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.util.ArrayList;
  13 import java.util.Arrays;
  14 import java.util.BitSet;
  15 import java.util.Collections;
  16 import java.util.HashMap;
  17 import java.util.List;
  18 import java.util.Map;
  19 import org.jgrapht.GraphPath;
  20 import org.opendaylight.transportpce.common.ResponseCodes;
  21 import org.opendaylight.transportpce.common.StringConstants;
  22 import org.opendaylight.transportpce.common.fixedflex.GridConstant;
  23 import org.opendaylight.transportpce.common.fixedflex.GridUtils;
  24 import org.opendaylight.transportpce.pce.constraints.PceConstraints;
  25 import org.opendaylight.transportpce.pce.constraints.PceConstraints.ResourcePair;
  26 import org.opendaylight.transportpce.pce.networkanalyzer.PceNode;
  27 import org.opendaylight.transportpce.pce.networkanalyzer.PceResult;
  28 import org.opendaylight.yang.gen.v1.http.org.opendaylight.transportpce.pce.rev220118.SpectrumAssignment;
  29 import org.opendaylight.yang.gen.v1.http.org.opendaylight.transportpce.pce.rev220118.SpectrumAssignmentBuilder;
  30 import org.opendaylight.yang.gen.v1.http.org.openroadm.network.types.rev211210.OpenroadmLinkType;
  31 import org.opendaylight.yang.gen.v1.http.org.openroadm.otn.common.types.rev181130.OpucnTribSlotDef;
  32 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.network.rev180226.NodeId;
  33 import org.opendaylight.yangtools.yang.common.Uint16;
  34 import org.slf4j.Logger;
  35 import org.slf4j.LoggerFactory;
  36
  37 public class PostAlgoPathValidator {
  38     /* Logging. */
  39     private static final Logger LOG = LoggerFactory.getLogger(PostAlgoPathValidator.class);
  40
  41     private static final double MIN_OSNR_W100G = 17;
  42     private static final double TRX_OSNR = 33;
  43     private static final double ADD_OSNR = 30;
  44     public static final Long CONST_OSNR = 1L;
  45     public static final double SYS_MARGIN = 0;
  46
  47     @SuppressWarnings("fallthrough")
  48     @SuppressFBWarnings(
  49         value = "SF_SWITCH_FALLTHROUGH",
  50         justification = "intentional fallthrough")
  51     public PceResult checkPath(GraphPath<String, PceGraphEdge> path, Map<NodeId, PceNode> allPceNodes,
  52         PceResult pceResult, PceConstraints pceHardConstraints, String serviceType) {
  53
  54         // check if the path is empty
  55         if (path.getEdgeList().isEmpty()) {
  56             pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
  57             return pceResult;
  58         }
  59         int spectralWidthSlotNumber = GridConstant.SPECTRAL_WIDTH_SLOT_NUMBER_MAP
  60             .getOrDefault(serviceType, GridConstant.NB_SLOTS_100G);
  61         SpectrumAssignment spectrumAssignment = null;
  62         //variable to deal with 1GE (Nb=1) and 10GE (Nb=10) cases
  63         switch (serviceType) {
  64             case StringConstants.SERVICE_TYPE_OTUC2:
  65             case StringConstants.SERVICE_TYPE_OTUC3:
  66             case StringConstants.SERVICE_TYPE_OTUC4:
  67             case StringConstants.SERVICE_TYPE_400GE:
  68                 spectralWidthSlotNumber = GridConstant.SPECTRAL_WIDTH_SLOT_NUMBER_MAP
  69                     .getOrDefault(serviceType, GridConstant.NB_SLOTS_400G);
  70             //fallthrough
  71             case StringConstants.SERVICE_TYPE_100GE_T:
  72             case StringConstants.SERVICE_TYPE_OTU4:
  73                 spectrumAssignment = getSpectrumAssignment(path, allPceNodes, spectralWidthSlotNumber);
  74                 pceResult.setServiceType(serviceType);
  75                 if (spectrumAssignment.getBeginIndex().equals(Uint16.valueOf(0))
  76                         && spectrumAssignment.getStopIndex().equals(Uint16.valueOf(0))) {
  77                     pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
  78                     pceResult.setLocalCause(PceResult.LocalCause.NO_PATH_EXISTS);
  79                     return pceResult;
  80                 }
  81                 if (spectrumAssignment.getFlexGrid()) {
  82                     LOG.info("Spectrum assignment flexgrid mode");
  83                     pceResult.setResultWavelength(GridConstant.IRRELEVANT_WAVELENGTH_NUMBER);
  84                 } else {
  85                     LOG.info("Spectrum assignment fixedgrid mode");
  86                     pceResult.setResultWavelength(
  87                             GridUtils.getWaveLengthIndexFromSpectrumAssigment(spectrumAssignment.getBeginIndex()
  88                                 .toJava()));
  89                 }
  90                 pceResult.setMinFreq(GridUtils.getStartFrequencyFromIndex(spectrumAssignment.getBeginIndex().toJava()));
  91                 pceResult.setMaxFreq(GridUtils.getStopFrequencyFromIndex(spectrumAssignment.getStopIndex().toJava()));
  92                 LOG.info("In PostAlgoPathValidator: spectrum assignment found {} {}", spectrumAssignment, path);
  93
  94                 // Check the OSNR
  95                 if (!checkOSNR(path)) {
  96                     pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
  97                     pceResult.setLocalCause(PceResult.LocalCause.OUT_OF_SPEC_OSNR);
  98                     return pceResult;
  99                 }
 100
 101                 // Check if MaxLatency is defined in the hard constraints
 102                 if ((pceHardConstraints.getMaxLatency() != -1)
 103                         && (!checkLatency(pceHardConstraints.getMaxLatency(), path))) {
 104                     pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
 105                     pceResult.setLocalCause(PceResult.LocalCause.TOO_HIGH_LATENCY);
 106                     return pceResult;
 107                 }
 108
 109                 // Check if nodes are included in the hard constraints
 110                 if (!checkInclude(path, pceHardConstraints)) {
 111                     pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
 112                     pceResult.setLocalCause(PceResult.LocalCause.HD_NODE_INCLUDE);
 113                     return pceResult;
 114                 }
 115
 116                 // TODO here other post algo validations can be added
 117                 // more data can be sent to PceGraph module via PceResult structure if required
 118
 119                 pceResult.setRC(ResponseCodes.RESPONSE_OK);
 120                 pceResult.setLocalCause(PceResult.LocalCause.NONE);
 121                 break;
 122             case StringConstants.SERVICE_TYPE_100GE_M:
 123             case StringConstants.SERVICE_TYPE_10GE:
 124             case StringConstants.SERVICE_TYPE_1GE:
 125                 Map<String, Integer> tribSlotNbMap = Map.of(
 126                     StringConstants.SERVICE_TYPE_100GE_M, 20,
 127                     StringConstants.SERVICE_TYPE_10GE, 8,
 128                     StringConstants.SERVICE_TYPE_1GE, 1);
 129                 int tribSlotNb = tribSlotNbMap.get(serviceType);
 130                 pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
 131                 pceResult.setServiceType(serviceType);
 132                 Map<String, List<Uint16>> tribSlot = chooseTribSlot(path, allPceNodes, tribSlotNb);
 133                 Map<String, Uint16> tribPort = chooseTribPort(path, allPceNodes, tribSlot, tribSlotNb);
 134                 List<OpucnTribSlotDef> resultTribPortTribSlot = getMinMaxTpTs(tribPort, tribSlot);
 135
 136                 if (resultTribPortTribSlot.get(0) != null && resultTribPortTribSlot.get(1) != null) {
 137                     pceResult.setResultTribPortTribSlot(resultTribPortTribSlot);
 138                     pceResult.setRC(ResponseCodes.RESPONSE_OK);
 139                     LOG.info("In PostAlgoPathValidator: found TribPort {} - tribSlot {} - tribSlotNb {}",
 140                         tribPort, tribSlot, tribSlotNb);
 141                 }
 142                 break;
 143             case StringConstants.SERVICE_TYPE_ODU4:
 144             case StringConstants.SERVICE_TYPE_ODUC2:
 145             case StringConstants.SERVICE_TYPE_ODUC3:
 146             case StringConstants.SERVICE_TYPE_ODUC4:
 147             case StringConstants.SERVICE_TYPE_100GE_S:
 148                 pceResult.setRC(ResponseCodes.RESPONSE_OK);
 149                 pceResult.setServiceType(serviceType);
 150                 LOG.info("In PostAlgoPathValidator: ODU4/ODUCn path found {}", path);
 151                 break;
 152             default:
 153                 pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
 154                 LOG.warn("In PostAlgoPathValidator checkPath: unsupported serviceType {} found {}",
 155                     serviceType, path);
 156                 break;
 157         }
 158         return pceResult;
 159     }
 160
 161     // Check the latency
 162     private boolean checkLatency(Long maxLatency, GraphPath<String, PceGraphEdge> path) {
 163         double latency = 0;
 164
 165         for (PceGraphEdge edge : path.getEdgeList()) {
 166             if (edge.link() == null || edge.link().getLatency() == null) {
 167                 LOG.warn("- In checkLatency: the link {} does not contain latency field",
 168                     edge.link().getLinkId().getValue());
 169                 return false;
 170             }
 171             latency += edge.link().getLatency();
 172             LOG.debug("- In checkLatency: latency of {} = {} units", edge.link().getLinkId().getValue(), latency);
 173         }
 174         return (latency < maxLatency);
 175     }
 176
 177     // Check the inclusion if it is defined in the hard constraints
 178     private boolean checkInclude(GraphPath<String, PceGraphEdge> path, PceConstraints pceHardConstraintsInput) {
 179         List<ResourcePair> listToInclude = pceHardConstraintsInput.getListToInclude();
 180         if (listToInclude.isEmpty()) {
 181             return true;
 182         }
 183
 184         List<PceGraphEdge> pathEdges = path.getEdgeList();
 185         LOG.debug(" in checkInclude vertex list: [{}]", path.getVertexList());
 186
 187         List<String> listOfElementsSubNode = new ArrayList<>();
 188         listOfElementsSubNode.add(pathEdges.get(0).link().getsourceNetworkSupNodeId());
 189         listOfElementsSubNode.addAll(listOfElementsBuild(pathEdges, PceConstraints.ResourceType.NODE,
 190             pceHardConstraintsInput));
 191
 192         List<String> listOfElementsCLLI = new ArrayList<>();
 193         listOfElementsCLLI.add(pathEdges.get(0).link().getsourceCLLI());
 194         listOfElementsCLLI.addAll(listOfElementsBuild(pathEdges, PceConstraints.ResourceType.CLLI,
 195             pceHardConstraintsInput));
 196
 197         List<String> listOfElementsSRLG = new ArrayList<>();
 198         // first link is XPONDEROUTPUT, no SRLG for it
 199         listOfElementsSRLG.add("NONE");
 200         listOfElementsSRLG.addAll(listOfElementsBuild(pathEdges, PceConstraints.ResourceType.SRLG,
 201             pceHardConstraintsInput));
 202
 203         // validation: check each type for each element
 204         for (ResourcePair next : listToInclude) {
 205             int indx = -1;
 206             switch (next.getType()) {
 207                 case NODE:
 208                     if (listOfElementsSubNode.contains(next.getName())) {
 209                         indx = listOfElementsSubNode.indexOf(next.getName());
 210                     }
 211                     break;
 212                 case SRLG:
 213                     if (listOfElementsSRLG.contains(next.getName())) {
 214                         indx = listOfElementsSRLG.indexOf(next.getName());
 215                     }
 216                     break;
 217                 case CLLI:
 218                     if (listOfElementsCLLI.contains(next.getName())) {
 219                         indx = listOfElementsCLLI.indexOf(next.getName());
 220                     }
 221                     break;
 222                 default:
 223                     LOG.warn(" in checkInclude vertex list unsupported resource type: [{}]", next.getType());
 224             }
 225
 226             if (indx < 0) {
 227                 LOG.debug(" in checkInclude stopped : {} ", next.getName());
 228                 return false;
 229             }
 230
 231             LOG.debug(" in checkInclude next found {} in {}", next.getName(), path.getVertexList());
 232
 233             listOfElementsSubNode.subList(0, indx).clear();
 234             listOfElementsCLLI.subList(0, indx).clear();
 235             listOfElementsSRLG.subList(0, indx).clear();
 236         }
 237
 238         LOG.info(" in checkInclude passed : {} ", path.getVertexList());
 239         return true;
 240     }
 241
 242     private List<String> listOfElementsBuild(List<PceGraphEdge> pathEdges, PceConstraints.ResourceType type,
 243         PceConstraints pceHardConstraints) {
 244
 245         List<String> listOfElements = new ArrayList<>();
 246         for (PceGraphEdge link : pathEdges) {
 247             switch (type) {
 248                 case NODE:
 249                     listOfElements.add(link.link().getdestNetworkSupNodeId());
 250                     break;
 251                 case CLLI:
 252                     listOfElements.add(link.link().getdestCLLI());
 253                     break;
 254                 case SRLG:
 255                     if (link.link().getlinkType() != OpenroadmLinkType.ROADMTOROADM) {
 256                         listOfElements.add("NONE");
 257                         break;
 258                     }
 259                     // srlg of link is List<Long>. But in this algo we need string representation of
 260                     // one SRLG
 261                     // this should be any SRLG mentioned in include constraints if any of them if
 262                     // mentioned
 263                     boolean found = false;
 264                     for (Long srlg : link.link().getsrlgList()) {
 265                         String srlgStr = String.valueOf(srlg);
 266                         if (pceHardConstraints.getSRLGnames().contains(srlgStr)) {
 267                             listOfElements.add(srlgStr);
 268                             LOG.info("listOfElementsBuild. FOUND SRLG {} in link {}", srlgStr, link.link());
 269                             found = true;
 270                         }
 271                     }
 272                     if (!found) {
 273                         // there is no specific srlg to include. thus add to list just the first one
 274                         listOfElements.add("NONE");
 275                     }
 276                     break;
 277                 default:
 278                     LOG.debug("listOfElementsBuild unsupported resource type");
 279             }
 280         }
 281         return listOfElements;
 282     }
 283
 284     private Map<String, Uint16> chooseTribPort(GraphPath<String,
 285         PceGraphEdge> path, Map<NodeId, PceNode> allPceNodes, Map<String, List<Uint16>> tribSlotMap, int nbSlot) {
 286         LOG.info("In choosetribPort: edgeList = {} ", path.getEdgeList());
 287         Map<String, Uint16> tribPortMap = new HashMap<>();
 288
 289         for (PceGraphEdge edge : path.getEdgeList()) {
 290             NodeId linkSrcNode = edge.link().getSourceId();
 291             String linkSrcTp = edge.link().getSourceTP().getValue();
 292             NodeId linkDestNode = edge.link().getDestId();
 293             String linkDestTp = edge.link().getDestTP().getValue();
 294             PceNode pceOtnNodeSrc = allPceNodes.get(linkSrcNode);
 295             PceNode pceOtnNodeDest = allPceNodes.get(linkDestNode);
 296             List<Uint16> srcTpnPool = pceOtnNodeSrc.getAvailableTribPorts().get(linkSrcTp);
 297             List<Uint16> destTpnPool = pceOtnNodeDest.getAvailableTribPorts().get(linkDestTp);
 298             List<Uint16> commonEdgeTpnPool = new ArrayList<>();
 299             for (Uint16 srcTpn : srcTpnPool) {
 300                 if (destTpnPool.contains(srcTpn)) {
 301                     commonEdgeTpnPool.add(srcTpn);
 302                 }
 303             }
 304             Collections.sort(commonEdgeTpnPool);
 305             if (!commonEdgeTpnPool.isEmpty()) {
 306                 Integer startTribSlot = tribSlotMap.values().stream().findFirst().get().get(0).toJava();
 307                 Integer tribPort = (int) Math.ceil((double)startTribSlot / nbSlot);
 308                 for (Uint16 commonTribPort : commonEdgeTpnPool) {
 309                     if (tribPort.equals(commonTribPort.toJava())) {
 310                         tribPortMap.put(edge.link().getLinkId().getValue(), commonTribPort);
 311                     }
 312                 }
 313             }
 314         }
 315         tribPortMap.forEach((k,v) -> LOG.info("TribPortMap : k = {}, v = {}", k, v));
 316         return tribPortMap;
 317     }
 318
 319     private Map<String, List<Uint16>> chooseTribSlot(GraphPath<String,
 320         PceGraphEdge> path, Map<NodeId, PceNode> allPceNodes, int nbSlot) {
 321         LOG.info("In choosetribSlot: edgeList = {} ", path.getEdgeList());
 322         Map<String, List<Uint16>> tribSlotMap = new HashMap<>();
 323
 324         for (PceGraphEdge edge : path.getEdgeList()) {
 325             NodeId linkSrcNode = edge.link().getSourceId();
 326             String linkSrcTp = edge.link().getSourceTP().getValue();
 327             NodeId linkDestNode = edge.link().getDestId();
 328             String linkDestTp = edge.link().getDestTP().getValue();
 329             PceNode pceOtnNodeSrc = allPceNodes.get(linkSrcNode);
 330             PceNode pceOtnNodeDest = allPceNodes.get(linkDestNode);
 331             List<Uint16> srcTsPool = pceOtnNodeSrc.getAvailableTribSlots().get(linkSrcTp);
 332             List<Uint16> destTsPool = pceOtnNodeDest.getAvailableTribSlots().get(linkDestTp);
 333             List<Uint16> commonEdgeTsPoolList = new ArrayList<>();
 334             List<Uint16> tribSlotList = new ArrayList<>();
 335             for (Uint16 integer : srcTsPool) {
 336                 if (destTsPool.contains(integer)) {
 337                     commonEdgeTsPoolList.add(integer);
 338                 }
 339             }
 340             Collections.sort(commonEdgeTsPoolList);
 341             List<Uint16> commonGoodStartEdgeTsPoolList = new ArrayList<>();
 342             for (Uint16 startEdgeTsPool : commonEdgeTsPoolList) {
 343                 if (Integer.valueOf(1).equals(startEdgeTsPool.toJava() % nbSlot)
 344                         || nbSlot == 1) {
 345                     commonGoodStartEdgeTsPoolList.add(startEdgeTsPool);
 346                 }
 347             }
 348             Collections.sort(commonGoodStartEdgeTsPoolList);
 349             boolean goodTsList = false;
 350             for (Uint16 goodStartTsPool : commonGoodStartEdgeTsPoolList) {
 351                 int goodStartIndex = commonEdgeTsPoolList.indexOf(Uint16.valueOf(goodStartTsPool.intValue()));
 352                 if (!goodTsList && commonEdgeTsPoolList.size() - goodStartIndex >= nbSlot) {
 353                     for (int i = 0; i < nbSlot; i++) {
 354                         if (!commonEdgeTsPoolList.get(goodStartIndex + i)
 355                                 .equals(Uint16.valueOf(goodStartTsPool.toJava() + i))) {
 356                             goodTsList = false;
 357                             tribSlotList.clear();
 358                             break;
 359                         }
 360                         tribSlotList.add(commonEdgeTsPoolList.get(goodStartIndex + i));
 361                         goodTsList = true;
 362                     }
 363                 }
 364             }
 365             tribSlotMap.put(edge.link().getLinkId().getValue(), tribSlotList);
 366         }
 367         tribSlotMap.forEach((k,v) -> LOG.info("TribSlotMap : k = {}, v = {}", k, v));
 368         return tribSlotMap;
 369     }
 370
 371     private List<OpucnTribSlotDef> getMinMaxTpTs(Map<String, Uint16> tribPort, Map<String, List<Uint16>> tribSlot) {
 372         String tribport = tribPort.values().toArray()[0].toString();
 373         @SuppressWarnings("unchecked")
 374         List<Uint16> tsList = (List<Uint16>) tribSlot.values().toArray()[0];
 375         OpucnTribSlotDef minOpucnTs = OpucnTribSlotDef
 376             .getDefaultInstance(String.join(".", tribport, tsList.get(0).toString()));
 377         OpucnTribSlotDef maxOpucnTs = OpucnTribSlotDef
 378             .getDefaultInstance(String.join(".", tribport, tsList.get(tsList.size() - 1).toString()));
 379         List<OpucnTribSlotDef> minmaxTpTsList = new ArrayList<>();
 380         minmaxTpTsList.add(minOpucnTs);
 381         minmaxTpTsList.add(maxOpucnTs);
 382         return minmaxTpTsList;
 383     }
 384
 385     // Check the path OSNR
 386     private boolean checkOSNR(GraphPath<String, PceGraphEdge> path) {
 387         double linkOsnrDb;
 388         double osnrDb = 0;
 389         LOG.info("- In checkOSNR: OSNR of the transmitter = {} dB", TRX_OSNR);
 390         LOG.info("- In checkOSNR: add-path incremental OSNR = {} dB", ADD_OSNR);
 391         double inverseLocalOsnr = getInverseOsnrLinkLu(TRX_OSNR) + getInverseOsnrLinkLu(ADD_OSNR);
 392         for (PceGraphEdge edge : path.getEdgeList()) {
 393             if (edge.link().getlinkType() == OpenroadmLinkType.ROADMTOROADM) {
 394                 // link OSNR in dB
 395                 linkOsnrDb = edge.link().getosnr();
 396                 LOG.info("- In checkOSNR: OSNR of {} = {} dB", edge.link().getLinkId().getValue(), linkOsnrDb);
 397                 // 1 over the local OSNR, in linear units
 398                 inverseLocalOsnr += getInverseOsnrLinkLu(linkOsnrDb);
 399             }
 400         }
 401         try {
 402             osnrDb = getOsnrDb(1 / inverseLocalOsnr);
 403         } catch (ArithmeticException e) {
 404             LOG.debug("In checkOSNR: OSNR is equal to 0 and the number of links is: {}", path.getEdgeList().size());
 405             return false;
 406         }
 407         LOG.info("In checkOSNR: OSNR of the path is {} dB", osnrDb);
 408         return ((osnrDb + SYS_MARGIN) > MIN_OSNR_W100G);
 409     }
 410
 411     private double getOsnrDb(double osnrLu) {
 412         return (10 * Math.log10(osnrLu));
 413     }
 414
 415     private double getInverseOsnrLinkLu(double linkOsnrDb) {
 416         // 1 over the link OSNR, in linear units
 417         double linkOsnrLu = Math.pow(10, (linkOsnrDb / 10.0));
 418         LOG.debug("In retrieveosnr: the inverse of link osnr is {} (Linear Unit)", linkOsnrLu);
 419         return (CONST_OSNR / linkOsnrLu);
 420     }
 421
 422     /**
 423      * Get spectrum assignment for path.
 424      *
 425      * @param path                    the path for which we get spectrum assignment.
 426      * @param allPceNodes             all optical nodes.
 427      * @param spectralWidthSlotNumber number of slot for spectral width. Depends on
 428      *                                service type.
 429      * @return a spectrum assignment object which contains begin and end index. If
 430      *         no spectrum assignment found, beginIndex = stopIndex = 0
 431      */
 432     private SpectrumAssignment getSpectrumAssignment(GraphPath<String, PceGraphEdge> path,
 433             Map<NodeId, PceNode> allPceNodes, int spectralWidthSlotNumber) {
 434         byte[] freqMap = new byte[GridConstant.NB_OCTECTS];
 435         Arrays.fill(freqMap, (byte) GridConstant.AVAILABLE_SLOT_VALUE);
 436         BitSet result = BitSet.valueOf(freqMap);
 437         boolean isFlexGrid = true;
 438         LOG.info("Processing path {} with length {}", path, path.getLength());
 439         BitSet pceNodeFreqMap;
 440         for (PceGraphEdge edge : path.getEdgeList()) {
 441             LOG.info("Processing source {} ", edge.link().getSourceId());
 442             if (allPceNodes.containsKey(edge.link().getSourceId())) {
 443                 PceNode pceNode = allPceNodes.get(edge.link().getSourceId());
 444                 LOG.info("Processing PCE node {}", pceNode);
 445                 if (StringConstants.OPENROADM_DEVICE_VERSION_1_2_1.equals(pceNode.getVersion())) {
 446                     LOG.info("Node {}: version is {} and slot width granularity is {} -> fixed grid mode",
 447                         pceNode.getNodeId(), pceNode.getVersion(), pceNode.getSlotWidthGranularity());
 448                     isFlexGrid = false;
 449                 }
 450                 if ((pceNode.getSlotWidthGranularity().equals(GridConstant.SLOT_WIDTH_50))
 451                     && (pceNode.getCentralFreqGranularity().equals(GridConstant.SLOT_WIDTH_50))) {
 452                     LOG.info("Node {}: version is {} with slot width granularity  {} and central "
 453                             + "frequency granularity is {} -> fixed grid mode",
 454                         pceNode.getNodeId(), pceNode.getVersion(), pceNode.getSlotWidthGranularity(),
 455                         pceNode.getCentralFreqGranularity());
 456                     isFlexGrid = false;
 457                 }
 458                 pceNodeFreqMap = pceNode.getBitSetData();
 459                 LOG.debug("Pce node bitset {}", pceNodeFreqMap);
 460                 if (pceNodeFreqMap != null) {
 461                     result.and(pceNodeFreqMap);
 462                     LOG.debug("intermediate bitset {}", result);
 463                 }
 464             }
 465         }
 466         LOG.debug("Bitset result {}", result);
 467         return computeBestSpectrumAssignment(result, spectralWidthSlotNumber, isFlexGrid);
 468     }
 469
 470     /**
 471      * Compute spectrum assignment from spectrum occupation for spectral width.
 472      *
 473      * @param spectrumOccupation      the spectrum occupation BitSet.
 474      * @param spectralWidthSlotNumber the nb slots for spectral width.
 475      * @param isFlexGrid              true if flexible grid, false otherwise.
 476      * @return a spectrum assignment object which contains begin and stop index. If
 477      *         no spectrum assignment found, beginIndex = stopIndex = 0
 478      */
 479     private SpectrumAssignment computeBestSpectrumAssignment(BitSet spectrumOccupation, int spectralWidthSlotNumber,
 480             boolean isFlexGrid) {
 481         SpectrumAssignmentBuilder spectrumAssignmentBldr = new SpectrumAssignmentBuilder()
 482             .setBeginIndex(Uint16.valueOf(0))
 483             .setStopIndex(Uint16.valueOf(0))
 484             .setFlexGrid(isFlexGrid);
 485         BitSet referenceBitSet = new BitSet(spectralWidthSlotNumber);
 486         referenceBitSet.set(0, spectralWidthSlotNumber);
 487         int nbSteps = isFlexGrid ? spectralWidthSlotNumber : 1;
 488         //higher is the frequency, smallest is the wavelength number
 489         //in operational, the allocation is done through wavelength starting from the smallest
 490         //so we have to loop from the last element of the spectrum occupation
 491         for (int i = spectrumOccupation.size(); i >= spectralWidthSlotNumber; i -= nbSteps) {
 492             if (spectrumOccupation.get(i - spectralWidthSlotNumber, i).equals(referenceBitSet)) {
 493                 spectrumAssignmentBldr.setBeginIndex(Uint16.valueOf(i - spectralWidthSlotNumber));
 494                 spectrumAssignmentBldr.setStopIndex(Uint16.valueOf(i - 1));
 495                 break;
 496             }
 497         }
 498         return spectrumAssignmentBldr.build();
 499     }
 500 }