JPH05268250A - Call containing system where priority call and nonpriority call coexist - Google Patents

Abstract

PURPOSE:To prevent the deterioration of the using efficiency of a line and to certainly contain the communication of a wide band which is suddenly generated concerning a call containing system where the call having high priority is contained in preference. CONSTITUTION:A nonpriority call communication quality deterioration means 102 makes the communication quality of a nonpriority call which is already connected to its own node to deteriorate by referring to or controlling a connection call management means 101 at the time of setting a priority call so as to ensure the requirement band of the priority call to be set. A nonpriority call path replacing means 105 obtains a by-pass which can ensure the requirement band of the nonpriority call whose communication quality is deteriorated by the nonpriority call communication quality deterioration means 102 by referring-to/controlling the connection call management means 101, a path management means 103 and an empty band management means 104, and replaces the communication route of nonpriority call to the by-pass at the time of finding it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a call accommodating system in which high priority calls are accommodated preferentially.

[0002]

2. Description of the Related Art Generally, in a corporate network that handles surveillance images, control data, voices, etc. in a plant of a factory, etc., communication of media such as voices and control data with a narrow band is usually performed. However, when there is a failure in a plant, for example, broadband image communication for displaying the situation immediately may occur suddenly.

FIG. 22 shows a conventional call accommodating system for accommodating a call generated as described above. In FIG. 22, A,
B, C, and D respectively indicate nodes, and double-sided arrows of thin solid lines between the nodes indicate line bandwidths between the nodes, for example, 1
It is assumed to be 0. Also, a thick solid line one-sided arrow indicates a band of an existing call from one node to another node.

Now, consider communication from node A to node B, for example. As a communication path from A to B, a direct path A → B, a detour path A → C → B, or a detour path A → D → B can be considered. Then, consider a case where a priority call of the band 7 destined to the node B occurs at the node A.

In this case, first, the free band of the direct path A → B is inspected. Then, for example, in the direct path A → B, if there is an existing call in the band 2 and an existing call in the band 3, the priority call in the band 7 cannot be accommodated in the direct path A → B.

Then, next, the alternative paths A → C → B and A
The free band of → D → B is inspected. Here, detour path A
→ C → B, if there is an existing call in band 3 and an existing call in band 4 in paths A → C and an existing call in band 3 in paths C → B, the priority call in band 7 is bypassed. Path A → C → B
Cannot be accommodated. On the other hand, detour path A → D → B
In the case where there is an existing call of band 3 on the path A → D and an existing call of band 2 on the path D → B, the priority call of the band 7 may be accommodated in the detour path A → D → B. it can.

Therefore, finally, the priority call of the band 7 is accommodated in the detour path A → D → B. Here, if there is an existing call of band 1 or more in addition to the existing call of band 3 in the path A → D in the alternative path A → D → B, the priority call of band 7 is the alternative path A → It becomes impossible to accommodate D → B. Therefore, the priority call in the band 7 cannot be accommodated in any path from the node A to the node B, and the priority call is lost.

Therefore, in order to prevent the priority call from being lost in the above-mentioned conventional example, it is necessary to always secure the bandwidth of the priority call on the direct path or the detour path. FIG. 22.
In the example, the line bandwidth of 10 or more must be secured in either the direct path or the detour path between the node A and the node B.

[0009]

However, in the conventional call accommodating system as described above, since the entire reserved line band is hardly used, the line use efficiency is poor and the line cost is low. However, there is a problem in that

On the other hand, if the line band is to be suppressed as much as possible, there is a problem that the priority call is likely to be lost as described above. It is an object of the present invention to prevent deterioration of use efficiency of a line and to reliably accommodate sudden broadband communication.

[0011]

FIG. 1 is a block diagram of the present invention. As a first aspect, the present invention has the following configuration.

First, in the present invention, a call that is always connected at the time of connection request and whose communication quality is guaranteed is accommodated in the network as a priority call, and depending on the state of the network, the call may be temporarily lost or the delay quality is guaranteed. Calls that do not have to be placed are admitted to the network as non-priority calls.

The connection call management means 101 provided in each node for communication individually manages the band of each call already accommodated in the own node. The non-priority call communication quality lowering means 102 provided in each node that performs communication refers to or controls the connection call management means 101 at the time of setting the priority call, and thereby the communication quality of the non-priority call already connected to the own node. , And secure the required priority call bandwidth to be set. This means reduces the service band of the non-priority call already connected to the own node by referring to or controlling the connection call management means, for example.

In addition to the configuration of the first aspect described above, as a second aspect, the present invention can be configured to have the following configuration. First, the path management means 103 manages each route in the network. This means manages, for example, the VCI, the output link, and whether the path is in use or not, for the path to each destination node.

The free band management means 104 manages the free band of each link in the network. The non-priority call path exchanging means 105 provided in each node for communication is a connection call managing means 101, a path managing means 103, and a bandwidth managing means 1.
04 is referred to or controlled to find a detour path capable of ensuring the required bandwidth of the non-priority call whose communication quality is deteriorated by the non-priority call communication quality lowering means 102, and when the detour path is found, the non-priority call is found. The communication path of is replaced with the detour path.

In addition to the configuration of the first or second aspect described above, as a third aspect, the present invention can be configured to have the following configuration. That is, the non-priority call setting means 106 provided in each node that performs communication tells the connection call management means 101 when the non-priority call is set that the service band is the request band of the non-priority call And a detour path having a service bandwidth of 0 is set in advance.

Then, the non-priority call path re-establishment means 105 refers to the detour path preset in the connection call management means 101 when re-establishing the path of the non-priority call.
In addition to the configuration of the first, second or third aspect described above, a fourth aspect
As an aspect of the present invention, the present invention can be configured to have the following configurations.

That is, the above-mentioned non-priority call path switching means 105 sends the route change instruction data to the original direct path of the non-priority call, and receives the route change instruction data from each node on the original direct path. Non-priority call path switching means 1
05 sets the service bandwidth of the direct path registered in the connection call management means 101 to 0. After that, the non-priority call path replacement means 105 sends out the route change setting data on the detour path of the non-priority call, and the non-priority call path replacement means 105 of each node on the detour path receiving the route change setting data, The service band of the detour path registered in the connection call management means 101 is set to the request band of the non-priority call.

In addition to the configuration of the first, second, third or fourth aspect described above, as a fifth aspect, the present invention can be configured to have the following configuration. That is, the non-priority continuous call arrival compensation means 107 provided in each node for communication is
When switching the path of a non-priority call, calculate the delay time from the calling node to the destination node of the non-priority call before switching
The timing to start sending the communication data of the non-priority call to the detour path is delayed by the delay time.

In addition to the above first, second, third, fourth or fifth aspect, as a sixth aspect, the present invention can be configured to have the following configurations. That is, after the path of the non-priority call is changed, the non-priority call communication quality lowering means 10 is set at the time of setting a new priority call on the bypass path of the change destination.
2 reduces the communication quality of the non-priority call that has been switched to the detour path before the non-priority call originally set on the detour path.

In addition to the configuration of the first, second, third, fourth, fifth or sixth aspect described above, as a seventh aspect, the present invention can be configured to have the following configurations. In other words, the non-priority call re-establishment means 108 provided in each node that communicates, after re-establishing the path of the non-priority call, re-establishes the non-priority call to the original direct path, and reestablishes the non-preferred call on the original direct path. Attempts to secure the required bandwidth for priority calls.

Further, in addition to the constitution of the first, second, third, fourth, fifth or sixth aspect, the present invention is an eighth aspect in which the seventh aspect is further specified. It can be configured to have the following configurations.

That is, the non-prioritized call re-establishing means 108 provided in each node that performs communication is such that the communication quality of the non-prioritized call whose path has been reestablished is changed by the non-prioritized call communication quality lowering means 102 to the detour path of the re-established destination. After being lowered, the service bandwidth of the non-priority call on the detour path is compared with the free bandwidth of the original direct path of the non-priority call, and if the free bandwidth is larger, the connection call management means 1
01, the path management means 103, and the bandwidth management means 104, the communication path of the non-priority call is set so that the service bandwidth of the non-priority call becomes equal to or less than the free bandwidth of the original direct path. Switch to the direct pass again.

[0024]

In the first aspect of the present invention, when setting the priority call,
Since the communication quality of the non-priority call that has already been connected is reduced and the delay of the non-priority call in the network is increased, the required bandwidth of the priority call is secured.

In the second aspect of the present invention, for a non-priority call whose communication quality has been reduced by the non-priority call communication quality lowering means 102, the communication path of the non-priority call is switched to a detour path if possible. As a result, the communication quality of non-priority calls is improved.

In the third aspect of the present invention, when a non-priority call is set, a direct path whose service band is equal to the request band of the non-priority call is set in the connection call management means 101 as a communication route of the non-priority call. At the same time, the detour path whose service bandwidth is 0 is set in advance. Then, when the path of the non-priority call is switched, the detour path preset in the connection call management means 101 is referred to. As a result, the replacement of the path is performed at high speed.

In the fourth aspect of the present invention, information relating to path re-establishment of non-priority calls can be efficiently transmitted and received between nodes by using two data, route change instruction data and route change setting data. it can.

In the fifth aspect of the present invention, when the path of the non-prioritized call is re-established, the timing at which the communication data of the non-prioritized call is started to be sent to the bypass path is the originator node of the non-prioritized call before the re-establishment. From the destination node to the destination node. As a result, the continuous arrival of the communication data of the non-priority call that is the target of the replacement at the destination node is compensated.

In the sixth aspect of the present invention, after the path of the non-priority call is re-established, when the new priority call is set on the detour path of the re-establishment destination, the non-priority call set from the beginning on the detour path. The communication quality of the non-priority call that is switched to the alternative path earlier is degraded. As a result, the communication quality of the non-priority call originally set on the detour path is guaranteed as much as possible.

In the seventh aspect of the present invention, after the path of the non-priority call is reestablished, the non-priority call is reestablished to the original direct path and the required bandwidth of the non-priority call is secured on the original direct path. Will be attempted. As a result, the communication quality of non-priority calls is improved.

According to an eighth aspect of the present invention, in the sixth aspect described above, after the communication quality of the non-priority call whose path has been changed is reduced on the bypass path of the change destination, the seventh aspect An attempt is made to reroute the non-priority call back to its original direct path in the same manner as in the embodiment. In this case, the service bandwidth of the non-priority call on the detour path is compared with the free bandwidth of the original direct path of the non-priority call, and if the free bandwidth is larger, the service bandwidth of the non-priority call is determined. The original direct path is replaced so that it is less than or equal to the free band of the original direct path. As a result, the communication quality of the non-priority call is appropriately improved within a possible range.

[0032]

Embodiments of the present invention will now be described in detail with reference to the drawings. Configuration of Embodiment FIG. 2 is a diagram showing an example of a network model used in an embodiment of the present invention. In this example, for ease of understanding, the three nodes A, B, and C are the link ab and the link b.
Models connected to each other by physical transmission lines 201 which are distinguished as a, link ac, link ca, link bc, link cb, and the like are shown. The transmission capacity of each link is, for example, 10 (the unit is, for example, megabit / second).

In the above network, 1 to
A virtual circuit (VC) 202, which is a logical path and is identified by a virtual channel identifier (VCI) such as 11, is set. Then, the communication between the respective nodes is performed using one VC identified by any one of the above VCIs.

Here, for example, VCIs 1 to 4 are links ab
Direct path between nodes A and B set on or above ba,
VCIs 7 to 9 are direct paths between nodes A and C set on the link ac or ca, and VCIs 10 and 11 are links b.
It is a direct path between nodes B and C set on c or cb. The VCIs 5 and 6 are detour paths between the nodes A and B set on the links ac and cb or the links bc and ca.

FIG. 3 is a configuration diagram of a main part of an embodiment of the present invention provided in each node of FIG. Band control unit 30
1 is a VC management table 302 and a connection call management table 3
03 and each content of the free bandwidth management table 304, a call setting process (including a quality reduction process of a non-priority call), a non-priority call switching process, and a communication data continuous arrival compensation process, which will be described later in detail. , Four processes of non-priority call quality improvement processing are executed.

At this time, the band controller 301 controls the buffer read controller 40 of the output link corresponding part of FIG. 4 described later.
5 and delay counter 406. FIG. 4 is a configuration diagram of an output link corresponding unit of the embodiment of the present invention provided in each node of FIG. This corresponding unit is provided for each output link connected to the own node. For example, in the node A of FIG. 2, the above-mentioned corresponding part is provided for each of the output link ab and the output link ac.

In FIG. 4, the priority call buffer 401,
The non-priority call buffer 402 temporarily holds communication data of priority calls and communication data of non-priority calls, respectively. It should be noted that the communication data depends on the communication system of the network, and data of any format such as packet, frame, cell can be adopted.

The route change non-priority call buffer 403
Holds temporarily the communication data of the non-priority call that is the target of the non-priority call switching processing described later. The operation of selectively holding the communication data to be output from the node in any of the above-mentioned three buffers is executed by a distribution circuit (not shown) discriminating the VCI added to each communication data.

The gate 407 is a gate circuit for stopping the output of the route change non-priority call buffer 403 until the delay counter 406 finishes counting the count value set by the band control unit 301 of FIG.

The selector 404 is the priority call buffer 40.
The communication data output from any one of the non-priority call buffer 402 and the route change non-priority call buffer 403 is selectively output to the output link. At this time, the selector 404 sequentially cyclically refers to the contents of the 10 registers in the buffer read control unit 405 at each output timing to the output link, and whether the contents of the referred register indicate a priority call. The output of either the buffer 401 or the buffer 402 (including the buffer 403) is selected depending on whether a non-priority call is indicated.

The contents of the 10 registers of the buffer read controller 405 are set by the bandwidth controller 301 of FIG. The number of registers corresponds to the transmission capacity of each link being 10 in this embodiment. Table Configuration Next, a configuration example of the VC management table 302, the connection call management table 303, and the free bandwidth management table 304 of FIG. 3 will be described.

First, FIG. 10A is a diagram showing an example of the configuration of the VC management table 302 provided in the node A. In this table, for each of the direct path and the detour path to each destination node, the VCI, the output link, and the used / unused flag indicating whether the path is in use or not are set.

FIG. 10B is a diagram showing a configuration example of the connection call management table 303 provided in the node A. In this table, for each terminal accommodated in the own node, the terminal number, the requested bandwidth requested by the terminal at the time of call setup, the service bandwidth actually set by the call setup, and the VCI assigned to the terminal , An output link, and a priority / non-priority flag indicating whether the call is a priority call or a non-priority call. When the terminal requests a non-priority call and a detour path can be set, the service bandwidth, VCI, and
And the output link is set.

FIG. 10C is a diagram showing a configuration example of the free bandwidth management table 304 provided in the node A.
In this table, for each of all links in the network, a link number (identification code), an available band, and the non-priority call buffer 4 of FIG. 4 corresponding to the link.
The average wait time at 02 is set. The value of the free band is updated by the band control unit 301, and the value of the waiting time is detected as a result of the buffer monitoring circuit (not shown) monitoring the state of the non-priority call buffer 402 of each output link. .. Description of Priority Call and Non-Priority Call In the embodiment of the present invention having the above configuration, two priority classes are provided for calls handled by the network. Then, a high-priority broadband call that is always connected when a connection request is made and whose communication quality is guaranteed is accommodated in the network as a priority call. On the other hand, depending on the state of the network, the call may be temporarily lost or delay quality is guaranteed. A low-priority call that may not be performed (the used bandwidth may be forcibly reduced) is accommodated in the network as a non-priority call.

Particularly, when a connection request for a priority call is made, the communication quality of the non-priority call already accommodated is lowered, and specifically, the service assigned to the non-priority call is By reducing the bandwidth and increasing the intra-network delay, control is performed to increase the connection completion rate of request priority calls.

Next, in the above control, for a non-priority call whose communication quality has deteriorated, if there is a free band in the detour path that can guarantee the original communication quality, the non-priority call is switched to the detour path. As a result, the quality of the call of the non-priority class whose communication quality is temporarily reduced can be guaranteed again.

Further, when the non-priority call switching process is performed, a process of compensating the continuity when each communication data of the non-priority call arrives at the destination node is also performed. In addition, on the detour path, when a non-priority call is further degraded in communication quality by another priority call, control is performed to try to return the non-priority call to the original path.

Specific operations of the embodiment of the present invention having the above-mentioned functions will be sequentially described. Initial State Now, as an initial state, for example, one terminal connected to the node A is communicating with another terminal connected to the node B based on a non-priority call.

FIG. 10 is a diagram showing each state of the VC management table 302, the connection call management table 303, and the free bandwidth management table 304 of FIG. 3 provided in the node A in the above case.

First, the VC management table 30 shown in FIG.
2, as shown in FIG. 2, a virtual circuit 202 having each VCI of VC1 to VC4 is set on the output link ab as a direct path to the node B, and an output link as a bypass path to the node B is set. Each virtual circuit 202 having each VCI of VC5 and VC6 is set on ac and the relay link cb. Further, as a direct path addressed to the node C, the virtual circuit 202 having each VCI of VC7 to VC9 is set on the output link ac.

The direct path having the VCI of VC1 and the bypass path having the VCI of VC5 are used by one terminal connected to the node A, and each used / unused flag is set to "in use". Has been done.

Next, the connection call management table 3 of FIG.
03 indicates that the terminal number of one terminal connected to the node A that is currently communicating is 1, the requested bandwidth requested by the terminal at the time of call setup is 3, and VC1
The service band actually set to the direct path having the VCI of 3 is 3, the output link of the direct path is the link ab, and the priority / non-priority flag is “non-priority”, that is, It is set that the call requested by the terminal is a non-priority call.

Further, as a feature relating to the present invention, a detour path having a VCI of VC5 with a service band of 0 is also set for a non-priority call requested by the terminal. This will be described later.

Further, in the free bandwidth management table 304 of FIG. 10C, for each of all links in the network, the link number, the free bandwidth, and the non-priority call buffer 402 corresponding to the link (see FIG. 4). The average waiting time in () is set. As described above, the transmission capacity of each link is 10 each. And the output link ab
In the above, since the call with the service band = 3 is placed as described above, the free band is 7. The value notified from another node is set as the free bandwidth of the other link. For example, no call is placed on the links ac, ba, bc, ca, etc., and the entire band is free.

FIG. 11 shows each output in the node A when one terminal connected to the node A is communicating with another terminal connected to the node B based on the non-priority call as described above. FIG. 6 is a diagram showing a state of data set in a register of a buffer read control unit 405 of FIG. 4 in a link corresponding unit.

First, FIG. 11A is a diagram showing the state of the register of the buffer read control unit 405 of the output link corresponding unit of the output link ab. The number 10 of the registers corresponds to the transmission capacity 10 of the output link, and the selector 404 of FIG. 4 sequentially cyclically refers to the contents of the 10 registers at each output timing to the output link, and refers to the contents. The output of either the buffer 401 or the buffer 402 (including the buffer 403) is selected according to the contents of the registered register.

Therefore, if the service band of the non-priority call having the VCI of VC1 set in the connection call management table 303 of FIG. 10 (b) is 3, as shown in FIG. 11 (a), Identification data indicating a non-priority call is set in any three of the ten registers. As a result, the selector 404 in FIG. 4 of the output link corresponding part of the output link ab
Outputs the communication data of the non-priority call input to the non-priority call buffer 402 to the output link ab at a rate of 3 out of 10 timings. On the other hand, NUL
At the timing when the register in which (invalid data) is set is referenced, the selector 404 does not select the output of any buffer. Then, the number of registers in which NUL is set is determined by the free bandwidth management table 30 in FIG.
This corresponds to the free band set to 4.

FIG. 11B is a diagram showing the state of the register of the buffer read control unit 405 of the output link corresponding unit of the output link ac. Now, as can be read from the free bandwidth management table 304 in FIG. 10C, the output link ac
No call is set up in and the available bandwidth is 10. Therefore, as shown in FIG. 11B, NUL is set in all 10 registers. As a result, the selector 4
04 does not select the output of any buffer at all timings. Non-Priority Call Setting Process Under the above-mentioned initial state, a process will be described in the case where a connection request for a non-priority call destined for the node B having a requested bandwidth of 2 is newly generated from the terminal with the terminal number 2 in the node A.

FIG. 5 is an operation flowchart of the non-priority call setting process realized as a program process executed by the band control unit 301 of FIG. Hereinafter, description will be given with reference to FIG.

First, in step S501, the VC management table 302 is searched for each unused VCI of the direct path and the detour path corresponding to the requested non-priority call. An unused VCI is a V whose used / unused flag indicates "unused".
It can be detected as CI. Then, the used / unused flag corresponding to each searched VCI is changed to “in use”. For example, in the initial state of FIGS. 10 and 11, the direct path having the VCI of VC2 and the VC of VC6 are used.
The detour path having I is searched, and the VC management table 30 is searched.
The state of 2 changes from the state of FIG. 10 (a) to the state of FIG. 12 (a).

Next, in step S502, the available bandwidth of the output link of the direct path of the requested non-priority call is read from the available bandwidth management table 304. The output link of the direct path is read from the VC management table 302. For example, in the initial state of FIG. 10 (c) described above, the output link a of the direct path of the requested non-priority call
The free band 7 of b is read out.

Next, in step S503, it is determined whether the requested bandwidth of the requested non-priority call is larger than the free bandwidth. In the above example, the requested bandwidth of the requested non-priority call is 2 and the available bandwidth is 7, so this determination is NO.

If the determination in step S503 is no,
Step S504 is executed. In step S504, the direct path of the requested non-priority call is set as (service band = request band) in the connection call management table 303. In the above example, as shown in FIG. 12 (b), terminal number = 2, requested bandwidth = 2, service bandwidth =
2, VCI = VC2, output link = ab, priority / non-priority flag = “non-priority”.

At the next step S505, (service band = 0) in the connection call management table 303,
A detour path for the requested non-priority call is established. In the above example, as shown in FIG. 12 (b), the service bandwidth =
0, VCI = VC6, and output link ac information are set. As described above, in the embodiment of the present invention, when setting up a non-priority call, in addition to the direct path, the alternative path is set as
The feature is that it is reserved as 0. As a result, it becomes possible to perform the path replacement processing described later at high speed.

In the next step S506, the value of the free band corresponding to the output link of the direct path of the requested non-priority call is updated in the free band management table 304.
In the above example, the service bandwidth = 2 for the requested non-priority call.
Is allocated, the available bandwidth of the output link ab is
The value 7 in FIG. 10 (c) is updated to the value 5 in FIG. 12 (c).

In the next step S507, the state of the register of the buffer read control unit 405 corresponding to the output link of the direct path of the requested non-priority call is changed. In the above example, the VC of VC2 is newly added to the output link ab.
Since the non-priority call having I is set, the state of the register of the buffer read control unit 405 corresponding to the link is changed from the state of FIG. 11A to the state of FIG.
The state of the register of the buffer read control unit 405 corresponding to the output link ac shown in FIG. 11B does not change.

Finally, in step S508, the fact that the requested non-priority call has been set up at node A is notified to other nodes as call setting information along each of the direct path and detour path of the non-priority call. To be done. This allows
The bandwidth control unit 301 of the other node uses the VC management table 3
02, the contents of the connection call management table 303 and the free bandwidth management table 304, and the states of the registers of the buffer read control unit 405 in the output link corresponding unit of each output link are updated. As a result, the content of each table in each node and the state of the register of the buffer read control unit 405 are updated in synchronization.

On the other hand, if it is determined in step S503 described above that the requested bandwidth of the requested non-priority call is larger than the available bandwidth, step S509 is executed. In step S509, the above-described step S501 is performed.
The state of the used / unused flag set in step 1 is returned to the original state.

Further, in the next step S510, the subscriber (terminal) is notified that the connection of the requested non-priority call has failed. Priority Call Setting Process Including Quality Deterioration Process of Non-Priority Call Next, under the conditions of FIGS. 12 and 13, in the node A, a priority call to the node B newly requested from the terminal having the terminal number 3 is 7 The process when the connection request is generated will be described.

FIG. 6 is an operation flowchart of priority call setting processing including quality reduction processing for non-priority calls, which is realized as program processing executed by the bandwidth control unit 301 of FIG. Hereinafter, description will be given with reference to FIG.

First, in step S601, the VC management table 302 is searched for an unused VCI of the direct path corresponding to the requested priority call. The detour path is not searched. Then, the used / unused flag corresponding to the retrieved VCI is changed to “in use”. For example, in the state of FIG. 12 described above, a direct path having the VCI of VC3 is searched, and the state of the VC management table 302 changes from the state of FIG. 12 (a) to the state of FIG. 14 (a).

Next, in step S602, (service band = request band) in the connection call management table 303.
, The direct path of the requested priority call is set. In the above example, as shown in FIG. 14 (b), the terminal number =
3, required bandwidth = 7, service bandwidth = 7, VCI = VC
3, output link = ab, priority / non-priority flag = “priority”
Each information of is set. In this state, the pieces of information corresponding to the terminal numbers 1 and 2 have not changed as shown in FIG. 14B, but remain as shown in FIG. 12B.

Next, in step S603, the available bandwidth of the output link of the direct path of the requested priority call is read from the available bandwidth management table 304. The output link of the direct path is read from the VC management table 302. For example, in the state shown in FIG. 12C, the free band 5 of the output link ab of the direct path of the requested priority call is read.

Next, in step S604, it is determined whether the requested bandwidth of the requested priority call is larger than the free bandwidth. In the above example, the requested bandwidth of the requested priority call is 7 and the free bandwidth is 5, so this determination is YES.

If the determination in step S604 is yes, step S605 is executed. In step S605, the value of the service band of each non-priority call set on the output link of the direct path of the requested priority call in the connection call management table 303 is determined according to the ratio of the request band of each non-priority call. Then, the free bandwidth of the output link is forcibly reduced so that it becomes zero. In the above example, the service band of each non-priority call on the output link ab corresponding to the terminal numbers 1 and 2 is changed from the values 3 and 2 in FIG.
It is forcibly reduced to the values 2 and 1 in 4 (b).

In the next step S606, the value of the free band corresponding to the output link of the direct path of the requested priority call is updated to 0 in the free band management table 304. In the above example, the free bandwidth of the output link ab is as shown in FIG.
The value 5 in 2 (c) is updated to the value 0 in FIG. 14 (c).

In the next step S607, the fact that the service band of the non-priority call has been changed is notified to other nodes along the direct path of the non-priority call. As a result, the bandwidth control unit 301 of the other node is connected to the connection call management table 3
03, the contents of the free bandwidth management table 304, and the state of the register of the buffer read control unit 405 in the output link corresponding unit of the output link are updated.

In the next step S609, the state of the register of the buffer read control unit 405 corresponding to the output link of the direct path of the requested priority call is changed. In the above example, the VCI of VC3 is newly added to the output link ab.
A priority call with a VC is set, and each VC of VC1 and VC2
Since the service band of each non-priority call having I has been changed, the buffer read control unit 40 corresponding to the link is changed.
The state of the register of 5 is changed from the state of FIG. 13 to the state of FIG. The state of the register of the buffer read control unit 405 corresponding to the output link ac shown in FIG. 11B does not change.

As can be seen by comparing FIGS. 13 and 15, the setting of the priority call reduces the selection ratio of the output of the non-priority call buffer 402 in the selector 404.
As a result, the delay amount in the non-priority call buffer 402 in FIG. 4 increases, and the delay quality of the non-priority call decreases. on the other hand,
It can be seen that the output of the priority call buffer 401 is selected by the selector 404 at a rate according to the requested bandwidth.

In the next step S610, the fact that the requested priority call has been set up in node A is notified to other nodes as call setting information along the direct path of the priority call. As a result, the bandwidth control unit 301 of another node
Is a VC management table 302 and a connection call management table 30.
3, the contents of the free bandwidth management table 304, and the state of the register of the buffer read control unit 405 in the output link corresponding unit of the output link are updated.

On the other hand, when it is determined in step S604 described above that the requested bandwidth of the requested priority call is not larger than the available bandwidth, the available bandwidth of the output link still has a margin and the connection call management table Since it is not necessary to change the service band of the non-priority call in 303,
In step S608, only the processing of updating the value of the free band corresponding to the output link of the direct path of the requested priority call in the free band management table 304 is executed.
After that, the processes of steps S609 and S610 described above are executed.

By the above processing, the service band of the same band as the requested band can be preferentially allocated to the priority call while lowering the quality (delay quality) of the non-priority call as necessary. Non-priority Call Relocation Process Next, a process for reassigning a non-priority call whose service band has been reduced by the above-mentioned priority call setting process to a bypass path will be described.

FIG. 7 is an operation flowchart of the non-priority call reassignment process realized as a program process executed by the band control unit 301 of FIG. Hereinafter, description will be given with reference to FIG. 7.

First, in step S701, the VCI of the detour path of the non-priority call with the service band reduced is detected from the connection call management table 303. When there are a plurality of non-priority calls with reduced service bandwidths, for example, non-priority calls with smaller requested bandwidths are selected in order. In the state of FIG. 14B, first, VC6 is detected as the VCI of the bypass path of the non-priority call corresponding to the terminal number 2. Note that similar processing is executed for a non-priority call corresponding to the terminal number 1 as described later, but in the following description, the non-priority call corresponding to the terminal number 2 will be described as an example.

Next, in step S702, the VC management table 302 is searched for the output link and the relay link set corresponding to the VCI of the bypass path.
In the above example, the output link ac and the relay link cb corresponding to the VCI of VC6 are detected from the VC management table 302 of FIG. 14 (a).

Next, in step S703, each free band of the output link and relay link detected in step S702 is read from the free band management table 304. In the above example, from the free bandwidth management table 304 of FIG. 14C, the free bandwidth 10 corresponding to the output link ac
Then, the free band 7 corresponding to the relay link cb is read.

Next, in step S704, it is determined whether or not all the empty bands read out as described above are equal to or more than the requested band of the non-priority call to be replaced. The requested bandwidth of the non-priority call is the connection call management table 3
It is read from 03.

If the determination in step S704 is NO, it is determined in step S705 whether or not another detour path is set in the connection call management table 303 for the non-priority call to be reestablished. Is yes
If so, each processing of steps S701 to S704 described above is repeated. If the determination in step S705 is no, the path replacement is not performed (step S7).
06).

When the determination in step S704 is YES, it means that the non-priority call can be switched to the detour path. In this case, first, step S707.
At, in the connection call management table 303, the request band of the non-priority call to be reestablished is set in the service band corresponding to the VCI of the bypass path. The service bandwidth of the original direct path is set to 0. In the above example, the service band of the detour path having the VCI of VC6 of the non-priority call corresponding to the terminal number 2 is set to 2, and the service band of the original direct path having the VCI of VC2 is set to 0. As a result, the state of the connection call management table 303 changes from the state of FIG. 14 (b) to the state of FIG. 16 (b).

In the next step S708, the state of the register of each buffer read control unit 405 (FIG. 4) corresponding to each output link of the original direct path and the new detour path is changed. In the above example, the information of the non-priority call having the VCI of VC2 on the output link ab of the direct path is replaced with NUL, and the VC on the output link ac of the detour path.
Two pieces of non-priority call information having a VCI of 6 (corresponding to a service band value of 2) are added. As a result, the states of the registers are as shown in FIG. 15 (output link ab) and FIG.
(b) From the state of (output link ac),
The status is changed to (b).

Next, in step S709, the VCI of the original direct path and the value 0 of the service band are set in the route change instruction data. Then, in step S710, the route change instruction data is notified to other nodes along the original direct path. As a result, the bandwidth control unit 30 of another node
1 updates the contents of the connection call management table 303 and the free bandwidth management table 304, and the state of the register of the buffer read control unit 405 in the output link corresponding unit of the output link. The format of the route change instruction data is shown in FIG. In the above example, the route change instruction data in which VCI = VC2 and service band = 0 is set is transmitted.

Further, in step S711, the VCI of the detour path and the value of the service band are set in the route change setting data. Then, in step S712, the route change setting data is notified to other nodes along the detour path. As a result, the bandwidth control unit 301 of the other node causes the connection call management table 303 and the free bandwidth management table 3
The contents of 04 and the state of the register of the buffer read control unit 405 in the output link corresponding unit of the output link are updated. The format of the route change setting data is shown in FIG. In the above example, VCI = VC6, service band = 2
The route change setting data for which is set is transmitted.

Finally, in step S713, the value of the free band corresponding to the output link of the original direct path and the value of the free band corresponding to the output link of the new bypass path are updated in the free band management table 304. It In the above example, the available bandwidth of the output link ab of the direct path is increased by the service bandwidth 1 reduced by the replacement, and the available bandwidths of the output link ac and the relay link cb of the bypass path are increased by the replacement. It is reduced by the amount of band 2. As a result, the free bandwidth management table 304
The state of FIG. 14 changes from the state of FIG. 14 (c) to the state of FIG. 16 (c).

By the above operation, the non-priority call corresponding to the terminal number 2 is switched from the original direct path having the VCI of VC2 to the detour path having the VCI of VC6. Further, the same operation as described above is tried for the non-priority call corresponding to the terminal number 1. As a result, the non-priority call is
From the original direct path with VCI of VC1 to VC of VC5
It is replaced with a detour path having I.

In this case, the VC management table 302, the connection call management table 303, and the free bandwidth management table 30
The states of 4 change from the states of FIGS. 16 (a), (b), and (c) to the states of FIGS. 18 (a), (b), and (c), and the direct communication Each buffer read control unit 405 corresponding to the output link ab of the path and the output link ac of the detour path
The state of the register of FIG. 17 changes from each state of FIGS. 17A and 17B to each state of FIGS. 19A and 19B. Consecutive arrival compensation processing of communication data When the non-priority call whose service bandwidth is reduced by the priority call setting processing is switched to the alternative path by the above-mentioned non-priority call replacement processing, the following problems may occur. There is.

That is, the buffer waiting time in the non-priority call buffer 402 of FIG. 4 corresponding to the output link of the original direct path is longer than the buffer waiting time in the non-priority call buffer 402 corresponding to the output link of the detour path. In this case, when the communication data targeted for relocation, which remains in the non-priority call buffer 402 corresponding to the output link of the original direct path immediately before the relocation processing, is transmitted to the destination node via that direct path, There is a possibility that the communication data may arrive at the destination node later than the communication data targeted for the replacement, which has been transmitted via the bypass path immediately after the replacement process.

That is, there is a possibility that the communication data transmitted first may arrive at the destination node later than the communication data transmitted later, and the continuity of the communication data may not be maintained.

For example, as shown by the change from FIG. 14 to FIG. 16, setting the priority call of the terminal number 3 reduces the service band of the non-priority calls of the terminal numbers 1 and 2,
After that, when the non-priority call with the terminal number 2 is switched to the detour path, the waiting time in the non-priority call buffer 402 of the output link ab corresponding to the original direct path is as shown in FIG. 16 (c). 90 μsec. On the other hand, the non-priority call buffer 4 of the output link ac corresponding to the bypass path
The waiting time at 02 is 20 as shown in Fig. 16 (c).
μsec. In such a case, the above-mentioned problem may occur in the communication data of the non-priority call of the terminal number 2.

In order to prevent such a situation, in the embodiment of the present invention, the bandwidth control unit 301 of FIG. 3 controls the route change non-priority call buffer 403 and the delay counter 406 of FIG. The process of compensating for successive arrivals of is executed.

First, the band control unit 301 of FIG. 3 turns off the gate 407 of FIG. 4 corresponding to the output link of the detour path so that the output of the route change non-priority call buffer 403 is not output to the selector 404. ..

Next, the distribution circuit (not shown) discriminates the VCI added to the output communication data, and if the VCI is the VCI of the detour path, the communication data is output as shown in FIG. The route change is held in the non-priority call buffer 403. The VCI is the detour path V
Whether it is CI or not can be determined by referring to the VC management table 302.

After that, the band controller 301 of FIG.
The program processing shown in the operation flow chart is executed. Hereinafter, description will be given with reference to FIG. First, in step S801, the VC management table 302 is searched for the output link set for the VCI of the original direct path for the non-priority call that is the target of the replacement. For example, in the example of the change from FIG. 14 to FIG.
The output link ab corresponding to the VCI of VC2 is detected from the VC management table 302 of (a).

Next, in step S802, the waiting time in the non-priority call buffer 402 corresponding to the detected output link is read from the free bandwidth management table 304. If the direct path passes through multiple nodes and there are multiple output links that make up the direct path,
The total latency in the non-priority call buffer 402 for each output link is calculated. For example, FIGS. 14 to 16
14C, the free bandwidth management table 3 in FIG.
From 04, waiting time 100μ corresponding to the output link ab
sec is read.

Succeedingly, in a step S803, the value of the waiting time is set in the delay counter 406 of FIG. 4 corresponding to the output link of the bypass path. For example, in the example of the change from FIG. 14 to FIG. 16, the value of the waiting time of 100 μsec is
Delay counter 40 corresponding to the output link ac of the bypass path
Set to 6.

Thereafter, the process of step S804 for counting down the counter value of the delay counter 406 is repeated until it is determined in step S805 that the counter value has become zero.

If it is determined in step S805 that the counter value has reached 0, the gate 407 is turned on in step S806. As a result, the communication data can be read from the route change non-priority call buffer 403.

Thereafter, in step S806, the selector 404 outputs the output of the route change non-priority call buffer 403 to the output link according to the contents of the buffer read control unit 405. Here, the selector 404, when the VCI for the bypass path is set in the register of the buffer read control unit 405 which is currently being referred to, the gate 407.
Select the output of. Whether the VCI set in the register is the detour path VCI is determined by the VC management table 3
It can be determined by referring to 02. For example, in FIG.
In the example of (b), the gate 407 is selected at the timing when the register in which the VCI of VC6 is set is referred to.

As described above, at the time of non-priority call switching processing, forcibly delaying the start of the output of the communication data of the non-priority call targeted for switching in the output link corresponding part of the output link of the alternative path. This makes it possible to compensate for the continuous arrival of communication data of the non-priority call that is the target of the replacement. Quality improvement processing the last of the non-priority call, even if the path of the non-priority call has been repositioned by detouring process of the non-priority call described above, the connection of another priority call for the replacement destination of the detour path as the direct path When a request occurs, the service bandwidth of the non-priority call may be reduced again by the priority call setting process of FIG. 6 described above.

In this case, first, after the communication quality of the non-priority call whose path has been switched has been lowered, if further necessary, the communication of the non-priority call set from the beginning to the bypass path of the switching destination is started from the beginning. Quality is reduced. As a result, it is possible to guarantee the quality of the non-priority call set to the detour path of the replacement destination from the beginning as much as possible.

Further, when the communication quality of the non-priority call whose path has been switched is deteriorated, the communication quality that tries to re-route the non-priority call to the original direct path of the non-priority call is tried. Improvement processing is executed.

FIG. 9 is an operational flowchart of the quality improvement processing of the non-priority call realized as the program processing executed by the bandwidth control unit 301 of FIG. Hereinafter, description will be given with reference to FIG.

First, in step S901, the VCI of the original direct path of the non-priority call whose service band has already been reduced on the detour path of the replacement destination is the connection call management table 30.
3 is detected. When there are a plurality of such non-priority calls, for example, non-priority calls with the smallest requested bandwidth are selected in order.

Next, in step S902, the VC management table 302 is searched for the output link set corresponding to the VCI of the original direct path. When a direct path passes through a plurality of nodes and there are a plurality of output links that form the direct path, all output links are searched.

Next, in step S903, the free band of the output link detected in step S902 is read from the free band management table 304. Next, in step S904, it is determined whether or not all the empty bands read out as described above are equal to or more than the service band on the detour path of the non-priority call to be replaced. The service band of the non-priority call is the connection call management table 303.
Read from.

If the determination in step S904 is no, the path reassignment is not performed (step S90).
5). If the determination in step S904 is YES,
This is a case where it is possible to switch the non-priority call to the original direct path.

In this case, further, in step S906, all the empty bands read as described above are
It is determined whether or not the bandwidth is equal to or higher than the required bandwidth of the non-priority call to be reestablished. The requested bandwidth of the non-priority call is read from the connection call management table 303.

If the determination in step S906 is yes, in step S907, the connection call management table 3
The request band of the non-priority call to be switched is set to the service band corresponding to the VCI of the original direct path 03.

On the other hand, if the determination in step S906 is NO, in step S908, the service bandwidth corresponding to the VCI of the original direct path in the connection call management table 303 is set to the free bandwidth obtained in step S903. To be done.

Next, in step S909, the service bandwidth of the bypass path is set to zero. In the next step S910,
The state of the register of each buffer read control unit 405 (FIG. 4) corresponding to each output link of the original direct path and detour path is changed.

Next, in step S911, the VCI of the detour path and the value 0 of the service band are set in the route change instruction data. Then, in step S912, the route change instruction data is notified to other nodes along the detour path. As a result, the bandwidth control unit 301 of the other node causes the connection call management table 303 and the free bandwidth management table 3
The contents of 04 and the state of the register of the buffer read control unit 405 in the output link corresponding unit of the output link are updated. The format of the route change instruction data is the same as that shown in FIG.

Further, in step S913, the values of the VCI and service band of the original direct path are set in the route change setting data. Then, in step S914, the route change setting data is notified to other nodes along the original direct path. As a result, the bandwidth control unit 301 of another node
Updates the contents of the connection call management table 303 and the free bandwidth management table 304, and the state of the register of the buffer read control unit 405 in the output link corresponding unit of the output link. The format of the route change setting data is the same as that shown in FIG.

Finally, in step S915, the value of the free band corresponding to the output link of the original direct path and the value of the free band corresponding to the output link of the bypass path are updated in the free band management table 304. Other Embodiments In the above-described embodiments, the process of improving the communication quality that attempts to re-establish the non-priority call whose path has already been re-established to the original direct path of the non-priority call is performed by the re-established bypass path. The above is executed at the timing when the service band of the non-priority call is reduced, but the present invention is not limited to that configuration, and is executed unconditionally after an appropriate time after the path replacement, for example. Such a configuration may be adopted.

Further, in the above embodiment, for each node,
VC management table 302 and free bandwidth management table 30
4 is provided, the present invention is not limited to the configuration, and these tables are provided only in a specific node, and each node makes an inquiry to the node and refers to these tables. May be

[0124]

According to the first aspect of the present invention, at the time of setting a priority call, the communication quality of a non-priority call that has already been connected is reduced and the intra-network delay of the non-priority call is increased. Thus, it becomes possible to ensure the required bandwidth for the priority call.

According to the second aspect of the present invention, the non-priority call whose communication quality is lowered by the non-priority call communication quality lowering means 102 can be switched to the alternative path, and the communication quality of the non-priority call is improved. It becomes possible.

According to the third aspect of the present invention, it is possible to change the path of a non-priority call at high speed. According to the fourth aspect of the present invention, it is possible to efficiently send and receive information regarding path re-establishment of non-priority calls between two nodes by using two data, route change instruction data and route change setting data. Becomes

According to the fifth aspect of the present invention, it is possible to compensate for the continuous arrival of the communication data of the non-priority call that is the target of the replacement at the destination node. According to the sixth aspect of the present invention, it is possible to guarantee the communication quality of a non-priority call set on the detour path from the beginning as much as possible.

According to the seventh aspect of the present invention, it becomes possible to improve the communication quality of the non-priority call after the path of the non-priority call is switched. According to the eighth aspect of the present invention, even after the communication quality of the non-priority call whose path has been changed is reduced on the bypass path of the change-over destination, the communication quality of the non-priority call is maintained. It is possible to improve appropriately within a possible range.

As described above, according to the present invention, it is possible to realize a call accommodating method which is excellent in the use efficiency of the transmission line in the corporate network and the like, and it is possible to reduce the use cost of the leased line.

[Brief description of drawings]

FIG. 1 is a block diagram of the present invention.

FIG. 2 is a diagram showing an example of a network model used in an embodiment of the present invention.

FIG. 3 is a configuration diagram of a main part of an embodiment of the present invention.

FIG. 4 is a configuration diagram of an output link corresponding unit according to the embodiment of this invention.

FIG. 5 is an operation flowchart of non-priority call setting processing.

FIG. 6 is an operation flowchart of priority call setting processing including quality reduction processing for non-priority calls.

FIG. 7 is an operation flowchart of a non-priority call switching process.

FIG. 8 is an operation flowchart of communication data continuous arrival compensation processing.

FIG. 9 is an operation flowchart of quality improvement processing of a non-priority call.

FIG. 10 is a diagram showing a state of each table before a connection request for a non-priority call addressed to a node B is issued from the terminal 2.

FIG. 11 is a diagram showing a state of a buffer read control unit before a connection request for a non-priority call addressed to a node B is issued from the terminal 2.

FIG. 12 is a diagram showing a state of each table after a non-priority call addressed to a node B is set from the terminal 2.

FIG. 13 is a diagram showing a state of the buffer read control unit after a non-priority call addressed to the node B is set up from the terminal 2.

FIG. 14 is a diagram showing a state of each table after a non-priority call addressed to a node B is set from the terminal 3.

FIG. 15 is a diagram showing a state of a buffer read control unit after a non-priority call addressed to a node B is set up from the terminal 3.

16 is a diagram showing a state of each table after a non-priority call destined for the node B is set from the terminal 3 and after the path of the non-priority call of the terminal number 2 is changed. FIG.

FIG. 17 is a diagram showing a state of the buffer read control unit after a non-priority call addressed to the node B is set up from the terminal 3 and after the path of the non-priority call with the terminal number 2 is changed. is there.

FIG. 18 is a diagram showing a state of each table after a non-priority call addressed to the node B is set from the terminal 3 and after the path of the non-priority call of the terminal number 1 is changed.

FIG. 19 is a diagram showing a state of the buffer read control unit after the non-priority call addressed to the node B is set up from the terminal 3 and after the path of the non-priority call with the terminal number 1 is changed. is there.

FIG. 20 is a diagram showing a format of route change instruction data.

FIG. 21 is a diagram showing a format of route change setting data.

FIG. 22 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 101 Connected Call Management Means 102 Non-Priority Call Communication Quality Degradation Means 103 Path Management Means 104 Free Bandwidth Management Means 105 Non-Priority Call Path Replacement Means 106 Non-Priority Call Setting Means 107 Non-Priority Call Continuous Arrival Compensation Means 108 Non-Priority Call Re-establishment Means

Continuation of front page (51) Int.Cl. ⁵ Identification number Reference number in the agency FI Technical indication location 8529-5K H04L 11/20 102 A (72) Inventor Kazuo Sakakawa 1015 Uedotachu, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited In-house (72) Inventor Yoshihiro Watanabe 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited (72) Inventor Toshio Somiya 1015, Kamedotachu, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited

Claims (8)

[Claims] 1. A call, which is always connected when a connection request is made and whose communication quality is guaranteed, is accommodated in the network as a priority call, and depending on the state of the network, call loss may occur temporarily or delay quality may not be guaranteed. A good call is accommodated in the network as a non-priority call, and a connection call management means (101) that individually manages the bandwidth of each call that is already accommodated in the own node in each node that communicates, and at the time of setting the priority call , A non-priority call communication quality that secures a requested bandwidth of a set priority call by lowering the communication quality of the non-priority call already connected to the own node by referring to or controlling the connection call management means (101) Degrading means (10
2) and a call accommodating method in which priority calls and non-priority calls are mixed, characterized in that 2. A path management means (103) for managing each path in the network, a free bandwidth management means (104) for managing a free bandwidth of each link in the network, and a node provided for communication, By referring to or controlling the connection call management means (101), the path management means (103), and the bandwidth management means (104),
A detour path capable of ensuring the required bandwidth of the non-priority call whose communication quality has been reduced by the non-priority call communication quality lowering means (102) is obtained, and when the detour path is found, the detour path is detoured on the communication path of the non-priority call. The call accommodating system according to claim 1, further comprising: a non-priority call path re-establishment means (105) for re-establishing a path. 3. A service band is provided in each node that performs communication, and when a non-priority call is set, the service band is the same as the request band of the non-priority call in the connection call management means (101) as a communication path of the non-priority call. The system further comprises a non-priority call setting means (106) for setting a direct path and preliminarily setting a detour path having a service band of 0, wherein the non-priority call path switching means (105) is a path for the non-priority call. The connection call management means (10
The call accommodating method according to claim 2, wherein the detour path preset in 1) is referred to. 4. The non-priority call path re-establishing means (105), when re-establishing the path of the non-priority call, sends route modification instruction data to the original direct path of the non-priority call, and modifies the route modification instruction data. The non-priority call path exchanging means (105) of each node on the original direct path that has received the message sets the service bandwidth of the direct path registered in the connection call managing means (101) to 0, and thereafter, The non-priority call path re-establishing means (105) sends the route change setting data onto the detour path of the non-priority call, and the non-priority call path re-establishing means (105) of each node on the detour path receiving the route change setting data. ) Sets the service band of the detour path registered in the connection call management means (101) to the request band of the non-priority call, The priority call and the non-priority call according to claim 3, Call receiving method to be mixed. 5. A delay time from a source node to a destination node of the non-priority call before the re-establishment is provided at the time of re-establishing the path of the non-priority call, the delay path being provided to each node for communication, The non-priority call continuous arrival compensating means (107) for delaying the timing of starting the transmission of the communication data of the priority call by the delay time, further comprising: A call accommodating method in which the described priority calls and non-priority calls are mixed. 6. After setting up the path of the non-priority call, when setting up a new priority call on the detour path of the replacement destination,
The non-priority call communication quality lowering means (102) lowers the communication quality of the non-priority call that has been switched to the detour path before the non-priority call originally set on the detour path. The call accommodation system according to claim 2, wherein the priority call and the non-priority call are mixed. 7. A request band of the non-prioritized call provided on each node for communication, after re-establishing the path of the non-priority call, re-establishing the non-priority call to its original direct path, and re-establishing the non-priority call on the original direct path. A call accommodation system in which a priority call and a non-priority call are mixed according to any one of claims 2 to 6, further comprising a non-priority call re-rearranging means (108) for attempting to secure . 8. The communication quality of the non-prioritized call, which is provided in each node that performs communication and whose path has been switched, is reduced by the non-priority call communication quality lowering means (102) on the alternate path of the re-establishment destination. Then, the service bandwidth of the non-priority call on the detour path is compared with the free bandwidth of the original direct path of the non-priority call, and if the free bandwidth is larger, the connection call management means (101) , The path management means (103) and the bandwidth management means (104) are referred to or controlled so that the service bandwidth of the non-priority call is less than or equal to the free bandwidth of the original direct path. 7. The call accommodating system according to claim 6, further comprising a non-priority call re-establishing means (108) for re-establishing a communication path to the original direct path.