JP2000354061A - Retrieval device for connection information - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the retrieval frequency of connection information by caching autonomously the connection ID of a packet that is precedently received and a pointer set to the connection information for every logical channel. SOLUTION: When a logical channel number and a connection ID are notified by a packet receiving part, a processor part 11 starts a connection information retrieving part 19. The part 19 outputs the logical channel number and the connection ID to a cache part 20. The part 20 compares the data cached with the connection ID used as a key with a cache information corresponding to the logical channel number. If the connection ID matches with the cache information, a pointer is outputted to a connection information table 21. If no matching is confirmed between the connection ID and the cache information, a NULL pointer is outputted to the table 21. Thus, the retrieval frequency of the connection information can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a connection information search device, and more particularly to a connection information search device in packet communication.

[0002]

2. Description of the Related Art Conventionally, in packet communication, a packet switch searches a connection information table managed based on a destination of a packet every time a packet arrives, and determines an output port of the packet.

In such a case, if the number of connection managements increases, it takes time to search the management table and the packet throughput is reduced. The search speed was improved.

[0004]

However, in the method of collectively caching connection information, it is necessary to search for cached information. Therefore, when a cache miss occurs, all connection information is searched in addition to the cache search. , And an increase in the processing amount was unavoidable.

Furthermore, when a cache miss occurs, it is necessary to register the search result in the cache. Therefore, if the destination of the received packet is discontinuous, the hit rate to the cache is deteriorated and the throughput is reduced. Will be.

It is an object of the present invention to provide a connection information search device capable of reducing the number of times connection information is searched.

[0007]

To achieve the above object, a connection information retrieval apparatus according to the present invention retrieves a connection information table managed based on a destination of a packet every time a packet arrives. The apparatus is characterized by autonomously caching a connection ID and a pointer to connection information of a previously received packet for each logical channel.

[0010] With the above structure, in a connection information search device that searches a connection information table managed based on a destination of a packet every time a packet arrives, a connection ID and a connection of a previously received packet for each logical channel are provided. The pointer to the information
Cached autonomously. As a result, the number of connection information searches can be reduced.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a packet switch having a connection information search device according to an embodiment of the present invention. FIG. 2 is an explanatory diagram showing an example of the data structure, and FIG. 3 is an explanatory diagram showing another example of the data structure.

As shown in FIG. 1, a packet switch 10
Is a processor unit (connection information search device) 11,
The packet receiving unit 12 includes a packet receiving unit 12, a buffer unit 13, and a packet transmitting unit 14. The packet receiving unit 12 includes a plurality of terminating units 15 (15-1, 15-2,..., 15-n) and a received packet managing unit 16 have.

In the packet switch 10, a packet received from the receiving terminal or the receiving device 17 is received by the packet receiving unit 12. Specifically, the termination unit 15 extracts a packet including the connection ID and the transmission data from the transmission data as shown in the data structure of FIG.

The termination unit 15 sends the received packet and the identification number (logical channel number) of the logical channel of the packet to the received packet management unit 16 as shown in the data structure of FIG.

The logical channel is a logical connection line corresponding to the receiving terminal or the transmitting device or the remote devices 17 and 18 on a one-to-one basis. The logical channel number is uniquely determined in the device.

The packet receiving section 12 stores the packet data in the buffer section 13 upon receiving the packet, and notifies the processor section 11 of the logical channel number together with the connection ID in the packet data. Processor unit 11
Receives the connection ID and the logical channel number, and searches the connection information of the received packet based on the data. In the search processing, the cache device of the present invention is used.

The processor unit 11 acquires the path information of the packet from the retrieved connection information, and requests the packet transmitting unit 14 to transmit the corresponding packet.
The packet transmitting unit 14 transmits the corresponding packet to the opposite terminal or device 18 on the transmitting side in response to the transmission request.

FIG. 4 is a block diagram showing the configuration of the connection information search device of FIG. As shown in FIG. 4, the processor unit 11 includes a connection information search unit 19, a cache unit 20, and a connection information table 21.

In response to the notification of the packet information (logical channel number, connection ID) from the packet receiving unit 12, the processor unit 11
Start

The connection information search unit 19 accesses the cache unit 20, searches for a pointer of connection information at the time of a cache miss in the cache unit 20, and accesses the connection information table 21.

The cache unit 20 outputs cache information in response to access from the connection information search unit 19. When a cache miss occurs, the connection information pointer and the cache missed connection ID are both stored in the cache area of the logical channel where the cache miss occurred.

This cache processing is performed by inputting a connection information access display signal. The connection information access indication signal is sent to the connection information search unit 19.
Is output when read access is performed to the connection information table 21. The connection information table 21 stores path information, maintenance information, and the like for a unique connection in the device.

The packet receiving unit 12 notifies the connection information retrieving unit 19 of packet reception processing and packet information (logical channel number, connection ID).

FIG. 5 is a diagram showing the relationship between the data held by the cache unit and the data held by the connection information table. As shown in FIG. 5, the cache data for each logical channel of the cache unit 20 is stored in the connection information table 2.
1 and pointer to connection information in connection 1
Have D. The connection information table 21 is a table having information on all connections, and has path information and maintenance information for each connection.

Next, the operation of the connection information search device 10 having the above configuration will be described. As shown in FIG. 4, first, when the logical channel number and the connection ID are notified by the packet receiving unit 12, the processor unit 11 starts the connection information search unit 19.

The connection information search unit 19 outputs the logical channel number and the connection ID to the cache unit 20. The cache unit 20 compares the cached data corresponding to the logical channel number with the cached data using the connection ID as a key.

At this time, if the connection ID matches the cache information, a pointer to the connection information table 21 is output. If they do not match, the output is NUL
It becomes an L pointer.

Hereinafter, the case of a cache hit and the case of a cache miss will be described separately.

FIG. 6 is a timing chart showing the operation when a cache hit occurs. As shown in FIG.
At timing T1, the logical channel number of the received packet and the connection ID of the received packet are output from the connection information search unit 19 to the cache unit 20.

Between the timings T1 and T2, the cache unit 20 makes a comparison with the cache information. In the case of a cache hit, the connection information of the received packet is output as a pointer in the connection information table 21. At this time, the operation of the cache unit 20 ends.

In the connection information search unit 19, the pointer to the read connection information table 21 is set to N.
If it is not ULL, the effective address of the connection information corresponding to the timing T2 to T3 is calculated.

At a timing T3, an address to the connection information table 21 is output, and reading is performed to the connection information table 21. At timing T4, the connection information is read, and the search processing of the connection information ends.

FIG. 7 is a timing chart showing the operation when a cache miss occurs. Access to the cache unit 20 is the same as that described above, and will not be described.

As shown in FIG. 7, timings T5 to T6
In the case of a cache miss as a result of the comparison in the cache unit 20 during this time, the pointer to the connection information table 21 is set as a NULL pointer as the connection information search unit 1
9 is output. At this time, the operation of the cache unit 20 does not end but enters a standby state.

Next, in the connection information search unit 19,
Since the read pointer of the connection information table 21 is a NULL pointer, the timings T6 to T7
And finds the connection information pointer. Further, the effective address of the corresponding connection information is obtained.

At a timing T7, an address to the connection information table 21 is output, and reading to the connection information table 21 is performed. Also, between timings T7 and T8, the cache unit 20 receives the connection information access indication signal and returns from the standby state.

Then, the address of the connection information table 21 is read, and a pointer of the connection information table 21 is calculated. The cache unit 20 stores the calculated pointer together with the connection ID of the cache miss,
It is stored as cache data of the logical channel for which a cache miss occurred.

At timing T8, the connection information search section 19 reads out the connection information, and the search processing for connection information ends.

The connection information search of the packet by the processor unit (connection information search device) 11
The above series of operations are performed serially.

As described above, according to the present invention, the connection information search device autonomously caches the connection ID of the previously received packet and the pointer to the connection information for each logical channel, thereby searching for the connection information. The number of times can be reduced. That is, in the processor unit 11 of the packet switch 10,
The connection information of the received packet can be searched.

The connection information search unit 19 can omit the search processing by reading the pointer to the cached connection information from the cache unit 20. In the case of a cache miss, the cache unit 20 receives a connection information access indication signal
It autonomously acquires the connection information pointer of the connection for which a cache miss occurred.

As a result, since the cache unit 20 monitors the read access to the connection information table by the connection information access indication signal, the autonomous hardware caching operation becomes possible.

Also, by hardware autonomous caching,
Since the pointer can be cached on the connection in parallel with the reading of the connection information, the processing time of re-caching due to a cache miss can be reduced.

Further, since connection information is cached for each logical channel, the cache hit rate is increased, and the number of times connection information is searched can be reduced.

Further, by caching the pointer to the connection information instead of the connection information itself, the mismatch between the cached connection information and the connection information required by the packet can be reduced.

[0045]

As described above, according to the present invention, in a connection information retrieval apparatus which retrieves a connection information table managed based on a packet destination every time a packet arrives, a connection information table which has been received last time for each logical channel is obtained. Since the connection ID of the packet and the pointer to the connection information of the packet are autonomously cached, a hard autonomous caching operation becomes possible, and the processing time of re-caching due to a cache miss can be reduced.

Also, by caching for each logical channel, the number of times connection information is searched can be reduced, and inconsistency between the cached connection information and the connection information requested by the packet can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a packet switch having a connection information search device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating an example of a data structure.

FIG. 3 is an explanatory diagram showing another example of the data structure.

FIG. 4 is a block diagram illustrating a configuration of a connection information search device of FIG. 1;

FIG. 5 is a diagram illustrating a relationship between data of a cache unit and data of a connection information table.

FIG. 6 is a timing chart showing an operation when a cache hit occurs.

FIG. 7 is a timing chart showing an operation at the time of a cache miss.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Packet switch 11 Processor part 12 Packet receiving part 13 Buffer part 14 Packet transmitting part 15 Termination part 16 Received packet management part 17, 18 Opposite terminal or opposing device on the receiving side 19 Connection information search part 20 Cache part 21 Connection information table

Claims (6)

[Claims] 1. A connection information retrieval apparatus for retrieving a connection information table managed based on a destination of a packet every time a packet arrives, comprising: for each logical channel, a connection ID of a previously received packet and a pointer to connection information. And a connection information retrieval apparatus characterized by autonomously caching. 2. The connection information search device according to claim 1, wherein a search process is omitted by reading a pointer to the cached connection information. 3. The connection information search device according to claim 1, wherein in the case of a cache miss, a connection information pointer of the connection for which the cache miss has occurred is autonomously obtained by a connection information access indication signal. . 4. A cache unit for outputting cache information, and in the case of a cache miss, a cache unit for storing both a connection information pointer and a cache missed connection ID in a cache area of a logical channel in which a cache miss has occurred. A connection information table for storing path information, maintenance information, and the like for a new connection; a connection information search unit for accessing the cache unit, searching for a connection information pointer upon a cache miss, and accessing the connection information table The connection information search device according to any one of claims 1 to 3, further comprising: 5. The cache process is performed by inputting a connection information access display signal, and the connection information access display signal is output when the connection information search unit performs read access to the connection information table. The connection information search device according to claim 4, wherein: 6. A processor unit functioning as the connection information search device according to claim 1, a packet receiving unit for receiving a packet from a remote terminal or a remote device on the receiving side, and storing packet data. A packet switch comprising: a buffer unit; and a packet transmitting unit that receives a transmission request and transmits a corresponding packet to a transmitting-side opposing terminal or an opposing device.