JP2003204351A - Exchange system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To catch VPI and VCI for PVC with a single request for setting of PVC even if the catch of SVC communication and that of VPI and VPI compete with each other. <P>SOLUTION: An SVC controller 11 requests the catch of a channel to be used in a channel controller 13 each time when initiating communication. A PVC controller 12 requests the channel controller 13 to catch a channel to be used when initiating communication. The channel controller 13 controls the vacancy/engagement of all virtual channels to be used, and in case that there is a channel catch request from either the SVC controller 11 or the PVC controller 12, it searches a vacant channel using a channel vacancy/occupation table 14, and in case that a vacant channel is found, this outputs it to the controller at the request source. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to, for example, an ATM (As
ynchronous Transfer Mode), such as a communication mode switching system that divides data into cells and assigns each cell to one of a plurality of virtual channels of a transmission path for transfer.

[0002]

2. Description of the Related Art As a communication method used in an ATM network, there is an SVC (Switched Virtual Connection) in which a partner is designated and connected each time communication is started. That is, this SVC is
This is a communication method in which (Virtual Channel) is set to connect with the other party. On the other hand, such SVC
On the other hand, 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 the communication with the other party is started, and the connection with the other party is fixedly performed by the obtained VC.

[0003]

However, when the connection is set by the above communication method, there are the following problems.

When setting up a PVC connection,
According to SVC, VPI (Virtual Path Identifier) and VCI (Virtual Channel Identifie)
r: virtual channel identifier)) changes from time to time, so after the operator investigates the unused VPI and VCI,
It is possible that the VPI and VCI will be used in SVC. Therefore, the operator can use the above-mentioned V for PVC communication.
If PI and VCI are specified and a connection is set up, the connection cannot be set up.

In an ATM network, CBR (Cons
tant Bit Rate: Fixed speed service) and VBR (Variab)
le Bit Rate: QoS (Quality of Servi) that defines services related to transmission speed, such as variable speed service.
ce: quality of service class) is provided. However, if such multiple connections are
When setting on a line with PI, VPI is used in the order of connection setting request, so a specific Qo
A situation occurs in which only S occupies the band,
There is a problem that it hinders efficient use. For example, when a request for setting a CBR connection used for voice is continuously generated, there is a possibility that another QoS connection cannot be set.

From this point of view, SVC communication and VPI,
Even if there is a conflict in VCI acquisition, P can be set with one PVC setting request.
Realization of a switching system that can capture VPI and VCI for VC, improve the convenience of the operator, and efficiently use the bandwidth according to the purpose of use of the network Was desired.

[0007]

The present invention adopts the following constitution in order to solve the above-mentioned problems. <Structure of Claim 1> The present invention divides data into cells, allocates each cell to any one of a plurality of virtual channels of a transmission line, and transfers the cells. Each time communication is started, a request to capture the virtual channel to be used is sent, and based on the response to the request, the SVC control unit that performs connection selection connection to set a virtual channel to an arbitrary partner and the arbitrary partner. On the other hand, before the start of communication, a request for capturing a virtual channel to be used is sent out, and based on a response to the request, a PVC control unit for performing a permanent connection with a virtual channel to fixedly set a virtual channel to an arbitrary remote party and a virtual controller to be used. It has a channel free / busy table in which channels are arranged in a predetermined order, and when a channel acquisition request is received from the SVC control unit and the PVC control unit, the channel free / busy table is received. Perform a search for available channel from different directions against sequences, characterized by comprising a channel management unit which detects a free channel.

<Explanation of Claim 1> The communication mode targeted by the invention of Claim 1 is, for example, ATM, but other than this, the data is divided into cells, and each cell is transmitted. In a communication mode that assigns and transfers to any of multiple virtual channels on the road, 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 Any of the above can be similarly applied.

The SVC control section sends a channel acquisition request to the channel management section each time communication is started. Further, the PVC control unit, if a channel number is designated to the channel management unit based on the channel acquisition request from the operator, determines whether the channel is empty or omits the channel number. If there is, an empty channel search request is sent.

The channel availability table of the channel management unit is a table in which the row direction corresponds to the VPI number and the column direction corresponds to the VCI number, for example, but other arrangements may be used. Then, when a channel acquisition request is issued, the channel management unit searches this channel free / busy table from the smallest number in the case of the SVC control unit and from the oldest number in the case of the PVC control unit, but the retrieved parts are duplicated. If the search is performed from different directions so as not to do so, the search may be performed from the middle part of the array to the front direction and the back direction, for example. With such a configuration, even if a channel acquisition request is issued from the SVC control unit and the PVC control unit, it is possible to extract an empty channel in a short time.

As described above, since all channel management is performed by the channel management unit, as in the conventional case, the operator investigates the unused VPI for the VCI and then uses the VPI and VCI in the SVC. Therefore, even if there is a conflict between the SVC communication and the acquisition of VPI and VCI, a single PVC setting request will cause a V
PI and VCI can be captured.

<Structure of Claim 2> In the exchange system according to Claim 1, an available QoS table in which a channel to be used is set for each service class that defines a service relating to a transfer rate, an SVC control unit and a PVC control unit. If there is a usage request from any service class from the, the available QoS table is searched, and if the requested service class matches, the availability of the matched channel is confirmed in the channel availability table, and the available channel is checked. If there is, the switching system is provided with a channel management unit that responds to the request source control unit.

<Explanation of Claim 2> The service class covered by the invention of Claim 2 is, for example, CBR / VBRrt / VBRnrt / UBR / AB in the ATM switching system.
Although it is a service class such as R, other services can be similarly targeted as long as they define a service related to transfer speed.

The channel management unit includes an SVC control unit and a P
When there is a request for use in an arbitrary service class from the VC control unit, first, the usable QoS table is searched. As a result, when the requested service class matches, the channel availability table is searched to see if the matched channel is unused, and the result is returned to the requester as in the first aspect of the invention.

Therefore, when a connection using a plurality of QoS is set in a line having a plurality of VPIs, it is possible to allocate the QoS to be used for each VPI, and as a result, the bandwidth according to the purpose of use in the communication network can be allocated. Expected to be used efficiently.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. << Specific Example 1 >><Structure> FIG. 1 is a structural diagram showing a main part of the exchange system of the present invention. Prior to this description, the entire structure will be described.

FIG. 2 is a block diagram of a network system to which the exchange system of the present invention is applied. The system shown in the figure comprises a terminal 1, an exchange 2, a terminal line 3, an exchange 4, a relay line 5, a terminal 6, a terminal line 7, and maintenance consoles 8 and 9. The terminals 1 and 6 are, for example, an ATM terminal or an interface unit having 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. There is. Exchange 2,
Reference numerals 4 are ATM exchanges for switching cells in the ATM network, and the exchanges 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 in the ATM forum, and the exchanges 2 and 4 are also connected to the P-NNI (Private Network to Network Interface) defined in the ATM forum.
rface) is connected.

The maintenance consoles 8 and 9 are connected to the exchanges 2 and 4, respectively, and the PVCs between the terminals 1 and 6 and the exchanges 2 and 4 and between the exchanges 2 and 4 are input by the operator's command input. It is for making a setting request.

In such a network configuration, the terminals 1 and 6 communicate with each other by SVC and PVC. At this time, SVC communication is performed between the exchanges 2 and 4 and the terminals 1 and 6 and between the exchanges 2 and 3 by the above-mentioned UNI procedure.
Automatically capture VPI and VCI between 4 Also, P
In the VC communication, an operator investigates unused VPIs and VCIs from the maintenance consoles 8 and 9 by operating a command or the like, and specifies the investigated VPIs and VCIs to establish a connection.

When making such a connection setting,
In this specific example, one channel does not conflict between SVC and PVC, and this configuration will be described with reference to FIG.

The blocks shown in FIG. 1 are the functional blocks in the exchanges 1 and 4 in FIG. 2, and are composed of an SVC control unit 11, a PVC control unit 12, and a channel management unit 13. Further, the maintenance console 8 (9) is the maintenance console described in FIG.

Each time the SVC control unit 11 starts communication with an arbitrary partner, it sends a request to capture the channel to be used to the channel management unit 13, and based on the response to this, sets the channel to the arbitrary partner. It has the function of selecting and connecting to other parties. Further, the PVC control unit 12 sends a request to capture a channel to be used to the channel management unit 13 before starting communication with an arbitrary partner, and based on a response to the request, fixes the channel to the arbitrary partner. It has a function to establish a fixed connection with the other party.

The channel management unit 13 manages the availability of channels to be used, searches for an empty channel in response to a channel acquisition request from the SVC control unit 11 and the PVC control unit 12, and when there is an empty channel. Has a function of responding to the request source control unit, and is provided with a channel availability block 14 for managing availability of the channels used.

FIG. 3 is an explanatory diagram of the channel open / close table.
The channel open / close 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 availability table 14 shows the case where one path is composed of 16 channels.

The channel management unit 13 includes the SVC control unit 11
When a channel acquisition request is received from the channel free / busy table 14, an empty channel is searched from the oldest number in the channel free / busy table 14, and when a channel acquisition request is received from the PVC control unit 12.

<Operation> The channel management unit 13 receives a channel acquisition request from the SVC control unit 11 or the PVC control unit 12 (see (1) in FIG. 1), and the channel number is explicitly set in the parameter in the request. If it is specified to, the channel open / close table 14 is referred to, the open / close state of the channel is confirmed, and the result is output. In FIG. 1, channel numbers 1 and 2 indicate one side channel and the other side channel for switching.

On the other hand, if the channel number is omitted in the parameter in the channel acquisition request, the communication type of the parameter is recognized, and if this is SVC, the VPI and VCI in the channel open / close table 14 from the smallest number to the unused state. Search for an (empty) channel. That is, in the channel open / close table 14 of FIG. 3, a free channel is searched from VPI and VCI No. 0, and if there is no free channel in VPI 0 to VCI 0 to 15, the next VPI is No. 1 VCI. 0
Search by turn. In the illustrated example, the VPI number is 1 and the VCI is
Since the number is 7 and there is an empty channel, the channel is set to “in use (= 0)”, the channel acquisition result is set to OK, and the channel acquisition response is output to the SVC control unit 11. If no unused (empty) channel is found as a result of the search, the channel acquisition result is returned as NG and a channel acquisition response is returned to the SVC control unit 11 (in FIG. 1,
See (2)}.

The channel control request is sent by the PVC control unit 1.
If it is from 2, VPI is n, V in the illustrated example.
The channel with the CI number 15 is searched in the lower direction, and the result is output in the same manner as the SVC control unit 11 described above.

<Effect> As described above, in the specific example 1, the SV
Even if the C communication and the PVC communication compete for the VPI and VCI acquisition, one PVC setting request can be used for the PVC VPI and VC.
I can be captured, and the convenience of the operator can be expected to improve. In addition, even when the operator makes a channel acquisition request, the PVC control unit 12 and the channel management unit 13 search for an empty channel, so the channel number can be omitted when making the request. From the point of view, it is possible to reduce the burden on the operator.

In the first specific example described above, the case of using ATM as the communication mode has been described. However, even in communication modes other than this, data is divided into cells and each cell is divided into a plurality of transmission lines. A communication mode that allocates and transfers to any of the virtual channels of the other, and has a partner selection connection function that captures the channel to be used each time when communication starts and a partner fixed connection function that determines the channel to use before communication starts If so, the same is applicable to a network such as a packet switching network.

<< Specific Example 2 >><Structure> FIG. 4 is a block diagram showing a main part of the exchange system of the specific example 2. In FIG. The functions of the SVC control unit 11a and the PVC control unit 12a in the second specific example include the functions of the SVC control unit 11 and the PVC control unit 12 in the first specific example, and QoS as a parameter when making a channel acquisition request. . For example, as its QoS, CBR (Consta
nt Bit Rate: Fixed speed service / VBRrt (Vari
able Bit Rate real time: Real-time variable speed service / VBRnrt (Variable Bit Rate non real)
time: Non-real time variable speed service) / UBR (Un
spesified Bit Rate: Service / ABR without specified speed
(Avairable BitRate: available speed service).

In addition, the channel management unit 13a has a specific example 1
In addition to the channel blockage table 14 similar to the above, the available QoS table 16 is provided.

FIG. 5 is an explanatory diagram of the usable QoS table. The available QoS table 16 is a table for presetting available QoS for each VPI. For example, in the illustrated table, when VPI is 0, CBR is V
When the PI is No. 1, UBR is set. That is, this indicates that the 0th VP can use only CBR as its QoS, and the 1st VP can use only UBR.

The channel management unit 13a is constructed as follows. That is, when QoS is included as a parameter from the SVC control unit 11a and the PVC control unit 12a, and the channel number is omitted, the available QoS table 16 is searched and the QoS is determined.
It is determined whether or not match. When the QoS matches, V in the corresponding VPI of the channel blockage table 14
It is configured to search for a CI and output a capture result of an empty channel.

<Operation> The channel management unit 13a uses the SVC
Accepts a channel capture request from the control unit 11a and the PVC control unit 12a (see (1) in FIG. 4), and if the channel number is explicitly specified in the parameter, the specified VPI and QoS can be used. It is confirmed whether the QoS table 16 is met, and if they match, then the channel open / close table 14 is referred to, and the open / close state of the channel is confirmed.

If the channel number is omitted, the communication type of the parameter is confirmed, and if SVC, VP
QoS requested in the available QoS table 16 from I's youngest number
It is confirmed whether S matches, and if they match, an unused (empty) channel is searched from the youngest VCI corresponding to the VPI in the channel open / close table 14. For example, SV
When the QoS is specified as UBR as the parameter of the channel acquisition request from the C control unit 11a, the QoS matches because the first VPI is UBR in the available QoS table 16. Therefore, the channel blockage table 14
Is configured as shown in FIG. 3, the VCI having the first VPI in the channel blockage table 14 is searched from the youngest VCI. Here, when the VCI number 7 is confirmed as an unused channel, it is determined that this channel is being used and the channel capture result is OK, and the channel capture response is the SVC control unit, as in the first specific example. It is returned to 11a {see (2) in FIG. 4}.

If the communication type is PVC,
From the VPI old number, it is confirmed whether the QoS matches the available QoS table 16. If they match, the VCI old number is searched for an unused channel in the channel availability table 14.

The requesting QoS can be used. QoS table 1
If not, then QoS is also available QoS Table 1
Even if it matches with 6, if there is no unused channel in the corresponding VPI, the channel management unit 13a sets the channel capture result to NG and returns this channel capture response to the request source.

<Effect> As described above, in the specific example 2, when a connection using a plurality of QoS is set in a line having a plurality of VPIs, it is possible to allocate the QoS to be used for each VPI. It is possible to expect efficient use of a band according to the purpose of use in the ATM network.

For example, in a certain line, the VPI used in the CBR is specified and the band is limited, whereby the voice use band on the line can be limited. This can be easily achieved by specifying the VPI used in CBR in the available QoS table 16.

In the specific example 2, the case where the ATM is used as the communication mode has been described. However, even in the communication modes other than this, data is divided into cells, and each cell is divided into a plurality of transmission lines. Applicable to any network, such as a packet-switched network, as long as it controls the channel acquisition according to the service class that defines the service related to speed in the communication mode in which it is assigned to any of the virtual channels of Is.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part of a first specific example in an exchange system of the present invention.

FIG. 2 is a configuration diagram of a network system to which the exchange system of the present invention is applied.

FIG. 3 is an explanatory diagram of a channel open / close table in the exchange system of the present invention.

FIG. 4 is a configuration diagram of a main part of a second specific example in the exchange system of the present invention.

FIG. 5: Usable QoS in the switching system of the present invention
It is an explanatory view of a table.

[Explanation of symbols]

11, 11a SVC control unit 12, 12a PVC control unit 13, 13a Channel management unit

Claims (2)

[Claims] 1. Dividing data into cells,
In a switching system in a communication mode in which each cell is assigned to one of a plurality of virtual channels of a transmission line and transferred, a request to capture a virtual channel to be used is sent every time communication is started to any other party. On the basis of the response to the SVC, the SVC control unit which performs the partner selection connection for setting the virtual channel to the arbitrary partner, and sends the acquisition request of the virtual channel to be used to the arbitrary partner before the communication is started. Based on a response, it has a PVC control unit for performing a permanent virtual connection to fixedly set a virtual channel to the arbitrary destination, and a channel availability table in which virtual channels to be used are arranged in a predetermined order, When a channel acquisition request is received from the SVC control unit and the PVC control unit, an empty channel is detected from a different direction in the arrangement with respect to the channel availability table. A switching system comprising: a channel management unit that searches for a free channel. 2. The switching system according to claim 1, wherein the channel management unit further includes an available QoS table in which a virtual channel to be used is set for each service class that defines a service related to a transfer rate. When there is a use request in an arbitrary service class from the control unit and the PVC control unit, the usable Qo
The S table is searched, and if the requested service class matches, the channel availability table is used to confirm the availability of the matched channel, and if it is an empty channel, it is returned to the requesting control unit. A characteristic exchange system.