JP3406777B2 - Exchange system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ATM (As
The present invention relates to a communication mode switching system that divides data into cells, assigns each cell to one of a plurality of virtual channels of a transmission path, and transfers the cells, such as an asynchronous transfer mode. 2. Description of the Related Art As a communication system used in an ATM network, there is an SVC (Switched Virtual Connection: partner selection connection) in which a communication is specified each time a communication starts and a connection is specified. In other words, this SVC is set to VC
(Virtual Channel: virtual channel) is a communication method for establishing connection with a partner. On the other hand, such an SVC
, The connection partner is set in advance by PVC (Perm
There is a communication method called anent Virtual Connection. This PVC is a communication method in which an unused (empty) VC is checked before communication with a partner is started, and the connection with the partner is fixed by the obtained VC. [0003] However, when setting up a connection by the above-described communication method, there are the following problems. When setting a PVC connection,
By SVC, VPI (Virtual Path Identifier) and VCI (Virtual Channel Identifier)
r: virtual channel identifier)), since the usage status changes at any time, the operator investigates unused VPIs and VCIs,
The VPI and VCI may be used in SVC. Therefore, when the operator uses the V
If an attempt is made to set a connection by specifying a PI and a VCI, the connection cannot be set. In an ATM network, CBR (Cons
tant Bit Rate: fixed rate service and VBR (Variab)
le Bit Rate: QoS (Quality of Service) that regulates services related to transmission rate, such as variable rate service.
ce: service quality class). However, such a plurality of connections are
When setting on a line having a PI, since the VPI is used in the order of connection setting request, a specific Qo
A state occurs where only S occupies the band,
There was a problem that it hindered efficient use. For example, if a request for setting a CBR connection used for voice is continuously generated, there is a possibility that another QoS connection cannot be set. On a line having a plurality of VPIs,
Set a plurality of QoS connections, and
When PI is shared by multiple QoS connections,
Since VPIs are used in the order of connection setting requests, a specific QoS is used preferentially (for example, a certain VPI gives priority to a CBR connection used for voice,
ABR (Avairable Bit Rate: available rate service) connection used for data cannot be used when CBR is available. [0007] From the above point, even if the SVC communication and the capture of the VPI and VCI compete against the above-mentioned problem,
It has been desired to realize a system that can capture the VPI and VCI for PVC by one PVC setting request and improve the convenience for the operator. In addition, with respect to the above and the above problems, it has been desired to realize a switching system capable of efficiently using a band according to a purpose of using a network. The present invention employs the following structure to solve the above-mentioned problems. According to the present invention, in a communication mode switching system in which data is divided into cells, each cell is assigned to any one of a plurality of virtual channels of a transmission path and transferred, communication with an arbitrary party is started. each sends a capture request for the virtual channel to be used, based on the response to this, the temporary to any other party
An SVC control unit that performs a connection selection for setting a virtual channel, sends a request for capturing a virtual channel to be used to an arbitrary communication partner before starting communication, and, based on a response to the request, captures an arbitrary virtual channel. A PVC control unit for performing fixed connection of a partner for fixedly setting a virtual channel to a partner, and a plurality of virtual channels
Channel vacancy table and duplicates are arranged in a predetermined order.
Transfer rate services for a number of virtual channels
Priority usage indicating the priority of the specified service class
Having a possible QoS table, an SVC controller and a PVC controller
If there is a request for use in any service class from
Search the available QoS table with priority and request the service
Search for virtual channels in descending order of priority by class and extract
Check the vacancy of the issued virtual channel in the channel vacancy table,
A channel management unit that responds to the requesting control unit when the channel is an empty virtual channel .
You. <Description of Configuration > The communication mode to which the present invention is applied is, for example, ATM. However, other than this, data is divided into cells, and each cell is divided into a plurality of virtual channels on a transmission line. If the communication mode is one that has a partner selection connection function that captures the channel to be used each time communication starts and a partner fixed connection function that determines the channel to use before communication starts, , Are equally applicable. [0010] Each time the communication is started, the SVC control unit sends a channel capture request to the channel management unit. When a channel number is designated to the channel management unit based on a channel capture request from the operator, the PVC control unit determines whether the channel is empty or omits the channel number. If there is, a search request for a free channel is sent . The channel vacancy table of the channel management unit is, for example, a table in which the row direction corresponds to the VPI number and the column direction corresponds to the VCI number. even if the good. Chi Yaneru management unit, when there is a channel acquisition request, the search for the channels empty塞表, from young number in the case of SVC controller, in the case of PVC control unit performs the old turn, searches portions do not overlap As described above, if the search is performed from a different direction, the search may be performed, for example, from the middle of the array to the front and back. With such a configuration, even if there is a channel capture request from the SVC control unit and the PVC control unit, it is possible to extract an empty channel in a short time. The service class in the priority-enabled QoS table is, for example, C in the ATM switching system.
Although the service class is a service class such as BR / VBRrt / VBRnrt / UBR / ABR, other services can be similarly targeted as long as they specify a service related to a transfer rate. [0016] [0017] [0018] [0019] Then, the QoS table is obtained by applying a priority of the service class for each channel. By this means, when there is a request for use in an arbitrary service class from the SVC control unit and the PVC control unit, the channel management unit determines in the priority-enabled QoS table in the order of the highest priority in the requested service class. Search for.
Then, the or calculated channel is unused channels
Confirm with the empty / occupied table and reply the result to the request source. Therefore, when a connection using a plurality of QoSs is set in a line having a plurality of VPIs and a plurality of QoS connections are shared by one VPI, each VPI needs to be set for each VPI according to the environment to be used. can assign connections to prioritize QoS to be used, it is possible to expect the efficient use of bandwidth in accordance with the result, use purposes. Embodiments of the present invention will be described below in detail with reference to the drawings. << Specific Example 1 >><Configuration> FIG. 1 is a configuration diagram showing a main part of the switching system of the present invention. Prior to this description, the overall configuration will be described. FIG. 2 is a configuration diagram of a network system to which the switching system of the present invention is applied. The illustrated system comprises a terminal 1, an exchange 2, a terminal line 3, an exchange 4, a trunk line 5, a terminal 6, a terminal line 7, and maintenance consoles 8, 9. The terminals 1 and 6 are, for example, an interface unit having an ATM terminal or an ATM interface. The terminal 1 is connected to the exchange 2 via the terminal line 3, and the terminal 6 is connected to the exchange 4 via the terminal line 7. I have. Exchange 2,
Reference numeral 4 denotes an ATM switch for switching cells in the ATM network, and these switches 2 and 4 are connected via a trunk line 5. here,
The terminals 1 and 6 and the exchanges 2 and 4 are connected by, for example, a UNI (User Network Interface) defined by an ATM forum, and the exchanges 2 and 4 are also connected by a P-NNI (Private Network to Network Interface) defined by the ATM forum.
rface). The maintenance consoles 8 and 9 are connected to the exchanges 2 and 4, respectively, and receive the PVCs between the terminals 1 and 6 and the exchanges 2 and 4 and between the exchanges 2 and 4 according to the input of an operator's command or the like. This is for making a setting request. In such a network configuration, communication is performed between the terminal 1 and the terminal 6 by SVC and PVC. At this time, the communication in the SVC is performed between the exchanges 2 and 4 and the terminals 1 and 6, the exchange 2,
VPI and VCI are automatically captured between the four. Also, P
In the VC communication, the operator checks the unused VPI and VCI from the maintenance consoles 8 and 9 by operating commands and the like, and specifies the checked VPI and VCI to perform connection setting. When making such a connection setting,
In this specific example, one channel does not compete between SVC and PVC, and this configuration will be described with reference to FIG. The block shown in FIG. 1 shows the functional blocks in the exchanges 1 and 4 in FIG. 2, and comprises an SVC control unit 11, a PVC control unit 12, and a channel management unit 13. The maintenance console 8 (9) is the maintenance console described with reference to FIG. The SVC control unit 11 sends a request for capturing a channel to be used to the channel management unit 13 every time communication is started to an arbitrary partner, and sets a channel to the arbitrary partner based on a response to the request. It has the function of making the other party selection connection. Further, the PVC control unit 12 sends a capture request for a channel to be used to the channel management unit 13 before starting communication with the arbitrary partner to the channel management unit 13, and based on the response to the request, the channel to the arbitrary partner is fixed. It has a function to make a fixed connection with the other party to be set. The channel management unit 13 manages the occupancy of the channel to be used, searches for a free channel in response to a channel capture request from the SVC control unit 11 and the PVC control unit 12, and searches for a free channel. Has a function of responding to the requesting control unit, and has a channel vacancy table 14 for managing the vacancy of the channel to be used. FIG. 3 is an explanatory diagram of the channel vacancy table.
The channel empty / busy table 14 is a table in which the row direction corresponds to the VPI number and the column direction corresponds to the VCI number. In the figure, “1” indicates unused (empty) and “0” indicates in use. ing. The channel vacancy table 14 shows a case where one path is constituted by 16 channels. The channel management unit 13 is provided with the SVC control unit 11
When a channel capture request is received from the controller, a free channel is searched from the youngest number of the channel empty / busy table 14 and, when a channel capture request is received from the PVC control unit 12, an empty channel is searched from the oldest number. <Operation> The channel management unit 13 receives a channel capture request from the SVC control unit 11 or the PVC control unit 12 (see (1) in FIG. 1), and the channel number is explicitly specified in the parameter in the request. If it is designated as, the vacancy of the channel is confirmed with reference to the channel vacancy table 14, and the result is output. In FIG. 1, channel numbers 1 and 2 indicate a channel on one side and a channel on the other side for switching. On the other hand, if the channel number is omitted from the parameter during the channel capture request, the communication type of the parameter is recognized. If this is SVC, the unused VPI and VCI in the channel vacancy table 14 are used starting from the lowest number. Search for (empty) channels. That is, in the channel empty / busy table 14 of FIG. 3, a free channel is searched from the VPI and VCI No. 0, and if there is no free channel with the VPI of No. 0 to 15, the next VPI is the first VCI. To 0
Search from number. In the illustrated example, the VPI number is 1, the VCI number is
Since the number is 7 and there is an empty channel, the channel is set to “in use (= 0)”, the channel capture result is set to “OK”, and a channel capture response is output to the SVC control unit 11. If no unused (empty) channel is found as a result of the search, the channel capture result is returned as NG and a channel capture response is returned to the SVC controller 11 {in FIG.
See (2). The channel control request is sent to the PVC controller 1
2, the VPI is n-th and V
The CI searches the 15th channel in the youngest direction, and outputs the result in the same manner as the above-described SVC control unit 11. <Effects> As described above, in the specific example 1, the SV
Even if capture of VPI and VCI conflicts between the C communication and the PVC communication, the VPI and VC for PVC can be
I can be captured, and improvement in the convenience of the operator can be expected. Also, when making a channel capture request, the operator searches for an empty channel by the PVC control unit 12 and the channel management unit 13, so that the channel number can be omitted at the time of the request. From this point of view, the burden on the operator can be reduced. In the first embodiment, the ATM is used as a communication mode. However, in other communication modes, data is divided into cells, and each cell is divided into a plurality of transmission paths. Communication mode that allocates to any one of the virtual channels and transfers it, and has a partner selection connection function that captures the channel to be used each time communication starts and a partner connection function that determines the channel to use before communication starts Then, the present invention can be similarly applied to a network such as a packet switching network. << Embodiment 2 >><Configuration> FIG. 4 is a configuration diagram showing a main part of the switching system of Embodiment 2. The functions of the SVC control unit 11a and the PVC control unit 12a in the specific example 2 include QoS as a parameter when a channel acquisition request is made in addition to the functions of the SVC control unit 11 and the PVC control unit 12 in the specific example 1. . For example, as the QoS, CBR (Consta
nt Bit Rate: fixed rate service) / VBRrt (Vari
able Bit Rate real time: Real-time variable rate service / VBRnrt (Variable Bit Rate non real)
time: non-real-time variable speed service) / UBR (Un
spesified Bit Rate: Service / ABR without rate specification
(Avairable BitRate: available speed service). The channel management unit 13a is configured as follows:
And a usable QoS table 15. FIG. 5 is an explanatory diagram of an available QoS table. The available QoS table 15 is a table for presetting available QoS for each VPI. For example, in the illustrated table, if the VPI is 0, the CBR is
When the PI is No. 1, UBR is set. In other words, this indicates that the 0th VP can use only the CBR as its QoS and the 1st VP can use only the UBR. The channel manager 13a is configured as follows. That is, when QoS is included as a parameter from the SVC control unit 11a and the PVC control unit 12a, and when the channel number is omitted, the available QoS table 15 is searched, and the QoS
It is determined whether or not matches. If the QoS matches, the V in the corresponding VPI of the channel vacancy table 14
It is configured to search for a CI and output a result of capturing an empty channel. <Operation> The channel management unit 13a
Channel capture requests from the control unit 11a and the PVC control unit 12a are accepted (see (1) in FIG. 4). If the channel number is explicitly specified in the parameter, the specified VPI and QoS can be used. It is checked whether it matches the QoS table 15, and if it matches, next, it checks the channel vacancy table 14 with reference to the channel vacancy table 14. If the channel number is omitted, the communication type of the parameter is checked.
The QoS requested from the available QoS table 15
It is checked whether S matches, and if it matches, an unused (empty) channel is searched from the youngest VCI corresponding to the VPI in the channel vacancy table 14. For example, SV
If the QoS is specified as UBR as a parameter of the channel acquisition request from the C control unit 11a, the QoS matches since the available QoS table 15 is VBR number 1 is UBR. Therefore, channel vacancy table 14
Is configured as shown in FIG. 3, the VPI in the channel empty / busy table 14 is searched for the first VCI from the youngest. Here, when the VCI number 7 is confirmed as an unused channel, this channel is determined to be in use, the channel capture result is set to OK, and the channel capture response is set to the SVC control unit, as in the first embodiment. Return to 11a {see (2) in FIG. 4}. When the communication type is PVC,
It checks whether the QoS matches the available QoS table 15 from the oldest VPI, and if it matches, searches for an unused channel in the channel occupancy table 14 from the oldest VCI. Note that the QoS of the request source can be used.
5 is not available, and QoS is available.
If there is no unused channel in the corresponding VPI even if it matches 5, the channel management unit 13a sets the channel capture result to NG and returns this channel capture response to the request source. <Effects> As described above, in the specific example 2, when a connection using a plurality of QoSs is set on a line having a plurality of VPIs, the QoS used for each VPI can be assigned. In the ATM network, it is possible to expect efficient use of the bandwidth according to the purpose of use. For example, in a certain line, the VPI used in the CBR is specified, and the band used is limited, so that the band used by the voice on the line can be limited. This can be easily realized by specifying the VPI used in the CBR in the available QoS table 15. << Embodiment 3 >><Configuration> FIG. 6 is a configuration diagram showing a main part of the switching system of Embodiment 3. First, the SVC control unit 1 in the specific example 3
The functions of 1a and the PVC control unit 12a are the same as those of the second embodiment. Next, the channel management unit 13b has the same channel empty / busy table 14 as in the first and second embodiments, and also has a priority-enabled QoS table 16. FIG. 7 is an explanatory diagram of the available QoS table 16 with priority. This priority-enabled QoS table 16 is:
It is a table in which QoS available for each VPI is set with a priority. For example, in the illustrated table, the VPI
Is assigned a priority in the order of CBR, VBR, UBR, ABR. That is, this is the 0th VP
Indicates that CBR can be used as the QoS with the highest priority, and in the following, the order is VBR, UBR, ABR. The channel management section 13b is configured as follows. That is, when QoS is included as a parameter from the SVC control unit 11a and the PVC control unit 12a, and when the channel number is omitted, the available QoS table 16 with priority is searched and the specified QoS is specified. , The VCI in the channel occupancy table 14 of the selected VPI is searched, and the result of capturing an empty channel is output. <Operation> The channel management unit 13b
If channel acquisition requests from the control unit 11a and the PVC control unit 12a are received and the channel number is explicitly specified in the parameter, the specified VPI and QoS are specified.
Matches any of the priorities on the available QoS table 16 with priority, and if so, refers to the channel vacancy table 14 to confirm the vacancy of the channel. If the channel number is omitted, the communication type of the parameter is checked.
Check whether the requested QoS matches the first priority on the priority-enabled QoS table 16 from the lowest number of I, and if so, the VPI in the channel busy table 14
Of unused (empty) channels from the youngest VCI corresponding to. For example, when the QoS is specified as ABR as a parameter of the channel acquisition request from the SVC control unit 11a, the available QoS with priority table 16
Since the VPI with the highest ABR priority is No. 2, the VPI in the channel vacancy table 14 is searched for the second VCI from the youngest. As a result, when an unused channel is found, the corresponding channel section of the channel vacancy table 14 is set to “in use”, and the channel capture result is set to “OK”.
And returns a channel capture response to the SVC controller 11a. When the communication type is PVC,
It is checked whether the QoS matches the first priority on the priority-enabled QoS table 16 from the VPI's oldest number, and if it matches, the unused channel of the channel occupancy table 14 is determined from the VCI's oldest number. Search for. If no unused channel is found with the first priority, the priority is lowered and the above operation is repeated. If no unused channel is found in any of the priorities, the channel acquisition result is set to NG.
And returns this channel capture response to the request source. <Effects> As described above, in the specific example 3, in a line having a plurality of VPIs, a connection using a plurality of QoSs is set, and one VPI shares a plurality of QoS connections. According to the environment to be used, it is possible to prioritize the QoS to be used for each VPI and allocate the connection, and therefore, it is possible to expect efficient use of the band according to the purpose of use in the ATM network. For example, it is possible to adopt a form in which voice is used preferentially by giving priority to CBR in the VPI of a certain line, and use in a data system is permitted only when there is an available band. In the specific examples 2 and 3, the case of the ATM as the communication mode has been described. However, even in the other communication modes, the data is divided into cells, and
In a communication mode in which each cell is assigned to any one of a plurality of virtual channels on a transmission path and transferred, if the acquisition of channels is controlled according to a service class that defines a service related to speed, for example, a packet switching network is used. It is applicable even in a network.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a main part configuration diagram of a specific example 1 in the exchange system of the present invention. FIG. 2 is a configuration diagram of a network system to which the switching system of the present invention is applied. FIG. 3 is an explanatory diagram of a channel empty / busy table in the switching system of the present invention. FIG. 4 is a main part configuration diagram of a specific example 2 in the exchange system of the present invention. FIG. 5: Available QoS in the switching system of the present invention
It is explanatory drawing of a table. FIG. 6 is a main part configuration diagram of a specific example 3 in the exchange system of the present invention. FIG. 7 is an explanatory diagram of an available QoS table with priority in the switching system of the present invention. [Description of Signs] 11, 11a SVC control unit 12, 12a PVC control unit 13, 13a, 13b Channel management unit

Claims (1)

(57) [Claims] [Claim 1] Data is divided into cells, respectively.
In a communication mode switching system in which each cell is allocated to any one of a plurality of virtual channels on a transmission path and transferred, a request to capture a virtual channel to be used is made every time communication is started with an arbitrary party. An SVC control unit for performing a peer selection connection for setting a virtual channel to the arbitrary party based on the response to the virtual channel to be used, and a virtual channel to be used before starting communication with the arbitrary party. sends a capture request, based on the response to this, the PVC control section for permanent virtual circuit to set the virtual channel to the arbitrary counterpart fixed, said plurality of virtual channels a predetermined order in array I
Channel occupancy table and the plurality of virtual channels
A service class that defines services related to transfer speed
Having a priority-enabled QoS table indicating the priority,
Any service request from SVC control unit and PVC control unit
If there is a request for use in Lass, it can be used with the above priority
Search the QoS table and find the priority in the requested service class
Search for virtual channels in descending order of
Check the channel vacancy table in the channel vacancy table, and
A switching system comprising: a channel management unit that responds to the requesting control unit if the channel is a channel.