JP3059639B2 - Route selection information search device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a search device for searching for route selection information for performing data transfer between a plurality of connected networks.

[0002]

2. Description of the Related Art Heretofore, this type of search device has been provided in a router connecting a plurality of networks. The search device has, for each routable network, route selection information including the address of the router to be transferred next, the number of hops, and the like. Was finding routing information for and sending the data to the appropriate network. At this time, the search device uses a hash method,
Each piece of route selection information is linked to a hash value of a hash table using the network number of the network as a key. When searching for the route selection information for a certain network, only the information having the same hash value is searched, so that it is not necessary to search all the information, and the search can be performed in a short time. In the search device, when one network number is assigned to one network, the management and search of the route selection information can be easily performed by the above-described method.

[0003]

In some of the above routers, the range of the number of nodes that can be connected to one network number is defined. In such a case, the connection to one network is possible. When connecting more nodes than the required number of nodes, a plurality of network numbers may be assigned to one network to increase the number of connectable nodes.

However, in such a case, if the search device is used to set the route selection information for each network number, if the range of the assigned network numbers is wide, many There is a problem in that it is necessary to have the route selection information and the storage capacity becomes large. In addition, information has to be added to or deleted from a certain network by the number of the network assigned to the network, so that efficiency is degraded. Furthermore, if route selection information is provided for each network, only one network number can be used as a hash key. Therefore, in the above-described hashing method, other network numbers that are not keys are used. There was a problem that the route selection information could not be found.

The present invention has been made in view of the above problems, and even when a plurality of network numbers are assigned to one network, the corresponding path selection information is obtained from all the network numbers using a hash method. It is an object of the present invention to provide a search device that can search for a search. Another object of the present invention is to provide a search device that can easily add and delete information to and from a network.

A further object of the present invention is to provide a search device which can easily create route selection information.

[0007]

In order to achieve the above object, according to the present invention, there is provided a route selection information for retrieving predetermined route selection information from route selection information stored in a route selection information table by a hash method. A plurality of network numbers assigned to one network, a route selection information table including one of the assigned network numbers as selection key information; A route selection information search table including a network number that is not the selection key information as information and a network number that is the selection key information, and a network number for performing a route selection, as the selection key information, Search the information table, and if there is no corresponding route selection information, The work number, routing information search locate the selected key information is in the network number is in table search means a search device equipped with is provided as search key information.

According to a third aspect of the present invention, when the search means cannot search the route selection information corresponding to the network number for performing the route selection, the search means can search the entire route selection information table and search the corresponding route selection information. In this case, a route selection information search table corresponding to the network number is created, and the created route selection information search table is linked to the corresponding hash value.

[0009]

The above retrieval apparatus has a route selection information table and a route selection information search table. Since the network number as the selection key information corresponding to the network number is searched from the search table, the corresponding route selection information can be easily searched. Since there is one route selection information table for one network, it is possible to easily add / delete the route selection information.

According to a third aspect of the present invention, when the route selection information cannot be searched, the entire route selection information table is searched, and when the search is successful, a route selection information search table is created and linked to the corresponding hash value. Therefore, for the network number once searched, the route selection information table and the route selection information search table can be searched from the next to obtain the network number serving as the selection key.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram showing a schematic configuration of a search device according to the present invention. In the figure, a search device is provided in each router connecting a plurality of networks, as in the conventional example. The search device has a route selection information table 11 having a hash structure and having route selection information; a route selection information search table 12 having a hash structure and having search information; On the other hand, it comprises a search means 13 for searching for route selection information and search information.

The route selection information table 11 is composed of a route selection information hash table 11a comprising a plurality of arbitrarily set hash values, and route selection information provided corresponding to the hash values. . In this embodiment, the hash value of the route selection information hash table 11a has an arbitrary number from [0], and a plurality of pieces of route selection information are provided corresponding to the hash value. Here, for convenience of explanation, the route selection information A1, A2 corresponding to the hash value [a] and the route selection information A3, A4 corresponding to the hash value [b] are shown.

That is, in the present embodiment, when a plurality of network numbers are assigned to one network, the first network numbers X1 to X1 of the allocation range of the network numbers assigned to the network are assigned.
X4, the final network numbers Y1 to Y4, and the routing information A1 to A4 including the address of the router to be transferred next, the number of hops, etc. (not shown) for each routable network. I have one.

In this embodiment, each route selection information A1
A4 to A4 have matching hash-calculated values using the first network numbers X1 to X4 as selection key information.
Although it is linked to the above hash value, the present invention is not limited to this. For example, the hash value with the most frequently used network number among the network numbers assigned to the network as the selection key information It is also possible to link.

The route selection information search table 12 comprises a route selection information search hash table 12a comprising a plurality of arbitrarily set hash values, and search information provided corresponding to the hash values. I have.
In the present embodiment, the hash value of the route selection information search hash table 12a has an arbitrary number from [0], and a plurality of search information are provided corresponding to the hash value. Here, for convenience of explanation, search information B1, B2 corresponding to the hash value [aa] and search information B3, B4 corresponding to the hash value [bb] are shown.

That is, in this embodiment, the search information B1 to B4 including the network numbers Z1 to Z4 other than the first network numbers X1 to X4 in the range of the network numbers and the first network numbers X1 to X4, respectively. To
It has one for each network number that is not the top.
In the present embodiment, each of the search information B1 to B4 is linked to the above-mentioned hash value by using the network number Z1 to Z4 which is not the top as the search key information and matching the hash value. However, the present invention is not limited to this. For example, when a frequently used network number is used as selection key information, a network number other than the frequently used network number is linked to a hash value as search key information. It is also possible.

The retrieval means 13 retrieves, using the hash retrieval algorithm, the path selection information linked by the hash value of the path selection information hash table 11a which has been hashed using the network number as a key. The search means 13 finds the route information for the destination network of the data from the linked route selection information, whereby the router can transmit the data to an appropriate network.

If there is no corresponding route selection information, the search means 13 searches for search information linked by the hash value in the route selection information search hash table 12a. Here, the search means 13 searches the linked search information for the first network number corresponding to the corresponding network number. And
A hash calculation is performed using the searched top network number as selection key information. Then, the search means 13
The route selection information linked by the calculated hash value of the route selection information hash table 11a is searched.

If there is no corresponding search information, the search means 13 searches the route selection information table, and if there is such search information, the search means 13 becomes a target when searching for the route selection information. A route selection information search table of the network number is generated. The generation of the route selection information search table is performed by the search means 13, and when searching for the same network number once searched, the above-mentioned route selection information search table and the route selection information search table will be described below. By searching, the first network number serving as the route selection key can be obtained, and the procedure for searching the entire route selection information table is eliminated.

Next, a search operation for searching for route selection information for a certain network number will be described with reference to FIGS. FIG. 2 is a diagram illustrating an example of a system in which a plurality of networks are connected using a router in which the search device according to the embodiment is provided. In the figure, a router 20 is connected to networks 1, 2, 5 respectively. The router 21 is connected to the networks 3 and 5, respectively. The router 22 is connected to the networks 2 and 6, respectively. The router 23 is connected to the networks 4, 6, and 7, respectively. The router 24 is connected to the networks 1 and 8, respectively. The router 25 is connected to the networks 6 and 9, respectively. Further, the router 26 is connected to the networks 7, 1
0.

Here, for example, the network 1
01 "to" 2000 ", network 2 is a network number in the range of" 101 "to" 180 ", and network 3 is a network number in the range of" 11 "to" 5 ".
It is assumed that the network number has a network number in a range of “0” and the network 4 has a network number in a range of “10001” to “10005”.

In such a state, each router has, for example, a routing information table 11 having a hash structure as shown in FIG. 3 and a routing information search table 12 as shown in FIG. That is, in the route selection information table 11, the route selection information A1 includes the first network number “1001” and the last network number “2000” of the network 1, and the route selection information A2 includes The first network number “101” and the last network number “180” are included. The route selection information A1 and A2 are linked to the hash value [a] of the hash value calculated route selection information hash table 11a using the head network number as the selection key information.

The route selection information A3 includes the first network number "11" and the last network number "50" of the network 3, and the route selection information A4 includes
The first network number “1000” of the network 4
1 "and the final network number" 10005 ". The route selection information A3 and A4 are linked to the hash value [b] of the hash value calculated route selection information hash table 11a using the head network number as the selection key information.

In the route selection information search table 12, the search information B1 includes a network number "156" in the number range of the network 2 and a head network number "101". Is
For example, the network number “10005” in the number range of the network 1 and the first network number “100”
1 "is included. The search information B1 and B2 include a network number “15” other than the head network number.
6 ”and“ 10005 ”as search key information, which are linked to the hash value [aa] of the hash value calculated route selection information search hash table 12a.

The search information B3 includes, for example, the network number "30" in the number range of the network 3 and the head network number "11".
4 includes, for example, the network number “160” in the number range of the network 4 and the first network number “1”.
01 ”is included. The search information B3, B4 includes a network number "3" other than the head network number.
Using “0” and “160” as search key information, the hash value is linked to the hash value [bb] of the hash value calculated route selection information search hash table 12a.

In such a state, for example, when the route selection information is searched for the network number "1001", since the above "1001" is the head of the range of the network number, the search means 13 determines the route selection information. By following the link of the hash value [a] in the hash table 11a, the corresponding route selection information A1 can be found.

For example, the network number "160"
When searching for the route selection information, first, the link of the hash value of the route selection information hash table 11a hashed by the network number is followed. But,
Since the network number is not the head of the range of the network number, the search unit 13 cannot find the corresponding route selection information. Then, next, the search means 1
3 is a hash value [b of the route selection information search hash table 12a hash-calculated with the network number.
b], the corresponding search information B4
Can be found. Then, "10" which is the head network number stored in the search information B4
From "1", by following the link of the hash value [a] in the hash value calculated route selection information hash table 11a, the corresponding route selection information A2 can be found.

Further, when the route selection information corresponding to the new network number is searched, that is, when the route selection information table 11 and the route selection information search table 12 cannot be obtained even if the route selection information and the route selection information cannot be obtained. In the search means 13, the route selection information table 1
All the route selection information stored in No. 1 is searched in order to find a corresponding one. Next, the search information is linked to the hash value of the route selection information search hash table 12a hash-calculated with the searched network number to create a route selection information search table.

As described above, at each router, at first,
Although there is no routing information search table for any network number, once the routing information is searched, there is a routing information search table for that network number. Therefore, in this embodiment,
Even when a plurality of consecutive network numbers are assigned to one network, a two-stage hash search is performed using a route selection information search table in addition to the route selection information table, so that all routable routes are available. Instead of managing the routing information for the network number of the network, it is only necessary to search some of the search information and the routing information linked to the corresponding hash value,
The corresponding route selection information can be found in a short time.

Further, in this embodiment, since there is one route selection information table for one network, it is possible to easily add / delete information for the network. Furthermore, in this embodiment, the search means creates the route selection information search table corresponding to the network number and links the created route selection information search table to the corresponding hash value, so that the route selection information can be easily created. Can be done.

Thus, in the present embodiment, it is possible to accurately and easily find the routing information for the destination network of the data from the routing information and transmit the data to an appropriate network. Transfer reliability can be improved.

[0032]

As described above, according to the present invention, in a route selection information search device for searching for predetermined route selection information from route selection information stored in a route selection information table by a hash method, When a plurality of network numbers are assigned to one network, a path selection information table including one of the assigned network numbers as selection key information, and the selection key as search key information. A route selection information search table including a network number that is not information and a network number that is the selection key information, and a network number for performing route selection,
As the selection key information, a route selection information table is searched. If there is no corresponding route selection information, the network number is used as the search key information in the route selection information search table. Since search means for searching for numbers are provided, even when a plurality of network numbers are assigned to one network, it is possible to search for the corresponding route selection information from all the network numbers using the hash method, and Since there is one route selection information table for one network, it is possible to easily add / delete information for the network.

According to the third aspect, when the route selection information corresponding to the network number for performing the route selection cannot be searched, the search means can search all the route selection information tables and search the corresponding route selection information. In this case, a route selection information search table corresponding to the network number is created, and the created route selection information search table is linked to the corresponding hash value, so that the route selection information can be easily created. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a schematic configuration of a search device according to the present invention.

FIG. 2 is a diagram illustrating an example of a system in which a plurality of networks are connected by using a router in which a search device according to the embodiment is provided.

FIG. 3 is a diagram showing a specific example of a route selection information table shown in FIG. 1;

FIG. 4 is a diagram showing a specific example of a route selection information search table shown in FIG. 1;

[Explanation of symbols]

11 Route selection information table 11a Route selection information hash table 12 Route selection information search table 12a Route selection information search hash table 13 Search means A1 to A4 Route selection information B1 to B4 Search information X1 to X4 First network number Y1 to Y4 Last Network number Z1 to Z4 Network numbers other than the first network number

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shuichi Saito 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (56) References JP-A-6-244840 (JP, A) JP-A-Hei 6-162095 (JP, A) JP-A-6-69927 (JP, A) JP-A-5-81102 (JP, A) JP-A-3-54937 (JP, A) (58) Fields investigated (Int. Cl. ^7, DB name) G06F 17/30 H04L 12/28 JICST file (JOIS)

Claims (3)

(57) [Claims] 1. A route selection information search device that searches for predetermined route selection information from stored route selection information by a hash method, wherein a plurality of network numbers are assigned to one network. A route selection information table including one network number of the assigned network numbers as selection key information, a network number that is not the selection key information as search key information, and the selection key information. A search device comprising: a route selection information search table that includes a network number that is located; and search means that searches the route selection information table and the route selection information search table for route selection information for the network. 2. The search means searches a route selection information table using a network number for which a route is to be selected as the selection key information. If there is no corresponding route selection information, the network number is searched by a search key. 2. The search device according to claim 1, wherein a search is performed on a route selection information search table as information, and a network number serving as the selection key information is searched for in the route selection information search table. 3. When the search means cannot search the route selection information corresponding to the network number for performing the route selection, it searches all of the route selection information tables and searches the corresponding route selection information. 3. The search device according to claim 2, wherein a route selection information search table corresponding to the network number is created, and the created route selection information search table is linked to a corresponding hash value.