CA2001620C - Exchange route decision system and method - Google Patents
Exchange route decision system and methodInfo
- Publication number
- CA2001620C CA2001620C CA002001620A CA2001620A CA2001620C CA 2001620 C CA2001620 C CA 2001620C CA 002001620 A CA002001620 A CA 002001620A CA 2001620 A CA2001620 A CA 2001620A CA 2001620 C CA2001620 C CA 2001620C
- Authority
- CA
- Canada
- Prior art keywords
- exchange
- minimum cost
- line
- residual
- outgoing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q3/00—Selecting arrangements
- H04Q3/64—Distributing or queueing
- H04Q3/66—Traffic distributors
Abstract
An exchange route decision system and method which, when it is desired to realize tandem connection between outgoing and incoming communication terminal of various sorts and multiple rates requiring immediate data communication through a plurality of exchanges, take the residual capacities of relay lines between the outgoing and incoming terminals into consideration. In the system and method, the residual capacities of the relay lines between the outgoing and incoming terminals are divided into a plurality of classes based on predetermined line capacity units, data on routes providing minimum costs in association with the classes are controlled, and one of routes corresponding to the class satisfying the request line capacity of the outgoing terminal is selected to thereby realize the dandem connection between the outgoing and incoming terminals.
Description
200 1 ~20 The present invention relates generally to ~YrhAn~e route flec~ n systems and methods of ~ tion r ' ~ku wherein tandem connection is carried out between various sorts of and multiple speed ~ ~nation t~rmin~l~ through a 5 plurality of ~ J~ to realize immediate information ~ c~tion between the tc~ nAl~ and, more particularly, to an ~Y~-hJ-n~e route decision system and method which take residual line capacity into consideration.
Aspects of the prior art and present invention will be described by reference to the ;1( ~ ying drawings, in which:
Fig. 1 shows an example of an exchange system for explaining a prior art route decision method;
Fig. 2 shows the ~LU~ UL-: and contents of a minimum cost table used in the prior art route decision method;
Fig. 3 is a flowchart showing a prior art route decision procedure;
F1g. 4 shows an embodiment of an exchange system for 20 ~-Y~ 1n1n ~ a route decision method in accordance with the present invention;
Fig . 5 is a block diagram of an example of an ~Y~ h~n~e used in the present invention;
Fig. 6 shows the structure of a minimum cost table by 25 residual line capacity classes;
Fig. 7 shows organization criterions for the residual line capacity classes;
Fig. 8 shows a particular example of the organization criterions for the residual line capacity classes;
Fig. 9 is a flowchart showing a route decision procedure in accordance with the present invention Fig. 10 is a flowchart showing a procedure of preparing the minimum cost table by residual line capacity classes;
~ 200 ~ 620 Fig. 11 shows the contents of minimum cost vectors for input line residual capacity control;
Fig. 12 shows the DLLU~;LUL~ and contents of a minimum cost table by lines: and Fig. 13 shows the 27LLU~;LUL~ and contents of a minimum cost vector for output line residual capacity control.
Fig. 1 shows an example of a prior art c-~rhAn~e route decision method in the case where tandem cnnn-~c~ is 10 carried out between ~ ;c~tion t~mln5~ through a plurality of exchanges. In the drawing, tandem connection between an outgoing t~ min;~l lO and an ~r- in~ t~l~min 1l 11 is realized by selecting either one of tew routes , i . e ., exchange 12 ~line 20~Yrh~n~e 13~1ine 21-->exchange 14_>
line 22--;> r.YrhAn~e 15--~in~ in~ to~min;~l 11; exchange 12 line 20--> ~Yrh~n~e 13--~ line 23--~ exchange 16--,~ line 24--exchange 15 ~ n~ ~n~ t~rmin 1l 11.
The exchanges 12 to 16, which form a relay route for 20 transmission of communication data include connection type packet c~Yrh~n~ connection type line exchanges, - la -connection type asynchronous transfer mode exchanges and the like exchanges.
Prior to establishing the tandem connection between the outgoing and incoming terminals 10 and 11, the exchanges 12 to 16 ~l~t~rmi nf~C one of the routes which is minimum in the cost CJ of the routes in such a manner as to be mentioned in the following. Here, the cost CJ is expressed in terms of an estimated value of the route from the outgoing e~ d~ge 12 to the incoming exchange 15, and defined, for example, as the following equation.
CJ = ~ (17 + ~ DLI) (1) where Li represents the number of a line making up a route between the exchanges, DLI represents a distance between the ~ "~:s, ~ rl:~L~s~"l s the processing load cost of a relay exchange, and ,B represents a cost coefficient relating to line distance. The value (~ + ,B DL ~ ) indicates the load of the line and when the line is abnormal, the value is expressed in terms of ~.
Each of the exchanges 12, 13, 14 and 16 calculates the costs C~, of a plurality of routes from each of the exchanges to the incoming terminal 11. A minimum CN ~ of the costs CJ thus calculated as well as information on the number L~ of starting one of the lines contributing to the minimum cost CN I are held in a minimum cost table TBMC
with respect to the different exchanges, as shown in Fig.
Aspects of the prior art and present invention will be described by reference to the ;1( ~ ying drawings, in which:
Fig. 1 shows an example of an exchange system for explaining a prior art route decision method;
Fig. 2 shows the ~LU~ UL-: and contents of a minimum cost table used in the prior art route decision method;
Fig. 3 is a flowchart showing a prior art route decision procedure;
F1g. 4 shows an embodiment of an exchange system for 20 ~-Y~ 1n1n ~ a route decision method in accordance with the present invention;
Fig . 5 is a block diagram of an example of an ~Y~ h~n~e used in the present invention;
Fig. 6 shows the structure of a minimum cost table by 25 residual line capacity classes;
Fig. 7 shows organization criterions for the residual line capacity classes;
Fig. 8 shows a particular example of the organization criterions for the residual line capacity classes;
Fig. 9 is a flowchart showing a route decision procedure in accordance with the present invention Fig. 10 is a flowchart showing a procedure of preparing the minimum cost table by residual line capacity classes;
~ 200 ~ 620 Fig. 11 shows the contents of minimum cost vectors for input line residual capacity control;
Fig. 12 shows the DLLU~;LUL~ and contents of a minimum cost table by lines: and Fig. 13 shows the 27LLU~;LUL~ and contents of a minimum cost vector for output line residual capacity control.
Fig. 1 shows an example of a prior art c-~rhAn~e route decision method in the case where tandem cnnn-~c~ is 10 carried out between ~ ;c~tion t~mln5~ through a plurality of exchanges. In the drawing, tandem connection between an outgoing t~ min;~l lO and an ~r- in~ t~l~min 1l 11 is realized by selecting either one of tew routes , i . e ., exchange 12 ~line 20~Yrh~n~e 13~1ine 21-->exchange 14_>
line 22--;> r.YrhAn~e 15--~in~ in~ to~min;~l 11; exchange 12 line 20--> ~Yrh~n~e 13--~ line 23--~ exchange 16--,~ line 24--exchange 15 ~ n~ ~n~ t~rmin 1l 11.
The exchanges 12 to 16, which form a relay route for 20 transmission of communication data include connection type packet c~Yrh~n~ connection type line exchanges, - la -connection type asynchronous transfer mode exchanges and the like exchanges.
Prior to establishing the tandem connection between the outgoing and incoming terminals 10 and 11, the exchanges 12 to 16 ~l~t~rmi nf~C one of the routes which is minimum in the cost CJ of the routes in such a manner as to be mentioned in the following. Here, the cost CJ is expressed in terms of an estimated value of the route from the outgoing e~ d~ge 12 to the incoming exchange 15, and defined, for example, as the following equation.
CJ = ~ (17 + ~ DLI) (1) where Li represents the number of a line making up a route between the exchanges, DLI represents a distance between the ~ "~:s, ~ rl:~L~s~"l s the processing load cost of a relay exchange, and ,B represents a cost coefficient relating to line distance. The value (~ + ,B DL ~ ) indicates the load of the line and when the line is abnormal, the value is expressed in terms of ~.
Each of the exchanges 12, 13, 14 and 16 calculates the costs C~, of a plurality of routes from each of the exchanges to the incoming terminal 11. A minimum CN ~ of the costs CJ thus calculated as well as information on the number L~ of starting one of the lines contributing to the minimum cost CN I are held in a minimum cost table TBMC
with respect to the different exchanges, as shown in Fig.
2. For example, assume that, in the example of Fig. 1, the lines ZO, 21, 22, 23 and 24 have loads of 15, 15, 5, 25 and 10, respectively. Then the contents of the minimum cost tables TBMC for the respective exchanges 12 to 14 and 16 are as shown in Fig. 1. More specifically, when attention is directed to the exchange 13 which cuLL~:,,uu~lds to a branch point of the two routes from the outgoinq tPrminA1 10 to the incoming terminal 11, the exchange 13 selects the line 21 having the line number Lx of L2 as a minium cost line.
In the example of ~ig. 1, accordingly, the route of the exchange 12 ~ the exchange 13 ~ the exchange 14 ~ the exchange 15 is selected for the tandem connection between the outgoing and incoming tPrminA1~ 10 and 11.
Such a route decidinq procedure is shown in Fig. 3 in the form of a f lowchart . More in detail, when the outgoing terminal issues a calling request, the present system retrieves the minimum cost line number Lx relating to the incoming exchc.,.ge from the minimum cost table TBMC
(step 30). Thereafter, the system nPc whetehr or not the line capacity requested by the outgoing terminal remains in the line ~uLL~-a~uullding to the retrieved line number L,~ (step 31 ) . If not, then the system processes it as a call loss.
When the line capacity remains in the line corr~sron~l;ng to the retrieved line number Lx, the system detPrmi nPc that the line of the retrieved line number L~
is the minimum cost line (step 32~ and calls the adjacent exchange which is connected to the downstream end of the L,~ line in question (step 33).
Here, assuming in the above route deciding procedure ~ 200 ~ 620 that the outgoing terminal 10 requests a line capacity q of 2 and the lines 20 to 24 have residual capacities Q (which can be used by the lines 20 to 24) of 4, 5, l, 4 and 6, respectively, then the route extended from the exchange 12 to the exchange 14 can be used for tandem connection since the request capacity q of the outgoing terminal 10 is larger than any of the residual capacities Q of the lines 20 and 21. With respect to the route from the exchange 14 to the exchange 15, however, the residual capacity Q of the line 22 10 is smaller than the request capacity q and thus tandem connection is broken at the stage when the system calls the exchange 14, as shown by an arrow 25 in Fig. 1, whereby the system processes it as a call loss.
In this way, the prior art route decision method has had such a problem that, since the prior art selects one of the routes from the outgoing t~rmini31 to the int-nmin~
t~rmin~l on the basis of only the minimum cost information, there is a possibility that the prior art may select such a route as not satisfying the request line capacity of the 20 outgoing tPrmin~l, thus involving a call loss.
The present invention provides an exchange route decision system and method which can select one of routes which is minimum in cost without causing any call loss, whereby tandem connection can be realized between outgoing and i n~ nm; n~ t~rmi ni3 1 .q .
`' 20al620 .
In accordance with the present invention, the residual capacites of relay lines are divided into a plurality of classes based on predetermined capacity units, data on routes providing minimum costs are managed or controlled according to the classes, one of the routes corresponding to the class satisfying a request line capacity issued from an outgoing termianl is selected to realize tandem connection between outgoing and incoming terminals .
Each of exchanges divides the residual capacities ~ of lines into the plurality of classes based on, for example, several capacity units and controls data on the routes providinq the minimum costs according to the different classes. And if the exchange receives a new line connection request, then it selects one of the routes corr~crf-n~i; ng to the class satisfying the request line capacity ' ';ng in the line connection request.
Therefore, if there is one of the routes connecting the outgoing and incoming t~rmi n;~ which satisf ies the request line capacity of the outgoing terminal, then tandem connection can be attained between the outgoing and incoming terminals through this route. Thus, the system can avoid the generation of any call loss except for the case where any line satisfying the request line capacity of the outgoing t~rmi n;~l is not left in all the routes .
In this way, in accordance with the present invention, the routes providing the minimum costs are classified according to the residual line capacity and one ~-- 200 1 620 of the routes ~JLL~ ; nq to the class satisfying the request line capacity of the outgoing term~n~l 18 sequentially 8~1 ect~d. As a result, the system o~ the invention will not generate any call 1088 except for the 5 highly limited conditions and can reliably connect the outgoing and ~r ~ng t~rm~n;~ togethpr through the minimum cost route. Thus, when the invention system is used to decide one of routes of a network including ~Yrh:~n ~
cnnnPrtod to t~rmin~l~ which have various trJ~nF~n1F~inn r~tes 10 and handle voice data 1 n~n~ high immediateness, the invention system produces a remarkable effect.
.L .~
20~ 1 62(3 Referring to Fig. 4, there is shown an I ' 'i- of a route decision method in accordance with the present invention, in which a~; in the case of Fig. l, tandem connection is realized between outgoing and i n i n~
5 t~ n~l c 10 and ll by selecting either one of two routes, that is, PY~h~nge 12~1ine 20--~exchange 13--> line 21-->
exchange 14--~line 22--~ exchange 15~ in~ t~ nAl 11;
exchange 12--> line 20--; F.Yrh~n~e 13--~ line 23--~ exchange 16--line 24--,> ~Y~-h~n~e 15~ ;n~ t~rm~n;~l 11.
The ~Y~h~ng-~c 12 to 16, which form a relay route for tr~n~ cclon of ,_ lication data. include connection type packet ~Y~h~n~oc~ connection type line r-Y~h~nJ-~c, connection type aDyll-,llLvl~v~ls transfer mode ~yr.h:~n~c and -~6)01620 the like exchanges. The schematic arrangement of a connection type packet exchange as an example is shown by a block diagram in Fig. 5. In the drawing, a connection type packet exchange 100 includes terminal interfaces 101a to 101 c connected to terminal apparatuses 200a to 200c respectively, a line interface 102 connected to a line 300, a controller 103 for controlling the entire exchange 100, and a memory 104 for storing therein various control data in the controller 103. The terminal interfaces 101a to 101c, line interface 102 and memory 104 are connected to the controller 103 by a control bus 10~ and a data bus 106.
Each of the exchanges 12 to 16 in this ' or1~?~t of Fig. 4 has such a minimum cost table TBMCC as shown in Fig. 6, in which residual line capacities are divided into a plurality of classes according to predet~rm; ner capacity units and line numbers L,j CoLL~ ding to the minimum cost up to the incoming ~:x~l,ar.y~ ~exchange 15) with respect to the different classes are stored. The system decides one of the routes from the outgoing terminal 10 to the incoming tPrmin,i1 11 by referring to the table TBMCC.
With the aLL~l-y-~ L of Fig. 5, the minimum cost table TBMCC is provided in the memory 104. In Fig. 6, reference symbol Nj denotes the number of an incoming exchange, [C. J ~t~m] such as ICN.I ,C1~ or ~C"~"C2~ denotes the minimum cost of lines in the tandem connection directed to the incoming exchange N~, according to the residual line capacity class Cm, and L~m such as L~, or L~ 2 denotes a ;~00~6Z0 .
mini cost line number for the residual line capacity class C",.
As shown in Fig. 7, the residual line capacity classes C", are expressed in terms of such line capacity ranges as B, 5 Q < B2, B~ 5 Q < B3, B3 5 Q < B~,.., in which the line capacity Q is classified into ranges having a plurality of limits or stages ~uLL~ ullding to predeterminPd capacity units (such as Bl, B9,...). For example, class 1 corresponding to Cm = 1 indicates that tandem connection can be realized for the line request capacity q less than the capacity B,.
Assume now that the residual line capacity classes C", are divided as shown in Fig. 8, the lines 20 to 24 have loads, 15, 15, 5, 25 and 10 respectively as in the example of Fig. 1. Assume further that the request line capacity q of the outgoing tl~rmin;~l 10 is 2 and the lines 20 to 24 have residual capacities Q of 4 , 5 , 1, 4 and 6 respectively. With respect to the exchange 12, since the residual line capacity Q is "4", the residual line capacity is divided into classes 1 to 3 as shown by a minimum cost table TBMCC in Fig. 4. For class 1, the minimum cost is " 15 + 15 + 5 " and the minimum cost line number L", is L, ~oLL~,uullding to the line number of the line 20 in the minimum cost table. Similarly, for class 2, the minimum cost is "15 + 25 + 10" and the minimum cost line number L"2 is L~ corresponding to the line number of the line 20; for class 3, the minimum cost is "15 + 25 +
10 and the minimum cost line number L~3 is L, _g_ ` ` Z001620 corresponding to the line number of the line 20.
With respect to the exchange 13, the minimum cost is " 15 + 5" and the minimum cost line number L,l I is L2 corresponding to the line number of the line 21 for class 1; the minimum cost is " 25 + 10 " and the minimum cost line number L" 9 is L3 C~LLe~uUIlding to the line number of the line 23 for class 2; and the minimum cost is "25 + 10" and the minimum cost line number L,~3 i5 L3 CuLL~ullding to the line number of the line 23 f or class 3 With respect to th exchange 16, the minimum cost is " 10" and the minimum cost line number L,~ is L2 corresponding to the line number o~ the line 24, for all classes 1 to 3.
With respect to the exchange 14, since the residual line capacity Q is 1, the minimum cost is " 5 " and the minimum cost line number L~, is Ll coLL~ul.ding to the line 22 only for class 1.
Under such conditions, when the outgoing terminal 10 issues a calling request having a line request capacity q of 2, each of the ~ hAng~C 12 to 16 retrieves the associated minimum cost table TBMCC classified according to the residual line capacity classes and extract the minimum cost line numbers L~, for the class satisfying the line request capacity q (step 40), as shown by a route decision procedure flowchart in Fig. 9. Then, the system decides the extracted minimum cost line number L" as a minimum cost route leading to the incoming t~rmin~l 11 (step 41 ) and sends the calling request to the adjacent ~ ~ Z001620 exchange connected to the downstream end of the line of the decided minimum cost line number L~ (step 42). The adjacent exchange, when receiving the calling request, decides a minimum cost route leading to the incoming terminal 11 in the same manner as for the first e,Ychange.
More in detail, the exchange 12, since the line request capacity q is 2, selects the line number L, (line 20) for class 2 satisfying the condition q = 2. Next, the allg~ 13 selects the line number L3 (line 23) for class 2 satisfying the condition q = 2. The exchange 16 then slects the line number L2 (line 24) for class 2. As a result, the outgoing terminal 10 is connected with the incoming terminal 11 by the route of exchange 12 ~ line 20 ~ exchange 13 ~ line 23 -~ ~h~lla~ 16 1 line 24 ~ exchange 15.
As a result, any call loss will not take place excpept for the case where any route satisfying the request line capacity condition is not left at all.
In order to realize such route decision procedure as mentioned above, each of the exchanges must confirms the associated residual line capacity and prepare such a minimum cost table TM3CC classif ied according to the residual line capacity class as shown in Fig. 6.
Explanation will be made as to how to prepare the table TBMCC.
Shown in Fig . 10 is a f lowchart explaining a procedure of preparing the table TE3MCC. The table preparing procedure is e.Yecuted according to two .
conditions, i.e., whether or not the residual capacity or load of the each line has been changed or whether to be a constant period timing. More in detail, when one exchange first relays and sends a call from the outgoing terminal to another exchange provided at its downstream side, this causes the residual line capacity at the downstream exchange to be changed. If the line capacity change is to be shifted to another residual line capacity class, then the downstream ~ d..ge transmits to the input line (line number Ll ) to the upstream exchange such minimum cost values Cn ~ C~ classified according to the residual capacity classes of the lines leading to the incoming exchange N~ as shown in Fig. 11, as minimum cost vectors for input-line residual capacity control The upstream exchange, when receiving these vectors (step 50), updates to the then received minimum cost values CYJ,L~C~O the minimum cost values of input line number Ll in a by-lines minium cost table TBMCL (listing the minimum costs for all the lines leading to the incoming ~UIldll~e NJ according to the residual line capacity class, as shown in Fig. 12 (step 51 ) . Then the ~ lldllge compares the minimum cost values in the row direction in the table TBMCL, extracts the line number L,~ enabling the realization of minimum cost relay with respect to the incoming exchange NJ as well as the ~:--~t ullding minimum cost, and pLc:~dLes such a minimum cost table TBMCC classified according to the residual line capacity class as shown in Fig. 6 (step 52).
Thereafter, when the minimum cost table TBMCC
- 1~
` ~ 26~016Z0 classified according to the residual line capacity class is changed, the exchange adds the current load values of all the line numbers LR except for the input line number Ll to the minimum cost values of the line numbers Lh respectively, and prepares such a table TBMCLk for output line residual capacity minimum cost vector as shown in Fig. 13 (steps 53 and 54). When the contents of the table TBMCC have not been changed but data exchange timing is made at a regular period, the step 54 is executed. In the case of the regular-period data exchange timing, the exchange adds the current load values of all the line numbers including the input line number L, to the minimum cost values of the line numbers L~,.
Then, the ~x~hc,.lg~ transmits the contents of the table TBMCL" of Fig. 13 to the associated output line numbers L" (step 55). As a result, the system can discriminate the minimum cost values classified according to the residual line capacity class at the mutually adjacent eX~lldll~t~S, and can dynamically judge on the basis of the discimination and select one of routes up to the incoming t~rm; n~l providing the minimum cost while following load variations in the exchanges.
The residual line capacity class organization has been ef f ected on a two channel basis in the example of Fig. 8. This is for the purpose of avoiding such a disadvantage that, when class organization on a one channel basis is employed, each increase or decrease in the number of operating lines by one will cause the load fluctuations and correspondingly the frequent transfer of data telling the load f luctuations, which results in that the loads of the exchanges are increased or the line operating efficiency is reduced. In the case where the processing capacity of the each exchange is sufficiently large or connection lines have suf f icient capacities, the class organization may also be effected on a one channel basis as necessary.
In the example of ~ig. 1, accordingly, the route of the exchange 12 ~ the exchange 13 ~ the exchange 14 ~ the exchange 15 is selected for the tandem connection between the outgoing and incoming tPrminA1~ 10 and 11.
Such a route decidinq procedure is shown in Fig. 3 in the form of a f lowchart . More in detail, when the outgoing terminal issues a calling request, the present system retrieves the minimum cost line number Lx relating to the incoming exchc.,.ge from the minimum cost table TBMC
(step 30). Thereafter, the system nPc whetehr or not the line capacity requested by the outgoing terminal remains in the line ~uLL~-a~uullding to the retrieved line number L,~ (step 31 ) . If not, then the system processes it as a call loss.
When the line capacity remains in the line corr~sron~l;ng to the retrieved line number Lx, the system detPrmi nPc that the line of the retrieved line number L~
is the minimum cost line (step 32~ and calls the adjacent exchange which is connected to the downstream end of the L,~ line in question (step 33).
Here, assuming in the above route deciding procedure ~ 200 ~ 620 that the outgoing terminal 10 requests a line capacity q of 2 and the lines 20 to 24 have residual capacities Q (which can be used by the lines 20 to 24) of 4, 5, l, 4 and 6, respectively, then the route extended from the exchange 12 to the exchange 14 can be used for tandem connection since the request capacity q of the outgoing terminal 10 is larger than any of the residual capacities Q of the lines 20 and 21. With respect to the route from the exchange 14 to the exchange 15, however, the residual capacity Q of the line 22 10 is smaller than the request capacity q and thus tandem connection is broken at the stage when the system calls the exchange 14, as shown by an arrow 25 in Fig. 1, whereby the system processes it as a call loss.
In this way, the prior art route decision method has had such a problem that, since the prior art selects one of the routes from the outgoing t~rmini31 to the int-nmin~
t~rmin~l on the basis of only the minimum cost information, there is a possibility that the prior art may select such a route as not satisfying the request line capacity of the 20 outgoing tPrmin~l, thus involving a call loss.
The present invention provides an exchange route decision system and method which can select one of routes which is minimum in cost without causing any call loss, whereby tandem connection can be realized between outgoing and i n~ nm; n~ t~rmi ni3 1 .q .
`' 20al620 .
In accordance with the present invention, the residual capacites of relay lines are divided into a plurality of classes based on predetermined capacity units, data on routes providing minimum costs are managed or controlled according to the classes, one of the routes corresponding to the class satisfying a request line capacity issued from an outgoing termianl is selected to realize tandem connection between outgoing and incoming terminals .
Each of exchanges divides the residual capacities ~ of lines into the plurality of classes based on, for example, several capacity units and controls data on the routes providinq the minimum costs according to the different classes. And if the exchange receives a new line connection request, then it selects one of the routes corr~crf-n~i; ng to the class satisfying the request line capacity ' ';ng in the line connection request.
Therefore, if there is one of the routes connecting the outgoing and incoming t~rmi n;~ which satisf ies the request line capacity of the outgoing terminal, then tandem connection can be attained between the outgoing and incoming terminals through this route. Thus, the system can avoid the generation of any call loss except for the case where any line satisfying the request line capacity of the outgoing t~rmi n;~l is not left in all the routes .
In this way, in accordance with the present invention, the routes providing the minimum costs are classified according to the residual line capacity and one ~-- 200 1 620 of the routes ~JLL~ ; nq to the class satisfying the request line capacity of the outgoing term~n~l 18 sequentially 8~1 ect~d. As a result, the system o~ the invention will not generate any call 1088 except for the 5 highly limited conditions and can reliably connect the outgoing and ~r ~ng t~rm~n;~ togethpr through the minimum cost route. Thus, when the invention system is used to decide one of routes of a network including ~Yrh:~n ~
cnnnPrtod to t~rmin~l~ which have various trJ~nF~n1F~inn r~tes 10 and handle voice data 1 n~n~ high immediateness, the invention system produces a remarkable effect.
.L .~
20~ 1 62(3 Referring to Fig. 4, there is shown an I ' 'i- of a route decision method in accordance with the present invention, in which a~; in the case of Fig. l, tandem connection is realized between outgoing and i n i n~
5 t~ n~l c 10 and ll by selecting either one of two routes, that is, PY~h~nge 12~1ine 20--~exchange 13--> line 21-->
exchange 14--~line 22--~ exchange 15~ in~ t~ nAl 11;
exchange 12--> line 20--; F.Yrh~n~e 13--~ line 23--~ exchange 16--line 24--,> ~Y~-h~n~e 15~ ;n~ t~rm~n;~l 11.
The ~Y~h~ng-~c 12 to 16, which form a relay route for tr~n~ cclon of ,_ lication data. include connection type packet ~Y~h~n~oc~ connection type line r-Y~h~nJ-~c, connection type aDyll-,llLvl~v~ls transfer mode ~yr.h:~n~c and -~6)01620 the like exchanges. The schematic arrangement of a connection type packet exchange as an example is shown by a block diagram in Fig. 5. In the drawing, a connection type packet exchange 100 includes terminal interfaces 101a to 101 c connected to terminal apparatuses 200a to 200c respectively, a line interface 102 connected to a line 300, a controller 103 for controlling the entire exchange 100, and a memory 104 for storing therein various control data in the controller 103. The terminal interfaces 101a to 101c, line interface 102 and memory 104 are connected to the controller 103 by a control bus 10~ and a data bus 106.
Each of the exchanges 12 to 16 in this ' or1~?~t of Fig. 4 has such a minimum cost table TBMCC as shown in Fig. 6, in which residual line capacities are divided into a plurality of classes according to predet~rm; ner capacity units and line numbers L,j CoLL~ ding to the minimum cost up to the incoming ~:x~l,ar.y~ ~exchange 15) with respect to the different classes are stored. The system decides one of the routes from the outgoing terminal 10 to the incoming tPrmin,i1 11 by referring to the table TBMCC.
With the aLL~l-y-~ L of Fig. 5, the minimum cost table TBMCC is provided in the memory 104. In Fig. 6, reference symbol Nj denotes the number of an incoming exchange, [C. J ~t~m] such as ICN.I ,C1~ or ~C"~"C2~ denotes the minimum cost of lines in the tandem connection directed to the incoming exchange N~, according to the residual line capacity class Cm, and L~m such as L~, or L~ 2 denotes a ;~00~6Z0 .
mini cost line number for the residual line capacity class C",.
As shown in Fig. 7, the residual line capacity classes C", are expressed in terms of such line capacity ranges as B, 5 Q < B2, B~ 5 Q < B3, B3 5 Q < B~,.., in which the line capacity Q is classified into ranges having a plurality of limits or stages ~uLL~ ullding to predeterminPd capacity units (such as Bl, B9,...). For example, class 1 corresponding to Cm = 1 indicates that tandem connection can be realized for the line request capacity q less than the capacity B,.
Assume now that the residual line capacity classes C", are divided as shown in Fig. 8, the lines 20 to 24 have loads, 15, 15, 5, 25 and 10 respectively as in the example of Fig. 1. Assume further that the request line capacity q of the outgoing tl~rmin;~l 10 is 2 and the lines 20 to 24 have residual capacities Q of 4 , 5 , 1, 4 and 6 respectively. With respect to the exchange 12, since the residual line capacity Q is "4", the residual line capacity is divided into classes 1 to 3 as shown by a minimum cost table TBMCC in Fig. 4. For class 1, the minimum cost is " 15 + 15 + 5 " and the minimum cost line number L", is L, ~oLL~,uullding to the line number of the line 20 in the minimum cost table. Similarly, for class 2, the minimum cost is "15 + 25 + 10" and the minimum cost line number L"2 is L~ corresponding to the line number of the line 20; for class 3, the minimum cost is "15 + 25 +
10 and the minimum cost line number L~3 is L, _g_ ` ` Z001620 corresponding to the line number of the line 20.
With respect to the exchange 13, the minimum cost is " 15 + 5" and the minimum cost line number L,l I is L2 corresponding to the line number of the line 21 for class 1; the minimum cost is " 25 + 10 " and the minimum cost line number L" 9 is L3 C~LLe~uUIlding to the line number of the line 23 for class 2; and the minimum cost is "25 + 10" and the minimum cost line number L,~3 i5 L3 CuLL~ullding to the line number of the line 23 f or class 3 With respect to th exchange 16, the minimum cost is " 10" and the minimum cost line number L,~ is L2 corresponding to the line number o~ the line 24, for all classes 1 to 3.
With respect to the exchange 14, since the residual line capacity Q is 1, the minimum cost is " 5 " and the minimum cost line number L~, is Ll coLL~ul.ding to the line 22 only for class 1.
Under such conditions, when the outgoing terminal 10 issues a calling request having a line request capacity q of 2, each of the ~ hAng~C 12 to 16 retrieves the associated minimum cost table TBMCC classified according to the residual line capacity classes and extract the minimum cost line numbers L~, for the class satisfying the line request capacity q (step 40), as shown by a route decision procedure flowchart in Fig. 9. Then, the system decides the extracted minimum cost line number L" as a minimum cost route leading to the incoming t~rmin~l 11 (step 41 ) and sends the calling request to the adjacent ~ ~ Z001620 exchange connected to the downstream end of the line of the decided minimum cost line number L~ (step 42). The adjacent exchange, when receiving the calling request, decides a minimum cost route leading to the incoming terminal 11 in the same manner as for the first e,Ychange.
More in detail, the exchange 12, since the line request capacity q is 2, selects the line number L, (line 20) for class 2 satisfying the condition q = 2. Next, the allg~ 13 selects the line number L3 (line 23) for class 2 satisfying the condition q = 2. The exchange 16 then slects the line number L2 (line 24) for class 2. As a result, the outgoing terminal 10 is connected with the incoming terminal 11 by the route of exchange 12 ~ line 20 ~ exchange 13 ~ line 23 -~ ~h~lla~ 16 1 line 24 ~ exchange 15.
As a result, any call loss will not take place excpept for the case where any route satisfying the request line capacity condition is not left at all.
In order to realize such route decision procedure as mentioned above, each of the exchanges must confirms the associated residual line capacity and prepare such a minimum cost table TM3CC classif ied according to the residual line capacity class as shown in Fig. 6.
Explanation will be made as to how to prepare the table TBMCC.
Shown in Fig . 10 is a f lowchart explaining a procedure of preparing the table TE3MCC. The table preparing procedure is e.Yecuted according to two .
conditions, i.e., whether or not the residual capacity or load of the each line has been changed or whether to be a constant period timing. More in detail, when one exchange first relays and sends a call from the outgoing terminal to another exchange provided at its downstream side, this causes the residual line capacity at the downstream exchange to be changed. If the line capacity change is to be shifted to another residual line capacity class, then the downstream ~ d..ge transmits to the input line (line number Ll ) to the upstream exchange such minimum cost values Cn ~ C~ classified according to the residual capacity classes of the lines leading to the incoming exchange N~ as shown in Fig. 11, as minimum cost vectors for input-line residual capacity control The upstream exchange, when receiving these vectors (step 50), updates to the then received minimum cost values CYJ,L~C~O the minimum cost values of input line number Ll in a by-lines minium cost table TBMCL (listing the minimum costs for all the lines leading to the incoming ~UIldll~e NJ according to the residual line capacity class, as shown in Fig. 12 (step 51 ) . Then the ~ lldllge compares the minimum cost values in the row direction in the table TBMCL, extracts the line number L,~ enabling the realization of minimum cost relay with respect to the incoming exchange NJ as well as the ~:--~t ullding minimum cost, and pLc:~dLes such a minimum cost table TBMCC classified according to the residual line capacity class as shown in Fig. 6 (step 52).
Thereafter, when the minimum cost table TBMCC
- 1~
` ~ 26~016Z0 classified according to the residual line capacity class is changed, the exchange adds the current load values of all the line numbers LR except for the input line number Ll to the minimum cost values of the line numbers Lh respectively, and prepares such a table TBMCLk for output line residual capacity minimum cost vector as shown in Fig. 13 (steps 53 and 54). When the contents of the table TBMCC have not been changed but data exchange timing is made at a regular period, the step 54 is executed. In the case of the regular-period data exchange timing, the exchange adds the current load values of all the line numbers including the input line number L, to the minimum cost values of the line numbers L~,.
Then, the ~x~hc,.lg~ transmits the contents of the table TBMCL" of Fig. 13 to the associated output line numbers L" (step 55). As a result, the system can discriminate the minimum cost values classified according to the residual line capacity class at the mutually adjacent eX~lldll~t~S, and can dynamically judge on the basis of the discimination and select one of routes up to the incoming t~rm; n~l providing the minimum cost while following load variations in the exchanges.
The residual line capacity class organization has been ef f ected on a two channel basis in the example of Fig. 8. This is for the purpose of avoiding such a disadvantage that, when class organization on a one channel basis is employed, each increase or decrease in the number of operating lines by one will cause the load fluctuations and correspondingly the frequent transfer of data telling the load f luctuations, which results in that the loads of the exchanges are increased or the line operating efficiency is reduced. In the case where the processing capacity of the each exchange is sufficiently large or connection lines have suf f icient capacities, the class organization may also be effected on a one channel basis as necessary.
Claims (16)
1. An exchange route decision system for use in a network, said network comprising a plurality of terminals and exchanges, said plurality of terminals using a plurality of transmission rates, transmitting real-time data, and including an outgoing terminal and an incoming terminal, said plurality of exchanges connected by lines having varying capacities and varying loads to establish a plurality of communication routes and including an outgoing exchange connected to said outgoing terminal and an incoming exchange connected to said incoming exchange, and said exchange route decision system for determining one of said plurality of communication routes between said outgoing exchange and said incoming exchange, comprising:
memory means for dividing residual capacities of said lines into a plurality of residual line capacity classes and for storing minimum cost values corresponding to a plurality of minimum cost routes from said outgoing exchange to said incoming exchange, said plurality of minimum cost routes determined in accordance with said plurality of residual line capacity classes;
retrieval means for retrieving a minimum cost value in accordance with one of said plurality of residual line capacity classes in response to a line capacity requested by said outgoing terminal; and decision means for selecting one of said plurality of communication routes in accordance with said retrieved minimum cost value.
memory means for dividing residual capacities of said lines into a plurality of residual line capacity classes and for storing minimum cost values corresponding to a plurality of minimum cost routes from said outgoing exchange to said incoming exchange, said plurality of minimum cost routes determined in accordance with said plurality of residual line capacity classes;
retrieval means for retrieving a minimum cost value in accordance with one of said plurality of residual line capacity classes in response to a line capacity requested by said outgoing terminal; and decision means for selecting one of said plurality of communication routes in accordance with said retrieved minimum cost value.
2. An exchange route decision system as set forth in claim 1, wherein said lines are designated by respective line numbers and said memory means stores the line numbers corresponding to the lines comprising said plurality of minimum cost routes.
3. An exchange route decision system as set forth in claim 1, wherein said retrieval means are responsive to a line capacity request by said incoming exchange.
4. An exchange route decision system as set forth in claim 1, wherein each minimum cost value is an estimate expressed in terms of a sum of the line loads for the lines comprising each corresponding minimum cost route.
5. An exchange route decision system as set forth in claim 1, wherein each minimum cost value is an estimate defined by an equation;
Cj = ? (.alpha. + .beta. DLi), wherein Li denote lines comprising each corresponding minimum cost route, DLi denote distances between said lines, .alpha.
denotes a processing load cost for a respective exchange and .beta. denotes a cost coefficient related to line distance.
Cj = ? (.alpha. + .beta. DLi), wherein Li denote lines comprising each corresponding minimum cost route, DLi denote distances between said lines, .alpha.
denotes a processing load cost for a respective exchange and .beta. denotes a cost coefficient related to line distance.
6. An exchange route decision system for use in a network, said network comprising a plurality of terminals and exchanges, said plurality of terminals using a plurality of transmission rates, transmitting real-time data, and including an outgoing terminal and an incoming terminal, said plurality of exchanges connected by lines having varying capacities and varying loads to establish a plurality of communication routes and including an outgoing exchange connected to said outgoing terminal and an incoming exchange connected to said incoming exchange, and said exchange route decision system for determining one of said plurality of communication routes between said outgoing exchange and said incoming exchange, comprising:
memory means for dividing residual capacities of said lines into a plurality of residual line capacity classes and for storing minimum cost values corresponding to a plurality of minimum cost routes from said outgoing exchange to said incoming exchange, said plurality of minimum cost routes determined in accordance with said plurality of residual line capacity classes;
retrieval means for retrieving a minimum cost value corresponding to one of said plurality of residual line capacity classes in response to a line capacity requested by said outgoing terminal;
decision means for selecting one of said plurality of communication routes in accordance with the retrieved minimum cost value; and communication means between adjacent exchanges for transmitting and receiving residual-line-capacity control minimum cost vectors.
memory means for dividing residual capacities of said lines into a plurality of residual line capacity classes and for storing minimum cost values corresponding to a plurality of minimum cost routes from said outgoing exchange to said incoming exchange, said plurality of minimum cost routes determined in accordance with said plurality of residual line capacity classes;
retrieval means for retrieving a minimum cost value corresponding to one of said plurality of residual line capacity classes in response to a line capacity requested by said outgoing terminal;
decision means for selecting one of said plurality of communication routes in accordance with the retrieved minimum cost value; and communication means between adjacent exchanges for transmitting and receiving residual-line-capacity control minimum cost vectors.
7. An exchange route decision system as set forth in claim 6, wherein said communication means transmits and receives said residual-line-capacity control minimum cost vectors when said residual line capacity classes or said minimum cost values are changed.
8. An exchange route decision system as set forth in claim 6, wherein said communication means cyclically transmits said residual-line-capacity control minimum cost vectors at a predetermined period.
9. An exchange route decision system as set forth in claim 6, said communication means further comprising:
vector generating means for generating residual-line-capacity control minimum cost vectors to be transmitted to an adjacent exchange in response to residual-line-capacity control minimum cost vectors received from another adjacent exchange.
vector generating means for generating residual-line-capacity control minimum cost vectors to be transmitted to an adjacent exchange in response to residual-line-capacity control minimum cost vectors received from another adjacent exchange.
10. An exchange route decision system as set forth in claim 9, said vector generating means further comprising:
means for preparing a minimum cost table containing minimum cost values for lines comprising said plurality of communication routes, said minimum cost values being determined in accordance with said incoming exchange and said residual line capacity classes;
means for rewriting in said minimum cost table in response to received residual-line-capacity control minimum cost vectors; and, means for retrieving the minimum cost values contained in said minimum cost table and for adding line loads for the lines comprising each of said plurality of communication routes up to an adjacent exchange to said retrieved minimum cost line values, thereby generating said residual-line-capacity control minimum cost vectors.
means for preparing a minimum cost table containing minimum cost values for lines comprising said plurality of communication routes, said minimum cost values being determined in accordance with said incoming exchange and said residual line capacity classes;
means for rewriting in said minimum cost table in response to received residual-line-capacity control minimum cost vectors; and, means for retrieving the minimum cost values contained in said minimum cost table and for adding line loads for the lines comprising each of said plurality of communication routes up to an adjacent exchange to said retrieved minimum cost line values, thereby generating said residual-line-capacity control minimum cost vectors.
11. A route decision method in which tandem connection between an outgoing terminal and an incoming terminal is attained through a network, comprising a plurality of exchanges connected by lines having varying capacities and varying loads to form a plurality of communication routes, by selecting at each one of said plurality of exchanges, a minimum cost route from said plurality of communication routes between said outgoing terminal and said incoming terminal, comprising the steps at each exchange of:
dividing line capacity not currently being used into a plurality of line capacity classes based on predetermined capacity units for each one of the lines comprising said plurality of communication routes;
determining minimum cost values for corresponding to a plurality of minimum cost routes said plurality of minimum cost routes determines in accordance with said plurality of line capacity classes;
selecting one of said plurality of communication routes based on said minimum cost values in response to one of said plurality of line capacity classes requested by said outgoing terminal; and performing tandem connection between said outgoing terminal and said incoming terminal through said selected communication route.
dividing line capacity not currently being used into a plurality of line capacity classes based on predetermined capacity units for each one of the lines comprising said plurality of communication routes;
determining minimum cost values for corresponding to a plurality of minimum cost routes said plurality of minimum cost routes determines in accordance with said plurality of line capacity classes;
selecting one of said plurality of communication routes based on said minimum cost values in response to one of said plurality of line capacity classes requested by said outgoing terminal; and performing tandem connection between said outgoing terminal and said incoming terminal through said selected communication route.
12. An exchange route decision method as set forth in claim 11, wherein each minimum cost value is an estimate expressed in terms of a sum of line loads for the lines comprising each corresponding minimum cost.
13. An exchange route decision method as set forth in claim 11, wherein each minimum cost value is an estimate defined as an equation Cj = ? (.alpha. + .beta. DLi), where Li denote lines of each route, DLi denote distances between said lines, .alpha. denotes a processing load cost of a relay exchange and .beta. denotes a cost coefficient relation to line distance.
14. An exchange route decision method as set forth in claim 11, further comprising the step of modifying said minimum cost values and sequentially transmitting said minimum cost values to an adjacent exchange when one of said plurality of residual line capacity classes is changed.
15. An exchange route decision method as set forth in claim 11, further comprising the step of modifying said minimum values and sequentially transmitting said minimum cost values to an adjacent exchange when a line load is changed.
16. An exchange route decision method as set forth in claim 11, further comprising the step of cyclically modifying said minimum cost values and sequentially transmitting said minimum cost values to an adjacent exchange at a predetermined period.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP271603/1988 | 1988-10-27 | ||
| JP63271603A JPH02117236A (en) | 1988-10-27 | 1988-10-27 | Route deciding system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2001620A1 CA2001620A1 (en) | 1990-04-27 |
| CA2001620C true CA2001620C (en) | 1996-10-01 |
Family
ID=17502377
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002001620A Expired - Fee Related CA2001620C (en) | 1988-10-27 | 1989-10-26 | Exchange route decision system and method |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US5038340A (en) |
| JP (1) | JPH02117236A (en) |
| CA (1) | CA2001620C (en) |
Families Citing this family (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02142259A (en) * | 1988-11-24 | 1990-05-31 | Toshiba Corp | Route determining system |
| JP2834293B2 (en) * | 1990-08-17 | 1998-12-09 | 株式会社日立製作所 | How to change the virtual path capacity |
| US5243592A (en) * | 1990-10-15 | 1993-09-07 | Digital Equipment Corporation | Method and apparatus for distance vector routing on datagram point-to-point links |
| US5850385A (en) * | 1991-09-24 | 1998-12-15 | Kabushiki Kaisha Toshiba | Cell loss rate sensitive routing and call admission control method |
| US5400333A (en) * | 1992-04-07 | 1995-03-21 | Digital Equipment Corporation | Detecting LAN number misconfiguration |
| US5398242A (en) * | 1992-04-07 | 1995-03-14 | Digital Equipment Corporation | Automatically configuring LAN numbers |
| US5327424A (en) * | 1992-04-07 | 1994-07-05 | Digital Equipment Corporation | Automatically configuring parallel bridge numbers |
| US5323394A (en) * | 1992-04-07 | 1994-06-21 | Digital Equipment Corporation | Selecting optimal routes in source routing bridging without exponential flooding of explorer packets |
| US5844902A (en) * | 1992-04-07 | 1998-12-01 | Cabletron Systems, Inc. | Assigning multiple parallel bridge numbers to bridges |
| US5381404A (en) * | 1992-07-14 | 1995-01-10 | Mita Industrial Co., Ltd. | Packet-switching communication network and method of design |
| US5446730A (en) * | 1993-09-20 | 1995-08-29 | Motorola, Inc. | Method for dynamic connection management in integrated communication networks |
| JP3170133B2 (en) * | 1994-02-25 | 2001-05-28 | 富士通株式会社 | Switching line selection method and switching line selection device |
| US5754787A (en) * | 1994-12-23 | 1998-05-19 | Intel Corporation | System for electronically publishing objects with header specifying minimum and maximum required transport delivery rates and threshold being amount publisher is willing to pay |
| US6567410B1 (en) | 1996-08-08 | 2003-05-20 | Enterasys Networks, Inc. | Assigning multiple parallel bridge numbers to bridges having three or more ports |
| JPH1168750A (en) * | 1997-08-22 | 1999-03-09 | Nec Corp | Network management system |
| GB2339108A (en) | 1998-07-01 | 2000-01-12 | Ericsson Telefon Ab L M | Call routing data management |
| JP3995145B2 (en) * | 2002-01-22 | 2007-10-24 | テレフオンアクチーボラゲット エル エム エリクソン（パブル） | Communication control device and communication control method |
| US20070002740A1 (en) * | 2005-06-30 | 2007-01-04 | Scott Evans | Biasing of network node prioritization to improve per-hop behavior based on performance necessary for a packet to meet end-to-end QoS goals |
| US8040808B1 (en) * | 2008-10-20 | 2011-10-18 | Juniper Networks, Inc. | Service aware path selection with a network acceleration device |
| WO2024069843A1 (en) * | 2022-09-29 | 2024-04-04 | 楽天モバイル株式会社 | Distributed deployment control for microservices |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0234191B1 (en) * | 1986-01-09 | 1993-12-29 | Nec Corporation | Packet-switched communications network with parallel virtual circuits for re-routing message packets |
| JPH02220531A (en) * | 1989-02-22 | 1990-09-03 | Toshiba Corp | Call connection control system and flow monitor system |
-
1988
- 1988-10-27 JP JP63271603A patent/JPH02117236A/en active Pending
-
1989
- 1989-10-25 US US07/426,380 patent/US5038340A/en not_active Expired - Fee Related
- 1989-10-26 CA CA002001620A patent/CA2001620C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02117236A (en) | 1990-05-01 |
| CA2001620A1 (en) | 1990-04-27 |
| US5038340A (en) | 1991-08-06 |
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