JP3477851B2 - Communication control device and switching system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication control method, a communication control device, and a switching system, and more particularly, to a highly multiplexed communication control device and a frame reception control function in the switching system.

[0002]

2. Description of the Related Art For example, as reported in 1993 Spring Meeting of the Institute of Electronics, Information and Communication Engineers B-469 "Timer Processing Method in Highly Multiplexed Communication Control LSI", HDLC
In recent years, communication control devices that perform frame communication in accordance with communication protocols such as the above have been highly multiplexed so that the number of connections that can be processed reaches several thousand. As one of the technical problems in such a highly multiplexed communication control device,
There is scheduling to be processed.

In order to process the reception frames of a plurality of connections, the high-division communication control device conventionally issues a process activation event corresponding to the reception frames stored in the reception buffer, and this is a queue (hereinafter referred to as an event queue). Are sequentially registered, the processing device extracts events from the head of the event queue in sequence, and the received frame corresponding to the event is read from the reception buffer and processed.

[0004]

In the highly-multiplexed communication control device that processes a received frame by using the above-mentioned event queue, the event issued upon receiving the frame is unconditionally registered in the event queue. Therefore, when a large number of frames are intensively transmitted from a specific user or terminal device within a certain period, the memory capacity of the event queue is unduly consumed by the plurality of events of the specific user, and There is a risk that other users' events will be discarded if the memory capacity is insufficient. In this case, system resources such as the function of the processor connected to the communication control device are occupied by the received frame processing from the specific user, and the service to other users is restricted.

For example, a signal processing device of an exchange, which is a kind of communication control device, receives a signal frame for call control from a calling terminal device through a signal connection before setting a data connection between the terminal devices. . When a particular terminal device frequently issues control signals for call setup / cancellation due to, for example, device failure or user operation error,
A large number of signal frames from the specific terminal reach the signal processing device in a concentrated manner, and the call control processing device of the exchange repeats setting / releasing of the specific connection without meaning.
There is a problem that the processing regarding the connection of other users is delayed.

An object of the present invention is to provide a communication control method for performing a reception processing operation while selectively discarding some of reception frames having a connection identifier, and a communication device to which the communication control method is applied.

Another object of the present invention is to provide a communication control method capable of appropriately distributing the resources of the communication control device and the processing device connected to the communication control device among the connections handled by the communication control device.

Still another object of the present invention is to provide a communication control device having a function of limiting reception processing for frames transmitted intensively from a specific user or terminal device.

Still another object of the present invention is to provide a function of rejecting the frame processing of a control signal frame transmitted in the form of a packet or a cell from a terminal device and received under a specific condition. To provide an exchange system.

[0010]

In order to achieve the above object, the communication control method of the present invention manages the number of received frames waiting for protocol processing in the communication control device in association with the connection identifier. When a new frame is received from the transmission line, it is determined whether or not the number of protocol processing waiting reception frames corresponding to the connection identifier of the reception frame has reached a predetermined threshold, and the threshold has been reached. In this case, the new received frame is discarded.

The threshold value as the standard for discarding received frames and the number of received frames waiting for protocol processing are managed in group units after grouping a plurality of connection identifiers in advance, and when a new frame is received, A new received frame may be discarded when the number of protocol processing waiting received frames corresponding to the group to which the connection identifier of the received frame belongs has reached a preset threshold value.

In the grouping described above, for example, a plurality of connections set by a plurality of terminal devices belonging to the same user (subscriber) are grouped into one group, so that frame reception restriction is applied to each user. You can do it.

According to the above communication control method, each frame is transmitted in the form of being divided into a plurality of packets or cells (fixed length packets), and the communication control device assembles a reception frame from the plurality of packets received from the transmission path. It can also be applied in cases.

In the embodiment of the present invention, after the communication control device stores a new received frame in the received frame buffer memory, the above-mentioned judgment for frame discard is performed, and the number of received frames waiting for protocol processing reaches a threshold value. If not, register a reception event including information for identifying the new reception frame in the event queue,
After performing a predetermined protocol process on the reception frames corresponding to the reception events sequentially extracted from the event queue, the reception frame is notified to the data processing device connected to the communication control device.

The communication control device according to the present invention, when a new frame is received from the transmission line and a memory means for storing the number of received frames in the protocol processing wait state in association with the connection identifier, By referring to the memory means, it is determined whether or not the number of received frames waiting for protocol processing corresponding to the connection identifier of the received frame has reached a threshold value. If the threshold value has been reached, the received frame is discarded, otherwise. In some cases, it has a first means for putting the received frame in a protocol processing waiting state and a second means for executing a predetermined protocol processing for the received frame in the protocol processing waiting state.

According to a preferred embodiment, the memory means stores a threshold value indicating the allowable value of the frame waiting for protocol processing in association with each connection identifier, and the first means receives a new frame from the transmission path. At this time, it is determined whether the received frame should be discarded by reading from the memory means the number of received frames waiting for protocol processing corresponding to the connection identifier of the received frame and the threshold value.

Further, the exchange system according to the present invention comprises a plurality of input ports and output ports, and selects a packet received from each input port as one of the output ports determined according to the header information of each packet. Switch for outputting a signal, a signal processing device connected to the switch for performing a predetermined protocol process, and a control device connected to the signal processing device, wherein the signal processing device is a protocol processing device. Memory means for storing the number of received frames in a waiting state in association with the connection identifier, and when a new control signal frame is received from the switch, refer to the memory means to connect the received frames. If the number of received frames waiting for protocol processing corresponding to the identifier has reached the threshold value, If was discarded the received frame,
Otherwise, it has a first means for putting the received frame in a protocol processing waiting state and a second means for executing a predetermined protocol processing for the received frame in the protocol processing waiting state. The first and second
The means can be constituted by separate processors.

[0018]

According to the present invention, the number of received frames waiting for protocol processing in the communication control device is managed in correspondence with a connection or a connection group, and the number of frames waiting for protocol processing is a predetermined threshold value. Since the new received frame of the connection that has reached the point is discarded without performing the protocol processing, the resource or service function of the communication control device and the processing device connected to this is prevented from being occupied by a specific user. It can be avoided.

[0019]

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

FIG. 1 shows a signal processing unit (1 according to the present invention.
00) including the subscriber line switching system.

10A to 10M are lines 20-i, respectively.
This is a user terminal connected to a subscriber line switchboard (1000) via a. In this example, two terminals 10A and 10B belonging to the user 1 share the line 20-1, and the terminal 10A has two signal connections for communicating with the signal processing unit 100 of the subscriber line exchange. C-0 and C-1 are set, and the terminal 10B sets one signal connection C-2 with the signal processing unit 100. Further, the terminal 10C belonging to the user 2 sets two signal connections C-3 and C-4 for communicating with the signal processing unit 100 on the line 20-2.

The above-mentioned signal connection C-i (i =
0 to 4) are different from the data connection D-i used for communication between the terminals, and each terminal 10 executes a predetermined call setup procedure with the exchange through the signal connection C-i. , Communicate with the other terminal via the data connection D-i.

The subscriber line exchange 500 accommodates a plurality of lines 20-i connected to the terminals 10 of the respective users, and has a signal connection C-i and a data connection D-.
a switch 200 for exchanging i, a signal processing unit (100) for controlling transmission / reception of control signals to / from each terminal,
The control unit 300 is connected to the signal processing unit 100 and executes a control operation such as setting and releasing a call (data connection) between terminals. The exchange 500 is provided with a line interface (interface) for performing a header conversion operation of an input / output packet (or cell) for each line 20-i. Is omitted.

The signal processing unit 100 has a LAPD (Link Acc
ess Procedure on the D-channel), SSCOP (Serv
It executes communication control protocols such as ice-specific connection-oriented protocol).

FIG. 2 is a block diagram showing the functions of the signal processing unit 100.

Reference numeral 111 is a reception line control unit connected to the reception line 230R from the switch 200, and the control signal (reception data) transmitted from the terminal device via the signal connection is used for frame separation, synchronization, etc. After performing the processing of (1), the received data is passed to the frame receiving section 112. The frame reception unit 112 analyzes the received data, generates an event indicating frame reception, and passes the event to the event reception control unit 113. Upon receiving the event, the event reception control unit 113 refers to an event management information table described later to check whether the event can be registered in the event queue in the queue 140. Register the event at the end of the event queue.

Reference numeral 150 denotes a protocol processing unit that sequentially takes out events from the head of the event queue, executes communication protocol processing for each event, and then notifies the control unit 300 of the received data. When the protocol processing unit 150 needs to transmit a response frame to the terminal, it creates a transmission frame and passes it to the frame transmission control unit 161. When the control information is transmitted from the control unit 300 to each terminal, the transmission command is queue 1
The transmission frame is registered in the command queue in 40 and the transmission frame is passed to the frame control unit 161.

The frame transmission control unit 161 transmits the transmission frame received from the protocol processing unit to the transmission line control unit 1
Hand it over to 62. The transmission line control unit 162 sends the received transmission frame to the switch 200 via the transmission line 230T.

When the control signal is transmitted / received to / from the terminal device in a packet (or fixed length cell) format, the receiving line control unit 111 converts the received packet into a frame (assembling). Then, the transmission line control unit 162 performs conversion processing (segmentation) of the transmission frame into a packet.

FIG. 3 shows the structure of the event management information table 170 referenced by the event reception control unit 113.

The event management information table 170 has a connection number 170 corresponding to a subscriber (user) 170a.
b, which is for managing the number of events, and as the information indicating the number of events, a count value 170c indicating the number of events currently staying in the event queue for each user.
And a permissible value (upper limit value) 170d of the stay event preset for each user are stored.

The event reception control unit 113 refers to the event management information table 170 for each event received from the frame reception unit 112 and checks whether or not it can be registered in the event queue 140. That is, the event reception control unit 113 accesses the table 170 using the connection number of the received event as a key, and compares the stay event counter value 170c for each user to which the connection belongs with the upper limit 170d. If the count value has not reached the upper limit value, the reception event is registered in the event queue and the count value is incremented. If the count value reaches the upper limit and enters, it is determined that there are too many reception events from the corresponding user, and the reception events are discarded.

As described above, the event reception control unit 113 controls the registration of the reception event in the event queue 140 for each user, so that the specific user occupies the reception processing capability of the signal processing unit (100). Can be prevented. In addition, the event reception control method described above
In addition to the signal processing unit in the exchange, general CCP (Comm
It is also applicable to unication Control Processer).

As another embodiment of the present invention, FIG. 4 shows an AT including a signal processing unit 300 to which event acceptance control is applied.
The whole block diagram of M (Asynchronous Transfer Mode) exchange 500 'is shown. The ATM switch 500 ′ is a communication line (VC: Virtual Ch
annel) to realize multimedia communication such as voice, data, and video between terminals.

The ATM switch 500 'has a switch unit 20.
0, the signal processing unit 100, the control unit 300, and subscriber line corresponding units (interfaces) 210A to 21 provided for each ATM subscriber line 240 (240A to 240L).
0L and a trunk line 241 for connecting to another exchange
Each of (241M to 241Q) includes a trunk line corresponding portion (interface) 210M to 210Q.

The ATM subscriber line 240, the trunk line 241, and the switch input / output port 220 (220A to 220A)
20Q) and internal line 230 (230R, 230
On the T), communication is performed in units of 53-byte fixed-length packets called ATM cells.

Each interface 210 terminates the physical layer of the ATM line (subscriber line or trunk line) by performing cell synchronization or the like, and receives A from these external lines.
VPI / VCI included in the header of the TM cell
(Virtual Path Identifier / Virtual Channel Identifi
er) conversion, and then ATM switch input port 2
20 and the VPI / V included in the header part of the ATM cell received from the output port of the ATM switch.
After the CI value is converted, it has a function of sending it to an external ATM line. In addition, VPI / VC on ATM line
I value and internal VPI / VC that is valid inside the ATM switch
The correspondence with the I value is given from the control unit 300 to each interface as call connection information at the time of call setup.

The switch unit 200 uses the ATM cell input from the input port as VPI / included in its header section.
Allocate to the output port corresponding to the VCI value. The control ATM cell including the call control information is distributed to the internal line 230R, which is one of the input / output ports, and the signal processing unit 10
Input to 0. In addition, the control ATM cell output from the signal processing unit 100 is input to the switch unit 200 via the internal line 230T and is included in the VPI / VPI included in the header unit.
It is output to any of the other output ports 220 corresponding to the VCI value.

FIG. 5 shows a frame F (F1, F2, ...) Handled by each terminal 10 or control unit 300 and an ATM cell 70.
The relationship with (70-1, 70-2, ...) Is shown.

Each frame F comprises an information section 61 and a trailer section 62. Each frame F is divided into a plurality of data blocks each having a fixed length of 48 bytes, and each data block (information section) 72 is added with a 5-byte ATM header 71 indicating the destination information.
It becomes 0. As the destination information, 20- or 24-bit VPI / VCI is set. The information section 72 in the ATM cell is called "payload".

In this example, the information part 61 of the frame F is S
SCOP-PDU (protocol data unit), trailer unit 62 is CPCS-5 (Common Part Convergence Sublay).
er type 5) error detection code, the contents of the protocol processing to be executed by the communication processing apparatus are shown in protocol stacks 1002 to 1005. Details of these protocol stacks will be described later.

FIG. 6 shows the signal processing unit 100 and the control unit 3.
00 and signal processing protocol stacks 1001 to 10
The relation with 07 is shown.

Physical layer 1 of the protocol stack
001 defines the waveform of the transmission signal on the ATM line,
The ATM layer 1002 has a function of converting the data frame F into ATM cells and a function of assembling the received ATM cells into a frame F. Also, CPCS-5
(Common Part Convergence Sublayer type 5) 100
3 adds a 4-byte bit error detection code as a trailer to the frame to be transmitted and detects a transmission error using the bit error detection code included in the received frame. In this embodiment, the above CPCS-5; 1003
Among the functions of the ATM layer 1002 and the ATM layer 1002, the function related to reception is executed by the cell reception unit 130R, and the function related to transmission is executed by the cell transmission unit 130T.

The SSCOP 1004 has functions such as retransmission of error frames and flow control of transmitted / received data. In addition, UNI-SSCF (User Network Interface-Ser
viceSpecific Coordination Function) 1005 is S
The service provided by the SCOP 1004 is Q. 93B; has a function of converting to a service requested by 1006. In this embodiment, the UNI-SSC is used.
The communication control protocol unit 150 executes the functions of F; 1005 and SSCOP; 1004.

Q. 93B; 1006 is ITU-T (In
ternational Telecommunication Union-Telecommunica
standardization sector)
It is a protocol standardized as layer 3 of DN (Integrated Services Digital Network). Further, the call control (call processing) 1007 is performed by the above Q. 93B; an upper layer of 1006, which has a function of controlling the switch unit 200 based on signal information, for example. In the present embodiment, the above-mentioned Q. The control unit 300 realizes the function of 93B; 1006 and the function of the call processing 1007.

In FIG. 6, the cell receiving unit 130R is
When the cell is received from the TM internal line 230, the information part of the cell having the same VPI / VCI is assembled into the reception frame F based on the header part of each cell. Cell receiver 130R
Is the CPC for the received frame F that has been assembled.
S-5: After executing the protocol processing of 1003, the reception frame F is stored in the reception frame buffer 310R, and the reception event is issued to receive the reception event queue 1
Register at 40R. At this time, the event reception control described above is performed.

The communication control protocol unit 150 sequentially takes out the reception events registered in the reception event queue 140R, and outputs SSCOP; 1004 and UNI-SSCF;
The procedure of 1005 is executed, and the status indicating the execution result is registered in the status queue 160R. Control unit 300
On the basis of the status read from the status queue 160R. 93B; 1006 and call processing 1007
To execute.

On the other hand, the transmission operation of the frame generated by the control unit 300 is performed as follows.

The control unit 300 prepares the frame to be transmitted in the transmission frame buffer 310T and then registers the transmission command in the command queue 160T. The communication control protocol unit 150 sequentially takes out the transmission command from the command queue 160T, executes the protocol procedure of SSCOP; 1004 and UNI-SSCF; 1005 for the transmission frame in correspondence with each transmission command, and then transmits the transmission event. The transmission event is registered in the queue 140T. The cell transmission unit 130T sequentially takes out the transmission events from the transmission event queue 140T, reads out the transmission frame corresponding to each transmission event from the transmission frame buffer 310T, and C
The protocol processing of PCS-5; 1003 is executed. After that, the transmission frame is divided into a plurality of blocks, and the AT
It is sent to the ATM internal line 230T as an M cell.

Here, a problem in the reception processing when a large number of reception events occur will be described with reference to FIG.

Many transmission frames may arrive at the signal processing unit 100 from the same user in a short time due to device failure or other reasons. For example, if the value of the polling timer, which is one of the initialization parameters of the terminal, is set to an abnormally small value, the terminal frequently issues polling frames,
These are transmitted to the signal processing unit.

FIG. 7 shows that the terminal 10Y of the user Y is received within the time T required for the reception processing of one frame in the signal processing unit 100.
-1, 10Y-2 to frames 60-7 to 60-10
Are transmitted intensively, and immediately thereafter, the terminal 10 of the user X is
The case where the frame 60-11 is transmitted from X is shown. On an actual ATM line, the above-mentioned frames 60-i
Are divided into a plurality of ATM cells and transmitted, but here, for simplicity, they are shown in frame units.

In this case, in the signal processing unit 100, while the communication control protocol unit 150 is executing the receiving procedure of the frame 60-7, the cell receiving unit 130R causes the subsequent frames 60-8, 60-9, The reception events 30-8, 30-9, and 30-10 for 60-10 are issued one after another. Assuming that the capacity (queue length) of the reception event queue 140R is “3” (actually, it is longer), the queue is full when the reception event 30-10 is registered in the reception event queue 140R. Therefore, the frame 6 from the user X received thereafter is
As for 0-11, the reception event cannot be registered in the queue 140R and must be discarded.

That is, the receiving capability of the signal processing unit 100 is occupied by the intensive frame transmission performed by the user Y, which has a bad effect on other users. In this case, if an upper limit value is set in advance for the number of events that can be accumulated in the reception event queue for each user, for example,
If the event upper limit value for the user Y is set to "2", the reception event 30-10 of the frame 60-10 is discarded, and instead of this, the frame 6 from the user X is replaced.
The reception event 30-11 of 0-11 can be accepted.

FIG. 8 is a block diagram showing details of the functions of the reception processing system of the cell reception unit 130R and the communication control protocol unit 150.

The cell receiving unit 130R uses the ATM internal line 2
A cell assembling unit 131 that obtains a connection number from the VPI / VCI value of the reception cell input from 30R and assembles a frame from the information section of the reception cell for each connection.
And the assembled frame is received from the cell assembly unit 131, and the CPC such as the bit error detection code is received from the frame.
Cut out the S-5 trailer (62 in Fig. 5) and CPCS-
5; 1003 is executed, the remaining frame is stored in the reception frame buffer 310R as the reception frame F, and the reception event 30 composed of the connection number 31, the frame length 32 and the buffer address 33 is created by 742. Receive event enqueue section 1
The reception CPCS processing unit 132 to be delivered to 33 is provided.

The reception event enqueue section 133 refers to the reception event management information table 170 and controls the number of reception events received for each subscriber. The reception event management information table 170 is the reception group information table 171.
And a stay event information table 172.
The reception group information table 171 shows the correspondence relationship between the connection number 171b and the reception group name (user name) 171a to which the connection belongs, which makes it possible to know which user each frame (connection) belongs to. it can. The contents of the reception group information table 171 are as follows.
Given by.

The staying event information table 172 is made up of records corresponding to each receiving group, and for each receiving group (user) 172a, a staying number counter 172b showing the number of receiving events currently staying in the receiving event queue 140, Upper limit 172 that represents the number of events that can be retained
Remember c and. In the stay event information table 172, the record having the group name “whole” is
The total number of staying events and the upper limit value (queue length of received events) are stored for all connections connected to the signal processing unit 100.

The staying number upper limit value 172c is set by the control unit 300 when setting each connection. Control unit 3
00 sets the staying number upper limit value 172c to a large value for subscribers who use a large amount of traffic and sets the staying number upper limit value to be small for subscribers who use a large amount of traffic according to the used traffic declared by each subscriber at the time of line contract. . Residence number counter 172b
Is counted up by the reception event enqueue unit 133 when an event is registered in the reception event queue 140R, and is counted down by the communication control protocol unit 150 when dequeueing from the reception event queue 140R.

The reception event enqueue section 133 determines whether or not the reception event queue 140R is full based on the retention number (R-0) of all groups in the retention event information table 172. If it is not in the full state, the reception group information table 171 is referred to obtain the reception group name 171b corresponding to the connection number 171a of the reception event 30 that is the target of enqueuing, and then the reception event information table 172 is used to retrieve the reception group. A record having the same group name 172a as the name is searched, and the staying number counter 172b and the staying number counter 172c are compared. If the counter value 172b has reached the upper limit value 172, the reception event 30 is discarded. If the counter value does not reach the staying number upper limit value, the reception event 30 is enqueued in the reception event queue 140R, and the value of the staying number counter 172b corresponding to this is incremented by one.

The communication control protocol unit 150 comprises a reception event dequeue unit 151 for sequentially reading the reception events 30 from the reception event queue 140R, and a reception protocol execution unit 152 for executing protocol processing on the dequeued reception events 30. There is. When the reception event dequeuing unit 151 extracts the reception event 30 from the reception event queue 140R, the reception event dequeue unit 151 refers to the reception group information table 171 to obtain the reception group name 171a corresponding to the connection number 31 of the reception event 30, and accumulates the retained event information. On the table 172, the staying number counter corresponding to the reception group name is decremented by 1.

In this embodiment, connections belonging to the same user are set as one group for each user, and the number of reception events received is controlled for each group. However, the connection group that is the unit for reception event reception control is For example, a unit other than the user may be adopted, such as a terminal unit.

FIG. 9 shows a specific device configuration of a circuit section including the signal processing section 100 and the control section 300 having the above-described reception event acceptance control function.

The signal processing unit 100 has an ADP (Adaptation) processor 130 for realizing the function of the cell receiving unit 130R and the function of the cell transmitting unit 130T shown in FIG. 6, and a protocol for realizing the function of the communication control protocol unit 150. And a processor 150 '. These two processors, via the internal bus 191, control memory 17 which constitutes the reception event control information table 170 shown in FIG.
0 ', and is connected via the internal bus 192 to the buffer memory 310 that constitutes the reception frame buffer 310R and the transmission frame buffer 310T shown in FIG.

The internal bus 192 has a processor 300 'constituting the control section 300 and a memory 320 for storing a control program to be executed by the processor.
And the bus arbiter 330 are connected, and the processor 300 and the processor 1 are connected by the bus arbiter 330.
Buffer memory 3 by 30 and processor 150 '
10 access is controlled. Receive event queue 13
The 0R, the transmission event queue 130T, the status queue 160R, and the command queue 160T are configured by using a part of the control memory 170 ′ or the buffer memory 310.

[0066]

As described above, according to the present invention,
Since the signal processing device (communication control device) has a function to limit the registration of received events to the event queue for connections that have reached a predetermined condition before the event queue becomes full, It is possible to prevent monopolization due to an abnormal transmission operation from a terminal of a specific user, and to avoid adverse effects on communication of other users.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a subscriber line exchange system that is an example of an application system of the present invention.

2 is a block diagram showing functions of a signal processing unit 100 of a subscriber line exchange 500 in FIG.

FIG. 3 is a diagram showing an example of an event management information table used for event reception control in the signal processing unit 100.

FIG. 4 is a diagram showing a configuration of an ATM exchange to which the present invention is applied.

FIG. 5 is a diagram showing a relationship between a transmission frame and an ATM cell.

6 is a diagram for explaining the function of the signal processing unit 100 in FIG.

FIG. 7 is a diagram for explaining the necessity of reception event reception control in the signal processing unit 100.

FIG. 8 is a diagram for explaining a reception event acceptance control function in the signal processing unit 100.

9 is a block diagram showing a specific circuit configuration of a signal processing unit 100 and a control unit 300 having the functions shown in FIG.

[Explanation of symbols]

10 ... User terminal, 100 ... Signal processing unit, 111 ...
Reception line control unit, 112 ... Transmission line control unit, 113 ...
Event reception control unit, 130R ... Cell receiver, 130
T ... cell transmitter, 140 ... event queue, 150 ...
-Protocol processing unit, 161, ... Frame transmission control unit, 1
62 ... Transmission circuit control unit, 200 ... Switch, 210 ...
-Interface, 300 ... Control unit, 500 ... Subscriber line exchange.

Front page continued (72) Inventor Shinichi Iwaki 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Hitachi, Ltd. Information & Communication Division (72) Inventor Satoshi Shimizu 216 Totsuka-cho, Totsuka-ku, Yokohama, Kanagawa Hitachi Mfg. Co., Ltd. (56) Reference JP-A-3-247145 (JP, A) JP-A-63-42543 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 29/04 H04L 12/28 H04L 29/06

Claims (11)

(57) [Claims] 1.Connected between the transmission line and the processing unit,
For a transmission / reception frame having a function identifier
A control method for a communication control device that executes protocol processing.
I mean A receiver waiting for protocol processing in the communication control device
Manages the number of incoming frames in correspondence with the connection identifier
Well, When a new frame is received from the above transmission line, the reception
Protocol processing corresponding to the connection identifier of the frame
Whether the number of received frames waiting for reception reaches a predetermined threshold
If the threshold is reached, the new
Discard the frame The connection identifiers are divided into groups and each group
A threshold is stored for each and a new frame is added from the transmission line.
When a frame is received, the connection identification of the received frame
Waiting for protocol processing corresponding to the group to which the child belongs
If the number of received frames reaches the threshold, the new reception
A communication control method characterized by discarding a communication frame . 2. The new frame is received from the transmission line in the form of being divided into a plurality of packets, the packet received from the transmission line is assembled into a reception frame, and then the judgment for discarding the frame is performed. Claims characterized in that
1. The communication control method according to 1. 3. The new reception frame is stored in a reception frame buffer memory and then a judgment for discarding the frame is made. When the number of reception frames waiting for protocol processing does not reach a threshold value, the new reception frame is received. A reception event including information for specifying a frame is registered in the event queue, and a predetermined protocol process is performed on the reception frame corresponding to the reception event sequentially extracted from the event queue, claim and notifies the processing unit 1 or
The communication control method according to claim 2 . 4.Communication connected between transmission line and processing unit
A control device, The number of received frames waiting for protocol processing is
Memory hand to store in association with the Nation identifier
Dan, When a new frame is received from the transmission line, the message
Memory connection means to identify the connection of the received frame
Number of received frames waiting for protocol processing corresponding to child
If it has reached the threshold value by judging whether the value has been reached
Discards the received frame, otherwise the received frame
First means for putting a ram into a waiting state for protocol processing
When, For received frames in the above protocol processing wait state
Second means for executing a predetermined protocol process according to
Equipped with The memory means groups the connection identifiers
Number of frames waiting for protocol processing for each group
Memorize the threshold of The first means receives a new frame from the transmission path.
, The received frame is connected from the memory means.
Group to which the application identifier belongs and the corresponding protocol processing
Read the number of frames waiting for reception and the threshold, and
It is characterized by making a judgment as to whether or not it should be discarded in the frame
Communication control device . 5. A communication control device connected between a transmission line and a data processing device, wherein a plurality of packets are received from the transmission line and assembled into a reception frame, and a transmission frame is divided into a plurality of packets. And a second processor for executing protocol processing on the reception frame assembled by the first processor means and the transmission frame received from the data processing device.
And a memory for storing the number of received frames waiting for protocol processing by the second processor means in association with a connection identifier, and the first processor stores a new received frame Each time it is assembled, it is determined whether the number of received frames waiting for protocol processing corresponding to the connection identifier of the received frame has reached the threshold value by referring to the memory, and if the threshold value has been reached, the received frame is discarded. If not, the communication control device is provided with means for putting the received frame into a waiting state for protocol processing by the second processor. 6. The communication control device according to claim 5 , further comprising a buffer memory for storing a reception frame and an event queue memory for accumulating a predetermined number of events, wherein the first processor is If the number of received frames waiting for protocol processing corresponding to the connection identifier of the received frame has not reached the threshold value, the new received frame is written in the event queue memory. A reception event including information for specifying is registered, and the second processor performs a predetermined protocol process on a reception frame in the buffer memory corresponding to the reception event read from the event queue memory. Communication control device. 7. The memory stores a threshold value indicating an allowable value of a frame waiting for protocol processing in association with each connection identifier, and the first processor stores the threshold value from the memory each time the new frame is assembled. 6. The method according to claim 5 , wherein the number of received frames waiting for protocol processing corresponding to the connection identifier of the received frame and the threshold value are read to determine whether or not the received frame should be discarded.
6. The communication control device according to item 6 . 8. The memory divides the connection identifier into groups and stores a threshold value indicating an allowable value of a frame waiting for protocol processing for each group, and the first processor assembles the new frame each time. , claim, characterized in that from the memory read and the received frame of the connection identifier is a protocol processing signal waiting number of received frames corresponding to the group and the threshold belonging, it is determined whether to discard to the frame 5
Alternatively, the communication control device according to claim 6 . 9. The first processor has means for selectively counting up the number of frames waiting for protocol processing in the memory based on a connection identifier of the received frame, and the second processor has 6. The apparatus according to claim 5, further comprising means for selectively counting down the number of frames waiting for protocol processing in the memory based on the connection identifier of the received frame subjected to protocol processing.
The communication control device according to claim 8 . 10.Has multiple input and output ports
The packet received from each input port
One of the above output ports determined according to the header information
To the switch for selectively outputting to
Signal processing to perform the connected predetermined protocol processing
From the device and the control device connected to the signal processing device
And the above signal processing device The number of received frames waiting for protocol processing is
Memory hand to store in association with the Nation identifier
Dan, A new control signal frame is received from the above switch
At this time, referring to the memory means, the connection of the received frame
Protocol processing corresponding to the transmission identifier
To determine if the number of games has reached the threshold,
If so, the received frame is discarded, otherwise
To put the received frame in the waiting state for protocol processing
The first means of For received frames in the above protocol processing wait state
Second means for executing a predetermined protocol process according to
Have The memory means groups the connection identifiers
Number of frames waiting for protocol processing for each group
Memorize the threshold of The first means provides a new control signal frame from the transmission line.
Frame is received, the received frame is received from the memory means.
Corresponding to the group to which the connection identifier of
Reads the number of received frames waiting for tocol processing and the threshold,
To determine whether to discard the received frame
A characteristic exchange system. 11. A communication control device for executing a communication protocol on a reception frame of a plurality of multiplexed connections, wherein the plurality of connections are divided into groups, and a count value representing the amount of resources in use is allowed for each group. The threshold value indicating the resource amount is stored, and when a new frame is received, the count value of the used resource amount corresponding to the connection of the received frame and the threshold value are referred to, and the count value reaches the threshold value. If not, resource allocation is rejected, and if not, resource is allocated and protocol processing for the received frame is executed.