JPH11289345A - Router device and set method for transmission route - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a router device and a transmission route, which is able to reduce a load of cache table deletion accompanying changes, including deletion of a routing table, and to provide a set method for a transmission route. SOLUTION: Accompanying a routing entry number, a network address and the like as an IP address for indicating the destination network is stored in a routing table 101, a host address is stored in a cache table 201 by accompanying a cache entry number and data, which indicate a coordinate relation between the routing entry number and the cache entry number are stored in a cache management table 301, and on the basis of the data for indicating a corresponding relation stored in this cache management table 301, an entry stored in the cache table is deleted at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a router device and a transmission route setting method, and more particularly to a router device and a transmission route setting method capable of deleting entries in a cache table at high speed.

[0002]

2. Description of the Related Art At present, as the demand for data communication increases,
Although various communication technologies have been developed, Lo is a local communication network centered on communication for computers.
A cal Area Network (hereinafter simply referred to as LAN) is provided and frequently used.

In addition, with the spread of LAN, a plurality of LA
It is becoming increasingly popular to interconnect networks N to expand the scale and utility of the network. And these, LAN
Interface devices such as repeaters, bridges, routers, and gateways have been developed to connect between them.

[0004] Among the above interface devices, routers have become mainstream interface devices between LANs because they can be connected via different types of LANs and their structures are simple. Has become.

FIG. 5 shows a conventional router device.
This will be described with reference to FIG. FIG. 5 shows a block diagram of a configuration of a conventional router device.

A conventional router device 501 shown in FIG.
Controls transmission of a packet which is a unit for transmitting data.

The router device 501 includes a main control unit 502
And three interface units 531, 532, and 53
3 and a switch unit 504.

The main control unit 502 includes a protocol processing unit 50
5, a routing table 101, a forwarding processing unit 506, and a cache management unit 507.

Each interface unit includes a cache table 201, a physical termination unit 508, and a cache search processing unit 509.

The router 501 determines a destination interface for a destination address of a received packet in order to control the transmission of a packet as a unit for transmitting data. This determination is made in one place of the router 501. If the processing is performed intensively, a high throughput cannot be obtained because access to that part is concentrated.

Therefore, a router device for a backbone network that requires high throughput employs an architecture that separates route search processing and routing protocol processing.

More specifically, the determination of the transmission interface and the header processing of the packet accompanying the forwarding are as follows:
A route search unit distributed in each interface unit performs processing of a routing protocol, creation of a routing table, and distribution of routing information to each interface unit.

Therefore, as one example of realizing such an architecture, as shown in FIG. 5, there is a technique for holding the correspondence between the destination host address and the transmission interface as a cache table 201 arranged in each interface unit. .

However, in the case of the router 501 as shown in FIG. 5, when a packet addressed to a certain destination address is received by the router 501 for the first time, the transmission table of the transmission interface corresponding to the destination address of this packet is stored in the cache table 201. Because there is no information, the main control unit 50
In the second forwarding processing unit 506, a packet transfer process is performed based on a search for information stored in the routing table 101.

The packet transfer processing operation in this case will be described. The forwarding processing unit 506 searches the routing table 101 for the received packet transferred from the interface unit, and determines the destination interface number for the destination IP address.

After the IP header is updated, the packet is transferred to the transmission interface unit. At the same time, the cache management unit 507 is requested to register an entry in the cache table 201.

Once the entry information for a certain destination address is registered in the cache table 201, the subsequent packets of that address hit the cache table 201, so that the cache search processing unit 509 in the interface unit The packet is forwarded.

Therefore, in the conventional router device 501 as shown in FIG. 5, it is assumed that the received packet can be efficiently transferred.

[0019]

The operation when the information stored in the routing table 101 is changed will be described. When an entry in the routing table 101 is deleted or when the content of the entry is changed, the cache entry generated by referring to the entry and stored in the cache table 201 must be deleted.

Conventionally, a router device 5 as shown in FIG.
01, delete the cache in the routing table 1
This is performed based on the information of the network address and the net mask of the entry No. 01.

For this reason, in the cache management unit 507,
For all entries in the cache table 201, it is checked whether the destination host address of the entry matches the range of the network address and the netmask of the entry of the deleted routing table 101, and only the cache entry that matches is selected and deleted. And there is a problem that the load of the deletion is large.

The deletion operation in this case will be described with reference to FIGS. 5, 6, and 7. FIG. FIG. 6 shows an example of a routing table stored in the routing table 101 shown in FIG. 5, and FIG. 7 shows an example of a cache table stored in the cache table 201 shown in FIG.

For example, as shown in FIG. 6, consider the case where the entry of the network address aaa0 and the netmask 255.255.255.0 stored in the routing table 101 is deleted.

In this case, the cache management unit 507 performs, for all entries in the cache table 201,
Between the netmask 255.255.255.0 and the destination host address
Find the AND and delete the one that matches the network address aaa0.

In this case, as shown in FIG. 7, the network address aaa1 and the network address aaa
2 and the network address aaa3 match.

In general, in the router device 501 as shown in FIG. 5, in order to improve the throughput, the number of entries in the cache table 201 is increased so that more destination hosts hit the cache. . As a result, the conventional router device has a problem that the load of the above-described deletion processing increases as the number of entries in the cache table 201 increases.

The present invention has been made in view of the above circumstances, and provides a router apparatus and a transmission route setting method capable of reducing the load of cache table deletion accompanying a change including deletion of a routing table. With the goal.

[0028]

According to the first aspect of the present invention,
When interconnecting networks, a router device that determines a data transmission route has a network address as an IP address representing a destination network, a next hop address as an IP address of a next transfer destination router device with respect to a netmask, and transmission. A routing table storing interface numbers, and a link layer (MAC) as an IP address of a destination host.
Header information and a transmission interface number are stored therein, and a routing entry number is assigned to each entry of the routing table means, and a cache entry number is assigned to each entry of the cache table means. And cache management table means for storing data indicating the correspondence between the routing entry number and the cache entry number.

According to a second aspect of the present invention, in the first aspect of the present invention, an entry is registered in the cache table means upon receipt of a cache registration request to the cache table means, and the entry is registered in the cache table means. A cache management unit that generates data representing a correspondence relationship between the cache entry number of the entry and the routing entry number of the entry hit on the routing table unit and outputs the data to the cache management table unit. I do.

According to a third aspect of the present invention, in the second aspect of the present invention, when the entry of the routing table is deleted, and when the contents of the entry of the routing table are changed, other routing protocols are used. When performing the process, the cache management unit includes a protocol processing unit that outputs a deletion request including a routing entry number to the cache management unit.

According to a fourth aspect of the present invention, in the third aspect of the present invention, when the cache management means outputs a deletion request including the routing entry number, the cache management means stores the deletion request in the cache management table means. A cache entry number corresponding to the routing entry number included in the deletion request is obtained by referring to the data, and the entry stored in the cache table means is deleted based on the obtained cache entry number. .

According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, there is provided forwarding processing means for performing forwarding processing on a received packet addressed to the host address. I do.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the forwarding processing means cannot determine a destination interface means by referring to a host address stored in the cache table means. The forwarding process is performed in the case where the error occurs.

According to a seventh aspect of the present invention, in the invention of the fifth or sixth aspect, the forwarding processing means searches the received packet for the routing table means, and searches for the destination IP address of the IP packet. A next hop address and a destination interface number are determined.

According to an eighth aspect of the present invention, in the invention of the seventh aspect, when the forwarding processing means searches the routing table means, the destination IP address of the received packet is stored in the routing table means. The method is characterized in that masking is performed by the net mask of all entries, the masked value is compared with the network address, and among the matched ones, the one having the largest bit length of the mask is regarded as a hit. I do.

According to a ninth aspect of the present invention, in the invention according to any one of the fifth to eighth aspects, the forwarding processing means includes a TTL (Time T
oLive) field and checksum update and other header processing associated with the forwarding of IP packets, and link layer processing including addition of an Ethernet MAC header.

The invention according to claim 10 is the invention according to claims 5 to 9
In the invention according to any one of the above, the forwarding processing means refers to a host address stored in the cache table means for the received packet, and when the destination interface means cannot be determined, the forwarding processing means An entry registration request is output to the cache management means.

The eleventh aspect of the present invention is the first aspect of the present invention.
0, wherein the router device comprises: a main control unit including the routing table unit and the cache management table unit; and at least one or more interface units including the cache table unit. It is characterized by having.

According to a twelfth aspect of the present invention, in accordance with the eleventh aspect, the main control means and the at least one
It is characterized by having switch means for connecting each of the above interface means.

According to a thirteenth aspect of the present invention, in the first or the twelfth aspect of the present invention, the interface means includes an Ethernet and an asynchronous transfer mode (AT
M: Asynchronous Transfer M
mode).

The invention according to claim 14 is the invention according to claims 1 to 1
3. The invention according to claim 3, further comprising cache search processing means for searching the cache table means for an IP address of a destination host of the received packet and determining an interface means to transmit.

According to a fifteenth aspect of the present invention, in accordance with the fourteenth aspect, the cache retrieval processing means
The search of the cache table means is performed by comparing the IP address of the destination host of the received packet with the entry of the cache table means, and considering a match as a hit.

According to a sixteenth aspect of the present invention, a network address as an IP address indicating a destination network, a next hop address as an IP address of a next transfer destination router device with respect to a netmask, and a transmission entry number are transmitted. Routing table means for storing an interface number, cache table means for storing a host address along with a cache entry number, and data representing a correspondence between the routing entry number and the cache entry number Cache management table means for deleting entries stored in the cache table means at a high speed based on data representing the correspondence stored in the cache management table means.

According to a seventeenth aspect of the present invention, in the method for setting a data transmission route for interconnecting networks, a network address as an IP address representing a destination network and an IP address of a next transfer destination router device with respect to a netmask are provided. A routing table storing step of storing a next hop address and a transmission interface number as an address in a routing table means, and information of a link layer (MAC header) as an IP address of a destination host and a transmission table number in a cache table means A routing table number is assigned to each entry stored in the routing table means, and a cache entry is assigned to each entry stored in the cache table means. Along with the bird number is assigned,
A cache management table storing step of storing data representing the correspondence between the routing entry number and the cache entry number in a cache management table means.

According to an eighteenth aspect of the present invention, in the invention according to the seventeenth aspect, upon receiving a cache registration request to the cache table means, an entry is registered in the cache table means, and the entry is registered in the cache table means. Said cache entry number of the entry;
A cache management step of generating data representing a correspondence relationship between an entry hit on the routing table means and the routing entry number and outputting the data to the cache management table means.

According to a nineteenth aspect of the present invention, in the invention according to the eighteenth aspect, when the entry of the routing table is deleted, and when the contents of the entry of the routing table are changed, other routing protocols are used. When performing the processing, the cache management step includes a protocol processing step of outputting a deletion request including a routing entry number.

According to a twentieth aspect of the present invention, in the invention according to the nineteenth aspect, when the cache management step outputs a deletion request including the routing entry number, the cache management table is stored in the cache management table means. With reference to the data, a cache entry number corresponding to the routing entry number included in the deletion request is obtained,
An entry stored in the cache table storing step is deleted based on the obtained cache entry number.

According to a twenty-first aspect of the present invention, there is provided any one of the seventeenth to twentieth aspects of the present invention, further comprising a forwarding processing step of performing forwarding processing on a received packet addressed to the address of the host. I do.

According to a twenty-second aspect of the present invention, in the invention according to the twenty-first aspect, the forwarding processing step can determine a destination interface means by referring to a host address stored in the cache table storing step. The forwarding process is performed when there is no forwarding process.

According to a twenty-third aspect of the present invention, in the invention of the twenty-first or twenty-second aspect, the forwarding processing step searches the received packet for contents stored in the routing table means in the routing table storing step. To the destination I of the IP packet
A next hop address for the P address and a destination interface number are determined.

According to a twenty-fourth aspect of the present invention, in the invention according to the twenty-third aspect, the routing table means in the forwarding processing step stores the destination IP address of the received packet in the routing table means. The method is characterized in that masking is performed by the net mask of all entries, the masked value is compared with the network address, and among the matched ones, the one having the largest bit length of the mask is regarded as a hit. I do.

According to a twenty-fifth aspect of the present invention, in the invention according to any one of the twenty-first to twenty-fourth aspects, the forwarding processing step includes the steps of:
eTo Live) field and checksum update, and other header processing associated with the forwarding of IP packets, and link layer processing including addition of an Ethernet MAC header.

According to a twenty-sixth aspect of the present invention, in the invention according to any one of the twenty-first to twenty-fifth aspects, the forwarding processing step refers to a host address stored in the cache table storing step for the received packet. Then, when the interface means of the transmission destination cannot be determined, an entry registration request is output to the cache management step.

The invention according to claim 27 is the invention according to any one of claims 17 to 26, wherein the transmission route setting method includes the routing table storing step and the cache management table storing step. It is characterized by comprising a control step and an interface step of sending data to at least one or more interface means, comprising the cache table storing step.

According to a twenty-eighth aspect of the present invention, in the twenty-seventh aspect, there is provided a switching step of inputting and outputting data between the main control step and the at least one or more interface steps.

According to a twenty-ninth aspect of the present invention, in the invention of the twenty-seventh or twenty-eighth aspect, the interface means for transmitting data in the interface step comprises:
Ethernet and asynchronous transfer mode (ATM: A
Synchronous Transfer Mod
e) at least one of the following.

According to a thirtieth aspect of the present invention, in the invention according to any one of the seventeenth to twenty-ninth aspects, the IP address of the destination host of the received packet is searched from the contents stored in the cache table storing step. hand,
It is characterized by having a cache search processing step of determining an interface means to transmit.

According to a thirty-first aspect of the present invention, in the thirty-third aspect of the present invention, in the cache search processing step, the search of the cache table means includes the step of: Is compared with the entry stored in the file, and a match is regarded as a hit.

According to a thirty-second aspect of the present invention, a network address as an IP address representing a destination network, a next hop address as an IP address of the next transfer destination router device with respect to a netmask, and a transmission entry number are transmitted. A routing table storing step of storing an interface number, a cache table storing step of storing a host address together with a cache entry number, and storing data representing a correspondence between the routing entry number and the cache entry number A cache management table storing step of deleting the entries stored in the cache table storing step at a high speed based on the data stored in the cache management table storing step. That.

Next, the operation of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing a configuration of an embodiment of a router device according to the present invention and a router device to which an embodiment of a transmission route setting method according to the present invention is applied. However, in FIG. 1, the same members as those in FIG. 5 described above are denoted by the same reference numerals.

In the present invention, a routing entry number (hereinafter, also referred to as a routing table entry number) is assigned to each entry of the routing table 101 provided in the main control unit 2, and furthermore, the interface unit 3.
Cache table 2 provided in 1, 32, and 33
01, each entry has a cache entry number (hereinafter referred to as a cache entry number).
Also called a cache table entry number. ).

Further, the main control unit 2 is provided with a cache management table 301 for storing data indicating the correspondence between the routing entry number and the cache entry number. FIG. 4 shows an example of the correspondence between the routing entry number and the cache entry number stored in the cache management table 301.

Therefore, according to the present invention, when the contents stored in the routing table 101 are changed as in the conventional router and the method of setting the transmission route,
The contents stored in the cache management table 301 are obtained without performing an AND operation on all the entries of the cache table 201 with the mask of the entry of the deleted routing table and comparing with the network address. , The entry of the cache table 201 can be deleted at high speed.

[0064]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a router device and a transmission route setting method according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the router device according to the present invention. However, the description of one embodiment of the router device according to the present invention, which is made with reference to FIG. 1 below, also serves as the description of one embodiment of the transmission route setting method according to the present invention. Also, in FIG.
The same reference numerals are given to members similar to.

As shown in FIG. 1, a router device 1 according to the present invention comprises a main control unit 2 and three interface units 3
1, 32, and 33 and the switch unit 4. Here, in FIG. 1, three interface units are shown as the interface units, but the interface unit according to the present invention is not limited to three, and at least one interface unit is provided. I just want to.

As shown in FIG. 1, the main control unit 2 comprises a protocol processing unit 5, a routing table 101, a forwarding processing unit 6, a cache management unit 7, and a cache management table 301.

Each of the interface units 31, 32, and 33 is composed of a physical termination unit 8, a cache search processing unit 9, and a cache table 201.

As described above, the router 1 shown in FIG.
Are the main control unit 2, the interface units 31, 32, and 3
3. The switch unit 4 is connected to the main control unit 2 and the plurality of interface units 31, 32, and 33.

The main control unit 2 and the interface unit 3
Each of 1, 32, and 33 has an interface number, and packets are transferred through the switch unit 4.
Interface units 31 and 3 as external interfaces
There are various types 2 and 33 depending on the physical layer, such as Ethernet and ATM. In the following description, Ethernet will be described as an example.

Next, the operation of each member shown in FIG. 1 will be described. The protocol processing unit 5 exchanges routing information with another router device based on a routing protocol such as RIP or OSPF, thereby transmitting information to be stored in the routing table 101 (hereinafter, this information is referred to as routing information). Create a table.)

The routing table stored in the routing table 101 describes an IP address (network address) representing a destination network, an IP address (next hop address) of a next transfer destination router with respect to a netmask, and a transmission interface number. Is done. In addition, a routing table entry number is assigned to each entry.

Here, the routing table 10 described above is used.
An example of the routing table stored in No. 1 will be described with reference to FIG. FIG. 2 shows an example of a routing table stored in the routing table 101 shown in FIG.

As shown in FIG. 2, the routing table stores a destination network address, a netmask, a next hop address, and a transmission interface number, and each of them is assigned a routing table entry number. However, the present invention is not limited to the case where the routing table of four entries is stored as shown in FIG. 2, and the routing table of any other number of entries may be stored. good.

Next, the forwarding processing section 6 shown in FIG. 1 is a section for performing a forwarding process when a packet addressed to a certain destination IP address is first (first-time) forwarded in the router 1.

The forwarding processing unit 6 performs a forwarding process when a destination interface cannot be determined even after searching the cache tables 201 of the interface units 31, 32, and 33.

The forwarding processing unit 6 searches the routing table 101 for the received packets transferred from the interface units 31, 32 and 33, and determines the next hop address and the destination interface number for the destination IP address of the IP packet. I do.

Also, the TTL (Time To Li
ve) Header processing associated with the forwarding of IP packets, such as updating fields and checksums, and Ethernet
Perform link layer processing such as adding a MAC header to et.

Further, the packet is transferred to the interface units 31, 32 and 33 of the transmission destination via the switch unit 4. At the same time, it outputs a cache entry registration request to the cache management unit 7.

Next, as shown in FIG. 1, the interface units 31, 32, and 33 include a physical termination unit 8, a cache search processing unit 9, and a cache table 201.

The cache table 201 stores a cache table in which link layer (MAC header) information and a destination interface number are described for the IP address of the destination host.

Here, FIG. 3 shows an example of information to be stored in the cache table 201 shown in FIG. 1 (hereinafter, this information is referred to as a cache table).
This will be described with reference to FIG. FIG. 3 shows an example of a cache table stored in the cache table 301 shown in FIG.

As shown in FIG. 3, the cache table includes a destination host address, MAC header information,
And the transmission interface number are stored.
A cache table entry number is assigned. However, the cache table stored in the router device according to the present invention is not limited to the cache table of six entries as shown in FIG. 3, and the number of entries can be arbitrarily changed. is there.

As described above, the cache table stored in the cache table 201 has a cache table entry number for each entry, similarly to the above-described routing table.

Next, the cache search processor 9 searches the cache table stored in the cache table 201 for the destination IP address of the packet, and determines the destination interface.

At this time, in addition to rewriting the MAC header in accordance with the entry of the cache table, processing associated with the forwarding of the IP packet, such as updating the TTL (Time To Live) field and checksum in the IP header, is performed. The data is transferred to the destination interface by the unit 4.

If the destination IP address of the packet does not exist in the cache table 201 as a result of the search by the cache search processing unit 9, the cache search processing unit 9 transfers this packet to the main control unit 2.

Here, the difference between the method of searching the routing table 101 performed by the forwarding processing unit 5 and the method of searching the cache table 201 performed by the cache search processing unit 9 will be described.

Each entry stored in the routing table 101 describes a network address and a net mask as a destination IP address. When determining the destination interface, the destination IP of the received packet
The address is masked by the netmask of each entry, the masked value is compared with the network address, and a match is regarded as a hit. Further, this is repeated for all entries, and it is assumed that a hit has been made to the one having the largest mask bit length. This search method is called Longest Match.

On the other hand, with respect to the search of the cache table 201, each entry has a destination IP address as
The address of the host is described instead of the address of the network.

Therefore, when determining the destination interface, the destination IP address of the received packet is compared with the address of the entry, and a match is regarded as a hit. In this case, in the routing table 101, the IP address corresponding to the entry of the same network address and netmask is divided into individual entries in the cache table 201, but it is not necessary to perform Longest Match, so that a high-speed search can be realized. .

Next, the cache management unit 7 registers the entry in the cache table 201 by receiving the cache registration request from the forwarding processing unit 6.

The cache management unit 7 also stores data (hereinafter, referred to as a “relationship”) indicating the correspondence between the routing table entry number of the entry hit on the routing table 101 and the cache entry number of the entry registered in the cache table 201 at that time. A cache management table is generated and output to the cache management table 301.

FIG. 4 shows an example of the relationship between the cache entry number stored in the cache management table 301 shown in FIG. 1 and the routing entry number. However, the present invention is not limited to the relationship shown in FIG. 4, and any other relationship can be stored in the cache management table 301.

As described above, the routing table 10
1 stores an entry for a network address and a netmask, and the cache table 201 stores an entry for a host address.
A plurality of cache table entry numbers correspond to one routing table entry number.

Next, the routing table 101 is processed by the processing of the routing protocol by the protocol processing unit 5.
The operation performed when the entry stored in the entry is deleted or the content of the entry is changed will be described.

When an entry stored in the routing table 101 is deleted or the content of the entry is changed by the processing of the routing protocol of the protocol processing unit 5, a cache generated with reference to the entry is generated. The cache entry stored in the table 201 must be deleted immediately.

Therefore, the protocol processing unit 5 transmits a cache deletion request including the routing table entry number to the cache management unit 7.

The cache management unit 7 that has received the deletion request obtains a cache table entry number for the routing table entry number based on the data stored in the cache management table 301. And
The entry of the cache table 201 is deleted based on the obtained cache table entry number.

Next, the operation of the embodiment of the router according to the present invention shown in FIG. 1 will be described in more detail. Further, the following description of the operation also serves as the description of an embodiment of the transmission route setting method according to the present invention.

First, the IP address received by the interface unit 32 by the router device 1 shown in FIG.
Consider the case where a packet destined for aa1 is transferred.

Here, based on the control of the protocol processing unit 5, it is assumed that an entry of the network address aaa0 and the netmask 255.255.255.0 exists on the routing table 101 as shown in FIG.

When the packet destined for the IP address aaa1 passes through the router 1 for the first time, there is no entry for aaa1 in the cache table 201.

Therefore, this packet is transmitted to the switch unit 4
Is transferred from the interface unit 32 to the main control unit 2 via The forwarding processing unit 6 of the main control unit 2 searches the routing table 101 for the destination address of the packet by Longest Match.

Since the routing table stored in the routing table 101 is as shown in FIG. 2, the network address aaa0, the netmask
It will hit the entry of 255.255.255.0.

Then, the forwarding processing unit 6 adds a MAC header according to the entry, determines a transmission destination interface number, and transfers it to the interface unit 31. At the same time, the forwarding processing unit 6 sends a cache entry registration request to the cache management unit 7.

The cache entry registration request sent to the cache management unit 7 contains the IP address of the destination host, the value of the MAC header, the destination interface number, and the routing table number.

The cache management unit 7 which has received the cache entry registration request inputs the cache entry registration request with respect to the destination IP address.
The value of the MAC header and the destination interface number are registered in the cache table 201 as shown in FIG.
Further, as shown in FIG. 4, the cache management unit 7 registers the hit routing table entry number and the cache entry number of the generated cache entry in the cache management table 301.

Therefore, as shown in FIG. 4, the destination IP address aa which hits the entry of the network address aaa0 and the netmask 255.255.255.0
By forwarding the packets addressed to a.2 and aaa3, a plurality of cache entry numbers are registered in the cache management table 301 with respect to the routing table entry numbers.

Next, the operation when the entry on the routing table is deleted by the protocol processing unit 5 will be described. However, as entries to be deleted, network address aaa0, netmask 25
The case where 5.255.255.0 is deleted will be described as an example.

In this case, the protocol processing unit 5 transmits a cache entry deletion request to the cache management unit 7.
The cache entry deletion request includes the routing table entry number.

The cache management unit 7 refers to the routing table entry number No. 101 shown in FIG. 4 from the cache management table 301 and sets the generated cache entry number to the cache entry number No. 201,2.
Since these entries are found to be 04 and 205, these entries are deleted from the cache table 201.

Therefore, according to the router device 1 shown in FIG. 1, even when an entry of the cache table is deleted from the cache table 201, the routing entry number and the cache entry number stored in the cache management table 301 are deleted. The entry in the cache table 201 can be deleted on the basis of the correspondence with the above, so that the deletion can be realized at high speed with a low load.

[0114]

As is apparent from the above description, according to the present invention, all the contents of the cache table are changed with respect to the change including the deletion of the routing table as in the conventional router and the method of setting the transmission route. Correspondence between the routing entry number stored in the cache management table means and the cache entry number without performing a search process such as applying the mask of the deleted routing table entry to the entry and comparing it with the network address. It is possible to provide a router device and a transmission route setting method capable of deleting entries stored in the cache table means at high speed based on the relationship.

Further, the deletion of the entry stored in the cache table means can be performed based on the correspondence between the routing entry number stored in the cache management table means and the cache entry number. It is possible to provide a router device and a transmission route setting method capable of remarkably reducing the load of deleting a cache table due to a change including the above.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of a router device according to the present invention.

FIG. 2 is a diagram showing an example of a routing table stored in the router device shown in FIG.

FIG. 3 is a diagram illustrating an example of a cache table stored in the router device illustrated in FIG. 1;

4 is a diagram illustrating an example of a correspondence relationship between a routing entry number and a cache entry number stored in the router device illustrated in FIG. 1;

FIG. 5 is a block diagram showing a configuration of a conventional router device.

6 is a diagram showing an example of a routing table stored in the router device shown in FIG.

FIG. 7 is a diagram showing an example of a cache table stored by the router device shown in FIG.

[Explanation of symbols]

 Reference Signs List 1 router device 2 main control unit 4 switch unit 5 protocol processing unit 6 forwarding processing unit 7 cache management unit 8 physical termination unit 9 cache search processing unit 31, 32, 33 interface unit 101 routing table 201 cache table 301 cache management table

Claims (32)

[Claims] 1. A router device for determining a data transmission route when interconnecting networks, a network address as an IP address representing a destination network, and a next as an IP address of a next transfer destination router device with respect to a netmask. A routing table means (101) for storing a hop address and a transmission interface number; and a link layer (MA) as an IP address of a destination host.
C header) information and a transmission interface number are stored therein. A routing entry number is assigned to each entry of the routing table means, and a cache entry is assigned to each entry of the cache table means. A router device comprising a cache management table means (301) for storing a number indicating the correspondence between the routing entry number and the cache entry number. 2. Receiving a cache registration request to the cache table means, an entry is registered in the cache table means, the cache entry number of the entry registered in the cache table means, and Cache management means for generating data representing the correspondence between the hit entry and the routing entry number and outputting the data to the cache management table means
The router device according to claim 1, further comprising (7). 3. The cache management means has a routing entry number when an entry in the routing table means is deleted, when the contents of the entry in the routing table means are changed, or when another routing protocol is processed. 3. The router device according to claim 2, further comprising a protocol processing means (5) for outputting a deletion request including the following. 4. When the cache management unit outputs a deletion request including the routing entry number, the cache management unit refers to data stored in the cache management table unit, and specifies a routing entry included in the deletion request. 4. The router device according to claim 3, wherein a cache entry number corresponding to the number is obtained, and the entry stored in the cache table means is deleted based on the obtained cache entry number. 5. The router according to claim 1, further comprising forwarding processing means for performing forwarding processing on a received packet addressed to the address of the host. 6. The forwarding processing means, wherein the forwarding processing is performed by referring to a host address stored in the cache table means and when a destination interface means cannot be determined. Item 6. The router device according to item 5. 7. The forwarding processing means searches the received packet for the routing table means, and determines a next hop address for a destination IP address of an IP packet and a transmission destination interface number. Claim 5 or 6
2. The router device according to 1. 8. A search of said routing table means by said forwarding processing means, wherein a destination IP address of a received packet is masked by a netmask of all entries stored in said routing table means, and the value after masking is obtained. 8. The router device according to claim 7, wherein the comparison is performed with a network address, and among the matched addresses, the one having the largest mask bit length is regarded as a hit. 9. The TTL (Time To Live) in the IP header,
e) Field and checksum updates and other IP
Header processing associated with packet forwarding, and E
9. The router device according to claim 5, wherein a link layer process including addition of a MAC header of the Ethernet is performed. 10. When the forwarding processing means cannot determine a destination interface means for the received packet by referring to a host address stored in the cache table means, the forwarding processing means 10. The router device according to claim 5, wherein the router device outputs an entry registration request. 11. The router device comprises: a main control means (2) comprising the routing table means and the cache management table means; and at least one comprising the cache table means.
The router device according to any one of claims 1 to 10, further comprising the above interface means (31, 32, 33). 12. The main control means and the at least one
The router device according to claim 11, further comprising switch means (4) for connecting each of said interface means. 13. The communication device according to claim 1, wherein the interface means includes an Ethernet and an asynchronous transfer mode (ATM: A
Synchronous Transfer Mod
13. The router device according to claim 11, wherein the router device is configured by at least one of e). 14. The I of the destination host of the received packet.
14. The router device according to claim 1, further comprising a cache search processing unit (9) for searching a P address from the cache table unit and determining an interface unit to transmit. 15. The cache search processing means,
The search of the cache table means is performed by comparing an IP address of a destination host of a received packet with an entry of the cache table means, and considering a match as a hit. 15. The router device according to 14. 16. With a routing entry number,
Routing table means for storing a network address as an IP address representing a destination network, a next hop address as an IP address of a next transfer destination router device with respect to a netmask, and a transmission interface number; A cache table storing the address of the host; and a cache management table storing data representing a correspondence between the routing entry number and the cache entry number. The cache table is stored in the cache management table. A router that deletes an entry stored in the cache table at a high speed based on the data representing the correspondence. 17. A method for setting a data transmission route when interconnecting networks, comprising: a network address as an IP address representing a destination network, and a next hop address as an IP address of a next transfer destination router device with respect to a netmask. And a routing table storing the transmission interface number in a routing table means, and a link layer (MA) as an IP address of a destination host.
A cache table storing information of the C header) and a transmission interface number in a cache table means, wherein a routing entry number is assigned to each entry stored in the routing table means, and stored in the cache table means. And a cache management table storing step of storing data representing the correspondence between the routing entry number and the cache entry number in a cache management table means, in addition to a cache entry number assigned to each of the entries. How to set the transmission route to be used. 18. Receiving a cache registration request to the cache table means, an entry is registered in the cache table means, the cache entry number of the entry registered in the cache table means, and 18. The transmission route setting method according to claim 17, further comprising a cache management step of generating data representing a correspondence relationship between a hit entry and the routing entry number and outputting the data to the cache management table means. 19. When the entry of the routing table means is deleted, when the contents of the entry of the routing table means are changed, or when another routing protocol is processed, a routing entry number is added to the cache management step. 19. The transmission route setting method according to claim 18, further comprising a protocol processing step of outputting a deletion request including: 20. In the cache management step, when a deletion request including the routing entry number is output, a routing entry included in the deletion request is referred to by referring to data stored in the cache management table means. 20. The transmission route setting method according to claim 19, wherein a cache entry number corresponding to the number is obtained, and the entry stored in the cache table storing step is deleted based on the obtained cache entry number. 21. The transmission route setting method according to claim 17, further comprising a forwarding process for performing a forwarding process on a received packet addressed to the host address. 22. The forwarding process, wherein the forwarding process is performed by referring to the host address stored in the cache table storing process and determining the destination interface means. The method for setting a transmission route according to claim 21. 23. The forwarding processing step, for the received packet, searches the contents stored in the routing table means in the routing table storing step, a next hop address corresponding to a destination IP address of the IP packet, and a transmission destination 23. The method according to claim 21, wherein an interface number is determined. 24. The routing table search in the forwarding step, wherein a destination IP address of the received packet is masked by a netmask of all entries stored in the routing table, and a value after the masking is performed. 24. The transmission route setting method according to claim 23, wherein the transmission route setting is performed by comparing the address with a network address, and assuming that the bit having the largest mask bit length among the matched addresses is a hit. 25. The forwarding process, comprising: TTL (Time To Live) in an IP header.
e) Field and checksum updates and other IP
Header processing associated with packet forwarding, and E
25. The transmission route setting method according to claim 21, wherein a link layer process including addition of a MAC header of the Ethernet is performed. 26. If the forwarding processing step fails to determine the destination interface means for the received packet with reference to the host address stored in the cache table storing step, the cache managing step 26. The transmission route setting method according to claim 21, wherein an entry registration request is output to the communication route. 27. A method of setting a transmission route, comprising: a main control step including the routing table storing step and the cache management table storing step; and at least one interface means including the cache table storing step. 18. An interface step for transmitting data.
27. The method for setting a transmission route according to any one of claims to 26. 28. The apparatus according to claim 27, further comprising a switch step of inputting / outputting data between said main control step and said at least one interface step.
How to set the described transmission route. 29. The interface means through which data is transmitted in the interface step includes an Ethernet (registered trademark) and an asynchronous transfer mode (ATM: Asynchronous Transfer).
29. The method of setting a transmission route according to claim 27, wherein the method is configured by at least one of (r Mode). 30. The I of the destination host of the received packet.
30. The transmission route according to claim 17, further comprising a cache search processing step of searching for a P address from contents stored in the cache table storage step and determining an interface unit to transmit. How to set. 31. In the cache search process, the search of the cache table means compares an IP address of a destination host of a received packet with an entry stored in the cache table means, and hits a match if the IP address is matched. 31. The method for setting a transmission route according to claim 30, wherein the setting is performed by assuming that the transmission route has been performed. 32. With a routing entry number,
A routing table storing step of storing a network address as an IP address representing a destination network, a next hop address as an IP address of a next transfer destination router device with respect to a netmask, and a transmission interface number; A cache table storing step of storing a host address; and a cache management table storing step of storing data representing a correspondence between the routing entry number and the cache entry number. A method for setting a transmission route, wherein the entry stored in the cache table storing step is deleted at a high speed based on the stored data.