Communication path selection system

[Detailed Description of the Invention]

[Outline important point] In an ATM exchange method etc., it wears from the Depart side switching node within the net, and chooses the course to a side switching node, While being related with the communication pathway alternative form for performing the call setup corresponding to the course, choosing the optimal path of the information between users that the block rate under communication becomes the minimum and attaining equivalent-ization of traffic within the net, In the communications network which consists of a plurality of switching nodes for the purpose of realizing the optimal call establishment procedures that make the minimum the overhead at the time of a call setup (delay), It has a channel selection node which carries out integrated management of the channel information in the communications network, and is a switching node from Recieved about A calling signal from Subscriber, The course inquiry message which wears with the discernment information on the above-mentioned from switching node to the above-mentioned channel selection node, and includes a member's discernment information and the demand amount of information is transmitted, and the course inquiry message is answered. It constitutes so that the call setup between the above-mentioned from member and the above-mentioned arrival member may be performed by the optimal path which stores the above-mentioned from switching node selected by the above-mentioned channel selection node, and the above-mentioned arrival member and which wears and connects a switching node. [Industrial Application] The present invention is worn from the Depart side switching node within the net in an ATM exchange method etc., chooses the course to a side switching node, and relates to the communication pathway alternative form for performing the call setup corresponding to the course. [Description of the Prior Art] Research of next-generation l5DN, i.e., broadband l5DN, for the full-scale utilization time of l5DN (Sir Beads synthesis digital M4) service coming around, and also treating a lot of information is also prospering. A T M especially Promising Vision of the method (asynchronous transfer mode; Asynchronous Transfer Mode) is most carried out as a data transfer method of broadband l5DN. ATM is the method which combined the strong point of a conventional packet exchange system and a circuit switching system. It has between terminals an advantage of a circuit switching system that data transfer of real time is possible in arbitrary communication bands (transmission speed and communication time), by an advantage of a packet exchange system that data transfer is possible, and high-speed repetition operation of a time slot unit. By ATM, a circuit is used by a time slot multiplex, and, specifically, a user puts and transmits the fixed-length (tens of bytes) packet called a cell to the vacant time slot on a circuit. Therefore, the user can change transmission speed arbitrarily by making the number of the cells transmitted per unit time fluctuate. And the header which stored the logical channel number for combining with an address terminal logically, the error correcting code, etc. is added to a cell. In the switchboard side, high-speed exchange of the cell inputted one after another per time slot is carried out in parallel per cell (time slot unit) with the time sharing switch of hardware based on the logical channel number in the header of each cell. With this, he leaves protocol control of error control / resending control, a flow control, etc. to a user terminal, and it uses an optical network as a transmission way. Such art enables it to transmit very efficiently various data of the range over a several bits-per-second~several 100M (Mega) bit / second in real time. However, in ATM, in order to employ efficiently the feature that the flexibility of a communication band is large, the problem how to match a resource within the net to a call setup demand arises. It is Based to the conventional Time Division Multiplexing (TDM) (a circuit switching system). Although the situation where communication is refused to a call setup demand (it is hereafter called a block) may occur since the course for wearing from Subscriber in the shortage of within-the-net resources, i.e., within the net, at the time of a call setup, and talking over the telephone to a member is occupied by other A call and they run short of them, - If a degree call setup is completed and a circuit is set up, the block of A call (communication) cannot arise during communication. On the other hand, in ATM, when a resource within the net is insufficient at the time of a call setup, a call setup demand is refused similarly, but the block of A call (communication) may be produced also in communication. This is a statistics multiplex type communication method with which ATM has variable zone nature. Since a user is a grade which applies for average access speed, for example at the time of a call setup, It is because the sum total of a zone of communication information from a member who communicates via a set-up circuit may exceed zone capacity of a circuit set up by burst (data should focus and transmitted in large quantities) etc.-like at the time of -. Since [ that it is such ] it receives inconvenient, the ATM switching system side requires the rapidity of exchange processing and the simplest possible protocol composition must be taken, it will discard and, as for the cell at the time of Pronk generating, user information will be lost. [Problem(s) to be Solved by the Invention] Therefore, if in charge of realizing statistics multiplex type communication methods, such as an ATM method, a roux Ting method with which the block rate an opening/not only closure of a mere circuit but under communication becomes the minimum is needed at the time of the channel selection (it is [ roux Ting and the following ] the same) of a net. It is necessary to provide the procedure for setting up A call the optimal between each switching node (shot side switchboard-transit exchange - wearing side switchboard) on the optimal call establishment procedures to each roux Ting, i.e., the selected course. An object of the present invention is to choose the optimal path of the information between users that the block rate under communication becomes the minimum, and to attain equivalent-ization of traffic within the net, and to realize the optimal call establishment procedures that make the minimum the overhead at the time of a call setup (delay). [Means for solving problem] Drawing 1 is a block diagram of the present invention. the present invention -- a plurality of switching node 2+, 2z and 23, and ... it is premised on communications network 1 which consists of 27. The line 1 is A T M, for example. It is broadband l5DN by a method (asynchronous transfer mode; Asynchronous Transfer Mode). The present invention has first channel selection node 5 which carries out integrated management of the channel information in communications network 1. The channel information between each switching node is managed intensively, the means being connected to each switching node 2in communication WIl+, and 22.23, ..., 2n, for example via a common line signal network, and delivering and receiving a control signal to each of these nodes and mutual. And in the present invention, course inquiry message 6 which switching node 21 from Recieved wears A calling signal from Subscriber 3 to the above-mentioned channel selection node 5 with the discernment information on the above-mentioned from switching node 2I, and includes member's 4 discernment information and the demand amount of information is transmitted. In channel selection node 5, the optimal path which answers this, wears with The originating switching node 2., and stores member 4 and which wears and connects 2 n of switching nodes is determined, and it wears with member 3 from a basis companion to this optimal path, and performs the call setup between members 4. In order to realize the above-mentioned control action, the following operations are specifically performed. First, channel selection node 5 corresponds to the optimal path answered and chosen as course inquiry message 6, The channel information which consists of discernment information on each switching node which wears and exists between the discernment information on switching node 21, and the node and The originating switching node 2I is returned to The originating switching node 21 based on the discernment information on The originating switching node 2I contained in course inquiry message 6. In The originating switching node 2I, the switching node which should be connected to the next based on the received channel information is distinguished, the circuit to the node is chosen, and the call setup signal which includes channel information to the node is transmitted. In the following switching node which received the call setup signal including the channel information, the call setup signal which distinguishes the switching node which should be connected to the next like the above based on the received channel information, chooses the circuit to the node, and includes the above-mentioned channel information to the node is transmitted. Hereinafter, wear by repeating the above-mentioned operation by each switching node, and each circuit corresponding to the optimal path is set up to 2n of switching nodes, and it wears with Subscriber 3 and performs the call setup between members 4. Channel selection node 5 is provided with the following. A route candidate extracting means which wears from The originating switching node 21 and extracts at least one course candidate to 2n of switching nodes based on course inquiry message 6 transmitted, for example from two dishes of The originating switching node in order to determine the optimal path, An optimal path selecting means as which each of this course candidate's usage rate chooses the minimum course candidate as the optimal path. An optimal path selecting means is each link 2between each switching node in communication M41+, for example. 22.21 The amount recognition memory measure of present [ used ] which carries out recognition memory of the amount of present [ used ] of each circuit corresponding to 23, ..., etc., Each usage rate of each circuit corresponding to each link between a maximum bulk store means to memorize the maximum capacity of each of this circuit, and each switching node in each above-mentioned course candidate, The usage rate calculating means corresponding to the link which adds the above-mentioned demand amount of information added to the amount of present [ used ] of each above-mentioned circuit at course inquiry message 6, and calculates the aggregate value as a rate produced by doing division by the maximum capacity of each corresponding above-mentioned circuit, It comprises a usage rate calculating means corresponding to the course which calculates each above-mentioned course candidate's usage rate as the greatest thing among each above-mentioned usage rate of each circuit corresponding to each link between each above-mentioned switching node within each above-mentioned course which can be found by the usage rate calculating means corresponding to the above-mentioned link. In an optimal path selecting means, when there are multiple courses of the minimum [ usage rate / above-mentioned ], the above-mentioned optimal path is determined based on the priority defined beforehand, for example. [For Work ] Channel selection node 5 carries out integrated management of the information about the channel selection between each switching node, It wears with The originating switching node 21 that the block rate under communication becomes the minimum, and the optimal path between switching nodes 2n is chosen, in communications network 1, based on the above-mentioned optimal path, it wears with Subscriber 3 and a call setup is performed among members 4. Thereby, equivalent-ization of traffic within the net can be attained. As call establishment procedures, channel selection node 5 returns The originating switching node 2. channel information, with it wears from "F all switching node 2I first, and is to 2n of switching nodes, In each switching node, the call setup signal which distinguishes the switching node which should be connected to the next based on the received channel information, chooses the circuit to the node, and includes the above-mentioned channel information to the node is transmitted, transmitting channel information and a call setup signal one by one. As it wears, each circuit corresponding to the optimal path to 2n of switching nodes is set up one by one by this and the overhead at the time of a call setup (delay) becomes the minimum, it wears with Subscriber 3 and the call setup between members 4 is made.

[example] Hereinafter, a detailed description of the invention is carried out, referring to drawings. Drawing 2 is the whole communications network lineblock diagram in this example. As shown in the figure, a communications network comprises communication-of-information network 7 and common line signal network 10. Here, as an example of a communications network, it is A T M. There is broadband l5DN by a method (asynchronoustransfer mode; Asynchronous Transfer Mode). In Drawing 2, communication-of-information network 7 comprises a plurality of switching node B, b, c, and d. Each of these switching nodes are switchboards which exchange communication information arbitrarily and it connects between a plurality of ON circuits and a plurality of appearance circuits. Although the following explanation explains communication-of-information network 7 which consists only of an expedient top and the four above-mentioned switching nodes, it may be made to comprise further many natural switching nodes in fact. In the above-mentioned communication-of-information network 7, it is accommodated, for example in switching node d with Subscriber (shot user) 8 stored in switching node a, and wears, and member (wearing user) 9 is, It communicates via one of a plurality of communication pathways connected via a plurality of relay switching node b which connects switching node a and switching node d, c, etc. Common line signal mi with control information different from communication of information y47 delivered and received between each switching node a -d on the other hand. It is Through(ed) and transmitted. Common line signal network 10 comprises a plurality of common line relay node 111~11. Channel selection node (DB node) 12 is connected to each switching node a -d via the above-mentioned common line signal 110. The node is a node which manages intensively the channel information between each switching node in communication-of-information network 7. The composition of switching node a of Drawing 2 is shown in Drawing 3. A plurality of member 13+'=131 * (Subscriber 8 of Drawing 2 is also one of them) is stored in switching node a, and it is A calling signal from each member, It is taken into central processing unit (CPU) 15 after being received by subscriber line signal apparatus (SSE) 141~14. provided in the circuit correspondence which stores this each member. Predetermined exchange processing is performed based on each above-mentioned A calling signal, and the connected state of telephone call way switch (SW) 16 is controlled by CPU15. In this case, each processed data are processed while operation of writing or read-out is performed at any time to the predetermined field on storage device (MEM) 17. The output of 5W16 is connected with each switching node [ of Drawing 2 ] b, c, etc. as circuit a-b between nodes, a-C, etc. The common line from common line signal network 10 of Drawing 2 is connected to CPU15 via common line signal apparatus (C3E) 18. Next, it has the composition as switching node a also with same composition of switching node d of Drawing 2. On the other hand, in the case of the example of Drawing 2, switching node b and c are switching nodes only for relay which do not store a member, and that of this composition are the same with the composition except the portion of dashed line 19 of Drawing 3. In this case, circuit a-b between nodes from switching node a etc., a-c, etc. input into the input side of 5W16. Switching nodes b and C may turn into a node which stores the same member as switching nodes a and d etc. Drawing 4 is a lineblock diagram of channel selection node 12 of Drawing 2. It is managed by CPU20, bus 21 is passed CPU20, and operations of the whole node are C3E22, MEM23, and database Memoryf. 24 is connected. The common line from common line signal [ of Drawing 2 ] 'lA10 is connected to C3E22. DB24 is memory storage which remembers that each channel information between each switching node [ of Drawing 2 ] a, b, c, and d mentions below, for example, is constituted by the disk store. Operation of the example of the composition of figure~figure 4 of above 2nd is explained below. This example explains the case where the connection demand of as opposed to [ wear and ] member 9 stored in switching node d from Subscriber 8 stored in switching node a of Drawing 2 as an example occurs. And it roughly divides and operation of this example consists of channel selection processing in channel selection node 12 of Drawing 2.4, and call setup processing between each switching node corresponding to the selected optimal path. First, as overall operation, the following explanation explains the call setup processing between each switching node, and the cut treating of the A call concerned, and explains the release processing accompanying the channel selection processing and the - above-mentioned cut treating in channel selection node 12 after it. First, it explains about call setup processing using the timing chart of the explanatory view of Drawing 5 of operation, and Drawing 6 of operation. When you want for introduction and Subscriber 8 to wear and to communicate with member 9, Subscriber 8 is, A layer number (for example, r045-201-9222J) and request speed (for example, 6 Mb/s (megabit per second)) information are added to A calling signal like ■ of Drawings 5 or 6, and it transmits to switching node a (hereafter referred to as The originating switching node a) which stores Subscriber 8. Here, request speed information is information for applying for whether he would like to wear and to communicate with the transfer rate of which grade generally among members 9. After CPU15 of Drawing 3 receives [ The originating switching nodea ] the above-mentioned signal via 5SE14, in order to search for the optimal path to switching node d (it wears and hereafter referred to as switching node d) in which it wears and member 9 is stored, Like 5th [ The ] figure ■, a course inquiry message is transmitted from C3E18 of Drawing 3 to channel selection node 12 via common line signal network 10. Under the present circumstances, the discernment signal which shows the identification number "shot PC=a" of request speed information "6 Mb/s" layer number r045-201-9222J and The originating switching node a and a course inquiry is added to the message like 6th [ The ] figure ■. After CPU20 receives the above-mentioned signal via C3E22 of Drawing 4 in channel selection node 12, Request speed information r6 Mb/s J contained in the above-mentioned course inquiry message, The optimal path is chosen by processing explained in full detail after the identification number "shot PC=a" of layer number r045-201-9222J and The originating switching node a, and a course inquiry response message is returned to The originating switching node a via common line signal mlO like 5th [ The ] figure ■ from C3E22 of Drawing 4. Channel information is added to the discernment signal which shows a course inquiry response to the message as shown in 6th [ The ] figure ■. If CPU15 of Drawing 3 receives the above-mentioned course inquiry response message via C3E18 in The originating switching nodea, First, the information on the head of the channel information included in the message "it is based on relay PC=p, and after catching one out of the circuit group between nodes which goes to relay node p from self-node a, 5W16 (refer to the 3rd figure) is controlled, and the caught circuit is connected with Subscriber 8 (refer to the 2nd figure). In the example of Drawing 2, although two switching nodes of b and C for relay are examples, they are explained on the facilities of explanation in Drawings 5 and 6 that wear with The originating switching node a and two or more relay switching node p, q, r, and ... exist between switching node d. Next, CPU15 of The originating switching node a (Drawing 3), The information which he used among channel information "what deleted relay PC""PJ is made into new channel information, the channel information is added to address signal and layer number r045-2019222 J, and it transmits to relay switching node p like 6th [ The ] figure ■. Specifically, it is transmitted to relay switching node p via common line signal network 10 like 5th [ The ] figure ■ from C3E1B of Drawing 3. Outgoing call reception is made like 6th [ The ] figure ■ from The originating switching nodea after the above-mentioned processing to Subscriber 8. Specifically, CPU15 of Drawing 3 carries out via 5SE14. If CPU in the node receives the above-mentioned address signal etc. via C3E (refer to the 3rd figure) in relay switching node P, First, the information on the head of the channel information included in the response "after catching one based on relay PC=qJ out of the circuit group between nodes which goes to relay switching node q from self-node p, SW (refer to the 3rd figure) is controlled, and an ON side circuit and the caught circuit are connected. Next, the information which he used among channel information "what deleted relay PC=qJ is made into new channel information, the channel information is added to an address signal (it is [ the following containing a layer number ] the same) etc., and it transmits to relay switching node q like 6th [ The ] figure ■. Specifically, it is transmitted to relay switching node q via common line signal W110 like 5th [ The ] figure ■ from C3E in a relay no dollar (refer to the 3rd figure). Hereinafter, by each relay switching node shown by each channel information, sequential execution of the same processing is carried out, it is worn, and call setup processing to switching node d is performed. Therefore, channel information is lost, when the channel information added to an address signal etc. decreases at a time to one, it wears and switching node d receives an address signal etc., whenever it progresses to the relay switching node of one beyond. Thereby, efficient call setup processing is possible. After an address signal's etc. wearing as mentioned above and reaching switching node d, the usual Call processing procedure and the same procedure are performed. That is, based on the received layer number, it wears first with an address signal, and the circuit to member 9 is caught, it wears, and receipt to member 9 is performed like Drawing 5 or 6th [ The ] figure ■. Then, it wears and address completion signal ACM is returned from switching node d like 6th [ The ] figure ■ to The originating switching nodea via each relay switching node. Then, it will wear, and if it wears, it wears from member 9 and a response is made by switching node d like 6th [ The ] figure ■, as shown in Drawing 6 [phase], reply signal ANM will be returned from switching node d to The originating switching nodea via each relay switching node. Thereby, a response is made by Subscriber 8 like 6th [ The ] figure ■ from The originating switching nodea. With the above Call processing procedure, it wears with Subscriber 8, communication becomes possible among members 9, and communication is performed like 6th [ The ] figure @. Next, the case where Subscriber 8 makes a cutting demand is explained as an example about processing in case the member under communication cuts A call. First, when Subscriber 8 makes a cutting demand like Drawing 5 or 6th [ The ] figure @, it is at The originating switching nodea, Identification number pc=a of one shot of The originating switching node a after CPU15 of Drawing 3 receives the above-mentioned signal via 5SE14", The channel information received as a course inquiry response message at the time of request speed information'6 Mb/s J and Calling is added to the discernment signal which shows the notice of release, and is transmitted to channel selection node 12 as a release notification message like 6th [ The ] figure 0. Specifically, CPU15 of Drawing 3 transmits via common line signal w110 from C3E18. In channel selection node 12, after performing release processing behind explained in full detail after CPU20 receives the above-mentioned signal via C3E22 of Drawing 4, the release completion message shown in 6th [ The ] figure ■ is returned to The originating switching node a via common line signal network 1o like 5th [ The ] figure @ from C3E22 of Drawing 4. The disconnect signal which the completion of release shown in 6th [ The ] figure ■ from Exchange no t'a to Subscriber 8 is made by this, then is worn via each relay switching node from The originating switching nodea, and is shown in 6th [ The ] figure @ to switching node d is transmitted one by one. Thereby, it wears and cutting is made like [ to arrival member 9 ] 6th [ The ] figure ■ in switching node d. If the completion of release which is worn, is worn from member 9 and shown in 6th [ The ] figure ■ to switching node d is made, the completion signal of release which is worn and is shown in Drawing 6 [phase] from switching node d to The originating switching nodea via each relay switching node will be transmitted one by one, and will end cut treating. Next, based on the operation flow chart of Drawing 7, and the lineblock diagram of each data of 8th [ The ] figure~figure 10, it explains about channel selection processing when channel selection node 12 receives the above-mentioned course inquiry message from The originating switching nodea via common line signal y410 of Drawing 2. Especially the operation flow chart of Drawing 7 is performed when CPU20 of Drawing 4 in channel selection node 12 operates the channel selection processing program which is not illustrated. The following explanation explains to an example communication-of-information network 7 which consists of switching node a, b, c, and d of Drawing 2. First, channel selection node 12 receives the identification number "shot PC=a" of request speed information r 6 Mb/s J, layer number r 045-201-9222 J, and The originating switching node a to the discernment signal and Both ° The originating switching node a indicates a course inquiry to be as a Path inquiry message (Drawing 7 31). thereby, Drawing 2 wears CPU20 of Drawing 4 from layer number DN, and member 9 is connected -- wearing -- a switching node number -- "-- it wears and calculates PCJ as follows (Drawing 7 32). First, layer number DN=045-201-9222 is set in input register 25 shown in Drawing 8 in CPU20 of Drawing 4. On the other hand, in DB24 of Drawing 4, it layer number (DN)/Wears and primary ~ the 6th six tables for switching node (PC) conversion are memorized. And the index even of the primary table~6th table is carried out in the order of ■-■-■-■-■-■ by making into index key information 26 top 6 figures except "0" begun among layer numbers DN set in input register 25. In the processing which is a number for long-distance number discernment at first "O", wears and calculates PC, it is unnecessary. Lower 3 figure "222" wears and is worn in a switching node, and since it is a member's line number, this [ its ] is also unnecessary. As concrete processing, first, the position of ■ on input register 25 wears, and it carries out the index of the address on primary table 27I corresponding to number r4J. Here it wears, the address of secondary table 27□ corresponding to a number "4" is stored in it, and secondary table 27□ corresponding by this is referred to. In secondary table 272, the position of ■ on input register 25 wears, and it carries out the index of the address on secondary table 2Tz corresponding to a number "5." Here it wears, the address of 3rd table 273 corresponding to a number "5" is stored in it, and 3rd table 273 corresponding by this is referred to. Hereinafter, refer even to 3rd table 273~5th table 27. for each Number of called party r2.rQJ "1" of ■~■ similarly. Here, it wears to each address of the last table [ 6th ], and the switching node number is memorized. therefore -- in 6th table 276 of Drawing 8, wear on input register 25, and the index of the address on 6th table 276 corresponding to a number "9" is carried out, and it wears by this -- a switching node number -- "-- it wears and, finally PC, can be found. In the example of Drawing 2, it wears and PC=d can be found. Next, the total switching node number for which The originating switching node a received CPU20 of Drawing 4 as a Path inquiry message "shot PC, From r suits of switching node number PC, it wears, wears from The originating switching node and searches for the channel information which was able to be found in processing of 7th [ The ] figure 82 and which is a candidate of the course to a switching node as follows (Drawing 7 33). In DB24 of Drawing 4, primary ~ the 3rd three tables shown in Drawing 9 are memorized as channel information data. And the index of the address on primary table 28. corresponding to the start to all the switching node number "shot PCs is carried out. Here the address of secondary table 282 corresponding to Exchange node number PC of r shots is stored, and secondary table 28□ corresponding by this is referred to. In secondary table 282, it wears and carries out the index of the address on secondary table 282 corresponding to a switching node number "suit PC." Here, it wears with all the switching node number "shot PCs, the address of 3rd table 283 corresponding to the combination of r suits of switching node number PC, is stored in it, and 3rd table 283 corresponding by this is referred to. wearing with Exchange node number PC of r shots on the last table [ 3rd ] here -- a switching node number -- "-- it wears and the candidate of the course corresponding to the combination of PCJ is remembered as channel information. thereby -- the -- wearing with all the switching node number "shot PC=a4 in the case of the example of 2 figure -- a switching node number -- "-- as it wears and is shown in Drawing 7 A as a candidate of the course corresponding to PC=dJ, ■a-d, ■a-b-d, and ■a-c-d can be found. Then, CPU20 of Drawing 4 calculates as follows the amount of present [ used ] of the circuit of each link between nodes of course candidate ■ who was able to be found in processing of figure 33 above-mentioned [ 7th ], ■, and ■, and adds the request speed information received as a course inquiry message from above-mentioned from switching node a (Drawing 7 34). Now, in DB24 of Drawing 4, two tables, the primary order [ 2nd ], shown in Drawing 10 (b) are memorized as amount data of present [ used ] of the link between nodes of some management data of the link between nodes. And the output side switching node number of the link to which its attention is paid first now "the index of the address on primary table 301 corresponding to appearance PCJ is carried out. The address of secondary table 302 corresponding to output side switching node number "appearance PCJ is stored here, and secondary table 302 corresponding by this is referred to. The operating capacity (total of line speed present in use) of the circuit corresponding to the link which becomes settled in the combination of an output side switching node number "appearance PC" and the input side switching node number "ON PC" is memorized by the secondary table. Therefore, the input side switching node number of the link to which its attention is paid now "the operating capacity of the circuit corresponding to the link to which its attention is paid can be found by carrying out the index of the address on secondary table 302 corresponding to ON PCJ. Among the course candidates who were able to be found in processing of above-mentioned Drawing 7 S3, about each of link a-b of link a -d1■a-b-d of course candidate ■a-d, b-d and link a-c of ■aqd, and c-d, it appears by the above-mentioned processing using the table of Drawings 10, and, specifically, calculates the amount used. As a result, as shown in 7th [ The ] figure , as for link a-d, 45 Mb/s and link a-b are 20 Mb/s and link b-d. a-c Both c -d can be found like 60 Mb/s. Request speed 6 Mb/s received as a course inquiry message from above-mentioned from switching node a is added to the amount of present [ used ] of each link which was able to be found as mentioned above. thereby, the addition result of each above-mentioned link a-d, a-b, b-d, a-c, and c-d serves as 66 Mb/s, 66 Mb/s, and 66 Mb/s each, 51 Mb/s, and b between 26-person s, as shown in 7th [ The ] figure . Next, CPU20 of Drawing 4 calculates as follows the maximum capacity of the circuit of each link between nodes of course candidate ■ who was able to be found in processing of above-mentioned 7th [ The ] figure 33, ■, and ■, and computes the usage rate (%) of each link as a percentage which broke each addition result that it was able to be found by each maximum capacity 7th [ The ] figure 84 [ above-mentioned ] (Drawing 7 35). Now, in DB24 of Drawing 4, two tables, the primary order [ 2nd ], shown in Drawing 10 (a) are memorized as maximum capacity data of the link between nodes of some management data of the link between nodes. And the output side switching node number of the link to which its attention is paid first now "the index of the address on primary table 29+ corresponding to appearance PCJ is carried out. The address of secondary table 292 corresponding to output side switching node number "appearance PCJ is stored here, and secondary table 29□ corresponding by this is referred to. The maximum capacity (maximum of an usable speed) of the circuit corresponding to the link which becomes settled in an output side switching node number "appearance PC" and the combination of input side switching node number "ON PCJ is memorized by the secondary table. Therefore, the maximum capacity of the circuit corresponding to the link to which its attention is paid can be found by Satoshi who does the index of the address on secondary table 29z corresponding to the input edge switching node number "ON PC" of the link to which its attention is paid now. Specifically, the maximum capacity is calculated by the above-mentioned processing using the table of Drawing 10 (a) about each of each of the same link a-d as above-mentioned Drawing 7 S4, a-b, b-d, a-c, and c-d. As a result, as shown in Drawing 7 C, link a-d is 50 Mb/s and link a-b, and both b-d is 100 Mb/s. Both link a-c and c-d can be found like 200 Mb/s. The usage rate (%) of each link is computed as a percentage which broke the addition result of each link which was able to be found in processing of above-mentioned 7th [ The ] figure 84 by the maximum capacity of each link which was able to be found as mentioned above. Thereby, the usage rate of each above-mentioned link a-dSa-b, b-dSa-c, and c-d will be 102%, 26%, 66%, 33%, and 33% respectively, as shown in Drawing 7 C. In each course candidate ■a-d, ■a-b-d, and ■a-c-d in which CPU20 of Drawing 4 was able to be found in processing of Drawing 7 S5 of the above after the above-mentioned processing, The usage rate of each link within each course makes the greatest thing the usage rate of the course, and chooses the smallest course candidate of a usage rate as the optimal path (Drawing 7 36). Specifically by course candidate ■a-d, 102% of the usage rate of link a-d turns into a usage rate of course candidate ■a-d like 7th [ The ] figure D■. In course candidate ■a-b-d, since the usage rate of link b-d is the maximum among link a-b and b-d, 66% of the usage rate turns into a usage rate of course candidate ■a-b-d like 7th [ The ] figure D■. In course candidate ■a-c-d, since the re-usage rate of link a-c and c-d is the same, 33% of the usage rate turns into a usage rate of course candidate ■a-c-d like 7th [ The ] figure D■. Therefore, course candidate ■a-c-d of the minimum [ usage rate ] is chosen as the optimal path like 7th [ The ] figure D■ among course candidate ■~■. the above-mentioned processing -- in addition -- adding request speed 6 Mb/s to each link a-c and c-d within selected course ■, as shown in Drawing 7 E -- the -- secondary table 302 ofO [ 1 ] figure (b) is updated (Drawing 7 37). CPU20 of Drawing 4 returns the course inquiry response message which added the channel information about selected optimal path a-c-d to The originating switching node a via common line signal network 10 after the above processing from C3E22 like already explained 5th [ The ] figure ■. Thus, channel selection processing for the optimal path selection in channel selection node 12 of Drawing 2 is realized. Finally, when Subscriber 8 of Drawing 2 makes a cutting demand like above-mentioned Drawing 5 or 6th [ The ] figure ■ explains the release processing by channel selection node 12 when the above-mentioned release notification message is transmitted from The originating switching nodea to channel selection node 12. As already explained, a release notification message adds the channel information received as a course inquiry response message at the time of identification number "shot PC=a J, request speed information r 6 Mb/s J, and Calling of The originating switching node a to the discernment signal which shows the notice of release (refer to the 6th figure 0). On the other hand, CPU20 (Drawing 4) of channel selection node 12 performs the operation flow chart of release processing of Drawing 11. First, a release notification message is received from The originating switching node (Drawing 7 39). Now, corresponding to the above-mentioned example of 7th [ The ] figure~figure 10, the channel information of the optimal path is course a-c-d of Drawing 2, and suppose that the request speed was 6 Mb/s. The originating switching node is a. Then, with reference to secondary table 302 of Drawing 10 in DB24 of Drawing 4 (b), request speed 6 Mb/s is subtracted and updated from the amount of present [ used ] to each link a-c within channel information, and c -d (Drawing 7 810). As already shown in Drawing 5 ■ or 6th [ The ] figure ■ after the above-mentioned processing, a release completion message is returned to The originating switching node a via common line signal network 10 from C3E22 of Drawing 4. Release processing in channel selection node 12 is realized by the above processing. As shown so far, channel selection node 12 of Drawing 2 is carrying out package management of the channel information of communication of information 1, and the Trahi knock of a Netting money object can be controlled by this example so that the block rate under communication becomes the minimum by this. By call setup processing when the optimal path is chosen, It wears from The originating switching nodea, channel information is transmitted one by one to switching node d, and it is in that case, Since channel information is lost when the channel information of one added to an address signal etc. decreases at a time, it wears and switching node d receives an address signal etc., whenever it progresses to the switching node of one beyond, efficient call setup processing can be performed. In channel selection processing of above-mentioned Drawing 7 in channel selection node 12, When choosing the smallest course of the usage rate of S6 as the optimal path and there are multiple courses of the minimum [ usage rate ], if the above-mentioned optimal path is determined based on the priority defined beforehand, rational channel selection can be performed. [Effect of the Invention] According to the present invention, a channel selection node carries out integrated management of the information about the channel selection between each switching node, It wears with The originating switching node that the block rate under communication becomes the minimum, and the optimal path between switching nodes is chosen, and in a communications network, since it wears with Subscriber based on the above-mentioned optimal path and a call setup can be performed among members, it becomes possible to attain equivalent-ization of traffic within the net. As call establishment procedures, a channel selection node returns channel information to The originating switching node, and it wears from all the switching nodes below first, and is to a switching node, It sets to each switching node, transmitting channel information and a call setup signal one by one, In order to transmit the call setup signal which distinguishes the switching node which should be connected to the next based on the received channel information, chooses the circuit to the node, and includes channel information to the following node, It wears and each circuit corresponding to the optimal path to a switching node is set up one by one, and as the overhead at the time of a call setup (delay) becomes the minimum, it becomes possible to wear with Subscriber and to perform the call setup between members.

[Brief Description of the Drawings]

Drawing 1 is a block diagram of the present invention, and Drawings 2 are a net lineblock diagram of this example, and Drawing 3, The lineblock diagram of a switching node and Drawing 4 are a lineblock diagram of channel selection lard (DB node), and Drawing 5, The explanatory view of call setup processing of operation and Drawing 6 are a timing chart of call setup processing of operation, and Drawing 7, The operation flow chart of channel selection processing, and Drawing 8, It wears and is a number (DN). It /Wears and, in the lineblock diagram of course (route) information data, and Drawing 10 (a) and (b), the lineblock diagram of node link management data and Drawing 11 of the lineblock diagram of switching node number (pc) conversion data and Drawing 9 are the operation flow charts of release processing. .. A communications network and ~21 --- Switching node .. Subscriber and .. wearing -- a member and .. a channel selection node, .. Course inquiry message. 16th table 276 Primary table 291 Primary table 30+ Between a "7between '-1 ''C High capacity 7-' node! "J7between '-5'; Usage data Drawing 10 of a lineblock diagram of An management data Drawing 11 of an operation flow chart of release processing