JPH0683256B2 - Call exchange method for packet exchange communication - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a call setting method for packet switching communication in a packet switching network having terminals accommodated in a packet switching station by a plurality of physical circuits, and particularly for each physical circuit. It is about load balancing.

[Prior Art] FIG. 2 is a block diagram showing a conventional call setting method for packet switching communication. In the figure, 1 is a calling side terminal and 2 is a calling side terminal in which the terminal 1 is accommodated. Packet switching station,
3 is a calling request packet sent from the terminal 1 to the packet switching station 2, 4 is an inter-station calling request packet sent from the packet switching station 2, and 5 is a called side which receives the calling request packet 4. Packet switching station, 6 is a called terminal accommodated in the packet switching station 5 by three physical lines 7, 8 and 9, and 10 is the called packet switching station 5.
The line information table set in the inside, 11 is the physical line 7
An incoming call packet sent from the terminal 6 to the packet switching station 5 on the physical line 7 and an incoming call packet sent from the called packet switching station 5 to the packet switching station 5 on the physical line 7. An inter-station connection completion packet sent to the exchange 2 and a connection completion packet 15 sent from the packet exchange 2 to the terminal 1.

Next, the operation will be described. First, the terminal 1 on the calling side sends a calling request packet 3 to the exchange 2. Upon receiving it, the packet switching station 2 performs a process of adding an inter-station header to the received call request packet 3, generates an inter-station call request packet 4, and transmits it to the called-side packet exchange station 5. To do. When the packet switching station 5 receives the inter-station call request packet 4, three physical lines to the called-side terminal 6 that is the destination of the inter-station call request packet 4 are received.
Search for 7,8,9. Next, referring to the line information table 10 for each physical line 7, 8 and 9, one physical line whose number of free logical channels (hereinafter referred to as ELCN) is not "0" is set.
A book is selected from the line information table 10 to secure the logical channel. In the example shown in FIG. 2, when the physical line 7 is referred to in sequence, the ELCN of the physical line 7 is not "0", so that the logical channel on the physical line 7 is secured.

Next, the packet switching center 5 on the called side transmits the called packet 11 to the terminal 6 on the called side using the logical channel secured on the physical line 7. Upon receiving this incoming call packet, the terminal 6 generates an incoming call acceptance packet 13 in response to it and returns it to the packet switching center 5. At the packet switching station 5,
An inter-office header is added to the received incoming call acceptance packet to generate an inter-station connection completion packet 14, which is sent to the packet switching station 2 on the calling side. The packet switching station 2 on the calling side deletes the inter-station header from the received inter-station connection completion packet 14,
The connection completion packet 15 is transmitted to the calling terminal 1.
The call is set up by the above procedure.

[Problems to be Solved by the Invention] Since the conventional call setting method of packet switching communication is configured as described above, when a large number of call setting requests are made to the called terminal 6 The problem that calls are concentrated on the younger one of the physical lines 7,8,9 owned by the terminal 6 and the load on each physical line 7,8,9 becomes significantly uneven. There was a point.

The present invention has been made in order to solve the above problems, and when a plurality of physical lines are provided between a called terminal and a packet switching station in which the terminal is accommodated, the It is an object of the present invention to obtain a call setup method for packet switching communication in which the load on each line is almost uniform.

[Means for Solving Problems] A call setup method for packet switching communication according to the present invention is a packet switching station having a plurality of physical lines for each physical line of a terminal accommodated in the packet switching station. Information on the number of logical channels in use (hereinafter referred to as ULCN) and ELCN is stored, and when the call arrives, this ELCN is not zero, and
The physical line with the smallest ULCN is selected.

[Operation] According to the call setting method of the packet switching communication of the present invention, when a new call arrives at a terminal accommodated in the packet switching station by a plurality of physical circuits, each physical circuit in the packet switching station By selecting the physical line that has the least ELCN and the minimum ULCN by referring to the ULCN and ELCN of, the physical line with an empty logical channel is surely selected, and The load on the line can be made uniform.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, 1 is a calling side terminal, 2 is a calling side packet switching station, 3 is a calling request packet, 4 is an inter-station calling request packet, 5 is a called side packet switching station, and 6 is a calling side. Terminals on the call side, 7, 8 and 9 are physical lines, 11 is an incoming call packet, 13 is an incoming call acceptance packet, 14 is an inter-station connection completion packet, and 15 is a connection completion packet. Since these are the same as or equivalent to those of the conventional ones, the detailed description will be omitted.

12 is a new line information table in which the ULCN of each physical line is added to the conventional line information table 10, and 12a, 12b, 12c
3 shows the contents of the line information table 12 after receiving the inter-station call request packet 4, after transmitting the incoming packet 11, or after transmitting the incoming packet 18, respectively.
Further, 16 is a call request packet sent from the terminal 1 to the packet switching station 2, which is different from the call request packet 3, and 17 is from the packet switching station 2 on the calling side in response to the call request packet 16. Inter-station call request packet sent to the called-side packet switching station 5, 18 is a call-in packet sent to the terminal 6 on the physical line 8 in response to this inter-station call request packet, and 20 is this call-in An incoming call acceptance packet sent back from the terminal 6 to the packet exchange station 5 on the physical line 8 in response to the packet 18, and 21 indicates the incoming call acceptance packet 20 from the called side packet exchange station 5 to the originating side. Is an inter-station connection completion packet sent to the packet switching station 2 and 22 is a connection completion packet sent from the packet switching station 2 to the terminal 1 in response to the inter-station connection completion packet.

Next, the operation will be described. First, when the call request packet 3 transmitted by the caller-side terminal 1 is received, the packet switching center 2 adds an inter-station header to the received call request packet 3 to generate an inter-station call request packet 4. , To the packet switching station 5 on the called side. Upon receiving the inter-station call request packet 4, the called-side packet switching station 5 sends three physical lines 7, 8 to the called-side terminal 6 which is the destination of the inter-station call request packet 4. 9 is searched, the line information table 12 is sequentially referred to for each physical line 7, 8 and 9, and the line information table 12
The ELCN is not "0", and the ULCN selects one physical line with the minimum and secures the logical channel. Line information table 12
If the content of the item is in the state indicated by 12a, ELCN is "1" and U
The logical channel on the physical line 7 having the smallest LCN of "3" is secured.

Next, the packet switching center 5 uses the logical channel secured on this physical line 7 to send the incoming call packet to the called terminal 6.
11 is sent and the SBID in the line information table 12
EL of data part corresponding to physical line 7 indicated by = 0
The value of CN is decremented by 1 and the value of ULCN is decremented by 1 to obtain the state indicated by 12b. The terminal 6 which has received the incoming call packet 11 generates an incoming call acceptance packet 13 in response to it and returns it to the packet exchange station 5. The packet exchange station 5 adds an inter-station header to the incoming call acceptance packet 13. And sends it as an inter-station connection completion packet 14 to the packet switching station 2 on the calling side. The calling-side packet switching station 2 deletes the inter-station header from the received inter-station connection completion packet 14 and sends it as a connection completion packet 15 to the calling side terminal 1 to complete the call setting.

After that, when a call is again made from the terminal 1 to the terminal 6,
The call request packet 16 transmitted from the terminal 1 is received by the packet switching station 2, and the packet switching station 2 generates an inter-station call request packet 17 from the call request packet 16 and sends it to the packet switching station 5. . Upon receiving this inter-station call request packet 17, the packet switching station 5 sequentially refers to the line information table 12 for the three physical lines 7, 8 and 9 to the terminal 6. The state of the line information table 12 is as indicated by 12b as described above. The physical line 7 is excluded from the selection because the ELCN of the corresponding SBID = 0 data section is "0", and the remaining two lines are From the physical lines 8 and 9, a logical channel on the physical line 8 corresponding to the data portion SBID = 1 in which the ELCN is “2” and the ULCN is the smallest “4” is secured.

Next, the packet switching center 5 uses the logical channel secured on this physical line 8 to send the incoming call packet to the called terminal 6.
18 is transmitted and the EL of the data section indicated by SBID = 1 corresponding to the physical line 8 in the line information table 12
The value of CN is decremented by 1 and the value of ULCN is decremented by 1 to obtain the state indicated by 12c. The terminal 6 receiving the incoming call packet 18 generates an incoming call acceptance packet 20 in response to the incoming call packet 18,
To the packet exchange station 5, and the incoming call acceptance packet
An inter-station connection completion packet 21 is generated from 20 and sent to the packet switching station 2 on the calling side. The packet switching center 2 on the calling side transmits a connection completion packet 22 generated from the received inter-station connection completion packet 21 to the calling side terminal 1 to complete the call setting.

[Effects of the Invention] As described above, according to the present invention, a packet switching station has information of ULCN and ELCN for each physical line of a terminal accommodated in the packet switching station through a plurality of physical lines. By the way, the ELCN when the call arrives is not zero, and this
Since it is configured to select the physical line with the smallest ULCN, the physical line with the free logical channel is surely selected in the call setup process for the terminal accommodated by multiple physical lines in the packet switching center. In addition, the load on each physical line can be made uniform.

[Brief description of drawings]

FIG. 1 is a block diagram showing a call setting system for packet switching communication according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a call setting system for conventional packet switching communication. 5 is a packet switching station, 6 is a terminal, 7, 8 and 9 are physical lines, 12
Is the line information table. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norihiko Toyota 5-1-1, Ofuna, Kamakura-shi, Kanagawa Mitsubishi Electric Corporation Information Electronics Laboratory (56) Reference Japanese Patent Laid-Open No. 62-57343 (JP, A) Kai 61-69238 (JP, A) JP 62-145946 (JP, A)

Claims (1)

[Claims] 1. A call setup method for packet switching communication in a packet switching network, comprising a terminal accommodated in a packet switching station by a plurality of physical circuits, wherein the packet switching station is provided with each physical circuit of the terminal. Information about the number of logical channels in use and the number of free logical channels is stored, and when a call to the terminal arrives, the packet switching station refers to the information on the number of logical channels in use and the number of free logical channels. , Selecting a physical line in which the free logical channel is not zero and the number of used logical channels is the smallest among the physical lines to the terminal, and the call is made by the terminal using the physical line. A call setup method for packet-switched communication, characterized in that the call is received by the user.