CN106603405B

CN106603405B - Routing and wavelength allocation method and device

Info

Publication number: CN106603405B
Application number: CN201510666794.XA
Authority: CN
Inventors: 王大伟; 哈米德·麦赫瓦
Original assignee: Huawei Technologies Co Ltd
Current assignee: Honor Device Co Ltd
Priority date: 2015-10-15
Filing date: 2015-10-15
Publication date: 2020-02-14
Anticipated expiration: 2035-10-15
Also published as: CN106603405A; WO2017063486A1

Abstract

The application discloses a routing and wavelength allocation method and device. After receiving a connection request, a network controller acquires N wavelength groups, and acquires candidate path sets corresponding to the N wavelength groups according to information of a transmitting end node and a receiving end node contained in the connection request; then, obtaining a weight calculation parameter of a candidate path in the candidate path set, calculating a weight value of the candidate path according to the weight calculation parameter of the candidate path, and determining a path and a wavelength used by the connection request according to the weight value of the candidate path and a wavelength group corresponding to the candidate path set. At least one parameter in the weight calculation parameters of one candidate path is obtained by calculation according to the characteristic parameters of the optical cross nodes on the candidate path, so that the routing and wavelength allocation can be carried out on the basis of the physical and/or optical characteristics of the optical cross nodes on the candidate path, and the reasonability of the routing and wavelength allocation is improved.

Description

Routing and wavelength allocation method and device

Technical Field

The present invention relates to the field of communications, and in particular, to a method and an apparatus for allocating routes and wavelengths.

Background

An optical network refers to a communication network using light as a transmission medium, and the transmission medium is an optical fiber.

Wavelength Division Multiplexing (WDM) technology and Dense Wavelength Division Multiplexing (DWDM) technology are applied to an optical network, and are technologies for simultaneously transmitting multi-Wavelength optical signals in one optical fiber. The basic principle is that optical signals with different wavelengths are multiplexed at a transmitting end node and coupled to the same optical fiber on an optical cable line for transmission, and the optical signals with the combined wavelengths are demultiplexed at a receiving end node, and the original signals are restored and then sent to different terminals.

The WDM optical network or DWDM optical network includes a plurality of optical cross nodes, which may be networked in various forms. The transmitting end node and the receiving end node communicate through an optical network. Multiple paths (one path includes multiple optical cross nodes) usually exist between the sending end node and the receiving end node, one path can be selected between the sending end node and the receiving end node according to a certain rule, and after the path is selected, a certain idle wavelength is selected for communication according to a certain rule. This process is called routing and wavelength assignment.

An existing routing and wavelength allocation method is as follows: after receiving a connection request, calculating a shortest path between a sending end node and a receiving end node, calculating an idle wavelength set which meets wavelength continuity on the shortest path, selecting a first wavelength from the set, calculating a Four-Wave Mixing (FWM) noise sum on all links passed by the wavelength, if the FWM noise sum is smaller than a FWM threshold value, selecting the shortest path and the wavelength for the connection request, and otherwise, blocking the connection request. Wherein the FWM noise belongs to a link characteristic parameter.

As the optical network topology becomes increasingly Mesh (Mesh means that the network topology is dynamically expandable), the influence of the characteristics of the optical cross node on the routing and wavelength allocation gradually appears.

Therefore, in the prior art, the link characteristic parameters are used as the basis for wavelength allocation, which results in the lack of rationality of routing and wavelength allocation, and further affects the transmission performance.

Disclosure of Invention

The application provides a routing and wavelength allocation method and device, which are used for improving the reasonability of routing and wavelength allocation.

In a first aspect, a method for allocating routes and wavelengths is provided, including:

receiving a connection request, wherein the connection request comprises information of a transmitting end node and a receiving end node;

acquiring N wavelength groups, and acquiring candidate path sets corresponding to the N wavelength groups according to the sending end node and the receiving end node, wherein N is an integer greater than or equal to 1, and one wavelength group comprises 1 or more wavelengths;

acquiring weight calculation parameters of candidate paths in the candidate path set, wherein at least one of the weight calculation parameters of one candidate path is obtained by calculation according to the characteristic parameter of the optical cross node on the candidate path;

calculating a weight value of the candidate path according to the weight calculation parameter of the candidate path;

and determining the path and the wavelength used by the connection request according to the weight value of the candidate path and the wavelength group corresponding to the candidate path set.

With reference to the first aspect, in a first possible implementation manner of the first aspect, if one wavelength group includes one wavelength, the number of links that have used the wavelength is less than the total number of links; alternatively, if a plurality of wavelengths are included in one wavelength set, the number of links that have used the plurality of wavelengths is less than the total number of links.

With reference to the first aspect or the first possible implementation manner of the first aspect, in a second possible implementation manner of the first aspect, if a wavelength group includes a wavelength, a candidate path corresponding to the wavelength group meets a wavelength continuity requirement; if a wavelength group includes a plurality of wavelengths, one of the plurality of wavelengths is allowed to be converted to another of the plurality of wavelengths at an optical cross node where a wavelength converter is disposed in a candidate path corresponding to the wavelength group and/or at a wavelength converter disposed in an optical fiber link of the candidate path.

With reference to the first aspect or any one of the first to the second possible implementation manners of the first aspect, in a third possible implementation manner of the first aspect, the characteristic parameter of the optical cross node includes one or a combination of the following parameters:

an instantaneous blocking probability for representing the probability corresponding to the number of wavelengths existing in the optical cross node; wherein, the probability corresponding to the number of the existing wavelengths represents: the probability that the next connection request is blocked by the optical cross-node at the number of wavelengths present;

a crosstalk parameter for indicating a magnitude of interference corresponding to a number of wavelengths existing in the optical cross node; wherein, the interference size corresponding to the number of the existing wavelengths represents: the optical cross node is under the condition of the number of the existing wavelengths, and the wavelength allocated by the next connection request is subjected to the interference value from the corresponding number of the existing wavelengths in the optical cross node;

a power loss parameter representing an insertion loss value of the optical cross node;

a polarization dependent loss parameter.

With reference to the third possible implementation manner of the first aspect, in a fourth possible implementation manner of the first aspect, the obtaining process of the instant blocking probability of the optical cross node includes: acquiring configuration information of an optical cross node, wherein the configuration information at least comprises the number of existing wavelengths in the optical cross node; and inquiring the corresponding relation between the number of the wavelengths and the instant blocking probability according to the number of the existing wavelengths in the optical cross node to obtain the instant blocking probability corresponding to the number of the existing wavelengths in the optical cross node.

With reference to the third possible implementation manner of the first aspect, in a fifth possible implementation manner of the first aspect, the obtaining process of the crosstalk parameter of the optical cross node includes: acquiring configuration information of an optical cross node, wherein the configuration information at least comprises the number of existing wavelengths in the optical cross node; and inquiring the corresponding relation between the number of the wavelengths and the crosstalk parameters according to the number of the existing wavelengths in the optical cross node to obtain the crosstalk parameters corresponding to the number of the existing wavelengths in the optical cross node.

With reference to the first aspect or any one of the first to fifth possible implementation manners of the first aspect, in a sixth possible implementation manner of the first aspect, the weight calculation parameter further includes: a link characteristic parameter;

the link characteristic parameters of a path include one or a combination of the following parameters:

the wavelength utilization rate is used for expressing the ratio of the number of the used wavelengths on one path to the number of all the available wavelengths on the path;

a power loss parameter representing an insertion loss value of a path;

a link cost parameter for indicating a service cost size of a path;

and the link delay parameter is used for indicating the delay size of one path.

With reference to the first aspect or the first to sixth possible implementation manners of the first aspect, in a seventh possible implementation manner of the first aspect, the calculating a weight value of the candidate path according to the weight calculation parameter of the candidate path includes:

calculating the weight value of the candidate path according to the following formula:

wherein cost represents the weight value of a candidate path, N represents the number of weight calculation parameters corresponding to the candidate path, N is an integer greater than or equal to 1, and P_iα, the ith weight calculation parameter of the N weight calculation parameters corresponding to the candidate path_iRepresents P_iA corresponding weight value; wherein at least one of the N weight calculation parameters is an accumulated sum of characteristic parameters of the optical cross node on the candidate path or an average value of the accumulated sum.

With reference to the seventh possible implementation manner of the first aspect, in an eighth possible implementation manner of the first aspect, before calculating a weight value of a candidate path, the method further includes: and determining a weight value corresponding to the weight calculation parameter of the candidate path according to the service level corresponding to the connection request.

With reference to the first aspect or the first to eighth possible implementation manners of the first aspect, in a ninth possible implementation manner of the first aspect, the determining, according to the weight value of the candidate path and the wavelength group corresponding to the candidate path set to which the candidate path set belongs, a path and a wavelength used by the connection request includes:

selecting a candidate path with the minimum weight value according to the weight value of the candidate path;

and determining the selected candidate path with the minimum weight value as the path used by the connection request, and determining the wavelength in the wavelength group corresponding to the candidate path set to which the candidate path with the minimum weight value belongs as the wavelength used by the connection request.

In a second aspect, a routing and wavelength allocation apparatus is provided, which includes:

a receiving unit, configured to receive a connection request, where the connection request includes information of a sender node and a receiver node;

a first obtaining unit, configured to obtain N wavelength groups, and obtain, according to the sending end node and the receiving end node, candidate path sets corresponding to the N wavelength groups, where N is an integer greater than or equal to 1, and one wavelength group includes 1 or multiple wavelengths;

a second obtaining unit, configured to obtain weight calculation parameters of candidate paths in the candidate path set, where at least one of the weight calculation parameters of a candidate path is calculated according to a characteristic parameter of an optical cross node on the candidate path;

the calculating unit is used for calculating parameters according to the weight of the candidate paths and calculating the weight values of the candidate paths;

and the determining unit is used for determining the path and the wavelength used by the connection request according to the weight value of the candidate path and the wavelength group corresponding to the candidate path set.

With reference to the second aspect, in a first possible implementation manner of the second aspect, if a wavelength is included in a wavelength group, the number of links that have used the wavelength is less than the total number of links; alternatively, if a plurality of wavelengths are included in one wavelength set, the number of links that have used the plurality of wavelengths is less than the total number of links.

With reference to the second aspect or the first possible implementation manner of the second aspect, in a second possible implementation manner of the second aspect, if a wavelength group includes a wavelength, a candidate path corresponding to the wavelength group meets a wavelength continuity requirement; if a wavelength group includes a plurality of wavelengths, one of the plurality of wavelengths is allowed to be converted to another of the plurality of wavelengths at an optical cross node where a wavelength converter is disposed in a candidate path corresponding to the wavelength group and/or at a wavelength converter disposed in an optical fiber link of the candidate path.

With reference to the second aspect or any one of the first to the second possible implementation manners of the second aspect, in a third possible implementation manner of the second aspect, the characteristic parameter of the optical cross node includes one or a combination of the following parameters:

a polarization dependent loss parameter.

With reference to the third possible implementation manner of the second aspect, in a fourth possible implementation manner of the second aspect, the second obtaining unit is specifically configured to: in the process of obtaining the instant blocking probability of the optical cross node, the following steps are executed: acquiring configuration information of an optical cross node, wherein the configuration information at least comprises the number of existing wavelengths in the optical cross node; and inquiring the corresponding relation between the number of the wavelengths and the instant blocking probability according to the number of the existing wavelengths in the optical cross node to obtain the instant blocking probability corresponding to the number of the existing wavelengths in the optical cross node.

With reference to the third possible implementation manner of the second aspect, in a fifth possible implementation manner of the second aspect, the second obtaining unit is specifically configured to: in the process of obtaining crosstalk parameters of the optical cross node, the following steps are executed: acquiring configuration information of an optical cross node, wherein the configuration information at least comprises the number of existing wavelengths in the optical cross node; and inquiring the corresponding relation between the number of the wavelengths and the crosstalk parameters according to the number of the existing wavelengths in the optical cross node to obtain the crosstalk parameters corresponding to the number of the existing wavelengths in the optical cross node.

With reference to the second aspect or any one of the first to fifth possible implementation manners of the second aspect, in a sixth possible implementation manner of the second aspect, the weight calculation parameter further includes: a link characteristic parameter;

a power loss parameter representing an insertion loss value of a path;

a link cost parameter for indicating a service cost size of a path;

and the link delay parameter is used for indicating the delay size of one path.

With reference to the second aspect or any one of the first to sixth possible implementation manners of the second aspect, in a seventh possible implementation manner of the second aspect, the calculating unit is specifically configured to:

With reference to the seventh possible implementation manner of the second aspect, in an eighth possible implementation manner of the second aspect, the calculating unit is further configured to: before calculating the weight value of a candidate path, determining the weight value corresponding to the weight calculation parameter of the candidate path according to the service level corresponding to the connection request.

With reference to the second aspect or the first to eighth possible implementation manners of the second aspect, in a ninth possible implementation manner of the second aspect, the determining unit is specifically configured to:

In a third aspect, a routing and wavelength allocation apparatus is provided, which may include: an interface, a processing unit, and a memory. The processing unit is used for controlling the operation of the device; the memories may include both read-only memories and random access memories for providing instructions and data to the processing unit. The portion of memory may also include non-volatile row random access memory (NVRAM). The various components of the device are coupled together by a bus system that includes a power bus, a control bus, and a status signal bus in addition to a data bus.

The routing and wavelength allocation procedure provided in any implementation manner of the foregoing first aspect or the first aspect may be applied to or implemented by a processing unit. In the implementation process, the steps of the routing and wavelength allocation flow implemented by the apparatus may be implemented by an integrated logic circuit of hardware in the processing unit or instructions in the form of software. The processing unit may be a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any other means for implementing or executing the methods, steps, and logic blocks disclosed in the first aspect or any implementation manner of the first aspect. A general purpose processor may be a microprocessor or any conventional processor or the like. The steps of the method disclosed in connection with the first aspect or any implementation manner of the first aspect may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in a processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is arranged in the memory, and the processing unit reads the information in the memory and completes the steps of routing and wavelength allocation flow by combining the hardware.

In particular, the processing unit may be configured to perform the routing and wavelength allocation procedure described in the first aspect or any implementation manner of the first aspect.

A fourth aspect provides a storage medium having computer program instructions embodied therein, where the computer program instructions are operable to implement the routing and wavelength allocation procedure described in the first aspect or any one of the possible implementation manners of the first aspect. The storage medium includes, but is not limited to, disk storage, CD-ROM, optical storage, etc., or a form of computer program product embodied on disk storage, CD-ROM, optical storage, etc.

In the above embodiment of the present invention, after receiving the connection request, N wavelength sets are obtained, and candidate path sets corresponding to the N wavelength sets are obtained according to the information of the sender node and the receiver node included in the connection request; then, obtaining a weight calculation parameter of a candidate path in the candidate path set, calculating a weight value of the candidate path according to the weight calculation parameter of the candidate path, and determining a path and a wavelength used by the connection request according to the weight value of the candidate path and a wavelength group corresponding to the candidate path set. At least one parameter in the weight calculation parameters of one candidate path is obtained by calculation according to the characteristic parameters of the optical cross nodes on the candidate path, so that the routing and wavelength allocation can be carried out on the basis of the physical and/or optical characteristics of the optical cross nodes on the candidate path, and the reasonability of the routing and wavelength allocation is improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic diagram of an optical cross-point node in the prior art;

FIG. 2 is a schematic diagram of a prior art WDM optical network architecture;

fig. 3 is a schematic diagram illustrating a routing and wavelength allocation process according to an embodiment of the present invention;

FIG. 4 is a schematic view of a wavelength layer topology corresponding to a wavelength 1 according to an embodiment of the present invention;

FIG. 5 is a schematic view of a wavelength layer topology corresponding to wavelength 2 in an embodiment of the present invention;

FIG. 6 is a schematic diagram of signal crosstalk during optical crossing according to an embodiment of the present invention;

fig. 7 is a schematic diagram of OSNR penalty due to signal crosstalk in the optical cross-connection process in the embodiment of the present invention;

FIG. 8 is a diagram illustrating polarization multiplexing during an optical interleaving process according to an embodiment of the present invention;

FIG. 9 is a second schematic diagram of polarization multiplexing during the optical cross-over process according to the embodiment of the present invention;

FIG. 10 is a schematic diagram of OSNR penalty due to signal polarization dependent loss during optical crossing according to an embodiment of the present invention;

fig. 11 is a second schematic diagram illustrating a routing and wavelength allocation process according to an embodiment of the present invention;

fig. 12 is a schematic structural diagram of a routing and wavelength allocation apparatus according to an embodiment of the present invention;

fig. 13 is a second schematic structural diagram of a routing and wavelength allocation apparatus according to an embodiment of the present invention.

Detailed Description

The WDM optical network or DWDM optical network includes a plurality of optical cross nodes, and the optical cross nodes have a plurality of networking modes, such as a ring network, a tree network, a star network, a Mesh network, and the like. These optical cross-Connect nodes may be optical cross-Connect (OXC) devices, or other devices capable of optical switching.

As shown in fig. 1, the optical cross node is mainly composed of several major parts, i.e., an input part (amplifier EDPA, demultiplexing DMUX), an optical cross-connect part (optical cross-connect matrix), an output part (wavelength converter OTU, multiplexer MUX), a control and management part, and so on. The wavelength converters are optionally configured, for example, no wavelength converter or one or more wavelength converters may be configured in the optical cross-over node. The wavelength converter may convert the optical signal from one wavelength to another wavelength. If the wavelength converter is not arranged in the optical cross node, the optical signals before and after the optical cross node cross meet the wavelength consistency principle, namely the wavelength before the optical signal cross is consistent with the wavelength after the optical signal cross.

Fig. 2 exemplarily shows a WDM optical network architecture in which a numbered circle represents an optical cross-over node, a non-numbered circle represents a relay node, and a square represents an access node (such as a transmitter node or a receiver node). The links between the optical cross-nodes are WDM links.

As shown in fig. 2, any two access points may use one or more wavelengths to connect with each other, and there are multiple alternative paths between the two access points. That is, the route between two access points may pass through a plurality of optical fiber links and a plurality of optical cross nodes, and may use one wavelength (for example, in the case where a wavelength converter is not provided in an optical cross node and a wavelength converter is not provided on an optical fiber link) or a plurality of wavelengths (for example, in the case where a wavelength converter is provided in an optical cross node or a wavelength converter is provided on an optical fiber link).

For example, in fig. 2, the communication between access point a to access point B may be selected from a plurality of candidate paths, which may include: 2- >1- >8- >9- >13, 2- >4- >5- >7- >8- >9- >13, 2- >4- >11- >13, and the like. In routing, the prior art adopts a shortest path selection method, for example, to select a path with the least number of hops (the number of hops of one path is equal to the number of optical cross nodes on the path minus 1) from multiple candidate paths, or to select a path with the least number of relay nodes to pass through.

As network topologies become increasingly Mesh, the influence of the characteristics of optical cross nodes on routing and wavelength allocation gradually appears. In this case, routing and wavelength allocation in the optical network need to take the characteristics of the optical cross-nodes into account to ensure that the signal can both meet the path transmission requirements and select the principle of minimum quality loss.

In order to improve the rationality of routing and wavelength allocation, embodiments of the present invention provide a routing and wavelength allocation scheme, in which a parameter capable of reflecting physical and/or optical characteristics of an optical cross node is introduced as a calculation basis in a routing and wavelength allocation process, so that routing and wavelength allocation can be performed based on the physical and/or optical characteristics of the optical cross node on a candidate path, thereby improving the rationality of routing and wavelength allocation.

In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 3, a schematic diagram of a routing and wavelength allocation process according to an embodiment of the present invention is provided. The process can be executed by a routing and wavelength allocation device, and after receiving a connection request, the device performs routing and wavelength allocation by using the method provided by the embodiment of the invention, and sends an allocation result to optical cross nodes on a path allocated for the connection request, so that the optical cross nodes perform routing and wavelength-related configuration, thereby communicating on the path by using the wavelength allocated for the connection request.

The routing and wavelength allocation device may be a control node, such as a network controller, deployed in the optical network. The device can be deployed at the entrance of the optical network, and can receive a connection request from an access node, and perform routing and wavelength allocation for the connection request.

The following describes the routing and wavelength allocation procedure provided in the embodiment of the present invention in detail with reference to fig. 3. As shown in fig. 3, the process may include the following steps 301 to 305:

step 301: and receiving a connection request, wherein the connection request comprises information of a transmitting end node and a receiving end node.

A connection request refers to a connection request from one access node to another access node of the optical network. Taking fig. 1 as an example, an access node a as a sender node may initiate a connection request to an access node B, which is a receiver node.

The connection request may include information of the sender node and information of the receiver node, and the routing and wavelength allocation apparatus may determine the sender node and the receiver node of the connection request according to the connection request. The information of the sending end node may include address information (such as an IP address) and/or identification information (such as a node identification) of the sending end node, and the information of the receiving end node may include address information (such as an IP address) and/or identification information (such as a node identification) of the receiving end node.

Step 302: and acquiring N wavelength groups, and acquiring candidate path sets corresponding to the N wavelength groups according to the sending end node and the receiving end node, wherein N is an integer greater than or equal to 1.

One wavelength set may include one wavelength or a plurality of wavelengths.

Considering that the optical cross node may or may not be configured with a wavelength converter, or the optical fiber link may or may not be provided with a wavelength converter, or the routing and wavelength allocation apparatus may be configured with a wavelength allocation policy in advance, for example, wavelength conversion is allowed or not allowed for a specific link, and thus wavelength conversion may or may not be enabled on one candidate path. For the different cases, the 1 wavelength set determined by the routing and wavelength allocation device includes one of the following cases:

case 1: if the wavelength group contains one wavelength, the number of links that have used that wavelength is less than the total number of links in the optical network. That is, the wavelengths included in the wavelength set are usable wavelengths.

For example, an optical network includes M links (M is the total number of links, and M is an integer greater than 1), and the wavelengths configured for the optical network are from 1 to k (k is an integer greater than 1). After the routing and wavelength allocation device receives the connection request, if the device determines that the wavelength 1 is allocated to the link of M (M is smaller than M, and M can take a value of 0) for use with respect to the wavelength 1, the device considers that the wavelength 1 is an available wavelength, and can obtain a corresponding candidate path set with respect to the wavelength 1; if the apparatus determines that wavelength 2 has been allocated for use by the M links for wavelength 2, it may discard acquiring the corresponding candidate path set for wavelength 2 if it is deemed that wavelength 2 cannot be allocated any more.

In case 1, the candidate path corresponding to the wavelength group satisfies the wavelength continuity requirement, that is, the same wavelength is always used for communication on the path.

Case 2: if the wavelength group includes a plurality of wavelengths, the number of links that have used the plurality of wavelengths is less than the total number of links in the optical network. That is, a plurality of wavelengths included in the wavelength set are available wavelength combinations.

For example, an optical network includes M links (M is the total number of links, and M is an integer greater than 1), and the wavelengths configured for the optical network are from 1 to k (k is an integer greater than 1). After the routing and wavelength allocation apparatus receives the connection request, if the apparatus determines that the wavelength set 1 has been allocated to an M (M is smaller than M, and M can take a value of 0) link for use with respect to the wavelength set 1{ wavelength 1, wavelength 2}, it considers that the wavelength 1 and the wavelength 2 included in the wavelength set 1 are an available wavelength combination, and can obtain a corresponding candidate path set with respect to the wavelength set 1; if the apparatus determines that wavelength set 2 has been allocated for use by M links for wavelength set 2{ wavelength 3, wavelength 4}, then it is assumed that wavelength set 2 can no longer be allocated, and the acquisition of the corresponding candidate path set for wavelength set 2 may be aborted.

In case 2, one of the plurality of wavelengths is allowed to be converted to another of the plurality of wavelengths at the optical cross node where the wavelength converter is disposed in the candidate path corresponding to the wavelength group and/or at the wavelength converter disposed in the optical fiber link of the candidate path. For example, for a wavelength set { wavelength 1, wavelength 2}, an optical signal may be transmitted on a candidate path corresponding to the wavelength set using wavelength 1, the optical signal may be transmitted on one optical cross node on the path where a wavelength converter is disposed after being converted from wavelength 1 to wavelength 2, and the optical signal may be transmitted on another optical cross node on the path where a wavelength converter is disposed after being converted back to wavelength 1.

Accordingly, the N wavelength sets in step 302 may include one of the following cases:

-only one wavelength is contained in each wavelength group;

-each wavelength group comprises a plurality of wavelengths (such as 2 or more than 2 wavelengths);

a part of the wavelength set contains only one wavelength and another part of the wavelength set contains a plurality of wavelengths.

The candidate path set corresponding to the wavelength group may be regarded as a wavelength layer topology corresponding to the wavelength group, where the wavelength layer topology indicates a network connection condition of a certain wavelength group. Taking an example that one wavelength group includes one wavelength, a corresponding optical network topology may be obtained for the wavelength group, and the optical network topology may include only one or more candidate paths that can use the wavelength for communication between a sending end node and a receiving end node of a connection request.

Taking the optical network shown in fig. 1 as an example, assuming that the optical cross nodes in the optical network are not configured with wavelength converters and the optical fiber links are not provided with wavelength converters, that is, a connection request needs to use one same wavelength all the time, fig. 4 shows a wavelength layer topology corresponding to wavelength 1, and fig. 5 shows a wavelength layer topology corresponding to wavelength 2. In fig. 4, the optical cross-over node 4 has three degrees of freedom, i.e. 3 paths (4- >2,4- >5,4- >11) can be selected for the wavelength 1 at the optical cross-over node 4. In fig. 5, the optical cross-over node 4 has two degrees of freedom, i.e. 2 paths (4- >2,4- >5) can be selected for the wavelength 2 at the optical cross-over node 4.

In some preferred embodiments, the implementation of step 302 may include: after receiving the connection request, the routing and wavelength allocation device acquires information of all available wavelengths and available wavelength combinations in the optical network; then, the routing and allocating device obtains each available wavelength and the candidate path set corresponding to the available wavelength combination according to the information of the sending end node and the receiving end node contained in the connection request, wherein the starting point of each candidate path is the sending end node, and the ending point of each candidate path is the receiving end node. The device can obtain the information of available wavelength or available wavelength combination according to the routing and wavelength allocation information of the optical network, and can obtain the candidate path between the two nodes according to the sending end node and the receiving end node of the connection request.

For example, the available wavelengths and available wavelength combinations, and their corresponding candidate path sets, may be as follows:

wavelength set 1{ wavelength 1}, corresponding set of candidate paths { path 1, path 2 };

wavelength set 2{ wavelength 1, wavelength 2}, corresponding candidate path set { path 1, path 3, path 4}

The above preferred embodiment is described by taking an example of obtaining information of all available wavelengths and available wavelength combinations in an optical network, and obtaining candidate path sets corresponding to each available wavelength and each available wavelength combination, and of course, in some other embodiments, combination information of part of available wavelengths and available wavelengths in the optical network may be obtained, and a corresponding candidate path set may be obtained for the obtained available wavelengths and/or available wavelength combinations; or, for the obtained combination of the available wavelength and the available wavelength, when obtaining the corresponding candidate path set, selecting a part of available wavelengths and/or available wavelength combinations from the obtained combination of the available wavelength and the available wavelength, and obtaining the corresponding candidate path set for the selected available wavelength and/or available wavelength combinations.

Step 303: and acquiring weight calculation parameters of candidate paths in the candidate path set, wherein at least one parameter in the weight calculation parameters of one candidate path is calculated according to the characteristic parameters of the optical cross node on the candidate path.

Wherein the characteristic parameter of an optical cross-point node may reflect the physical and/or optical characteristics of the optical cross-point node. For example, the characteristic parameters of an optical cross-node may include one or a combination of the following parameters: the instantaneous blocking probability, crosstalk parameter, power loss parameter, polarization dependent loss parameter, are described separately below.

(1) Instantaneous block probability

The parameter is used for representing the probability corresponding to the number of the existing wavelengths in the optical cross node; wherein, the probability corresponding to the number of the existing wavelengths represents: the probability that the next connection request is blocked by the optical cross-node at this number of existing wavelengths. Wherein the existing wavelength of an optical cross node is the wavelength used by the optical cross node.

For some optical cross nodes, in the presence of a certain number of wavelengths in the optical cross node, the new optical signal may not be switched, which is called instantaneous blocking of the optical cross node. The instantaneous blocking rate of an optical cross-point node is related to the number of wavelengths present at the node, and in general, the greater the number of wavelengths present for an optical cross-point node, the greater the probability that the next connection request will be blocked.

(2) Crosstalk parameter

The parameter is used for representing the interference size corresponding to the number of the existing wavelengths in the optical cross node; wherein, the interference size corresponding to the number of the existing wavelengths represents: the optical cross-node is in this number of existing wavelengths, the wavelength to which the next connection request is assigned is subject to interference values from the corresponding number of existing wavelengths in the optical cross-node.

When the optical cross matrix of the optical cross node performs port crossing, signals from other ports may cause crosstalk to a destination port, as shown in fig. 6, and a part of optical signals from the left port 1 to the right port 1 may leak to the port 2 (as shown by a dotted line in the figure). The crosstalk may be from the same wavelength or from different wavelengths, and is generally more severe at the same wavelength. The magnitude of signal crosstalk is related to the number of wavelengths and path selection present in the optical cross-node.

FIG. 7 shows the OSNR (Optical Signal Noise Ratio) cost of the 100Gb/s PM-QPSK (polarized-multiplexed Quadrature Phase Shift Keying) system due to Signal crosstalk during Optical interleaving: in the case of-16 dB crosstalk, the system has an OSNR penalty of 1 dB. From the results of FIG. 7, the effect of the physical properties of the optical cross-over node on the performance of a 100Gb/s coherent system is significant.

(3) Power loss parameter

This parameter is used to represent the insertion loss value of the optical cross-node. Where insertion loss refers to the loss of load power occurring somewhere in the transmission system due to the insertion of an element or device, it is expressed as the ratio in decibels of the power received on the load before the element or device is inserted to the power received on the same load after insertion. The power loss, which is expressed in terms of a power loss parameter, is lost for each optical exchange of an optical signal.

(4) Polarization dependent loss parameter

At present, optical signals of a polarization multiplexing high-order debugging format are widely used for transmission, and the optical signals are sensitive to polarization-dependent loss. As shown in fig. 8, the wavelength division signal is first decomposed into different wavelength signals by a demultiplexer, then each wavelength is separated into orthogonal polarizations by a polarization beam splitter, two orthogonal polarizations are switched to a destination port by two optical cross matrixes, and then the wavelength division signal is transmitted to the next optical cross node by polarization beam combination and wavelength multiplexing.

Polarization splitting is typically not accurate for 50% -50% splitting, resulting in inconsistent signal loss in both polarization states. As shown in fig. 9, the optical signal is divided into two optical signals of horizontal polarization and vertical polarization after being subjected to polarization beam splitting, theoretically, the power ratio of the two optical signals is 1:1, and the two optical signals are subjected to polarization beam combining after passing through the optical switch 1 and the optical switch 2. However, the actual device cannot do so accurately, and there is a difference in power between the horizontal Polarization and the vertical Polarization, which is called Polarization Dependent Loss (PDL). PDL destroys the orthogonality of the polarization multiplexed Signal, and has a certain effect on a Digital Signal Processor (DSP).

FIG. 10 shows the OSNR cost of a 100Gb/s PM-QPSK system brought by the PDL phenomenon in the optical interleaving process: a PDL of about 0.5dB can bring a system cost of 1 dB. From the results of fig. 10, the effect of the physical properties of the optical cross-over node on the performance of the coherent system at 100Gb/s is significant.

The above listed types of characteristic parameters of the optical cross node are only examples, and the embodiments of the present invention do not exclude that other characteristic parameters of the optical cross node are also included, which may affect signal transmission.

In the above-listed characteristics and parameters of the optical cross node, the power loss and the polarization-dependent loss are physical properties of the optical cross node and do not change depending on the wavelength, so the power loss parameter and the polarization-dependent loss parameter can be calibrated in advance, that is, values of the two parameters are configured in advance. The instantaneous blocking probability and crosstalk are related to the state of the optical cross node (for example, the number of existing wavelengths and the information of the internal configuration of the node), so that the state and/or configuration information of the optical cross node may be first obtained, and the power loss parameter and/or the polarization-dependent loss parameter may be determined according to the obtained state and/or configuration information of the optical cross node.

For example, the process of obtaining the instantaneous blocking probability of the optical cross node may include: firstly, acquiring configuration information of an optical cross node, wherein the configuration information at least comprises the number of existing wavelengths in the optical cross node; then, according to the number of the existing wavelengths in the optical cross node, inquiring the corresponding relation between the number of the wavelengths and the instant blocking probability to obtain the instant blocking probability corresponding to the number of the existing wavelengths in the optical cross node. The corresponding relation between the wavelength number and the instant blocking probability can be configured in advance. The corresponding relation can be obtained through simulation test or statistical analysis of transmission performance data.

As another example, the obtaining of the crosstalk parameter of the optical cross node may include: firstly, acquiring configuration information of an optical cross node, wherein the configuration information at least comprises the number of existing wavelengths in the optical cross node; then, according to the number of the existing wavelengths in the optical cross node, the corresponding relation between the number of the wavelengths and the crosstalk parameters is inquired, and the crosstalk parameters corresponding to the number of the existing wavelengths in the optical cross node are obtained. The corresponding relation between the wavelength number and the instant blocking probability can be configured in advance. The corresponding relation can be obtained through simulation test or statistical analysis of transmission performance data.

The characteristic parameters of the optical cross nodes listed above reflect the physical and/or optical characteristics of the optical cross nodes, and in implementation, some characteristic parameters of some or all optical cross nodes on a candidate path may be accumulated or may be accumulated and then averaged to obtain a weight calculation parameter of the candidate path. For example, the instantaneous blocking probabilities of all optical cross nodes on a candidate path may be summed up, and the result of the cumulative summation may be used as the instantaneous blocking probability of the candidate path to participate in the routing computation.

In order to take account of the characteristics of the optical cross node and the characteristics of the optical fiber link, so as to make the routing and wavelength allocation more reasonable, in the embodiment of the present invention, preferably, in the process of calculating the routing and wavelength allocation, in addition to the characteristic parameters of the optical cross node, the characteristic parameters of the link may be further introduced. That is, the weight calculation parameter may further include a link characteristic parameter.

Preferably, the link characteristic parameters of a path may include one or a combination of the following parameters:

-a wavelength utilization factor representing the ratio of the number of wavelengths already used on a path to the number of all available wavelengths on the path;

-a power loss parameter representing an insertion loss value of a path;

-a link cost parameter for indicating a service cost size of a path. Preferably, the parameter may be a normalized cost parameter. For example, a service cost per unit length of a certain fiber may be defined to be 1, and other types of fiber may represent C times 1 (C is greater than zero) with respect to its service cost. The specific selection of which type of optical fiber and how long the distance is as a unit length can be customized.

-a link delay parameter indicating the size of the delay of a path. The parameter may be a normalized delay parameter. For example, it may be defined that the time delay per unit length of a certain fiber is 1, then other types of fiber may represent D times 1 (D is greater than zero) with respect to its time delay. The specific selection of which type of optical fiber and how long the distance is as a unit length can be customized.

Among the above-mentioned link characteristic parameters, a power loss parameter, a link cost parameter, and a link delay parameter may be configured in advance. These parameters can be obtained by means of simulation tests and the like.

Step 304: and calculating the weight value of the candidate path according to the weight calculation parameter of the candidate path.

In this step, the weight value of the candidate path may be calculated according to the following formula:

wherein cost represents the weight value of a candidate path, N represents the number of weight calculation parameters corresponding to the candidate path, N is an integer greater than or equal to 1, and P_iα, the ith weight calculation parameter of the N weight calculation parameters corresponding to the candidate path_iRepresents P_iCorresponding weight value α_iCan be a value greater than zero and less than 1,

of course α_iOther values are also possible.

Wherein at least one of the N weight calculation parameters is an accumulated sum of characteristic parameters of the optical cross node on the candidate path or an average value of the accumulated sum.

When the weight value cost of the candidate path is calculated according to the formula (1), if the value of the accumulated sum of the characteristic parameters of the optical cross node is normalized, the value range of the weight value cost of the candidate path can be between 0 and 7.

Generally, the larger the weight value of a candidate path, the worse the transmission performance.

As an example, for a candidate path, the instantaneous blocking probabilities of all optical cross nodes on the candidate path may be accumulated and calculated, the crosstalk parameters may be accumulated and calculated, the polarization dependent loss parameters may be accumulated and calculated, and the power loss parameters may be accumulated and calculated, respectively; the total power loss parameter is then calculated according to the following formula:

wherein, P _ total power loss represents the sum of power loss of a candidate path, P _ path represents the insertion loss of the candidate path, M represents the number of optical cross nodes on the candidate path, and P _ node_jIndicating the insertion loss of the jth optical cross node of the M optical cross nodes on the candidate path. Wherein the insertion loss value of one path and the insertion loss value of one optical cross node can be configured in advance.

Preferably, in the case that the insertion loss of all optical cross nodes in the optical network is the same, a simplified formula of the above formula (2) is as follows:

where β is the link insertion loss coefficient, L is the link length, P _ node represents the insertion loss of an optical cross node, and M represents the number of optical cross nodes on the candidate path.

Then, the cumulative sum of the instantaneous blocking probabilities, the cumulative sum of the crosstalk parameters, the cumulative sum of the polarization dependent loss parameters, and the calculation result P _ totalpower loss of the formula (2) or the formula (3) of all the optical cross nodes on the candidate path are substituted into the formula (1) to calculate, and the weight value of the candidate path is obtained.

Optionally, to further improve flexibility and reasonableness of routing and wavelength allocation, in some embodiments, before calculating the weight value of a candidate path, the weight value corresponding to each weight calculation parameter of the candidate path may be determined according to the service level corresponding to the received connection request.

The service level parameter is usually carried in the header portion of the connection request, although other methods for obtaining the service level are not excluded in the embodiments of the present invention. The weight values of a different set of weight calculation parameters may be set for different service levels. For example, if a certain service level has a high requirement on link cost and link delay, the weighted values corresponding to the link cost parameter and the link delay parameter in a group of weighted values corresponding to the service level have large values; for another example, if the tolerance of a certain service level to the polarization-dependent loss and the crosstalk is small, the weight value corresponding to the polarization-dependent loss parameter and the crosstalk parameter is large in a group of weight values corresponding to the service level.

Step 305: and determining the path and the wavelength used by the connection request according to the weight value of the candidate path and the wavelength group corresponding to the candidate path set.

In this step, in some embodiments, a candidate path with the smallest weight value may be selected according to the weight value of the candidate path; and determining the selected candidate path with the minimum weight value as the path used by the connection request, and determining the wavelength in the wavelength group corresponding to the candidate path set to which the candidate path with the minimum weight value belongs as the wavelength used by the connection request. Further, if there are multiple candidate paths with the smallest weight value, one candidate path is selected from the multiple candidate paths, for example, one path may be randomly selected from the multiple candidate paths or one path may be selected according to a set rule. Through the above process, it can be seen that, since the available wavelengths or wavelength combinations exist on the candidate paths, the wavelength allocation is also completed at the same time after the paths are selected from the candidate paths through the route calculation.

In other embodiments, a candidate path with a weight value smaller than a set threshold value may also be selected according to the weight value of the candidate path; and determining the selected candidate path with the weight value smaller than the set threshold value as the path used by the connection request, and determining the wavelength in the wavelength group corresponding to the candidate path set to which the candidate path with the weight value smaller than the set threshold value belongs as the wavelength used by the connection request. Further, if there are multiple candidate paths with weight values smaller than the set threshold, one candidate path is selected from the multiple candidate paths, for example, one path may be randomly selected from the multiple candidate paths or one path may be selected according to a set rule.

Further, if the weight values of all candidate paths are greater than the threshold, the current routing and wavelength assignment fails, and the received connection request is blocked. The value of the threshold value should be able to ensure that paths with weight values cost smaller than the threshold value can be communicated. The threshold value can be preset and can be obtained according to simulation test or statistical analysis of communication state data.

In some preferred embodiments, in step 302 of the above process, after receiving the connection request, the routing and wavelength allocation apparatus may obtain all currently available wavelengths and available wavelength combinations in the optical network, form N wavelength groups, and obtain a candidate path set corresponding to each wavelength group; in step 303, the routing and wavelength allocation apparatus may obtain weight calculation parameters for all candidate paths in all candidate path sets; in step 304, the routing and wavelength allocation device may calculate the weight value of each candidate path according to the weight calculation parameter of the candidate path; in step 305, the path and the wavelength used by the connection request may be determined according to the weight value of each candidate path and the wavelength group corresponding to the candidate path set to which the candidate path belongs. In this way, the routing and wavelength allocation device can select the optimal path of the whole network to allocate to the received connection request.

As can be seen from the above description, in the above embodiments of the present invention, on one hand, at least one of the weight calculation parameters of a candidate path is calculated according to the characteristic parameters of the optical cross node on the candidate path, that is, the physical and/or optical characteristics of the optical cross node are used as the basis for routing and wavelength allocation, so as to improve the reasonableness of routing and wavelength allocation.

On the other hand, in the foregoing prior art, only the first wavelength is selected from the idle wavelength set satisfying the wavelength continuity for availability evaluation, and if the evaluation is not possible, the connection request is blocked, so that the probability that the connection request is blocked is high. In the embodiment of the invention, the route calculation and the wavelength allocation are combined together, and after the path is selected, because the path has the available wavelength, the situation that the connection request is blocked when the wavelength evaluation is carried out again and the evaluation fails is avoided, thereby reducing the probability that the connection request is blocked compared with the prior art.

On the other hand, the wavelength service condition of a certain optical cross node in the optical network can be conveniently calculated based on the wavelength layer topology, and the wavelength crosstalk can be quickly calculated. For example, the optical cross-over node 4 in fig. 4 has three degrees of freedom, while the wavelength layer topology shows that wavelength 1 can be available in all three directions, i.e. there is no crosstalk of wavelength 1 at the optical cross-over node 4; as another example, in fig. 5, wavelength 2 of optical cross-over node 4 is available in only two directions, indicating that there is crosstalk of one wavelength 2 at optical cross-over node 4.

In order to more clearly understand the above embodiments of the present invention, the following provides a routing and wavelength allocation process in a practical application scenario with reference to fig. 11.

As shown in fig. 11, the process may include the following steps:

step 1: a connection request is received.

Step 2: a wavelength layer topology of the optical network is generated. That is, the available wavelength and/or the combination of the available wavelengths are/is obtained to obtain N wavelength groups, and the candidate path sets corresponding to the N wavelength groups are obtained according to the information of the transmitting end node and the receiving end node included in the connection request.

And 3, selecting an objective function according to the service level of the signal requested to be transmitted by the connection request, wherein one service level corresponds to one objective function, and the objective functions corresponding to different service levels can be the same or different.

And 4, step 4: existing wavelengths and configuration information of optical cross-nodes on the candidate paths are obtained.

And 5: and (4) calculating the crosstalk and instant blocking probability of the optical cross nodes on the candidate paths according to the information acquired in the step (4).

Step 6: and calculating the weight value of the candidate path. Specifically, the calculation can be performed by the aforementioned formula (1).

And 7: if the weight value of at least one candidate path is smaller than the threshold value, the step 8 is switched to, otherwise, the route distribution for the received connection request is not indicated, and the step 11 is switched to.

And 8: and selecting the candidate path with the minimum weight value according to the weight value of the candidate path, and obtaining the wavelength allocated to the connection request according to the wavelength group corresponding to the candidate path set to which the path with the minimum weight value belongs.

And step 9: and updating the optical network routing table. The routing table stores the path and wavelength topology information of the current optical network, so as to perform subsequent routing and wavelength allocation.

Step 10: and sending the routing and wavelength allocation results to the optical cross nodes on the path with the minimum weight value so as to enable the optical cross nodes to carry out transmission configuration.

Step 11: and (3) whether a new connection request is received, if so, turning to the step 2, and otherwise, ending the process.

Based on the same technical concept, the embodiment of the invention also provides a routing and wavelength allocation device. The device can realize the routing and wavelength allocation process provided by the embodiment. The apparatus may be a control device, such as a network controller, in an optical network.

Referring to fig. 12, a schematic structural diagram of a routing and wavelength allocation apparatus according to an embodiment of the present invention is shown, where the apparatus may include: an interface 1201, a processing unit 1202 and a memory 1203. A processing unit 1202 for controlling the operation of the apparatus; the memory 1203 may include both read-only memory and random access memory for providing instructions and data to the processing unit 1202. A portion of the memory 1203 may also include non-volatile row random access memory (NVRAM). The various components of the device are coupled together by a bus system, where bus system 1209 includes a power bus, a control bus, and a status signal bus in addition to a data bus. For clarity of illustration, however, the various buses are designated as the bus system 1209 in the figure.

The routing and wavelength allocation procedure disclosed in the embodiments of the present invention may be applied to the processing unit 1202, or implemented by the processing unit 1202. In the implementation process, the steps of the routing and wavelength allocation flow implemented by the apparatus may be implemented by an integrated logic circuit of hardware in the processing unit 1202 or by instructions in the form of software. The processing unit 1202 may be a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or the like that implement or perform the methods, steps, and logic blocks disclosed in embodiments of the present invention. A general purpose processor may be a microprocessor or any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present invention may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in the processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in the memory 1203, and the processing unit 1202 reads information in the memory 1203, and completes the steps of the routing and wavelength allocation procedure in combination with hardware thereof.

In particular, the processing unit 1202 may be configured to perform the routing and wavelength allocation procedures described in the foregoing embodiments. The specific implementation process of the flow can be referred to the aforementioned flow shown in fig. 3, and is not repeated here.

Based on the same technical concept, the embodiment of the invention also provides a routing and wavelength allocation device. The device can realize the routing and wavelength allocation process provided by the embodiment.

Referring to fig. 13, a schematic structural diagram of a routing and wavelength allocation apparatus according to an embodiment of the present invention is shown, where the apparatus may include: a receiving unit 1301, a first obtaining unit 1302, a second obtaining unit 1303, a calculating unit 1304, and a determining unit 1305, wherein:

a receiving unit 1301, configured to receive a connection request, where the connection request includes information of a sender node and a receiver node;

a first obtaining unit 1302, configured to obtain N wavelength groups, and obtain candidate path sets corresponding to the N wavelength groups according to the sender node and the receiver node, where N is an integer greater than or equal to 1, and one wavelength group includes 1 or multiple wavelengths;

a second obtaining unit 1303, configured to obtain weight calculation parameters of candidate paths in the candidate path set, where at least one of the weight calculation parameters of a candidate path is calculated according to a characteristic parameter of an optical cross node on the candidate path;

a calculating unit 1304, configured to calculate a parameter according to a weight of the candidate path, and calculate a weight value of the candidate path;

the determining unit 1305 is configured to determine a path and a wavelength used by the connection request according to the weight value of the candidate path and the wavelength group corresponding to the candidate path set to which the candidate path belongs.

Preferably, if a wavelength is included in a wavelength group, the number of links that have used the wavelength is less than the total number of links; alternatively, if a plurality of wavelengths are included in one wavelength set, the number of links that have used the plurality of wavelengths is less than the total number of links.

Preferably, if a wavelength group includes a wavelength, the candidate path corresponding to the wavelength group satisfies the requirement of wavelength continuity; if a wavelength group includes a plurality of wavelengths, one of the plurality of wavelengths is allowed to be converted to another of the plurality of wavelengths at an optical cross node where a wavelength converter is disposed in a candidate path corresponding to the wavelength group and/or at a wavelength converter disposed in an optical fiber link of the candidate path.

Preferably, the characteristic parameters of the optical cross-node comprise one or a combination of the following parameters: instantaneous blocking probability, crosstalk parameters, power loss parameters, polarization dependent loss parameters. The meaning of these parameters is as described above and will not be repeated here.

Accordingly, the second obtaining unit 1303 may perform the following steps in the obtaining process of obtaining the instantaneous blocking probability of the optical cross node: acquiring configuration information of an optical cross node, wherein the configuration information at least comprises the number of existing wavelengths in the optical cross node; and inquiring the corresponding relation between the number of the wavelengths and the instant blocking probability according to the number of the existing wavelengths in the optical cross node to obtain the instant blocking probability corresponding to the number of the existing wavelengths in the optical cross node.

Accordingly, the second obtaining unit 1303 may perform the following steps in the process of obtaining the crosstalk parameter of the optical cross node: acquiring configuration information of an optical cross node, wherein the configuration information at least comprises the number of existing wavelengths in the optical cross node; and inquiring the corresponding relation between the number of the wavelengths and the crosstalk parameters according to the number of the existing wavelengths in the optical cross node to obtain the crosstalk parameters corresponding to the number of the existing wavelengths in the optical cross node.

Preferably, the weight calculation parameters further include: a link characteristic parameter; the link characteristic parameters of a path include one or a combination of the following parameters: wavelength utilization, power loss parameters, link cost parameters, and link delay parameters. Rate loss parameter, polarization dependent loss parameter.

Preferably, the calculating unit 1304 may calculate the weight value of the candidate path according to formula (1). The formula (1) and the description of the relevant parameters can be referred to the foregoing embodiments, and are not repeated here.

Preferably, the calculation unit 1304 is further operable to: before calculating the weight value of a candidate path, determining the weight value corresponding to the weight calculation parameter of the candidate path according to the service level corresponding to the connection request.

Preferably, the determining unit 1305 may select a candidate path with the smallest weight value according to the weight value of the candidate path, determine the selected candidate path with the smallest weight value as the path used by the connection request, and determine the wavelength in the wavelength group corresponding to the candidate path set to which the candidate path with the smallest weight value belongs as the wavelength used by the connection request.

In the apparatus shown in fig. 13, the receiving unit 1301 may be implemented by an interface module (e.g., as interface 1201 in fig. 12); the functions of the first acquiring unit 1302, the second acquiring unit 1303, the calculating unit 1304, and the determining unit 1305 may be implemented by a processing unit (e.g., the processing unit 1202 as shown in fig. 12). Or, the units are different software modules in the processing unit, software codes of the software modules are pre-configured in the memory, and the processing unit reads and executes the software codes in the memory to implement corresponding functions or execute corresponding operations, thereby completing the routing and wavelength allocation process described in the above embodiments.

In summary, the embodiments of the present invention comprehensively consider the physical and/or optical characteristics of the optical cross node, such as the influence of crosstalk and polarization dependent loss phenomena of the optical cross node on the signal, so that the routing calculation is more accurate. In addition, the embodiment of the invention also comprehensively considers the problems of route calculation and wavelength allocation, carries out route calculation in the path corresponding to the available wavelength, and simplifies the algorithm implementation process compared with the prior art.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, implement the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A method for routing and wavelength allocation, comprising:

determining a path and a wavelength used by the connection request according to the weight value of the candidate path and the wavelength group corresponding to the candidate path set;

wherein the characteristic parameters of the optical cross node include one or a combination of the following parameters:

an instantaneous blocking probability for representing the probability corresponding to the number of wavelengths existing in the optical cross node;

a crosstalk parameter for indicating a magnitude of interference corresponding to a number of wavelengths existing in the optical cross node;

a polarization dependent loss parameter.

2. The method of claim 1, wherein if a wavelength is included in a wavelength group, the number of links that have used that wavelength is less than the total number of links; or

If a wavelength group contains multiple wavelengths, the number of links that have used the multiple wavelengths is less than the total number of links.

3. The method according to claim 1 or 2, wherein if a wavelength group comprises a wavelength, the candidate path corresponding to the wavelength group satisfies the wavelength continuity requirement;

if a wavelength group includes a plurality of wavelengths, one of the plurality of wavelengths is allowed to be converted to another of the plurality of wavelengths at an optical cross node where a wavelength converter is disposed in a candidate path corresponding to the wavelength group and/or at a wavelength converter disposed in an optical fiber link of the candidate path.

4. The method of claim 1, wherein the obtaining of the instantaneous blocking probability of the optical cross-node comprises:

acquiring configuration information of an optical cross node, wherein the configuration information at least comprises the number of existing wavelengths in the optical cross node;

and inquiring the corresponding relation between the number of the wavelengths and the instant blocking probability according to the number of the existing wavelengths in the optical cross node to obtain the instant blocking probability corresponding to the number of the existing wavelengths in the optical cross node.

5. The method of claim 1, wherein the obtaining of the crosstalk parameters of the optical cross-node comprises:

and inquiring the corresponding relation between the number of the wavelengths and the crosstalk parameters according to the number of the existing wavelengths in the optical cross node to obtain the crosstalk parameters corresponding to the number of the existing wavelengths in the optical cross node.

6. The method of claim 1, 2,4 or 5, wherein the weight calculation parameters further comprise: a link characteristic parameter;

a power loss parameter representing an insertion loss value of a path;

a link cost parameter for indicating a service cost size of a path;

and the link delay parameter is used for indicating the delay size of one path.

7. The method of claim 1, 2,4 or 5, wherein the calculating the weight value of the candidate path according to the weight calculation parameter of the candidate path comprises:

8. The method of claim 7, wherein prior to calculating the weight value for a candidate path, further comprising:

and determining a weight value corresponding to the weight calculation parameter of the candidate path according to the service level corresponding to the connection request.

9. The method according to claim 1, 2,4 or 5, wherein the determining the path and the wavelength used by the connection request according to the weight value of the candidate path and the wavelength group corresponding to the candidate path set includes:

10. A routing and wavelength allocation apparatus, comprising:

a determining unit, configured to determine a path and a wavelength used by the connection request according to a weight value of the candidate path and a wavelength group corresponding to the candidate path set to which the candidate path belongs;

the characteristic parameters of the optical cross-node include one or a combination of the following parameters:

a polarization dependent loss parameter.

11. The apparatus of claim 10, wherein if a wavelength group comprises a wavelength, the number of links that have used that wavelength is less than the total number of links; or

12. The apparatus according to claim 10 or 11, wherein if a wavelength group comprises a wavelength, the candidate path corresponding to the wavelength group satisfies the wavelength continuity requirement;

13. The apparatus of claim 10, wherein the second obtaining unit is specifically configured to: in the process of obtaining the instant blocking probability of the optical cross node, the following steps are executed:

14. The apparatus of claim 10, wherein the second obtaining unit is specifically configured to: in the process of obtaining crosstalk parameters of the optical cross node, the following steps are executed:

15. The apparatus as claimed in claim 10, 11, 13 or 14, wherein the weight calculation parameters further include: a link characteristic parameter;

a power loss parameter representing an insertion loss value of a path;

a link cost parameter for indicating a service cost size of a path;

and the link delay parameter is used for indicating the delay size of one path.

16. The apparatus according to claim 10, 11, 13 or 14, wherein the computing unit is specifically configured to:

wherein cost represents the weight value of a candidate path, N represents the number of weight calculation parameters corresponding to the candidate path, N is an integer greater than or equal to 1, and P_iIn N weight calculation parameters representing the candidate pathα_iRepresents P_iA corresponding weight value; wherein at least one of the N weight calculation parameters is an accumulated sum of characteristic parameters of the optical cross node on the candidate path or an average value of the accumulated sum.

17. The apparatus of claim 16, wherein the computing unit is further to:

before calculating the weight value of a candidate path, determining the weight value corresponding to the weight calculation parameter of the candidate path according to the service level corresponding to the connection request.

18. The apparatus according to claim 10, 11, 13 or 14, wherein the determining unit is specifically configured to: