# US 2013/0156428 A1 · System and Method for Impairment-Aware Routing and Wavelength Assignment in Wavelength Switched Optical Networks > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0156428 A1 - Document ID: US20130156428A1 - Status: Published application - Kind: A1 - Application number: 13/762,905 - Filed: 2013-02-08 - Published: 2013-06-20 - Earliest claimed: 2009-02-06 - Assignees: Futurewei Technologies, Inc. - Inventors: Young Lee; Greg Bernstein - Web page: https://patentgrep.com/patent/US20130156428A1 ## CPC - H04J 14/0267: {Optical signaling or routing} - H04J 14/0256: {at the optical channel layer} - H04J 14/0257: {Wavelength assignment algorithms} - H04J 14/0258: {Wavelength identification or labelling} - H04J 14/0271: {Impairment aware routing} - H04Q 11/0062: {Network aspects} - H04J 14/0269: {using tables for routing} - H04Q 2011/0073: {Provisions for forwarding or routing, e.g. lookup tables} - H04Q 2011/0086: {Network resource allocation, dimensioning or optimisation} - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W) ## Abstract An apparatus comprising a path computation element (PCE) configured for at least partial impairment aware routing and wavelength assignment (RWA) and to communicate with a path computation client (PCC) based on a PCE protocol (PCEP) that supports path routing, wavelength assignment (WA), and impairment validation (IV). Also disclosed is a network component comprising at least one processor configured to implement a method comprising establishing a PCEP session with a PCC, receiving path computation information comprising RWA information and constraints from the PCC, establishing impairment aware RWA (IA-RWA) based on the path computation information and a private impairment information for a vendor's equipment, and sending a path and an assigned wavelength based on the IA-RWA to the PCC. Disclosed is a method comprising establishing impairment aware routing and wavelength assignment for a plurality of network elements (NEs) in an optical network using routing and combined WA and IV. ## Claims ### Claim 1 A network comprising: a set of two or more path computation elements (PCEs) configured to perform an impairment aware (IA) routing wavelength assignment (RWA) process by cooperating via a PCE communication protocol (PCEP). ### Claim 2 (depends on 1) The network of claim 1, wherein routing, wavelength assignment, and impairment validation are separately performed by three PCEs. ### Claim 3 (depends on 1) The network of claim 1, wherein a combined wavelength assignment and impairment validation process is performed by a first PCE, and wherein a separate routing process is performed by a second PCE. ### Claim 4 (depends on 1) The network of claim 1, wherein a combined routing and wavelength assignment process is performed by a first PCE, and wherein a separate impairment validation process is performed by a second PCE. ### Claim 5 (depends on 1) The network of claim 1, wherein an RWA process is performed before an associated impairment validation (IV) process. ### Claim 6 (depends on 5) The network of claim 5, wherein the IV process renders a yes/no decision on a path and wavelength selected by the RWA process. ### Claim 7 (depends on 1) The network of claim 1, wherein an impairment validation (IV) process is performed before an associated RWA process. ### Claim 8 (depends on 7) The network of claim 7, wherein the IV process furnishes a list of routes and wavelengths to the RWA process, and wherein the routes and wavelengths are valid with respect to impairments. ### Claim 9 (depends on 1) The network of claim 1, wherein a combined RWA and approximate impairment validation (IV) process is performed by a first PCE, and wherein a separate detailed impairment validation process is performed by a second PCE. ### Claim 10 (depends on 1) The network of claim 1, wherein a combined RWA process is performed by a first PCE, wherein a separate approximate impairment validation (IV) is performed by a second PCE, and wherein a separate detailed impairment validation process is performed by a third PCE. ### Claim 11 A method comprising: receiving, by a path computation element (PCE), a message from a path computation client (PCC) requesting that a path computation be performed, wherein the message requests that the computed path meet specified quality constraints between two nodes; sending a request for candidate paths between the two nodes and associated acceptable wavelengths to an impairment validation (IV)-Candidates PCE; receiving a list of paths and wavelengths from the IV-Candidates PCE; and using the paths and the wavelengths as input for a routing and wavelength assignment (RWA) computation. ### Claim 12 (depends on 11) The method of claim 11 further comprising returning an impairment aware RWA (IA-RWA) computation result to the PCC. ### Claim 13 (depends on 11) The method of claim 11 further comprising sending a request to an IV-Detailed PCE for a detailed verification of a path and wavelength computed by the PCE. ### Claim 14 (depends on 13) The method of claim 13 further comprising receiving, from the IV-Detailed PCE, the results of a validation of the path and wavelength as computed by the PCE. ### Claim 15 (depends on 14) The method of claim 14 further comprising returning the final results of an impairment aware RWA (IA-RWA) to the PCC. ### Claim 16 A method comprising: receiving, by a path computation element (PCE), a message from a path computation client (PCC) requesting that a path computation be performed, wherein the message requests that the computed path meet specified quality constraints between two nodes; computing a network path between the two nodes; and distributing an impairment validation process for the network path among the nodes along the path. ### Claim 17 (depends on 16) The method of claim 16, wherein degradation measures are accumulated along the path via signaling. ### Claim 18 (depends on 17) The method of claim 17, wherein a decision on impairment validity of the path is made when the accumulated measures reach a destination node. ### Claim 19 (depends on 18) The method of claim 18 further comprising distributing wavelength assignment at the same time as distributed impairment validation. ### Claim 20 (depends on 18) The method of claim 18, wherein impairment related information for all wavelengths that could be used is accumulated.