JPS6359297B2 - - 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 method on 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 line usage for outgoing and incoming calls;
If the number of lines in use exceeds a predetermined threshold, the number of free lines is reserved for the other party, and if the call volume in one direction increases and the number of lines in use in one direction increases, the number of lines used in one direction increases. Since the lines were reserved for calls in the other direction, calls in the other direction were prioritized (protected) and drawbacks such as pressure on calls in the other direction were eliminated. Prior Art and Problems In the conventional two-way line selection method, for example, if an outgoing call includes an important call from a public institution, news organization, etc., the outgoing call is prioritized when the number of incoming calls increases and the line becomes congested. Important calls are also given priority, but important calls cannot be given priority over outgoing general calls. Furthermore, when the number of outgoing calls increases and the line becomes congested, the priority of outgoing calls becomes lower than that of incoming calls, and therefore the priority of important calls also becomes lower. For this reason, priority cannot always be given to important calls, and the call loss rate for important calls increases, making it difficult to ensure communication of important calls. The same problem occurs when the incoming calls include important 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 incoming and outgoing general calls, but dividing the line can significantly reduce the line efficiency or cause the line to be used for important calls and general calls. The disadvantage is that the flexibility regarding Purpose of the Invention In order to eliminate these drawbacks, the present invention, in addition to the previous invention of Japanese Patent Application No. 115526/1984, provides a method to alleviate the traffic pressure between general calls by reserving lines for important calls. The purpose of this system is to provide an important call communication method on a bidirectional line in which important calls are prioritized under any circumstances. In the bidirectional line selection that merges the lines in the direction of The number of reserved lines of zero or more is set in advance, the number of bidirectional lines in use in the first direction and the second direction of the two-way line is monitored, and the number of bidirectional lines in use in the first direction is set in advance. If it is smaller than the number of reserved lines in the first direction, the general call in the first direction seizes the two-way line only when the number of free lines on the two-way line is greater than the number of lines reserved for the important call. , if the number of bidirectional lines in use in the first direction is greater than or equal to the number of reserved/stopped lines in the first direction, the general call in the first direction has the number of free lines in the two-way line reserved for the important call. seizing the bidirectional line only when the sum of the number and the number of lines reserved in the second direction is greater than the sum of the number and the number of reserved lines in the second direction, and each important call in the first direction and the second direction always seizes the bidirectional line. It is characterized by: 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, and 5 and 6 are exchanges 1 and 2. 7 is a bidirectional line, and 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. 1st
Tables (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. 115526/1983.

[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 allowed to seize the bidirectional line 7 (even if it is allowed, 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, for an incoming call
The main Rb line will be reserved. In the case of an incoming call, the processing of the exchange 2 is similarly as shown in (B) of Table 1. There is no particular distinction between important outgoing calls and incoming calls, and they have been treated in the same way as general calls. 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 shown in (A) of Table 2.
The processing of the exchange 2 regarding an incoming call is in accordance with (B) of Table 2. The processing of the exchange 1 regarding outgoing calls is performed under the conditions of X>Rc when a<La, and when a≧La for general calls.
When , line acquisition is permitted under the condition of X>Rb+Rc. The processing of the exchange 2 regarding incoming calls is performed under the conditions of X>Rc when b<Lb and b≧Rc for general calls.
When Lb, line capture is permitted under the condition of X>Ra+Rc. For important outgoing and incoming calls, both exchanges 1 and 2 are permitted to seize the line unconditionally. As can be seen from Table 2 (A) and (B), general calls are allowed to seize the line under the condition that at least X > Rc, and important calls are allowed to seize the line unconditionally, so they are always important. Rc lines will be reserved for the call. The number of outgoing calls increases and the line becomes congested,
When a≧La, line capture is permitted under the condition of X>Rb+Rc, so for important calls and incoming general calls,
This means that the Rb+Rc main line is reserved. At this time, the incoming general call is compressed and normally b < Lb, so the incoming general call can use the reserved line in the range of X > Rc, and the incoming general call has priority over the incoming general call, The pressure on incoming general calls can be alleviated. Conversely, the same applies when the number of incoming calls increases, and the pressure on outgoing general calls can be alleviated. However, incoming and outgoing general calls are
>Because of the Rc condition, important calls are given the highest priority.
Therefore, if the number of outgoing calls increases, the priority will be incoming/outgoing important calls > general incoming calls > general outgoing calls, and if incoming calls increase, the priority will be incoming/outgoing important calls > general outgoing calls > general incoming calls. In addition, if both outgoing and incoming calls increase, the number of lines used for outgoing and incoming calls will be almost equal to the design conditions, so outgoing and incoming important calls will be greater than general outgoing calls and general incoming calls, and in either case, important calls will have priority. It turns out that it will be done. The number of lines reserved for important calls, Rc, is usually 1 or more, but it is also possible to include Rc=0. In this case, in Table 2
If Rc=0, the logic for general calls is the same as in Table 1, and for important calls, line capture is permitted unconditionally, which is the same as in Table 2. Therefore, the number of outgoing calls increases and Rb lines are reserved for incoming calls, but important outgoing calls can also seize these lines, so important outgoing calls have the same priority as incoming calls. . Conversely, even when the number of incoming calls increases, incoming important calls also have the same priority as outgoing calls. Therefore, the priority of the important call is the same as the higher priority of the outgoing and incoming general calls, and although the degree of priority is lower than when Rc≠0, communication of the important call can be ensured. Also, in the above explanation, it is assumed that important calls are prioritized for both outgoing and incoming calls, but for example, there may be cases where only outgoing important calls are given priority, and incoming important calls are given the same priority as incoming general calls. In such a case, the exchange 2 may 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 used 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 will increase the degree of priority (protection), but the efficiency of the line will decrease, so they should be kept to the minimum necessary. Although the present invention can be realized by 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.
1, 12, 13, 14, 15, 16 are inputs, 2
1, 22, 23, 24, 25 are registers, 26 is an adder, 27, 28, 29 are comparators, 30 is OR
The circuits 41, 42, 43, 44, 45, and 46 are outputs. The case of exchange 1 will be explained. Register 21 receives Rb via input 11, register 22 receives Rc via input 12, and register 2
3 receives X via input 13, register 24 receives a via input 14, and register 25 receives input 1.
5 are set by the central processing unit 5, respectively. Adder 26 adds the contents of registers 21 and 22, and outputs Rb+Rc at output 44. When a line capture request occurs due to a general call, the central processing unit 5
applies a drive pulse to input 16. The drive pulse of input 16 causes comparator 27 to register register 24 (La).
and the contents of the register 25(a), and when a<La, a pulse is output to the output 42, and when a≧La, a pulse is output to the output 43. When a<La, the output 42 drives the comparator 29, and the comparator 29 drives the register 23.
(X) and the contents of register 22 (Rc),
A pulse is output to the output 46 only when >Rc.
On the other hand, when a≧La, the output 43 causes the comparator 28
is driven, and the comparator 28 is connected to the adder 26 (Rb+
Rc) and register 23 (X), X>Rb
A pulse is output to output 45 only when +Rc.
The OR circuit 30 takes the OR logic of the outputs 45 and 46 and outputs it to the output 41. A pulse is output to the output 41 when the conditions shown in Table 2 (A) are satisfied,
Indicates line seizure permission. The central processing unit 5 can read the output 41 at a certain timing and know whether or not the line acquisition is permitted. Note that in the case of an important call, the central processing unit 5 attempts to seize the line unconditionally. The contents of register 23 (X) and register 25 (a) are constantly updated as lines are captured and released, but register 21 (Rb), register 22 (Rc), and register 24 (La) only need to be set once. . but,
Registers 21, 22, etc. depending on the traffic situation etc.
It is also possible to change the contents of 24, for example, by a maintenance person using an input device attached to the central processing unit 5. The above explanation is
This is related to the exchange 1, but the same applies to the exchange 2, and the register 21, register 24,
The only difference is that Ra, Lb, and b are each set in the register 25. When the two-way line 7 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 only when the bidirectional line 7 is congested.
You may also use In the above description, the line between two exchanges has been described, but by relaying the identification signal of an important call using, for example, a common line signaling system, it becomes possible to give priority to important calls and communicate through the exchange network. Effects of the Invention As explained above, in the present invention, important calls are always reserved, so that important calls are given the highest priority, and even if the call volume in one direction increases, there is no pressure on general calls in the other direction. It has the feature of alleviating the Also,
Since the control is based on line reservation, there is no reduction in line efficiency unlike line splitting, and there is no loss of flexibility between general calls and important calls.

[Brief explanation of drawings]

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... input, 21, 22, 23, 2
4, 25...Register, 26...Adder, 27,
28, 29... Comparator, 30... OR circuit, 4
1, 42, 43, 44, 45, 46...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 the number of lines reserved for important calls of zero or more is set in advance, the number of bidirectional lines used in the selected directions of the first direction and the second direction of the two-way line is monitored, and the number of lines reserved for the two-way line in the first direction is set in advance. The number of uses is the first
, the general call in the first direction seizes the two-way line only when the number of free lines on the two-way line is greater than the number of lines reserved for the important call. 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, the number of idle lines in the two-way lines in the first direction is equal to the number of lines reserved for important calls. The bidirectional line is seized only when the number of reserved lines in the second direction is greater than the sum, and each important call in the first direction and the second direction always seizes the two-way line. An important call communication method for two-way lines.