JP3970448B2 - Information relay method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to information relay technology, and in particular, is used in a router device or the like that relays a packet in a computer network system to determine a relay destination to which the packet is to be transmitted next from the destination address of the received packet. The present invention relates to a technology effective when applied to a route information table creation technology and the like.
[0002]
[Prior art]
In response to advances in computer technology and information network technology, computer networks in which a plurality of computers are connected via an information network, as represented by the so-called Internet, have become widespread. In addition, as data sent and received within this computer network, there is an increasing amount of data that is important for real-time performance, such as so-called multimedia data such as video and audio, and relays data within the computer network. Information relay apparatuses such as router apparatuses are also required to increase the speed of the relay operation at the same communication speed as the communication medium itself.
[0003]
The information relay technology that is the reference technology of the present invention will be described below with reference to FIG. The router device of the reference technology holds a route search unit F100, a control route search unit F200, and an additional mechanism unit F300.
[0004]
The route search unit F100 holds a route search table TBL100 for registering a route information entry E having an address of a device to be transmitted next and line information to which the device is connected. The route information entry E includes a subnetwork address and a mask length, line information, a next hop address, and information on whether or not the subnetwork is directly connected (hereinafter referred to as next hop information). The route search unit F100 adds or deletes a route information entry E set by a user or obtained by exchanging connection information between router devices by a routing protocol or the like to the route search table TBL100. Further, when a packet is received, the route search unit F100 compares the pair of the subnetwork address and the mask length of the route information entry E in the route search table TBL100 with the search key and compares it with the destination address of the packet. Search for existence.
[0005]
The control route search unit F200 holds a control route table TBL200 that registers control route information entries CE other than the route information necessary for packet relay. The control path information entry CE is composed of a control path address to be transferred to the additional mechanism unit. The control route search unit F200 performs search processing of the packet received by the route search unit F100, and then compares the control route address of the control route information entry CE of the control route search table TBL200 with the destination address of the packet, and matches the control route A search is made to see if an information entry CE exists. If there is a matching control path information entry CE, the packet is transferred to the additional mechanism unit F300. If there is no matching control route information entry CE, the packet is transmitted according to the search result of the route search unit F100.
[0006]
There is a Radish algorithm with a binary tree structure as a route search method according to the above search specifications. The Radish algorithm maps a path entry to each node of a tree structure composed of a tree in which a plurality of vertices (nodes) having pointers on the left and right are connected by pointers. The target route entry arrives at the node to which the target route entry is mapped by following the pointer and moving to the next node.
[0007]
First, the structure of the tree will be described with reference to FIG. Since the concept does not depend on the bit length, in FIG. 23, the address length is assumed to be 3 bits for easy understanding.
[0008]
As shown in FIG. 23, each node is called a node having a mask length of 0 bit, 1 bit, 2 bits, and 3 bits in order from the top of the tree.
[0009]
The node N0000 having a mask length of 0 bit moves to the nodes N0001 and N1001 having a mask length of 1 bit by following the left / right pointer according to whether the 0th bit of the destination address is 0 or 1, and the node having the mask length of 1 bit has the first address. By following the left / right pointer according to whether the bit is 0 or 1, the node moves to the nodes N0002, N0102, N1002, and N1102 having the mask length of 2 bits. In the node having the mask length of 2 bits, the left / right is determined according to whether the second bit is 0 or 1. By following the pointer on the right, the process moves to nodes N0003, N0013, N0103, N0113, N1003, N1013, N1103, and N1113 having a mask length of 3 bits.
[0010]
When the pointer is traced according to whether each bit is 0 or 1 in order from the node N0000 having a mask length of 0 bits for the destination address to be searched, the node having the mask length of 0 bit passes through any destination address. Nodes N0001 and N1001 having a mask length of 1 bit pass when the bits of the destination address are 0XX and 1XX in order from the left, and nodes N0002, N0102, N1002, and N1102 having a mask length of 2 bits are the bits of the destination address in order from the left. Is passed through when the address is 00X, 01X, 10X, 11X, and the nodes N0003, N0013, N0103, N0113, N1003, N1013, N1103, and N1113 having mask lengths of 3 bits are 000,001,010 each bit of the destination address in order from the left. , 011,100,101,110,1 Passing in the case of 1. Here, X indicates that the bit value may be either 0 or 1.
[0011]
Therefore, the node N0000 having a mask length of 0 bit passes when the destination address belongs to the subnetwork address 000/0, and the nodes N0001 and N1001 having the mask length of 1 bit pass through the subnetwork address 000 / 1,100 / The node N0002, N0102, N1002, and N1102 having a mask length of 2 bits pass when the destination address belongs to the subnetwork address 000/2, 010/2, 100/2, and 110/2. , Nodes N0003, N0013, N0103, N0113, N1003, N1013, N1103, and N1113 having a mask length of 3 bits have sub-network addresses 000/3, 001/3,. . . , 111/3. Here, in the notation “sss / m”, “sss” represents a subnetwork address, and m represents a mask length.
[0012]
As described above, each node of this tree has a one-to-one correspondence with all subnets having different subnetwork addresses and mask lengths.
[0013]
Therefore, “*” is added to the nodes N0000, N0013, N0102, N1001, and N1103 corresponding to the path information entry shown in FIG. 24, and the destination address DA011 to be searched is a pointer according to whether each bit is 0 or 1 from the top of this tree. It can be seen that the nodes N0000 and N0102 to which “*” that passes when the path is traced correspond to the matching entries in the search with a mask. Therefore, this corresponds to the rule that when a plurality of path information entries match, the sub-network with the longest mask length is selected, and among the matching nodes N0000 and N0102 with “*”, it is assigned to the node N0102 closest to the end. The route information obtained is used as a route table search result.
[0014]
As can be seen from the above search method, the nodes N0003, N0103, N0113, N1003, N1013, N1113, and N1002 that do not have “*” and are not on the way to reach the node with “*” Removing it from the tree does not affect the search results. Rather, when the “*” is not attached to the lowest node, the search is completed without moving to the lowest node, which is efficient. Therefore, when a node that is not marked with “*” and is not a halfway route to reach a node marked with “*” is removed from the tree as shown in FIG.
[0015]
Further, the nodes N0002 and N1102 to which the next node is connected to only one of the left and right pointers and the route information is not mapped are removed from the tree, and nodes N0013 and N1103 are added immediately below N0001 and N1001, respectively. As a result, the shape shown in FIG. 26 is obtained. This removal of the intermediate node sequence is hereinafter referred to as tree degeneration.
[0016]
A method for adding / deleting a route information entry to / from the route management table having a binary tree structure will be described.
[0017]
FIG. 27 shows an example of adding route information to a binary tree. FIG. 27A shows a route management table before entry addition, and FIG. 27B shows a route management table after entry addition. A method for adding a route information entry and a control route information entry to a route management table having a binary tree structure will be described with reference to FIG. In order to determine the addition position of the node generated by adding an entry, the search is performed from the first node downward to the lower node, and the sub-network of the node to be searched (hereinafter referred to as the current node) and the entry to be added The address and mask length are compared, and a current node that meets the four determination conditions is detected. Four determination conditions are shown below.
[0018]
(A-1) When the sub-network address of the current node matches the mask length.
[0019]
(A-2) When the current node does not match the subnetwork address.
[0020]
(A-3) When the mask length is larger than the mask length of the current node, matches the subnetwork address of the current node, and the pointer in the child node direction to be searched next is NULL.
[0021]
(A-4) When the mask length is smaller than the mask length of the current node and the subnetwork addresses match.
[0022]
However, the comparison of the network address is performed by the mask length of the smaller one of the current node and the additional node. Examples that apply to each of the four determination conditions are shown below.
[0023]
When the subnetwork address and mask length of the entry to be added are 133.5.16.0/21, the determination condition (A-1) is satisfied. In FIG. 27A, the current node is moved in the order of the nodes S1, S2, S4, and S5, and the determination condition (A-1) is satisfied in the node S5. When the determination condition (A-1) is satisfied, the route information node to be added is a branch node as shown in FIG. 27B, so the route information is written in the entry of the branch node S5 and changed to the route information node S5. .
[0024]
When the subnetwork address and mask length of the entry to be added are 133.5.19.0/24, the determination condition (A-2) is satisfied. In FIG. 27A, the current node is moved in the order of the nodes S1, S2, S4, S5, and S6, and the determination condition (A-2) is satisfied in the node S6. When the determination condition (A-2) is satisfied, a route information node SA1 is added as shown in FIG. 27B, and a branch node SA2 is added because there is no parent node that branches the current node S6 and the route information node SA1. Then, the pointer in the direction of the left child node of the node S5 that has become the parent node of the branch node SA2 is changed from the node S6 to the node SA2.
[0025]
When the subnetwork address and mask length of the entry to be added are 133.4.1.0/24, the determination condition (A-3) is satisfied. In FIG. 27A, the current node is moved from the node S1 → S2 → S3, and the determination condition (A-3) is satisfied at the node S3. When the determination condition (A-3) is satisfied, a route information node SA3 is added as shown in FIG. 27B, and the pointer in the left child node direction of S3 corresponding to the parent node of the route information node SA3 is route information from NULL. Change to node SA3.
[0026]
When the subnetwork address and mask length of the entry to be added are 133.5.22.0/23, the determination condition (A-4) is satisfied. In FIG. 27A, the current node is moved in the order of the nodes S1, S2, S4, S5, and S7, and the determination condition (A-4) is satisfied in the node S7. When the determination condition (A-4) is satisfied, a route information node SA4 is added as shown in FIG. 27B, and a pointer in the direction of the left child node of the node S5 corresponding to the parent node of the route information node SA4 is set from the node S7. Change to the route information node SA4.
[0027]
FIG. 28 shows an example of route information deletion to the binary tree. FIG. 28A shows a path management table before entry deletion, and FIG. 28B shows a path management table after entry deletion. A method of deleting the route information entry and the control route information entry from the route management table having a binary tree structure will be described with reference to FIG. In order to determine the deletion position of the node generated by deleting the entry, the search is performed from the first node downward to the current node (hereinafter referred to as the deletion target node) where the subnetwork address of the entry to be deleted matches the mask length. ) Is detected. The current node applies to one of the following four determination conditions.
[0028]
(D-1) When the node to be deleted has two child nodes.
[0029]
(D-2) When the node to be deleted does not have a child node and the parent node does not have route information (except for the first node).
[0030]
(D-3) When the deletion target node does not have a child node and the parent node has path information.
[0031]
(D-4) When the deletion target node has one child node.
[0032]
Examples that apply to each of the four determination conditions are shown below.
[0033]
When the subnetwork address and the mask length of the entry to be deleted are 133.55.16.0/21, the determination condition (D-1) is satisfied. In FIG. 28A, the current node is moved in the order of the nodes S1, S2, S4, and S5, and the determination condition (D-1) is satisfied in the node S5. When the determination condition (D-1) is satisfied, the route information node S5 to be deleted is also a branch node as shown in FIG. 28B, so the route information of the entry of the node S5 is deleted and changed to the branch node S5. .
[0034]
When the subnetwork address and the mask length of the entry to be deleted are 133.5.19.0/24, the determination condition (D-2) is satisfied. In FIG. 28A, the current node is moved in the order of the nodes S1, S2, S4, S5, SD2, and SD1, and the determination condition (D-2) is satisfied at the node SD1. When the determination condition (D-2) is satisfied, as shown in FIG. 28 (b), the pointer in the direction of the left child node of the node S5 corresponding to the parent node of the branch node SD2 corresponding to the parent node of the deletion target node SD1 and the node S6 is set as the node. Change from SD2 to node S6. Subsequently, the branch node SD2 is deleted, and the deletion target node SD1 is deleted.
[0035]
When the subnetwork address and the mask length of the entry to be deleted are 133.4.1.0/24, the determination condition (D-3) is satisfied. In FIG. 28A, the current node is moved in the order of the nodes S1, S2, S3, and SD3, and the determination condition (D-3) is satisfied at the node SD3. When the determination condition (D-3) is satisfied, the deletion target node SD3 is a terminal node as shown in FIG. 28B, and therefore the pointer in the left child node direction of the node S3 corresponding to the parent node of the deletion target node SD3 is deleted. The target node SD3 is changed to NULL, and the deletion target node SD3 is deleted.
[0036]
When the subnetwork address and mask length of the entry to be deleted are 133.5.22.0/23, the determination condition (D-4) is satisfied. In FIG. 28A, the current node is moved in the order of the nodes S1, S2, S4, S5, and SD4, and the determination condition (D-4) is satisfied at the node SD4. When the determination condition (D-4) is satisfied, as shown in FIG. 28B, the pointer in the left child node direction of the node S5 corresponding to the parent node of the deletion target node SD4 is changed from the deletion target node SD4 to the child node of the deletion target node. Update to S7 and delete the deletion target node SD4.
[0037]
As a method for further speeding up the Radish algorithm based on the binary tree structure, there is a “network next transfer destination high-speed search technology” described below. As shown in FIG. 29, the route search table of the “network next transfer destination high-speed search technology” has a 2 p-th power tree structure that holds 2 m powers of the first-stage nodes having a mask length of m bits. The Radish algorithm based on the binary tree structure of the reference technique searches the search bit by bit from the upper bits of the destination address, whereas the “next transfer destination high-speed search technique of the network” in FIG. By making the minutes one p-th power tree and performing the p-stage of the binary tree in one search, the search processing time is shortened to 1 / p and the search processing speed is increased. In addition, the “next transfer destination high-speed search technology of the network” expands the first-stage node having a mask length of m bits to 2 m to a predetermined position on the storage unit, and each of the nodes having a mask length of m bits is A path having a mask length of m bits, corresponding to values that can be taken from the 0th bit to the (m−1) th bit of the destination address, and according to the value of the 0th bit to the (m−1) th bit of the destination address of the received packet By selecting one of the information entries, the search time for the first m bits is eliminated to speed up the search process.
[0038]
[Problems to be solved by the invention]
As in the above-described reference technique, when a 2 p-th power tree structure that holds 2 m first-stage nodes having a mask length of m bits is employed as the route search table, the search process can be speeded up. However, when the route search table is dynamically updated in accordance with a change in the configuration of the computer network, the update process and the search process need to be executed on the same two p-th tree structure. There is a concern that the route search is stopped during the processing, and the search speed decreases.
[0039]
When adding, deleting, or changing 2 p-th power tree nodes in the route search table for each entry, search is performed while the node to be added, deleted, or changed is separated from the tree structure. Doing so raises concerns about erroneous searches, and it is also necessary to stop route searches.
[0040]
Furthermore, in the reference technology, special packets such as broadcasts are registered and processed in a search table different from normal packets, so that the work of expanding the function of a computer network and search processing become complicated. There are also some challenges.
[0041]
An object of the present invention is to provide an information relay technology that can dynamically convert a Radish Tree having a binary tree structure into a p-th tree structure of 2 and increase the speed.
[0042]
An object of the present invention is to provide an information relay technique capable of shortening a route search stop time associated with the update of route control information and realizing a high speed relay control.
[0043]
Another object of the present invention is to shorten the dynamic update of the 2 p-th power tree structure in a shorter time when converting a Radish Tree having a binary tree structure to a p-th power tree structure of 2 to increase the speed. It is an object of the present invention to provide an information relay technology that can be accurately performed within a route search stop time.
[0044]
It is another object of the present invention to add, delete, and change 2 p-th power tree nodes of a route search table for each entry, without separating the nodes necessary for route search from the tree structure. An object of the present invention is to provide an information relay technique capable of minimizing the search interruption time by performing addition and deletion.
[0045]
Another object of the present invention is to provide an information relay technique capable of easily expanding the function of a computer network by adding control route information assigned to a special function of the computer network to a route search table. There is to do.
[0046]
[Means for Solving the Problems]
In the present invention, in an information relay device such as a router device, the route search unit is separated into a route search unit that searches for a transfer destination of a received packet and a route management unit that adds and deletes route information entries. The route management unit holds a route management table having a binary tree configuration for generating a route search table having a 2 p-th tree configuration held by the route search unit. Each 2 p-th power tree node in the route search table holds only information on child nodes necessary for route search, and the binary tree node in the route management table holds information on parent nodes and child nodes. Based on the parent node and child node information, the path management unit adds, deletes, and changes a binary tree from the parent-child relationship between the binary tree nodes of the path management table when the path information is added or deleted. The position of the node is determined and the binary tree structure is updated. Next, the position of the 2 pth power tree node including the binary tree node is determined from the subnetwork address of the binary tree node and the mask length. Next, the path information of the node in the child node direction is given priority over the path information of the node in the parent node direction by the parent node and child node information held by the binary tree node existing in the 2 p power tree node. When the node in the child node direction does not have the route information and the node in the parent node direction has the route information, the route information of the 2 p-th tree node is set by inheriting the route information. Next, addition, deletion, and change of the 2 p-th power tree are determined from the number of binary tree nodes existing in the 2 p power tree node. When the number is changed from 0 to 1, a new p-th power tree node is added. When the number is changed from 0 to 1, the p-th power tree node is deleted. Change the p-th power tree node.
[0047]
In the control mechanism in which the first stage nodes having 2 m mask lengths of m bits have a one-to-one correspondence with the values that can be taken from the 0th bit to the (m-1) th bit of the address, When adding route information up to (m-1) bits, a search is made for a plurality of first-stage nodes whose path information addresses match the value obtained by masking the address of the first-stage node with the mask length of the route information. Set the route information to be added when the selected node has no route information. When deleting the route information from the mask length 0 bit to (m−1) bits, the first node is updated by deleting the route information of the first node having the route information.
[0048]
In addition, when a node is added between nodes in a parent-child relationship for adding one path information in a control mechanism that adds, deletes, and changes 2 p-th power tree nodes of the path search table for each entry, After the addition target node and the child node are connected, the parent node and the addition target node are connected. When deleting a node having a parent and a child for deleting one path information, the deletion target node is deleted after connecting the parent node of the deletion target node with the child node of the deletion target node. This node addition / deletion method realizes node addition / deletion without separating nodes necessary for route search from the tree structure.
[0049]
When additional functions are added to the route management function and route search function, an additional mechanism is newly added, control route information other than route information necessary for packet relay is additionally registered in the route search table, and the destination address of the received packet When is matched with the control route information, the packet is transferred from the route search function to the additional mechanism to realize the additional function.
[0050]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0051]
FIG. 1 is a functional block diagram showing an example of the configuration of a router device that is an embodiment of an information relay device that implements the information relay method of the present invention.
[0052]
The configuration of the router device according to the present embodiment will be described. The router device of the present embodiment includes a route management unit F0, a route search unit F1, and an additional mechanism unit F3. The route management unit F0 obtains a route information entry E having an address of another router device to be transmitted next and line information to which the router device is connected, and a control route information entry CE other than the route information necessary for packet relay. The route management table TBL0 to be registered is held. The route management table TBL0 stores route information in a binary tree structure, and has a degenerated configuration leaving a node having the route information and a node where the branch occurs, and the node holds the route information and the parent node and child node information. To do.
[0053]
The route search unit F1 holds a route search table TBL1 that reflects the route information and control route information of the route management table TBL0. The route search table TBL1 stores route information in a 2-p power tree structure in which p-stages of binary tree nodes are combined into one, and is a degenerated structure that leaves a node having route information and a node where a branch occurs. The node holds path information and child node information.
[0054]
FIG. 2 shows an example of the configuration of the binary tree node of the path management table TBL0. In the case of the present embodiment, each binary tree node 100 in the path management table TBL0 includes a pointer 101 to an upper parent node, a pointer 102 to a child node indicating two lower child nodes, and a child node. A pointer 103, a flag 104 indicating whether or not the child node has path information, a flag 105, a mask length 106 and a mask length 107 of the child node, and a subnetwork address 108 set in the node, It has information such as a next hop address 109 as route information, an output port number 110 that identifies one of the plurality of ports 50, and the like.
[0055]
FIG. 3 shows an example of the configuration of 2 p-th tree nodes in the route search table TBL1. In the case of the present embodiment, each 2 p-th power tree node 200 in the route search table TBL1 indicates a pointer 201 to 2 p power child nodes, and whether or not route information is set in each child node. 2 p-th power flag 202, mask length 203 of the child node, subnetwork address 204 set for the node, next hop address 205 as route information, and output for specifying one of the plurality of ports 50 It has information such as port number 206.
[0056]
Next, an example of the function of the router device according to the present embodiment will be described. The route management unit F0 adds and deletes the route information entry E and the control route information entry CE to the route information table including the route management table TBL0 and the route search table TBL1. In order to store the entry in the binary tree structure in the path management table TBL0, the path management unit F0 determines the position of the node to be added, deleted, or changed from the parent node and child node information of the node and updates the binary tree. The route management unit F0 updates the route search table TBL1 based on the updated route management table TBL0. In the case of adding an entry, the position of the 2 p power tree node including the added or changed binary tree node is determined, and the 2 p power tree node calculated in the route search table TBL1 is added or changed. In the case of entry deletion, the position of the 2 p power tree node including the deleted or changed binary tree node is determined, and the 2 p power tree node calculated in the route search table TBL1 is deleted or changed.
[0057]
When the packet search unit F1 receives the packet 51 from one of the plurality of ports 50, the route search unit F1 receives the sub-network address of the route information entry E and the control route information entry CE registered in the route search table TBL1. And the destination address is searched from the p-th tree node of the first stage 2 of the path search table TBL1 in the downward direction based on the child node information possessed by the node. Among the matching entries, the entry with the longest mask length is taken as the search result. When the search result is the route information entry E, the packet 51 is transmitted from one port 50 corresponding to the output port number among the plurality of ports 50 according to the output port number and next hop address information of the entry. When the search result is the control route information entry CE, the packet 51 is transferred to the additional mechanism unit F3. When receiving the packet 51, the adding mechanism unit F3 processes the packet 51 in accordance with the contents of the packet 51.
[0058]
The operation of the route management unit triggered by the addition or reduction of route information will be described below with reference to the flowchart of FIG.
[0059]
When the addition or deletion of the route information occurs, as described in the reference technique after FIG. 22 above, the binary tree node of the route information table is updated (step FC0 in FIG. 4).
[0060]
Next, it is determined whether or not the mask length of the path information to be added or deleted is greater than or equal to m (step FC1 in FIG. 4). If it is greater than or equal to m (step FC9 in FIG. 4), 2 including the updated binary tree node 2 A method for updating the path information of the p-th power tree node (step FC2 in FIG. 4) will be described. FIG. 5 shows an example of converting a binary tree for four stages into a sixteen tree. FIG. 5A shows binary tree nodes for four stages. In the binary tree, there are nodes with route information and nodes without route information. FIG. 5B shows a 16-tree node in which 4 levels of binary trees are combined into one. The 16-tree node is sized only at the fourth level of the binary tree node. In order to set the path information of a binary tree node by a 16-tree node, it is performed in accordance with a path search specification in which a path information entry having a long mask length is adopted when a plurality of path information entries having different mask lengths match. . Based on this specification, there are two rules for setting path information using parent node and child node information held by a binary tree node existing in a 16-tree node. The first is to prioritize the route information of the node in the child node direction over the route information of the node in the parent node direction. The second is the direction of the parent node when the node in the child node direction has no route information. When the node has route information, it inherits the route information (specifically, it is overwritten with the information of the destination to which the next hop address 205 and the output port number 206 are inherited). When the binary tree in FIG. 5A is converted into a 16-tree tree according to this rule, FIG. 5B is obtained.
[0061]
Next, a method of setting route information when route information is added will be described with reference to FIG. FIG. 6 shows an example in which route information is added from the state of FIG. In the case of adding route information, the child node information is required to check whether the route information exists in the node in the child node direction. Therefore, the binary tree node 100 of the path management table TBL0 holds child node information (pointers 102 and 103 to the child nodes in FIG. 2). When the child node A001 of the node A00 to which the route information is added has route information, A001 of the 16-tree node in FIG. 6B gives priority to the route information of * A001. When the child node A110 of the node A11 to which the route information is added does not have the route information, the route information of * A11 is set in A110 of the 16-tree node in FIG. 6B.
[0062]
Next, a method of setting route information when route information is deleted will be described with reference to FIG. FIG. 7 shows an example in which the route information is deleted from the state of FIG. In the case of deletion of route information, information on the parent node is required to check whether the route information exists in the node in the parent node direction. Therefore, the binary tree node 100 of the path management table holds parent node information (a pointer 101 to the parent node in FIG. 2). When the node A100 in the child node direction of the node A1 from which the route information is deleted has route information, the A100 of the 16-tree node in FIG. 7B gives priority to the route information of * A100 as it is. When the parent node A01 of the node A010 from which the route information is deleted has the route information, the route information of * A01 is set in A010 of the 16-tree node in FIG. 7B.
[0063]
Next, by changing the number of binary tree nodes existing in the 2 p-th power tree node 200 (step FC4 in FIG. 4), one of the addition, deletion and change of the 2 p-th power tree nodes is changed. A method of selecting will be described.
[0064]
The addition and deletion of 2 p-th power tree nodes will be described. The route management unit F0 adds, deletes, or changes the 2 p-th tree node 200 excluding the first stage of the route search table TBL1 by adding or deleting route information entries. The addition, deletion, and change of 2 p-th power tree nodes are determined by the number of binary tree nodes included in the updated 2 p power tree nodes. Four patterns generated by adding and deleting route information entries will be described with reference to FIG.
[0065]
FIG. 8A shows a case where there is no node other than the binary tree node SA1 in the 2 p-th power tree node LA1 including the added binary tree node SA1 (step FC11 in FIG. 4). In this case, a new p-th power tree node LA1 is created and added to the route search table TBL1 (step FC5 in FIG. 4).
[0066]
FIG. 8B shows a case where there is a node S1 other than the binary tree node SA1 in the 2 p-th power tree node L1 including the added binary tree node SA1 (step FC13 in FIG. 4). In this case, since the 2 p-th power tree node L1 already exists, route information is assigned to the 2 p-th power tree node L1, and the 2 p-th power tree node L1 of the route search table TBL1 is changed. (Step FC7 in FIG. 4).
[0067]
FIG. 8C shows a case where there is no binary tree node in the 2 p-th power tree node LD1 including the deleted binary tree node SD1 (step FC12 in FIG. 4). In this case, since the 2 p-th power tree node LD1 no longer has a binary tree node, the 2 p-th power tree node LD1 in the path search table TBL1 is deleted (step FC6 in FIG. 4).
[0068]
FIG. 8D shows a case where a binary tree node exists in the 2 p-th power tree node L1 including the deleted binary tree node SD1 (step FC13 in FIG. 4). In this case, since the 2 p power tree node L1 has a binary tree node, the 2 p power tree node L1 of the path search table TBL1 is changed (step FC7 in FIG. 4).
[0069]
Next, a method of updating the 2 p-th tree of the route search table TBL1 (step FC8 in FIG. 4) will be described.
[0070]
First, a method for adding the route information entry E to the route search table TBL1 having a 2 p power tree structure will be described. In the above description of the reference technique, it has been explained that when an entry is added to the binary tree structure, the binary tree node is updated with four additional patterns. In order to reflect the update on the p-th power tree of 2 Needs to update one or more 2 p-th tree nodes. Therefore, the router device according to the present embodiment, which adds, deletes, and changes 2 p-th power tree nodes one by one with respect to the route search table TBL1, does not need to be updated when adding route information. Among them, by updating in order from the parent node to the child node, it is possible to perform a route search process between node updates.
[0071]
Using FIG. 9, a method of adding 2 p-th tree nodes in the route search table TBL1 will be described. The nodes L1 and L2 in FIG. 9A have a relationship in which the node L1 is a parent node and the node L2 is a child node. FIG. 9B shows a state where an additional node LA1 having the node L2 as a child node is written on the route search table TBL1. Even if the route search processing is executed in this state, the search processing can be executed as usual because the search is performed in the order of the nodes L1 → L2. In FIG. 9C, the pointer of the child node of the node L1 is changed from the node L2 to the node LA1, and the node addition processing is completed.
[0072]
In the following, according to this node addition order rule, an example of 2 p-th power tree nodes and the order to be updated for each of the four additional patterns will be shown.
[0073]
FIG. 10 shows a method for updating a p-th power tree of 2 in (A-1). The updated node is one of the nodes S1. FIG. 10 shows a case where one 2 p-th tree node is updated. The 2 p-th power tree node L1 including the node S1 is changed.
[0074]
FIG. 11 shows a method for updating a p-th power tree of 2 in (A-2). The updated binary tree nodes are three nodes S1, SA1, and SA2. FIG. 11A shows a case where one 2 p-th power tree node is updated. The 2 p-th power tree node L1 including the nodes S1, SA1, and SA2 is changed. FIG. 11B shows a case where two 2 p-th power tree nodes are updated. A 2 pth power tree node LA1 including the node SA1 is added, and the node LA1 is changed to be connected to the child node pointer of the 2 p power tree node L1 including the nodes S1 and SA2. FIG. 11C shows a case where two 2 p-th power tree nodes are updated. A 2 pth power tree node LA1 including nodes SA1 and SA2 is added, and the node LA1 is changed to be connected to the child node pointer of the 2 p power tree node L1 including the node S1. FIG. 11D shows a case where three 2 p-th tree nodes are updated. A 2 p-th power tree node LA1 including the node SA1, a 2 p-th power tree node LA2 including the node SA2, and a node to the child node pointer of the 2 p-th power tree node L1 including the node S1 Change to connect LA2.
[0075]
FIG. 12 shows a method for updating the p-th power tree of 2 in (A-3). The updated binary tree nodes are two nodes S1 and SA1. FIG. 12A shows a case where one 2 p-th power tree node is updated. The 2 p-th power tree node L1 including the nodes S1 and SA1 is changed. FIG. 12B shows a case where two 2 p-th power tree nodes are updated. A 2 pth power tree node LA1 including the node SA1 is added, and the node LA1 is changed to be connected to the child node pointer of the 2 p power tree node L1 including the node S1.
[0076]
FIG. 13 shows a method of updating the 2 p-th power tree in (A-4). The updated binary tree nodes are two nodes S1 and SA1. FIG. 13A shows a case where one 2 p-th power tree node is updated. The 2 p-th power tree node L1 including the nodes S1 and SA1 is changed. FIG. 13B shows a case where one 2 p-th power tree node is updated. The 2-p power tree L2 including the node SA1 is changed, and the 2-p power tree L1 including the node S1 is not updated. FIG. 13C shows a case where two 2 p-th power tree nodes are updated. A 2 pth power tree node LA1 including the node SA1 is added, and the node LA1 is changed to be connected to the child node pointer of the 2 p power tree node L1 including the node S1.
[0077]
Next, a method for deleting a route information entry from the route search table TBL1 having a p-th tree structure of 2 will be described. In the description of the reference technique described above, when an entry is deleted from the binary tree structure, the binary tree node is updated with four deletion patterns. To reflect one or more 2 p-th tree nodes. The order of the nodes to be updated is updated from the child node to the parent node among the nodes to be updated, thereby enabling a route search process between the nodes.
[0078]
A method for adding a 2 p-th tree node in the route search table TBL1 will be described with reference to FIG. In FIG. 14A, the nodes L1, LD1, and L2 have a relationship in which the child node of the node L1 is the node LD1, and the child node of the node LD1 is the node L2. FIG. 14B shows a state where the pointer of the child node of the node L1 is changed from the node LD1 to the node L2. Even if the route search processing is executed in this state, the search processing can be executed as usual because the search is performed in the order of the nodes L1 → L2. FIG. 14C shows a state in which the node LD1 is deleted and the node deletion processing is completed.
[0079]
In the following, according to this node deletion order rule, an example of 2 p-th power tree nodes and the order to be updated for each of the four deletion patterns will be shown.
[0080]
FIG. 15 shows a method for updating the p-th power tree of 2 in (D-1). The updated node is one of the nodes S1. FIG. 15 shows a case where one 2 p-th tree node is updated. The 2 p-th power tree node L1 including the node S1 is changed.
[0081]
FIG. 16 shows a method for updating the p-th power tree of 2 in (D-2). There are three updated binary tree nodes, nodes S1, SD1, and SD2. FIG. 16A shows a case where one 2 p-th power tree node is updated. The 2 p-th tree node L1 including the nodes S1, SD1, and SD2 is changed. FIG. 16B shows a case where two 2 p-th power tree nodes are updated. The child node pointer of the 2 p power tree node L1 including the nodes S1 and SD2 is changed from the node LD1 to the node L2, and the 2 p power tree node LD1 including the node SD1 is deleted. FIG. 16C shows a case where two 2 p-th power tree nodes are updated. The child node pointer of the 2 p power tree node L1 including the node S1 is changed from the node LD1 to the node L2, and the 2 p power tree node LD1 including the nodes SD1 and SD2 is deleted. FIG. 16D shows a case where three 2 p-th tree nodes are updated. The child node pointer of the 2 p power tree node L1 including the node S1 is changed from the node LD2 to the node L2, the 2 p power tree node LD2 including the node SD2 is deleted, and the 2 p power including the node SD1 is deleted. Delete the branch tree node LD1.
[0082]
FIG. 17 shows a method for updating a p-th power tree of 2 in (D-3). The updated binary tree nodes are two nodes S1 and SD1. FIG. 17A shows a case where one 2 p-th power tree node is updated. The 2 p-th power tree node L1 including the nodes S1 and SD1 is changed. FIG. 17B shows a case where two 2 p-th tree nodes are updated. The child node pointer of the 2 p power tree node L1 including the node S1 is changed from the node LD1 to NULL, and the 2 p power tree node LD1 including the node SD1 is deleted.
[0083]
FIG. 18 shows a method of updating the p-th power tree of 2 in (D-4). The updated binary tree nodes are two nodes S1 and SD1. FIG. 18A shows a case where one 2 p-th power tree node is updated. The 2 p-th power tree node L1 including the nodes S1 and SD1 is changed. FIG. 18B shows a case where two 2 p-th power tree nodes are updated. The 2-p power tree L2 including the node SD1 is changed, and the 2-p power tree L1 including the node S1 is not updated. FIG. 18C shows a case where two 2 p-th tree nodes are updated. The child node pointer of the 2 p power tree node L1 including the node S1 is changed from the node LD1 to the node L2, and the 2 p power tree node LD1 including the node SD1 is deleted.
[0084]
Next, when adding or deleting (m−1) bits of route information from mask length 0 bit (step FC10 in FIG. 4), the route of the 2 p-th power tree node existing under the updated binary tree node A method for updating information (step FC3 in FIG. 4) will be described. The route information setting method is similar to the method described in the previous method for converting the p-stage binary tree to the p-th power tree of 2 and the path information of the node in the parent node direction is greater than the path information of the node in the parent node direction. The route information of the node is prioritized, and when the node in the child node direction does not have the route information, when the node in the parent node direction has the route information, the route information is inherited.
[0085]
A method of adding route information having a mask length of 0 to (m−1) bits will be described with reference to FIG. In FIG. 19A, the twelfth node from the first node in the binary tree is set to 2 13 first-stage nodes in the sixteen tree. When route information is added to the node S1 from the state of FIG. 19A, nodes A000, A101, A110, A111, B000, B001, for which route information has not been set in L1 and L2, as shown in FIG. 19B. Is set with the route information * S1.
[0086]
A method of deleting route information of (m−1) bits from mask length 0 bits will be described with reference to FIG. FIG. 20A summarizes the twelfth node from the first node in the binary tree into 2 13 power nodes in the sixteen tree. When the route information of the node S1 is deleted from the state of FIG. 20A, the nodes A000, A101, A110, A111, B000, and B001 having * S1 in the route information in L1 and L2, as shown in FIG. Route information is lost.
[0087]
Next, a processing method for comparing the destination address of the received packet 51 with the control route information will be described. Since the conventional route search table holds only route information necessary for packet relay, after performing route search processing on the destination address of the packet 51 received by the router, further route information required for packet relay. In the router device of this embodiment, the control route information is additionally registered in the route search table TBL1, and the route search processing and the confirmation of the control route information are performed. Can be done at once.
[0088]
FIG. 21 shows an example of transferring a packet to the additional mechanism unit. When it is desired to execute processing by the additional mechanism unit F3 on the packet 51 having the broadcast address as the destination address, the destination address of the received packet 51 is the broadcast address by registering the broadcast address as control route information in the route search table TBL1. If there is, the route search unit F1 identifies the packet 51 as a broadcast packet by the route search unit F1, and the route search unit F1 transfers the packet 51 to the additional mechanism unit F3.
[0089]
As described above in detail, according to the router device of the present embodiment, a route search that holds a route search table TBL1 that stores route information in a 2 p-th-ary tree structure that holds 2 m powers of the first stage. The path management table TBL0 that stores the path information in a binary tree structure is held in the preceding stage of the part F1, and when the path information is added or deleted, the binary tree of the path management table TBL0 is stored in the path search table TBL1. By providing the path management unit F0 having a function of converting to a 2 p-th power tree, maintenance of the path search table TBL1 can be realized. As a result, in the route search method of the reference technique, the binary tree search table in which the high-order bits of the address are searched one bit at a time is searched, whereas the binary tree node p-stage is stored in one 2 By using the route search table TBL1 aggregated to the p-th power tree nodes, it is possible to perform p-stage search at a time, which is effective in speeding up the route search.
[0090]
In addition, when the update of a node that holds a plurality of route information occurs due to the addition or deletion of route information, the node necessary for the route search is determined by considering the order of updating the nodes as illustrated in FIG. Nodes can be added or deleted without being separated from the structure. This has the effect of minimizing the search processing interruption time.
[0091]
In addition, by registering control route information other than the route information necessary for packet relay in the route search table TBL1, when the packet 51 to be transferred to the addition mechanism unit F3 is received, it is added from the received route search unit F1. The additional function can be realized by transferring the packet 51 to the mechanism unit F3. As a result of this implementation, the search of the control route information and the route information can be performed simultaneously, compared with the case where the search of the control route information is performed separately from the search of the route information, and the search processing is simplified. is there.
[0092]
The features of the present invention other than those described in the claims are listed as follows.
[0093]
That is,
<1> In a router device that relays packets in a computer network system,
It has a route search table that holds the address of the device to be transmitted next and the line information (hereinafter referred to as route information) to which the device is connected. From the destination address of the received packet, the router device to be transmitted next A route search function that searches the route search table for the address and line information to which the router device is connected or the line information to which the host indicated by the destination address is connected;
A route management function that has a route management table and updates route information in the route search table;
The route management table stores the route information in the binary tree structure in ascending order of the mask length of the address, and has a degenerated configuration that leaves the node having the route information and the node where the branch occurs,
The route search table is composed of one binary tree node and a total of (2 p-1) binary tree nodes connected immediately below the binary tree node. Aggregate the nodes, embed the route information assigned to the nodes above the node into the 2 (p−1) th power binary tree nodes at the lowermost level, and set the 2 pth power tree nodes to 2 In a 2 p-th power tree structure composed of 2 (p-1) power trees, the tree is stored in ascending order of the mask length of the address, and the node having the path information and the node where the branch occurs are stored. Take the degenerate structure to leave,
The route management unit determines the position of the binary tree node to be added, deleted, or changed from the parent-child relationship between the binary tree nodes in the binary tree structure of the route management table when route information addition / deletion processing occurs. Decide and update the binary tree structure, and update the 2 p-th tree nodes that need to be added, deleted, or changed to the 2 p-th tree structure in the path search table from the update result of the binary tree structure A route search table creation method characterized by:
[0094]
<2> In the route search table creation method described in item <1>, values that can be taken from the 0th bit to the (m−1) th bit of the destination address for the mth power of the first stage node 2 having a mask length of m bits. When the route information from the mask length 0 bit to (m−1) bits is added or deleted when the one-to-one correspondence is made, the first node address is masked with the mask length of the route information. When a plurality of first-stage nodes matching the address do not have route information, the route information is set, and when the route information from mask length 0 bit to (m−1) bits is deleted, the first row node having the route information is set. A route search table creation method characterized by updating the first node by deleting the route information of the node.
[0095]
<3> In the route search table creation method according to item <1>, when adding, deleting, or changing 2 p-th power tree nodes of the route search table for each entry, adding one route information Therefore, when adding a node between nodes in a parent-child relationship, after connecting the addition target node and the child node, connect the parent node and the addition target node, and select a node that has a parent and a child to delete one route information. When deleting, after connecting the parent node of the node to be deleted with the child node of the node to be deleted, deleting the node to be deleted allows the node to be added or deleted without separating the nodes necessary for route search from the tree structure. A route search table creation method characterized by being realized.
[0096]
<4> In the route search table creation method according to item <1> or <2>, when additional functions are added to the route management function and the route search function, an additional mechanism is newly added, and the route necessary for packet relay Control route information other than information is additionally registered in the route search table, and when the destination address of the received packet matches the control route information, the additional function is realized by transferring the packet from the route search function to the additional mechanism. Route search table creation method.
[0097]
Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.
[0098]
【The invention's effect】
According to the information relay method of the present invention, it is possible to increase the speed by dynamically converting a Radish Tree having a binary tree structure into a p-th power tree structure of 2.
[0099]
According to the information relay method of the present invention, it is possible to shorten the route search stop time associated with the update of the route control information and to realize the speedup of the relay control.
[0100]
According to the information relay method of the present invention, when a Radish Tree having a binary tree structure is converted to a p-th power tree structure of 2 to increase the speed, the dynamic update of the p-th power tree structure of 2 is performed. There is an effect that it can be performed accurately in a shorter route search stop time.
[0101]
According to the information relay method of the present invention, when adding, deleting, and changing 2 p-th power tree nodes of a route search table for each entry, nodes necessary for route search are not separated from the tree structure. By adding and deleting nodes, it is possible to minimize the search interruption time.
[0102]
According to the information relay method of the present invention, it is possible to easily expand the function of the computer network by adding the control route information assigned to the special function of the computer network to the route search table. can get.
[0103]
In addition, according to the information relay apparatus of the present invention, an effect is obtained in which a Radish Tree having a binary tree structure can be dynamically converted into a p-th tree structure of 2 to increase the speed.
[0104]
According to the information relay device of the present invention, it is possible to shorten the route search stop time associated with the update of the route control information and to realize the speedup of the relay control.
[0105]
According to the information relay apparatus of the present invention, when a Radish Tree having a binary tree structure is converted to a p-th power tree structure of 2 to increase the speed, the dynamic update of the 2 p-th power tree structure is performed. There is an effect that it can be performed accurately in a shorter route search stop time.
[0106]
According to the information relay apparatus of the present invention, when adding, deleting, and changing 2 p-th power tree nodes of a route search table for each entry, nodes necessary for route search are not separated from the tree structure. By adding and deleting nodes, it is possible to minimize the search interruption time.
[0107]
According to the information relay apparatus of the present invention, by adding the control route information assigned to the special function of the computer network to the route search table, the function of the computer network can be easily expanded. can get.
[Brief description of the drawings]
FIG. 1 is a functional block diagram showing an example of a configuration of a router device that is an embodiment of an information relay device that implements an information relay method of the present invention.
FIG. 2 is a conceptual diagram showing an example of a data structure of a binary tree node of a route management table in a router device which is an embodiment of an information relay device that implements the information relay method of the present invention.
FIG. 3 is a conceptual diagram showing an example of a data structure of a 2 p-th tree node in a route search table in a router device which is an embodiment of an information relay device that implements the information relay method of the present invention.
FIG. 4 is a flowchart showing an example of an operation triggered by the addition or reduction of route information in a router device which is an embodiment of an information relay device that implements the information relay method of the present invention.
FIGS. 5A and 5B are examples of conversion of path information from a binary tree to a 16-tree in a router device that is an embodiment of an information relay device that implements the information relay method of the present invention. FIG.
FIGS. 6A and 6B show an example of processing when addition of route information occurs in a router device which is an embodiment of an information relay device that implements the information relay method of the present invention. It is a conceptual diagram.
FIGS. 7A and 7B show an example of processing when deletion of route information occurs in a router device that is an embodiment of an information relay device that implements the information relay method of the present invention. It is a conceptual diagram.
FIGS. 8A to 8D are 2 p powers generated by addition / deletion of route information in a router device that is an embodiment of an information relay device that implements the information relay method of the present invention; It is a conceptual diagram which shows the example of addition, deletion, and a change of a tree.
FIGS. 9A to 9C are diagrams illustrating a method of adding 2 p-th tree nodes in a route search table in a router device as an embodiment of an information relay device that implements the information relay method of the present invention; It is a conceptual diagram which shows an example.
FIG. 10 is a conceptual diagram showing an example of update processing of a 2 p-th power tree node generated by addition of path information in a router device that is an embodiment of an information relay device that implements the information relay method of the present invention. It is.
FIGS. 11A to 11D are two p-th power tree nodes generated by adding route information in a router device as an embodiment of an information relay device that implements the information relay method of the present invention; It is a conceptual diagram which shows an example of the update process of.
FIGS. 12A and 12B are two p-th power tree nodes generated by adding route information in a router device which is an embodiment of an information relay device that implements the information relay method of the present invention; It is a conceptual diagram which shows an example of the update process of.
FIGS. 13A to 13C are two p-th power tree nodes generated by adding route information in a router device that is an embodiment of an information relay device that implements the information relay method of the present invention; It is a conceptual diagram which shows an example of the update process of.
FIGS. 14A to 14C are diagrams illustrating a method of deleting a 2 p-th power tree node in a route search table in a router device according to an embodiment of an information relay device that implements the information relay method of the present invention; It is a conceptual diagram which shows an example.
FIG. 15 shows an example of update processing of a 2 p-th power tree node generated by deletion of route information in a route search table in a router device which is an embodiment of an information relay device implementing an information relay method of the present invention. FIG.
FIGS. 16A to 16D are diagrams of 2 p generated by deletion of route information in a route search table in a router device which is an embodiment of an information relay device that implements the information relay method of the present invention; It is a conceptual diagram which shows an example of the update process of a multiplication tree node.
FIGS. 17A and 17B show 2 p generated by deletion of route information in the route search table in the router device which is an embodiment of the information relay device that implements the information relay method of the present invention; It is a conceptual diagram which shows an example of the update process of a multiplication tree node.
FIGS. 18A to 18C are 2 p generated by deletion of route information in a route search table in a router device which is an embodiment of an information relay device that implements the information relay method of the present invention; It is a conceptual diagram which shows an example of the update process of a multiplication tree node.
FIGS. 19A and 19B are conceptual diagrams illustrating an example of route information addition processing in a router device that is an embodiment of an information relay device that implements the information relay method of the present invention. FIGS.
FIGS. 20A and 20B are conceptual diagrams showing an example of a route information deletion process in a router device that is an embodiment of an information relay device that implements the information relay method of the present invention.
FIG. 21 is a conceptual diagram illustrating an example of a transfer procedure of a received packet to an addition mechanism unit in a router device which is an embodiment of an information relay device that implements the information relay method of the present invention.
FIG. 22 is a conceptual diagram showing an example of the configuration and operation of a router device which is a reference technique of the present invention.
FIG. 23 is a conceptual diagram illustrating a data structure used in a route control table in a router device which is a reference technique of the present invention.
FIG. 24 is a conceptual diagram illustrating the configuration of a route information table in a router device which is a reference technique of the present invention.
FIG. 25 is a conceptual diagram illustrating the operation of a router device which is a reference technique of the present invention.
FIG. 26 is a conceptual diagram illustrating the operation of a router device that is a reference technique of the present invention.
FIGS. 27A and 27B are conceptual diagrams illustrating the operation of a router device that is a reference technique of the present invention.
FIGS. 28A and 28B are conceptual diagrams illustrating the operation of a router device that is a reference technique of the present invention. FIGS.
FIG. 29 is a conceptual diagram illustrating the operation of a router device that is a reference technique of the present invention.
[Explanation of symbols]
50 ... port, 51 ... packet, 100 ... binary tree node, 101 ... pointer to parent node, 102 ... pointer to child node, 103 ... pointer to child node, 104 ... flag, 105 ... flag, 106 ... child Mask length of 107 node, 107 ... mask length of child node, 108 ... subnetwork address, 109 ... next hop address, 110 ... output port number, 200 ... p-th tree node of 2 ..., 201 ... pointer to child node , 202 ... Flag, 203 ... Mask length of child node, 204 ... Subnetwork address, 205 ... Next hop address, 206 ... Output port number, CE ... Control route information entry, E ... Route information entry, F0 ... Route management unit F1... Route search unit, F3... Additional mechanism unit, TBL0... Route management table, TBL1.

Claims (3)

A routing control table that holds routing information including the address of a relay destination to which the packet is to be transmitted next and line information corresponding to the relay destination in each of a plurality of information relay devices that relay the packet in the computer network In each of the information relay apparatuses, the relay destination to which the packet is to be sent next is determined based on the route information obtained by searching the route control table with the destination address of the received packet. Information relay method,
The routing table is
The path information is stored in each binary tree node of the binary tree structure in ascending order of the mask length of the address, and the binary tree node having the path information and the binary tree node where the branch occurs are left and degenerated. A route management table that takes
Aggregating one binary tree node and a total of (p-1) stages of binary tree nodes (2 to the power of p-1) directly below it into one 2 p power tree node, The route information allocated to the binary tree node at the upper stage of the binary tree node is embedded in the aggregated 2 (p-1) binary tree nodes at the lowermost stage. 2 p-th powers having the path information are stored in a 2 p-th power tree structure composed of 2 (p-1) powers of the binary tree in ascending order of the mask length of the address. A path search table having a degenerated structure leaving a tree node and 2 p-th tree nodes where branching occurs;
Consisting of
When the route information is added, deleted, or changed, the position of the binary tree node to be added, deleted, or changed is determined from the parent-child relationship between the binary tree nodes in the binary tree structure of the route management table. The binary tree structure is determined and updated, and the 2nd p-tree structure of the path search table that needs to be added, deleted, or changed based on the update result of the binary tree structure. Update the p-th power tree node of
Determining the relay destination to which the packet is to be transmitted next based on the path information obtained by searching the second p-th tree node of the path search table with the destination address of the received packet; An information relay method characterized by the above. The information relay method according to claim 1,
In the path search table, when the mth power of the first-stage node 2 having a mask length of m bits is associated with values that can be taken from the 0th bit to the (m-1) th bit of the destination address on a one-to-one basis, When adding the route information from 0 bit to (m−1) bits, if the address of the first node is masked with the mask length of the route information, a plurality of the first node matching the address of the route information When the path information is set when the path information does not have the path information and the path information from the mask length 0 bit to (m−1) bits is deleted, the path information of the first node having the path information is deleted. The operation of updating the first node by,
When adding, deleting, or changing a 2 p-th power tree node of the route search table for each entry, when adding a node between nodes in a parent-child relationship to add one route information, an addition target After connecting a node and a child node, connect the parent node and the node to be added, and delete a node that has a parent and a child to delete one route information, the parent node of the node to be deleted is a child of the node to be deleted Operation that realizes node addition / deletion without separating the node required for route search from the tree structure by deleting the node to be deleted after connecting to the node,
Control route information other than the route information necessary for packet relay is additionally registered in the route search table in a format equivalent to the route information, and the packet is added to an additional mechanism having a specific additional function corresponding to the control route information. The address and line information included in the control route information is set so that the route information is transferred, and the route information and the control route information registered in the route search table are searched with the destination address of the received packet. An operation for realizing the additional function by transferring a packet to the additional mechanism when the control route information matches the control path information;
An information relay method comprising performing at least one of the following operations. An information relay device that relays packets in a computer network,
A routing control table that holds routing information including the address of the relay destination to which the packet is to be transmitted next and line information corresponding to the relay destination, a route management unit that updates the contents of the routing control table, and the received A route search unit that determines the relay destination to which the packet is to be sent next based on the route information obtained by searching the route control table at a packet destination address; and
The route management unit stores the route information as the route control table in each binary tree node of the binary tree structure in ascending order of the mask length of the address. Has a path management table that takes a degenerated configuration leaving the generated binary tree nodes,
In the route search unit, as the route control table, one binary tree node and a total of (p−1) stages of binary tree nodes (2 to the power of p−1) connected immediately below the binary tree node are 1 The above-mentioned route that is aggregated into two 2 p power tree nodes and allocated to the 2 (p−1) power binary tree nodes in the lowermost stage, which are allocated to the binary tree nodes that are higher than the binary tree node. Embedding information, store 2 p-th power tree nodes in 2 p-th power tree structure consisting of 2 (p-1) powers of binary tree combined in ascending order of mask length of the address. And a path search table having a degenerate structure leaving 2 p-th tree nodes having the path information and 2 p-th tree nodes where branching occurs.
When the route information is added, deleted, or changed, the route management unit should add, delete, or change from the parent-child relationship between the binary tree nodes in the binary tree structure of the route management table 2 Updating the binary tree structure by determining the position of the branch tree node, and adding, deleting, and deleting from the second p-th tree structure of the path search table based on the update result of the binary tree structure; Update the 2 p-th tree node that needs to be changed,
The route search unit performs an operation of determining the relay destination to which the packet is to be sent next based on the route information obtained by searching the route search table with the destination address of the received packet. An information relay device characterized in that it is configured as described above.

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