JP3409723B2 - Packet communication device and credit update method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet communication device and a credit updating method for performing packet communication based on credits, and particularly to a technique of embedding credits in a part of an information packet in credit control of packet communication based on credits (piggy). The present invention relates to a packet communication device, a communication line system, and a credit updating method suitable for realizing back credit.

[0002]

2. Description of the Related Art Recently, as a credit call service,
By dialing a member number and a personal identification number registered in advance in an exchange at the time of a call, a charge related to the call is charged to a pre-designated subscriber phone, and a cashless call service is provided from anywhere in the country.
In addition, by providing a credit-dedicated card, a service that reduces dial operations when using a credit-call service from a public phone or a pink phone is also provided. In addition, an international credit calling service is also provided, and recently,
Credit communication services are also provided, and services for transmitting communication data in packet format are also actually provided.

Regarding this international credit calling service,
IEEE (Institute of Electrical and Electrical)
csEngineers) 1284.4. Regarding this regulation, for example, in a credit-based packet communication system disclosed in Japanese Patent Laid-Open No. 9-135270, the number of "information" packets (information packets) that the receiving side can currently receive with respect to the transmitting side in advance (credit packet). The number of credits is transmitted as a special packet (instruction packet) having a format different from that of the information packet to provide the number of credits to the transmitting side.

Then, the transmitting side can continuously transmit the information packets within the maximum number of credits indicated by the receiving side.

The above-mentioned Japanese Laid-Open Patent Publication No. 9-135270 is intended to provide a credit number determination device suitable for use in a communication system, in which a terminal determines a type of a received packet, A means for buffering the received packet, a means for processing the received information packet according to the regulations of the communication protocol, a packet storage queue means for storing the received information packet,
When a credit number inquiry packet is received, a means for creating a response packet toward the transmission side line, a means for counting the number of received information packets passed to the upper layer, and a means for counting after sending the response packet are reset. There is disclosed a credit number determination device including means.

In the apparatus of FIG. 9 which realizes the above-mentioned packet communication system, the state of updating the credit with the command packet will be described with reference to FIG.

FIG. 9 is a functional block diagram showing a configuration example of a conventional packet transmitting / receiving apparatus. The conventional packet transmission / reception device includes a transmission line control unit 1, a transmission buffer 2, a credit update packet creation unit 3, an update packet number counting unit 4,
Counter subtraction unit 5, reception line control unit 6, reception buffer 7, response packet creation unit 8, reception packet type determination unit 9, information packet processing unit 10, reception packet storage queue 11, command packet processing unit 13, transmission credit count It includes a unit 14 and a transmission packet creation unit 16.

First, as an initial operation, when a connection request command packet is transferred from the transmission side P1 which has generated a connection request to the reception side P2, the reception side P2 returns the pre-reserved initial credit, and on the other hand, the transmission side. Also from P1 to the receiving side P2, the credit number of the information packet from the receiving side P2 to the transmitting side P1 is updated by the command packet, and the receiving side P2 transmits the command packet as its response.

The following will be described with reference to FIGS. 9 and 10. The transmission side P1 and the reception side P2 in FIG. 10 are the packet transmission / reception devices shown in FIG. 9, respectively, and the transmission line control unit 1 and the reception line control unit 6 are connected to each other.
Since the transmitting side P1 can transfer the information packet to the receiving side P2 by the amount of the initial credit, it transfers the information packet at any time. On the receiving side P2, the packet (reception packet 110) received by the reception line control unit 6 is stored in the reception buffer 7.

The received packet type discrimination unit 9 notifies the information packet processing unit 10 if the packet is an information packet, and notifies the instruction packet processing unit 13 if the packet is an instruction packet. The information packet processing unit 10 determines the storage state of the packet on the reception buffer 2 by the reception packet storage queue 11
Register with. The reception packet storage queue 11 notifies the packet counting unit 4 that the packet has been processed each time the upper layer reads the reception packet from the reception packet storage queue. The update packet number counting unit 4 counts up an internal counter each time a notification is received from the received packet storage queue 11, and notifies the credit update packet creation unit 3 if the result reaches the maximum value of the received packets. To do.

The credit update packet creation unit 3 creates a credit update command packet with the current count number in the transmission buffer 2 and notifies the counter subtraction unit 5 of the count number. The counter subtraction unit 5 subtracts the counter of the packet count unit 4 by the notified count number. When the transmission request from the upper layer is satisfied, the transmission packet creation unit 16 is completely asynchronous with the processing so far,
If the number of transmission credits of the transmission credit number counting unit 14 is not 0, 1 is subtracted and a transmission packet is created in the transmission buffer 2.

The transmission line control section 1 transmits the packets created in the transmission buffer 2 as a transmission packet 100 in the order of creation, without distinguishing between the command packet and the information packet. Further, the instruction packet processing unit 13 confirms whether the instruction packet is a credit update or a response packet to the credit update, and if the response packet is a response packet, recognizes that the credit update is normally completed, and issues a credit update instruction. If it is a packet, the updated credit number is notified to the transmission credit number counting unit 14 and further to the response packet creation unit 8. The transmission credit number counting unit 14 adds the notified count number to the transmission credit number, which is an internal counter. The response packet creation unit 8 creates a response command packet in the transmission buffer 2.

As described above, with respect to the IEEE1284.4 standard, in the credit-based packet communication method disclosed in, for example, Japanese Patent Laid-Open No. 9-135270, an instruction packet is always used to update the credit. The transfer load for this was a problem.

Therefore, in IEEE1284.4, which is one of credit-based packet communication systems, a method of embedding credit in a part of information packets to be transmitted to each other is defined in addition to the credit update by the above-mentioned command packet. It was The processing in this case is shown in FIG.
This will be described with reference to FIG.

First, as an initial operation, when a connection request command packet is transferred from the transmission side P1 having a connection request to the reception side P2, the reception side P2 responds to the transmission side P1 with the number of receivable credits as an initial credit. Command packet is transmitted. The transmitting side P1 can transfer the information packet to the receiving side P2 by the number of initial credits. However, when transferring the information packet to the receiving side P2, the information is transferred from the receiving side P2 to the transmitting side P1. The process of embedding the packet transfer credit in part of the information packet. The receiving side P2 analyzes and processes the information packet received from the transmitting side P1. However, since the packet embedded in the information packet can be transferred to the transmitting side P1, the response is converted into an information packet and transmitted. Credits for packet transfer from the side P1 to the receiving side P2 are embedded in a part of the information packet and transferred to the transmitting side P1.

[0016] As described above, the conventional method of embedding credit in a part of an information packet uses a method of passing the credit between the transmission of the information packet and the response thereof.

[0017]

However, the above-mentioned conventional technique has the following problems.

The first problem relates to IEEE1284.4, and in the credit-based packet communication method as disclosed in, for example, Japanese Patent Laid-Open No. 9-135270, credit is always updated by a dedicated packet (command packet). Therefore, the transfer load of the instruction packet for updating the credit number is applied for the credit update.

The second problem is that in the method of embedding a credit in a part of the information packet of the packet communication based on credit known by IEEE1284.4,
Since the functional operation of always responding to the transmission is used in the method of embedding the credit in a part of the information packet, the function must be such that it returns a response to the transmission of the other party. In other words, in the case of a function in which transmission and reception are processed at different timings, the timing at which credits must be given and the timing at which credits are updated are asynchronous, so the above-mentioned known In the method of embedding credit in a part of information packet of packet communication based on existing credit, credit cannot be embedded in a part of information packet.

An object of the present invention is to provide a technique for embedding credit information in a part of an information packet in credit-based packet communication control in the case where both transmissions are performed asynchronously (the timing of packet transfer of each is synchronized. If there is a request to update the number of credits, check whether there is an information packet waiting to be sent, and if the credit can be updated, embed the credit in a part of the information packet to credit the credit. The present invention provides a packet communication device and a credit updating method capable of reducing credit updating processing by an instruction packet and improving transfer efficiency by updating.

[0021]

SUMMARY OF THE INVENTION According to the present invention, in a packet communication device that performs packet communication by transmitting a credit indicating the number of receivable information packets to the other party, the credit is issued when a credit update request is made. Determination means for determining whether or not the credit can be updated, and if the determination means determines that the credit can be updated, an embedding means for embedding the credit in a part of the transmission waiting information packet and a transmission waiting
The counting means for counting the number of information packets and the credit
Create a command packet to be updated and measure the time.
And a counting means for measuring,
Referring to the number of transmission waiting information packets counted by the means
The credit is updated within the specified time measured by the time measuring means.
It is determined whether or not new information is available, and the information waiting to be sent is sent within the specified time.
If the number of bets increases and the credit can be updated,
At the time of stipulation, issuing a credit embedding instruction to the embedding means
Credit due to insufficient number of information packets waiting to be sent
If it is impossible to update the
It is characterized by giving a successful instruction .

[0022]

Further, the transmission means has a storage means for storing the transmission wait information packet, and the embedding means stores the transmission wait information stored in the storage means when the determination means determines that the credit can be updated. The feature is that credit is embedded in a part of the packet.

[0024]

Further, the packet communication device can be applied when any of the host device such as the host computer and the peripheral device such as the printer existing on the same communication line updates the credit with respect to the other party. Is characterized by.

Further, according to the present invention, in a credit update method in a packet communication device for performing packet communication by transmitting a credit indicating the number of receivable information packets to the other party, the credit is updated when a credit update request is made. And a step of embedding the credit in a part of the transmission waiting information packet when it is judged that the credit can be updated, and the number of transmission waiting information packets. Counting process to count
And create an instruction packet to update credits
And a time measuring step for measuring time,
The waiting information packet counted in the counting step is
The clock within the specified time counted in the timekeeping process.
Determine whether it is possible to update the ledger and send it within the specified time.
Credit waiting can be updated by increasing the number of waiting information packets
If not, give a credit embedding instruction to the embedding process.
The number of information packets waiting to be sent is insufficient within the specified time.
If the credit cannot be renewed, order the creation process
The feature is that a packet creation instruction is given .

[0027]

Further, there is a storing step for storing the transmission waiting information packet, and in the embedding step, the transmission waiting information stored in the storing step when it is judged in the judging step that the credit can be updated. The feature is that credit is embedded in a part of the packet.

[0029]

Further, the present credit updating method can be applied to the case where any one of a host device such as a host computer and a peripheral device such as a printer existing on the same communication line updates the credit to the other party. Is characterized by.

The packet communication device of the present invention is shown in FIG.
Further, referring to FIG. 8, in a packet communication device that performs packet communication by transmitting a credit indicating the number of receivable information packets to the other party, the credit is updated when a credit update request is made. Determination means (19 in FIG. 1) for determining whether the credit can be updated, and an embedding means for embedding the credit in a part of the transmission waiting information packet (FIG. 1) when the determination means determines that the credit can be updated. 17) and are provided.

Further, it is provided with counting means (15 in FIG. 1) for counting the number of transmission waiting information packets, and creating means (3 in FIG. 1) for creating a command packet for updating the credit,
The discriminating unit (19 in FIG. 1) discriminates whether or not the credit can be updated by referring to the number of transmission waiting information packets counted by the counting unit (15 in FIG. 1), and the credit can be updated. In this case, the embedding means (17 of FIG. 1) is instructed to embed a credit, and when the credit cannot be updated, the creation means (3 of FIG. 1) is instructed to create an instruction packet. .

Further, a storage means (18 in FIG. 1) for storing the transmission waiting information packet is provided, and the embedding means (17 in FIG. 1) updates the credit by the discrimination means (19 in FIG. 1). If it is determined that it is possible, the storage means (1 in FIG.
The control is performed so that the credit is embedded in a part of the transmission waiting information packet stored in 8).

Further, a time measuring means for measuring time (2 in FIG. 8)
0), the discriminating means (19 in FIG. 8) refers to the number of transmission waiting information packets counted by the counting means (15 in FIG. 8) and is timed by the time counting means (20 in FIG. 8). It is determined whether the credit can be updated within the specified time,
When the number of transmission waiting information packets increases and the credit can be updated, a credit embedding instruction is given to the embedding means (17 in FIG. 8), and the number of transmission waiting information packets is insufficient within the prescribed time. When the credit cannot be updated, the creating means (3 in FIG. 8) is controlled to give an instruction packet creating instruction.

[Operation] In the packet communication device of the present invention, for example, either the host computer or other upper device or the printer or other peripheral device on the same communication line needs to update the credit to the other party. Sometimes, if there is an information packet waiting to be sent, and if there is an information packet waiting to be sent and the credit can be updated, the credit is embedded in a part of the information packet and the credit cannot be updated. If so, the credit is updated by sending an instruction packet as before.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment] (1) Description of Configuration FIG. 1 is a functional block diagram showing a configuration example of a packet transmitting / receiving apparatus according to a first embodiment of the present invention.

The packet transmission / reception apparatus of the first embodiment of the present invention comprises a transmission line control unit 1, a transmission buffer 2, a credit update packet creation unit 3, an update packet number counting unit 4, a counter subtraction unit 5, and a reception line control unit. 6, reception buffer 7, response packet creation unit 8, reception packet type determination unit 9, information packet processing unit 10, reception packet storage queue 11, piggyback credit extraction unit 12, command packet processing unit 13, transmission credit number counting unit 14 , The transmission waiting packet number counting unit 15, the transmission packet creating unit 1
6, a piggyback credit embedding unit 17, a transmission waiting packet storage queue 18, and a credit update determination unit 19. In the figure, 100 is a transmission packet, 110 is a reception packet, 120 is an upper layer transmission, and 130 is an upper layer reception.

In FIG. 1, the same components as those shown in FIG. 9 are designated by the same reference numerals, and the description will be simplified or omitted.

The function of each unit of the packet transmitting / receiving apparatus will be described in detail. The receiving line control unit 6 stores the received packet in the receiving buffer 7 and advances the process to the receiving packet type discriminating unit 9. The reception packet type discrimination unit 9 refers to the reception buffer 7 to notify the instruction packet processing unit 13 if the received packet is an instruction packet for credit update, and to extract a piggyback credit if it is an information packet for normal processing. Notify the department 12. The piggyback credit extraction unit 12 extracts the credit embedded in the information packet, notifies the transmission credit count unit 14 of the number of credits, and advances the processing to the information packet processing unit 10.

The information packet processing unit 10 registers the storage state of the information packet in the reception buffer 2 in the reception packet storage queue 11. Received packet storage queue 11
Notifies the update packet number counting unit 4 every time the upper layer sequentially reads out the information of the received packet storage queue (every time when the upper layer receives 130 in the drawing). The update packet number counting unit 4 adds an internal counter by the notification, and when the counted value becomes equal to the maximum value of the queue, notifies the credit update determination unit 19 to make a credit update command packet.

The credit update determination unit 19 refers to the transmission waiting packet number counter 15 and determines whether or not the credit can be updated by piggyback credit (a determination method will be described later), and the credit is updated. Piggyback credit embedding unit 1 if possible
7, the process proceeds to the credit update packet creation unit 3 if the credit cannot be updated.

The credit update packet creation unit 3 includes the update packet number counting unit 4 to the credit update determination unit 19
Based on the instruction packet creation notification sent via
Send a command packet to update the number of credits Buffer 2
In addition, the counter subtraction unit 5 is notified and the update packet number counting unit 4 is cleared.

Piggyback credit embedding unit 17
Performs a packet operation on the transmission buffer 2 shown in the transmission waiting packet storage queue 18 and embeds the credit to be updated as piggyback (the embedding method will be described later), as well as the counter subtraction unit 5 as described later. It notifies and clears the update packet number counting unit 4.

On the other hand, if the command packet updates the credit, the command packet processing unit 13 notifies the transmission credit number counting unit 14 of the credit number, advances the process to the response packet creating unit 8 and receives the credit. If the command packet is a response packet, nothing is done. The response packet creation unit 8 creates an instruction packet indicating that the credit update is completed in the transmission buffer 2.

When the transmission information is sent from the upper layer (transmission of the upper layer indicated by 120 in the figure), the transmission packet creating section 16 refers to the transmission credit number counter 14,
If it is not 0, this is reduced by the number of packets to be created, and then the information is packetized and created in the transmission buffer 2, and at the same time, the number of packets to be created is notified to the transmission waiting packet number counter 15, and The storage state in the transmission buffer 2 is stored in the transmission waiting packet storage queue 18
Register with. Further, the transmission packet creation unit 16 does not perform the transmission process when the transmission credit counter 14 is 0.

(2) Description of Operation Next, the operation of the first embodiment of the present invention will be described with reference to FIGS.
This will be described in detail with reference to FIG. 7.

First, the credit update determination unit 19 described above.
2 for the determination method of the update process of the piggyback credit credit embedding unit 17,
This will be described in detail below with reference to FIG. FIG. 2 is a flowchart showing the processing of the credit update determination unit 19, and FIG. 3 is a flowchart showing the processing of the piggyback credit embedding unit 17.

Here, when the number of credits to be awarded is C0, this is Cp + Cp + ... + Cp + C2
(However, 1 <= C2 <= Cp; Cp = 1 maximum value of the number of credits that can be embedded in one information packet) (step S500). At this time, it is determined whether or not the number of transmission waiting information packets (denoted by n) counted by the transmission waiting packet number counting unit 15 satisfies n> = C1 + 1 (where C1 is the number of repeating Cp described above). Step S510). However, the code “1 <= C2” indicates that C2 is equal to 1 or greater than 1.

If the number of transmission waiting information packets does not satisfy the above equation, it is impossible to give credit by a method of embedding credit in a part of the transmission waiting information packet. A command packet for updating the received credit (step S530). When the number of transmission waiting information packets satisfies the above expression, credit can be given by a method of embedding credit in a part of the transmission waiting information packets, and therefore the process branches to the piggyback credit embedding unit 17 (step S520).

As shown in FIG. 3, the piggyback credit embedding unit 17 compares whether or not C1 is 0 (step S600). When C1 is not 0 (when C1 is 1), the transmission waiting information packet No. 0 to the transmission waiting information packet are stored in the transmission waiting packet storage queue 18 based on the stored information of the transmission waiting information packet in the transmission buffer 2. The piggyback credit up to No. C1-1 is Cp, and the piggyback credit of the transmission waiting information packet No. C1 is C2 (step S61).
0). When C1 = 0, the transmission waiting information packet No.
Only the piggyback credit of 0 is set as C2 (step S620).

As described above, if possible, by embedding the credit in a part of the transmission waiting information packet, the credit updating process can be performed without newly transmitting the command packet.

Next, an example of giving credits according to the first embodiment will be described in detail with reference to FIGS. In addition, in the first embodiment of the present invention, the maximum number of credits in which credits can be embedded in a part of the packet waiting to be transmitted is 255.

FIG. 4 is a time chart when the piggyback credit process is performed by one transmission waiting information packet. In FIG. 4, as an initial operation, when a connection request command packet is transferred from the transmission side P1 having a connection request to the reception side P2, the reception side P2 responds to the transmission side P1 with the number of receivable credits as an initial credit. Command packet as a packet (echo packet) of
On the other hand, the credit number of the information packet in the direction from the receiving side P2 to the transmitting side P1 is given by the command packet from the transmitting side P1 to the receiving side P2, and the receiving side P2 returns the command packet as the echo packet.

After that, the operation of the packet transmitting / receiving apparatus shown in FIG. 1 is performed. Since the transmitting side P1 can transfer the information packet to the receiving side P2 by the number of initial credits, the information packet is transferred at any time. Receiver P2
Then, the receiving line control unit 6 receives a packet (information packet) from the transmitting side P1. The received packet type discrimination unit 9
This is judged as an information packet, and the process branches to the piggyback credit extraction unit 12. The piggyback credit extraction unit 12 extracts 0 as the piggyback credit, notifies the transmission credit count unit 14, and advances the processing to the information packet processing unit 10.

The information packet processing unit 10 registers the storage state of the information packet on the reception buffer 7 in the reception packet storage queue 11. The upper layer sequentially processes the information packets based on the received packet storage queue 11,
On the other hand, the transmission information is passed from the upper layer to the transmission packet creation unit 16, and the transmission packet creation unit 16 packetizes the passed information into two packets. It was confirmed that it was 2 or more, but since it was 2 or more, it is subtracted by 2 and then the transmission information is packetized and stored in the transmission buffer 2, and at the same time, the counter is incremented by 2 in the transmission waiting packet number counting unit 15. reported.

At this point in time, packet transfer from the sending side P1 to the receiving side P2 is still in progress, and transmission from the receiving side P2 to the sending side P1 is not being performed. A little later than that, the count number of the update packet number counting unit 4 reached the maximum number of received packets (10 in FIG. 4), so the credit number (= 10) that needs to be updated is the credit update determination unit 19 2 performed the judgment process of FIG. 2, it was found that 255 × 0 +10 = 10 and 2> = 1 + 0 = 1 (updating can be done by one transmission waiting information packet), so it is possible to renew the credit by the piggyback credit. The determination is made, the processing is moved to the piggyback credit embedding unit 17, and the update packet number counting unit 5 is notified of the clearing of the update packet number.

Piggyback credit embedding unit 17
Is 1 (1 can be updated with one transmission waiting information packet) based on the determination processing of FIG. 3, so the piggyback credit of the transmission waiting information packet No. 0 is rewritten to 10.

Then, from the receiving side P2 to the transmitting side P1 this time.
The transmission process to S1 has started, and the transmission line control unit 1 has transmitted two information packets, but the first piggyback credit is 10. The reception line control unit 6 of the transmission side P1 receives this information packet, and the reception packet type determination unit 9 determines that it is an information packet. Therefore, the piggyback credit extraction unit 12 extracts 10 piggyback credits. , And is added to the transmission credit number counting unit 14, so that the transmission processing can be continued again.

FIG. 5 is a time chart when the piggyback credit process by one transmission waiting information packet is not successful. In FIG. 5, as the initial operation,
When the connection request command packet is transferred from the transmission side P1 where the connection request is generated to the reception side P2, the reception side P2 commands the transmission side P1 as a response packet (echo packet) with the receivable credit number as an initial credit. The packet number is transmitted in packets, and on the other hand, the number of credits of the information packet from the receiving side P2 to the transmitting side P1 is also given to the receiving side P2 by the command packet, and the receiving side P2 commands the echo packet. Returns the packet.

After that, the operation of the packet transmitting / receiving apparatus shown in FIG. 1 is performed. Since the transmitting side P1 can transfer the information packet to the receiving side P2 by the number of initial credits, the information packet is transferred at any time. Receiver P
In 2, the reception line control unit 6 receives a packet (information packet) from the transmission side P1. Received packet type discrimination unit 9
Judges that this is an information packet and branches the process to the piggyback credit extraction unit 12. The piggyback credit extraction unit 12 extracts 0 as the piggyback credit, notifies the transmission credit count unit 14, and advances the processing to the information packet processing unit 10.

The information packet processing unit 10 registers the storage state of the information packet on the reception buffer 7 in the reception packet storage queue 11. The upper layer sequentially processes the information packets based on the received packet storage queue 11, while the transmission information is passed to the transmission packet creation unit 16 from the upper layer, and the transmission packet creation unit 16 is delivered. Since the packetized information has a size of 2 packets, it was confirmed whether the transmission credit number counting unit 14 was 2 or more. However, since it was 2 or more, it was reduced by 2 and the transmission information was packetized in the transmission buffer 2. At the same time, the counter is set to 2 in the transmission waiting packet count section 15.
Notified to add.

At this point, the packet transfer from the transmitting side P1 to the receiving side P2 is still continuing, and the transmission from the receiving side P2 to the transmitting side P1 is not performed.

Then, from the receiving side P2 to the transmitting side P1 this time.
The transmission line control unit 1 has transmitted two information packets, but the piggyback credit is 0.
Is. After that, the information packet was transmitted from the transmitting side P1 to the receiving side P2 again, and the same processing was performed again.
As a result, since the count number of the packet number counting unit 4 has reached the maximum number of received packets (10 in FIG. 5), the credit update determination unit 19 of FIG. When the judgment process is performed, it is 255 × 0 + 10 = 10 and 0> = 1 + 0 = 1 (one transmission waiting information packet can be given, but there is no transmission waiting information packet), so the credit cannot be updated by piggyback credit. Then, the processing is moved to the credit update packet creation unit 3, and the update packet number counting unit 5 is notified that the update packet number is cleared.

As described above, in the state where there is no transmission waiting information packet, the credit is updated by the command packet as usual.

FIG. 6 is a time chart of piggyback credit processing by a plurality of transmission waiting information packets.
In FIG. 6, as an initial operation, when a connection request command packet is transferred from the side P1 that has generated a connection request to the reception side P2, the reception side P2 sends a response to the transmission side P1 with the number of receivable credits as the initial credit. The command packet is sent as a packet (echo packet), while the sending side P
From 1 to the receiving side P2, the credit number of the information packet from the receiving side P2 to the transmitting side P1 is given by the command packet, and the receiving side P2 returns the command packet as the echo packet.

After that, the operation of the packet transmitting / receiving apparatus shown in FIG. 1 is performed. Since the transmitting side P1 can transfer the information packet to the receiving side P2 by the number of initial credits, the information packet is transferred at any time. Receiver P2
Then, the receiving line control unit 6 receives a packet (information packet) from the transmitting side P1. The received packet type discrimination unit 9
This is judged as an information packet, and the process branches to the piggyback credit extraction unit 12. The piggyback credit extraction unit 12 extracts 0 as the piggyback credit, notifies the transmission credit count unit 14, and advances the processing to the information packet processing unit 10.

The information packet processing unit 10 registers the storage state of the information packet on the reception buffer 7 in the reception packet storage queue 11. The upper layer sequentially processes the information packets based on the received packet storage queue 11, while the transmission information is passed to the transmission packet creation unit 16 from the upper layer, and the transmission packet creation unit 16 is delivered. Since the packetized information has a size of 2 packets, it was confirmed whether the transmission credit number counting unit 14 was 2 or more. However, since it was 2 or more, it was reduced by 2 and the transmission information was packetized in the transmission buffer 2. At the same time, the counter is set to 2 in the transmission waiting packet count section 15.
Notified to add.

At this point in time, packet transfer from the sending side P1 to the receiving side P2 is still in progress, and transmission from the receiving side P2 to the sending side P1 is not being performed. A little later than that, the count number of the update packet number counting unit 4 became the maximum number of received packets (300 in FIG. 6).
When the credit update determination unit 19 performs the determination process of FIG. 2 from the number of credits (= 300) that need to be updated, it is 255 × 1 + 45 = 300 and 2> = 1 + 1 = 2 (awardable by two piggybacks) Therefore, it is determined that the credit can be updated by the piggyback credit, the process is moved to the piggyback credit embedding unit 17, and the update packet number counting unit 5 is notified that the update packet number is cleared.

Piggyback credit embedding unit 17
Is 2> 1 (which can be updated by two or more transmission waiting information packets) based on the judgment processing of FIG. 3, the piggyback credit of the transmission waiting information packet No. 0 is set to 255, and the transmission waiting information packet N is set.
The process of rewriting the piggyback credit of o.1 to 45 was performed.

Then, from the receiving side P2 to the transmitting side P1 this time.
The transmission line control unit 1 has transmitted two information packets, and the first piggyback credit is 255 and the second piggyback credit is 45. The receiving line control unit 6 of the transmitting side P1
This information packet is received, and the received packet type discrimination unit 9
Since it is determined to be an information packet, the piggyback credit extraction unit 12 determines that the first information packet is 2
From the 55th and 45th piggyback credits, 45 piggyback credits are extracted and added to the transmission credit number counting unit 14 (300 in total), so that the transmission processing can be continued again.

FIG. 7 is a time chart when the piggyback credit process using a plurality of transmission waiting information packets is not successful. In FIG. 7, as the initial operation,
When the connection request command packet is transferred from the transmission side P1 where the connection request is generated to the reception side P2, the reception side P2 commands the transmission side P1 as a response packet (echo packet) with the receivable credit number as an initial credit. The packet number is transmitted in packets, and on the other hand, the number of credits of the information packet from the receiving side P2 to the transmitting side P1 is also given to the receiving side P2 by the command packet, and the receiving side P2 commands the echo packet. Returns the packet.

After that, the operation of the packet transmitting / receiving apparatus shown in FIG. 1 is performed. Since the transmitting side P1 can transfer the information packet to the receiving side P2 by the number of initial credits, the information packet is transferred at any time. Receiver P
In 2, the reception line control unit 6 receives a packet (information packet) from the transmission side P1. Received packet type discrimination unit 9
Judges that this is an information packet and branches the process to the piggyback credit extraction unit 12. The piggyback credit extraction unit 12 extracts 0 as the piggyback credit, notifies the transmission credit count unit 14, and advances the processing to the information packet processing unit 10.

The information packet processing unit 10 registers the storage state of the information packet on the reception buffer 7 in the reception packet storage queue 11. The upper layer sequentially processes the information packets based on the received packet storage queue 11, while the transmission information is passed to the transmission packet creation unit 16 from the upper layer, and the transmission packet creation unit 16 is delivered. Since the packetized information has a size of 1 packet, it was confirmed whether the transmission credit number counting unit 14 was 1 or more. However, since it was 1 or more, 1 was subtracted and the transmission information was packetized in the transmission buffer 2. At the same time, the counter is set to 1 in the transmission packet count counter 15
Notified to add.

At this point, the packet transfer from the transmitting side P1 to the receiving side P2 is still continuing, and the transmission from the receiving side P2 to the transmitting side P1 is not performed. A little later than that, the count number of the update packet number counting unit 4 became the maximum number of received packets (300 in FIG. 6).
When the credit update determination unit 19 performs the determination process of FIG. 2 from the number of credits (= 300) that need to be updated, it is 255 × 1 + 45 = 300 and 1 <1 + 1 = 2 (2 transmission waiting information packets can be given. However, since there is only one transmission waiting information packet), it is judged that the credit cannot be updated by the piggyback credit, the processing is moved to the credit update packet creation unit 3, and the update packet number counting unit 5 is updated. Notified that the number has been cleared.

As described above, even when an attempt is made to update more credits than the number of transmission wait information packets, the credits can be updated by command packets as in the conventional case.

As described above, according to the first embodiment of the present invention, the number of transmission waiting information packets counted by the transmission waiting packet number counting unit 15 is referred to when a credit update request is made. It is determined whether or not the credit can be updated. If the credit can be updated, the piggyback credit embedding unit 19 is instructed to embed the credit. If the credit cannot be updated, the credit update packet creation unit 3 is instructed. Since the credit update determination unit 19 for issuing a packet creation instruction and the piggyback credit embedding unit 19 for embedding credit in a part of the transmission waiting information packet stored in the transmission waiting packet storage queue 18 are provided, Such an effect can be obtained.

Even when both transmissions are performed asynchronously, when a credit update request is made, it is checked whether there is an information packet waiting to be transmitted, and there is a transmission wait information packet and the credit is updated. If possible, credits are updated by embedding the credits in a part of the information packet, so that it is possible to reduce the credit update processing by the instruction packet as in the past and reduce the transfer load. And the transfer efficiency can be improved.

[Second Embodiment] Next, a second embodiment of the present invention will be described in detail with reference to the drawings.

(1) Description of Configuration FIG. 8 is a functional block diagram showing an example of the configuration of the packet transmitting / receiving apparatus of the second embodiment of the present invention. The packet transmission / reception device of the second embodiment of the present invention includes a transmission line control unit 1, a transmission buffer 2, a credit update packet creation unit 3, an update packet number counting unit 4, a counter subtraction unit 5, a reception line control unit 6, and reception. Buffer 7, response packet creation unit 8, received packet type determination unit 9, information packet processing unit 10, received packet storage queue 11, piggyback credit extraction unit 12, command packet processing unit 13, transmission credit number counting unit 14, transmission waiting Packet number counting unit 15,
The transmission packet creation unit 16, the piggyback credit embedding unit 17, the transmission waiting packet storage queue 18, the credit update determination unit 19, the timer processing count unit 20, and the timer processing reset unit 21 are provided. In the figure, 100 is a transmission packet, 110 is a reception packet, 120 is an upper layer transmission, and 130 is an upper layer reception.

That is, the packet transmitting / receiving apparatus of the second embodiment of the present invention is the same as the packet transmitting / receiving apparatus of the first embodiment of the present invention shown in FIG. 21 is added.

In FIG. 8, the same components as those shown in FIG. 1 are designated by the same reference numerals, and the description will be simplified or omitted.

(2) Description of Operation Next, the operation of the second embodiment of the present invention will be described in detail with reference to FIG.

The update credit number counting section 4 notifies the credit update determination section 19 when the update credit number reaches the maximum packet number. However, the credit update determination unit 19 refers to the count number of the transmission waiting packet number counting unit 15 and notifies the piggyback credit embedding unit 17 of the updated credit number when the credit can be updated by the piggyback credit. If piggyback is impossible, the timer processing counting unit 20 is notified.

When the timer is in the operating state, the timer processing counting section 20 keeps the timer as it is, and when the timer is in the reset state, the timer processing counting section 20 initializes and operates the timer. To do. Further, the transmission waiting packet number counting unit 15 notifies the credit update determination unit 19 of the count-up as well as the count-up.

Further, the credit update packet creating section 3 and the piggyback credit embedding section 17 notify the timer processing resetting section 21 that the credit has been updated, along with the processing up to this point. Timer processing reset unit 21
Resets the timer processing counting unit 20 and stops the operation of the counter.

As a result, if the number of transmission waiting information packets increases within the specified time of the timer, the credit update determination unit 19 determines whether or not the credit can be updated by piggyback at that time, and the credit can be updated. In this case, the process is advanced to the piggyback credit embedding unit 17 to update the credit by piggyback, and at the same time, the piggyback credit embedding unit 17 notifies the timer processing reset unit 21 to clear the timer and stop the timer. .

If the specified time has passed while the number of transmission waiting information packets is insufficient, the timer processing counting section 20 advances the processing to the credit update packet creating section 3 to update the credit by the command packet. To do.

By such a method, it is possible to further improve the probability that the credit can be granted by the method of embedding the credit in a part of the transmission waiting information packet.

As described above, according to the second embodiment of the present invention, when there is a credit update request, the number of transmission waiting information packets counted by the transmission waiting packet number counting unit 15 is referred to. It is determined whether or not the credit can be updated within the specified time counted by the timer of the timer processing / counting unit 20, and when the number of transmission waiting information packets increases and the credit can be updated within the specified time, the piggyback credit is given. When the credit embedding unit 17 is instructed to embed the credit and the credit update is impossible due to the shortage of the number of transmission waiting information packets within the specified time, the command update packet creation unit 3 creates the command packet via the timer processing counting unit 20. Credit update determination unit 19 for giving an instruction
And the piggyback credit embedding unit 19 for embedding credit in a part of the transmission waiting information packet stored in the transmission waiting packet storage queue 18, the following effects can be obtained.

As in the first embodiment, even when both transmissions are performed asynchronously, when a credit update request is made, it is checked whether there is an information packet waiting for transmission. If the transmission waiting information packet exists and the credit can be updated, the credit is updated by the method of embedding the credit in a part of the information packet, so that the conventional credit updating process by the instruction packet can be reduced. Therefore, the transfer load can be reduced and the transfer efficiency can be improved.

Further, as an effect peculiar to the second embodiment, by waiting for the increase or decrease of the number of transmission waiting information packets for a specified time, the probability that the credit can be embedded in the transmission waiting information packets can be increased.

[0093]

As described above, according to the present invention,
It is determined whether the credit can be updated by referring to the number of transmission waiting information packets. If the credit can be updated, the credit is controlled to be embedded in a part of the transmission waiting information packet. Such an effect can be obtained.

Further, even when both of the transmissions are performed asynchronously, when there is a credit update request, it is checked whether there is an information packet waiting to be transmitted, and there is a transmission waiting information packet. If the credit can be updated, the credit is updated by embedding the credit in a part of the information packet. Therefore, it is possible to reduce the conventional credit update processing by the instruction packet and reduce the transfer load. It is possible to improve the transfer efficiency.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a configuration example of a packet transmission / reception device that realizes a piggyback credit control method according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a process of a credit update determination unit of the packet transmission / reception device according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing a process of a piggyback credit embedding unit of the packet transmission / reception device according to the first embodiment of the present invention.

FIG. 4 is a time chart showing a credit update process by embedding in one information packet when asynchronous transfer is performed according to the first embodiment of the present invention.

FIG. 5 is a time chart showing a process when credit cannot be updated by embedding in one information packet when asynchronous transfer is performed according to the first embodiment of the present invention.

FIG. 6 is a time chart showing a credit update process by embedding in a plurality of information packets in the case where asynchronous transfers are performed according to the first embodiment of the present invention.

FIG. 7 is a time chart showing processing when credit cannot be updated by embedding in a plurality of information packets when asynchronous transfer is performed according to the first embodiment of the present invention.

FIG. 8 is a functional block diagram showing a configuration example of a packet transmission / reception device equipped with a timer function according to a second embodiment of the present invention.

FIG. 9 is a functional block diagram showing a configuration example of a packet transmission / reception device based on a credit process of a conventional example.

FIG. 10 is a time chart showing a credit update process by an instruction packet in the case of transmitting data at arbitrary timings in the conventional example.

FIG. 11 is a time chart showing a credit updating process by embedding in the case where it is arranged to transfer information packets of a response of the conventional example to each other.

[Explanation of symbols]

1 Transmission line control unit 2 Send buffer 3 Credit update packet creation unit 4 Update packet count section 5 Counter subtraction unit 6 Reception line control unit 7 Receive buffer 8 Response packet creation unit 9 Received packet type discrimination unit 10 Information packet processing unit 11 Received packet storage queue 12 Piggyback Credit Extraction Unit 13 Command packet processor 14 Transmission credit count section 15 Packet waiting count section 16 Transmit packet generator 17 Piggyback credit embedding department 18 Packet waiting queue for transmission 19 Credit update discriminator 20 Timer processing counting section 21 Timer processing reset section

Claims (6)

(57) [Claims] 1. A packet communication device that performs packet communication by transmitting a credit including the number of receivable information packets to a partner, whether or not the credit can be updated when there is a request for updating the credit. Determining means for determining whether or not the credit can be updated, embedding means for embedding the credit in a part of the transmission waiting information packet, and counting for counting the number of transmission waiting information packets Creating means and a command packet for updating said credit
Means and time measuring means for measuring time, wherein the determining means is the transmission waiting information counted by the counting means.
Specified time counted by the timekeeping means with reference to the number of report packets
It is determined whether the credit can be renewed within the
The number of information packets waiting to be transmitted increases within a fixed time
If it is possible to update the
Information packet waiting to be sent within the specified time after instructing to embed
If credit cannot be renewed due to insufficient number,
A packet communication device characterized by instructing a creating means to create a command packet . 2. The storage device further comprises storage means for storing a transmission waiting information packet, and the embedding means is stored in the storage means when the determination means determines that the credit can be updated. The packet communication device according to claim 1 , wherein the credit is embedded in a part of a transmission waiting information packet. 3. A packet communication device according to claim 1 or 2 is provided with any one of a host device such as a host computer and a peripheral device such as a printer, and the host device or the peripheral device has the same communication time. A communication line system existing on a line and updating the credit to the other party. 4. A credit updating method in a packet communication device that performs packet communication by transmitting a credit indicating the number of receivable information packets to a partner side, which can be updated when a credit updating request is made. a determination step of determining whether, and the buried burying credit to part of the transmission waiting information packet when it is determined that the possible credit update with該判based process, the counting of counting the transmission waiting number of information packets Process and creation process to create a command packet to update credits
And a time counting step of measuring time, and in the determining step, waiting for transmission counted in the counting step.
Regulations measured in the timekeeping process with reference to the number of information packets
Determine whether it is possible to renew the credit within the time, and specify
The number of information packets waiting to be sent increases within the time
If renewal is possible, credit is embedded in the embedding process.
And the number of information packets waiting to be sent
If the credit cannot be renewed in the current condition
A credit renewal method characterized in that an instruction packet creation instruction is given in order . 5. The method further comprises a storage step of storing a transmission-waiting information packet, wherein the embedding step stores the transmission stored in the storage step when the determination step determines that the credit can be updated. The credit renewal method according to claim 4 , wherein credit is embedded in a part of the waiting information packet. 6. The present invention is applicable when any of a host device such as a host computer or a peripheral device such as a printer existing on the same communication line updates credits to the other party. The credit renewal method described in 4 or 5 .