KR20030018269A - Apparatus of IP lookup using cache forwarding table in router system, its method - Google Patents

Abstract

PURPOSE: An apparatus and a method for controlling Internet protocol address lookup by using a cache forwarding table in a router system are provided to establish identical IP(Internet Protocol) address combination from entire forwarding table lookup, and to perform lookup for one IP packet in the cache forwarding table and the entire forwarding table at the same time, so as to obtain a lookup result quickly upon cache hit. CONSTITUTION: An IP header processor(201) checks an IP header in an IP packet flowing through a forwarding engine in a router, to extract an IP address, TCP(Transmission Control Protocol) port information and connector information. An IP header cache controller(202) configures an entry based on information in the extracted IP header, to perform a lookup operation according to cache information. An IP address cache information storing unit(203) stores information corresponding to a recently matched IP packet in entire forwarding lookup under the control of the IP header cache controller(202). A cache label information storing unit(204) stores corresponding output packet information when one cache entry stored in the IP address cache information storing unit(203) under the control of the IP header cache controller(202). A lookup controller(205) generates a lookup control signal using corresponding IP header information when cache miss is generated for the IP header provided from the IP header cache controller(202) to acquire a lookup result, and delivers an acquired result to the IP header cache controller(202). An entire forwarding storing unit(206) provides forwarding information to the next hop of the IP packet and a lookup engine function under the control of the lookup controller(205). And a forwarding label information storing unit(207) stores output packet information corresponding to an entry when the entry is stored in the entire forwarding storing unit(206) under the control of the lookup controller(205).

Description

Apparatus of IP lookup using cache forwarding table in router system, its method}

The present invention relates to an Internet protocol (IP) address lookup control apparatus using a cache forwarding table in a router system and a method thereof. More particularly, the forwarding table configuration is doubled for a high-speed IP packet processing. The present invention relates to an Internet Protocol (IP) address lookup control apparatus using a cache forwarding table in a router system for simultaneously performing a lookup using a structure, and a method thereof and a computer-readable recording medium recording a program for implementing the method. .

In general, for the high speed processing of Internet packets, a conventional router system uses a software forwarding algorithm or hardware to look up an IP address through an entire forwarding table when an Internet Protocol packet is introduced. I'm using a search method.

1 is an exemplary configuration diagram of a device for controlling an Internet protocol (IP) address lookup using a conventional forwarding table.

As shown in FIG. 1, the Internet Protocol (IP) address lookup control apparatus includes an IP header processor 101, a lookup controller 102, an entire forwarding table 103, and a forwarding related table 104.

When the IP packet is introduced into the forwarding engine in the router, the IP header processor 101 extracts the IP address by checking the IP header and delivers the IP address to the lookup controller 102. The lookup controller 102 generates a lookup control signal using the IP address received from the IP header processor 101 and searches for a matching IP address among the IP address information previously stored in the entire forwarding table 103.

The lookup controller 102 accesses the forwarding related table 104 using the retrieved IP address, that is, the index of the lookup result, to obtain forwarding information.

Here, the entire forwarding table 103 performs a forwarding table to the next hop of the IP packet and a lookup engine function for performing layer 3 and layer 4 lookups. In addition, the forwarding related table 104 is an area having forwarding information for indexes of lookup results for layers 3 and 4 with respect to the forwarding table. The connection information related to forwarding to the next hop, routing physical port information, and layer 2 Information about the delivery protocol.

However, the conventional Internet protocol (IP) address lookup control apparatus uses a software search algorithm using the entire forwarding table, so that the search time is lengthened according to the number of forwarding entries. In the hardware method, the lookup preprocessing and the forwarding of the packet to be forwarded are performed. There was a problem that the time required for fetching related information deteriorates the forwarding capability of the IP packet.

Accordingly, the present invention has been proposed to solve the above problems, by building a matched IP address combination in the cache forwarding table in the entire forwarding table lookup to build a lookup for one IP packet in the cache forwarding table and the entire forwarding table. If the cache hit does not occur at the same time, it takes the same search time as the normal lookup, but if the cache hit is made, the Internet protocol (IP) address using the cache forwarding table in the router system to get the lookup result faster. It is an object of the present invention to provide a look-up control apparatus, a method thereof, and a computer-readable recording medium having recorded thereon a program for realizing the method.

1 is an exemplary configuration diagram of an Internet protocol (IP) address lookup control apparatus using a conventional forwarding table.

2 is a block diagram of an embodiment of an Internet protocol (IP) address lookup control apparatus using a cache forwarding table in a router system according to the present invention.

FIG. 3 is a detailed block diagram of an embodiment of the Internet Protocol (IP) header cache controller shown in FIG. 2; FIG.

4 is a flowchart illustrating a method of controlling an Internet protocol (IP) address lookup using a cache forwarding table in a router system according to the present invention.

<Explanation of symbols for the main parts of the drawings>

201: IP header controller 202: IP header cache controller

203: IP address cache table 204: Cache label information table

205: lookup controller 206: the entire forwarding table

207: Forwarding Label Table

The apparatus of the present invention for achieving the above object, in the router system in the Internet Protocol (IP) address lookup control using a cache forwarding table, IP header in the IP packet introduced through the forwarding engine in the router Means for processing an Internet Protocol (IP) header for extracting an IP address, TCP port information, and connector information; IP header cache control means for constructing an entry based on information in the IP header extracted from the Internet protocol header processing means to perform a lookup operation according to whether cache information is present; IP address cache information storage means for storing information corresponding to a recently matched IP packet in a total forwarding lookup under the control of the IP header cache control means; Cache label information storage means for storing output packet information corresponding to one cache entry stored in the IP address cache information storage means under the control of the IP header cache control means; When a cache miss for the provided IP header from the IP header cache control means occurs, a lookup control signal is generated using the corresponding IP header information to obtain a search result, and the acquired result is transmitted to the IP header cache control means. Lookup control means; Total forwarding storage means for performing a lookup engine function for performing a lookup and forwarding information of an IP packet to the next hop under the control of the lookup control means; And forwarding label information storage means for storing output packet information corresponding to the entry when the entry is stored in the entire forwarding information storage means under the control of the lookup control means.

On the other hand, the method of the present invention, in the Internet Protocol (IP) address lookup control method applied to the Internet Protocol (IP) address lookup control device, using the received IP header information, IP address, TCP port information and connector information as a key A first step of determining whether a cache is hit by performing a cache table lookup and a full forwarding table lookup; A second step of fetching an index indicating an address pointer when the cache is hit, and obtaining cache label information using the index information to change an IP header of an output IP packet; A third step of checking whether or not a match of the inspected IP lookup occurs when the cache hit does not occur as a result of the determination of the first step; In the third step, when the match occurrence of the IP lookup is confirmed, the cache table pointer is updated using the fetched label information, and the IP header of the output IP packet to be delivered to the next hop is changed to obtain IP address cache entry and cache label information. It is characterized in that it comprises a fourth step of adding.

On the other hand, the present invention, in order to control the Internet protocol (IP) address lookup, a cache table lookup and full forwarding, using the IP address, TCP port information and connector information, which are received IP header information, as a key in a router system having a processor. A first function of performing a table lookup to determine whether a cache is hit; A second function of fetching an index indicating an address pointer when the cache is hit, and obtaining cache label information using the index information to change an IP header of an output IP packet; A third function of checking whether or not a match of the inspected IP lookup occurs if the cache hit does not occur, as a result of the determination of the first function; In the third function, if the match occurrence of the IP lookup is confirmed, the cache table pointer is updated using the fetched label information, and the IP header of the output IP packet to be delivered to the next hop is changed to obtain IP address cache entry and cache label information. A computer readable recording medium having recorded thereon a program for realizing an additional fourth function is provided.

The objects, features and advantages described above will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of an embodiment of an apparatus for controlling an Internet protocol (IP) address lookup using a cache forwarding table in a router system according to the present invention.

As shown in FIG. 2, the Internet Protocol (IP) address lookup control apparatus includes an IP header processor 201, an IP header cache controller 202, an IP address cache table 203, a cache label information table 204, Lookup controller 205 and full forwarding table 206.

The IP header processor 201 examines an IP header from an IP packet introduced through a forwarding engine in a router, extracts an IP address, TCP port information, and connector information, and delivers the IP packet to the IP header cache controller 202 along with the IP packet. . The IP header cache controller 202 configures a single entry by combining an IP sender address, a destination address, TCP port information, a receiving port information, and a connector information in the IP header received from the IP header processor 201 to form a perfect match. exact match) to the IP address cache table 203 to perform a lookup, and at the same time to the IP address information to the lookup control unit 205 to perform a lookup function for the entire forwarding table.

Therefore, the lookup using the whole forwarding table and the lookup by the cache forwarding table are performed in parallel.

That is, the IP header cache controller 202 transfers the IP header information as one comparison key to the IP address cache table 203 and searches whether there is a matching entry. At this time, the IP header cache controller 202 performs a cache index control and a cache miss control according to a cache hit or a cache miss from the IP address cache table 203.

First, in order to perform cache index control according to a cache hit, the IP header cache controller 202 patches an index indicating an address pointer at which a hit occurred in the IP address cache table 203, and stores the patched index information. Cache label information is obtained from the cache label information table.

On the other hand, the IP header cache controller 202 looks up the IP address information from the IP header processing unit 201 in the entire forwarding table by using the already delivered IP header information when a cache miss for the header information is generated from the lookup controller. Check the performance of the function. In this case, if the lookup is not finished, the terminal waits until the end of the lookup, and when the lookup is completed, the lookup match information is acquired from the entire forwarding table 206. The lookup controller 205 searches the entire forwarding table 206 to transfer the lookup matched information, that is, the corresponding forwarding table information to the IP address cache table 203, and stores the corresponding label information at the same time. Transfer it to the information table 204 and store it.

In this case, the entire forwarding table 206 performs a forwarding table to the next hop of the IP packet and a lookup engine function for performing layer 3 and layer 4 lookups. Also, the forwarding label table 207 is an area having forwarding information for indexes of lookup results for layer 3 and layer 4 with respect to the forwarding table. The connection information, routing physical port information, and layer 2 Transfer protocol information, and so on.

FIG. 3 is a detailed block diagram of an embodiment of the Internet protocol (IP) header cache controller shown in FIG.

As shown in FIG. 3, the Internet Protocol (IP) header cache controller includes an IP header information storage unit 301, an IP cache table access control unit 302, a cache label information table access control unit 303, and a cache table pointer management unit. It consists of 304.

Here, the IP header information storage unit 301 extracts and stores IP source address and destination address, TCP source port and destination port information, and connector information in case of ATM, from the received packet header, and stores this information in a lookup controller ( 205 and IP cache table access control unit 302, respectively.

The IP cache table access control unit 302 transfers the IP address, TCP port, and connector information received from the IP header information storage unit 301 to the IP address cache table 203 using a comparison key as a matching entry. Search for the existence

At this time, the IP cache table access control unit 302 performs cache index control and control according to cache miss according to cache hit or miss information from the IP address cache table 203.

The cache label information table access control unit 303 receives the index transmitted from the IP cache table access control unit 302, transfers the received index to the cache label information table 204, and fetches a label. In addition, the cache label information table access control unit 303 receives matched label information from the entire forwarding table from the lookup controller 205 when a cache miss occurs, and stores the received label information as cache label information. Passed to the table 204 to control the updating of table information. The cache table pointer manager 304 transmits pointer management information for registering an IP cache table to the IP cache table access control unit 320 and pointer management information for registering cache label table information to the cache label information table access control unit 303. Pass each one.

4 is a flowchart illustrating a method of controlling an Internet protocol (IP) address lookup using a cache forwarding table in a router system according to the present invention.

As shown in FIG. 4, first, the IP cache header controller 202 determines whether IP header information is received from the IP header processor 201 (401), and as a result of the determination in step 401, IP When the header information is received, the cache table lookup is performed using the IP header information, the IP address, the TCP port information, the connector information, and the like as a key, and at the same time, the entire forwarding table lookup function is performed (402). At this time, the cache table lookup is first performed to determine whether a cache hit is generated from the IP address cache table (403). As a result of the determination in step 403, when a cache hit of a cache table lookup occurs, the IP header cache controller 202 fetches an index indicating an address pointer of a hit in the cache label information table based on the retrieved index information ( In operation 404, cache label information is obtained using the index information obtained through the fetch.

After acquiring the label information, the forwarding function when the cache hit is performed by performing the IP header change function of the output IP packet to be delivered to the next hop is terminated (406).

On the other hand, when the cache hit of the cache table lookup does not occur, as a result of the determination in step 403, that is, when a cache miss occurs in the cache hit check, the IP lookup performed by the lookup controller 205 for the entire forwarding table is completed. In step 407, it is determined whether a match of the completed IP lookup occurs.

As a result of the determination in step 408, if a lookup match does not occur, the process returns to step 401 of determining whether to receive information of an IP header to receive the next information, and repeats the loop, and if a lookup match occurs In step 409, the label information of the forwarding label table 207 latched by the lookup control unit 205 is fetched.

The cache table pointer is updated using the fetched label information and the IP header of the output IP packet to be delivered to the next hop is changed (410), and the IP address cache entry is located at a location corresponding to the update of the cache table pointer. Add and add cache label information to the corresponding location at the same time (411). In this case, when all the regions of the cache table are used up, the oldest entry is deleted and the most recent cache entry is added.

The method of the present invention as described above may be implemented as a program and stored in a computer-readable recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.).

The present invention described above is not limited to the stated embodiments and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

In the present invention as described above, by matching IP address combinations in the entire forwarding table lookup in the cache forwarding table, a lookup for one IP packet is simultaneously performed on the cache forwarding table and the entire forwarding table, thereby preventing cache hits. In this case, it takes the same searching time as a normal lookup, but in the case of a cache hit, the lookup result can be obtained faster, thereby improving the forwarding capability of the IP packet.

Claims (8)

In the router system in the Internet Protocol (IP) address lookup control using a cache forwarding table, Internet protocol (IP) header processing means for inspecting an IP header in an IP packet introduced through a forwarding engine in a router to extract IP address, TCP port information, and connector information; IP header cache control means for constructing an entry based on information in the IP header extracted from the Internet protocol header processing means to perform a lookup operation according to whether cache information is present; IP address cache information storage means for storing information corresponding to a recently matched IP packet in a total forwarding lookup under the control of the IP header cache control means; Cache label information storage means for storing output packet information corresponding to one cache entry stored in the IP address cache information storage means under the control of the IP header cache control means; When a cache miss for the provided IP header from the IP header cache control means occurs, a lookup control signal is generated using the corresponding IP header information to obtain a search result, and the acquired result is transmitted to the IP header cache control means. Lookup control means; Total forwarding storage means for performing a lookup engine function for performing a lookup and forwarding information to the next hop of an IP packet by the control of the lookup control means; And Forwarding label information storage means for storing output packet information corresponding to the entry when the entry is stored in all forwarding information storage means by the control of the lookup control means. Internet Protocol (IP) address lookup control device comprising a. The method of claim 1, The IP address cache information storage means, An Internet Protocol (IP) address lookup control device comprising an IP address, TCP port information and received connection information. The method of claim 1, The forwarding label information storage means, An Internet Protocol (IP) address lookup control device, comprising: connection information, routing physical port information, and forwarding protocol information related to forwarding to a next hop area having forwarding information on an index of a lookup result. The method of claim 1, The IP header cache control means, IP header information storage means for storing the IP address, TCP port information and connector information extracted by the Internet protocol (IP) header processing means; By using the IP address, TCP port information, and the connector information stored in the IP header information storage means as one comparison key, cache index control and control according to cache miss are performed according to the presence or absence of a matching end previously stored in the IP address cache information storage means. IP cache information access control means for performing; Cache label information access control means for patching a label by cache index control delivered from said IP cache information access control means, and updating label information received from said lookup control means; And Cache information pointer management means for managing a pointer for IP cache information registration of the IP cache information access control means and cache label information registration of the cache label information access control means. Internet Protocol (IP) address lookup control device comprising a. In the Internet Protocol (IP) address lookup control method applied to the Internet Protocol (IP) address lookup control device, A first step of determining whether a cache is hit by performing a cache table lookup and a full forwarding table lookup using IP addresses, TCP port information, and connector information, which are received IP header information, as keys; A second step of fetching an index indicating an address pointer when the cache is hit, and obtaining cache label information using the index information to change an IP header of an output IP packet; A third step of checking whether completion of the IP lookup occurs when a cache hit does not occur as a result of the determination of the first step, and checking whether a match of the inspected IP lookup occurs; When the match occurrence of the IP lookup is confirmed in the third step, the cache table pointer is updated using the fetched label information, and the IP header of the output IP packet to be delivered to the next hop is changed to obtain IP address cache entry and cache label information. 4th step to add Internet protocol (IP) address lookup control method comprising a. The method of claim 5, The second step, A fifth step of fetching an index indicating a hit address pointer in the cache label information table based on the retrieved index information when a cache hit of the cache table lookup occurs; A sixth step of acquiring cache label information by using the index information obtained through the fetch; And Step 7 of performing an IP header change function of the output IP packet to be forwarded to the next hop Internet protocol (IP) address lookup control method comprising a. The method of claim 5, The fourth step, A fifth step of fetching the latched label information when a lookup match occurs; A sixth step of updating a cache table pointer using the fetched label information and changing an IP header of an output IP packet to be delivered to the next hop; A seventh step of adding IP address cache entry and cache label information to a location corresponding to the update of the cache information pointer; Internet protocol (IP) address lookup control method comprising a. In a router system with a processor to control an Internet Protocol (IP) address lookup, A first function of determining whether a cache is hit by performing a cache table lookup and a full forwarding table lookup using IP addresses, TCP port information, and connector information, which are received IP header information, as keys; A second function of fetching an index indicating an address pointer when the cache is hit, and obtaining cache label information using the index information to change an IP header of an output IP packet; A third function of checking whether or not a match of the inspected IP lookup occurs if the cache hit does not occur, as a result of the determination of the first function; In the third function, if the match occurrence of the IP lookup is confirmed, the cache table pointer is updated using the fetched label information, and the IP header of the output IP packet to be delivered to the next hop is changed to obtain IP address cache entry and cache label information. 4th function to add A computer-readable recording medium having recorded thereon a program for realizing this.