JP2012054730A - Communication apparatus, network, and autonomous distributed routing control method and program for use with them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication apparatus that can increase the possibility of continuing the same service as before a link band reduction when a link band reduces even in the case of fewer available network bands.SOLUTION: The communication apparatus (NE203) for use in a network having a variable link band includes means (apparatus controlling section 11, signaling section 12, routing section 13, path managing section 14, link managing section 15, rerouting section 16) for controlling routing autonomously distributedly in response to a change in the link band.

Description

  The present invention relates to a communication device, a network, an autonomous distributed route control method used therefor, and a program thereof, and more particularly to an autonomous distributed route control method adapted to a network having a variable link bandwidth.

  In recent years, autonomous distributed control networks represented by MPLS (Multi-Protocol Label Switching), GMPLS (Generalized MPLS), and ASON (Automatic Switch Optical Network) have been put into practical use (see, for example, Patent Document 1).

  In these autonomous distributed control networks, OSPF-TE (Traffic Engineering Extensions to OSPF (Open Shortest Path First)) and IS-IS-TE (Intermediate System-to-Intermediate System Traffic Routing) are used. (For example, refer patent document 2).

  In addition, path management (configuration / maintenance) is represented by RSVP-TE (Resource reServation Protocol with Traffic Engineering Extension) and CR-LDP (Constrained-based Routed Label Distribution Protocol).

  In recent years, a mechanism for automatically changing a link band represented by AMR (Adaptive Modulation Radio) and LAG (Link Aggregation Group) has been put into practical use and used. AMR is a technology that automatically changes the available bandwidth in accordance with the wireless channel quality. LAG is a link redundancy technique that bundles a plurality of physical links and manages them as one logical link. When a failure occurs in a physical link related to a logical link for which LAG is set, the bandwidth of the logical link is automatically reduced.

JP 2009-077719 A JP 2004-040384 A

  In an autonomous distributed control network represented by MPLS, GMPLS, and ASON, in a network that uses a mechanism that changes the link bandwidth represented by AMR, LAG, etc. There is a problem that the necessary bandwidth of the path cannot be secured.

  An example of the problem of the network will be shown. In the example shown in FIG. 11, a case is shown in which a path 1 of band 2 and a path 2 of band 1 are set for a link of link band 3. In this case, when the link bandwidth is reduced by 1, using the above-described autonomous decentralized control reroute mechanism, the route route of the bandwidth 2 is searched and rerouted.

  For this reason, in order to secure the set path bandwidth before reducing the link bandwidth, two or more free bandwidths of the link between the transmission source node and the transmission destination node are required. In the above autonomous decentralized control reroute mechanism, the granularity of reroute when the link bandwidth decreases is in units of paths, so if the bandwidth of the reroute target path is large, the switch destination network has a lot of link bandwidth. It becomes a problem that it is necessary.

  Therefore, the object of the present invention is to solve the above-mentioned problems and increase the possibility that the same service as before the reduction of the link bandwidth can be continued when the link bandwidth is reduced even when the free bandwidth of the network is small. It is an object of the present invention to provide a communication apparatus, a network, an autonomous distributed path control method used for them, and a program thereof.

A communication device according to the present invention is a communication device used for a network having a variable link bandwidth,
Means for controlling the route in an autonomous and distributed manner according to the change in the link band is provided.

  A network according to the present invention includes the communication device described above.

An autonomous distributed route control method according to the present invention is an autonomous distributed route control method used for a communication device used in a network having a variable link bandwidth,
The communication apparatus executes a process of controlling a path in an autonomous and distributed manner according to the change in the link band.

A program according to the present invention is a program to be executed by a computer in a communication device used for a network having a variable link bandwidth,
The method includes a process of controlling a route in an autonomous and distributed manner according to the change in the link band.

  The present invention is configured and operated as described above, so that even when the available bandwidth of the network is small, when the link bandwidth is reduced, the same service as before the reduction of the link bandwidth (service of the same bandwidth) It is possible to increase the possibility that the process can be continued.

It is a functional block diagram which shows the structural example of the communication apparatus by embodiment of this invention. It is a figure which shows the structural example of the logical link information table in communication apparatus NE203 shown in FIG. It is a figure which shows the structural example of the physical link information table in communication apparatus NE203 shown in FIG. It is a figure which shows the structural example of the path | pass information table in communication apparatus NE203 shown in FIG. It is a figure which shows the characteristic of embodiment of this invention. It is a figure which shows an example of the network structure by embodiment of this invention. It is a figure which shows the other example of the network structure by embodiment of this invention. It is a figure which shows the relationship between the physical link and logical link in embodiment of this invention. It is a figure which shows the relationship (after band reduction) of the physical link and logical link in embodiment of this invention. It is a flowchart which shows the operation | movement at the time of the link bandwidth reduction | decrease in the node by embodiment of this invention. It is a figure which shows an example of the problem of the network relevant to this invention.

  Next, embodiments of the present invention will be described with reference to the drawings. First, an outline of an autonomous distributed route control method adapted to a network with variable link bandwidth according to the present invention will be described.

  The present invention relates to an autonomous distributed control (AMR) and adaptive mobility control (GMRLS) such as Multi-Protocol Label Switching (MPLS), Generalized MPLS (GMPLS), and Automatic Switch Optical Network (ASON). When a mechanism for changing a link band represented by the above is used as a logical link, a mechanism for controlling a path in an autonomous and distributed manner according to a change in the link band is provided.

  1 is a functional block diagram showing a configuration example of a communication device according to an embodiment of the present invention, FIG. 2 is a diagram showing a configuration example of a logical link information table in the communication device NE 203 shown in FIG. 1, and FIG. FIG. 4 is a diagram illustrating a configuration example of a physical link information table in the communication device NE203 illustrated in FIG. 1, and FIG. 4 is a diagram illustrating a configuration example of a path information table in the communication device NE203 illustrated in FIG.

  In FIG. 1, a communication device NE203 is an autonomous distributed control compatible node (NE) in the embodiment of the present invention. The communication device NE203 includes a device control processing unit 11, a signaling processing unit 12, a routing processing unit 13, a path management processing unit 14, a link management processing unit 15, a reroute processing unit 16, and a storage unit 17. The storage unit 17 includes a path information storage unit 171, a link information storage unit 172, and other various information storage units 173.

  The link information storage unit 172 is a storage unit that stores the logical link information table shown in FIG. 2 and the physical link information table shown in FIG. The logical link information table stores information on logical links connected to the own node, and includes “link ID”, “connection destination node ID”, “maximum bandwidth”, “in-use bandwidth”, “available bandwidth”. ”,“ Unusable bandwidth ”, and“ other link related information ”.

  The physical link information table stores information on physical links connected to the own node, and includes “link ID”, “connection destination node ID”, “maximum bandwidth”, “used bandwidth”, “available bandwidth”. ”,“ Unusable bandwidth ”,“ related logical link ID ”, and“ other logical link related information ”.

  “Link ID” is an identifier that makes a link unique within each node. The “connection destination node ID” is a node identifier to which the link is connected (the “connection destination node ID” is unique within the network).

  “In-use band” indicates a band used in the link. The “in-use band” increases when the path is set, and decreases when the path is disconnected. “Available bandwidth” indicates a bandwidth that can be used for path setting. The “unusable band” is an unusable band for path setting, and is changed by a link band mechanism represented by AMR (Adaptive Modulation Radio) or LAG (Link Aggregation Group) (the “unusable band” decreases). A typical example of this is a physical link failure). The “maximum bandwidth” is obtained by adding “available bandwidth” and “unusable bandwidth”. “Other link related information” indicates link information stored in a general node.

  The path information storage unit 171 is a storage unit that stores the path information table shown in FIG. In the path information table, path cross-connect information and other attributes of the node are stored (this information is provided in a general node for autonomous distributed control). Specifically, the path information table includes “input logical link ID”, “input label”, “output logical link ID”, “output label”, and “other path related information”.

  The other various information storage unit 173 is a storage unit that stores information held by a general autonomous distributed control compatible node.

  The device control processing unit 11 is a processing unit that transfers a command reception / response process from a maintenance system such as a network management system (NMS), a notification process to the maintenance system, and a command or signaling request to an appropriate processing unit.

  The signaling processing unit 12 and the routing processing unit 13 are processing units included in an existing autonomous distributed control compatible node.

  The signaling processing unit 12 is a signaling protocol represented by RSVP-TE (Resource reServing Protocol with Traffic Engineering Extension) and CR-LDP (Constrained-based Routed Label Protocol).

  The routing processing unit 13 implements OSPF-TE (Traffic Engineering Extensions to OSPF (Open Shortest Path First)) or IS-IS-TE (Intermediate System-to-Intermediate System Traffic Processing). .

  The path management processing unit 14 manages paths related to each node by maintaining a path information table.

  The link management processing unit 15 manages the physical link and the logical link by maintaining the physical link information table and the logical link information table. The link management processing unit 15 includes a mechanism for changing a link band represented by AMR, LAG, or the like. For this reason, the link management processing unit 15 can grasp the insufficient bandwidth of the set paths. Further, the link management processing unit 15 associates physical links with logical links.

  The reroute processing unit 16 performs path switching processing corresponding to the decrease in the link bandwidth. Although not shown, the communication device NE203 includes another existing function processing unit, and the other existing function processing unit is a processing unit of a function possessed by a general autonomous distributed control compatible node.

  FIG. 5 is a diagram illustrating features of the embodiment of the present invention, FIG. 6 is a diagram illustrating an example of a network configuration according to the embodiment of the present invention, and FIG. 7 is a diagram of a network configuration according to the embodiment of the present invention. FIG. 8 is a diagram illustrating another example, FIG. 8 is a diagram illustrating a relationship between a physical link and a logical link in the embodiment of the present invention, and FIG. 9 is a diagram illustrating a relationship between the physical link and the logical link in the embodiment of the present invention. It is a figure which shows a relationship (after band reduction). The features of the present embodiment will be described with reference to FIGS.

  In the present embodiment, it is assumed that there is a link with a maximum bandwidth of 5 and that 3 bandwidths are used. In FIG. 5, the following operation is performed in the present embodiment. (1) The available bandwidth decreases by 2. (2) The node updates the link state and advertises link state information to other nodes. (3) The available bandwidth decreases by one. (4) In this case, (in-use band) <(available band), and the service of the already set path cannot be continued. Therefore, the node can continue the service corresponding to the bandwidth of the path before the bandwidth reduction by re-routing the path corresponding to the bandwidth 1.

  In the network configuration example illustrated in FIG. 6, a case is assumed in which when there is a path NE200-NE201-NE203-NE205 having a bandwidth of 3, the bandwidth of the link between NE203 and NE205 is reduced.

  As shown in the network configuration shown in FIG. 7, the path corresponding to the band 1 that is a decrease in the link band is rerouted to the NE 200 -NE 201 -NE 202 -NE 205. When the available bandwidth of the link falls below the bandwidth necessary for continuing the service, the path corresponding to only the insufficient bandwidth is rerouted.

  6 and 7, a network configuration is shown as an embodiment of the present invention. The network configuration and functions assumed in this embodiment will be described.

  In this embodiment, an autonomous distributed control network such as MPLS / GMPLS / ASON is assumed. As shown in FIGS. 6 and 7, an autonomous distributed control compatible network such as MPLS / GMPLS / ASON is a network composed of nodes (NE), physical links and logic corresponding to autonomous distributed control such as MPLS / GMPLS / ASON. It is.

  When a path is set in the autonomous distributed control compatible network, each node (NE200 to NE206) executes route control and signaling by autonomous distributed control, performs label reservation / switch setting of each node, and designates a specified start point / Set and disconnect paths between end nodes.

  In the network assumed in the present embodiment, an end-to-end path is provided by a communication technique such as a packet, TDM (Time Division Multiplexing), or WDM (Wavelength Division Multiplexing).

  The autonomous distributed control compatible nodes (NE201 to NE206) perform cross-connect (hereinafter referred to as XC) (or switching) based on information on labels (identifiers) generated from packets, time slots, wavelengths, and the like. Further, the autonomous distributed control compatible nodes (NE201 to NE206) perform route control and path management (path setting, maintenance, and disconnection) of the autonomous distributed control path by an autonomous distributed control protocol such as MPLS / GMPLS / ASON.

  The autonomous distributed control compatible nodes (NE201 to NE206) are connected by one or more physical links such as optical fibers. A plurality of physical links are bundled to form a logical link.

  8 and 9 show examples of the relationship between physical links and logical links. In this embodiment, three physical links PL001 (band 1), PL002 (band 1), and PL003 (band 3) are bundled to form one logical link LL20320501 in band 5. If the physical link PL001 of the physical links constituting the logical link LL20320501 becomes unusable for some reason, the bandwidth of the logical link LL20320501 is 4.

  8 and 9, the link is described as a wired image, but there are cases where the bandwidth of the logical link is similarly reduced even in a wireless link using a technique such as AMR. In addition, the nodes supporting autonomous distributed control are connected by a control message exchange link.

  The physical link is a link through which user information passes, while the control message exchange link is a link used for exchanging control information between autonomous distributed control compatible nodes (NE201 to NE206). Depending on the network operation method, the communication link and the control message exchange link may share the same physical link.

  FIG. 10 is a flowchart showing the operation when the link bandwidth is reduced in the node according to the embodiment of the present invention. The operation of communication apparatus NE203 according to the embodiment of the present invention will be described with reference to FIGS. Note that the processing operation shown in FIG. 10 is also realized by a CPU (central processing unit) (not shown) in the communication device NE203 shown in FIG. 1 executing a program.

  The link management processing unit 15 detects a decrease in physical links (step S1 in FIG. 10). The link management processing unit 15 updates the bandwidth information of the corresponding link ID in the physical link information table. Then, the link management processing unit 15 updates the bandwidth information of the link ID of the logical link corresponding to the physical link whose bandwidth has been reduced in the logical link information table (step S2 in FIG. 10).

  The link management processing unit 15 notifies the routing processing unit 13 that the bandwidth of the logical link has been reduced, and the routing processing unit 13 transmits the link state information to the other by a routing protocol such as OSPF-TE or IS-IS-TE. Advertising to the communication device (step S3 in FIG. 10).

  The link management processing unit 15 refers to the logical link information table and determines (in-use bandwidth)> (available bandwidth) for the link ID of the link whose available bandwidth has decreased (step S4 in FIG. 10). If (in-use bandwidth)> (available bandwidth) (YES in step S4 in FIG. 10), it indicates that the already set path bandwidth cannot be secured. On the other hand, if (in-use bandwidth) <(available bandwidth) (NO in step S4 in FIG. 10), it indicates that the bandwidth of the already set path can be secured.

  When (in-use band)> (available band), the following processing is performed. The link management processing unit 15 calculates the insufficient bandwidth (= used bandwidth−available bandwidth). The link management processing unit 15 notifies the reroute processing unit 16 of the “insufficient bandwidth” and the “link ID of the link whose bandwidth has been reduced”. The reroute processing unit 16 requests the routing processing unit 13 to calculate a switching destination route for the insufficient bandwidth path, and requests the signaling processing for switching to the signaling processing unit 12, thereby causing the insufficient bandwidth path. The reroute process is performed (step S5 in FIG. 10).

  In the above processing, notifications, requests, etc. from the link management processing unit 15 to the signaling processing unit 12, the routing processing unit 13, and the reroute processing unit 16 are made through the device control processing unit 11.

  As described above, in this embodiment, when the available bandwidth of the link falls below the bandwidth necessary for continuing the service, the path corresponding to only the insufficient bandwidth is rerouted. Even in a few cases, when the link bandwidth is reduced, there is a high possibility that the same service (service of the same bandwidth) as that before the reduction of the link bandwidth can be continued.

  In the present embodiment, the above-described operation is realized by the reroute processing unit 16 knowing the insufficient bandwidth from the mechanism for changing the link bandwidth represented by AMR, LAG, and the like.

  In this embodiment, when the link bandwidth decreases, the link bandwidth is immediately advertised using a routing protocol such as OSPF-TE or IS-IS-TE, and each node uses the link accurately. Since the possible bandwidth can be ascertained, it is possible to prevent a failure in path setting by signaling in an autonomous distributed control network represented by MPLS, GMPLS, and ASON.

11 Device control processing unit
12 Signaling processing unit
13 Routing processor
14 Path management processor
15 Link management processor
16 Reroute processing part
17 Memory unit
171 Path information storage unit
172 Link information storage unit
173 Various other information storage units NE200 to NE206 Communication device

Claims (10)

A communication device used in a network having a variable link bandwidth,
A communication apparatus comprising means for controlling a path in an autonomous and distributed manner according to a change in the link band.   The means for controlling the path in an autonomous distributed manner includes a means for detecting a decrease in the bandwidth of the physical link, and a link state information indicating that the bandwidth of the logical link corresponding to the physical link in which the decrease in the bandwidth is detected is decreased. Means for advertising the path by the routing protocol, means for calculating the insufficient bandwidth when the bandwidth reduction already detected cannot be ensured by detecting the decrease in the bandwidth, and re-routing the calculated path of the insufficient bandwidth The communication apparatus according to claim 1, further comprising means for performing processing.   3. The communication according to claim 2, wherein the means for performing the reroute processing performs the reroute processing by calculating a switching destination route of the shortage bandwidth path and signaling processing for the switching. apparatus.   The network is an autonomous distributed control network represented by MPLS (Multi-Protocol Label Switching), GMPLS (Generalized MPLS), and ASON (Automatic Switch Optical Network), and is at least AMR (Adaptive Modal G). The communication apparatus according to any one of claims 1 to 3, wherein a mechanism for changing a link band of (1) is used as a logical link.   A network comprising the communication device according to claim 1. An autonomous distributed path control method used for a communication device used in a network having a variable link bandwidth,
An autonomous distributed route control method, wherein the communication device executes a process of controlling a route in an autonomous distributed manner according to a change in the link band.   The link state information indicating that the bandwidth of the logical link corresponding to the physical link in which the decrease in the bandwidth is detected, and the processing of detecting the bandwidth of the physical link in the autonomously distributed control processing are detected. A process of advertising the path by the routing protocol, a process of calculating the insufficient bandwidth when the bandwidth of the already set path cannot be secured by detecting the decrease in the bandwidth, and the reroute of the calculated path of the insufficient bandwidth The autonomous distributed route control method according to claim 6, further comprising: a process for performing the process.   8. The autonomous system according to claim 7, wherein in the process of performing the reroute process, the reroute process is performed by calculating a path switching destination path of the insufficient bandwidth path and a signaling process for the switching. Distributed route control method.   The network is an autonomous distributed control network represented by MPLS (Multi-Protocol Label Switching), GMPLS (Generalized MPLS), and ASON (Automatic Switch Optical Network), and is at least AMR (Adaptive Modal G). 9. The autonomous distributed route control method according to claim 6, wherein a mechanism for changing the link band of (1) is used as a logical link. A program to be executed by a computer in a communication device used for a network having a variable link bandwidth,
A program comprising a process of controlling a route in an autonomous and distributed manner according to a change in the link bandwidth.

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