JP3016023B1 - How to reserve network resources - Google Patents

Abstract

Abstract: [PROBLEMS] When there is a surplus of communication resources in another route,
Even if a single path with the requested bandwidth does not exist between the sending and receiving hosts, make the necessary resource reservations. SOLUTION: A notification signaling A is transmitted from a reception host 4 to a transmission host 5, and a request bandwidth X of each router configuring a path between the two is based on a reservation signaling B returned from the transmission host 5 in response to the notification signaling A. Make a reservation. Here, if the reservation is not possible, the upstream node is notified by reservation signaling B, whereby the detour route for the route with the insufficient bandwidth at the upstream node is searched to reserve the bandwidth of the insufficient XY.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reserving network resources, and more particularly to a method for reserving resources for data communication using a plurality of paths provided in parallel between transmitting and receiving hosts. It is.

[0002]

BACKGROUND OF THE INVENTION The Internet is currently undergoing a transformation in order to provide a wider range of quality of service (QoS). Recently, IETF (Internet Engineering T
ask Force), a new resource reservation protocol (RSVP: Resource reservat) for the purpose of diversifying services.
ionprotocol).

The RSVP is a protocol for managing a transmission band of a specific communication channel, that is, a network resource, between routers used in an IP network, and is an OSI reference model, layer 4, ie, TCP / I.
Functions as an upper layer protocol of P. As a result, a communication mode such as multimedia communication that requires data transfer while maintaining a constant transmission rate can be realized on the Internet.

[0004]

According to the RSVP, an upper application of an end host starts a session by reserving resources before actual communication starts. Here, TCP / IP which is the basis of RSVP
Uses a connection-type communication mode in which a single path is connected between the sending and receiving hosts, and the RSVP mounted on the router uses a single path having a required bandwidth as a route connecting the sending and receiving hosts. It is assumed to be searched.

[0005] However, when such a route does not exist when the reservation of the communication resource is requested, there is a problem that the user is simply rejected due to lack of resources. The present invention is intended to solve such a problem, and when there is a surplus of communication resources in other routes, even if a single path having the required bandwidth does not exist between the transmitting and receiving hosts, It is an object of the present invention to provide a network resource reservation method capable of performing resource reservation.

[0006]

In order to achieve the above object, a network resource reservation method according to the present invention comprises:
The first host initiates bandwidth reservation by sending notification signaling including the requested bandwidth to the network to the second host, and the second host responds to the notification signaling in response to the notification signaling received from the network. Each router that transmits reservation signaling indicating reservation of a requested bandwidth notified from the first host by signaling to the network to the first host, and configures a predetermined path connecting the first and second hosts Then, in response to this reservation signaling, it is determined whether or not the own router can reserve a bandwidth for the requested bandwidth, and the result is added to the reservation signaling, and then sequentially transferred to the upstream router on the first host side. It was made. Then, the first host starts the data communication after confirming the success of the reservation of the requested bandwidth by the reservation signaling received from the network, and each router starts the downstream router on the second host side by the received reservation signaling. If a notification indicating that reservation is impossible is received from the path, a search is made for a detour that is parallel to the section where the bandwidth is insufficient in the path, and the bandwidth is reserved by the amount of the insufficient bandwidth using the detour. It was done.

Each of the routers stores the requested bandwidth notified by the notification signaling in response to the reception of the notification signaling, and stores the requested bandwidth by itself in response to the reception of the reservation signaling. It is determined whether or not the requested bandwidth can be reserved by comparing it with the reservable bandwidth. If the reservation is possible, information indicating the reservability is added to the reservation signaling. Information indicating the shortage of the bandwidth obtained from the difference between the bandwidth and the reservable bandwidth of the own router and information indicating that reservation is impossible is added to the reservation signaling and transferred.

[0008] If the first router among the routers notifies that the reservation cannot be made from the second downstream router by the received reservation signaling, the first router is arranged in parallel with the section of the path where the bandwidth is insufficient. Searching for a detour from the own router to the second router, transmitting a new notification signaling including the insufficient bandwidth to the searched detour to the downstream router, and starting a bandwidth reservation; Sends, to the network, new reservation signaling instructing reservation of insufficient bandwidth notified from the first router by the notification signaling in response to the notification signaling received from the first router. It is like that. Then, each router configuring this detour determines whether or not the own router can reserve a bandwidth for the insufficient bandwidth in response to the new reservation signaling, and adds the result to the reservation signaling. The first router sequentially transfers the information to the upstream router on the side of the first router, and after confirming the success of the reservation of the insufficient bandwidth by the received new reservation signaling, transmits the information indicating that the required bandwidth can be reserved for the path. This is added to the reservation signaling and transferred to the upstream router on the first host side.

[0009] In each of the routers constituting the bypass route, if the new router receives the new reservation signaling and notifies the downstream router on the second router side that reservation is impossible, the bandwidth of the bypass route becomes insufficient. A new detour in parallel with the existing section is searched for, and the new detour is used to reserve a bandwidth for the new bandwidth shortage.

In addition, a router bandwidth management server for managing the bandwidth reservation status of each router is provided, and each router sequentially notifies the router bandwidth management server of the bandwidth reservation status of its own router,
In the case where the reservation reservation is notified from the downstream router of the second host by the received reservation signaling, the detour route capable of reserving the bandwidth for the insufficient bandwidth is provided for the section of the path where the bandwidth is insufficient. A request is made to the router bandwidth management server for a search, and based on the obtained detour information, the bandwidth is reserved for the insufficient bandwidth using the detour, and the router bandwidth management server manages the bandwidth by itself. Based on the bandwidth reservation status of each router, a search is made for a detour that can reserve a bandwidth for the insufficient bandwidth, and detour information indicating the obtained detour is returned.

[0011]

Next, the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing a data communication system to which a network resource reservation method according to a first embodiment of the present invention is applied. (A) is a configuration diagram showing the entire system, and (b) is a block showing a router. FIG. FIG.
In (a), a receiving host 4 (first host) and a transmitting host 5 (second host) are connected via a network including routers 1 to 3.

The receiving host 4 is connected to the router 1 via a link 11, and the transmitting host 5 is connected to the router 3 via a link 13. Further, the router 1 is connected to the router 2 via the link 12 and
And the router 3 is connected to the router 3 via the link 15. In the following, a case will be described in which the transmission host 5 that actually transmits data reserves network resources, that is, a bandwidth, necessary for data reception from the reception host 4 that receives data from the transmission host 5.

In this case, similarly to the above-described RSVP, a notification signaling A for notifying the requested bandwidth to the transmission host is transmitted from the reception host 4, and the notification signaling A is used for the router 1 and the router 1 forming a path connecting the reception host 4 and the transmission host 5. Router 2
, And received by the sending host 5. Reservation signaling B for instructing bandwidth reservation is transmitted from the transmission host 5 to the reception host 4, and actual bandwidth reservation is performed in the router 1 and the router 2 based on the reservation signaling B.

Here, the configuration of the router will be described with reference to FIG. The routers 1 to 3 have the same configuration, and the bandwidth reservation signaling processing unit 21 processes various kinds of signaling (messages) exchanged between the adjacent upstream node and downstream node for bandwidth reservation. Bandwidth reservation is performed. Requested bandwidth storage unit 2
In 4, the requested bandwidth notified by the notification signaling A is stored, and in the upstream node storage unit 25, an address indicating the node immediately before the received notification signaling A is transferred is stored.

Hereinafter, based on the transfer direction of the notification signaling A transferred from the receiving host 4 to the transmitting host 5, the receiving host 4 side is referred to as upstream, and the transmitting host 5
Is called the downstream side. For example, in the router 2, the router 1 is an upstream node, and the transmission host 5 is a downstream node.

The reception control unit 22 confirms the bandwidth reservable by the own router. In response to the reservation signaling received by the bandwidth reservation signaling processing unit 21, the main determination unit 23 reserves only the requested bandwidth if the own router can reserve only the requested bandwidth, and detours if the bandwidth is insufficient. Instruct a search for a road. In accordance with an instruction from the main determining unit 23, the detour search unit 26 searches for a detour to a predetermined router based on routing information 27 preset as information indicating a network configuration.

Next, the operation of the first embodiment of the present invention will be described with reference to FIG. 2 in a case where each router can reserve a required reserved bandwidth. FIGS. 2A and 2B are explanatory diagrams showing an example of the operation according to the first embodiment. FIG. 2A is a system configuration diagram, and FIG. 2B is a sequence diagram showing the exchange of signaling. First, from the receiving host 4 to the transmitting host 5
, Notification signaling A including the requested bandwidth X is transmitted (step 31).

The bandwidth reservation signaling processing unit 2 of the router 1
1 communicates this notification signaling A31 over link 11
Is received and notified to the main determination unit 23. Main judgment part 2
3, the request bandwidth X stored in the notification signaling A is stored in the request bandwidth storage unit 24, and the address of the upstream node (the receiving host 4 in this case) that transmitted the notification signaling A to the router 1 is set to the upstream. It is stored in the node storage unit 25.

Thereafter, the notification signaling A31 is transferred from the bandwidth reservation signaling processing section 21 of the router 1 to the router 2 (step 32). In this way,
The notification signaling A is transferred at each router forming a path connecting the receiving host 4 and the transmitting host 5. And
In that case, the required bandwidth and the individual upstream nodes stored in the notification signaling A at each router are stored.

The transmitting host 5 receives the notification signaling A transferred by the router 2 (step 33), determines whether or not data can be transmitted in the requested bandwidth X notified by this, and if transmission is possible, The reservation signaling B for instructing the reservation of the requested bandwidth X is sent to the notification signaling A.
(Step 34). The bandwidth reservation signaling processing section 21 of the router 2 receives the reservation signaling B and notifies the main determination section 23 of the reception.

In response to this, the main determination unit 23 receives a reservable bandwidth S in its own router from the reception control unit 22.
And the required bandwidth X stored in the required bandwidth storage unit 24
To determine whether only the requested bandwidth X can be reserved. Here, the reservable bandwidth S ≧ the required bandwidth X, and if reservable, the own router actually reserves only the required bandwidth X, and indicates that the required bandwidth X has been reserved without a shortage of bandwidth. The information to be indicated, for example, “OK” stamp information is stored in the reservation signaling B.

Subsequently, based on the address stored in the upstream node storage unit 25, the reservation signaling B is transmitted to the upstream node, here, the router 1 (step 3).
5). In this way, each router forming the path connecting the receiving host 4 and the transmitting host 5 determines whether or not only the requested bandwidth X can be reserved. If the reservation is possible, the bandwidth is actually reserved only for the requested bandwidth X. I do. Then, the reservation signaling B indicating the reservation completion is transferred to each upstream node.

Therefore, if the router 1 and the router 2 can reserve the bandwidth only for the requested bandwidth X, the router 1 sends a reservation signaling B indicating this to the receiving host 4.
Is transferred (step 36), after which data communication is started between the receiving host 4 and the transmitting host 5.

Next, with reference to FIG. 3, a description will be given of another operation of the first embodiment of the present invention, in which a request reserved band cannot be reserved by any router, for example, the router 2. FIGS. 3A and 3B are explanatory diagrams showing an example of the operation according to the first embodiment. FIG. 3A is a system configuration diagram, and FIG. 3B is a sequence diagram showing signaling exchange. First, similarly to the above (FIG. 2), the notification signaling A is transferred from the receiving host 4 to the transmitting host 5 (step 3).
1, 32).

Thus, the receiving host 4 and the transmitting host 5
The required bandwidth stored in notification signaling A and the individual upstream nodes are stored at each router forming the path connecting The transmitting host 5 receives the notification signaling A transferred by the router 2 (step 33), and determines whether data can be transmitted with the requested bandwidth X notified thereby.

If the transmission is possible, the reservation signaling B for instructing the reservation of the requested bandwidth X is returned by the reverse route to the notification signaling A (step 34).
The bandwidth reservation signaling processing section 21 of the router 2 receives the reservation signaling B and notifies the main determination section 23 of the reception. In response to this, the main determination unit 23 compares the reservable bandwidth Y in the own router from the reception control unit 22 with the required bandwidth X stored in the required bandwidth storage unit 24, and compares the required bandwidth X with the required bandwidth X. Judge whether only reservation is possible.

Here, the reservable bandwidth Y <the required bandwidth X
If the reservation is not possible, the information indicating the own router and the stamp information indicating the bandwidth Y reservable by the own router, for example, “R2 = Y” are stored in the reservation signaling B. Subsequently, based on the address stored in the upstream node storage unit 25, the reservation signaling B is transmitted to the upstream node, here, the router 1 (step 41).

On the other hand, in the router 1, the reservation signaling B transferred from the router 2 is received by the bandwidth reservation signaling processing section 21, and the stamp information is analyzed by the main judgment section 23. Here, if it is confirmed from the stamp information that the router 2 can reserve only a bandwidth Y smaller than the requested bandwidth X, the detour search unit 26 informs the detour search unit 26 of a detour that complements the insufficient bandwidth XY. Instruct search.

In response to this, the detour search unit 26 searches for a detour from the own router to the router 2 having a shortage of reserved bandwidth based on the routing information 27 set in advance. Here, when a detour via the router 3 is found, the insufficient bandwidth XY for the detour is searched for.
In order to make the bandwidth reservation, a new notification signaling AA is transmitted to the router 2 to the downstream router 3 (step 42).

Subsequently, a new notification signaling AA arrives at the router 2 (step 43), and a new reservation signaling BB is returned from the router 2 (step 44) in the same manner as the notification signaling A described above. If the router 3 on the way can reserve the bandwidth only for XY, a new reservation signaling BB including the stamp information indicating that is reached (step 45).

As a result, in the detour route, XY equivalent to the insufficient bandwidth
Is confirmed by the main determination unit 23 of the router 1, and the sum X + (X−Y) of the bandwidth reserved in the original path and the detour is compared with the required bandwidth X. In this case, since both are equal, it is determined that the initial requested bandwidth X has been reserved without a shortage, and the reservation signaling B indicating this is transferred from the router 1 to the receiving host 4 (step 46). Thereafter, data communication between the receiving host 4 and the transmitting host 5 is started.

As described above, the present invention introduces the concept of a connectionless resource as a method for reserving a required bandwidth, and the routers forming a path connecting the receiving host 4 and the transmitting host 5 require the required bandwidth. If it is not possible to reserve X,
This is notified to the upstream node, and the upstream node searches for a detour in the section where the bandwidth shortage occurs, and secures the insufficient bandwidth by another route.
Therefore, when there is a surplus of communication resources in another route, necessary resource reservation can be performed even when a single path having the requested bandwidth does not exist between the sending and receiving hosts.

As for a method of reserving a bandwidth in a detour for an insufficient bandwidth, new reservation signaling and notification signaling are performed between routers at both ends of the bandwidth insufficient section, for example, between router 1 and router 2. For example, the bandwidth is reserved for the detour via the router 3 in the same manner as described above. Therefore, even when the bandwidth shortage occurs in the detour due to overlap, the detour is hierarchically performed for each of the bandwidth shortage sections. To search for the missing bandwidth.

It should be noted that, in the router 1, the shortage bandwidth X
If no detour that can reserve -Y is not found, the main determination unit 23 determines that the initial required bandwidth X cannot be reserved. Then, similarly to the router 2, the information indicating the own router and the stamp information indicating the bandwidth Y that can be reserved by the own router are stored in the reservation signaling B and transmitted to the receiving host 4 corresponding to the upstream router. Notify 4.

In the above description, the case where the detour search is performed by the router to which the reservation is notified from the downstream router by the reservation signaling has been described. However, as shown in FIG. 4, it is performed by the router bandwidth management server. It may be. FIG. 4 is an explanatory diagram showing a data communication system to which a network resource reservation method according to a second embodiment of the present invention is applied. (A) is a configuration diagram showing the entire system, and (b) is a block showing a router. FIG. 3C is a block diagram showing a router bandwidth management server.

In the second embodiment, as shown in FIG. 4A, a router bandwidth management server 6 for centrally managing the bandwidth of each router constituting the network is provided, and each router notifies a change in the reserved bandwidth. And if you need a detour search,
The router bandwidth management server 6 is requested to search for a detour that can reserve the insufficient bandwidth. In response to this, based on the detour information notified from the router bandwidth management server 6, the insufficient bandwidth in the bypass The bandwidth reservation for the width is made.

As shown in FIG. 4C, the router bandwidth management server 6 manages bandwidth information indicating the bandwidth reservation status notified from each router for each router.
And a main determination unit 29 that communicates with each router to collect band information from each router. In addition, in response to a detour search request from an arbitrary router, the main determination unit 29 performs a detour that can reserve a predetermined insufficient bandwidth for a bandwidth insufficiency section based on the bandwidth information managed by the bandwidth information management unit 28. A route is searched, and the result is returned as detour information.

Next, with reference to FIG. 5, a description will be given of the operation of the second embodiment of the present invention in a case where a request reserved band cannot be reserved by any router, for example, the router 2. FIGS. 5A and 5B are explanatory diagrams showing an example of the operation according to the second embodiment. FIG. 5A is a system configuration diagram, and FIG. 5B is a sequence diagram showing the exchange of signaling. First, similarly to the above (FIG. 3), the notification signaling A is transferred from the receiving host 4 to the transmitting host 5 (steps 31 and 3).
2).

Steps 33 to 41 are the same as those in FIG. 5 described above, and a description thereof will be omitted. In the router 1, the reservation signaling B transferred from the router 2 is received by the bandwidth reservation signaling processing unit 21,
The main determination unit 23 analyzes the stamp information. Here, if it is confirmed from the stamp information that the router 2 can reserve only a bandwidth Y smaller than the requested bandwidth X, the detour search unit 26 informs the detour search unit 26 of a detour that complements the insufficient bandwidth XY. Instruct search.

In response to this, the detour search unit 26 can reserve the X-Y for the insufficiency bandwidth with respect to the router bandwidth management server 6 for the bandwidth insufficiency section, here, the section from the router 1 to the router 2. A search for a proper detour is requested (step 51). On the other hand, in response to the detour search request from the router 1, the main determination unit 29 of the router bandwidth management server 6 determines whether or not the specified bandwidth shortage section is available based on the bandwidth information managed by the bandwidth information management unit 28. A search is made for a detour that can be reserved for XY for the bandwidth.

As a result, when a route passing through the router 3 is found as a detour, detour information indicating the route is returned to the router 1. Then, when a detour via the router 3 is found, a new notification signaling AA is sent from the router 1 to the router 2 in order to reserve a bandwidth of the insufficient bandwidth XY for the detour. 3 (step 42).

Thereafter, as in FIG.
With the use of the new notification signaling AA and the new reservation signaling BB, the bandwidths X-Y corresponding to the insufficient bandwidth are reserved for the bypass route passing through the router 3 by 3 to 45. If the router 1 determines that the initial requested bandwidth X has been reserved without shortage, the router 1 transfers a reservation signaling B indicating this to the receiving host 4 (step 46). Later, receiving host 4
Data communication is started between the host and the transmission host 5.

If a detour that can reserve X-Y for the insufficient bandwidth is not found in the router bandwidth management server 6, the router 1 is notified that there is no detour. In response to this, the router 1 determines that the initial requested bandwidth X cannot be reserved, and similarly to the router 2, a stamp indicating the information indicating the own router and the bandwidth Y reservable by the own router. The information is stored in the reservation signaling B, transmitted to the receiving host 4 corresponding to the upstream router, and notified to the receiving host 4.

As described above, the router bandwidth management server 6 is provided to centrally manage the bandwidth reservation status of each router, and it is also possible to reserve an insufficient bandwidth in response to a request from an arbitrary router. , And the search result is returned to the router, so that the presence or absence of a detour can be efficiently determined without failure on the way, and the time required for the detour search can be reduced.

[0045]

As described above, the present invention generally comprises
Each router that forms a path connecting the first host and the second host by introducing the concept of connectionless resources to a protocol for performing data communication by reserving a necessary bandwidth using a single path, If the requested bandwidth cannot be reserved, the upstream router is notified of the fact, and the upstream router searches for a detour in the section where the bandwidth is insufficient, and secures the insufficient bandwidth by another route. It is something to do. Therefore, if there is a surplus of communication resources on other routes,
The necessary resource reservation can be made even if there is no single path with the required bandwidth between the sending and receiving hosts.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a data communication system to which a network resource reservation method according to a first embodiment of the present invention is applied.

FIG. 2 is an explanatory diagram showing an operation (when a bypass is not required) according to the first embodiment;

FIG. 3 is an explanatory diagram showing another operation (when a detour is necessary) according to the first embodiment;

FIG. 4 is an explanatory diagram showing a data communication system to which a network resource reservation method according to a second embodiment of the present invention is applied.

FIG. 5 is an explanatory diagram showing an operation (when a detour is required) according to the second embodiment.

[Explanation of symbols]

1-3: router, 4: reception host, 5: transmission host, 6
... router bandwidth management server, 11-15 ... link, 21 ...
Band reservation signaling processing unit, 22 ... reception control unit, 23
... A main determination unit, 24... A requested band storage unit, 25... An upstream node storage unit, 26... A detour search unit, 27.

Continuation of front page (56) References JP-A-10-257093 (JP, A) JP-A-5-63724 (JP, A) JP-A-5-22333 (JP, A) IEEE JSAC VOL. 6, NO. 9, DECEMBER 1988, pp. 1489-1499 (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/56 G06F 13/00 H04L 12/28

Claims (5)

(57) [Claims] 1. A network resource reservation method for reserving a required bandwidth required for data communication between first and second hosts connected via a plurality of routers constituting a network, wherein the first host comprises: Initiating a bandwidth reservation by sending notification signaling including the requested bandwidth to the network to the second host, wherein the second host responds to the notification signaling received from the network by the first host Sends a reservation signaling instructing reservation of the requested bandwidth notified from the network to the first host, and each router forming a predetermined path connecting the first and second hosts transmits the reservation signaling to the network. In response, the router determines whether or not a bandwidth reservation for the requested bandwidth is possible, and after adding the result to the reservation signaling, The data is sequentially transferred to the upstream router on the first host side, and the first host starts data communication after confirming the success of the reservation of the requested bandwidth by the reservation signaling received from the network. In the case where the reservation is reported from the downstream router on the second host side by reservation signaling, a detour route parallel to the section where the bandwidth is insufficient in the path is searched, and the shortage is determined using the detour route. A network resource reservation method, wherein a bandwidth is reserved for a bandwidth footprint. 2. The flow control method according to claim 1, wherein each router stores a requested bandwidth notified by the notification signaling in response to receiving the notification signaling, and stores the requested bandwidth in response to receiving the reservation signaling. By comparing the requested bandwidth that has been set with the bandwidth that can be reserved by itself, it is determined whether or not the requested bandwidth can be reserved. If the reservation is possible, information indicating that the reservation is possible is added to the reservation signaling. In addition, when the reservation is not possible, information indicating the shortage of the bandwidth obtained from the difference between the requested bandwidth and the reservable bandwidth of the own router and information indicating that the reservation is impossible is added to the reservation signaling and transferred. How to reserve network resources. 3. The flow control method according to claim 1, wherein, among the routers, a first router is configured to receive the reservation signal from a downstream second router and notify the path if the reservation is not possible. By searching for a detour from the own router to the second router in parallel with the bandwidth shortage section, and transmitting a new notification signaling including the shortage bandwidth to the searched detour to the downstream router In response to the notification signaling received from the first router, the second router initiates a bandwidth reservation, and the second router issues a new reservation signaling for instructing the reservation of the insufficient bandwidth notified from the first router by the notification signaling. Each of the routers constituting the detour route is transmitted to the network to the first router, and in response to the new reservation signaling, the own router has a bandwidth equivalent to the insufficient bandwidth. It is determined whether or not the reservation is possible, and after adding the result to the reservation signaling, the packet is sequentially transferred to the upstream router on the first router side. A method for reserving network resources, comprising, after confirming a successful reservation, adding information indicating that a required bandwidth can be reserved for the path to the reservation signaling and transferring the information to the upstream router on the first host side. 4. The flow control method according to claim 3, wherein each of the routers constituting the bypass route is notified by a new reservation signaling received from the downstream router on the second router side that reservation is impossible. A network for searching for a new detour parallel to the section where the band is insufficient in the detour, and using the new detour to reserve a bandwidth for the new insufficient bandwidth. Resource reservation method. 5. The flow control method according to claim 1, further comprising a router bandwidth management server for managing a bandwidth reservation status of each router, wherein each router sequentially notifies the router bandwidth management server of its own router bandwidth reservation status. In the case where the reservation reservation is notified from the downstream router on the second host side by the received reservation signaling, the detour route capable of reserving the bandwidth for the insufficient bandwidth in the section of the path where the bandwidth is insufficient. Request to the router bandwidth management server, and based on the obtained detour information, reserve the bandwidth for the insufficient bandwidth using the detour, and the router bandwidth management server manages the bandwidth by itself. Based on the bandwidth reservation status of each router
A network resource reservation method comprising: searching for a detour which can reserve a bandwidth for an insufficient bandwidth; and returning detour information indicating the obtained detour.