CN114697262A

CN114697262A - Path calculation method, path calculation server and communication system

Info

Publication number: CN114697262A
Application number: CN202011606217.9A
Authority: CN
Inventors: 刘盼; 叶友道; 王振宇
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2020-12-28
Filing date: 2020-12-28
Publication date: 2022-07-01
Also published as: WO2022143023A1

Abstract

The invention provides a path calculation method, a path calculation server and a communication system, wherein the method comprises the following steps: a path computation server (PCE) receives a path computation request message sent by a path computation request client (PCC); the PCE carries out path computation according to the path computation request message and service transmission parameters set by the SDO; and the PCE sends the path calculation result to the PCC. In the embodiment of the invention, the SDO technology of the software defined optical module is fused with the PCEP, so that the self-adaptive service transmission performance of the optical layer can be effectively improved, the optimal matching scheme of capacity and distance is realized, and the network viability is improved.

Description

Path calculation method, path calculation server and communication system

Technical Field

The embodiment of the invention relates to the field of communication, in particular to a path calculation method, a path calculation server and a communication system.

Background

In the prior art, an intelligent direction focusing Optical Transport Network (OTN) product solution realizes Network intelligent evolution from a traditional Network to an autonomous Network by adding an intelligent and open new generation management and control product on the basis of the traditional Network. This part is realized by adding related functions to the OTN device and the management and control platform respectively based on the existing OTN device and the management and control plane.

A Path Computation Element Communication Protocol (PCEP) is a Communication Protocol, and is an application layer Protocol based on Transmission Control Protocol (TCP), and in an OTN SDN (Software Defined Network) solution, the PCEP Protocol is a southbound interface Protocol. The PCEP protocol defines a Path Computation Element (PCE) and a Path Computation Client (PCC) or a communication standard between PCEs, and mainly transfers Path information of a Layered Service Provider (LSP) through the PCEP protocol, and after a Path is computed by an SDN controller, the PCEP protocol converts the Path information into an SR label stack and sends the SR label stack to an OTN device control plane. The PCEP protocol is a communication protocol for interaction between OTN devices and the management and control plane.

Because of the limitation of the prior art, PCE in the PCEP protocol standard is a functional entity specially responsible for path computation, and the current service function is single, and the objective of optical layer intellectualization in the true sense cannot be realized. Aiming at the problems that capacity, distance and frequency spectrum of optical layer transmission seriously affect optical transmission performance, for example, the distance is too long, the optical transmission performance is degraded, or the transmission capacity is damaged due to the degradation of current signals, or the service quality is poor due to non-optimal transmission frequency spectrum, and the like, the traditional solution is to adjust the optical transmission performance by replacing a hardware optical module, adding a relay station, deleting a service adjustment transmission channel, and the like, which inevitably has higher labor and technical cost.

Disclosure of Invention

The embodiment of the invention provides a path calculation method, a path calculation server and a communication system, which at least solve the problem of higher labor and technical cost caused by the fact that the optical transmission performance needs to be adjusted by replacing a hardware optical module, adding a relay station, deleting a service adjusting transmission channel and the like in the related art.

According to an embodiment of the present invention, there is provided a path calculation method including: a path computation server (PCE) receives a path computation request message sent by a path computation request client (PCC); the PCE carries out path calculation according to the path calculation request message and service transmission parameters set by the SDO; and the PCE sends the path calculation result to the PCC.

In an exemplary embodiment, before the PCE receives the path computation request message sent by the PCC, the PCE further includes: the PCE establishes a communication link with the PCC based on a path computation element communication protocol PCEP.

In an exemplary embodiment, before the PCE performs the path computation according to the path computation request message and the service transmission parameter set by the software defined optical module SDO, the PCE further includes: and setting the service transmission parameters in the SDO according to service transmission scenes.

In one exemplary embodiment, the traffic transmission parameters include at least one of: signal type, modulation code type, FEC coding error correction type, grid width, DSP parameters.

In an exemplary embodiment, the PCE performs path computation according to the path computation request message and the service transmission parameters set by the SDO, including: and the PCE analyzes the path computation request message, and utilizes routing information stored in a Traffic Engineering Database (TED) to match the service transmission parameters based on the transmission performance of the path so as to generate an optical layer modulation command set.

In an exemplary embodiment, the PCE sending the path computation result to the PCC includes: the PCE sends the set of optical layer modulation commands to the PCC.

In one exemplary embodiment, the optical layer modulation command set includes at least one of: code modulation shaping, spectrum shaping and dynamic damage shaping.

In an exemplary embodiment, after the PCE sends the set of optical layer modulation commands to the PCC, the PCE further includes: and the PCE receives the result of the PCC feedback for modulating or adjusting the optical module based on the optical layer modulation command set.

According to another embodiment of the present invention, there is provided a computation path server PCE, including: the communication module is used for receiving a path calculation request message sent by a path calculation request client PCC and sending a path calculation result to the PCC; the software defined optical module SDO is used for setting service transmission parameters; and the path calculation module is used for calculating the path according to the path calculation request message and the service transmission parameters set by the SDO.

In an exemplary embodiment, the communication module is further configured to establish a communication link with the PCC based on a path computation element communication protocol PCEP.

In one exemplary embodiment, the PCE further includes: a traffic engineering database TED for storing routing information; the path computation module is further configured to parse the path computation request message, and match the service transmission parameters based on the transmission performance of the path by using the routing information stored in the TED to generate an optical layer modulation command set.

In an exemplary embodiment, the communication module is further configured to receive a result of the PCC feedback adjusting a light module based on the set of optical layer modulation commands.

According to yet another embodiment of the present invention, there is also provided a communication system based on a path computation element communication protocol, PCEP, the communication system including: a computation path server PCE in one or more of the above embodiments, and one or more computation path request clients PCC, wherein the PCE and the PCC interact based on PCEP protocol.

In one exemplary embodiment, the path computation model of the PCE includes: a centralized computation model of one PCE control or a distributed computation model of multiple PCE controls.

According to a further embodiment of the present invention, there is also provided a computer-readable storage medium having a computer program stored thereon, wherein the computer program is arranged to perform the steps of any of the above method embodiments when executed.

According to yet another embodiment of the present invention, there is also provided an electronic device, including a memory in which a computer program is stored and a processor configured to execute the computer program to perform the steps in any of the above method embodiments.

In the embodiment of the invention, the SDO technology of the software defined optical module is fused with the PCEP, so that the self-adaptive service transmission performance of the optical layer can be effectively improved, the optimal matching scheme of capacity and distance is realized, and the network viability is improved.

Drawings

FIG. 1 is a flow chart of a path computation method according to an embodiment of the invention;

FIG. 2 is a block diagram of a computational-path server according to an embodiment of the present invention;

FIG. 3 is a block diagram of a computational routing server according to an alternative embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a communication system based on a PCE centralized computation model according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a basic communication model of PCC/PCE in a PCEP-based protocol according to an embodiment of the present invention;

FIG. 6 is a block diagram of a PCEP protocol + SDO implementation of an embodiment of the present invention;

fig. 7 is a schematic diagram of the content of relevant parameters of a service board card based on the SDO technology according to an embodiment of the present invention;

fig. 8 is a schematic diagram of an SDO optimization application scenario in a long-distance transmission scenario according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of an optimized application scenario in an OADM/ROADM cascaded networking scenario according to an embodiment of the present invention;

fig. 10 is a schematic diagram of an application scenario of the SDO spectrum shaping dispersion pre-compensation according to an embodiment of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings in conjunction with the embodiments.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.

Example 1

In this embodiment, a path calculation method is provided, and fig. 1 is a flowchart of a method according to an embodiment of the present invention, as shown in fig. 1, the method includes the following steps:

step S102, a path computation server (PCE) receives a path computation request message sent by a path computation request client (PCC);

step S104, the PCE carries out path computation according to the path computation request message and the service transmission parameters set by the SDO;

step S106, the PCE sends the path computation result to the PCC.

Before step S102 in this embodiment, the PCE establishes a communication link with the PCC based on a path computation element communication protocol PCEP.

Before step S104 in this embodiment, the method may further include: and setting the service transmission parameters in the SDO according to service transmission scenes.

In this embodiment, the service transmission parameter includes at least one of the following: signal type, modulation code type, FEC coding error correction type, grid width, DSP parameters.

In step S104 of this embodiment, the PCE parses the path computation request message, and matches the service transmission parameters based on the transmission performance of the path by using the routing information stored in the traffic engineering database TED to generate an optical layer modulation command set.

In step S106 of this embodiment, the PCE sends the optical layer modulation command set to the PCC.

In this embodiment, the optical layer modulation command set includes at least one of: code modulation shaping, spectrum shaping and dynamic damage shaping.

In this embodiment, after the PCE sends the optical layer modulation command set to the PCC, the method may further include: and the PCE receives the result of the PCC feedback for modulating or adjusting the optical module based on the optical layer modulation command set.

Through the above description of the embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware, but the former is a better implementation mode in many cases. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which is stored in a storage medium (e.g., ROM/RAM, magnetic disk, optical disk) and includes instructions for enabling a terminal device (e.g., a mobile phone, a computer, a server, or a network device) to execute the method according to the embodiments of the present invention.

In this embodiment, a path computation server (PCE) is further provided, and the PCE is used to implement the foregoing embodiments and preferred embodiments, and details of which have been already described are omitted. As used below, the term "module" may be a combination of software and/or hardware that implements a predetermined function. Although the means described in the embodiments below are preferably implemented in software, an implementation in hardware, or a combination of software and hardware is also possible and contemplated.

Example 2

Fig. 2 is a block diagram of a route calculation server according to an embodiment of the present invention, and as shown in fig. 2, the route calculation server includes:

a communication module 10, configured to receive a path computation request message sent by a PCC, and send a path computation result to the PCC;

a software defined optical module (SDO)20 for setting service transmission parameters;

and a path calculation module 30, configured to perform path calculation according to the path calculation request message and the service transmission parameter set by the SDO.

Example 3

Fig. 3 is a block diagram of a route calculation server according to an alternative embodiment of the present invention, and as shown in fig. 3, the route calculation server includes a traffic engineering database 40 in addition to all modules shown in fig. 2. The traffic engineering database 40 is used to store routing information. In this embodiment, after parsing the path computation request message, the path computation module 20 matches the service transmission parameters based on the transmission performance of the path by using the routing information stored in the traffic engineering database 40 to generate an optical layer modulation command set. In this embodiment, the optical layer modulation command set includes at least one of: code modulation shaping, spectrum shaping and dynamic damage shaping.

It should be noted that, the above modules may be implemented by software or hardware, and for the latter, the following may be implemented, but not limited to: the modules are all positioned in the same processor; alternatively, the modules are respectively located in different processors in any combination.

In order to facilitate understanding of the technical solutions provided by the present invention, the following detailed description will be made with reference to embodiments of specific scenarios.

Example 4

The embodiment provides a communication system based on the PCEP protocol standard of a software defined optical module (SDO). In this embodiment, the communication system includes: PCE, PCC, PCEP protocol and SDO.

In this embodiment, the PCE is a functional entity dedicated to path computation in the network, and based on a known network topology and constraint conditions, a best path meeting the constraint conditions is computed according to a request of the PCC, and a matching operation of service transmission parameters set by the SDO is added on the basis of an original PCE service. The PCC submits a path computation request to the PCE and obtains a path computation result; the PCEP protocol is used as a communication protocol for interaction between the PCE and the PCC, and reliable communication and flow control work based on the TCP protocol are established; based on the SDO technology, the optimal spectrum utilization rate is realized by balancing the bandwidth, distance, and complexity of the optical transmission system in which the PCC is located, and the changes of the service and the scene are better adapted, and the relevant parameters mainly for the service board card include a signal type, a modulation code type, an FEC coding error correction type, a grid width, a DSP parameter, and the like. The PCEP protocol and the software defined optical module (SDO) technology are fused, so that the method is a scheme for effectively improving the adaptive service transmission performance of the optical layer, realizing the optimal matching scheme of capacity and distance and improving the network viability.

In this embodiment, the computation models of the PCE are mainly divided into two types, one is a centralized computation model, i.e., all path computations of a given domain are completed by a centralized PCE; another is a distributed computation model, i.e., there may be multiple PCEs within a domain. For the commonality of a PCE, communication between a PCC and a PCE is unified, where the PCE-PCE interaction is handling the PCE in which the path request is sent as a PCC.

In this embodiment, the PCEP protocol may include the following stages: the process of establishing the PCEP session comprises a PCEP initialization stage, a path calculation request/response stage, a request queuing stage, an error message stage and a channel closing stage.

In this embodiment, the implementation process of the PCEP protocol may sequentially include: initialization of a PCC message, PCC packaging request message, PCC sending request message, PCE receiving request message, PCE analysis request message, path computation and PCC acceptance response message.

In this embodiment, after the PCE receives the request message, the service transmission parameters set by the SDO are transmitted to the path computation module of the PCE, and the PCE performs transmission parameter matching work to generate a specific adjustment command set in accordance with different requirements of service and scene environments. In addition, the path computation module of the PCE uses the routing information stored in the TED and other optical layer tuning algorithms to complete computation of the optimal path and the optimal spectrum utilization efficiency, and finally matches the computation path result of the optimal transmission performance of the optical transmission system where the PCC is located.

In this embodiment, the software defined optical module (SDO) enables the optical transmission component to have programmability, i.e., the optical transmission system has a variable subcarrier multiplexing scheme and modulation scheme, a variable impairment compensation algorithm, a variable FEC type and format, and a variable grid width. Through balancing bandwidth, distance and complexity, the optimal spectrum utilization efficiency is realized, and the change of services and scenes is better adapted.

In this embodiment, the SDO technology implements custom control of the optical module transmitting/receiving signals through a management and control system, and can be classified into three categories, i.e., code modulation shaping, spectrum shaping, and dynamic impairment shaping, according to different adjustment and matching modes set for service parameters. The coding modulation shaping is to select a more adaptive modulation mode and a coding mode to transmit effective information so as to realize better transmission performance; the spectrum shaping mainly considers the mismatch problem of the physical bandwidth and the transmission signal in the channel, and improves the high-frequency component or the compressed spectrum bandwidth of the signal spectrum by shaping the spectrum of the transmitting end so as to obtain better filtering resistance, feedthrough capability or crosstalk resistance; the dynamic damage shaping mainly adjusts DSP parameters of an optical module transceiver, and improves the tracking or compensating capacity of an optical module on dynamic damage (such as polarization effect, nonlinear effect and the like) in a system.

Example 5

Fig. 4 is a schematic structural diagram of a communication system based on a PCE centralized computation model. In this embodiment, a PCE centralized computation model in the PCEP protocol is taken as an example. As shown in fig. 4, the OTN management and control plane mainly includes a centralized PCE dedicated server, and the OTN device plane includes six PCC nodes, and the interconnection relationship between the nodes is as shown in the figure. The right side of the PCE special server is a PCE internal structure block diagram, and the interior of the PCE special server is mainly divided into a TED traffic engineering database, an SDO transmission parameter, a path calculation module, a PCE communication module and other related optical layer tuning algorithms. The SDO transmission parameters are specified by the service type of a user, the PCE special server is used for matching the optimal modulation code type to obtain better transmission performance, and a light emitting layer modulation command set is issued based on a PCEP protocol, and the command set is specifically executed by OTN equipment.

Fig. 5 shows a basic communication model based on PCC/PCE in PCEP protocol. As shown in fig. 5, the process of establishing the PCEP session mainly includes the following stages.

An initialization stage: the first step is the establishment process of TCP connection, namely three-way handshake is carried out between PCC and PCE, the second step is that a PCEP channel is established based on the TCP connection, and then Open message establishment session and Keepalive message maintenance session are sent;

path computation request/response phase: the PCC sends a path computation request, namely a PCReq message to the PCE, and when the PCE receives information carried in the PCReq message and TED (traffic engineering database, which stores information required by the PCE for path computation) and LSP-DB (label switched path database) information stored in the PCE, the PCE performs path computation;

a request queuing stage: when a large number of service requests are sent to the PCE, a PCC queuing waiting phenomenon exists according to different priorities, if the response time is too long, the PCE sends a PCNtf message to the PCC to inform the PCC of the waiting time, and after the PCC receives the message, the PCC determines whether to finish the path calculation request and sends the request to other PCEs through a series of judgments;

an error message stage: when the message is transmitted in the PCEP channel, an error that the PCE cannot identify may occur, and then the PCE sends a PCErr message to the PCC to prompt a protocol error, or notifies the PCC when the computation capability of the PCE is insufficient; in the channel closing stage, after the PCC receives the path computation request response sent by the PCE and no other service request exists, the PCC sends Close information to Close the channel and then disconnects the TCP connection.

Fig. 6 is a block diagram of a PCEP protocol + SDO implementation design in accordance with an embodiment of the present invention. As shown in fig. 6, the process is roughly divided into initializing a PCC message, where the PCC needs to send related information of a source node, a destination node, a path, an exchange granularity, a bandwidth, and the like of a route to a PCE, so that the PCE completes initialization setting of request information; the PCC packages the request message, and packages and sends the message after the message is initialized; the PCC sends a request message, and sends the packaged message to the PCE through Socket programming based on the TCP protocol; the PCE receives the request message, and after the message is sent to the PCE, the PCE receives the message through the communication module; the PCE analyzes the request message, and after receiving the message, the PCE unpacks and analyzes the message; after receiving the message, the PCE module utilizes the routing information stored in the TED, the introduced SDO to set transmission parameters, other optical layer tuning algorithms and the like to complete the calculation of the optimal path and the optimal spectrum utilization efficiency, thereby completing the relevant content of PCE service broadening and finally matching the optimal transmission performance message; returning the final path calculation result message to the PCC through the processes of initialization, packaging and sending; and the PCC receives the response message, receives the related path calculation result and various messages returned by the PCE package, and reads the response message.

In this embodiment, the transmission parameter reconfiguration operation of the SDO may be performed. That is, for the path structure of the transport layer where the PCC is located, the SDO selects different modulation methods according to its own requirements to meet the requirements for transmission distance and spectral efficiency in different application scenarios.

Fig. 7 shows all the parameter contents of the service board based on the SDO technology according to the embodiment of the present invention. As shown in fig. 7, the transmitted signal types can be divided into various super 100G signals such as 100G, 200G, 400G, 1T, etc., the FEC coding redundancy can be adjusted to 0, 20%, 40%, 60%, etc., the modulation methods include BPSK, QPSK, 8QAM, 16QAM, etc., the DSP parameters include pulse shaping, fiber CD, self-phase modulation (SPM), etc., and the grid width multi-step (37.5GHZ,50GHZ,100GHZ, etc.) adjustable modes, etc.

In this embodiment, the SDO implements user-defined control on the optical module transmitting/receiving signals through a management and control system, and may be classified into three categories, i.e., code modulation shaping, spectrum shaping, and dynamic impairment shaping, according to different adjustment modes set for service parameters.

Example 6

In the present embodiment, a coded modulation shaping adjustment method is described as an example.

The coded modulation shaping is to select a more adaptive modulation mode and coding mode to transmit effective information so as to realize better transmission performance. The currently common coding and shaping technology mainly comprises four types, namely error correction coding and shaping, hybrid modulation, probability shaping and geometric shaping. The long-distance coherent optical module at the line side in the existing product comprises a plurality of service rates, a plurality of coding modes and a plurality of FEC coding modes with different expenses. For example, at a specific service rate, higher noise tolerance or longer transmission distance can be obtained by using a low-order modulation code pattern or high-overhead FEC coding, and higher spectral efficiency and better networking punch-through capability can be obtained by using a high-order modulation code pattern or low-overhead FEC coding. Therefore, for a service with a specific rate, different modulation code types and coding modes are adopted, and the optical module OSNR threshold, filtering cost, nonlinear cost and the like of a system link of the service are different, so that the optical transmission service has different transmission performances. The coding modulation shaping is to select a proper modulation code pattern and a coding mode through a manual selection or automatic adjustment algorithm so as to meet the requirements of specific services and scenes.

Optimizing and applying one: in a long-distance transmission scene, the SDO coding modulation shaping function can be adopted to optimize the optical transmission performance. Under the condition of a specific optical route and a specific service rate, according to the link information of the selected route, such as the optical fiber type, the span loss, the channel interval, the line side optical module type, the OA model and the like, the optimal coding modulation configuration meeting the transmission performance of the link, namely the relevant transmission parameters of the service board card, is selected and configured, and the optimal OSNR margin is obtained to ensure the long-term stability of the system.

Fig. 8 is an SDO optimization process in a long-distance transmission scenario. As shown in fig. 8, the flow is as follows:

(1) the user establishes service according to various link information of the optical layer equipment to specify the signal type, the modulation code type and other related contents.

(2) The PCC establishes a communication link with the PCE based on the PCEP protocol.

(3) And the PCE matches the optimal modulation code pattern under the constraint of the maximum transmission distance of a user according to the transmission parameters set by the SDO, so that better optical path performance is obtained, and a specific coding modulation command set is generated. The modulation code pattern of the optical module supports traditional modulation code patterns such as BPSK, QPSK, 8QAM, 16QAM, 32QAM, 64QAM and the like, and in order to achieve the scene of long-distance transmission, a mixed modulation code pattern of time sequence interleaving is adopted. Therefore, when calculating the route by the SDO, the mixed modulation table needs to be traversed according to the order of the large rate, the low spectral width to the low rate, and the high spectral width, to determine a possible mixed modulation type list for calculating the service route, and if all list items try to return no available route calculation result, the next optimal route is calculated. Under different mixed modulation modes, the channel bandwidth, the signal spectrum efficiency and the OSNR tolerance are all different, taking 200G/27% FEC mixed modulation as an example, the OSNR and baud rate data under different frequency spectrums are shown in table 1.

TABLE 1

OSNR margin (dB)	Baud rate (GHz)	Spectral efficiency	Mixing ratio of
				13.10	69.44	2	128:0
13.13	68.90	2.015625	126:2
				13.16	68.63	2.0234375	125:3
13.19	68.10	2.0390625	123:5
				13.22	67.59	2.0546875	121:7
13.25	67.08	2.0703125	119:9
				13.28	66.57	2.0859375	117:11
13.30	66.08	2.1015625	115:13
				13.33	65.59	2.1171875	113:15
13.36	65.11	2.1328125	111:17
				13.74	61.08	2.2734375	93:35
....	....	....	....

(4) And the PCE communication module issues a light layer adjustment command set.

(5) The optical layer device performs specific modulation.

(6) And feeding the modulation result back to the PCE.

In this embodiment, by implementing flexible switching of the coded modulation, the transmission capability and the transmission feasibility of the system can be maximized, thereby improving the space for path selection. For the path selection of the SDN controller, the available paths are no longer limited to fixed code modulated network resources, but become dynamically variable code modulated network resources. The method has the advantages that the modulation mode is changed into modulation according to requirements, the intelligent level of the network is greatly improved, the bearing capacity is maximized, and the service recovery capacity is improved.

Example 7

In this embodiment, a spectral shaping adjustment method is described as an example.

The spectral shaping mainly considers the mismatch between the physical bandwidth in the channel and the transmission signal, which results in severe signal attenuation and thus brings a filtering damage cost. Therefore, the high-frequency component of the signal spectrum or the compressed spectral bandwidth can be improved by shaping the spectrum of the emission end, so as to obtain better anti-filtering characteristic, feedthrough capability or anti-crosstalk capability. The main adjustment ways for spectral shaping are currently spectral pre-emphasis and nyquist shaping. In the OADM/ROADM cascade scenario, the system may have severe optical filtering effects. The deeper the pre-emphasis or the higher the nyquist shaping compression in this scenario, the stronger the signal light feedthrough performance. However, the spectral shaping may affect the OSNR threshold of the optical module, and the bandwidth and the transmission distance of the link filter need to be considered comprehensively to select the spectral shaping scheme with the best overall performance.

In this embodiment, an example is given in which an optimized application two, that is, in an OADM/ROADM cascade networking scenario, an SDO spectrum shaping scheme is used to improve the service pass-through capability.

In this embodiment, SDO spectral shaping requires the SDN controller to set according to the number of cascades of optical filters in the link and the bandwidth. And the light module under the scene realizes the originating spectrum shaping, obtains better punch-through performance and realizes the self-adaptive optimization application of the light layer. Based on the feasibility and the simple controllability of the technical implementation, the SDO spectrum shaping scheme at the present stage is mainly a Nyquist shaping scheme. Then the spectral shaping part strategy of the existing optical module capable of supporting the nyquist shaping function under different application scenarios is shown in table 2.

TABLE 2

As shown in fig. 9, the optimized application scenario in the OADM/ROADM cascaded networking scenario is shown. The process is as follows:

(1) and (3) verifying filtering damage during service expansion, and when the filtering cost of the system is out of limit, frequency spectrum shaping is required to deal with the filtering damage of the system. The user performs a spectral shaping coping system filter impairment scheme.

(3) And the PCE adopts a spectrum shaping scheme to the optical module and generates a specific adjusting command set according to the requirement that the modulation code type, the service rate and the link power are not changed. According to the spectrum shaping strategy table, the normal application state of the Nyquist shaping function in the hardware optical module can be ensured by setting the service rate, the modulation code pattern, the FEC overhead and the channel interval data matching fixed parameter values.

(5) The optical layer device performs specific tuning.

(6) And feeding the adjustment result back to the PCE.

In this embodiment, the main purpose of nyquist spectral shaping is to compress the spectral width and improve the spectral utilization. This function is not in conflict with the SDO coded modulation shaping function in the last application scenario. Under the scene of new service construction and dynamic recovery, the Nyquist shaping function and the coding modulation shaping function can be directly and jointly applied.

Example 8

In the present embodiment, a dynamic lesion reshaping adjustment method is described as an example.

The dynamic damage shaping mainly adjusts DSP parameters of an optical module transceiver, and improves the tracking or compensating capacity of an optical module on dynamic damage (such as polarization effect, nonlinear effect and the like) in a system. The dynamic damage shaping mainly deals with the real-time variable optical damage during the service optical transmission, in the existing long-distance optical transmission system, the optical damage includes the Polarization Mode Dispersion (PMD), the polarization state deflection (SOP), the fiber nonlinear interference and the laser phase noise, etc., the polarization mode dispersion and the phase noise in the actual system can be almost completely compensated without sacrificing other performance indexes of the optical module, and the SOP damage and the nonlinear damage can dynamically adjust the DSP parameters to improve. These parameters require a reasonable configuration that integrates the link optical damage level and the OSNR margin performance degradation of the optical module itself.

In this embodiment, a description is given by taking an example of optimizing application three, that is, suppressing nonlinear damage of an optical path by using a transmit-side dispersion pre-compensation function in dynamic damage shaping, and improving transmission performance of a system.

In this embodiment, the SDN controller may configure a more accurate dispersion pre-compensation amount and suppress nonlinear damage of a link according to the fiber type, the fiber length, and the fiber input power distribution of the link through a dynamic damage shaping algorithm without changing the modulation format, the service rate, and the like of the existing optical path, so as to improve the transmission performance of the system. And the preset value of the dispersion pre-compensation quantity is related to the type of the optical fiber and the power distribution of the link.

As shown in fig. 10, a dispersion pre-compensation application scenario is shaped for the SDO spectrum. The process is as follows:

(1) and (3) the user judges whether a dispersion pre-compensation scheme needs to be executed or not according to the actual scene (optical fiber type, loss, fiber-entering power and the like) of the link by combining the nonlinear damage verification result.

(3) And the PCE adjusts the optical module according to the requirement of executing the dispersion pre-compensation scheme and generates a specific adjustment command set. Setting DSP executable parameters according to a configuration strategy of a sending end precompensation dispersion function in the optical module, and sending the parameters

The normal application state of the dispersion precompensation working mode in the hardware optical module can be ensured.

(4) And the PCE communication module sends an optical layer code modulation command set.

(5) The optical module in the optical layer device is switched to a dispersion pre-compensation working mode.

(6) And feeding the adjustment result back to the PCE.

An embodiment of the present invention further provides a computer-readable storage medium, in which a computer program is stored, wherein the computer program is configured to perform the steps in any of the above method embodiments when executed.

In an exemplary embodiment, the computer-readable storage medium may include, but is not limited to: various media capable of storing computer programs, such as a usb disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic disk, or an optical disk.

Embodiments of the present invention also provide an electronic device comprising a memory having a computer program stored therein and a processor arranged to run the computer program to perform the steps of any of the above method embodiments.

In an exemplary embodiment, the electronic apparatus may further include a transmission device and an input/output device, wherein the transmission device is connected to the processor, and the input/output device is connected to the processor.

For specific examples in this embodiment, reference may be made to the examples described in the above embodiments and exemplary embodiments, and details of this embodiment are not repeated herein.

It will be apparent to those skilled in the art that the various modules or steps of the invention described above may be implemented using a general purpose computing device, they may be centralized on a single computing device or distributed across a network of computing devices, and they may be implemented using program code executable by the computing devices, such that they may be stored in a memory device and executed by the computing device, and in some cases, the steps shown or described may be performed in an order different than that described herein, or they may be separately fabricated into various integrated circuit modules, or multiple ones of them may be fabricated into a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A path computation method, comprising:

a path computation server (PCE) receives a path computation request message sent by a path computation request client (PCC);

the PCE carries out path calculation according to the path calculation request message and service transmission parameters set by the SDO;

and the PCE sends the path calculation result to the PCC.

2. The method according to claim 1, wherein before the PCE receives the path computation request message sent by the PCC, the method further comprises:

the PCE establishes a communication link with the PCC based on a path computation element communication protocol PCEP.

3. The method of claim 1, wherein before the PCE performs the path computation according to the path computation request message and the service transmission parameters set by the SDO, the method further comprises:

and setting the service transmission parameters in the SDO according to service transmission scenes.

4. The method of claim 1, wherein the traffic transmission parameters comprise at least one of: signal type, modulation code type, FEC coding error correction type, grid width, DSP parameters.

5. The method as claimed in claim 1, wherein the PCE performs path computation according to the path computation request message and the service transmission parameters set by the SDO, including:

and the PCE analyzes the path computation request message, and utilizes routing information stored in a Traffic Engineering Database (TED) to match the service transmission parameters based on the transmission performance of the path so as to generate an optical layer modulation command set.

6. The method of claim 1, wherein the PCE sending path computation results to the PCC comprises:

the PCE sends the set of optical layer modulation commands to the PCC.

7. The method of claim 6, wherein the optical layer modulation command set comprises at least one of: code modulation shaping, spectrum shaping and dynamic damage shaping.

8. The method of claim 6, wherein after the PCE sends the optical layer modulation command set to the PCC, the method further comprises:

and the PCE receives the result of the PCC feedback for modulating or adjusting the optical module based on the optical layer modulation command set.

9. A computation path server, PCE, comprising:

the communication module is used for receiving a path calculation request message sent by a PCC (policy and charging control) client and sending a path calculation result to the PCC;

the software defined optical module SDO is used for setting service transmission parameters;

and the path calculation module is used for calculating the path according to the path calculation request message and the service transmission parameters set by the SDO.

10. The PCE of claim 9, wherein,

the communication module is further configured to establish a communication link with the PCC based on a path computation element communication protocol PCEP.

11. The PCE of claim 9, wherein the traffic transmission parameters include at least one of: signal type, modulation code type, FEC coding error correction type, grid width, DSP parameters.

12. The PCE of claim 9, further comprising:

a traffic engineering database TED for storing routing information;

the path computation module is further configured to parse the path computation request message, and match the service transmission parameters based on the transmission performance of the path by using the routing information stored in the TED to generate an optical layer modulation command set.

13. The PCE of claim 12, wherein the optical layer modulation command set includes at least one of: code modulation shaping, spectrum shaping and dynamic damage shaping.

14. The method of claim 12,

the communication module is further configured to receive a result of the PCC feedback for modulating or adjusting an optical module based on the optical layer modulation command set.

15. A communication system based on a path computation element communication protocol PCEP, comprising one or more computation server PCEs as claimed in any of claims 9 to 14, and one or more computation request clients PCC, wherein the PCEs and PCCs interact based on the PCEP protocol.

16. The communication system of claim 15, wherein the path computation model for the PCE comprises: a centralized computation model of one PCE control or a distributed computation model of multiple PCE controls.

17. A computer-readable storage medium, in which a computer program is stored, which computer program, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 8.

18. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the steps of the method as claimed in any of claims 1 to 8 are implemented when the computer program is executed by the processor.