JP3249613B2 - Transmission control method for ISDN terminal device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission control method for an ISDN terminal device using an ISDN as a transmission path and having a transmission function of a frame mode bearer service.

[0002]

2. Description of the Related Art There is a frame mode bearer service as one of methods for realizing high-speed packet switching mode data transmission using ISDN as a transmission path. In this frame mode bearer service, call control such as call setup is performed by D
The multiplexing of calls and the identification of calls are performed in Layer 2 while being performed in channels, thereby reducing intra-network processing and enabling high-speed data transmission.

When a congestion state is detected, for example, when a frame is lost, explicit congestion notification information defined in a layer 2 frame is set so that the terminal can perform congestion control. I have to.

When the terminal sets explicit congestion notification information in a received frame, for example, the CC
ITT Recommendation Q. Congestion control procedure specified in 922 (recommended algorithm; hereinafter, referred to as recommended congestion control procedure)
In order to eliminate the congestion state.

[0005]

However, in such a conventional method, it is not possible to know whether the congestion is detected by the partner terminal or the network, and the explicit congestion notification information is set. The terminal that received the frame executed the recommended congestion control procedure regardless of the target of the congestion detection.

For this reason, when the terminal detects congestion, there is a possibility that a situation may occur in which the congestion state cannot be efficiently eliminated.

The present invention has been made in view of such circumstances, and has as its object to provide a transmission control method for an ISDN terminal device that can appropriately eliminate a congestion detection state.

[0008]

SUMMARY OF THE INVENTION The present invention provides a transmission control method for an ISDN terminal device using an ISDN as a transmission path and having a function of transmitting a frame mode bearer service. Information indicating that the generation source of the congestion notification information is a terminal is added and transmitted to the partner terminal.

In addition, in the transmission control method of an ISDN terminal device using ISDN as a transmission path and having a transmission function of a frame mode bearer service, a source of explicit congestion notification information is generated when the own terminal detects congestion. Is transmitted to the partner terminal while adding information indicating that the frame is the one to which the explicit congestion notification information is added, and the source of the explicit congestion notification information is the terminal. When the information notifying the fact is added, a predetermined congestion control procedure unique to the terminal is started.

In addition, in a transmission control method for an ISDN terminal device using ISDN as a transmission path and having a transmission function of a frame mode bearer service, information on a congestion control procedure is exchanged with a partner terminal, and When congestion is detected, the source of the explicit congestion notification information is added to the information indicating that it is a terminal, and sent to the other terminal, while the frame to which the explicit congestion notification information is added is received, and When the information for notifying that the source of the explicit congestion notification information is the terminal is added to the frame, the congestion control procedure notified from the partner terminal is started.

[0011] Further, in the transmission control method of an ISDN terminal device using ISDN as a transmission path and having a transmission function of a frame mode bearer service, when the own terminal detects congestion, the source of the explicit congestion notification information is the terminal. Is transmitted to the destination terminal with the information indicating that the forward explicit congestion notification information is added, and the source of the forward explicit congestion notification information is added to the frame. When information for notifying that the terminal is a terminal is added, a predetermined terminal-specific congestion control procedure is started, and a source of reverse explicit congestion notification information and reverse explicit congestion notification information is added to a transmission frame. Is information that indicates that the terminal is a terminal.

[0012]

Therefore, since the terminal can notify the other terminal that the congestion state has been detected, a congestion control procedure suitable for the terminal can be executed, and the congestion state can be efficiently eliminated. Further, by exchanging information on the congestion control procedure in advance, the congestion control procedure according to the device function of each terminal can be performed, and the congestion state can be more appropriately eliminated.

[0013]

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

FIG. 1 shows a group 4 facsimile apparatus according to one embodiment of the present invention.

In FIG. 1, a control section 1 mainly performs control processing of each section of the group 4 facsimile apparatus, and a system memory 2 executes a control processing program executed by the control section 1 and a processing program. In addition to storing various data and the like necessary when performing the operation, the work area of the control unit 1 is configured, and the parameter memory 3 stores various information unique to the group 4 facsimile apparatus. .

The scanner 4 is for reading an original image at a predetermined resolution, the plotter 5 is for recording and outputting an image at a predetermined resolution, and the operation display unit 6 is a facsimile apparatus. To operate,
It consists of various operation keys and various indicators.

The encoding / decoding section 7 encodes and compresses the image signal and decodes the encoded and compressed image information into the original image signal.
This is for storing a large number of image information in a coded and compressed state.

The ISDN interface circuit 9 connects the group 4 facsimile apparatus to the ISDN and integrates the signal processing function of the layer 1 and the integration of the signal of the D channel (signal channel) and the signal of the two B channels (information channels). It has a separation function, and the D-channel transmission control unit 10 controls the ISD
This is for performing signal processing on the N D channels, and the B channel transmission control units 11 and 12 are for realizing a group 4 facsimile transmission procedure function performed on the B channel. The D-channel transmission control unit 10 and the B-channel transmission control units 11 and 12 also have a processing function of a frame mode bearer service.

The control unit 1, the system memory 2,
Parameter memory 3, scanner 4, plotter 5, operation display unit 6, encoding / decoding unit 7, image storage device 8, D-channel transmission control unit, and B-channel transmission control units 11, 1.
2 is connected to a system bus 13, and data exchange between these elements is mainly performed through the system bus 13.

The group 4 facsimile apparatus of this embodiment exchanges data of the frame mode bearer service by using the frame of the format shown in FIG. This frame format is basically a frame of the frame mode bearer service. In this embodiment, the fourth, third and second bits of the first octet of the information field include parameters PA, PB and PDE relating to congestion notification. Is used.

Here, the frame shown in FIG. 2 is a frame of the frame mode bearer service of the frame switch when the address field is 2 octets, and the fourth bit of the second octet of the address field contains the frame. The forward explicit congestion notification information FECN for notifying that congestion has occurred in the transfer direction has a third bit in the reverse direction for notifying that congestion has occurred in the reverse direction to the frame transfer direction. Explicit congestion notification information B
In the second bit of the ECN, discardable display information DE for indicating that this frame can be discarded at the time of congestion is defined.

The parameters PA, PB, PDE
Are forward explicit congestion notification information FECN, backward explicit congestion notification information BECN, and discardable display information D, respectively.
E is used as information indicating that the terminal has added it.

For example, when the terminal detects congestion of a transmission frame during data transmission in the frame mode bearer service, the terminal sets forward congestion notification information FECN to data 1 and sets parameter PA to data 1.

[0024] The other terminal transmits the forward congestion notification information FECN.
When a frame having data 1 set in parameter PA is received, it is determined that the terminal is in a congestion state, and a congestion control procedure unique to the terminal is started.

On the other hand, the other terminal transmits the forward congestion notification information F
When a frame in which only ECN is set to data 1 is received, it is determined that the network is in a congestion state,
Start the recommended congestion control procedure.

Here, the congestion control procedure can be basically conceived of a method of gradually lowering the data transfer rate, a method of gradually reducing the number of outstandings, and a method combining these. In the terminal-specific congestion control procedure, the width of the stepwise change is set adaptively according to the data transmission functions such as the size of the transmission buffer, the size of the reception buffer, and the transfer rate capability of the terminal. Good to do.

Further, prior to data transmission, the above-mentioned functions related to data transmission are exchanged between terminals, and the conditions of the terminal-specific congestion control procedure used at the time of data transmission are determined. Can be performed. Prior to data transmission, a congestion control procedure to be used may be negotiated between terminals.

FIG. 3 shows an example of a process executed when transmitting a transmission frame.

First, it is checked whether or not the congestion is detected at that time (decision 101). If the result of decision 101 is YES, data 1 is set to the parameter PA of the data of the first octet of the information field. At the same time, data 0 is set in the parameters PB and PDE (process 102).

Next, a transmission frame is formed (Step 10).
3) Transmit the frame (process 104). Note that the frame formed in the process 103 is a frame of the above-described format. When the own terminal has detected congestion, the forward explicit congestion notification information FECN is set to data 1, and the other terminal detects congestion. If so, reverse explicit congestion notification information BECN is set in data 1.

If the result of decision 101 is NO, it is checked whether or not the forward congestion notification information FECN of the frame received from the partner terminal is set to data 1 (decision 104). The result of decision 104 is YES
, The parameter P of the received frame
It is checked whether data 1 is set in A (decision 105).

When the result of the determination 105 is YES, it means that the other terminal is in the congestion detection state.
Data 0 is set in the parameter PA of the data of the first octet of the information field, data 1 is set in the parameter PB, and data 0 is set in the parameter PDE (process 106). The process proceeds to process 103, where a transmission frame is formed and transmitted.

When the result of the judgment 104 is NO, the congestion is not detected, and when the result of the judgment 105 is NO, the network is in the state of congestion detection. , PB, PD
Data 0 is set in E (process 107), and process 103
Then, a transmission frame is formed and transmitted.

FIG. 4 shows an example of processing when starting the congestion control processing.

First, it is checked whether the forward explicit congestion notification information FECN of the received frame is set to data 1 (decision 201). If the result of decision 201 is YES, the parameter PA is set to data 1 A check is made to determine whether or not it has been performed (determination 202).

When the result of the decision 202 is YES, it is checked whether or not the congestion control procedure is designated by the partner terminal (decision 203). When the result of the decision 203 is YES, the congestion control procedure designated by the partner terminal is determined. The process of the procedure is started (process 204). When the result of the determination 203 is NO, the processing of the congestion control procedure set in the own terminal is started (processing 205).

When the result of the determination 202 is NO, it means that the network has detected congestion, so that a process of a predetermined recommended congestion control procedure is started (process 206). Also, judgment 20
When the result of 1 is NO, this process is immediately terminated.

In this way, when data 1 is set in the forward explicit congestion notification information FECN of the frame received from the partner terminal and data 1 is set in the parameter PA, the transmission frame Is set to data 1 in the backward explicit congestion notification information BECN, and data 1 is set to the parameter PB, and a terminal-specific congestion control procedure is started. The start can be detected, and the state can be shifted to the congestion control procedure state.

In the above-described embodiment, the case where the present invention is applied to the frame mode bearer service of the frame switch has been described. However, the present invention can be similarly applied to the frame mode bearer service of the frame relay. it can. Further, the above-described parameters can be defined in an address field or a control field.

In the above-described embodiment, the case where the present invention is applied to a group 4 facsimile apparatus has been described. However, the present invention is similarly applied to other terminal apparatuses using a frame mode bearer service. be able to.

[0041]

As described above, according to the present invention,
Since the terminal side can notify the other terminal that the congestion state has been detected, it is possible to execute a congestion control procedure suitable for the terminal, and it is possible to efficiently eliminate the congestion state. Also,
By exchanging information on the congestion control procedure in advance, it is possible to execute the congestion control procedure according to the device function of each terminal, and it is possible to obtain an effect that the congestion state can be appropriately eliminated.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a group 4 facsimile apparatus according to one embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of a frame format used in the embodiment.

FIG. 3 is a flowchart showing an example of processing when transmitting a frame.

FIG. 4 is a flowchart showing a processing example at the time of activation of a congestion control procedure.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04L 29/08 H04L 12/02

Claims (4)

(57) [Claims] 1. A transmission control method for an ISDN terminal device using an ISDN as a transmission path and having a transmission function of a frame mode bearer service, wherein when an own terminal detects congestion, a source of explicit congestion notification information is transmitted to the terminal. A transmission control method for an ISDN terminal device, characterized by adding information indicating that the transmission is complete and transmitting the information to a partner terminal. 2. A transmission control method for an ISDN terminal device using an ISDN as a transmission path and having a transmission function of a frame mode bearer service, wherein, when the own terminal detects congestion, the source of the explicit congestion notification information is the terminal Is transmitted to the destination terminal with information indicating that the frame has been added, while receiving the frame with the explicit congestion notification information added,
In addition, when information indicating that the source of the explicit congestion notification information is a terminal is added to the frame, a predetermined congestion control procedure specific to the terminal is started. Control method. 3. A transmission control method for an ISDN terminal device using an ISDN as a transmission path and having a transmission function of a frame mode bearer service, comprising: exchanging information on a congestion control procedure with a partner terminal; When detecting congestion, while adding information indicating that the source of the explicit congestion notification information is a terminal and sending it to the partner terminal, receiving the frame with the explicit congestion notification information added,
And an ISDN terminal device for starting a congestion control procedure notified from a partner terminal when information indicating that the source of the explicit congestion notification information is a terminal is added to the frame. Transmission control method. 4. A transmission control method for an ISDN terminal device using an ISDN as a transmission path and having a transmission function of a frame mode bearer service, wherein when a self terminal detects congestion, a source of the explicit congestion notification information is a terminal. Is transmitted to the destination terminal with the information indicating that the forward explicit congestion notification information is added, and the source of the forward explicit congestion notification information is added to the frame. When information for notifying that the terminal is a terminal is added, a predetermined terminal-specific congestion control procedure is started, and a source of reverse explicit congestion notification information and reverse explicit congestion notification information is added to a transmission frame. Characterized by adding information indicating that the terminal is a terminal.
Transmission control method for N terminal devices.