JPS6359298B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD OF THE INVENTION The present invention relates to a bidirectional line in a circuit switched network such as a telephone switched network, a data switched network, and a facsimile switched network, in which general calls and important calls coexist. This invention relates to an important call communication system in a bidirectional line that alleviates pressure and ensures communication of important calls. Background of the Technology In circuit-switched networks, bidirectional circuits that merge circuits in a first direction and a second direction, e.g. It has the advantage of being able to use lines more efficiently than unidirectional lines in each direction. However, since the line is commonly used for outgoing and incoming calls, if the call volume for either outgoing or incoming calls increases more than the designed call volume, that call will occupy more of the two-way line than the designed value, causing calls in the other direction to This has the disadvantage that communication is strained, or both the originating and receiving parties compete for the line, resulting in double capture of the line, leading to invalid switching operations. In order to eliminate this drawback, we first applied for patent application No. 54-115526.
proposed a selection control method for bidirectional lines. This method counts the number of lines in use for outgoing and incoming calls, and if each number of lines in use exceeds a predetermined threshold, the number of available lines is reserved for the other party. When the call volume in one direction increases and the number of lines used in one direction increases, the line is reserved for calls in the other direction, so calls in the other direction are prioritized (protected).
This eliminates drawbacks such as pressure on calls in other directions. Prior Art and Problems In the conventional two-way line selection method, for example, if the outgoing call includes an important call from a public institution or news organization, the outgoing call is prioritized when the number of incoming calls increases and the line becomes congested. Therefore, important calls are also given priority, but they cannot be given higher priority than outgoing general calls. Conversely, when the number of outgoing calls increases and the line becomes congested, incoming calls are given priority over outgoing calls, and important calls included in the outgoing calls also have lower priority. In such cases, outgoing important calls must be given priority over outgoing general calls.
Moreover, since the line is congested due to outgoing calls, a system is desired in which important outgoing calls can be given lower priority than incoming calls. On the other hand, when the line is congested, there is a plan to divide the line into one for important calls and one for general calls, but dividing the line may cause a significant drop in line efficiency, or the line usage for important calls and general calls may be affected. The disadvantage is that flexibility is lost. Purpose of the Invention In order to eliminate these drawbacks, the present invention, in addition to the previous explanation of Japanese Patent Application No. 115526/1983, has provided a system for reserving traffic lines for important calls under certain conditions to reduce traffic pressure between general calls. The purpose of this system is to provide an important call communication system on a bidirectional line that can alleviate the problem and give priority to important calls over general calls in that direction. In the bidirectional line selection by merging the lines in the first direction and the second direction, the number of line reservations and the number of reserved suspensions for the first direction and the second direction of the bidirectional line, and the important The number of reserved lines for calls is set in advance, the number of bidirectional line usages in the selected directions of the first direction and the second direction of the two-way line is monitored, and the number of bidirectional line usages in the first direction is set in advance. If it is smaller than the number of reserved stops in the direction of 1,
General calls in the first direction capture the number of bidirectional lines only when the number of free lines in the two-way lines is greater than the number of reserved lines for important calls, and important calls in the first direction are unconditionally captured. capture the two-way line,
If the number of bidirectional lines in use in the first direction is greater than or equal to the number of reserved lines in the first direction, for general calls in the first direction, the number of idle lines in the two-way lines is equal to the number of lines reserved for important calls. The bidirectional line is seized only when the number of free lines in the two-way line is greater than the sum of the number of reserved lines in the second direction, and the important call in the first direction is made when the number of free lines in the two-way line is greater than the number of reserved lines in the second direction. This feature is characterized in that the bidirectional line is captured only when the value is larger than that. The drawings will be explained in detail below. Embodiment of the Invention FIG. 1 shows an embodiment in which the present invention is realized by hardware, in which 1 and 2 are exchanges, 3 and 4 are communication path devices of exchanges 1 and 2, respectively, and 5 and 6 are each Central processing units of exchanges 1 and 2, 7 is a bidirectional line,
8 and 9 are line selection devices related to the present invention. In this embodiment, a call from exchange 1 to exchange 2 will be referred to as an outgoing call, and a call from exchange 2 to exchange 1 will be referred to as an incoming call. Tables 1 (A) and (B) show the logic of line capture permission for outgoing calls and incoming calls according to the invention of Japanese Patent Application No. 115526/1982.

[Table] In Table 1, a and b are the number of lines used for outgoing calls and incoming calls, La and Lb are the number of outgoing calls and incoming calls held and stopped, respectively.
Ra and Rb are the number of reserved lines for outgoing calls and incoming calls, X is the number of idle lines of the bidirectional line 7, and "-" means unconditional. Regarding an outgoing call from exchange 1 to exchange 2, the processing of exchange 1 is as follows according to (A) in Table 1. When a<La, it is unconditionally permitted to seize the bidirectional line 7 (even if permission is granted, if X=0, the call will of course be lost). When a≧La, acquisition of the bidirectional line 7 is permitted only when the number of free lines X is X>Rb, and when X≦Rb, acquisition is prohibited. That is, when a≧La, Rb lines are reserved for incoming calls.
In the case of an incoming call, the processing of the exchange 2 is similarly as shown in Table 1 (B). In the above system, important calls such as outgoing calls and incoming calls are treated as general calls without any particular distinction. Tables 2 (A) and (B) show the line capture permission logic for each type of outgoing call and incoming call according to the present invention. Here, Rc is the number of lines reserved for important calls.

[Table] The processing of exchange 1 regarding outgoing calls is according to Table 2 (A), and the processing of exchange 2 regarding incoming calls is according to Table 2 (B).
In the process of the exchange 1 regarding an outgoing call, line acquisition is permitted for a general call under the condition that X>Rc when a<La, and under the condition that X>Rb+Rc when a≧La. An important outgoing call is unconditionally when a<La,
Furthermore, when a≧La, line acquisition is permitted under the condition that X>Rb. Therefore, when the number of outgoing calls increases and the two-way line 7 becomes congested, a≧La, so outgoing general calls are allowed to seize the line under the condition of The call is put on hold. Furthermore, since line capture is permitted for outgoing important calls under the condition that X>Rb, Rb is reserved for incoming calls. Therefore, since incoming important calls are originally prioritized by reservation over incoming calls in general, a≧La.
Under the condition, the priority can be incoming important call>incoming general call>outgoing important call>outgoing general call. Conversely, when the number of incoming calls increases and the two-way line 7 becomes congested, normally a<La, X>Rc for outgoing general calls, and line seizure for outgoing important calls is permitted unconditionally.
Outgoing important calls have higher priority than outgoing general calls. At this time, b≧Lb, so line capture is permitted under the conditions of X>Ra+Rc for incoming general calls and X>Ra for incoming important calls, so outgoing calls have priority over incoming calls, and incoming important calls Calls are held and have priority over incoming general calls, so outgoing important calls>
The priority is: Outgoing general call > Incoming important call > Incoming general call. The above explanation is for the exchange 1, but the same applies to the exchange 2 as well. Furthermore, if both outgoing calls and incoming calls increase, the usage status of a and b will be the same as during the design load, so outgoing important calls, incoming important calls>outgoing general calls, incoming general calls. In the above explanation, it is assumed that both outgoing and incoming important calls are given priority. However, for example, there are cases where only outgoing important calls are given priority and incoming important calls are treated the same as incoming general calls. In this case, the exchange In the process, it is sufficient to treat all calls as general calls without distinguishing between general calls and important calls. An example of setting the parameter values of La, Lb, Ra, Rb, and Rc will be shown below. La and Lb should be about the average number of lines in use at the design call volume.If the number of bidirectional lines 7 is N and the design call volumes for outgoing and receiving calls are αa and αb, then LaN×αa/(αa+αb ), LbN×αb/
(αa+αb) may be used. However, La+Lb≧N. Ra, Rb, and Rc may be 2 to 3 lines at most, and usually 1 line. Increasing Ra, Rb, and Rc increases the degree of priority (protection), but the efficiency of the line decreases, so they should be kept to the minimum necessary. Although the present invention can be realized by the software of the central processing units 5 and 6, an example of the configuration of the line selection devices 8 and 9 when realized by hardware will be described below. FIG. 2 shows an example of the line selection device 8, with 11,1
2, 13, 14, 15, 16, 17 are inputs, 2
1, 22, 23, 24, 25 are registers, 26 is an adder, 27, 28, 29, 30 are comparators, 3
1, 32 are AND circuits, 33 are OR circuits, 41, 4
2, 43, 44, 45, 46, 47, 48, 49
is the output. The case of exchange 1 will be explained. The register 21 receives Rb via the input 11.
Rc is input to register 22 via input 12, X is input to register 23 via input 13, and register 2
4 is set to La via the input 14, and register 25 is set to a via the input 15 from the central processing unit 5. Adder 26 adds the contents of registers 21 and 22, and outputs Rb+Rc at output 44.
When a line acquisition request occurs, the central processing unit 5 applies a drive pulse to the input 16 and at the same time sets the input 17 to logic "1" in case of an important call. Comparator 27
register 24 by the drive pulse of input 16
(La) and the contents of register 25(a), a<La
When a≧La, the output is 42, and when a≧La, the output is 43.
Outputs a pulse to. When a<La, the comparator 29 is driven by the output 42, the comparator 29 compares the contents of the register 23 (X) and the register 22 (Rc), and outputs a pulse to the output 45 only when X>Rc. . The pulse of output 42 is logically ANDed with input 17 in AND circuit 32, and input 1 is output when there is an important call.
Since 7 is a logic "1", a pulse is output to the output 46 only in the case of an important call. On the other hand, when a≧La, a driving pulse is applied to the comparators 28 and 30 via the output 43, and the comparator 28 receives the register 23(X).
Compare the contents of the adder 26 (Rb+Rc) with X>
A pulse is output to the output 47 only when Rb+Rc. Comparator 30 compares register 23 (X) and register 21 (Rb) and outputs 4 only when X>Rb.
Outputs a pulse to 8. Output 48 is AND circuit 3
1 is ANDed with input 17, and a pulse is output at output 49 only in the case of an important call. Output 45,
46, 47, and 49 are ORed by an OR circuit 33 and output a pulse to an output 41. A pulse is output to the output 41 when the conditions shown in Table 2 (A) are satisfied, and this pulse indicates permission for line acquisition. The central processing unit 5 outputs the output 4 at a certain timing.
1 can be read to find out whether or not line capture is permitted. Register 23(X), Register 25(a)
The contents of register 21 (Rb) and register 22 are constantly updated as lines are captured and released.
(Rc) and the register 24 (La) need only be set once. However, it is also possible to change the contents of the registers 21, 22, and 24 depending on the traffic situation, for example, by a maintenance person using an input device attached to the central processing unit 5. The above explanation relates to exchange 1, but the same applies to exchange 2, and register 2
The only difference is that Ra, Lb, and b are set at 1, 24, and 25, respectively. When the bidirectional line is not congested, the quality is met as designed and there is no need to give priority to important calls, so the central processing unit 5 only has to seize the line without going through the line selection device 8. The line selection device 8 may be used only when the bidirectional line 7 is congested. In the above explanation, we have explained the line between two exchanges, but by relaying the identification signal of important calls using, for example, the common line signaling system, it becomes possible to communicate important calls with the exchange network with appropriate priority. . Effects of the Invention As explained above, the present invention can give priority to important calls on the compression side higher than general calls on the compression side and lower than calls in the other direction, and gives the highest priority to important calls on the pressured side. It has the feature of being able to give appropriate priority to important calls. Furthermore, since the control is based on line reservation, there is no reduction in line efficiency unlike line splitting, and flexibility between general calls and important calls is not impaired.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and FIG. 2 shows an example of a line selection device. 1, 2...exchange, 3, 4...communication path device,
5, 6...Central processing unit, 7...Bidirectional line,
8, 9... Line selection device, 11, 12, 13, 1
4, 15, 16, 17... input, 21, 22, 2
3, 24, 25... register, 26... adder,
27, 28, 29, 30...large/small comparator, 31,
32...AND circuit, 33...OR circuit, 41,4
2, 43, 44, 45, 46, 47, 48, 49
……output.

Claims (1)

[Claims] 1. In bidirectional line selection in which lines in the first direction and second direction are merged in a circuit switched network in which general calls and important calls coexist, selection of the first direction and the second direction of the bidirectional line, respectively. The number of line reservations and the number of reservation suspensions for the direction,
and set the number of reserved lines for important calls in advance.
The number of bidirectional lines in use in the selected direction in each of the first direction and the second direction of the two-way line is monitored, and if the number of bidirectional lines in use in the first direction is smaller than the number of reserved stops in the first direction; , the general call in the first direction seizes the two-way line only when the number of free lines in the two-way line is greater than the number of reserved lines for the important call, and the important call in the first direction is unconditionally seized. If the bidirectional line is acquired in the first direction and the number of bidirectional lines in use in the first direction is greater than or equal to the number of reserved outages in the first direction, the general call in the first direction is Only when the number of reserved lines for the important call and the number of reserved lines for the second direction is greater than the sum of the number of reserved lines for the second direction, the two-way line is seized, and the important call for the first direction An important call communication method in a bidirectional line, characterized in that the bidirectional line is seized only when the number of reserved lines in the second direction is larger.