WO2014005522A1

WO2014005522A1 - Route computation method and device

Info

Publication number: WO2014005522A1
Application number: PCT/CN2013/078763
Authority: WO
Inventors: 陈青松; 罗春; 卢刚
Original assignee: 中兴通讯股份有限公司
Priority date: 2012-07-03
Filing date: 2013-07-03
Publication date: 2014-01-09
Also published as: CN102769563B; CN102769563A

Abstract

Disclosed are a route computation method and device, the method comprising: splitting each network element node in an optical transport network (OTN) into a plurality of network element sub-nodes; allocating sub-node links for the plurality of network element sub-nodes, and constructing expansion topology information for the plurality of network element sub-nodes according to the sub-node links; and employing a constrained shortest path first (CSPF) algorithm to conduct route computation on the plurality of network element sub-nodes according to the expansion topology information. The present invention saves resources such as DXC, OEP and the like, improves the effective use rate of OXC resource, and reduces service consumption.

Description

Route calculation method and device

TECHNICAL FIELD The present invention relates to the field of communications, and in particular to a route calculation method and apparatus. BACKGROUND OF THE INVENTION A transport network is the basis of an entire telecommunications network, which provides a transmission channel and a transmission platform for services carried by the entire network. The related technologies of the transport network mainly use SDH (Synchronous Digital Hierarchy) technology and WDM (Wavelength Division Multiplexing) technology. For the advantages and disadvantages of SDH and WDM technologies, the ITU (International Telecommunication Union) has proposed an OTN (Optical Transport Network) architecture. The OTN network has the advantages of large-capacity WDM, high-speed, and long-distance transmission. It also has the advantages of rich SDH access, flexible scheduling, strong protection, and OAM (Operation Administration and Maintenance). The OTN network mainly includes the following subsystems: WDM link, OXC (Optical Cross-Connects, optical cross-connects), DXC (Digital Cross-Connects), OEP (Optical Electronic Processor), etc. . Please refer to FIG. 1. FIG. 1 is a schematic structural diagram of a typical OTN network element according to the related art. Referring to FIG. 2, FIG. 2 is a schematic diagram of a topology of an OTN network composed of OTN network elements according to the related art. When establishing a service in an OTN network, first, a wavelength switching path needs to be calculated, and wavelength assignment is performed based on the Wavelength conversion, photoelectric processing, etc. Currently, the common practice for path computation is to divide the entire path computation into three parts: route calculation, wavelength assignment, and optical damage verification. The route calculation is based on the network topology to select an appropriate route; the wavelength assignment is to allocate the available wavelengths for the route; the optical damage verification is to verify whether the optical signal meets the transmission requirements. The three parts of route calculation, wavelength assignment and optical damage verification are independent of each other, in order. In the OTN network, the exchange particles of OXC are much larger than DXC, and the ability of OXC to process signals is much larger than that of DXC and OEP. In the prior art, the network topology on which the route calculation is based is mainly composed of the WDM link and the OXC, and the resources such as DXC and OEP inside the network element are not considered, and the calculated path is for the WDM link and the OXC resource. Optimal, but comprehensive consideration of DXC and OEP resources within the node is not necessarily optimal, and will bring waste of resources such as DXC and OEP to a certain extent. In view of the problem that resources such as DXC and OEP are not considered in the calculation of the route in the related art, DXC, OEP, and the like are wasted, and no effective solution has been proposed yet. SUMMARY OF THE INVENTION The present invention provides a route calculation method and apparatus to solve at least one of the above problems. According to an aspect of the present invention, a route calculation method is provided, including: splitting each network element node in an optical transport network (OTN) into a plurality of network element sub-nodes; configuring child nodes for multiple network element sub-nodes Linking, and constructing extended topology information of multiple network element sub-nodes according to the child node link; performing route calculation on multiple network element child nodes according to the extended topology information. Preferably, the network element node includes: a service head node, a service tail node, and a service intermediate node. Preferably, each network node in the optical transport network (OTN) is split into a plurality of network element sub-nodes, including: when the network element node is the service first node, according to the number of the first link port of the service head node and the first A client port splits the service head node into M+1 first network element child nodes, and uses the first network element child node split according to the first client port as the service first child node, where the first link The number of ports is M. Preferably, configuring the child node link for the multiple network element sub-nodes includes: using the first link between the service head node and the other network element node as the first external link of the first network element child node, and The link cost of the first link is the first external link cost of the first external link; the first internal link is configured between the first network element sub-nodes, and the wavelength exchange is performed according to the first network element sub-node or The first resource required for wavelength conversion consumes the first internal link cost of configuring the first internal link. Preferably, each network node in the optical transmission network (OTN) is split into a plurality of network element sub-nodes, including: when the network element node is a service tail node, according to the number of second link ports of the service tail node and the number The second client port splits the service tail node into N+1 second network element sub-nodes, and uses the second network element sub-node split according to the second client port as the service tail node, where the second link The number of ports is N. Preferably, configuring the child node link for the multiple network element sub-nodes includes: using the second link between the service tail node and the other network element node as the second external link of the second network element sub-node, and The link cost of the second link is the second external link cost of the second external link; the second internal link is configured between the second network element sub-nodes, and the wavelength exchange is performed according to the second network element sub-node or The second resource required for wavelength conversion consumes the second internal link cost of the second internal link. Preferably, each network node in the optical transport network (OTN) is split into a plurality of network element sub-nodes, including: when the network element node is a service intermediate node, the service is performed according to the third link port number of the service intermediate node. The intermediate node is split into P third network element sub-nodes, wherein the third link port number is P. Preferably, configuring the child node link for the multiple network element sub-nodes includes: using the third link between the service intermediate node and the other network element node as the third external link of the third network element sub-node, and The link cost of the third link is the third external link cost of the third external link; the third internal link is configured between the third network element sub-nodes, and the wavelength exchange is performed according to the third network element sub-node or The third resource required for wavelength conversion consumes the third internal link cost of the third internal link. Preferably, constructing extended topology information of the multiple network element sub-nodes according to the sub-node link includes: according to the first external link and the first external link cost, the first internal link, and the first internal link cost, Two external link and second outer link cost, second internal link and second internal link cost, third external link and third external link cost, and third internal link and third internal link cost The extended topology information of multiple network element sub-nodes is jointly constructed as a child node link. Preferably, the routing calculation is performed on the plurality of network element sub-nodes according to the extended topology information, including: adopting a Constrained Shortest Path First (CSPF) algorithm, and performing routing calculation on the plurality of network element sub-nodes according to the extended topology information. According to another aspect of the present invention, a routing computing apparatus is provided, including: a splitting module, configured to split each network element node in an optical transport network (OTN) into a plurality of network element sub-nodes; The configuration module is configured to configure a child node link for multiple network element sub-nodes; the building module is configured to construct extended topology information of multiple network element sub-nodes according to the child node link; and the computing module is set to multiple networks according to the extended topology information. The meta-node performs route calculation. Preferably, the network element node includes: a service head node, a service tail node, and a service intermediate node. According to the present invention, the method for splitting each network element into a plurality of network element sub-nodes and then constructing the extended topology of the plurality of network element sub-nodes solves the problem that the existing route calculation method does not consider the DXC inside the network element. Resources such as OEP cause waste of resources such as DXC and OEP, thereby achieving the effects of saving resources such as DXC and OEP, improving the effective use rate of OXC resources, and reducing service consumption. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1 is a schematic diagram of a typical OTN network element structure according to the related art; FIG. 2 is a topological schematic diagram of an OTN network composed of OTN network elements according to the related art; 3 is a flowchart of a route calculation method according to an embodiment of the present invention; FIG. 4 is a flowchart of a route calculation method according to a preferred embodiment of the present invention; FIG. 5 is a schematic structural diagram of an extended topology example 1 constructed according to a preferred embodiment of the present invention; 6 is a block diagram showing an example of an extended topology example 2 constructed in accordance with a preferred embodiment of the present invention; and FIG. 7 is a block diagram showing the structure of a route calculation device according to an embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. FIG. 3 is a flowchart of a route calculation method according to an embodiment of the present invention. As shown in FIG. 3, the method mainly includes the following steps (step S302-step S306): Step S302, each network element in an optical transport network (OTN) The node is split into a plurality of network element sub-nodes; Step S304, configuring a child node link for the plurality of network element child nodes, and constructing extended topology information of the plurality of network element child nodes according to the child node link; Step S306, according to the extension The topology information performs route calculation on multiple network element sub-nodes. In this embodiment, the network element node may include: a service first node, a service tail node, and a service intermediate node. In this embodiment, step S302 can be implemented in three different situations:

(1) When the network element node is the service first node, the service first node is split into M+1 first network element sub-nodes according to the first link port number of the service head node and the first client port, and The first network element sub-node split by the first client port is used as the service first child node, where the number of the first link port is M. (2) When the network element node is a service tail node, the service tail node is split into N+1 second network element sub-nodes according to the second link port number of the service tail node and the second client port, and The second network element sub-node split by the second client port is used as the service tail node, and the number of the second link port is N.

(3) When the network element node is a service intermediate node, the service intermediate node is split into P third network element sub-nodes according to the number of the third link port of the service intermediate node, where the number of the third link port is P . After the above three network element nodes are split into different network element sub-nodes, the child node can be configured for the network element sub-nodes obtained by the above three different situations, and the specific implementation can be implemented as follows:

(1) When the network element node is the service first node, configuring the child node link for the first network element child node includes: using the first link between the service head node and other network element nodes as the first network element child node a first external link, and using a link cost of the first link as a first external link cost of the first external link; configuring a first internal link between the first network element sub-nodes, and according to the The first resource cost required for wavelength switching or wavelength conversion of a network element sub-node configures a first internal link cost of the first internal link.

(2) When the network element node is the service tail node, configuring the child node link for the second network element child node includes: using the second link between the service tail node and the other network element node as the second network element child node a second external link, and a link cost of the second link as a second external link cost of the second external link; configuring a second internal link between the second network element sub-nodes, and according to the The second resource cost required for the two network element sub-nodes to perform wavelength switching or wavelength conversion configures the second internal link cost of the second internal link.

(3) When the network element node is a service intermediate node, configuring the child node link for the third network element child node includes: using the third link between the service intermediate node and the other network element node as the third network element child node a third external link, and a link cost of the third link as a third external link cost of the third external link; configuring a third internal link between the third network element sub-nodes, and according to the The third resource cost required for the three-network sub-node to perform wavelength switching or wavelength conversion configures the third internal link cost of the third internal link. In this embodiment, after configuring the child node link for the three different network element sub-nodes (the first network element child node, the second network element child node, and the third network element child node), the child node may be configured according to the child node. The link constructs extended topology information of the multiple network element sub-nodes, including: according to the first external link and the first external link cost, the first internal link and the first internal link cost, the second external link, and the first Two external link costs, a second internal link and a second internal link cost, a third external link and a third external link cost, and a third internal link and a third internal link cost together as a child node link Construct extended topology information of multiple network element sub-nodes. At this point, step S304 is performed, and then the constrained shortest path first CSPF algorithm is used to perform route calculation on multiple network element sub-nodes according to the extended topology information. In this embodiment, when performing route calculation on multiple network element sub-nodes according to the extended topology information, the method may be implemented in the following manner: using a Constrained Shortest Path First (CSPF) algorithm, and multiple network elements according to extended topology information. The node performs route calculation. The above route calculation method will be described in detail below with reference to FIGS. 4 to 6 and a preferred embodiment. 4 is a flowchart of a route calculation method according to a preferred embodiment of the present invention. As shown in FIG. 4, the process mainly includes the following steps (step S402-step S412): Step S402, pressing each network element node according to its link port. Splitting into a plurality of child nodes; Step S404, converting the link between the nodes into an external link between the child nodes, the link cost is unchanged; Step S406, setting an internal chain between the child nodes inside the node And configuring the cost of the link based on the resource consumption required for wavelength switching between the child nodes; Step S408, for the service head and tail node, according to the service access port (that is, the first client port or the second client port) Each of the sub-nodes is split and a new first-to-end node is calculated as a route; in step S410, an internal link between the sub-nodes associated with the egress-way port and the sub-nodes associated with the link port is set inside the service end-to-end node, And configuring the cost of the link based on the resource consumption required for the uplink and the egress between the child nodes; Step S412, the link between the child node and the child node Based on the extended topology of all the child nodes, the Constrained Shortest Path First (CSPF) algorithm is used to perform route calculation. The route calculation method shown in FIG. 4 will be further described below with reference to FIG. 5. Please refer to FIG. 5. FIG. 5 is a schematic structural diagram of an extended topology example 1 constructed according to a preferred embodiment of the present invention. When the extended topology shown in FIG. 5 is adopted, the method shown in FIG. 4 can be implemented as follows:

(1) Split each network element node into several child nodes according to its link port. Specifically, node A has two links AB and AC, and is split into child nodes A1 and A2; node B has two links AB and BD, and is split into child nodes Bl and B2;

(2) The link between the nodes is converted into an external link between the child nodes, and the link cost is unchanged. Specifically, the link AB between the nodes is converted into the external link A1B1 between the child nodes, and the link cost is 10; the link AC between the nodes is converted into the external link A2C1 between the child nodes, the link cost Is 10;

(3) Inside the node, the internal link between the child nodes is set, and the cost of the link is configured based on the resource consumption required for wavelength switching between the child nodes. Specifically, for the nodes A, C, and D, the child nodes A1 and A2, CI and C2, and the common available wavelengths between D1 and D2 can be directly exchanged by OXC, and then configured based on the resource consumption of the OXC. The cost of the link is set to 1 for the link cost; for Node B, there is no common available wavelength between the sub-nodes B1 and B2, but it can be accessed through resources such as DXC and OEP. For the wavelength switching or wavelength conversion, the cost of configuring the link is based on the resource consumption of OXC, DXC, and OEP, and the link cost is configured to be 100;

(4) For the first and last nodes of the service, one sub-node is split according to the service port, and a new first-to-end node is calculated as the route. Specifically, the first and last nodes of the service are nodes A and D, respectively, and the child nodes A0 and DO are split. (5) Inside the service head and tail nodes, the child nodes related to the uplink and the downlink ports are set between the child nodes related to the link ports. The internal link, and the cost of configuring the link based on the resource consumption required for the uplink and the egress between the child nodes. Specifically, if the port is directly connected to the OXC, the cost of the link is configured based on the resource consumption of the OXC; if the port is connected to the OXC through resources such as DXC and OEP, the OXC, DXC, and OEP are used. Based on the resource consumption, configure the cost of the link; if the child node A0 is directly connected to the OXC, the cost of the link A0A1 is set to 1;

(6) Based on the link between the child node and the child node, form an extended topology, and call the CSPF (Constrained Shortest Path First) algorithm for route calculation. Specifically, the route calculation based on the original topology, the total cost of the path only includes the total cost of the WDM link, and does not take into account the cost of resource consumption such as DXC and OEP within the node. If the internal resource consumption of the node is considered, the actual total cost will be increase. Based on the extended topology for route calculation, the total cost of the path includes not only the total cost of the WDM link, but also the cost of resource consumption such as DXC and OEP within the node. Since the extended topology integrates WDM links, OXC, DXC, OEP and other resources, The routing calculation results are optimized. Please refer to Table 1. Table 1. Results chart of route calculation based on original topology and extended topology example

The route calculation method shown in FIG. 4 will be further described below with reference to FIG. Please refer to FIG. 6. FIG. 6 is a schematic structural diagram of an extended topology example 2 constructed according to a preferred embodiment of the present invention. When the extended topology shown in FIG. 6 is adopted, the method shown in FIG. 4 can be implemented as follows: (1) Split each network element node into several child nodes according to its link port. Specifically, the node A has two links AB and AC, and is split into child nodes A1 and A2; the node B has two links AB and BD, and is split into child nodes B1 and B2;

(3) Inside the node, the internal link between the child nodes is set, and the cost of the link is configured based on the resource consumption required for wavelength switching between the child nodes. Specifically, for the nodes A, C, and D, the child nodes A1 and A2, CI and C2, and the common available wavelengths between D1 and D2 can be directly exchanged by OXC, and then configured based on the resource consumption of the OXC. The cost of the link is set to 1 for the link cost. If the node sub-nodes B1 and B2 cannot perform wavelength switching or wavelength conversion through resources such as DXC and OEP, the link is unavailable, and the cost of the link is configured as +∞;

(6) Based on the link between the child node and the child node, form an extended topology, and call the CSPF (Constrained Shortest Path First) algorithm for route calculation. Specifically, since the original topology is mainly composed of a WDM link and an OXC, the route calculation will obtain an invalid result for the case where the wavelength conversion cannot be performed between the links. Based on the extended topology for routing calculation, not only the WDM link and OXC resources are considered, but also the wavelength conversion between the internal links of the nodes through DXC and OEP is considered, and effective results can be obtained. Please refer to Table 2. Table 2, the result graph of the route calculation based on the original topology and the extended topology example Route shortest path Actual shortest path (including the actual total path point internal resource consumption) Cost (including whether the result node is valid

Department resources

Consumption)

Based on A-B-D A0-A1-B1-B2-D1-D0 20 Invalid Original

Topology Based on A0-A2-C1-C2-D2-D0 A0-A2-C1-C2-D2-D0 33 33 Effective Extension

The topology needs to be explained. The main difference between the extended topology 1 and the extended topology 2 is: In the extended topology example 1, the two sub-nodes of the node B can perform wavelength switching or wavelength conversion through resources such as DXC and OEP, and between the child nodes. The link is available. In the extended topology example 2, the two sub-nodes of the node B cannot perform wavelength switching or wavelength conversion through resources such as DXC and OEP, and the link between the child nodes is unavailable. Both of these situations can be considered in routing calculations by building an extended topology. According to the route calculation method provided in the foregoing embodiment, each network element node is first split into multiple network element sub-nodes, and then the expansion topology of multiple network element sub-nodes is constructed, which can solve the existing route calculation method without considering the internal network element. The resources such as DXC and OEP cause waste of resources such as DXC and OEP, thereby achieving the effects of saving resources such as DXC and OEP, improving the effective use rate of OXC resources, and reducing service consumption. FIG. 7 is a structural block diagram of a route calculation device according to an embodiment of the present invention. The device is used to implement the route calculation method provided by the foregoing embodiment. As shown in FIG. 7, the device mainly includes: a split module 10, a configuration module 20, The module 30 and the calculation module 40 are constructed. The splitting module 10 is configured to split each network element node in the optical transport network OTN into multiple network element sub-nodes; the configuration module 20 is connected to the splitting module 10, and is configured as multiple network element sub-nodes. Configuring a child node link; a building module 30, connected to the configuration module 20, configured to construct extended topology information of the plurality of network element sub-nodes according to the child node link; the computing module 40, connected to the building module 30, configured to be based on the extended topology The information is routed to multiple network element sub-nodes. In this embodiment, the network element node may include: a service first node, a service tail node, and a service intermediate node. The routing calculation device provided by the foregoing embodiment first splits each network element node into multiple network element sub-nodes, and then constructs an expansion topology of multiple network element sub-nodes, which can solve the existing route calculation method without considering the internal network element. The resources such as DXC and OEP cause waste of resources such as DXC and OEP, thereby achieving the effects of saving resources such as DXC and OEP, improving the effective use rate of OXC resources, and reducing service consumption. From the above description, it can be seen that the present invention achieves the following technical effects: The method for splitting each network element node into multiple network element sub-nodes and then constructing the expansion topology of multiple network element sub-nodes is solved. The existing route calculation method does not consider the resources such as DXC and OEP in the network element, which causes waste of resources such as DXC and OEP, thereby saving resources such as DXC and OEP, improving the effective use rate of OXC resources, and reducing service consumption. effect. Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

1. A route calculation method, comprising:

Splitting each network element node in the optical transport network OTN into a plurality of network element sub-nodes; configuring a child node link for the plurality of network element child nodes, and constructing the multiple network according to the child node link Extended topology information of the meta-node;

Performing route calculation on the plurality of network element sub-nodes according to the extended topology information.

The method according to claim 1, wherein the network element node comprises: a service head node, a service tail node, and a service intermediate node.

The method according to claim 2, wherein splitting each network node in the optical transport network OTN into multiple network element sub-nodes includes:

When the network element node is the service first node, the service first node is split into M+1 first network element sub-nodes according to the first link port number of the service head node and the first client port. And the first network element sub-node that is split according to the first client port is used as the service first child node, where the number of the first link port is M.

The method according to claim 3, wherein configuring the child node link for the plurality of network element sub-nodes comprises:

Using the first link between the service head node and the other network element node as the first external link of the first network element child node, and using the link cost of the first link as a Describe a first external link cost of the first external link;

Configuring a first internal link between the first network element sub-nodes, and configuring the first internal link according to a first resource cost required for wavelength switching or wavelength conversion of the first network element sub-node The first internal link cost.

The method according to claim 4, wherein splitting each network node in the optical transport network OTN into multiple network element sub-nodes includes:

When the network element node is a service tail node, the service tail node is split into N+1 second network element sub-nodes according to the second link port number of the service tail node and the second client port. And the second network element sub-node that is split according to the second client port is used as a service tail node, where the number of the second link port is N.

The method according to claim 5, wherein configuring the child node link for the multiple network element sub-nodes includes:

Using a second link between the service tail node and the other network element node as a second external link of the second network element sub-node, and using the link cost of the second link as a Describe a second external link cost of the second external link;

Configuring a second internal link between the second network element sub-nodes, and configuring the second internal link according to the second resource consumption required for performing wavelength switching or wavelength conversion on the second network element sub-node Second internal link cost.

The method according to claim 6, wherein splitting each network node in the optical transport network OTN into multiple network element sub-nodes includes:

When the network element node is a service intermediate node, the service intermediate node is split into P third network element sub-nodes according to the third link port number of the service intermediate node, where the third chain The number of port ports is P.

8. The method according to claim 7, wherein configuring the child node link for the plurality of network element sub-nodes comprises:

Using a third link between the service intermediate node and the other network element node as a third external link of the third network element sub-node, and using the link cost of the third link as a Describe a third external link cost of the third external link;

Configuring a third internal link between the third network element sub-nodes, and configuring the third internal link according to the third resource consumption required for performing wavelength switching or wavelength conversion on the third network element sub-node Third internal link cost.

9. The method according to claim 8, wherein the extended topology information of the plurality of network element sub-nodes is constructed according to the child node link, including: according to the first external link and the first external Link cost, the first internal link and the first internal link cost, the second external link and the second external link cost, the second internal link, and the second An internal link cost, a third external link and the third external link cost, and the third internal link and the third internal link cost together as the child node link to construct the plurality of networks Extended topology information of the meta-node. The method according to any one of claims 1 to 8, wherein performing routing calculation on the plurality of network element sub-nodes according to the extended topology information comprises: The constrained shortest path first CSPF algorithm is used to perform route calculation on the plurality of network element subnodes according to the extended topology information.

11. A routing computing device, comprising:

The splitting module is configured to split each network element node in the optical transport network OTN into multiple network element sub-nodes;

a configuration module, configured to configure a child node link for the multiple network element sub-nodes;

a building module, configured to construct extended topology information of the plurality of network element sub-nodes according to the child node link;

And a calculation module, configured to perform route calculation on the plurality of network element sub-nodes according to the extended topology information.

The device according to claim 11, wherein the network element node comprises: a service head node, a service tail node, and a service intermediate node.