pce/src/main/java/org/opendaylight/transportpce/pce/graph/PostAlgoPathValidator.java

   1 /*
   2  * Copyright © 2017 AT&T, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8
   9 package org.opendaylight.transportpce.pce.graph;
  10
  11 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  12 import java.math.RoundingMode;
  13 import java.util.ArrayList;
  14 import java.util.Arrays;
  15 import java.util.BitSet;
  16 import java.util.Collections;
  17 import java.util.HashMap;
  18 import java.util.List;
  19 import java.util.Map;
  20 import org.jgrapht.GraphPath;
  21 import org.opendaylight.transportpce.common.ResponseCodes;
  22 import org.opendaylight.transportpce.common.StringConstants;
  23 import org.opendaylight.transportpce.common.fixedflex.GridConstant;
  24 import org.opendaylight.transportpce.common.fixedflex.GridUtils;
  25 import org.opendaylight.transportpce.pce.constraints.PceConstraints;
  26 import org.opendaylight.transportpce.pce.constraints.PceConstraints.ResourcePair;
  27 import org.opendaylight.transportpce.pce.networkanalyzer.PceNode;
  28 import org.opendaylight.transportpce.pce.networkanalyzer.PceResult;
  29 import org.opendaylight.yang.gen.v1.http.org.opendaylight.transportpce.pce.rev220615.SpectrumAssignment;
  30 import org.opendaylight.yang.gen.v1.http.org.opendaylight.transportpce.pce.rev220615.SpectrumAssignmentBuilder;
  31 import org.opendaylight.yang.gen.v1.http.org.openroadm.network.types.rev211210.OpenroadmLinkType;
  32 import org.opendaylight.yang.gen.v1.http.org.openroadm.otn.common.types.rev181130.OpucnTribSlotDef;
  33 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.network.rev180226.NodeId;
  34 import org.opendaylight.yangtools.yang.common.Uint16;
  35 import org.slf4j.Logger;
  36 import org.slf4j.LoggerFactory;
  37
  38 public class PostAlgoPathValidator {
  39     /* Logging. */
  40     private static final Logger LOG = LoggerFactory.getLogger(PostAlgoPathValidator.class);
  41
  42     private static final double MIN_OSNR_W100G = 17;
  43     private static final double TRX_OSNR = 33;
  44     private static final double ADD_OSNR = 30;
  45     public static final Long CONST_OSNR = 1L;
  46     public static final double SYS_MARGIN = 0;
  47
  48     @SuppressWarnings("fallthrough")
  49     @SuppressFBWarnings(
  50         value = "SF_SWITCH_FALLTHROUGH",
  51         justification = "intentional fallthrough")
  52     public PceResult checkPath(GraphPath<String, PceGraphEdge> path, Map<NodeId, PceNode> allPceNodes,
  53         PceResult pceResult, PceConstraints pceHardConstraints, String serviceType) {
  54
  55         // check if the path is empty
  56         if (path.getEdgeList().isEmpty()) {
  57             pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
  58             return pceResult;
  59         }
  60         int spectralWidthSlotNumber = GridConstant.SPECTRAL_WIDTH_SLOT_NUMBER_MAP
  61             .getOrDefault(serviceType, GridConstant.NB_SLOTS_100G);
  62         SpectrumAssignment spectrumAssignment = null;
  63         //variable to deal with 1GE (Nb=1) and 10GE (Nb=10) cases
  64         switch (serviceType) {
  65             case StringConstants.SERVICE_TYPE_OTUC2:
  66             case StringConstants.SERVICE_TYPE_OTUC3:
  67             case StringConstants.SERVICE_TYPE_OTUC4:
  68             case StringConstants.SERVICE_TYPE_400GE:
  69                 spectralWidthSlotNumber = GridConstant.SPECTRAL_WIDTH_SLOT_NUMBER_MAP
  70                     .getOrDefault(serviceType, GridConstant.NB_SLOTS_400G);
  71             //fallthrough
  72             case StringConstants.SERVICE_TYPE_100GE_T:
  73             case StringConstants.SERVICE_TYPE_OTU4:
  74                 spectrumAssignment = getSpectrumAssignment(path, allPceNodes, spectralWidthSlotNumber);
  75                 pceResult.setServiceType(serviceType);
  76                 if (spectrumAssignment.getBeginIndex().equals(Uint16.valueOf(0))
  77                         && spectrumAssignment.getStopIndex().equals(Uint16.valueOf(0))) {
  78                     pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
  79                     pceResult.setLocalCause(PceResult.LocalCause.NO_PATH_EXISTS);
  80                     return pceResult;
  81                 }
  82                 if (spectrumAssignment.getFlexGrid()) {
  83                     LOG.info("Spectrum assignment flexgrid mode");
  84                     pceResult.setResultWavelength(GridConstant.IRRELEVANT_WAVELENGTH_NUMBER);
  85                 } else {
  86                     LOG.info("Spectrum assignment fixedgrid mode");
  87                     pceResult.setResultWavelength(
  88                             GridUtils.getWaveLengthIndexFromSpectrumAssigment(spectrumAssignment.getBeginIndex()
  89                                 .toJava()));
  90                 }
  91                 pceResult.setMinFreq(GridUtils.getStartFrequencyFromIndex(spectrumAssignment.getBeginIndex().toJava()));
  92                 pceResult.setMaxFreq(GridUtils.getStopFrequencyFromIndex(spectrumAssignment.getStopIndex().toJava()));
  93                 LOG.info("In PostAlgoPathValidator: spectrum assignment found {} {}", spectrumAssignment, path);
  94
  95                 // Check the OSNR
  96                 if (!checkOSNR(path)) {
  97                     pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
  98                     pceResult.setLocalCause(PceResult.LocalCause.OUT_OF_SPEC_OSNR);
  99                     return pceResult;
 100                 }
 101
 102                 // Check if MaxLatency is defined in the hard constraints
 103                 if ((pceHardConstraints.getMaxLatency() != -1)
 104                         && (!checkLatency(pceHardConstraints.getMaxLatency(), path))) {
 105                     pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
 106                     pceResult.setLocalCause(PceResult.LocalCause.TOO_HIGH_LATENCY);
 107                     return pceResult;
 108                 }
 109
 110                 // Check if nodes are included in the hard constraints
 111                 if (!checkInclude(path, pceHardConstraints)) {
 112                     pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
 113                     pceResult.setLocalCause(PceResult.LocalCause.HD_NODE_INCLUDE);
 114                     return pceResult;
 115                 }
 116
 117                 // TODO here other post algo validations can be added
 118                 // more data can be sent to PceGraph module via PceResult structure if required
 119
 120                 pceResult.setRC(ResponseCodes.RESPONSE_OK);
 121                 pceResult.setLocalCause(PceResult.LocalCause.NONE);
 122                 break;
 123             case StringConstants.SERVICE_TYPE_100GE_M:
 124             case StringConstants.SERVICE_TYPE_10GE:
 125             case StringConstants.SERVICE_TYPE_1GE:
 126                 Map<String, Integer> tribSlotNbMap = Map.of(
 127                     StringConstants.SERVICE_TYPE_100GE_M, 20,
 128                     StringConstants.SERVICE_TYPE_10GE, 8,
 129                     StringConstants.SERVICE_TYPE_1GE, 1);
 130                 int tribSlotNb = tribSlotNbMap.get(serviceType);
 131                 pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
 132                 pceResult.setServiceType(serviceType);
 133                 Map<String, List<Uint16>> tribSlot = chooseTribSlot(path, allPceNodes, tribSlotNb);
 134                 Map<String, Uint16> tribPort = chooseTribPort(path, allPceNodes, tribSlot, tribSlotNb);
 135                 List<OpucnTribSlotDef> resultTribPortTribSlot = getMinMaxTpTs(tribPort, tribSlot);
 136
 137                 if (resultTribPortTribSlot.get(0) != null && resultTribPortTribSlot.get(1) != null) {
 138                     pceResult.setResultTribPortTribSlot(resultTribPortTribSlot);
 139                     pceResult.setRC(ResponseCodes.RESPONSE_OK);
 140                     LOG.info("In PostAlgoPathValidator: found TribPort {} - tribSlot {} - tribSlotNb {}",
 141                         tribPort, tribSlot, tribSlotNb);
 142                 }
 143                 break;
 144             case StringConstants.SERVICE_TYPE_ODU4:
 145             case StringConstants.SERVICE_TYPE_ODUC2:
 146             case StringConstants.SERVICE_TYPE_ODUC3:
 147             case StringConstants.SERVICE_TYPE_ODUC4:
 148             case StringConstants.SERVICE_TYPE_100GE_S:
 149                 pceResult.setRC(ResponseCodes.RESPONSE_OK);
 150                 pceResult.setServiceType(serviceType);
 151                 LOG.info("In PostAlgoPathValidator: ODU4/ODUCn path found {}", path);
 152                 break;
 153             default:
 154                 pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
 155                 LOG.warn("In PostAlgoPathValidator checkPath: unsupported serviceType {} found {}",
 156                     serviceType, path);
 157                 break;
 158         }
 159         return pceResult;
 160     }
 161
 162     // Check the latency
 163     private boolean checkLatency(Long maxLatency, GraphPath<String, PceGraphEdge> path) {
 164         double latency = 0;
 165
 166         for (PceGraphEdge edge : path.getEdgeList()) {
 167             if (edge.link() == null || edge.link().getLatency() == null) {
 168                 LOG.warn("- In checkLatency: the link {} does not contain latency field",
 169                     edge.link().getLinkId().getValue());
 170                 return false;
 171             }
 172             latency += edge.link().getLatency();
 173             LOG.debug("- In checkLatency: latency of {} = {} units", edge.link().getLinkId().getValue(), latency);
 174         }
 175         return (latency < maxLatency);
 176     }
 177
 178     // Check the inclusion if it is defined in the hard constraints
 179     private boolean checkInclude(GraphPath<String, PceGraphEdge> path, PceConstraints pceHardConstraintsInput) {
 180         List<ResourcePair> listToInclude = pceHardConstraintsInput.getListToInclude();
 181         if (listToInclude.isEmpty()) {
 182             return true;
 183         }
 184
 185         List<PceGraphEdge> pathEdges = path.getEdgeList();
 186         LOG.debug(" in checkInclude vertex list: [{}]", path.getVertexList());
 187
 188         List<String> listOfElementsSubNode = new ArrayList<>();
 189         listOfElementsSubNode.add(pathEdges.get(0).link().getsourceNetworkSupNodeId());
 190         listOfElementsSubNode.addAll(listOfElementsBuild(pathEdges, PceConstraints.ResourceType.NODE,
 191             pceHardConstraintsInput));
 192
 193         List<String> listOfElementsCLLI = new ArrayList<>();
 194         listOfElementsCLLI.add(pathEdges.get(0).link().getsourceCLLI());
 195         listOfElementsCLLI.addAll(listOfElementsBuild(pathEdges, PceConstraints.ResourceType.CLLI,
 196             pceHardConstraintsInput));
 197
 198         List<String> listOfElementsSRLG = new ArrayList<>();
 199         // first link is XPONDEROUTPUT, no SRLG for it
 200         listOfElementsSRLG.add("NONE");
 201         listOfElementsSRLG.addAll(listOfElementsBuild(pathEdges, PceConstraints.ResourceType.SRLG,
 202             pceHardConstraintsInput));
 203
 204         // validation: check each type for each element
 205         for (ResourcePair next : listToInclude) {
 206             int indx = -1;
 207             switch (next.getType()) {
 208                 case NODE:
 209                     if (listOfElementsSubNode.contains(next.getName())) {
 210                         indx = listOfElementsSubNode.indexOf(next.getName());
 211                     }
 212                     break;
 213                 case SRLG:
 214                     if (listOfElementsSRLG.contains(next.getName())) {
 215                         indx = listOfElementsSRLG.indexOf(next.getName());
 216                     }
 217                     break;
 218                 case CLLI:
 219                     if (listOfElementsCLLI.contains(next.getName())) {
 220                         indx = listOfElementsCLLI.indexOf(next.getName());
 221                     }
 222                     break;
 223                 default:
 224                     LOG.warn(" in checkInclude vertex list unsupported resource type: [{}]", next.getType());
 225             }
 226
 227             if (indx < 0) {
 228                 LOG.debug(" in checkInclude stopped : {} ", next.getName());
 229                 return false;
 230             }
 231
 232             LOG.debug(" in checkInclude next found {} in {}", next.getName(), path.getVertexList());
 233
 234             listOfElementsSubNode.subList(0, indx).clear();
 235             listOfElementsCLLI.subList(0, indx).clear();
 236             listOfElementsSRLG.subList(0, indx).clear();
 237         }
 238
 239         LOG.info(" in checkInclude passed : {} ", path.getVertexList());
 240         return true;
 241     }
 242
 243     private List<String> listOfElementsBuild(List<PceGraphEdge> pathEdges, PceConstraints.ResourceType type,
 244         PceConstraints pceHardConstraints) {
 245
 246         List<String> listOfElements = new ArrayList<>();
 247         for (PceGraphEdge link : pathEdges) {
 248             switch (type) {
 249                 case NODE:
 250                     listOfElements.add(link.link().getdestNetworkSupNodeId());
 251                     break;
 252                 case CLLI:
 253                     listOfElements.add(link.link().getdestCLLI());
 254                     break;
 255                 case SRLG:
 256                     if (link.link().getlinkType() != OpenroadmLinkType.ROADMTOROADM) {
 257                         listOfElements.add("NONE");
 258                         break;
 259                     }
 260                     // srlg of link is List<Long>. But in this algo we need string representation of
 261                     // one SRLG
 262                     // this should be any SRLG mentioned in include constraints if any of them if
 263                     // mentioned
 264                     boolean found = false;
 265                     for (Long srlg : link.link().getsrlgList()) {
 266                         String srlgStr = String.valueOf(srlg);
 267                         if (pceHardConstraints.getSRLGnames().contains(srlgStr)) {
 268                             listOfElements.add(srlgStr);
 269                             LOG.info("listOfElementsBuild. FOUND SRLG {} in link {}", srlgStr, link.link());
 270                             found = true;
 271                         }
 272                     }
 273                     if (!found) {
 274                         // there is no specific srlg to include. thus add to list just the first one
 275                         listOfElements.add("NONE");
 276                     }
 277                     break;
 278                 default:
 279                     LOG.debug("listOfElementsBuild unsupported resource type");
 280             }
 281         }
 282         return listOfElements;
 283     }
 284
 285     private Map<String, Uint16> chooseTribPort(GraphPath<String,
 286         PceGraphEdge> path, Map<NodeId, PceNode> allPceNodes, Map<String, List<Uint16>> tribSlotMap, int nbSlot) {
 287         LOG.info("In choosetribPort: edgeList = {} ", path.getEdgeList());
 288         Map<String, Uint16> tribPortMap = new HashMap<>();
 289
 290         for (PceGraphEdge edge : path.getEdgeList()) {
 291             NodeId linkSrcNode = edge.link().getSourceId();
 292             String linkSrcTp = edge.link().getSourceTP().getValue();
 293             NodeId linkDestNode = edge.link().getDestId();
 294             String linkDestTp = edge.link().getDestTP().getValue();
 295             PceNode pceOtnNodeSrc = allPceNodes.get(linkSrcNode);
 296             PceNode pceOtnNodeDest = allPceNodes.get(linkDestNode);
 297             List<Uint16> srcTpnPool = pceOtnNodeSrc.getAvailableTribPorts().get(linkSrcTp);
 298             List<Uint16> destTpnPool = pceOtnNodeDest.getAvailableTribPorts().get(linkDestTp);
 299             List<Uint16> commonEdgeTpnPool = new ArrayList<>();
 300             for (Uint16 srcTpn : srcTpnPool) {
 301                 if (destTpnPool.contains(srcTpn)) {
 302                     commonEdgeTpnPool.add(srcTpn);
 303                 }
 304             }
 305
 306             if (!commonEdgeTpnPool.isEmpty()) {
 307                 Integer startTribSlot = tribSlotMap.values().stream().findFirst().get().get(0).toJava();
 308                 Integer tribPort = (int) Math.ceil((double)startTribSlot / nbSlot);
 309                 for (Uint16 commonTribPort : commonEdgeTpnPool) {
 310                     if (tribPort.equals(commonTribPort.toJava())) {
 311                         tribPortMap.put(edge.link().getLinkId().getValue(), commonTribPort);
 312                     }
 313                 }
 314             }
 315         }
 316         tribPortMap.forEach((k,v) -> LOG.info("TribPortMap : k = {}, v = {}", k, v));
 317         return tribPortMap;
 318     }
 319
 320     private Map<String, List<Uint16>> chooseTribSlot(GraphPath<String,
 321         PceGraphEdge> path, Map<NodeId, PceNode> allPceNodes, int nbSlot) {
 322         LOG.info("In choosetribSlot: edgeList = {} ", path.getEdgeList());
 323         Map<String, List<Uint16>> tribSlotMap = new HashMap<>();
 324
 325         for (PceGraphEdge edge : path.getEdgeList()) {
 326             NodeId linkSrcNode = edge.link().getSourceId();
 327             String linkSrcTp = edge.link().getSourceTP().getValue();
 328             NodeId linkDestNode = edge.link().getDestId();
 329             String linkDestTp = edge.link().getDestTP().getValue();
 330             PceNode pceOtnNodeSrc = allPceNodes.get(linkSrcNode);
 331             PceNode pceOtnNodeDest = allPceNodes.get(linkDestNode);
 332             List<Uint16> srcTsPool = pceOtnNodeSrc.getAvailableTribSlots().get(linkSrcTp);
 333             List<Uint16> destTsPool = pceOtnNodeDest.getAvailableTribSlots().get(linkDestTp);
 334             List<Uint16> commonEdgeTsPoolList = new ArrayList<>();
 335             List<Uint16> tribSlotList = new ArrayList<>();
 336             for (Uint16 integer : srcTsPool) {
 337                 if (destTsPool.contains(integer)) {
 338                     commonEdgeTsPoolList.add(integer);
 339                 }
 340             }
 341             Collections.sort(commonEdgeTsPoolList);
 342             List<Uint16> commonGoodStartEdgeTsPoolList = new ArrayList<>();
 343             for (Uint16 startEdgeTsPool : commonEdgeTsPoolList) {
 344                 if (Integer.valueOf(1).equals(startEdgeTsPool.toJava() % nbSlot)
 345                         || nbSlot == 1) {
 346                     commonGoodStartEdgeTsPoolList.add(startEdgeTsPool);
 347                 }
 348             }
 349             Collections.sort(commonGoodStartEdgeTsPoolList);
 350             boolean goodTsList = false;
 351             for (Uint16 goodStartTsPool : commonGoodStartEdgeTsPoolList) {
 352                 int goodStartIndex = commonEdgeTsPoolList.indexOf(Uint16.valueOf(goodStartTsPool.intValue()));
 353                 if (!goodTsList && commonEdgeTsPoolList.size() - goodStartIndex >= nbSlot) {
 354                     for (int i = 0; i < nbSlot; i++) {
 355                         if (!commonEdgeTsPoolList.get(goodStartIndex + i)
 356                                 .equals(Uint16.valueOf(goodStartTsPool.toJava() + i))) {
 357                             goodTsList = false;
 358                             tribSlotList.clear();
 359                             break;
 360                         }
 361                         tribSlotList.add(commonEdgeTsPoolList.get(goodStartIndex + i));
 362                         goodTsList = true;
 363                     }
 364                 }
 365             }
 366             tribSlotMap.put(edge.link().getLinkId().getValue(), tribSlotList);
 367         }
 368         tribSlotMap.forEach((k,v) -> LOG.info("TribSlotMap : k = {}, v = {}", k, v));
 369         return tribSlotMap;
 370     }
 371
 372     private List<OpucnTribSlotDef> getMinMaxTpTs(Map<String, Uint16> tribPort, Map<String, List<Uint16>> tribSlot) {
 373         String tribport = tribPort.values().toArray()[0].toString();
 374         @SuppressWarnings("unchecked")
 375         List<Uint16> tsList = (List<Uint16>) tribSlot.values().toArray()[0];
 376         OpucnTribSlotDef minOpucnTs = OpucnTribSlotDef
 377             .getDefaultInstance(String.join(".", tribport, tsList.get(0).toString()));
 378         OpucnTribSlotDef maxOpucnTs = OpucnTribSlotDef
 379             .getDefaultInstance(String.join(".", tribport, tsList.get(tsList.size() - 1).toString()));
 380         List<OpucnTribSlotDef> minmaxTpTsList = new ArrayList<>();
 381         minmaxTpTsList.add(minOpucnTs);
 382         minmaxTpTsList.add(maxOpucnTs);
 383         return minmaxTpTsList;
 384     }
 385
 386     // Check the path OSNR
 387     private boolean checkOSNR(GraphPath<String, PceGraphEdge> path) {
 388         double linkOsnrDb;
 389         double osnrDb = 0;
 390         LOG.info("- In checkOSNR: OSNR of the transmitter = {} dB", TRX_OSNR);
 391         LOG.info("- In checkOSNR: add-path incremental OSNR = {} dB", ADD_OSNR);
 392         double inverseLocalOsnr = getInverseOsnrLinkLu(TRX_OSNR) + getInverseOsnrLinkLu(ADD_OSNR);
 393         for (PceGraphEdge edge : path.getEdgeList()) {
 394             if (edge.link().getlinkType() == OpenroadmLinkType.ROADMTOROADM) {
 395                 // link OSNR in dB
 396                 linkOsnrDb = edge.link().getosnr();
 397                 LOG.info("- In checkOSNR: OSNR of {} = {} dB", edge.link().getLinkId().getValue(), linkOsnrDb);
 398                 // 1 over the local OSNR, in linear units
 399                 inverseLocalOsnr += getInverseOsnrLinkLu(linkOsnrDb);
 400             }
 401         }
 402         try {
 403             osnrDb = getOsnrDb(1 / inverseLocalOsnr);
 404         } catch (ArithmeticException e) {
 405             LOG.debug("In checkOSNR: OSNR is equal to 0 and the number of links is: {}", path.getEdgeList().size());
 406             return false;
 407         }
 408         LOG.info("In checkOSNR: OSNR of the path is {} dB", osnrDb);
 409         return ((osnrDb + SYS_MARGIN) > MIN_OSNR_W100G);
 410     }
 411
 412     private double getOsnrDb(double osnrLu) {
 413         return (10 * Math.log10(osnrLu));
 414     }
 415
 416     private double getInverseOsnrLinkLu(double linkOsnrDb) {
 417         // 1 over the link OSNR, in linear units
 418         double linkOsnrLu = Math.pow(10, (linkOsnrDb / 10.0));
 419         LOG.debug("In retrieveosnr: the inverse of link osnr is {} (Linear Unit)", linkOsnrLu);
 420         return (CONST_OSNR / linkOsnrLu);
 421     }
 422
 423     /**
 424      * Get spectrum assignment for path.
 425      *
 426      * @param path                    the path for which we get spectrum assignment.
 427      * @param allPceNodes             all optical nodes.
 428      * @param spectralWidthSlotNumber number of slot for spectral width. Depends on
 429      *                                service type.
 430      * @return a spectrum assignment object which contains begin and end index. If
 431      *         no spectrum assignment found, beginIndex = stopIndex = 0
 432      */
 433     private SpectrumAssignment getSpectrumAssignment(GraphPath<String, PceGraphEdge> path,
 434             Map<NodeId, PceNode> allPceNodes, int spectralWidthSlotNumber) {
 435         byte[] freqMap = new byte[GridConstant.NB_OCTECTS];
 436         Arrays.fill(freqMap, (byte) GridConstant.AVAILABLE_SLOT_VALUE);
 437         BitSet result = BitSet.valueOf(freqMap);
 438         boolean isFlexGrid = true;
 439         LOG.info("Processing path {} with length {}", path, path.getLength());
 440         BitSet pceNodeFreqMap;
 441         for (PceGraphEdge edge : path.getEdgeList()) {
 442             LOG.info("Processing source {} ", edge.link().getSourceId());
 443             if (allPceNodes.containsKey(edge.link().getSourceId())) {
 444                 PceNode pceNode = allPceNodes.get(edge.link().getSourceId());
 445                 LOG.info("Processing PCE node {}", pceNode);
 446                 if (StringConstants.OPENROADM_DEVICE_VERSION_1_2_1.equals(pceNode.getVersion())) {
 447                     LOG.info("Node {}: version is {} and slot width granularity is {} -> fixed grid mode",
 448                         pceNode.getNodeId(), pceNode.getVersion(), pceNode.getSlotWidthGranularity());
 449                     isFlexGrid = false;
 450                 }
 451                 if ((pceNode.getSlotWidthGranularity().setScale(0, RoundingMode.CEILING)
 452                         .equals(GridConstant.SLOT_WIDTH_50))
 453                         && (pceNode.getCentralFreqGranularity().setScale(0, RoundingMode.CEILING)
 454                         .equals(GridConstant.SLOT_WIDTH_50))) {
 455                     LOG.info("Node {}: version is {} with slot width granularity  {} and central "
 456                             + "frequency granularity is {} -> fixed grid mode",
 457                         pceNode.getNodeId(), pceNode.getVersion(), pceNode.getSlotWidthGranularity(),
 458                         pceNode.getCentralFreqGranularity());
 459                     isFlexGrid = false;
 460                 }
 461                 pceNodeFreqMap = pceNode.getBitSetData();
 462                 LOG.debug("Pce node bitset {}", pceNodeFreqMap);
 463                 if (pceNodeFreqMap != null) {
 464                     result.and(pceNodeFreqMap);
 465                     LOG.debug("intermediate bitset {}", result);
 466                 }
 467             }
 468         }
 469         LOG.debug("Bitset result {}", result);
 470         return computeBestSpectrumAssignment(result, spectralWidthSlotNumber, isFlexGrid);
 471     }
 472
 473     /**
 474      * Compute spectrum assignment from spectrum occupation for spectral width.
 475      *
 476      * @param spectrumOccupation      the spectrum occupation BitSet.
 477      * @param spectralWidthSlotNumber the nb slots for spectral width.
 478      * @param isFlexGrid              true if flexible grid, false otherwise.
 479      * @return a spectrum assignment object which contains begin and stop index. If
 480      *         no spectrum assignment found, beginIndex = stopIndex = 0
 481      */
 482     private SpectrumAssignment computeBestSpectrumAssignment(BitSet spectrumOccupation, int spectralWidthSlotNumber,
 483             boolean isFlexGrid) {
 484         SpectrumAssignmentBuilder spectrumAssignmentBldr = new SpectrumAssignmentBuilder()
 485             .setBeginIndex(Uint16.valueOf(0))
 486             .setStopIndex(Uint16.valueOf(0))
 487             .setFlexGrid(isFlexGrid);
 488         BitSet referenceBitSet = new BitSet(spectralWidthSlotNumber);
 489         referenceBitSet.set(0, spectralWidthSlotNumber);
 490         int nbSteps = isFlexGrid ? spectralWidthSlotNumber : 1;
 491         //higher is the frequency, smallest is the wavelength number
 492         //in operational, the allocation is done through wavelength starting from the smallest
 493         //so we have to loop from the last element of the spectrum occupation
 494         for (int i = spectrumOccupation.size(); i >= spectralWidthSlotNumber; i -= nbSteps) {
 495             if (spectrumOccupation.get(i - spectralWidthSlotNumber, i).equals(referenceBitSet)) {
 496                 spectrumAssignmentBldr.setBeginIndex(Uint16.valueOf(i - spectralWidthSlotNumber));
 497                 spectrumAssignmentBldr.setStopIndex(Uint16.valueOf(i - 1));
 498                 break;
 499             }
 500         }
 501         return spectrumAssignmentBldr.build();
 502     }
 503 }