JP2613228B2 - Logic session dynamic switching control method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching control method of a central processing unit in an information processing system, and particularly to an operation of a terminal device when configuring a network system. The present invention relates to a control method that enables switching.

[Conventional technology]

2. Description of the Related Art In recent years, in an information processing system having a network system configuration, a method of setting a communication environment without stopping the entire information processing system is disclosed in Japanese Patent Application Laid-Open No. 61-139858.

[Problems to be solved by the invention]

Regarding the conventional technology, the technology described in Japanese Patent Application Laid-Open No. 61-139858 is added by stopping only the relevant communication management program without stopping the entire information processing system when the communication environment is added or changed.・ We are trying to deal with the change. Therefore, although it is intended to partially execute system generation, the switching control of the connection destination in a network system configuration in which the communication control device is connected to a plurality of central processing units is not described. Not disclosed.

By the way, as the configuration of the information processing system becomes larger and more complex, the demand for calculation in a plurality of central processing units increases.
Methods to address processing demands are becoming more common. In such an information processing system having a network system configuration including a plurality of central processing units, a communication control unit, and a terminal unit, more efficient operation (power saving operation) by further reducing power consumption is required. Becomes More specifically, in the case of late night hours or holidays when the load on the information processing system is low, several of the central processing unit groups are stopped, and when the load is high, the central processing units are restarted to meet the processing demand. It is desirable. However, using a terminal device, a time sharing system (Time Sharing System: TS
For users who use the information processing system for S) or online processing, the service of the information processing system must not be degraded. Specifically, when the user uses the central processing unit of A in the TSS, the user
A central processing unit must operate a log-off command (LOGOFF) and then log on to B's central processing unit (LOGON command). That is, it is only necessary to receive the service of another central processing unit without forcing the operation of the terminal user.

Accordingly, an object of the present invention is to provide a central processing unit that is used without forcing a terminal user to operate in an information processing system having a network system configuration including a central processing unit group, a communication control unit, and a terminal group. Is to provide a control method for automatically switching between the two.

[Means for solving the problem]

The above-mentioned object is a communication control device (CCP) connected to a plurality of central processing units.
A storage area for storing the history of message transactions corresponding to each terminal device, a control block indicating which central processing device each terminal device is using, and a central processing unit connected to the communication control device. A control block for the device identification information, the state of the central processing unit, and alternate central processing unit identification information is provided to constantly trace message transactions with each terminal device, and to issue command commands from the terminal device and the central processing unit. Control means for storing an end message from the storage area. When switching to the replacement central processing unit is instructed from the outside, the terminal device that used the central processing unit before the switching is selected, and the information in the history storage area of the previous message transaction is used. First, a command (LOGOFF command) for disconnecting the logical session of the terminal is sent to the central processing unit before switching, and then a command (LOGON command) for opening a logical session to the replacement central processing unit is sent to the central processing unit. After automatically sending to the replacement central processing unit, a command message for continuously using the terminal device is automatically generated based on the transaction history stored in the history storage area. This is achieved by providing control means for sending to the central processing unit.

As described above, the switching of the central processing unit to be used is achieved without forcing the user of the terminal device to input a command sequence.

[Action]

The logical session dynamic switching control method according to the present invention is provided in a communication control device existing between a terminal device and a central processing unit, stores a history of message transactions, and later switches the central processing unit. Since a control method of automatically sending a command message to the central processing unit is sometimes employed, the conventional operability is not impaired.

〔Example〕

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

FIG. 1 is a diagram briefly showing a dynamic session dynamic switching control system of the present invention. FIG. 1 shows a communication control unit CCP200 for a plurality of central processing units (CPU-A, CPU-B) 201 and 202;
And a terminal device group 204 to form a network configuration. The central processing units CPU-A and CPU-B are also connected to the file device 203.

Within the central processing unit groups CPU-A and CPU-B, an operating system (OS) and a communication management program (Virtual Teleprocessing Access Methood: VTA)
M), the TSS control programs 208 and 209 operate, and the application programs AP ₁ and AP ₃ correspond to the terminal devices 206 and 207.
Will work. For details of the communication management program, refer to the following publications.

"VOS3 ECS / VTAM Explanation: Document No. 8090-3-140: Hitachi, Ltd." Communication Control Processor (CC)
In the P) 200, a network control program (NCP) 211 for controlling a network transmission procedure is operating, and an HDLC (High-level Data Lin
k Control) procedure and SDLC (Synchronous Data Link Control)
ol) Transmission control of the procedure is performed. For details on this communication procedure, see “Synchronous Data Link Control: A Perspect
ive: IBM Systems Journal, vol. 13, No. 2, 1974 ".

In the above configuration, the terminal device 206 is
200 through via a line l200 or line L201, a central processing unit CPU-A201, CPU-B202 will be freely accessible, it is possible to operate the application program AP ₁ ~AP _4. As described above, the terminal device 206 and the like are connected to the communication control device CCP20.
A state in which the application program in the central processing unit CPU-A201 is operated through 0 is generally referred to as "a logical session has been opened". Therefore, as in the above example, the terminal device
When 206 is using AP _1, the terminal device 206 will have been opened a TSS control program 208 and the logical Setsushiyon of the central processing unit CPU-A 201.

The logical session dynamic switching control method of the present invention is realized by a management table group 210, data, stream control processing program 220, and command interpretation / execution program 230 in the communication control device CCP200. Then, the outline of the logical session dynamic switching control method of the present invention will be described with reference to FIG. 1, and then the details of the configuration and operation will be described with reference to FIGS.

Referring to FIG. 1, the user of the terminal device 206 is
TSS control program in CPU-A201 via CPU
Suppose you have opened a logical session with 208. At this time, the AP ₁ is a processing program for the TSS command input by the user of the terminal device 206. Here, the central processing unit CPU-A
It is only necessary to stop 201 and automatically transfer the TSS user of the central processing unit CPU-A201 to the central processing unit CPU-B202. Therefore, the logic session dynamic switching control method of the present invention is effective.

For batch processing, the central processing unit CPU-A201
If the service on the side is stopped, the subsequent batch processing is automatically executed by the central processing unit CPU-B202. This is possible because the file device 203 is connected to both the central processing units CPU-A and CPU-B.

The data stream control program 220 stores, in the management table group 210, transaction histories of messages with the central processing unit corresponding to the terminal device. The management table group 210 includes, in addition to the message transaction history, a central processing unit state management table indicating the state of the connected central processing unit, an application / program processing central processing unit correspondence management table, A terminal status management table and a message buffer are included. These management tables will be described later with reference to FIGS.

The command interpreting / executing program 230 shown in FIG.
11 operates when command data issued from is received via the line l203. Details of the operation are shown in FIGS. 11 to 14.

The command interpreting / executing program interprets the command data from the command device 205, stores control information based on the command data in the management table group 210, and, together with the data stream control program 220, executes the operation of the logical session of the present invention. The real switching control method is realized.

Established logical Setsushiyon between the terminal device 206 and the TSS control program 208 of the central processing unit CPU-A 201, when running the TSS command AP _1, disabling the central processing unit CPU-A 201 from the command device 205 Is issued,
The command interpreting / executing program 230 turns off the valid flag of the entry in the central processing unit status management table (see FIG. 3) in the management table group 210. As a result, the logical session cannot be opened with the TSS control program 208 of the central processing unit CPU-A 201 thereafter.

Next, when a command of “switch execution” is issued from the command device 205, the command interpretation / execution program 230 is executed together with the data stream control program 220 and the management table group 210.
, A terminal device group 20 that has established a logical session with the TSS control program in the central processing unit CPU-A201.
A command (LOGOFF command) for separating 4 is automatically generated, stored in a message buffer, and then passed to the network control program NCP211. The network control program NCP211 sends command data in the message buffer to the central processing unit CPU-A201 via the line l200. As a result, the command data is transferred to the TSS control program 208 via the communication management program VTAM, the session of the terminal device is closed, and the logical session is separated.

Next, using the message transaction history stored by the data stream control program 220 for each terminal device first, the central processing unit status management table,
TSS control program 209 in alternate central processing unit CPU-B202
Command to open a logical session with (LO
GON command) is automatically generated and the message / buffer is stored, and then control is passed to the network control program LNCP211. With this, the network control program
The NCP 211 sends the command data in the message buffer to the central processing unit CPU-B202 via the line l201. When the command data is passed to the TSS control program 209 via the communication control program VTAM, the session of the terminal device is opened, and the AP ₃ becomes operable thereafter.

If the logical session is opened in another central processing unit, the command interpreting / executing program 230 and the data stream control program 220 sequentially execute a message buffer using the previously stored message transaction history. Stores command data. As a result, the terminal device has been restored to a state immediately before the central processing unit is switched, and it becomes possible to input commands from the terminal device thereafter.

By performing the above processing on all the terminal devices connected to the central processing unit to be switched, the logical session is automatically switched. For details of LOGON command, LOGOFF command, and other TSS commands,
See the following publications:

"VOS3 TSS Command: Document No. 8090-3-936: Hitachi, Ltd." Next, the configuration and operation of the logic session dynamic switching control method of the present invention will be described with reference to FIGS. I will do it.

FIG. 2 shows the configuration of the management table group 210, the data stream control program 220, and the command interpretation / execution program 230 shown in FIG. The management table group 210, a central processing unit status management table CPUTAB212, application cases Chillon program processing CPU correspondence management table APLTBL213, terminal status management table DEVT214, Metsuseji-A transaction history table MSGLG _n 215, and Metsuseji-buffer 216 is there. Note that the message history table MSGLG _n 215 exists for each terminal device.

The data stream control program 220 includes a main processing program 221 and a logical session opening processing program section 2.
22, a message transmission / reception processing program section 223 and a logical session termination processing program section 224, and have a structure called from the command interpretation / execution program 230. Also, the dotted arrows in FIG. 2 indicate that the processing program group refers to and updates the management table group 210.

FIG. 3 shows the configuration of the central processing unit status management table CPUTAB212. The number of valid entries in the table is indicated by the entry number NOCPU241. Reference numeral 240 denotes an R flag for indicating that a command has been issued from the command device 205. Each entry is the CPU name CPUI
D242, a valid flag (V flag) 243, and a replacement central processing unit name CHNGCPU244. This CPUID242, CHNGCPU2
44 is the central processing unit identification information. Note that the CHNG CPU 244 is valid when the V flag 243 is off.

FIG. 4 shows the configuration of an application program processing central processing unit correspondence management table APLTBL213.
As in FIG. 3, the number of valid entries in the table is indicated by the number of entries NOENT246. Each entry has an application program name APLID247 and a corresponding central processing unit name CPUID248. This management table indicates on which central processing unit the application program, for example, the TSS control program can run.

FIG. 5 shows the configuration of the terminal state management table 214 and the message transaction history tables MSGLG ₁ to _n 215 and the correspondence between the two management tables. In the terminal state management table DEVT214, the number of terminal devices registered in the table is indicated by the number of entries n251. Each entry is composed of an active flag (A flag) 252, a connection central processing name 253, and an address MSGLGA254 of the message transaction history table 215, and occupies one entry corresponding to the terminal device.

Message transaction history table MSGLG ₁ ~
_n 215 is a header section 256 storing control information, the number of command message histories m257, the current entry
Pointer CURENT258, next entry pointer 25
9 and a command message history area 260.

FIG. 6 is an operation flow chart of the main processing program section 221 of the data stream control program 220 shown in FIG. 2, FIG. 7 is an operation flow chart of the logical session opening processing program section, and FIG. 8 is a message buffer 216. LOG in
FIG. 9 is an explanatory diagram when an ON command data stream is stored, FIG. 9 is an operation flow diagram of a message transmission / reception processing program unit, and FIG. 10 is an operation flow diagram of a logical session end processing program unit.

FIG. 11 shows a command interpretation / command from the command device 205 shown in FIG.
Indicates the type of command to the execution program 230,
14 are operation flowcharts of the command interpretation / execution program 230.

Now, the operation of the logical session dynamic switching control system of the present invention will be described in detail with reference to FIGS.

Referring to FIG. 6, the main processing program 221 in the data stream control program 220 shown in FIG. 2 is used when a message is exchanged between the terminal device 206 and the central processing units CPU-A and CPU-B. It works without fail. First,
In the determination process 1, it is checked whether or not a request from the command device 205 has been received. This checks the R flag 240 in the central processing unit status management table 212 shown in FIG. This R flag 24
If 0 is on, the command interpretation / execution processing program 230 is executed, and this processing will be described later with reference to FIG. 11 and subsequent figures.

If the R flag 240 is off, processing 2 and subsequent steps are executed. First, the terminal state management table DEVT214 is searched, and an entry corresponding to the terminal device is located.
Then, the data stream in the message buffer 216 is checked to check the LOGON command message. ▼ LOGON ▼ If it is a command message, the control is passed to the logical session opening processing program section 222 to open the logical session. If it is not a LOGON command message, a check 4 is performed to check the LOGOFF command message. ▼ LOGOFF ▼ If it is a command message, control is passed to the logical session end processing program unit 224 to end the logical session.

If it is not a LOGOFF command or message, control is passed to the message transmission / reception processing program unit 223 to collect the message transaction history of the terminal device.

FIG. 7 shows an operation flow of the logical session opening processing program section 222. In process 6, the application program processing central processing unit correspondence management table APLTBL213 in FIG. 4 is searched, and the message / message shown in FIG.
An entry having the same value as the value of the APLID field 262 in the buffer 216 is searched, and the CPUID 248 is obtained. Next, in process 7,
The central processing unit status management table CPUTAB242 is searched, and an entry equal to the CPUID 248 obtained in the process 6 is located.

In the determination process 8, it is checked whether or not the V flag 243 of the entry is on. C if V flag 243 is on
The PUID 242 is stored in the APLID field 262 in FIG. On the other hand, if the V flag 243 is off, it means that the use of the central processing unit is prohibited, and the CHNG CPU 244 is set to APLI.
Store in D-field 262. FIG. 8 shows processes 6 to 6 in FIG.
This shows the relationship between 10 and the message buffer 216. The value obtained by the processing method of the present invention is stored in the APLID field 262 in the data stream of the LOGON command. Therefore, the value stored in the APLID field 262 is the same as the value of the TSS control program 208 or the TSS control program 208 shown in FIG.
This means that the control program 209 is uniquely specified.
Naturally, when the terminal user does not designate the APLID field 262, the processing 6 of FIG. 7 is executed using the CPU 253 in the terminal state management table 214. In this case, the terminal attempts to establish a logical session with the central processing unit previously used.

Referring again to FIG. 7, in process 11, after turning on the A flag of the terminal state management table DEVT214,
The value obtained in processing 9 or processing 10 is stored in the CPU field 253.

Process 12 is the message transaction history table
This is the initialization processing of MSGLG _n 215, and the address of this area is M
Obtained from SGLGA254. First, the current entry pointer CURENT258 and the next entry pointer NXTENT259
Is initialized to the beginning of the storage area, and the contents of the message buffer 216 are stored in the area indicated by the current entry pointer CURENT 258. Next, next
After moving the entry pointer NXTENT259 forward, the number of histories m
+1 is added to 257. Thereafter, the content of the message buffer 216 is changed to the network control program N in the process 13 of FIG.
The data is sent to the corresponding central processing unit by the CP 211, and a logical session is opened.

FIG. 9 shows an operation flow of the message transmission / reception processing program section 223. First, in the determination process 16, it is checked whether the message is an input message from the terminal device. This distinction is clear when control is transferred from the network control program NCP211 to a processing program group that implements the logical session dynamic switching control method of the present invention (not shown).
If the input Metsuseji from the terminal apparatus will only be stored TSS command Metsuseji to manipulate resources of the computer system to continue to Metsuseji-A transaction history table MSGLG _n 215. The general TSS command and the user's own creation command are stored in the message transaction history table MSGLG _n 215, and then the message of the end of the processing of the TSS command, for example, the 'READY' message is sent to the terminal device. When the data stream is output, the data stream of the previously stored general TSS command or user-created command is deleted from the history table 215. This deletion processing is a judgment processing 24 and a processing 25
It is done in. By performing such processing, it is not necessary to re-execute a general TSS command or the like for which processing has been completed after the logical session switching.

After the determination processing 17 and the determination processing 18, the data stream of the resource allocation command ▼ ALLOC ▼ command is processed by the processing 19 to the next entry pointer NXTE.
Store in the area indicated by NT259.

On the other hand, in the case of the 解除 FREE ▼ command which is a resource release command, the data stream is stored in the processing 22 through the determination processing 20 and the determination processing 21. Next, in process 23, the number of histories m25 in the message / transaction history table 216
7 is set to +1 and the current entry pointer CURENT25
8. Advance the next entry pointer NXTENT259 to the next storage area.

When the processing of the message transmission / reception processing program unit 223 is completed, a request for transmission / reception is sent to the network control program NCP 211 in processing 13 in FIG. 6 so that the data stream of the message buffer is transmitted to the central processing unit or the terminal device. Will be sent to

FIG. 10 is an operation flowchart of the logical session end processing program unit 224. The logical session termination process is
After turning off the A flag 252 in the terminal status management table 214 in the process 26, the M in the terminal status management table DEVT 214 is turned on in the process 27.
Current entry pointer CURENT258, next entry pointer NXTEN of the message transaction history table MSGLG _n 215 pointed to by SGLGA254
Initialize T259 and the number of records m257.

FIG. 11 shows a list of switching instruction commands from the instruction device 205. In FIG. 11, item numbers 1 to 3 correspond to the central processing unit status management table CPUTAB212 shown in FIG.
Is a correction instruction for each entry. Item No. 4 is an instruction of “execution of switching”. Item Nos. 5 and 6 are correction instructions for each entry of the terminal status management table DEVT214 shown in FIG. Item Nos. 7 and 8 are the application program processing central processing unit correspondence management tables AP shown in FIG.
This is a correction instruction for each entry of the LTBL213.

12 to 14 show the operation flow of the command interpretation / execution program 230 corresponding to each instruction shown in FIG. In FIGS. 12 to 14, except for the “switch execution” (“TRSFR” command) of item No. 4 shown in FIG. 11, after correcting the corresponding entry in each management table, Turn off 240.

FIG. 13 and FIG. 14 are flowcharts of the operation of “execute switching”. Referring to FIG. 13, after the repetition count i is initialized in the process 32, an entry in which the V flag 243 of the central processing unit status management table CPUTAB212 is off is searched in the processes 33 to 35. If the count i exceeds the entry number NOCPU 241 in the determination processing, the R flag 240
Turn off and exit.

When an entry with the V flag 243 turned off is detected, the count j is initialized to search the terminal state management table 214 next. Thereafter, the processing j from the processing 38 to the processing 54 is counted.
Repeat until the value exceeds.

In the process 40, the j-th entry of the terminal status management table DEVT214 is located, and in the judgment process 41, it is checked whether the A flag 252 is on. If the A flag 252 is off, the terminal device is in an unused state, and the process returns to step 38 to prepare for locating the next entry.

If the A flag 252 is ON, it is checked in the determination process 42 whether the central processing unit used by the terminal device is marked as invalid. If it is not equal to the identification information CPUID242 of the central processing unit marked as invalid, the process returns to the processing 38.

On the other hand, if the central processing unit marked invalid is used, the process of “switch execution” is continued after the process 43. First, the message transaction history table MSGL pointed to by MSGA254 in the entry
G _n 215 is copied to the work area, and in the subsequent processing, the data of this work area is used. Of course,
Logical session termination processing program section 224 called from command interpretation / execution program 230, message transmission / reception processing program section 223, logical session opening processing program section
At 222, the original message transaction history table MSGLG _n 215 is used.

When the preparation is completed in the process 43, the control is passed to the logical session end processing program unit 224, and the logical session of the terminal device is terminated. For this purpose, the process 224 is called after the data stream of LOGOFF is stored in the message buffer 216. Next, in a process 45, a request to transfer the contents of the message buffer 216 to the network control program NCP 211 to the central processing unit is issued.

Next, the process proceeds to a process 46 in FIG. 14, and the command and the command in the message transaction history table copied to the work area are read.
Preparations are made to transmit data strings to the central processing unit sequentially.

The transfer of the command message to the central processing unit may be performed by repeating steps 47 to 54.

First, the count k is incremented by one in a process 47, and then a determination process 48 is performed.
The number of histories in the work area is compared with the number m, and if it exceeds the value of m, the process returns to the processing 38 in FIG. 13, which means that the switching of the logical session of the terminal device has been completed.

In a process 49, the k-th data stream is extracted and stored in the message buffer 216. Judgment process 50
Then, it is checked whether the data stream is a LOGON ▼ command data stream. If the result of the check indicates that the data stream is a LOGON command, the APLID field (FIG. 8) in the message buffer 216 is replaced with the replacement central processing unit name CHNGCPU 244 obtained in the process 37. afterwards,
The control is transferred to the logical session opening processing program section 222, and the original message transaction history table 21 is returned.
After storing the history information in 5, the processing 52 requests the network control program NCP 211 to transfer a message to the central processing unit. As a result, the central processing unit designated by the replacement central processing unit name CHNGCPU244, that is, the first central processing unit,
A logical session is established with the TSS control program 209 of the CPU-B 202 shown in FIG. Thus, switching of the central processing unit has been performed.

On the other hand, as a result of the check in the judgment processing 50, if the data stream is not the data stream of the LOGON command, that is, if it is the command data stream of the TSS after the establishment of the logical session, the control is transferred to the message transmission / reception processing program section 223, and the original message is sent.・ Transaction history table 21
After storing the history information in 5, the processing 52 requests the network control program NCP 211 to transfer a message to the central processing unit.

After waiting for the response of the TSS command transmitted in the process 53, the control is transferred again to the message transmission / reception processing program unit 223, and then the network control program NCP211 is requested to transfer the message to the terminal device.

Thereafter, the process returns to the process 47, and the processes 47 to 54 are repeated until the copied TSS command sequence of the message transaction history in the work area disappears, thereby completing the automatic switching of the logical session of the terminal device. Also processing
By repeating the processing from step 38, the switching of the logical session of all the terminal devices using the central processing unit designated as invalid is completed.

In the embodiment disclosed herein, the switching instruction and the like are issued by the instruction device 205, but these are not limited. The command may be issued from the central processing unit.

〔The invention's effect〕

As described above, according to the present invention, the history of the message transaction corresponding to each terminal device is stored in the communication control device connected to the plurality of central processing units, and when the central processing unit is switched, the central processing unit is switched. The control means for automatically sending the stored message transaction to the device is provided, so that the central processing unit to be used can be automatically switched without forcing the terminal user to perform any operation. is there.

[Brief description of the drawings]

FIG. 1 is a diagram simply showing a logical session dynamic switching control system of the present invention, FIG. 2 is a configuration diagram of a control program group and a management table group for realizing the control system of the present invention, and FIG. FIG. 4 shows the contents of the application program processing central processing unit correspondence management table, and FIG. 5 shows the contents of the terminal state management table and the message transaction history table. FIG. 6 is an operation flow diagram of the main processing program unit, FIG. 7 is an operation flow diagram of the logical session opening processing program unit, and FIG. 8 is a LOGON command in the message buffer 216 of FIG. FIG. 9 is an explanatory diagram when the data stream is stored, FIG. 9 is an operation flow diagram of the message transmission / reception processing program unit, and FIG. 10 is a logical session termination process. FIG. 11 is a diagram showing the types of commands from the command device 205 shown in FIG. 1 to the command interpreting / executing program unit, and FIGS. 12 to 14 are command interpreting / executing commands. It is an operation | movement flowchart of a program. 200: communication control device, 205: command device, 206: terminal device, 201, 202: central processing unit, 210: management table group, 211: network control program, 220: data stream control program, 230 ... Command interpretation / execution program.

Claims (2)

(57) [Claims] In a network system configuration in which a terminal device group is connected to a plurality of central processing device groups via at least one communication control device, the communication device located between the terminal device group and the central processing device group. First storage means for storing a transaction history of a message corresponding to each terminal device in the control device, identification information of a central processing unit connected to the communication control device, and whether or not the central processing device is usable. A second storage means for storing the identifier to be indicated and the identification information of the replacement central processing unit, and a logic between the first central processing unit when the usable identifier of the first central processing unit is marked as unusable. The transaction history of a group of terminals that have been temporarily connected is retrieved from the first storage means, and a command message for disconnecting a logical connection from the first central processing unit is automatically generated to generate a first message. After transmission to the processing device, a logical connection relationship is automatically established with the alternate second central processing device stored in the second storage means, and based on the transaction history retrieved earlier. A logical session dynamic switching control method, comprising: a first control means for automatically generating a command message for continuously using the terminal and transmitting the command message to a second central processing unit. 2. A second control means for setting control information of said second storage means based on a command from a control device connected to said communication control device separately from a terminal group or said central processing device group. 2. The dynamic session dynamic switching control method according to claim 1, further comprising: