JPH11243414A - System and method for congestion control in packet exchange network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the overall network from being in a congested state and at the same time to have services for a subscriber improved, when part of a packet exchange enters in congested state. SOLUTION: When too many packets concentrate upon a packet exchange X5, it is in overloaded state and the packet exchange X5 detects that a CC use rate or a memory use rate is in congestion state by exceeding a preset threshold, the packet exchange X5 notifies of it to a maintenance person at a network maintenance center 10 by issuing an autonomous message. When the maintenance person knows by the autonomous message that the packet exchange X5 is congested, he notifies other packet exchanges A2, B3 and N4 in the network that the exchange S5 is being congested. The packet exchanges A2, B3 and N4 that receive command notification perform a call set processing, when it is within the number of self calling reception calling, but otherwise performs call cut processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a congestion control system and a congestion control system in a packet-switched network, and more particularly to a case where the amount of packets in the network rapidly increases in a short time and a certain packet switch becomes congested. The present invention relates to a congestion control method and a congestion control method in a packet switching network for preventing the entire network from becoming congested due to the congestion state of the exchange.

[0002]

2. Description of the Related Art As a first conventional example of this kind of conventional technology, in the technology disclosed in Japanese Patent Application Laid-Open No. 7-46272, a congestion state due to an overload of a packet switch is used for selective connection. When detected as congestion due to call setting, or when detected as congestion due to a setting request for fixed connection, a signal for newly requesting call setting for selective connection or a signal for requesting setting for fixed connection , The exchange rejects the setting, and the exchange does not regulate data packets already in communication or signals requesting call release. A congestion control method in a packet network is disclosed.

[0003] Next, the second of the prior art of this kind is described.
Will be described with reference to the drawings.

FIG. 6 is a block diagram showing a second conventional packet switching network.

In FIG. 6, this second conventional example shows the contents disclosed in Japanese Patent Laying-Open No. 7-177175, and relates to the possibility of temporarily changing the congestion restriction class based on a contract with the subscriber a in advance. The information is registered in the subscriber file of the station A, and the station temporarily changes the congestion regulation class of the subscriber to the priority class when a predetermined call involves a request for temporarily changing the congestion regulation class. And perform the processing. When the call is restored, the temporarily changed priority class is restored to the original congestion restriction class. Alternatively, the station side performs packet communication during the non-congestion regulation of the subscriber according to the subscriber's congestion regulation class, and performs packet communication during the congestion regulation according to the priority class when there is registration by referring to the registration.

[0006]

In this prior art,
In a packet-switched network, if the amount of packets in the network rapidly increases within a short time, the packet switch may be overloaded and the packet switch may become congested.

[0007] For example, in the case of congestion, refer to
As shown in US Pat. No. 6,272, a CR packet requesting a new call setup is rejected, and a data packet already in communication or a CI packet requesting a call disconnection is rejected.
Switches usually do not regulate. In this case, there is a problem that all CR packets for a new call setting request that becomes congested are rejected, and a new call setting cannot be performed.

Further, as disclosed in Japanese Patent Application Laid-Open No. 7-177175, in order to set up a new call at the time of congestion,
A priority class is fixedly or temporarily assigned to each subscriber, and call setting can be performed according to the priority class.
In this case, if only a high-priority subscriber performs a CR packet for a call setup request using a large number of logical channels, the amount of packets in the network does not decrease so much that the congestion state is hard to recover. There is a point. .
This will be described below with reference to the drawings.

FIG. 7 is a block diagram showing an example of a third conventional packet switching network, and FIG. 8 is a diagram showing an operation sequence of the third conventional example.

In FIG. 7, packet switches A, B,
N and X are a part of a packet switch constituting a packet switching network, and subscribers A, B, N and X are accommodated in the packet switches A, B, N and X, respectively.
The subscriber X is a host computer, the subscribers A, B, and N are terminals. The subscribers A, B, and N are subscribers of a priority class capable of setting up a call even during congestion, and use many logical channels. Call to the subscriber X to perform communication.

In FIG. 8, when the subscribers A, B, and N transmit CR packets on a large number of logical channels when the subscriber X is out of order or closed, the CR packets concentrate on the exchange X. The subscriber X cannot set up the call because it is in trouble or is closed, and the subscriber A, B, and N cannot set up the call because of the CI packet from the exchange X. The call cannot be set up and the call is disconnected by the CI packet. In this way, the call setting and the call disconnection are repeated, and the packet switch X becomes overloaded and becomes congested.

Even during the congestion period, the subscribers A, B, and N are trying to set up a call using a number of logical channels because they are subscribers of a priority class capable of setting up a call. In this way,
Since the call setup and the call disconnection are repeated, the congestion of the packet switch X is not restored, and congestion may reach other packet switches, which may cause the entire network to become congested. is there.

As described above, the third conventional example has the following problems.

The first problem is that it is difficult to recover the congestion after the packet switch X shown in FIG. 7 becomes congested in an overloaded state because the subscriber X is in trouble or is closed.

The reason is that when the subscribers A, B, and N cannot set up the call and the call is disconnected, the subscribers try to set up the call again.
This is because packets continue to concentrate on

The second problem is that if the packet switch X shown in FIG. 7 becomes overloaded and becomes congested while the subscriber X is out of service during a failure, the subscriber cannot set up a call. .

The reason is that in a congested state, the exchange regulates all call settings from the subscriber in order to recover the congested state.

(Object of the Invention) An object of the present invention is to limit the acceptance of calls from subscribers in accordance with the number of accepted calls set for each subscriber line when the packet switching network is congested. By controlling network congestion, and in a congested state, it is possible to set up calls for calls within the number of call acceptance calls preset for each subscriber line, thereby providing services to subscribers more than before. Another object of the present invention is to provide a congestion control method and a congestion control method in a packet switching network, which can improve the performance.

[0019]

SUMMARY OF THE INVENTION A congestion control system in a packet switched network according to the present invention accommodates a plurality of subscriber terminals or subscriber units via a plurality of subscriber lines and is connected via a network. In a packet switching network having a plurality of packet switches, each of the plurality of packet switches has a storage means for storing a number of simultaneous call acceptance calls preset for each of the subscriber lines, A congestion state detecting means for detecting a state, and a call setting for performing a call setting or a call disconnection based on a comparison of the number of simultaneous call acceptance calls for a call on the subscriber line when the congestion state is detected. Control means, wherein the congestion state detection means determines a predetermined CC usage rate for a processor of a call processing department in order to determine a congestion state. And a threshold storage unit that stores a threshold value of the memory usage for the memory capacity is set a value and advance.

A congestion control method in a packet switching network according to the present invention includes a plurality of packet switches each accommodating a plurality of subscriber terminals or subscriber devices via a plurality of subscriber lines and connected via the network. In the packet switching network provided with, each of the plurality of packet switches stores in advance a number of simultaneous call acceptance calls preset for each of the subscriber lines in a storage means, and when a call is detected, an overloaded state of processing causes a congestion state. Is detected by the congestion state detection means, and when a congestion state is detected, the call setting control means performs call setting or call control on the basis of comparison of the detected call with the number of simultaneous call acceptance calls. And the congestion state detecting means performs C to the processor of the call processing section.
Detecting that the C usage rate exceeds a predetermined threshold value or that the memory usage rate for a predetermined memory capacity of the call processing department exceeds a predetermined threshold value, The called-side packet switch which has detected that the congestion has occurred due to the rate or the memory usage exceeding the preset threshold value is transmitted to the network by an autonomous message indicating that the congestion has occurred. To the maintenance center connected to the base station, and the maintenance center transmits, based on the reception of the autonomous message, the packet of the called side to all the calling side packet exchanges calling to the called side packet exchange. The switch transmits a command indicating that the switch is congested, and the calling-side packet switch receiving the command compares the number with its own number of simultaneously accepted calls, and If it is within the number of calls the call processing is performed by the call setting control means disconnects the call processing if I exceeds.

According to a congestion control method in a packet switching network according to the present invention, in a packet switching network having a plurality of packet switches connected via a network, the plurality of packet switches have a plurality of subscriber counts and an interface to the network. A plurality of line control units for controlling each line, a plurality of call control units connected to each of the plurality of line control units on a one-to-one basis for controlling call processing and detecting and controlling a congestion state; A node control unit that performs control, and a system bus that connects the plurality of call control units and the node control unit, wherein the plurality of call control units are subordinate for call setting and determination of the congestion state. Storing a simultaneous call accepting call preset for each of the plurality of subscriber lines connected to the line control unit; And a second storage unit for storing a predetermined CC usage threshold for the internal processor and a predetermined memory usage threshold for the internal packet memory capacity. I have.

[0022]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a system configuration diagram showing a packet switching network according to an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of a configuration of each packet switching device shown in FIG.

Referring to FIG. 1, a packet switching network according to the present embodiment includes a packet switch (hereinafter referred to as a switch) A2, a switch B3, a switch N4, a switch X5 and a network maintenance center 10 connected via a network 1, and a switch A2. , Exchange B3, exchange N4 and exchange X5 respectively have subscriber terminals A6, B7,
Subscriber terminal N8 and host computer (subscriber X)
9 are accommodated. In the packet switching network thus configured, each of the subscriber terminals A6, B7, N
8 communicates by calling a subscriber X9 using a number of logical channels. In the present embodiment, the number of simultaneous call acceptance calls is previously set to 2, 1, and 3 for the subscriber lines including the subscriber lines connected to the subscribers A6, B7, and N8.

In FIG. 2, a plurality of packet switches A2, B3, N connected via the network 1 shown in FIG.
A plurality of packet switches A2, B3, N4, and X5 in the packet switching network provided with a plurality of LCPs 4 and X5 respectively control a plurality of subscriber lines 1a and a plurality of line control units (LCPs) 14- which control each line as an interface to the network 1.
1 to 14-5 and the plurality of line control units 14-1 to 14-14.
-5, each of which is connected one-to-one to control call processing and detect and control the state of congestion (CCP).
13-1 to 13-5, a node control unit (NPC) 12 for performing node control, and a plurality of call control (CCP) 13-1 to 13-1
13-5 and a system bus 11 for connecting a node control unit (NCP) 12 with a plurality of call control units (CCP).
Each of 13-1 to 13-5 is a preset number of simultaneous call acceptance calls for each of a plurality of subscriber lines 1a connected to a subordinate line control unit for call setting and determination of a congestion state. And a second memory for storing a predetermined threshold of the CC usage rate for the internal processor and a predetermined threshold of the memory usage rate for the capacity of the internal packet memory. And a storage unit.

FIG. 3 is a flowchart showing a CCP congestion detection process of the packet switch in the present embodiment.
Is the CR of the CCP of the packet switch in the present embodiment.
FIG. 5 is a sequence diagram showing an operation of the present embodiment.

Next, the operation of the embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG.

It is assumed that the subscriber X9 shown in FIG. 1 is out of order or closed. In a normal state other than the congestion state, the subscriber terminals A6, B7, and N8 transmit a CR packet to set up a call with the subscriber X9 using a plurality of logical channels. Since the work is over, the call cannot be set, and the call is disconnected by the CI packet corresponding to the transmission of the CR packet. Subscribers A6, B7, N
In the case of No. 8, since the call setup could not be performed, the CR packet is transmitted again to perform the call setup using a large number of logical channels. You. The sequence at this time is shown in FIG.

In this way, the subscribers A6, B7, N8
Repeats call setup and call disconnection while packet switch X5
Packets are concentrated on the network and an overload occurs, resulting in congestion.

When detecting that the congestion has occurred due to the CC usage rate or the memory usage rate exceeding a preset threshold value, the packet switch X5 issues an autonomous message to the network maintenance center 10 to Notify maintenance personnel. When the maintenance person knows that the packet switch X5 is congested by an autonomous message, it notifies other packet switches A2, B3, and N4 in the network that the switch X5 is congested by a command from the network maintenance center 10.

At this time, the CCP of the packet switch X5
FIG. 3 shows a flow chart of the congestion detection process in FIG.
In the congestion detection process of the CCP 13 started periodically in FIG. 3, it is determined whether or not the CC usage rate for the CCP processor exceeds a threshold value (S11).
If it has exceeded, issue the autonomous message. Also,
If not, it is determined whether or not the memory usage rate for the memory capacity in the CCP exceeds a threshold value (S12). If it has exceeded (S12), an autonomous message issuance process is performed (S13). If it has not exceeded (S12), the congestion detection processing ends (S14). The autonomous message is notified to the network maintenance center 10.

In this way, the packet switches A2, B
3 and N4 are notified by a command from a maintenance person of the network maintenance center 10, and when congestion of the packet switch X5 is detected, the packet switches A2, B3,
LCP1 accommodating N4 subscriber terminals A6, B7, N8
In the call processing unit of the CCP 13 above the fourth, the number of accepted CR packets from the subscriber terminals A6, B7, N8 is limited in accordance with the number of call acceptance calls set in advance for each subscriber line.

At this time, the packet switches A2, B3, N
FIG. 4 shows a flowchart of the CR packet receiving process in the call processing unit of the CCP above the LCP that accommodates the four subscriber terminals A6, B7, and N8.

When a CR packet is received from each of the subscriber terminals A6, B7, N8, a CR packet receiving process is started. First, it is determined whether the network is congested (S
21) If congestion is occurring, it is determined whether the number of calls being set is within the number of call acceptance calls (S22). At this time, if it is within the number of accepted calls, the number of calls being set is incremented and a call setting process is performed (S23). If the number exceeds the number of accepted calls, a call disconnection process is performed (S25). If the call is not congested, the number of calls being set is incremented and a call setting process is performed (S2).
6).

FIG. 5 shows a sequence as a network at this time.

Since the number of accepted calls of the subscriber terminals A6, B7, N8 is 2, 1, and 3, respectively, the packet switch A
In the case of 2, B3 and N4, a CR packet which is a call setting request exceeding the number of call acceptance calls from the subscriber terminals A6, B7 and N8 is disconnected by a CI packet. For this reason, the call setting numbers of the subscriber terminals A6, B7, C8 are limited to 2, 1, and 3, respectively.

As a result, transmission of CR packets to the packet switch X5 is reduced, and packet concentration is prevented.

Further, even in a congested state, a call can be set for calls within the number of accepted calls.

As described above, in the present embodiment, the transmission of the CR packet to the destination packet switch X5 is restricted by limiting the number of call sets in the source packet switch A2, B3, N4 according to the number of call acceptance calls. By being restricted,
The packet switching network X5 can be prevented from being concentrated on the destination side packet switch X5, thereby preventing an overload state, and preventing the packet switch X5 from becoming congested due to overload. It is possible to prevent the entire system from becoming congested.

Further, even in a congested state, a call can be set for calls within the number of call acceptance calls, so that the service to the subscriber can be improved even in a congested state.

[0041]

As described above, according to the present invention, a packet containing a plurality of subscriber terminals or subscriber units via a plurality of subscriber lines and having a plurality of packet exchanges connected via a network is provided. In the switching network, each of the packet switches has a storage unit for storing the number of simultaneous call acceptance calls preset for each subscriber line, a congestion state detection unit for detecting a congestion state from an overload state of processing, and a congestion state. Is provided with call setting control means for setting or disconnecting a call on the subscriber line based on a comparison with the number of simultaneous call acceptance calls when a call is detected.

The first effect is that packets are not concentrated on the destination packet switch, and an overload state can be prevented.

The reason is that the transmission of packets to the destination packet switch is restricted by limiting the number of call settings in the calling packet switch according to the number of incoming calls.

The second effect is an extension of the first effect described above. By preventing the destination packet switch from becoming congested due to overload, the entire packet switching network becomes congested. Can be prevented.

The third effect is that the service to the subscriber can be improved even in a congested state.

The reason is that, even in a congested state, calls can be set for calls within the number of call acceptance calls.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing a packet switching network according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an example of a configuration of each packet switch shown in FIG.

FIG. 3 shows a CCP of the packet switch in the present embodiment.
9 is a flowchart showing a congestion detection process of FIG.

FIG. 4 is a CCP of the packet switch in the present embodiment.
9 is a flowchart showing a CR packet receiving process of FIG.

FIG. 5 is a sequence diagram showing an operation of the present embodiment.

FIG. 6 is a block diagram showing a second conventional packet switching network.

FIG. 7 is a block diagram showing a third conventional packet switching network.

FIG. 8 is a diagram showing an operation sequence of the third conventional example of FIG. 7;

[Explanation of symbols]

 Reference Signs List 1 network 1a subscriber line 2 packet switch (switch) A 3 packet switch (switch) B 4 packet switch (switch) N 5 packet switch (switch) X 6 subscriber terminal A 7 subscriber terminal B 8 subscriber terminal N 9 Host computer (subscriber X) 10 Network maintenance center 11 System bus 12 Node control unit (NCP) 13-1 to 13-5 Call control unit (CCP) 14-1 to 14-5 Line control unit (LCP)

Claims (7)

[Claims] 1. A packet switching network, comprising a plurality of packet switches each accommodating a plurality of subscriber terminals or subscriber units via a plurality of subscriber lines and connected via a network. Each of the exchanges is a storage means for storing the number of simultaneous call acceptance calls preset for each subscriber line, a congestion state detection means for detecting a congestion state from the processing overload state,
Call setting control means for performing a call setting or a call disconnection based on a comparison with the number of simultaneous call acceptance calls for a call on the subscriber line when the congestion state is detected. A congestion control method in a packet switching network. 2. The congestion state detecting means, for determining a congestion state, determines a threshold value of a predetermined CC usage rate for a processor of a call processing department and a threshold value of a memory usage rate for a predetermined memory capacity. 2. The apparatus according to claim 1, further comprising threshold value storage means for storing a threshold value.
Congestion control method in the packet-switched network as described. 3. A packet switching network, comprising a plurality of packet switches each accommodating a plurality of subscriber terminals or subscriber units via a plurality of subscriber lines and connected via a network. In each of the exchanges, the number of simultaneous call acceptance calls preset for each subscriber line is stored in advance in a storage means, and when a call is detected, a congestion state detection means detects a congestion state from an overload state of processing, and In the packet switching network, when a state is detected, the call setting control means performs call setting or call control based on a comparison of the detected call with the number of simultaneous call acceptance calls. Congestion control method. 4. The congestion state detecting means, wherein the CC usage rate for a processor of a call processing department exceeds a predetermined threshold value or the memory usage rate for a predetermined memory capacity of the call processing department is reduced. 4. The congestion control method in a packet switching network according to claim 3, wherein the congestion state is detected when it is detected that a predetermined threshold value is exceeded. 5. The called packet switch which has detected that the CC usage rate or the memory usage rate has exceeded the preset threshold value and has entered a congestion state has entered the congestion state. An autonomous message indicating that the autonomous message is transmitted to a maintenance center connected to the network, and based on the reception of the autonomous message, the maintenance center transmits all the calling side packets to the called side packet switch. 5. The congestion control method in a packet switching network according to claim 3, wherein a command indicating that the called packet switch is congested is transmitted to the switch. 6. The calling-side packet switch receiving the command compares the number of its own simultaneous call accepting calls with its own. If the number is within the number of simultaneous call accepting calls, the call processing is performed. 6. A congestion control method in a packet-switched network according to claim 3, wherein a disconnection process is performed by said call setting control means. 7. In a packet switching network comprising a plurality of packet switches connected via a network, said plurality of packet switches correspond to a plurality of subscriber counts and a plurality of lines for controlling each line by interfacing with said network. A control unit, a plurality of call control units connected one-to-one to each of the plurality of line control units to control call processing and detect and control a congestion state, a node control unit to perform node control, A call control unit and a system bus connecting between the node control units, wherein the plurality of call control units are connected to the plurality of line control units connected thereunder for call setting and determination of the congestion state. A first storage unit for storing a preset simultaneous call acceptance call for each of the subscriber lines, and a predetermined CC usage for an internal processor; A second storage unit for storing a threshold value of a usage rate and a predetermined threshold value of a memory usage rate for an internal packet memory capacity.