, and the packet is forward looped according to step 207. Is sent out.
[0066]
(3) When sending a packet from the node device 301 (1) to the node device 301 (0). At this time, the output of the subtractor 107 is 0-2 = -2 (1110 when expressed in binary with 2's complement), and the output of the subtractor 106 is 11 = 11 when expressed with 1-2 = -1 (in binary with 2's complement). ) Since the comparison in step 205 of FIG. 2 is treated as an unsigned integer, it is determined that the output value (1110) of the subtractor 107 is smaller than the output value (1111) of the subtractor 106, and the packet is subjected to a backward loop according to step 206. Is sent out.
[0067]
(4) When sending a packet from the node device 301 (2) to the node device 301 (4). At this time, since the output of the subtracter 106 becomes 2-2 = 0 in step 201, the packet transmission direction is arbitrary according to step 202. In this case, the sending direction is determined by another method.
[0068]
FIG. 5 shows which route is selected by the route determination means 105 when the value held in the cut point recording register 102 is 2 in the 6-node bidirectional ring network using the node device 101 according to the present invention. The packet is shown for each source node number and destination node number.
[0069]
Next, a description will be given of a case in which the dependency cut point is changed during operation in the bidirectional ring network configured using the node device 101. FIG. In the bi-directional ring network according to the present invention, the network management packet from the processing device propagates on a normal loop instead of instructing each node device by a dedicated line to move the dependency cut point. It becomes possible to do it.
[0070]
In the 6-node bidirectional ring network shown in FIG. 3 (using the node device of FIG. 1 according to the present invention as the node device), the disconnection point of the dependency relationship is changed from the node device 301 (2) to the node device 301 (1). This is an example of the case. The node devices 301 (0) to 301 (5) are connected in a ring shape by links C1 to C12, and each of the node devices 301 (0) to 301 (5) is connected to a processing device such as a computer. It is omitted in the figure.
[0071]
At the first time, 2 is recorded in the cut point recording register 102 in the node devices 301 (0) to 301 (5). At this time, an instruction to move the disconnection point of the dependency relationship is input from the node device 301 (2) to the network as a normal communication packet. Hereinafter, this packet is referred to as a control special packet.
[0072]
The operation of the special packet for control in the node device 301 (2) will be described with reference to FIG. The special packet for control is input to the input buffer unit 108 using the input port 114 connected to the processing device. When the input buffer unit 108 determines that the packet is a control special packet, the input buffer unit 108 determines the output destination of the packet. In this case, the output destination of the packet is not set by the route determining means 105, but is determined by the input buffer unit 108 so that the dependency cut point moves along a loop opposite to the moving direction. In this example, since the cut point of the dependency relationship is moved in the same direction as the backward loop (that is, the direction in which the number unique to the node device is -1), the packet itself goes around the ring along the forward loop. For this purpose, the input buffer unit 108 sends a packet to the output control unit 112 that forms a forward loop. Simultaneously with the transmission of the packet, the input buffer unit 108 updates the content of the cut point recording register 102 from 2 to 1. Thereafter, in the node device 301 (2), the route is determined on the assumption that the dependency disconnection point is in the node device 301 (1).
[0073]
Next, the operation after the node device 301 (3) receives the control special packet will be described with reference to FIG. The special packet for control is input to the input buffer unit 110 from the input port 116 of the forward loop. Since the buffer in the input buffer unit 110 performs service according to the First In First Out rule, no special processing is performed until the service order of the control special packet is reached. When in service order, this packet is passed to the output control unit 112 along the forward loop. At the same time, the input buffer unit 110 rewrites the contents of the cut point recording register 102 from 2 to 1. Thereafter, in the node device 301 (3), a route is determined on the assumption that the dependency disconnection point is in the node device 301 (1).
[0074]
In the node devices 301 (4), 301 (5), and 301 (0), the control special packet is processed in the same manner as the node device 301 (3).
[0075]
Assuming a state immediately after the control special packet is serviced in the node device 301 (4), the dependency relationship of the link in the transient state is shown. At this time, in the node devices 301 (2), 301 (3), and 301 (4), the value of the disconnection point register 102 is updated to 1, so that the disconnection point of the dependency relationship is the node device 301 (1). We recognize that there is. In the node devices 301 (5), 301 (0), 301 (1), the value of the disconnection point recording register 102 is 2, so that the dependency disconnection point is in the node device 301 (2). It has recognized.
[0076]
First, focusing on the forward loop, the node device 301 (2), 301 (3), 301 (4) recognizes that the node device 301 (1) is a dependency disconnection point. Depending on the packets transmitted by (2), 301 (3), and 301 (4), a link dependency relationship is formed in the order of C3 → C4 → C5 → C6 → C1. On the other hand, since the node devices 301 (5), 301 (0), 301 (1) recognize that the node device 301 (2) is a dependency cut point, the node devices 301 (5), 301 (0) ), 301 (1) form a dependency relationship such as C6 → C1 → C2. At this time, since there is no dependency relationship of C2 → C3, a cycle is not formed and deadlock cannot occur.
[0077]
Next, paying attention to the loop in the reverse direction, the node device 301 (2), 301 (3), 301 (4) recognizes that the node device 301 (1) is a dependency disconnection point. Link dependencies such as C9 → C10 → C11 are formed by the packets transmitted by 301 (2), 301 (3), and 301 (4). On the other hand, since the node devices 301 (5), 301 (0), 301 (1) recognize that the node device 301 (2) is a dependency cut point, the node devices 301 (5), 301 (0) ), 301 (1) form a dependency relationship such as C12 → C7 → C8 → C9 → C10. At this time, since there is no dependency relationship of C11 → C12, a cycle is not formed and a deadlock cannot occur.
[0078]
Therefore, in this bi-directional ring network, no deadlock can occur even when the control special packet circulates the network.
[0079]
Next, the operation after the control special packet arrives at the node device 301 (1) will be described with reference to FIG. The special packet for control is input to the input buffer unit 110 from the input port 116 of the forward loop. Since the buffer in the input buffer unit 110 performs service according to the First In First Out rule, no special processing is performed until the service order of the control special packet is reached. When the service order is reached, the input buffer unit 110 recognizes that the new dependency cut point indicated by the control special packet matches the node number of itself, and discards the packet. At the same time, the input buffer unit 110 rewrites the contents of the cut point recording register 102 from 2 to 1. Thereafter, in the node device 301 (1), the route is determined on the assumption that the cut point of the dependency relationship is in the node device 301 (1).
[0080]
As described above, when the control special packet reaches the node (301) along the forward loop from the node device 301 (2), all the node devices 301 (0) to (5) constituting the ring network are obtained. ) Recognizes that the dependency cut point is at 301 (1), and the route of the packet in the network is changed. However, when the network adopts wormhole routing, it should be noted that the processing needs to be completed in units of packets when updating the cut point recording register 102 in each node.
[0081]
When moving the dependency cut point from the node device 301 (2) to the node device 301 (3) along the forward loop, the control packet for control is moved from the node device 301 (2) along the reverse loop. This can be realized by reaching the node device 301 (3).
[0082]
Next, as a second embodiment of the present invention, the claims 3, 4 An example in which the invention shown in FIG.
[0083]
FIG. 6 claims 3, 4 It is an example of the node apparatus 101a which comprises the bidirectional | two-way ring network which implemented this invention concerning. The node device 101a is the claim 1 shown in FIG. 2 The configuration is almost the same as that of the node device 101 constituting the bidirectional ring network implementing the invention. Therefore, description of common points is omitted, and only differences are described.
[0084]
In the node device 101a shown in FIG. 6, a node number recording register 601 and an adder 602 are added as compared with the node device 101 shown in FIG. 1, and the route determining means 105a is replaced with the route determining means 105a. I have. The node number recording register 601 is a register for recording the number of node devices constituting the ring network. The value in the node number recording register 601 is a value set before the start of network operation, and can be written according to instructions from the input buffer units 108, 110, and 113. However, the writing means is omitted in the figure. (It may be writable by a dedicated line.) The value of the node number recording register 601 is input to the adder 602. The node number recording register 601 needs to have a size sufficient to record the maximum number of node devices constituting the network.
[0085]
The adder 602 is a circuit for adding the value of the node number recording register 601 and the output value of the subtractor 106, and the output value is input to the route determining means 105a. Adder 602 requires the same bit width as subtractor 106.
[0086]
Next, the operation of the node device 101a will be described.
[0087]
The operation when the node device 101a receives a packet from another node device configuring the ring network is not different from the case of the node device shown in FIG. The same is true when a packet is received from the processing device, but the operation of the route determination means 105a is different.
[0088]
A method for determining the output destination of the packet by the route determining means 105a will be described with reference to the flowchart of FIG. However, in this embodiment, it is assumed that the transmission source node number and the transmission destination node number are the same, that is, communication to itself cannot occur.
[0089]
In the route determination method according to FIG. 7, the node device having the same number as the value specified in the disconnection point recording register 102 becomes the disconnection point of the forward loop dependency relationship, and is set along the forward loop of the node device. The node device connected first is the disconnection point of the loop dependency in the reverse direction.
[0090]
First, at step 701, the value of the subtractor 106 is confirmed. This value is the difference between the values of the node number recording register 104 and the cut point recording register 102. When this value is 0, the node device 101a itself is a disconnection point of the forward loop dependency. Therefore, if a forward loop is used, any node device in the network can communicate. In addition, the node device that is only one ahead in the forward direction is the disconnection point of the loop dependency in the reverse direction. Therefore, it is possible to communicate with any node device in the network by a loop in the reverse direction. In this case, as shown in step 702, the output destination of the packet is arbitrary. No matter what loop the packet is sent out, deadlock will not occur.
[0091]
When the sending direction is arbitrary, it is necessary to determine the sending direction by some method as in the case of the operation example of the node device 101 shown in FIG. The input buffer unit 108 outputs the packet to the output control unit 112 when the sending direction is determined to be the forward loop, and to the output control unit 111 when the sending direction is determined to be the reverse loop.
[0092]
Next, at step 703, the value of the subtracter 106 is confirmed again. When this value is 1, the node device 101a itself is a disconnection point of the loop dependency in the reverse direction. Therefore, if a loop in the reverse direction is used, any node device in the network can communicate. Also, the node device that is only one ahead in the reverse direction is the break point of the forward loop dependency. Therefore, it is possible to communicate with any node device in the network even by a forward loop. In this case, as shown in step 704, the output destination of the packet is arbitrary. No matter what loop the packet is sent out, deadlock will not occur.
[0093]
If the node number of the node device 101a itself is 0, even if it is the disconnection point of the loop dependency in the reverse direction, it cannot be found in step 703. In order to find this, the output value of the adder 602 is confirmed in the next step 705. This value is the sum of the values of the node number recording register 601 and the subtractor 106. This value is 1 when the number of node devices constituting the network (that is, the value of the node number recording register 601) is N, the value of the cut point recording register 102 is N-1, and the value of the node number recording register 104 is Only in case of 0. Since the node device 101a becomes the disconnection point of the loop dependency in the reverse direction, the sending direction is arbitrary as in step 703 (step 706).
[0094]
Next, at step 707, the output value of the subtracter 107 is confirmed. This value is the difference between the values of the transmission destination recording register 103 and the cut point recording register 102. When this value is 0, the destination node is a disconnection point of the forward loop dependency, and communication is possible using the forward loop. However, since the node device connected only one ahead along the forward loop from this node device is the disconnection point of the dependency relationship of the reverse loop, communication is performed using the reverse loop. It is impossible to do. In this case, in step 708, the sending direction is determined to be a forward loop. The packet in the input buffer unit 108 is output to the output control unit 112.
[0095]
Next, in step 709, the output value of the subtractor 106 is compared with the output value of the subtractor 107. If the output of the subtractor is negative, it is output in the form of 2's complement. In step 709, each output value is treated as an unsigned integer and compared. Therefore, when the subtraction result is a negative number, it is treated as a larger numerical value than when the subtraction result is a positive number. As a result of the comparison, if the output value of the subtractor 106 is larger than the output value of the subtractor 107, in step 710, the sending direction is determined to be a reverse loop. In this case, the packet in the input buffer unit 108 is output to the output control unit 111. On the other hand, if the output value of the subtractor 106 is smaller than the output value of the subtractor 107, the sending direction is determined to be a forward loop in step 711. In this case, the packet in the input buffer unit 108 is output to the output control unit 112.
[0096]
Next, taking a case where a 6-node bidirectional ring network is configured using the node device 101a according to the present invention as an example, determination of the routing direction will be described with reference to the drawings.
[0097]
The 6-node bidirectional ring network is configured in the same way as when the node device 101 according to FIG. 1 is used. For this reason, the same FIG. 3 is used for the description. The node devices 301 (0) to 301 (5) are connected in a ring shape by links C1 to C12. A processing device such as a computer is connected to each of the node devices 301 (0) to 301 (5), but is omitted in FIG.
[0098]
Here, a case where 2 is recorded in the cut point recording register 102 is taken as an example. In this case, the node device 301 (2) with the node number 2 becomes a node that cuts off the dependency of the forward loop, and the node device 301 (3) with the node number 3 has the dependency of the loop in the reverse direction. It becomes a node to be disconnected. FIG. 8 shows the link dependency in this case. In the node device 301 (2), the dependency relationship of the forward loop is disconnected, so that there is no dependency relationship from the link C2 to the link C3. In other words, for a packet that reaches the node device 301 (2) using the link C2, the node device 301 (2) is always the transmission destination node, and the node device 301 (3) uses the forward loop link C3. Will not be output. Similarly, with respect to the loop in the reverse direction, the dependency relationship between the link C9 and the link C10 does not exist because the loop dependency relationship is disconnected in the node device 301 (3). Therefore, the packet that reaches the node device 301 (3) using the link C9 is always the destination node of the node device 301 (3), and the node device 301 (2) using the link C10 of the reverse loop. Will not be output.
[0099]
FIG. 9 shows which route is selected by the route determination means 105a when the value held in the cut point recording register 102 is 2 in the 6-node bidirectional ring network using the node device 101a according to the present invention. The packet is shown for each source node number and destination node number.
[0100]
Next, a description will be given of the case where the dependency disconnection point is changed during operation in the bidirectional ring network configured using the node device 101a. In the bi-directional ring network according to the present invention, the network management packet from the processing device propagates on a normal loop instead of instructing each node device by a dedicated line to move the dependency cut point. It becomes possible to do it.
[0101]
In the 6-node bidirectional ring network shown in FIG. 3 (using the node device of FIG. 6 according to the present invention as the node device), the disconnection point of the forward loop dependency is changed from the node device 301 (2) to the node device 301 (1 ) Is an example in which the break point of the dependency relationship of the backward loop is changed from the node device 301 (3) to the node device 301 (2). The node devices 301 (0) to 301 (5) are connected in a ring shape by links C1 to C12, and each of the node devices 301 (0) to 301 (5) is connected to a processing device such as a computer. It is omitted in the figure.
[0102]
At the first time point, 2 is recorded in the disconnection point recording register 102 in the node devices 301 (0) to 301 (5), and the dependency relationship of the links in the network is as shown in FIG. At this time, an instruction to move the disconnection point of the dependency relationship is input from the node device 301 (2) to the network as a control special packet.
[0103]
The operation when the control special packet is input to the node device 301 (2) will be described with reference to FIG. The special packet for control is input to the input buffer unit 108 using the input port 114 connected to the processing device. When the input buffer unit 108 determines that the packet is a control special packet, the input buffer unit 108 determines the output destination of the packet. In this case, the output destination of the packet is not set by the route determination unit 105a, but is determined by the input buffer unit 108 so as to move along a loop opposite to the direction in which the dependency cut point moves. In this example, since the cut point of the dependency relationship is moved in the same direction as the backward loop (that is, the direction in which the number unique to the node device is -1), the packet itself goes around the ring along the forward loop. For this purpose, the input buffer unit 108 sends a packet to the output control unit 112 that forms a forward loop. Simultaneously with the transmission of the packet, the input buffer unit 108 updates the content of the cut point recording register 102 from 2 to 1. Thereafter, in the node device 301 (2), it is assumed that the forward loop dependency cut point is in the node device 301 (1), and the reverse loop dependency cut point is in the node device 301 (2). Determine the route as a thing.
[0104]
Next, the operation after the node device 301 (3) receives the control special packet will be described with reference to FIG. The special packet for control is input to the input buffer unit 110 from the input port 116 of the forward loop. Since the buffer in the input buffer unit 110 performs service according to the First In First Out rule, no special processing is performed until the service order of the control special packet is reached. When in service order, this packet is passed to the output control unit 112 along the forward loop. At the same time, the input buffer unit 110 rewrites the contents of the cut point recording register 102 from 2 to 1. Thereafter, in the node device 301 (3), the disconnection point of the forward loop dependency is assumed to be in the node device 301 (1), and the disconnection point of the reverse loop dependency is in the node device 301 (2). Determine the route as a thing.
[0105]
In the node devices 301 (4), 301 (5), and 301 (0), the control special packet is processed in the same manner as the node device 301 (3).
[0106]
Assuming a state immediately after the control special packet is serviced in the node device 301 (4), the dependency relationship of the link in the transient state is shown. At this time, in the node devices 301 (2), 301 (3), and 301 (4), the value of the break point recording register 102 is updated to 1, so that the break point of the forward loop dependency is the node device. It is recognized that the node is in 301 (1), and the disconnection point of the reverse loop dependency is recognized as being in the node device 301 (2). In the node devices 301 (5), 301 (0), and 301 (1), since the value of the cut point recording register 102 is 2, the cut point of the forward loop dependency is the node device 301 (2). And the disconnection point of the dependency relationship of the backward loop is recognized as being in the node device 301 (3).
[0107]
First, focusing on the forward loop, the node device 301 (2), 301 (3), 301 (4) recognizes that the node device 301 (1) is a dependency disconnection point. Depending on the packets transmitted by (2), 301 (3), and 301 (4), a link dependency relationship is formed in the order of C3 → C4 → C5 → C6 → C1. On the other hand, since the node devices 301 (5), 301 (0), 301 (1) recognize that the node device 301 (2) is a dependency cut point, the node devices 301 (5), 301 (0) ), 301 (1) form a dependency relationship such as C6 → C1 → C2. At this time, since there is no dependency relationship of C2 → C3, a cycle is not formed and deadlock cannot occur.
[0108]
Next, paying attention to the loop in the reverse direction, the node device 301 (2), 301 (3), 301 (4) recognizes that the node device 301 (2) is a dependency disconnection point. Link dependencies such as C11.fwdarw.C12.fwdarw.C7.fwdarw.C8.fwdarw.C9.fwdarw.C10 are formed by the packets transmitted by 301 (2), 301 (3), and 301 (4). On the other hand, since the node devices 301 (5), 301 (0), 301 (1) recognize that the node device 301 (3) is a dependency cut point, the node devices 301 (5), 301 (0) ), 301 (1) form a dependency relationship such as C12 → C7 → C8 → C9. At this time, since there is no dependency relationship of C10 → C11, a cycle is not formed and deadlock cannot occur.
[0109]
Therefore, in this bi-directional ring network, no deadlock can occur even when the control special packet circulates the network.
[0110]
Next, the operation after the control special packet reaches the node device 301 (1) will be described with reference to FIG. The special packet for control is input to the input buffer unit 110 from the input port 116 of the forward loop. Since the buffer in the input buffer unit 110 performs service according to the First In First Out rule, no special processing is performed until the service order of the control special packet is reached. When the service order is reached, the input buffer unit 110 updates the contents of the cut point recording register 102 from 2 to 1 in accordance with this packet. At this time, when recognizing that the updated value of the cut point recording register matches its own node device number, the input buffer unit 110 discards the control special packet.
[0111]
As described above, when the control special packet reaches the node (301) along the forward loop from the node device 301 (2), all the node devices 301 (0) to 301 (301) constituting the ring network are obtained. 5), the disconnection point of the dependency relationship of the forward loop is changed from the node device 301 (2) to the node device 301 (1), and the disconnection point of the dependency relationship of the backward loop is changed from the node device 301 (3) to the node device 301 ( 2), the route of the packet in the network is changed. However, when the network adopts wormhole routing, it should be noted that the processing needs to be completed in units of packets when updating the cut point recording register 102 in each node.
[0112]
In the case where the dependency cut point is moved along the forward loop, it can be realized by making the control special packet make a round along the backward loop from the node device 301 (3). In the input buffer unit 113 of the node device, the control special packet compares the updated value of the cut point recording register 102 with its own node number (the value of the node number recording register 104). When moving up, the control special packet itself reaches the issuing node device 301 (3).
[0113]
Next, the claim 8 The invention shown in FIG.
[0114]
In the 6-node bidirectional ring network shown in FIG. In this case, as already described, the dependency between the links between nodes is shown as shown in FIG. 8, and the transmission direction of the packet is determined by the route determining means 105a as shown in FIG. Packets can be sent in any direction when the source node number is 2 or 3. The packet sending direction is determined according to the method shown in FIG. 7, but after the sending direction is determined to be arbitrary,
・ If the sending direction becomes arbitrary in step 702, send to the reverse loop.
-If the transmission direction becomes arbitrary in Steps 704 and 706, if the transmission is set for the forward loop, the link C3 and the link C10, that is, between the node device 301 (2) and the node device 301 (3) are set. The link will not be used at all. After setting the link between node devices 301 (2) and 301 (3) to the unused state by the above settings, it is possible to replace the cables used for the link and add the node. become.
[0115]
【The invention's effect】
As described above, the present invention has the following effects.
[0116]
The first effect is that the packet route in the bidirectional ring network can be easily changed in accordance with the state of the network. The reason for this is that it has route determination means for automatically determining the route of a packet that does not cause a deadlock based on the node number of the node device at the cutting point recorded in the cutting point recording register. This is because the route of the packet can be changed simply by changing the value of the recording register.
[0117]
The second effect is that when the disconnection point of the dependency relationship is changed, the change is made possible by a packet flowing through the normal path of the network, so that a dedicated connection for instructing the change to the node device becomes unnecessary. .
[0118]
The third effect is that the disconnection point of the dependency relationship can be changed while continuing the operation of the network.
[0119]
The fourth effect is that it is possible to provide an environment in which the maintenance and expansion of the network can be easily performed by setting a specific link of the bidirectional ring network to an unused state by changing the disconnection point of the above dependency relationship. is there.
[Brief description of the drawings]
BRIEF DESCRIPTION OF THE DRAWINGS , 2, 9, 10 3 is a block diagram showing a configuration example of a node device 101 according to FIG.
FIG. 2 is a flowchart showing an example of processing performed by route determination means 105 in the node device 101.
FIG. 3 is a block diagram illustrating a configuration example of a 6-node bidirectional ring network.
4 is a diagram showing an example of a directed graph showing a dependency relationship between links when the 6-node bidirectional link network of FIG. 3 is configured using the node device 101. FIG.
5 is a diagram showing an example of routing setting when the 6-node bidirectional link network of FIG. 3 is configured using the node device 101. FIG.
FIG. 6 Claim 3,4,11,12 It is a block diagram which shows the structural example of the node apparatus 101a concerning.
FIG. 7 is a flowchart showing an example of processing performed by route determination means 105a in the node device 101a.
FIG. 8 is a diagram illustrating an example of a directed graph showing a dependency relationship between links when the 6-node bidirectional link network of FIG. 3 is configured using the node device 101a.
FIG. 9 is a diagram illustrating an example of routing setting when the 6-node bidirectional link network of FIG. 3 is configured using the node device 101a.
FIG. 10 is a diagram illustrating an example of deadlock in a unidirectional ring network.
FIG. 11 is a block diagram illustrating a configuration example of a four-node bidirectional ring network according to the related art.
FIG. 12 is a diagram illustrating an example of a directed graph showing a dependency relationship between links in a four-node bidirectional ring network according to a conventional technique.
FIG. 13 is a diagram showing an example of a directed graph showing dependency relationships between links when deadlock avoidance due to routing direction restriction is performed in a four-node bidirectional ring network according to the prior art.
FIG. 14 is a diagram showing an example of routing setting when deadlock avoidance due to routing restriction is performed in a four-node bidirectional ring network according to the prior art.
[Explanation of symbols]
101,101a ... Node device
102 ... Cut point recording register
103 ... Destination recording register
104… Node number recording register
105,105a ... Route decision means
106,107 ... subtractor
108,110,113… Input buffer section
109,111,112… Output control unit
114,116,119… Input port
115,117,118… Output port
301 (0) -301 (5) ... Node equipment
C1-C12 ... link
601 ... Node number recording register
602 ... Adder
1001 (0) to 1001 (3) ... Node device
1002 (0) to 1002 (3) ... Buffers that make up the loop
1003 (0) to 1003 (3) ... Processing equipment
1004 (0) to 1004 (3) ... Buffer that receives input from the processing unit
1005 (0) to 1005 (3) ... packet
1101 (0) to 1101 (3) ... Node device
1102 (0) to 1102 (3) ... Processing equipment
1103 (0) to 1103 (3) ... the buffers that make up the forward loop
1104 (0) to 1104 (3) ... the buffers that make up the reverse loop
1105 (0) to 1105 (3) ... buffer that receives input from the processing unit

Claims (19)

A plurality of node devices are connected in a ring shape by bi-directional links, and different processing devices are connected to the respective node devices, and packets from the processing devices are transmitted and received between the node devices to reach the target processing device. In a bidirectional ring network,
Each node device is given a node number in order along the ring, and
Each of the node devices
An input buffer that holds packets from the processing devices connected to its own node device and services them in the order of arrival;
A rewritable cutting point recording register for recording a node number of a node device as a cutting point for avoiding deadlock;
And about the output destination of the packet held in the input buffer, pre-Symbol a route determination means for determining whether to be sent to either of the bi-directional link, indicated by the value of the breakpoint recorded register When the node device at the disconnection point is the own node device and the node device that is the transmission destination of the packet held in the input buffer, the packet transmission direction is determined to be arbitrary, otherwise Based on the number of hops in a predetermined direction between the own node device and the node device at the disconnection point, and the number of hops in the predetermined direction between the node device to which the packet is transmitted and the node device at the disconnection point Route determining means for determining the packet sending direction,
A bidirectional ring network characterized by comprising: The bidirectional ring network according to claim 1, wherein
Each of the node devices
A first subtractor for subtracting the node number recorded in the cut point recording register from the node number of the own node device and outputting the result as a signed integer;
A second subtracter that subtracts the node number recorded in the cut point recording register from the node number of the node device that is the transmission destination of the packet held in the input buffer, and outputs the result as a signed integer. Have
The route determination means is
If the output of the first subtractor is 0, a first step of determining the packet transmission direction as arbitrary;
If the output of the second subtractor is 0, a second step of determining the packet transmission direction as arbitrary;
Compare the output value of the first subtractor and the output value of the second subtractor as an unsigned integer, and if the former is larger, the packet transmission direction will be the reverse direction where the node number is in descending order When the latter is larger, the bidirectional ring network has a configuration for performing a third step of determining a packet transmission direction as a forward direction in which the node numbers are in ascending order. The bidirectional ring network according to claim 1, wherein
In the cutting point recording register, the node number of the node device to be the cutting point of the forward loop is recorded, and
The route determination means is
If the node device that is the cut point of the forward loop indicated by the value of the cut point recording register is its own node device, it determines that the packet sending direction is arbitrary,
If one node device ahead along the forward loop from the node device at the cut point of the forward loop is its own node device, it determines that the packet transmission direction is arbitrary,
Otherwise, the number of hops in a predetermined direction between the own node device and the node device at the cut-off point of the forward loop, the node device that is the packet transmission destination, and the node device at the cut-off point of the forward loop A bidirectional ring network having a configuration for determining a packet transmission direction based on the number of hops in a predetermined direction between the two. The bidirectional ring network according to claim 1, wherein
In the cutting point recording register, the node number of the node device as the cutting point of the forward loop is recorded,
Each of the node devices
A first subtractor for subtracting the node number recorded in the cut point recording register from the node number of the own node device and outputting the result as a signed integer;
A second subtracter that subtracts the node number recorded in the cut point recording register from the node number of the node device that is the transmission destination of the packet held in the input buffer, and outputs the result as a signed integer. Have
The route determination means is
If the output of the first subtractor is 0, a first step of determining the packet transmission direction as arbitrary;
If the output of the first subtractor is 1, the second step of determining the packet transmission direction as arbitrary;
When the value of the cut point recording register is 0 and the node number unique to the own node device is the maximum value in the bidirectional ring network, a third step of determining the packet transmission direction as arbitrary;
If the output of the second subtractor is 0, a fourth step of determining the packet sending direction as a forward direction in which the node numbers are in ascending order;
Compare the output value of the first subtractor and the output value of the second subtractor as an unsigned integer, and if the former is larger, the packet sending direction is in the reverse direction in which the node numbers are in descending order, A bidirectional ring network characterized in that, if the latter is larger, a fifth step of determining a packet transmission direction in a forward direction in which node numbers are in ascending order is performed. A plurality of node devices are connected in a ring shape by bi-directional links, and different processing devices are connected to the respective node devices, and packets from the processing devices are transmitted and received between the node devices to reach the target processing device. In a bidirectional ring network,
Each node device is given a node number in order along the ring, and
Each of the node devices
An input buffer that holds packets from the processing devices connected to its own node device and services them in the order of arrival;
A rewritable cutting point recording register for recording a node number of a node device as a cutting point for avoiding deadlock;
Route determination means for determining which of the two-way links should be sent from the value of the cut point recording register regarding the output destination of the packet held in the input buffer;
When a control special packet instructing to change the node number recorded in the cut point recording register arrives from a processing device connected to the own node device or an adjacent node device, the control special packet precedes the control special packet. A bidirectional ring network comprising: a configuration in which a value of a cut point recording register in the own node device is updated in accordance with an instruction of the special packet for control after processing of a packet to be performed is completed . The bidirectional ring network according to claim 5 , wherein
Each of the node devices
A special packet for control instructing to change the node number recorded in the cut point recording register, which arrives from the processing device connected to the own node device, is sent to one of the adjacent node devices. A bidirectional ring network characterized by having a configuration and sending a control special packet arriving from one adjacent node device to the other adjacent node device. The bidirectional ring network according to claim 6 , wherein
Each of the node devices
When a special packet for control arrives from a processing device connected to its own node device, a bi-directional ring network at the cut point based on the content of the special packet for control and the node device at the current forward loop cut point One of the adjacent node devices for judging the control special packet so that the direction in which the control special packet flows is opposite to the direction of movement of the cutting point. A bidirectional ring network characterized by having a configuration for sending to a node device. The bidirectional ring network according to claim 4 , wherein
The route determination means is
If the sending direction is determined to be arbitrary in the first step, the sending direction of the packet is determined to be the direction in which the node number is descending, and if the sending direction is determined to be arbitrary in the second or third step Is a bidirectional ring network characterized by having a configuration for determining a packet transmission direction in a direction in which node numbers are in ascending order. An input buffer that holds packets from the processing devices connected to the node device and services them in the order of arrival;
A rewritable cutting point recording register for recording a node number of a node device as a cutting point for avoiding deadlock;
Aforementioned about the output destination of the packet held in the input buffer, a route determining means for determining whether to be sent to either of the bidirectional link connected to the own node device, the cutting point recording If the node device at the disconnection point indicated by the value of the register is its own node device, and if it is the node device that is the transmission destination of the packet held in the input buffer, the packet transmission direction is determined as arbitrary, In other cases, the number of hops in a predetermined direction between the own node device and the node device at the disconnection point, and the predetermined direction between the node device that is the transmission destination of the packet and the node device at the disconnection point. Route determining means for determining the packet transmission direction based on the number of hops ;
A node device comprising: The node device according to claim 9 , wherein
A first subtractor for subtracting the node number recorded in the cut point recording register from the node number of the own node device and outputting the result as a signed integer;
A second subtracter that subtracts the node number recorded in the cut point recording register from the node number of the node device that is the transmission destination of the packet held in the input buffer, and outputs the result as a signed integer. Have and
The route determination means is
If the output of the first subtractor is 0, a first step of determining the packet transmission direction as arbitrary;
If the output of the second subtractor is 0, a second step of determining the packet transmission direction as arbitrary;
Compare the output value of the first subtractor and the output value of the second subtractor as an unsigned integer, and if the former is larger, the packet transmission direction will be the reverse direction where the node number is in descending order A node device characterized by comprising a third step of determining, in the latter case, the packet transmission direction as a forward direction in which the node numbers are in ascending order. The node device according to claim 9 , wherein
In the cutting point recording register, the node number of the node device to be the cutting point of the forward loop is recorded,
The route determination means is
When the node device that is the cut point of the forward loop indicated by the value of the cut point recording register is its own node device, it determines that the packet sending direction is arbitrary,
If the node device that is one node ahead along the forward loop from the node device at the cut-off point of the forward loop is the own node device, the packet transmission direction is determined as arbitrary,
In other cases, the number of hops in a predetermined direction between the own node device and the node device at the cut-off point of the forward loop, the node device that is the transmission destination of the packet, and the node device at the cut-off point of the forward loop A node device having a configuration for determining a packet transmission direction based on the number of hops in a predetermined direction between the first node and the second node. The node device according to claim 9 , wherein
In the cutting point recording register, the node number of the node device as the cutting point of the forward loop is recorded, and
A first subtractor for subtracting the node number recorded in the cut point recording register from the node number of the own node device and outputting the result as a signed integer;
A second subtracter that subtracts the node number recorded in the cut point recording register from the node number of the node device that is the transmission destination of the packet held in the input buffer, and outputs the result as a signed integer. Have and
The route determination means is
If the output of the first subtractor is 0, a first step of determining the packet transmission direction as arbitrary;
If the output of the first subtractor is 1, the second step of determining the packet transmission direction as arbitrary;
When the value of the cut point recording register is 0 and the node number unique to the own node device is the maximum value in the bidirectional ring network, a third step of determining the packet transmission direction as arbitrary;
If the output of the second subtractor is 0, a fourth step of determining the packet sending direction as a forward direction in which the node numbers are in ascending order;
Compare the output value of the first subtractor and the output value of the second subtractor as an unsigned integer, and if the former is larger, the packet sending direction is in the reverse direction in which the node number is in descending order, And a fifth step of determining a packet transmission direction in a forward direction in which the node numbers are in ascending order when the latter is larger. An input buffer that holds packets from the processing devices connected to the node device and services them in the order of arrival;
A rewritable cutting point recording register for recording a node number of a node device as a cutting point for avoiding deadlock;
Route determining means for determining which of the two-way links connected to the own node device should be sent from the value of the cut point recording register with respect to the output destination of the packet held in the input buffer; ,
A special packet for control instructing to change the node number recorded in the disconnection point recording register arrives from a processing device connected to the own node device or an adjacent node device connected to the own node device by a bidirectional link In this case, the node has a configuration in which after the processing of the packet preceding the control special packet is completed , the value of the disconnection point recording register in the own node device is updated according to the instruction of the control special packet. apparatus. The node device according to claim 13 , wherein
A configuration in which a special packet for control instructing the change of the node number recorded in the cut point recording register, which arrives from the processing device connected to the own node device, is sent to one of the adjacent node devices. And having a configuration for sending a control special packet arriving from one adjacent node device to the other adjacent node device. The node device according to claim 14 , wherein
When a control special packet arrives from a processing device connected to the own node device, the movement direction of the cut point on the bidirectional ring network based on the content of the control special packet and the content of the cut point recording register And transmitting the control special packet to one of the adjacent node devices so that the direction in which the control special packet flows is opposite to the moving direction of the cutting point. A node device comprising: The node device according to claim 12 , wherein
The route determination means is
If the sending direction is determined to be arbitrary in the first step, the sending direction of the packet is determined as the reverse direction in which the node number is descending, and the sending direction is determined to be arbitrary in the second or third step. In this case, the node apparatus has a configuration in which the packet transmission direction is determined to be a forward direction in which the node numbers are in ascending order. A plurality of node devices are connected in a ring shape by bi-directional links, and different processing devices are connected to the respective node devices, and packets from the processing devices are transmitted and received between the node devices to reach the target processing device. A bi-directional ring network,
Each node device is given a node number in order along the ring, and
Each of the node devices
An input buffer that holds packets from the processing devices connected to its own node device and services them in the order of arrival;
A rewritable cutting point recording register for recording a node number of a node device as a cutting point for avoiding deadlock;
Route determination means for determining which of the two-way links should be sent from the value of the cut point recording register regarding the output destination of the packet held in the input buffer;
A bi-directional ring network control method for controlling a bidirectional ring network with,
When the control for the special packet instructing a change of the node number stored in the adjacent node device or al switching Danten recording register to form a processing apparatus or the ring is connected to the node device has arrived, the A bidirectional ring network control method, characterized in that a value of a cut point recording register in the own node device is updated by the control special packet after processing of a packet preceding the control special packet is completed . The bidirectional ring network control method according to claim 17 ,
A special packet for control arriving from the processing device is
Update the value of the breakpoint recording register in the node device connected to the processing device,
Furthermore, by making a round while updating the contents of the cutting point recording register of each node device on the ring network,
A bidirectional ring network control method, characterized by moving a cut point of a dependency relationship to avoid a deadlock on a bidirectional ring network. The bidirectional ring network control method according to claim 18 , wherein
The control special packet is:
A bidirectional ring network control method comprising: making a round on a ring network in a direction opposite to a direction in which a cut point of a dependency relationship for avoiding deadlock is moved on the bidirectional ring network.

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