JP3280046B2 - Switching system, switching device, and control method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching system, a switching device, and a control method thereof.

[0002]

2. Description of the Related Art At present, circuit switching services and packet switching services are provided as switching services for data communication in a public network. The former is DDX-C (circuit switching service), and the latter is DDX-P (first type). Switching services such as packet switching service), DDX-TP (second type packet switching service), and ISN-P (ISDN packet switching service) have been put to practical use. In particular, packet-switched services are more
It has the following features.

Since the communication network between different speed terminals has a storage and switching function, data communication can be performed even when the communication speed between the terminals is different.

[0004] Communication between terminals of different procedures When the network exchanges communication procedures, data communication can be performed between terminals of different procedures.

[0005] Packet multiplex communication By changing destination information, communication with a plurality of partners can be performed using one physical line.

Detour path selection function Even if a relay line or the like fails during communication, another path in the network can be selected based on the destination information.

[0007] Information amount charging This is a charging method according to the information amount (packet data).

[0008] From the above characteristics, in recent years, the packet switching service has been used in conversational data communication such as personal computer communication and various reservation systems regardless of terminals of different speeds and different procedures. In the INS-P described above, the packet switching service can be used not only on the Bch information channel but also on the Dch control channel.

One of the features of the packet communication in the Dch is a terminal multiplexing function which cannot be used in the conventional packet switching service. This means that up to eight terminals can be connected to one physical line, and the line can be used effectively.

[0010] Further, it is also possible to perform packet communication with a plurality of parties, such as three-party communication and conference communication in circuit switching, using the multiplex communication function.

Further, as a calling operation in packet communication, there are a method in which a caller directly dials an address (telephone number or the like) of a callee and a method in which an address is input from a terminal.

[0012]

However, in the above conventional example, packet communication is performed simultaneously with a plurality of parties such as three-party communication and conference communication using a packet switching service. When the number of participants increases, such as when playing a game, the following drawbacks occur in proportion to the number.

[0013] Since a call setting procedure is required among all the participants, the operation becomes complicated and the call setting procedure becomes complicated.

Since the same data is transmitted to a plurality of communication partners, the real-time property of the data is impaired.

In order to realize the above, a special function is required for the upper layer protocol of the terminal, and a general packet terminal cannot perform simultaneous communication with a plurality of communication partners.

In order to realize the above, it is necessary to multiplex the line on the terminal side, a plurality of resources on the terminal side (extension side) are used, and the load on the packet handler for exchanging packet data increases. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been made in consideration of a call when a communication device communicates with a communication partner device.
The purpose is to reduce the setting procedure . Also communication
If there is a link already set up to the partner device
In that case, the purpose is to use the link effectively.

[0018]

According to the present invention, there is provided an exchange system having a communication device and an exchange device to which the communication device can be connected, wherein the communication device includes a plurality of communication partner devices. And a transmitting unit for transmitting one communication request packet including the address of the communication request packet, the receiving unit receiving the communication request packet transmitted by the transmitting unit, and the communication request packet received by the receiving unit. A determination unit configured to determine, for each of the plurality of communication partner devices, a setting state of at least a part of a link to the communication partner device when starting communication with the communication partner device designated by: And the communication partner device for which at least a part of the link has been already set by the judgment means has already been set. The present invention provides a switching system and a control method therefor, characterized in that communication is performed using a link, and a new link is set and communicated with the communication partner device for which a link has not been set by the judgment means. .

Also, when receiving means for receiving a communication request packet including addresses of a plurality of communication partner devices, and when starting communication with the communication partner device specified by the communication request packet received by the receiving means, In addition,
At least a portion of the setting state of the links to the signal destination device, and a discriminating means for discriminating for each of the plurality of communication partner device, at least a part of the link has already been set by said discrimination means Communicates with the communication partner device determined to be using the already set link, and newly sets a link with the communication partner device determined that the link is not set by the determination unit. Provided is an exchange device characterized by communication and a control method therefor.

[0020]

[0021]

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic block diagram showing the configuration of a private branch exchange in the embodiment. In the figure, 100 is a private branch exchange body, 101 is an ISDN network, and 102 is an ISD
An ISDN external line interface connected to the N network 101,
103 is a channel switch for connecting each interface;
104 and 105 are packet terminals; 106 is a packet handler module (hereinafter referred to as "PHM") which is a packet switching means; 107 is connection control of the speech path switch 103 and connection with each interface 102, 109 and PHM 106; A central control unit (hereinafter, referred to as “CC”) 108 for transmitting and receiving control signals and data, etc.
C107 and each interface 102, 109 and PHM
106, and transmission paths for control signals and data transmitted and received between them.
5 is connected to the ISDN extension interface (hereinafter, referred to as
"ISDN extension interface") and 1
Reference numeral 10 denotes a storage unit including first and second storage areas.

FIG. 2 is a packet format showing a call request packet (CR) or a call reception packet (CN) in this embodiment. As shown in the figure, in the user data portion of the packet, a calling user address length, a called user address length 24, a called user address portion 25, and a calling user address portion 26 are respectively defined.
3 or a conference communication is performed in accordance with the data coded in. For example, the packet terminal 104 shown in FIG.
Performs a three-party communication with another packet terminal via the ISDN 101, a logical link is established as shown in FIG. Here, the logical links between A and B, between A and C, and between B and C correspond to the logical channel group numbers (LCGs) shown in FIG.
N: 4 bits) 21 and logical channel number (LCN: 8)
Bit 22).

FIG. 4 shows a packet format showing a data packet (DT), and the packet size differs depending on contract conditions. FIG. 5 is a packet format showing a recovery request packet (CQ) or a disconnection instruction packet (CI).

Next, referring to the sequence diagram shown in FIG. 6 and the flowcharts shown in FIG. 7 and FIG. Will be described.

First, CC1 of exchange A100 shown in FIG.
The call setting process performed by the 07 will be described. When the ISDN extension interface 109 receives a call request from the packet terminal 104, in order to transmit packet data,
A data link (layer 2) is established with the ISDN extension interface 109 (step S101), and CC1
07 is notified. In response, the CC 107 determines whether the request is a Dch packet (step S10).
2) In the case of a Dch packet, the transmission path 108 is used,
In the case of a Bch packet, the ISDN extension interface 109 and the communication path 103 are connected (step S10).
3). Thereafter, when the ISDN extension interface 109 receives a CR (call request) packet from the packet terminal 104, the ISDN extension interface 109 transmits the CR packet to the PHM 106 through the transmission path 108 (the Bch packet is the communication path 103) (step S104). Then, the PHM 106 transmits to the CC 107 through the transmission line 108, and the CC 107
The destination address, facility, call user data, and the like coded in the packet are analyzed (step S105). Next, it is determined whether or not the communication is a three-party communication based on the value of the called user address length 24 in the CR packet (step S106). If the called address length 24 is not "0", the normal calling process is performed. Perform (Step S
123). However, when the destination address length 24 is “0”,
Recognize as three-party communication, call / user / CR in CR packet
The plurality of communication partner addresses coded in the data unit 27 are stored in the second storage area of the storage unit 110 (Step S107).

Next, a CR packet is created for each of a plurality of communication partners coded in the call user data section 27, and the destination address of the transmission destination is coded in the called user address section 25 of each CR packet. (Step S108). Then, it is determined whether or not the call is an extension call from the destination address (step S109). If the call is an extension call, the CR packet is converted to a CN (call) packet, and the logical channel group number (LCGN) and the logical channel number ( LCN) is set (step S110).
Then, the data link between the extension packet terminal 105 and the ISDN extension interface 109 is checked (step S1).
11) It is determined whether a link has been set (step S112). As a result, if it is not set, the data link setting is instructed to the ISDN extension interface 109 to establish the data link (step S113). Next, the above-mentioned CN (incoming call) packet is transmitted to the PHM 106, and the PHM 106
Transmission to the DN extension interface 109 (step S
114). Then, the ISDN extension interface 109
Transmits the CN packet to the packet terminal 105a (step S115), repeats the processing in steps S108 to S115 described above (step S116), and similarly terminates the call setting processing for the packet terminal 105b.

On the other hand, if it is determined in step S109 that the call is not an extension call, the packet terminal 301 of the exchange B and the packet terminal 302 of the exchange C shown in FIG.
In order to perform user communication, LCGN and LCN contracted in advance with the ISDN network are coded as header information in the CR packet (step S117). And I
The data link between the SDN external line interface 102 and the ISDN 101 is checked (step S118), and it is determined whether the link has been set up (step S119).
Here, if not set, the data link setting is instructed to the ISDN external line interface 102,
A data link is established (step S120). next,
The above-mentioned CR packet is transmitted to the PHM 106, and the PHM
106 transmits the CR packet to the ISDN external line interface 102 (step S121). And I
The SDN external line interface 102 transmits the CR packet to the ISDN network 101 (step S122), and repeats the above-described processing in steps S108 to S122 twice (step S116).
Then, the process of setting a call to the packet terminal 302 is completed.

Next, the ISDN external line interface 102
Receives two CC (call setup completed) packets from the ISDN 101, the two CC packets are
6 to the CC 107. And PHM1
06, the two X.X. 25 PLP (Packet Layer Protocol) is established. Next, one CC packet is sent from CC 107 to PHM 106,
C. The X.C. 25 PLP is established. Then, after the CC packet is transmitted from the PHM 106 to the ISDN extension interface 109 and further transmitted to the originating packet terminal 104, a data transfer phase between the ISDN network 101 and the packet terminal 104 is performed.

Here, the data transfer phase in the three-party communication shown in FIG. 3 will be described. When ISDN extension interface 109 receives a DT (data) packet from packet terminal 104, ISDN extension interface 109 transmits the DT packet to PHM 106. Here, the PHM 106 analyzes the header information of the DT packet (octets 1 to 3 shown in FIG. 4),
It recognizes that the packet terminal 104 that has transmitted the DT packet is performing three-party communication. Then, the header information of the DT packet is changed to the LCGN, LCN of the communication partner (on the logical link with the exchanges B and C), and the DT packet is transmitted to the transmission line 1.
08 (in the case of a Bch packet, the communication path 103), and is transmitted to the ISDN external line interface 102. PHM
106 repeats the above process twice for exchanges B and C, and
The T packet is transmitted to the ISDN 101. When receiving a DT packet from another communication partner (301 of exchange B, 302 of C), PHM 106 changes the header information of the DT packet to that of extension packet terminal 104 and transmits it.

Here, the processing for releasing the call of the corresponding logical channel will be described. First, when ISDN extension interface 109 receives the CQ (recovery request) packet from the packet terminal 104, a CQ packet using transmission path 108 (Bch packet communication path 103) PHM
Send to 106. The PHM 106 transmits a CQ packet received using the transmission path 108 to the CC 107,
C107 analyzes the destination address, facility, call user data, etc. coded in the CQ packet (see FIG. 5). As a result, CC1
07 recognizes three-party communication when the destination address length in the CQ packet is “0”, but performs normal disconnection processing if the destination address is not “0”.

Next, the CC 107 separately transmits CQs to two communication partners (destination addresses) coded in the call user data section 27 in the CQ packet.
A packet is created, and the destination address of the destination is coded in the destination address part of each CQ packet. Then, it changes to the LCGN, LCN of the communication partner (on the logical link with B, C), and transmits the created CQ packet to the ISDN external line interface 102 to the PHM 106. Thereby, the PHM 106 transmits the received CQ packet to the ISDN external line interface 102,
The DN external interface 102 transmits the CQ packet to the IS
It transmits to the DN network 101.

The above processing is repeated twice, and then the IS
When the DN external interface 102 receives two CF (disconnection confirmation) packets from the ISDN 101,
The DN external interface 102 transmits two CF packets to the PHM 106. Then, PHM 106 transmits the CF packet to CC 107. Here, CC1
In step 07, when two CF packets for the two transmitted CQ packets are received, a CF packet is transmitted to the PHM 106 in order to transmit the CF packet to the packet terminal 104 that has activated the disconnection process. And
PHM 106 transmits the CF packet to ISDN extension interface 109, and
9 transmits the CF packet to the packet terminal 104. By the above processing, a plurality of communication partners and the packet terminal 104
X. between 25 PLP (L3) is released, and the disconnection process ends.

FIGS. 11 and 12 show the packet level protocol described above. FIG. 11 is a sequence diagram when the three-party communication shown in FIG. 3 is performed, and FIG. 12 is a sequence diagram when the three-party communication is performed between packet terminals connected to the extension of the exchange 100. . still,
FIG. 11 shows a packet between AB shown in FIG. 3 or a packet between AC.

Next, the packet level protocol of the called exchange 100 performing the above three-party communication will be described below with reference to the sequence diagram shown in FIG. 6 and the flowcharts shown in FIGS.

First, CC1 of exchange B or C shown in FIG.
The call setting process performed by the 07 will be described. When the ISDN external line interface 102 receives a call setup request (SETUP) message from the ISDN 101 (step S201), the message is transmitted to the CC 107.
In the case of a Bch packet, the CC 107 connects the PHM 106 and the ISDN external interface 102 via the communication path 103 (step S203). Thereafter, when the ISDN external line interface 102 receives a CN (incoming call) packet from the ISDN network 101 (step S204), the ISDN external line interface 102 transmits the CN packet to the PHM 106 through the transmission path 108 (the Bch packet is the communication path 103), and the PHM 106
Is transmitted to the CC 107 (step S205). CC1
07 analyzes the destination address, facility, call user data, and the like coded in the CN packet (step S206), and determines whether or not a three-party communication is performed (step S207). Then, when the address of the communication partner is not coded in the call user data section 27 in the CN packet, a normal incoming call process is performed (step S216). However, if the address of the communication partner is coded, it recognizes that it is a three-party communication, and sets a 10-second timer (step S208).

Next, the call user in the CN packet
The address of the communication partner coded in the address unit 27 is stored in the second storage area of the storage unit 110 (Step S209). Then, the address of the communication partner continuing the packet communication stored in the first storage area of the storage unit 110 is compared with the address of the communication partner performing the three-party communication stored in the second storage area. (Step S21
0). As a result, if packet communication is already in progress (logical channel has been established between B and C in FIG. 3) (step S21)
1) Only the incoming call processing described below is performed.

Here, the ISDN extension interface 1
09 and the extension packet terminal 301 are checked, and if not set, the ISDN extension interface 109
To set a data link, and establish the data link. Next, the CN packet is transmitted to the PHM 106, and the PHM 106 transmits the CN packet to the ISDN extension interface 109, and further, the ISDN extension interface 109 transmits to the packet terminal 301. Then, when the ISDN extension interface 109 receives a CA (Incoming Call Acceptance) packet from the packet terminal 301,
The CA packet is transmitted to PHM 106. As a result, PHM 106 transmits the X.M. 25 PLP established,
A CA packet is transmitted to CC 107. Next, CC10
7 sends the CA packet to PHM 106,
X. 106 is the network side X. Establish a 25P LP and send a CA packet to the ISDN extension interface 109. Then, the ISDN extension interface 109 is connected to the ISDN 1
04, the packet terminal 301 and the ISDN 1
01 is the data transfer phase.

On the other hand, the judgment result in step S211 described above, unless during packet communications (B in FIG. 3, logical channel established between C), until the timer has been set in step S208 times out, incoming CN The destination address of the packet is compared with the address of the destination of the three-party communication (step S212). As a result (step S213), when the corresponding communication partner, the timer is stopped (Step S21 5). However, when a timeout occurs (step S214), a CR packet is created for a communication partner (destination address) for which a logical channel has not been set. Then, the destination (ie, in this example, the packet terminal 30 of the exchange C) is stored in the destination address portion of the CR packet.
Code the destination address in 2). Next,
The LCGN contracted with the DN network and the LCN are coded in the CR packet as header information, and the data link between the ISDN external interface and the ISDN network is checked. Here, if not set, the data link setting is instructed to the ISDN external line interface 102 to establish the data link. Then, the created CR packet is
HM 106 and the PHM 106 sends the CR packet to the ISDN external interface 102.
The SDN external line interface 102 transmits the CR packet to the ISDN network 101.

Thereafter, the ISDN external line interface 10
2 receives the CC packet from ISDN 101,
The CC packet is transmitted to PHM 106. PHM1
06 is two X.X. 25 PLP (Packet Layer Protocol) is established, and a CC packet is transmitted to the CC 107. Thereafter, a data transfer phase between the ISDN 101 and the PHM 106 is performed.

Next, the data transfer phase in the three-party communication will be described. First, in the exchange B or C, another communication partner (for example, the packet terminal 104 of the exchange A)
, The PHM 106 receives the DT packet from the
The packet header information is changed to that of the packet terminal 301 or 302 of the exchange B or C and transmitted. When the packet terminal 301 or 302 transmits a DT packet, upon receiving the DT packet, the packet terminal 301 or 302 analyzes header information of the DT packet (octets 1 to 3 shown in FIG. 4) and transmits the DT packet. Or 3
It is determined whether or not 02 is performing three-party communication. And 3
In the case of multi-party communication, the header information of the DT packet is changed to LCGN, LCN of the communication partner, and the
8 (in the case of a Bch packet, the communication path 103).
It transmits to the SDN external line interface 102. And
The DT packet received by the ISDN external line interface 102 is transmitted to the ISDN network 101 to perform data transfer.

Next, the cutting process will be described. First, the ISDN external interface 102 of the exchange B or C
When a CI (disconnection instruction) packet is received from the DN network 101, the CI packet is transmitted to the PHM 106 using the transmission path 108 (the Bch packet is
106 transmits the CI packet to CC 107. C
Upon receiving a CI packet in response to a disconnection request from a communication partner of the three-party communication (for example, the extension terminal 104 of the exchange A), the C 107 sets a 10-second timer. Here, when the address of the communication partner is not coded, normal disconnection processing is performed. However, if it is coded in the call user data section 27, the address of the communication partner is deleted from the first storage area. And
A CI packet is transmitted to the PHM 106, and the PHM 106 transmits the CI packet to the ISDN extension interface 109.
And the ISDN extension interface 109
The packet is transmitted to the extension packet terminal 301.

Thereafter, the ISDN extension interface 10
9 receives a CF (disconnection confirmation) packet from the packet terminal 301 or 302, and transmits the CF packet to the PH using the transmission path 108 (the Bch packet is the communication path 103).
Send to M106. Here, the PHM 106 that has received the CF packet receives the X.509 on the terminal side. 25 PLP (Layer 3) is released, and a CF packet is transmitted to CC 107. CC1
07 transmits a CF packet to the PHM 106, and the PHM 106 that has received the CF packet 25PLP
(Logical channel with A) and release the CF packet to I
It transmits to the SDN external line interface 102. And
ISDN external line interface 102
The data is transmitted to the SDN network 101, and the disconnection processing is completed.

On the other hand, the CC 107 monitors the disconnection from the communication partner that performs the three-way communication until the set timer times out, and when the timeout occurs, the communication partner with which the logical channel is established (in this example, the exchange C A CQ packet is created for the extension terminal 302). Next, the destination address of the transmission destination is coded in the destination address part of the CQ packet, and the created CQ packet is
Send to 6. Then, PHM 106 transmits the CQ packet to ISDN external line interface 102,
DN external line interface 102 sends CQ packet to ISD
It transmits to N network 101. After that, when the ISDN external line interface 102 receives the CF packet from the ISDN 101, it transmits the CF packet to the PHM 106. Here, the PHM 106 that has received the CF packet is connected to the network side (extension terminal 302 of the exchange C) X. Release 25PLP and transmit a CF packet to CC 107. CC107
Recognizes the disconnection with the communication partner (the extension terminal 302 of C),
The cutting process is completed.

FIGS. 13 and 14 show the packet level protocol described above. FIG. 13 is a sequence diagram of the exchange B shown in FIG. 3, and FIG. 14 is a sequence diagram of the exchange C. In the figure, a packet between AB shown in FIG. 3, a packet between AC, and a packet between BC shown in FIG. 3 are shown.

As described above, according to the present embodiment,
When performing packet communication simultaneously with a plurality of parties, such as three-party and conference communication, using a packet switching service in an ISDN network and a private network, the central control unit (CC)
By analyzing the packet data received from the calling terminal and the ISDN network and establishing a plurality of packet links (layer 3) with a plurality of communication partners (participants), each participant can send a plurality of packets to a plurality of communication partners. It is not necessary to perform the call setting procedure described above, and a complicated operation is omitted.

In addition, it is not necessary for the packet terminal to support the above-mentioned higher-level protocol, and the existing packet terminal can be effectively used. Further, it is not necessary to multiplex the line on the terminal side, the resources on the terminal side (extension side) can be effectively used, and the load on the packet handler for exchanging packet data is reduced.

[0049]

Next, another embodiment of the present invention will be described below with reference to the drawings.

In the above embodiment, the central control unit (CC)
Analyzes packet data received from an originating terminal and an ISDN network, establishes a plurality of packet links (layer 3) with a plurality of communication partners, and uses a packet switching service in an ISDN network and a private network to communicate with three parties. Although packet communication is performed at the same time as multiple partners like
The packet handler module (PHM) can have a similar function.

FIGS. 15 and 16 are flowcharts showing the call setting process performed by the PHM 106 in the packet level protocol (connection control procedure) when performing the three-party communication in the exchange 100 shown in FIG. FIG.
7 and 18 are flowcharts showing the call setting process performed by the PHM 106 of the exchange B or C shown in FIG. Note that these processes are basically the same as the above-described call setting process performed by the CC, and a description thereof will be omitted.

FIG. 19 is a sequence diagram when the three-party communication shown in FIG. 3 is performed, and FIG. 20 is a sequence diagram when the three-party communication is performed between the packet terminals connected to the extension of the exchange A100. FIG. FIG. 19 shows a packet between AB shown in FIG. 3 or a packet between AC. Similarly,
FIG. 21 is a sequence diagram of the exchange B shown in FIG.
FIG. 22 is a sequence diagram of the exchange C. In the drawing, packets between AB shown in FIG. 3, packets between AC, and packets between BC are shown.

According to another embodiment, the central control unit (CC)
By performing the call control process performed by the packet handler module, the load on the CC in the exchange can be reduced.

In the above-described embodiment, a description has been given of three-party communication. However, the present invention is not limited to this, and packet communication can be performed similarly to three or more communication partners.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus.

[0056]

As described above, according to the present invention,
It is possible to reduce the number of call setting procedures when starting communication . If there is a link that has already been set up to the communication partner device, the link can be used effectively.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a private branch exchange in the present embodiment.

FIG. It is a format diagram of a 25CR / CN packet.

FIG. 3 is a schematic diagram of a packet link in three-party communication.

FIG. It is a format diagram of a 25DT packet.

FIG. It is a format diagram of a 25CQ / CI packet.

FIG. 6 is a sequence diagram in three-party communication.

FIG. 7

FIG. 8 is a flowchart showing a control procedure on the calling side in the embodiment.

FIG. 9

FIG. 10 is a flowchart showing a control procedure on the called side in the embodiment.

FIG. 11

FIG. 12 is a sequence diagram on the calling side in the present embodiment.

FIG. 13

FIG. 14 is a sequence diagram on the called side in the present embodiment.

FIG.

FIG. 16 is a flowchart showing a control procedure on the calling side in another embodiment.

FIG.

FIG. 18 is a flowchart showing a control procedure on the called side in another embodiment.

FIG.

FIG. 20 is a sequence diagram on the calling side in another embodiment.

FIG. 21

FIG. 22 is a sequence diagram on the called side in another embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Private branch exchange 101 Public network 102 Outside line interface 103 Call path switch 104 Packet terminal (for transmission) 105 Packet terminal (for reception) 106 Packet handler module 107 Central control unit 108 Transmission line 109 Extension interface 110 Storage unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04L 12/56 H04L 12/02 H04L 12/18

Claims (8)

(57) [Claims] 1. An exchange system comprising a communication device and an exchange device connectable to the communication device, wherein the communication device has a transmission unit for transmitting one communication request packet including addresses of a plurality of communication partner devices. The switching device includes: a receiving unit that receives a communication request packet transmitted by the transmitting unit; and a communication device that starts communication with the communication partner device specified by the communication request packet received by the receiving unit.
, At least a portion of the setting state, and a discriminating means for discriminating for each of the plurality of communication partner device, at least a portion is already set link by said discrimination means of a link to the communication partner device The communication with the communication partner device determined to have been performed is performed using the link that has already been set, and a new link is established with the communication partner device that has determined that the link has not been set by the determination unit. A switching system characterized by setting and communicating. 2. The switching system according to claim 1, wherein said switching system is capable of storing and exchanging packet data. 3. The switching system according to claim 1, wherein said switching system is a switching system that supports switching of an ISDN (Integrated Services Digital Network). 4. Receiving means for receiving a communication request packet including addresses of a plurality of communication partner devices, and starting communication with the communication partner device specified by the communication request packet received by the receiving unit.
, At least a portion of the setting state, and a discriminating means for discriminating for each of the plurality of communication partner device, at least a portion is already set link by said discrimination means of a link to the communication partner device The communication with the communication partner device determined to have been performed is performed using the link that has already been set, and a new link is established with the communication partner device that has determined that the link has not been set by the determination unit. An exchange device configured and communicated. 5. The switching device according to claim 4, wherein said switching device is capable of storing and switching packet data. 6. The switching device according to claim 4, wherein the switching device is a switching device that supports switching of an ISDN (Integrated Services Digital Network). 7. A control method for a switching system having a communication device and a switching device to which the communication device can be connected, wherein the communication device transmits one communication request packet including addresses of a plurality of communication partner devices. The switching device comprises: a receiving step of receiving a communication request packet transmitted in the transmitting step; and starting communication with the communication partner device specified by the communication request packet received in the receiving step. Do
When, at least a portion of the setting state of the link to the communication partner device, and a determination step of determining for each of said plurality of communication partner device, wherein the determination step at least some of the links in the already The communication with the communication partner device determined to be set is performed using the link that has already been set, and a new link is established with the communication partner device that is determined to have no link set in the determination step. A switching system control method for setting and communicating. 8. A receiving step of receiving a communication request packet including addresses of a plurality of communication partner devices, and starting communication with the communication partner device specified by the communication request packet received in the receiving step.
When, at least a portion of the setting state of the link to the communication partner device, and a determination step of determining for each of said plurality of communication partner device, wherein the determination step at least some of the links in the already The communication with the communication partner device determined to be set is performed using the link that has already been set, and a new link is established with the communication partner device that is determined to have no link set in the determination step. And a communication method for controlling the switching device.