JP2003037617A - Device and method for setting path - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid setting a path to a link in a congested state without increasing a control traffic quantity and to avid concentrated setting of a plurality of paths to the same link. SOLUTION: In the path setting device for a communication network, with which communication is performed after path setting without band reservation, this device is provided with a first path setting means 100a for setting a plurality of paths between a node device 100 of a transmitting side edge and a node device 101 of a receiving side edge, an information reporting means for reporting congested state information as be information on the congested state of the link only from a node device on the path set by this first path setting means 100a to the node device 100 of the transmitting side edge, and a second path setting means 100b for selectively setting one optimum path out of a plurality of paths set by the first path setting means 100a based on the congested state information of the information reporting means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a path setting device and method in a communication network for communicating after setting a path.

[0002]

2. Description of the Related Art Here, as a first conventional path setting device, an MPLS (Multi-Protocol Label Switchi), which is one of communication networks that communicates after path setting is performed.
ng) A network will be described as an example. Generally, when setting a path in an MPLS network, a link state (Link Stat
e) type routing protocol OSPF (Open
Shortest Path First) (eg RFC2328 "OSPF Versio
It is known to use n2 "). The evaluation target of OSPF is the cost of the static path to the communication destination (only the number of hops and the bandwidth of the link).

FIG. 3 shows how a path is set by using the OSPF in the first conventional path setting device. Here, the node devices 300 to 308 are LSRs (Label Switched Routers) compatible with OSPF. The bandwidth of the links 309, 310, and 311 is 1.5 Mbps, and the bandwidth of the links 312 to 318 is 64 kbps. Also, before the following operations are performed,
It is assumed that there is no pass.

The operation of path setting by OSPF in the MPLS network configured as described above will be described with reference to FIG. First, the node device 30 at the transmitting edge
0 and the node device 301 at the receiving edge
When the path is set by F, the path 319 is set up. The path 319 includes a link 309, a node device 302, a link 310, a node device 303, and a link 311.

Here, it is assumed that congestion occurs in the link 310 by transferring a huge amount of data from the node device 300 at the transmitting edge to the node device 301 at the receiving edge using the path 319. In this state, when path setting is performed using OSPF between the node device 304 of another transmission side edge and the reception side edge node device 301, the path 320 is set up. Path 320
Is composed of a link 312, a node device 302, a link 310, a node device 303, and a link 311. Using this path 320, data transfer is performed from the node device 304 at the transmitting edge to the node device 301 at the receiving edge. As a result, the congestion state on the link 310 is further deteriorated, and the transfer efficiency is significantly reduced.

As a second conventional path setting device,
A routing protocol that extends OSPF (for example, Q
Some use OSPF). QOSPF (Quality
of service extensions to OSPF) uses information about the resources of links in the communication network (bandwidth usage status) in addition to the evaluation target of OSPF. Information about this resource is periodically examined by all node devices in the communication network and broadcast throughout the communication network.

FIG. 4 shows a state in which a second conventional path setting device performs path setting using QOSPF. Here, the node devices 400 to 408 are QOSPF.
Is an LSR corresponding to. Links 409, 410, 41
1 has a bandwidth of 1.5 Mbps and links 412-4
The bandwidth of 18 is assumed to be 64 kbps. Also,
Before the following operations are performed, it is assumed that no path has been set up.

The operation of path setting by QOSPF in the MPLS network configured as described above will be described with reference to FIG. First, the node device 4 at the transmitting edge
00 and the node device 401 on the receiving side edge,
When the path is set by the SPF, the path 419 is set up. This path 419 is connected to the link 409 and the node device 40.
2, link 410, node device 403, and link 411. Here, it is assumed that congestion occurs in the link 410 by transferring a huge amount of data from the node device 400 on the transmitting side edge to the node device 401 on the receiving side edge using the path 419.

In this state, if path setting is performed using QOSPF between another edge node device 404 on the transmitting side and the node device 401 on the receiving side, link 4
The path 420 is set up in consideration of the bandwidth usage statuses of 10. This path 420 includes the link 416 and the node device 40.
7, link 417, node device 408, and link 418. By using this path 420, the node device 404 on the transmission side edge to the node device 401 on the reception side edge
The data will be transferred to. As a result, the link 410 in the congested state can be avoided, and efficient data transfer and resource utilization can be performed.

In the conventional example described above, 1
Although the case where a congestion state has already occurred on the second path has been explained, the congestion state does not occur due to the first path, but the link utilization is very high, and the second path extends over the same link. The same is true in the case where a congestion state occurs at the point of time when it is taken.

[0011]

However, in the first conventional path setting device, only the cost of the static path to the communication destination (the number of hops and the bandwidth of the link) is evaluated, and each link is evaluated. Since it does not consider the information about the available bandwidth capacity of, even if the set path is congested, there is no effective means to avoid it, and there is a possibility that the path will be concentrated locally. Since it is expensive, there is a problem that the links of the entire communication network cannot be used evenly and efficiently.

Further, in the second conventional path setting device, since all the node devices have to frequently broadcast the resource information of neighboring links to the entire communication network, control for path setting is performed. There is a problem that the traffic volume increases.

The present invention has been made in view of the above points, and avoids setting a path on a link in a congested state without increasing the amount of control traffic, and a plurality of paths on the same link. It is an object of the present invention to provide a path setting device and method capable of avoiding intensive setting of a path. It is another object of the present invention to provide a path setting device and method that can avoid setting a path that cannot secure a reserved bandwidth without increasing the control traffic amount.

[0014]

A path setting device of the present invention is a path setting device of a communication network that communicates after performing path setting without bandwidth reservation, in a node device of a transmitting side edge and a node of a receiving side edge. Only the first path setting means for setting a plurality of paths to the device and the node device on the path set by the first path setting means are only for the node device at the transmission side edge. One of the plurality of paths set by the first path setting unit based on the congestion state information of the information notifying unit, the information notifying unit notifying the congestion state information that is the information about the congestion state of the link And a second path setting means for selecting and setting an optimum path.

According to this structure, one optimum path is selected and set from the plurality of paths set by the first path setting means based on the congestion state information of the information notifying means. It is possible to avoid setting a path on a link in a congested state without increasing the traffic amount, and to avoid setting a plurality of paths on the same link in a concentrated manner.

The path setting device of the present invention is a path setting device of a communication network that communicates after performing path setting with bandwidth reservation, and a plurality of node devices between a transmitting edge node and a receiving edge node device. First to set the path
Of the path setting means and the node device on the path set by the first path setting means, the band reservation status information which is the information about the band reservation status only for the node device of the transmission side edge. Information notification means for notification,
Second path setting means for selecting and setting one optimal path from the plurality of paths set by the first path setting means based on the bandwidth reservation status information of the information notifying means, Adopt a configuration that has.

According to this structure, only the node device on the path set by the first path setting means is provided with the band reservation status information which is the information about the band reservation status only for the node device at the transmission side edge. Notification is made and one optimum path is selected and set from the plurality of paths set by the first path setting means based on the bandwidth reservation status information, so that the reservation is made without increasing the control traffic volume. It is possible to avoid setting a path that cannot secure a band.

A path setting method according to the present invention is a path setting method for a communication network in which communication is performed after path setting without band reservation is performed. Information about link congestion status only for the node device on the transmitting side edge only in the first path setting step of setting the path of the first path and the node apparatus on the path set in the first path setting step And an information notifying step of notifying the congestion state information, and selecting one optimal path from the plurality of paths set in the first path setting step based on the congestion state information in the information notifying step. And a second pass setting step of setting by setting.

According to this method, one optimum path is selected and set from the plurality of paths set in the first path setting step based on the congestion state information in the information notifying step. It is possible to avoid setting a path on a link in a congested state without increasing the traffic amount, and to avoid setting a plurality of paths on the same link in a concentrated manner.

The path setting method of the present invention is a path setting method of a communication network for communicating after performing path setting accompanied by bandwidth reservation, wherein a plurality of nodes are provided between a node device at an edge of a transmission side and a node device at an edge of a reception side. First to set the path
And the node device on the path set in the first path setting process, the bandwidth reservation status information that is the information about the bandwidth reservation status only for the node device at the transmission side edge. An information notifying step of notifying, and a second one of selecting and setting one optimal path from the plurality of paths set in the first path setting step based on the bandwidth reservation status information in the information notifying step And a path setting step.

According to this method, only the node device on the path set in the first path setting step sends the band reservation status information which is the information about the band reservation status only to the node device at the transmitting side edge. Notification is made and one optimal path is selected and set from the plurality of paths set in the first path setting step based on the bandwidth reservation status information, so that the reservation is made without increasing the control traffic volume. It is possible to avoid setting a path that cannot secure a band.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION A first aspect of the present invention relates to a congestion state of a link only to a node device on an edge of a transmission side where only node devices on a plurality of paths set by a path setting means. Notify the congestion state information that is information,
Based on this congestion state information, one optimum path is selected and set from the plurality of paths set by the path setting means.

The second gist of the present invention is that only the node devices on a plurality of paths set by the path setting means are related to the bandwidth reservation status only for the node device on the transmission side edge. Notify a certain bandwidth reservation status information,
Based on this bandwidth reservation status information, one optimum path is selected and set from the plurality of paths set by the path setting means.

The first embodiment of the present invention will be described in detail below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing the configuration of a path setting device according to Embodiment 1 of the present invention. The path setting device according to the first embodiment of the present invention is applied to a communication network that communicates after performing path setting without bandwidth reservation. An MPLS network is an example of this communication network.

As shown in FIG. 1, this communication network includes a plurality of node devices 100 to 108 and a plurality of links 109 to which connect the node devices 100 to 108.
And 118. The node devices 100 to 108 are LSRs having the functions of the present invention. The transmission-side edge node devices 100 and 104 correspond to the reception-side edge node device 10.
First path setting means 1 for setting a plurality of paths between
It has 00a and 104a.

Node devices 102, 103, 105-10
8 is information notification means 102a, 103a, 105a-1
08a. These information notifying means 102a,
103a and 105a to 108a are node devices 100,
When it is on the path set by the first path setting means 100a, 104a of 104, only the node devices 100, 104 at the transmitting edge are notified of the congestion status information which is the information regarding the congestion status of the link.

Further, the node device 100 at the transmitting side edge,
The reference numeral 104 includes second path setting means 100b and 104b. These second path setting means 100b, 10
4b is information notification means 102a, 103a, 105a-
Based on the congestion state information of 108a, one optimum path is selected and set from the plurality of paths set by the first path setting means 100a and 104a.

The bandwidth of the links 109, 110 and 111 is 1.5 Mbps, and the bandwidth of the links 112 to 118 is 64 kbps. Before the following operation is performed, it is assumed that no path is set up.

The operation of an example of path setting according to the present invention in the MPLS network configured as described above will be described with reference to FIG. First, the operation when setting a path between the node device 100 at the transmitting edge and the node device 101 at the receiving edge will be described. The first path setting unit 100a sets two paths 119 and 121 using OSPF between the node device 100 on the transmission side edge and the node device 101 on the reception side edge. Path 119
Is composed of a link 109, a node device 102, a link 110, a node device 103, and a link 111. Pass 12
1 is a link 113, a node device 105, and a link 114.
And the node device 106 and the link 115. In addition,
The first path setting means 100a may set three or more paths.

Then, these two paths 11 that have been set
Node devices 102, 103, 105 above the 9, 121,
106 information notification means 102a, 103a, 105a,
Only the node 106a notifies the node device 100 at the transmitting edge only of the information (usable bandwidth) about the link usage status, that is, the congestion status information that is information about the link congestion status. For example, the second path setting unit 100b of the node device 100 at the transmitting edge determines the path 119 as the optimum path based on the congestion state information, selects the path 119, and releases the path 121.

Using the path 119 thus selected, the node device 100 at the transmitting edge transfers data to the node device 101 at the receiving edge. Here, it is assumed that a huge amount of data is transferred from the node device 100 at the transmitting edge to the node device 101 at the receiving edge, so that a congestion state occurs in the link 110.

Next, in this state, the operation when the path setting according to the present invention is performed between the node device 104 at another transmitting edge and the node device 101 at the receiving edge will be described. Between the node device 104 on the transmitting side edge and the node device 101 on the receiving side edge, the first path setting means 104a uses the OSPF to provide two paths 12
0 and 122 are set. The path 120 includes a link 112, a node device 102, a link 110, a node device 103, and a link 111. Path 122 is link 116
And node device 107, link 117, and node device 108
And link 118. The first path setting means 104a may set three or more paths.

Then, these two paths 12 that have been set
Node devices 102, 103, 107 above 0, 122,
108 information notification means 102a, 103a, 107a,
Only the node 108a notifies the node device 104 on the transmission side edge of the information (usable band) about the link usage status, that is, the congestion status information that is information about the congestion status of the link. In this case, pass 120
Informs that the link 110 is in a congested state and the data transfer efficiency is poor, and the path 122 transmits information that a congested state does not occur in any of the links and smooth data transfer is possible. The node device 104 at the side edge is notified. As a result, the second path setting unit 104b of the node device 104 at the transmitting edge determines that the path 122 is the optimum path based on the congestion state information,
The path 122 is selected and set, and the path 120 is released.

Using the path 122 selected in this way, the node device 104 at the transmitting edge transfers data to the node device 101 at the receiving edge. As a result, it is possible to avoid the link 110 in the congested state without increasing the control traffic amount, so that efficient data transfer and resource utilization can be performed.

In the first embodiment, the case where the congestion state has already occurred on the first path has been described. The congestion state does not occur on the first path, but the link utilization rate is very high. Even if congestion occurs when the second path is set up on the same link,
The present invention can be applied.

Also, in the first embodiment, the node device 101 is also provided with the first path setting means and the second path setting means having the same configurations as the first path setting means 100a and the second path setting means 100b. It can also be configured to. In this case, the node device 101 serves as a node device at the transmitting edge, and the node device 100 serves as a node device at the receiving edge, and the first path setting means of the node device 101 sets a plurality of paths. Only the node device on the path set by the path setting means of the above notifies the node device 101 at the transmitting edge only of the congestion state information which is the information about the congestion state of the link, and the node device 10
The first second path setting means may select and set one optimum path from the plurality of paths set by the first path setting means of the node device 101 based on the congestion state information. it can.

In the first embodiment of the present invention, the node device at the transmitting edge sets a plurality of paths, and based on the congestion state information of each path notified from the node device on the set path. By selecting the optimum path, it is possible to avoid a link in a congested state without increasing control traffic, and to avoid a plurality of paths being intensively set on the same link.

(Second Embodiment) FIG. 2 is a block diagram showing a configuration of a path setting device according to a second embodiment of the present invention. The path setting device according to the second embodiment of the present invention is applied to a communication network that communicates after performing path setting with bandwidth reservation. As this communication network, for example, MP that reserves a band by RSVP or the like
There is an LS network.

As shown in FIG. 2, this communication network includes a plurality of node devices 200 to 208 and a plurality of links 209 to which these node devices 200 to 208 are connected.
218 and 218.

The node devices 200 to 208 are LSRs having the functions of the present invention. Node device 2 at the transmitting edge
00 and 204 are node devices 200 and 2 on the transmission side edge.
04 and the node device 201 at the receiving edge, first path setting means 200a, 204a for setting a plurality of paths.
have.

Node devices 202, 203, 205-20
8 is information notification means 202a, 203a, 205a-2
08a. These information notifying means 202a,
203a and 205a to 208a are node devices 200,
When it is on the path set by the first path setting means 200a, 204a of 204, the bandwidth reservation status information, which is information regarding the bandwidth reservation status, is notified only to the node devices 200, 204 at the transmitting edge.

Further, the node device 200 at the transmission side edge,
204 has second path setting means 200b and 204b. These second path setting means 200b, 20
4b is information notification means 202a, 203a, 205a-
Based on the bandwidth reservation status information of 208a, one optimum path is selected and set from the plurality of paths set by the first path setting means 200a and 204a.

It is assumed that the links 209, 210 and 211 have a bandwidth of 1.5 Mbps and the links 212 to 218 have a bandwidth of 64 kbps. Before the following operation is performed, it is assumed that no path is set up.

The operation of an example of path setting according to the present invention in the MPLS network configured as described above will be described with reference to FIG. First, the operation when setting a path between the node device 200 at the transmitting edge and the node device 201 at the receiving edge will be described. The first path setting unit 200a sets two paths 219 and 221 between the node device 200 on the transmitting side edge and the node device 201 on the receiving side edge using OSPF. Path 219
Is composed of a link 209, a node device 202, a link 210, a node device 203, and a link 211. Path 22
1 is a link 213, a node device 205, and a link 214.
And a node device 206 and a link 215. In addition,
The first path setting means 200a may set three or more paths.

Then, these two paths 21 that have been set
Node devices 202, 203, 205 above 9, 221;
Information notification means 202a, 203a, 205a of 206,
Only 206a notifies the bandwidth reservation status information, which is information regarding the bandwidth reservation status, only to the node device 200 at the transmitting edge. For example, the second path setting unit 200b of the node device 200 at the transmitting edge determines that the path 219 is the optimum path based on the congestion state information, selects and sets the path 219, and releases the path 221.

Using the path 219 selected in this way, the node device 200 at the transmitting edge transfers data to the node device 201 at the receiving edge. Here, it is assumed that a huge amount of data is transferred from the node device 200 on the transmitting side edge to the node device 201 on the receiving side edge, so that a congestion state occurs in the link 210.

Next, in this state, the operation when the path setting according to the present invention is performed between the node device 204 of another transmitting edge and the node device 201 of the receiving edge will be described. Between the node device 204 on the transmitting side edge and the node device 201 on the receiving side edge, the first path setting means 204a uses the OSPF to provide two paths 22
Set 0 and 222. The path 220 includes a link 212, a node device 202, a link 210, a node device 203, and a link 211. The path 222 is the link 216
And node device 207, link 217, and node device 208
And link 218. The first path setting means 204a may set three or more paths.

Then, these two paths 22 that have been set
Node devices 202, 203, 207 above 0, 222,
208 information notification means 202a, 203a, 207a,
Only 208a notifies bandwidth reservation status information, which is information regarding the bandwidth reservation status, only to the node device 204 at the transmitting edge. In this case, the path 220 informs that the link 210 is in a congested state and the data transfer efficiency is poor, and no congested state has occurred in any of the links from the path 222, and smooth data transfer is possible. The node device 2 at the transmission-side edge has information that it is possible.
04 will be notified. As a result, the second path setting unit 200b of the node device 204 at the transmitting edge determines the path 222 as the optimum path based on the congestion state information, selects and sets the path 222, and releases the path 220. .

Using the path 222 thus selected, the node device 204 at the transmitting edge transfers data to the node device 201 at the receiving edge. As a result, it is possible to avoid setting a path that cannot secure the reserved bandwidth without increasing the control traffic amount.

In the second embodiment, the node device 201 is also provided with the first path setting means and the second path setting means having the same configurations as the first path setting means 200a and the second path setting means 200b. It can also be configured to. In this case, the node device 201 serves as a node device at the transmission edge, and the node device 200 serves as a node device at the reception edge, and the first path setting means of the node device 201 sets a plurality of paths. Only the node device on the path set by the path setting means of 1 notifies the node device 201 at the transmitting side edge of the band reservation status information which is the information about the band reservation status, and the node device 2
The second path setting unit 01 may select and set one optimum path from the plurality of paths set by the first path setting unit of the node device 201 based on the congestion state information. it can.

[0052]

As described above, according to the present invention,
Increases the amount of control traffic because the node device at the transmitting edge sets multiple paths and selects the optimal path based on the congestion status information of each path notified from the node device on the set path It is possible to avoid setting a path on a link in a congested state without doing so and to prevent a plurality of paths from being intensively set on the same link.

Further, according to the present invention, the node device at the transmitting edge sets a plurality of paths, and is optimized based on the bandwidth reservation status information of each path notified from the node device on the set paths. Since such a path is selected, it is possible to avoid setting a path that cannot secure the reserved bandwidth without increasing the control traffic amount.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a path setting device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a path setting device according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a first conventional path setting device.

FIG. 4 is a block diagram showing a configuration of a second conventional path setting device.

[Explanation of symbols]

100 to 108 Node device 100a First path setting means 100b Second path setting means 102a, 103a, 105a to 108a Information notifying means 104a First path setting means 104b Second path setting means 109 to 118 Links 200 to 208 Node device 200a First path setting means 200b Second path setting means 202a, 203a, 205a to 208a Information notifying means 204a First path setting means 204b Second path setting means 209 to 218 Link

Claims (4)

[Claims] 1. A path setting device of a communication network for communicating after performing path setting without bandwidth reservation,
A first path setting means for setting a plurality of paths between the node device on the transmitting side edge and the node device on the receiving side edge;
Information notifying means for only the node device on the path set by the first path setting means to notify the congestion state information which is the information about the congestion state of the link only to the node device at the transmission side edge, Second path setting means for selecting and setting one optimal path from the plurality of paths set by the first path setting means based on the congestion state information of the information notifying means. A path setting device characterized by: 2. A path setting device of a communication network, which communicates after performing path setting accompanied by bandwidth reservation, wherein a plurality of paths are set between a node device of a transmitting side edge and a node device of a receiving side edge. Of the path setting means and the node device on the path set by the first path setting means, the band reservation status information which is the information about the band reservation status only for the node device of the transmission side edge. Information notifying means for notifying, and second setting and selecting one optimum path from the plurality of paths set by the first path setting means based on the bandwidth reservation status information of the information notifying means A path setting device comprising: 3. A path setting method of a communication network for communicating after performing path setting without bandwidth reservation,
A first path setting step of setting a plurality of paths between the node device on the transmitting side edge and the node device on the receiving side edge;
An information notifying step in which only the node device on the path set in the first path setting step notifies the congestion state information which is the information regarding the congestion state of the link only to the node device at the transmitting edge, A second path setting step of selecting and setting one optimal path from the plurality of paths set in the first path setting step based on the congestion state information in the information notifying step. A path setting method characterized by: 4. A path setting method for a communication network, which performs communication after performing path setting with bandwidth reservation, wherein a plurality of paths are set between a node device at a transmitting side edge and a node device at a receiving side edge. And the node device on the path set in the first path setting process, the bandwidth reservation status information that is the information about the bandwidth reservation status only for the node device at the transmission side edge. An information notifying step of notifying, and a second one of selecting and setting one optimal path from the plurality of paths set in the first path setting step based on the bandwidth reservation status information in the information notifying step The path setting process of
A path setting method comprising: