KR100560755B1 - Apparatus and method for automatically reconfiguration path - Google Patents

Abstract

The present invention relates to a specific label in a network to which a Multi Protocol Label Switching-Traffic Engineering (MPLS-TE) scheme and a Resource ReserVation Protocol Traffic Engineering (RSVP-TE) scheme are applied. The LSP is set by calculating an explicit path that satisfies a request bandwidth included in an explicit path condition for establishing a switched switched path (LSP), and specifies a candidate having a hop count less than the hop count of the explicit path. Calculates a path to store information about the candidate specified path, and detects that the bandwidth of an unsuitable link that does not satisfy the request bandwidth among a plurality of links constituting the candidate specified path is changed according to a network environment, and thus changed; If the bandwidth of the link meets the request bandwidth It resets the LSP according to the explicit route candidate.

Explicit path, candidate explicit path, bandwidth

Description

Apparatus and method for automatically reconfiguration path}             

1 is a view showing the configuration of a network routing apparatus to which conventional MPLS-TE and RSVP-TE are applied;

2 is a view showing a conventional rerouting process,

3 is a view showing the configuration of a route setting device according to an embodiment of the present invention;

4A is a diagram illustrating a configuration of a candidate explicit path information first table according to an embodiment of the present invention;

4B is a diagram showing the configuration of a candidate explicit path information second table according to an embodiment of the present invention;

5 is a view showing a rerouting process according to an embodiment of the present invention;

6 illustrates a path between multiple routers in accordance with an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

300: path selection module 310: candidate optimal path database

320: OSPF-TE 330: RE database

340: RSVP-TE 350: CSPF path calculator

360: SPF Path Calculator

The present invention relates to a network to which a Multi Protocol Label Switching-Traffic Engineering (MPLS-TE) scheme and a Resource ReserVation Protocol Traffic Engineering (RSVP-TE) scheme are applied. An apparatus and method for automatically rerouting.

Conventionally, the IP packet switching method is a connectionless IP switching method in which a router that receives data repeats a process of transmitting data through a route calculation process for determining a next router and determining a next router for each router. However, this approach started to cause congestion of Internet traffic due to the rapid increase in the number of IPs managed by one router and the amount of data waiting to be processed by the route calculation.

To solve this problem, Multi-Protocol Label Switching (MPLS), a connection-type IP switching scheme that transmits packets by switching only without a route calculation process by attaching a label with a predetermined path recorded on the packet, has been developed. By applying MPLS-TE technology, MPLS eliminates the route calculation process and reduces the IP management burden on the router, making it faster and creating a quality of service (QoS) differentiated by speed, continuity, and price. It became. Recently, as real-time services such as video are provided, RSVP-TE method is developed and applied to all routers on the service path as a signaling protocol to reserve and maintain resources (bandwidth, buffer) required for service. This became possible.

As described above, in a network to which the MPLS-TE method and the RSVP-TE method are applied, a Label Switched Path (LSP) is set in consideration of optimal conditions, but is often better because the environment of the network changes in real time. Paths with conditions may be created. This requires a process of resetting the LSP, which is now done manually, as required by the network administrator.

For example, CISCO and Riverstone provide a way for network administrators to reset the LSP only if they enter a specific Command Line Interface (CLI) that requires a rerouting.

Cisco provides CLIs for MPLS traffic-eng reoptimize, mpls traffic-eng reoptimize events {link-up}, and MPLS traffic-eng reoptimize timers frequency seconds. When the network administrator executes MPLS traffic-eng reoptimize, all currently configured traffic engineering tunnels are recalculated, and when MPLS traffic-eng reoptimize events (link-up) are performed, a specific event (link-up) occurs. All traffic engineering tunnels are recalculated and the LSP is established. If the mpls traffic-eng reoptimize timers frequency seconds are performed by the network manager, the paths of all traffic engineering tunnels are recalculated at regular intervals.

In the case of Riverstone, a network administrator creates administrator groups through the CLI, associates them with a specific LSP, and changes the management group as necessary to provide a method of recalculating the path of the corresponding LSP. .

Or, if the network administrator configures a particular router in the explicit route as a loose hop, the router configured as a loose hop causes the router to recalculate the route and reset the LSP when the router receives the RSVP route message. Doing.

However, since the path resetting process is manually performed by the network administrator as described above, even if a more efficient path is generated than the previously set LSP, it cannot be automatically detected, so it takes time until the LSP is reset by input to the manager. As much time as possible becomes inefficient use of network resources.

 Also, setting a specific node (router) as a loose hop does not work if a better path is created after the LSP is established, because the path recalculation is performed before the LSP is established. The administrator must manually set these to the loose hop.

The present invention has been made to solve the above problems, the present invention automatically detects when a better path is created after the LSP is set, and then provides a recalculated path to the node that has set the LSP LSP The purpose of this is to enable network resources to be used more efficiently.

In order to achieve the above object, the present invention transmits an explicit path condition for establishing a specific Label Switched Path (LSP), sets the LSP according to the received explicit path information, and then specifies a candidate to be received. A resource reserVation protocol traffic engineering (RSVP-TE) module for resetting the LSP according to the path information, calculating an explicit path that satisfies the request bandwidth included in the explicit path condition, and transmitting the explicit path information, and transmitting the explicit path information Computing a candidate explicit path having a hop count less than the hop count of the to store information about the candidate explicit path, the network bandwidth of the non-compliant link that does not satisfy the request bandwidth of the plurality of links constituting the candidate explicit path Detects a change in the environment and changes the bandwidth of the unsuitable link And a path selection module for transmitting the candidate specified path information if the request bandwidth is satisfied.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

First, referring to FIG. 1 and FIG. 2, the conventional general path resetting process is as follows.

1 is a view showing the configuration of a routing apparatus of a network to which conventional MPLS-TE and RSVP-TE are applied.

Referring to FIG. 1, a conventional network path setting device includes a path selection module 100 including a constrained shortes path first (CSPF) path calculator 140, and an OSPF-TE / ISIS-TE (Open Shortest Path First-). Traffic Engineering / Intermediate System to Intermediate System Traffic Engineering (110) module 110, TE (Traffic Engineering) database 120, and RSVP-TE (Resource ReserVation Protocol Traffic Engineering) module 130. The RSVP-TE module 130 requests the route selection module 100 to calculate the route when there is a route reset request from the user. The path selection module 100 calculates a new explicit path through the CSPF path calculator 140 using the information in the TE database 120 in response to the request. The path selection module 100 transmits the generated information about the specified path to the RSVP-TE module 130. The RSVP-TE module 130 generates a Resource ReserVation Protocol (RSVP) path message using the received explicit path information to reset the path.

Such a process will be described collectively with reference to FIG. 2 as follows. 2 is a diagram illustrating a conventional rerouting process, and is shown according to an operation flow of the RSVP-TE module 130.

Referring to FIG. 2, the RSVP-TE module 130 determines whether there is a rerouting request from the network manager in S201, and if so, proceeds to S202. In S202, the RSVP-TE module 130 requests a route recalculation to the route selection module 100 and proceeds to S203. In S203, the RSVP-TE module 130 receives the explicit path information calculated from the path selection module 100 and proceeds to S204. In S204, the RSVP-TE module 130 resets the path by using the received explicit path information, thereby terminating the path resetting process.

As described above, in order to perform the process of resetting a path, a network administrator's request is essential. As a result, network resources are inefficiently used. The present invention provides a rerouting device configured as shown in Figure 3 to automatically detect when a better path is generated than the set LSP due to changes in the network environment to set up a new path to solve this problem. 3 is a diagram illustrating a configuration of a path setting device according to an embodiment of the present invention.

Referring to FIG. 3, a path resetting device according to an embodiment of the present invention may include a path selection module 300 including a CSPF path calculator 350 and a SPF (Shortest Path First) path calculator 360, and a candidate. It consists of an explicit path database 310, an OSPF-TE / ISIS-TE module 320, a TE database 330, and an RSVP-TE module 340.

The RSVP-TE module 340 configures an explicit path condition for setting an explicit path for a specific LSP and transmits it to the path selection module 300, and information necessary for setting an explicit path from the path selection module 300. Set the path by receiving the explicit path information or the candidate explicit path information consisting of. The explicit path condition includes an ID of the LSP to be set, a bandwidth to be requested, and an IP address of a router corresponding to the last node of the LSP. The explicit path information is information on an LSP to be initially set according to the explicit path condition, and the candidate explicit path information is automatically specified by a network resource change according to the present invention, i.e., according to a bandwidth change of a required link. Information about the route. In the present invention, the network resource means bandwidth. And, in the present invention, a link is a path between any two routers.

When the OSPF-TE / ISIS-TE module 320 detects a change in the bandwidth of any one of the plurality of links constituting the network, the OSPF-TE / ISIS-TE module 320 informs the path selection module 300 of information on the link whose bandwidth has changed. send.

The path selection module 300 calculates an explicit path or a candidate specifying path through the CSPF path calculator 350 and the SPF path calculator 360 according to the present invention, and monitors the bandwidth change of the link at an appropriate moment. Information of each explicit path is transmitted to the RSVP-TE module 340. The CSPF path calculator 350 searches the TE database 330 according to the explicit path condition received from the RSVP-TE module 340 to calculate the explicit path. In this case, the calculated explicit path takes into account the request bandwidth during the explicit path condition. That is, an explicit path including a link satisfying the request bandwidth included in the explicit path condition is calculated. The SPF path calculator 360 calculates a candidate explicit path according to the explicit path condition. The candidate explicit path is calculated considering only a hop count between the start router and the last router of the LSP to be set regardless of the request bandwidth included in the explicit path condition. The information on the candidate specifying path is stored in the candidate specifying path database 310 only when the hop count of the candidate specifying path calculated as described above is smaller than the hop count of the explicit path calculated by the CSPF path calculator 350. .

In this case, candidate specification path information stored in the candidate specification path database 310 is as shown in FIGS. 4A and 4B.

4A is a diagram illustrating the configuration of the candidate explicit path information first table according to an embodiment of the present invention, and FIG. 4B is a diagram illustrating the configuration of the candidate explicit path information second table according to an embodiment of the present invention.

Referring to FIG. 4A, the candidate explicit path first table includes an advertising router ID 10, a link ID 20, an LSP ID 30, a request bandwidth 40, and a currently available bandwidth. It consists of 50. The advertising router ID 10 stores IDs of a plurality of routers included in the candidate specification path. The link ID 20 stores IDs of a plurality of links included in the candidate specification path and corresponds to IDs of the plurality of routers, respectively. The LSP ID 30 stores the ID of the specific LSP whose path is to be set according to the candidate specification path. The request bandwidth 40 stores a bandwidth according to the explicit path condition. The current available bandwidth 50 stores the current bandwidth of the plurality of links stored in the link ID 20, and corresponds to each link ID stored in the link ID 20.

Referring to FIG. 4B, the candidate specifying path second table includes an LSP ID 60, an invalid link number 70, and candidate specifying path router information 80. Referring to FIG. The LSP ID 60 stores an ID of an LSP having a link in which the request bandwidth 40 and the current available bandwidth 50 do not match in the first table. The number of non-conforming links 70 stores a number of links in which the request bandwidth 40 and the current available bandwidth 50 do not match among the links forming the candidate specification path associated with the LSP stored in the LSP ID 60. do. The candidate explicit path router information 80 stores IDs of a plurality of routers forming a candidate explicit path associated with an LSP stored in the LSP ID 60.

The path selection module 300 stores the candidate specifying path information first table and the candidate specifying path second table configured as described above in the candidate specifying path database 310 and then stores the OSPF-TE / ISIS-. Receiving information on any link whose bandwidth has changed from TE module 320 retrieves the tables stored in candidate candidate path database 310. The path selection module 300 compares the bandwidth of the arbitrary link with the request bandwidth 40 corresponding to the same link if there is a same link as the random link among the links stored in the table. As a result of the comparison, if the arbitrary link bandwidth is greater than or equal to the request bandwidth 40, the path selection module 300 reduces the number of invalid links 70 associated with the same link by one. Through this process, when the number of invalid links 70 becomes zero, the path selection module 300 receives the IDs of the routers stored in the candidate explicit path router information 80 associated with the same link, and the RSVP-TE module 340. To send. Accordingly, the RSVP-TE module 340 newly sets the LSP according to the candidate specification path.

That is, according to the present invention, the rerouting apparatus calculates an explicit path that satisfies the request bandwidth according to a specific LSP setting request, and sets the LSP according to the calculated explicit path. The rerouting device calculates a candidate specification path that satisfies the minimum hop count between the start router and the last router of the specific LSP.

The information on the candidate explicit path is stored only when the hop count of the candidate path is less than the hop count of the path. The information on the candidate explicit path includes IDs of a plurality of routers constituting the candidate explicit path, a plurality of link IDs, a current available bandwidth of each link, a request bandwidth, and a bandwidth not satisfying the request bandwidth. It consists of the number of invalid links which is the number of links.

Subsequently, when the bandwidth of the links constituting the network changes due to a change in the environment of the network, the rerouting apparatus searches for the stored candidate explicit path information with the same link as the link with the changed bandwidth.

If the same link as the random link is present in the stored candidate explicit path information, the rerouting apparatus compares the bandwidth of the arbitrary link with the request bandwidth, and the non-conformance is when the random link bandwidth is greater than or equal to the request bandwidth. Reduce the number of links When the number of invalid links becomes zero by repeating this process, that is, when the bandwidths of all the links constituting the candidate specifying path satisfy the request bandwidth, the rerouting apparatus resets the LSP according to the candidate specifying path. .

A series of operation processes of the rerouting apparatus of the present invention will be described with reference to FIG. 5 as follows.

5 is a diagram illustrating a rerouting process according to an embodiment of the present invention.

As shown in FIG. 5, the path selection module 300 receives an explicit path generation request and an explicit path condition for a specific LSP from the RSVP-TE module 340 and proceeds with S402 in S401. The explicit path condition includes an ID of the specific LSP, a request bandwidth, and an ID of a router corresponding to the last node of the specific LSP. In step S402, the path selection module 300 calculates an explicit path that satisfies the request bandwidth according to the received explicit path condition, and transmits information on the explicit path to the RSVP-TE module 340.

In S402, the path selection module 300 calculates a candidate specification path having a minimum hop count for the specific LSP and proceeds to S403. In step S403, the path selection module 300 compares the hop count of the explicit path with the hop count of the candidate path. If the hop count of the candidate explicit path is less than the hop count of the explicit path, the path selection module 300 proceeds to S404, and if the hop count of the candidate explicit path is larger than the hop count of the explicit path, all paths are selected. End the process. In step S404, the path selection module 300 transmits the information of the candidate specifying path to the candidate specifying path database 310 in the form of the candidate specifying path first table and the candidate specifying path second table shown in FIG. Save and proceed to S405. In step S405, the path selection module 300 determines whether to receive information on an arbitrary link whose bandwidth is changed from the OSPF-TE / ISIS-TE module 320, and when receiving the change bandwidth information for the arbitrary link, S406. Proceed. The links that make up the network change bandwidth in real time according to the surrounding environment. In S406, the path selection module 300 retrieves candidate specification path information from the candidate specification path database 310 and proceeds to S407. In step S407, the path selection module 300 determines whether the arbitrary link is the same as the bandwidth misfit link constituting the candidate specification path, and if there is the same link as the any one of the bandwidth misfit links constituting the candidate specification path, S408. If there is no link equal to the any one of the bandwidth misfit links constituting the candidate specifying path, the process proceeds to S405. In S408, the path selection module 300 compares the bandwidth of the arbitrary link bandwidth with the bandwidth of the explicit path condition, and proceeds to S409 when the arbitrary link bandwidth is greater than or equal to the bandwidth of the explicit path condition, and the random link bandwidth. If it is smaller than the bandwidth of the explicit path condition, the process proceeds to S405. In step S409, the path selection module 300 reduces the number of non-compliant links in the explicit path information by one and proceeds to S410. In step S410, the path selection module 300 checks whether the number of non-compliant links is zero, proceeds to S411 when the number of non-compliant links is zero, and proceeds to S405 when the number of non-compliant links is zero or more. From S405 to S410 is repeated. In step S411, the path selection module 300 transmits the candidate specified path information to the RSVP-TE module 340 to reset the path, thereby terminating the path setting process.

A specific embodiment in which the path is reset with the above process according to the present invention will be described with reference to FIG. 6 illustrates a path between a plurality of routers according to an embodiment of the present invention. Referring to FIG. 6, in one embodiment of the present invention, a network includes a router R1 (1), a router R2 (3), a router R3 (5), a router R4 (7), a router R5 (9), and a router R6 (11). The specific LSP is configured from router R1 (1) to router R6 (11). According to an embodiment of the present invention, the ID of the link between the routers and the currently available band of each link are indicated as the link name (link ID, link bandwidth). That is, the link between router R1 (1) and router R2 (3) is L1 (1,30), and the link between router R2 (3) and router R3 (5) is L2 (2,30) and router R3 (5). The link between router R4 (7) is L3 (3,30), the link between router R4 (7) and router R5 (9) is L4 (4,30), and the link between router R5 (9) and router R6 (11) The link between L6 (6,30), router R2 (3) and router R5 (9) is denoted by L5 (5,20). At this time, the explicit path setting condition for the specific LSP from the router R1 (1) to the router R6 (10) is as follows. The LSP ID is 1, the request bandwidth is 30, and the IP address corresponding to the last node of the LSP is R6.

The route selection module 300 includes router R1 (1), router R2 (3), router R3 (5), router R4 (7), router R5 (9), and router R6 (11) according to the explicit path setting condition. Calculate the explicit path consisting of, and sets the LSP consisting of the routers. Then, a candidate explicit path consisting of router R1 (1), router R2 (3), router R5 (9), and router R6 (11) is calculated. The path selection module 300 compares each hop count of the specified path and the candidate specified path. Since the hop count of the explicit path is five, the hop count of the candidate explicit path is three, and the hop count of the candidate explicit path is smaller, the path selection module 300 receives information of the candidate explicit path from the candidate explicit path. The database 310 stores the data in a table form. At this time, the candidate specification path first table is configured as shown in FIG. 4A. R1, R2, and R5 are stored in the advertising router ID 10, 1, 5, and 6 are stored in the link ID 20 corresponding to the router IDs sequentially, and the LSP ID 30 is 1 30 is stored in the requested bandwidth 40, and 30, 20, and 30 are sequentially stored in the currently available bandwidth 50 corresponding to the router IDs. The candidate specification path second table is configured as shown in FIG. 4B. 1 is stored in the LSP ID 60, and the link L5 between the router R2 (3) and the router R5 (9) among the links constituting the candidate explicit path does not satisfy the request bandwidth of 20 to 30. One link number 70 is stored. In addition, the candidate explicit path router information 80 stores R1, R2, and R5 which are IDs of routers constituting the candidate path.

In this state, if the bandwidth of the link L5 changes from 20 to 30, the path selection module 300 detects this and searches for the candidate specification path first table. It then confirms that the same link L5 is included. Accordingly, the path selection module 300 compares the changed current bandwidth 30 of the link L5 with the request bandwidth. In this embodiment, since the requested bandwidth is equal to the bandwidth of L5 changed to 30, the path selection module 300 reduces the number of invalid links 70 stored in the candidate specification path second table by one. Accordingly, in the present embodiment, since the number of the non-compliant links 70 becomes 0, the bandwidths of all the links constituting the candidate specifying path satisfy the request bandwidth. Thereafter, the path selection module 300 transmits the router IDs R1, R2, and R5 stored in the candidate explicit path router information 80 to the RSVP-TE module 340, whereby the router R1 (1) and router R2 ( 3) The LSP consisting of the router R5 (9) and the router R6 (11) is reset.

As such, when the LSP is set while inefficiently using the link bandwidth, the network resource is detected by automatically detecting that a better path is created and then recognizing the fact to the router that set the LSP and resetting the LSP. Can be used more efficiently.

Although described in detail with respect to preferred embodiments of the present invention, those skilled in the art to which the present invention pertains, the present invention without departing from the spirit and scope of the invention defined in the appended claims It will be appreciated that various modifications or changes can be made. Therefore, changes in the future embodiments of the present invention will not be able to escape the technology of the present invention.

As described above, according to the present invention, network resources can be used efficiently. More hop counts means more links are being used for a particular LSP, and therefore more expensive. Accordingly, the number of configurable LSPs may be reduced, or the LSP may be inefficiently set. In the present invention, the LSP may be set using a path having a low hop count, thereby enabling efficient use of resources.

In addition, it can satisfy the service requiring fast processing, and can automatically detect the better path and reset the LSP without the intervention of the network administrator.

Claims (6)

In a network to which Multi Protocol Label Switching-Traffic Engineering (MPLS-TE) and Resource ReserVation Protocol Traffic Engineering (RSVP-TE) are applied, Transmitting an explicit path condition for establishing a specific label switched path (LSP), setting the LSP according to the received explicit path information, and then resetting the LSP according to the received candidate path information. A Resource ReserVation Protocol Traffic Engineering (RSVP-TE) module; And Information on the candidate explicit path by calculating an explicit path that satisfies the request bandwidth included in the explicit path condition, transmitting the explicit path information, and calculating a candidate explicit path having a hop count less than the hop count of the explicit path; And detects that the bandwidth of the unsuitable link that does not satisfy the request bandwidth among the plurality of links constituting the candidate specifying path changes according to a network environment, and if the changed bandwidth of the unsuitable link satisfies the request bandwidth, Rerouting apparatus including a route selection module for transmitting candidate explicit route information. In a network to which Multi Protocol Label Switching-Traffic Engineering (MPLS-TE) and Resource ReserVation Protocol Traffic Engineering (RSVP-TE) are applied, Transmitting an explicit path condition for establishing a specific label switched path (LSP), setting the LSP according to the received explicit path information, and then resetting the LSP according to the received candidate path information. A Resource ReserVation Protocol Traffic Engineering (RSVP-TE) module; Calculates an explicit path that satisfies the request bandwidth included in the explicit path condition, transmits the explicit path information, calculates a candidate explicit path having a minimum hop count according to the explicit path condition, When the minimum hop count is small, information on the candidate explicit path is stored in a table form, and when a bandwidth change of an unsuitable link that does not satisfy the request bandwidth is detected among links forming the candidate path, the changed bandwidth of the non-compliant link and the request are detected. A path selection module for comparing the bandwidth and transmitting the candidate explicit path information when the changed bandwidth of the unsuitable link satisfies the request bandwidth and all the unsuitable links are removed; And And a database for storing candidate specification path information in the form of a table. The apparatus of claim 2, wherein the explicit path condition comprises an ID of the specific LSP, the request bandwidth, and an IP address of a router corresponding to the last node of the LSP. 3. The method of claim 2, wherein the information of the candidate explicit path in the form of a table includes an advertising router ID and a link ID, the LSP ID, the request bandwidth, and a current of a link forming the candidate explicit path. And a candidate specifying path second table comprising a candidate specifying path first table having available bandwidth, the LSP ID, the number of invalid links, and candidate specifying path router information. In a network to which Multi Protocol Label Switching-Traffic Engineering (MPLS-TE) and Resource ReserVation Protocol Traffic Engineering (RSVP-TE) are applied, Calculating an explicit path that satisfies a request bandwidth included in an explicit path condition for establishing a specific label switched path (LSP) and setting the LSP;  Calculating a candidate explicit path having a minimum hop count according to the explicit path condition and storing information of the candidate explicit path when the minimum hop count is less than a hop count of the explicit path; And If a change in bandwidth of an invalid link that does not satisfy the request bandwidth is detected among the links constituting the candidate path, the information of the candidate explicit path is searched and the changed bandwidth of the non-compliant link is compared with the requested bandwidth. Resetting the LSP according to the candidate specification path if the request bandwidth is satisfied and all of the invalid links are removed. 6. The method of claim 5, wherein the information of the candidate specifying path includes: an advertising router ID and a link ID, the LSP ID, the request bandwidth, and a current available bandwidth of a link constituting the candidate specifying path. And a candidate specifying path second table comprising a candidate specifying path first table, the LSP ID, the number of invalid links, and candidate specifying path router information.

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