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.rev210701.SpectrumAssignment;
  29 import org.opendaylight.yang.gen.v1.http.org.opendaylight.transportpce.pce.rev210701.SpectrumAssignmentBuilder;
  30 import org.opendaylight.yang.gen.v1.http.org.openroadm.network.types.rev200529.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_OTUC4:
  65             case StringConstants.SERVICE_TYPE_400GE:
  66                 spectralWidthSlotNumber = GridConstant.SPECTRAL_WIDTH_SLOT_NUMBER_MAP
  67                     .getOrDefault(serviceType, GridConstant.NB_SLOTS_400G);
  68             //fallthrough
  69             case StringConstants.SERVICE_TYPE_100GE_T:
  70             case StringConstants.SERVICE_TYPE_OTU4:
  71                 spectrumAssignment = getSpectrumAssignment(path, allPceNodes, spectralWidthSlotNumber);
  72                 pceResult.setServiceType(serviceType);
  73                 if (spectrumAssignment.getBeginIndex().equals(Uint16.valueOf(0))
  74                         && spectrumAssignment.getStopIndex().equals(Uint16.valueOf(0))) {
  75                     pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
  76                     pceResult.setLocalCause(PceResult.LocalCause.NO_PATH_EXISTS);
  77                     return pceResult;
  78                 }
  79                 if (spectrumAssignment.getFlexGrid()) {
  80                     LOG.info("Spectrum assignment flexgrid mode");
  81                     pceResult.setResultWavelength(GridConstant.IRRELEVANT_WAVELENGTH_NUMBER);
  82                 } else {
  83                     LOG.info("Spectrum assignment fixedgrid mode");
  84                     pceResult.setResultWavelength(
  85                             GridUtils.getWaveLengthIndexFromSpectrumAssigment(spectrumAssignment.getBeginIndex()
  86                                 .toJava()));
  87                 }
  88                 pceResult.setMinFreq(GridUtils.getStartFrequencyFromIndex(spectrumAssignment.getBeginIndex().toJava()));
  89                 pceResult.setMaxFreq(GridUtils.getStopFrequencyFromIndex(spectrumAssignment.getStopIndex().toJava()));
  90                 LOG.info("In PostAlgoPathValidator: spectrum assignment found {} {}", spectrumAssignment, path);
  91
  92                 // Check the OSNR
  93                 if (!checkOSNR(path)) {
  94                     pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
  95                     pceResult.setLocalCause(PceResult.LocalCause.OUT_OF_SPEC_OSNR);
  96                     return pceResult;
  97                 }
  98
  99                 // Check if MaxLatency is defined in the hard constraints
 100                 if ((pceHardConstraints.getMaxLatency() != -1)
 101                         && (!checkLatency(pceHardConstraints.getMaxLatency(), path))) {
 102                     pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
 103                     pceResult.setLocalCause(PceResult.LocalCause.TOO_HIGH_LATENCY);
 104                     return pceResult;
 105                 }
 106
 107                 // Check if nodes are included in the hard constraints
 108                 if (!checkInclude(path, pceHardConstraints)) {
 109                     pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
 110                     pceResult.setLocalCause(PceResult.LocalCause.HD_NODE_INCLUDE);
 111                     return pceResult;
 112                 }
 113
 114                 // TODO here other post algo validations can be added
 115                 // more data can be sent to PceGraph module via PceResult structure if required
 116
 117                 pceResult.setRC(ResponseCodes.RESPONSE_OK);
 118                 pceResult.setLocalCause(PceResult.LocalCause.NONE);
 119                 break;
 120             case StringConstants.SERVICE_TYPE_100GE_M:
 121             case StringConstants.SERVICE_TYPE_10GE:
 122             case StringConstants.SERVICE_TYPE_1GE:
 123                 Map<String, Integer> tribSlotNbMap = Map.of(
 124                     StringConstants.SERVICE_TYPE_100GE_M, 20,
 125                     StringConstants.SERVICE_TYPE_10GE, 8,
 126                     StringConstants.SERVICE_TYPE_1GE, 1);
 127                 int tribSlotNb = tribSlotNbMap.get(serviceType);
 128                 pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
 129                 pceResult.setServiceType(serviceType);
 130                 Map<String, List<Uint16>> tribSlot = chooseTribSlot(path, allPceNodes, tribSlotNb);
 131                 Map<String, Uint16> tribPort = chooseTribPort(path, allPceNodes, tribSlot, tribSlotNb);
 132                 List<OpucnTribSlotDef> resultTribPortTribSlot = getMinMaxTpTs(tribPort, tribSlot);
 133
 134                 if (resultTribPortTribSlot.get(0) != null && resultTribPortTribSlot.get(1) != null) {
 135                     pceResult.setResultTribPortTribSlot(resultTribPortTribSlot);
 136                     pceResult.setRC(ResponseCodes.RESPONSE_OK);
 137                     LOG.info("In PostAlgoPathValidator: found TribPort {} - tribSlot {} - tribSlotNb {}",
 138                         tribPort, tribSlot, tribSlotNb);
 139                 }
 140                 break;
 141             case StringConstants.SERVICE_TYPE_ODU4:
 142             case StringConstants.SERVICE_TYPE_ODUC4:
 143             case StringConstants.SERVICE_TYPE_100GE_S:
 144                 pceResult.setRC(ResponseCodes.RESPONSE_OK);
 145                 LOG.info("In PostAlgoPathValidator: ODU4/ODUC4 path found {}", path);
 146                 break;
 147             default:
 148                 pceResult.setRC(ResponseCodes.RESPONSE_FAILED);
 149                 LOG.warn("In PostAlgoPathValidator checkPath: unsupported serviceType {} found {}",
 150                     serviceType, path);
 151                 break;
 152         }
 153         return pceResult;
 154     }
 155
 156     // Check the latency
 157     private boolean checkLatency(Long maxLatency, GraphPath<String, PceGraphEdge> path) {
 158         double latency = 0;
 159
 160         for (PceGraphEdge edge : path.getEdgeList()) {
 161             try {
 162                 latency += edge.link().getLatency();
 163                 LOG.debug("- In checkLatency: latency of {} = {} units", edge.link().getLinkId().getValue(), latency);
 164             } catch (NullPointerException e) {
 165                 LOG.warn("- In checkLatency: the link {} does not contain latency field",
 166                     edge.link().getLinkId().getValue());
 167             }
 168         }
 169         return (latency < maxLatency);
 170     }
 171
 172     // Check the inclusion if it is defined in the hard constraints
 173     private boolean checkInclude(GraphPath<String, PceGraphEdge> path, PceConstraints pceHardConstraintsInput) {
 174         List<ResourcePair> listToInclude = pceHardConstraintsInput.getListToInclude();
 175         if (listToInclude.isEmpty()) {
 176             return true;
 177         }
 178
 179         List<PceGraphEdge> pathEdges = path.getEdgeList();
 180         LOG.debug(" in checkInclude vertex list: [{}]", path.getVertexList());
 181
 182         List<String> listOfElementsSubNode = new ArrayList<>();
 183         listOfElementsSubNode.add(pathEdges.get(0).link().getsourceNetworkSupNodeId());
 184         listOfElementsSubNode.addAll(listOfElementsBuild(pathEdges, PceConstraints.ResourceType.NODE,
 185             pceHardConstraintsInput));
 186
 187         List<String> listOfElementsCLLI = new ArrayList<>();
 188         listOfElementsCLLI.add(pathEdges.get(0).link().getsourceCLLI());
 189         listOfElementsCLLI.addAll(listOfElementsBuild(pathEdges, PceConstraints.ResourceType.CLLI,
 190             pceHardConstraintsInput));
 191
 192         List<String> listOfElementsSRLG = new ArrayList<>();
 193         // first link is XPONDEROUTPUT, no SRLG for it
 194         listOfElementsSRLG.add("NONE");
 195         listOfElementsSRLG.addAll(listOfElementsBuild(pathEdges, PceConstraints.ResourceType.SRLG,
 196             pceHardConstraintsInput));
 197
 198         // validation: check each type for each element
 199         for (ResourcePair next : listToInclude) {
 200             int indx = -1;
 201             switch (next.getType()) {
 202                 case NODE:
 203                     if (listOfElementsSubNode.contains(next.getName())) {
 204                         indx = listOfElementsSubNode.indexOf(next.getName());
 205                     }
 206                     break;
 207                 case SRLG:
 208                     if (listOfElementsSRLG.contains(next.getName())) {
 209                         indx = listOfElementsSRLG.indexOf(next.getName());
 210                     }
 211                     break;
 212                 case CLLI:
 213                     if (listOfElementsCLLI.contains(next.getName())) {
 214                         indx = listOfElementsCLLI.indexOf(next.getName());
 215                     }
 216                     break;
 217                 default:
 218                     LOG.warn(" in checkInclude vertex list unsupported resource type: [{}]", next.getType());
 219             }
 220
 221             if (indx < 0) {
 222                 LOG.debug(" in checkInclude stopped : {} ", next.getName());
 223                 return false;
 224             }
 225
 226             LOG.debug(" in checkInclude next found {} in {}", next.getName(), path.getVertexList());
 227
 228             listOfElementsSubNode.subList(0, indx).clear();
 229             listOfElementsCLLI.subList(0, indx).clear();
 230             listOfElementsSRLG.subList(0, indx).clear();
 231         }
 232
 233         LOG.info(" in checkInclude passed : {} ", path.getVertexList());
 234         return true;
 235     }
 236
 237     private List<String> listOfElementsBuild(List<PceGraphEdge> pathEdges, PceConstraints.ResourceType type,
 238         PceConstraints pceHardConstraints) {
 239
 240         List<String> listOfElements = new ArrayList<>();
 241         for (PceGraphEdge link : pathEdges) {
 242             switch (type) {
 243                 case NODE:
 244                     listOfElements.add(link.link().getdestNetworkSupNodeId());
 245                     break;
 246                 case CLLI:
 247                     listOfElements.add(link.link().getdestCLLI());
 248                     break;
 249                 case SRLG:
 250                     if (link.link().getlinkType() != OpenroadmLinkType.ROADMTOROADM) {
 251                         listOfElements.add("NONE");
 252                         break;
 253                     }
 254                     // srlg of link is List<Long>. But in this algo we need string representation of
 255                     // one SRLG
 256                     // this should be any SRLG mentioned in include constraints if any of them if
 257                     // mentioned
 258                     boolean found = false;
 259                     for (Long srlg : link.link().getsrlgList()) {
 260                         String srlgStr = String.valueOf(srlg);
 261                         if (pceHardConstraints.getSRLGnames().contains(srlgStr)) {
 262                             listOfElements.add(srlgStr);
 263                             LOG.info("listOfElementsBuild. FOUND SRLG {} in link {}", srlgStr, link.link());
 264                             found = true;
 265                         }
 266                     }
 267                     if (!found) {
 268                         // there is no specific srlg to include. thus add to list just the first one
 269                         listOfElements.add("NONE");
 270                     }
 271                     break;
 272                 default:
 273                     LOG.debug("listOfElementsBuild unsupported resource type");
 274             }
 275         }
 276         return listOfElements;
 277     }
 278
 279     private Map<String, Uint16> chooseTribPort(GraphPath<String,
 280         PceGraphEdge> path, Map<NodeId, PceNode> allPceNodes, Map<String, List<Uint16>> tribSlotMap, int nbSlot) {
 281         LOG.info("In choosetribPort: edgeList = {} ", path.getEdgeList());
 282         Map<String, Uint16> tribPortMap = new HashMap<>();
 283
 284         for (PceGraphEdge edge : path.getEdgeList()) {
 285             NodeId linkSrcNode = edge.link().getSourceId();
 286             String linkSrcTp = edge.link().getSourceTP().getValue();
 287             NodeId linkDestNode = edge.link().getDestId();
 288             String linkDestTp = edge.link().getDestTP().getValue();
 289             PceNode pceOtnNodeSrc = allPceNodes.get(linkSrcNode);
 290             PceNode pceOtnNodeDest = allPceNodes.get(linkDestNode);
 291             List<Uint16> srcTpnPool = pceOtnNodeSrc.getAvailableTribPorts().get(linkSrcTp);
 292             List<Uint16> destTpnPool = pceOtnNodeDest.getAvailableTribPorts().get(linkDestTp);
 293             List<Uint16> commonEdgeTpnPool = new ArrayList<>();
 294             for (Uint16 srcTpn : srcTpnPool) {
 295                 if (destTpnPool.contains(srcTpn)) {
 296                     commonEdgeTpnPool.add(srcTpn);
 297                 }
 298             }
 299             Collections.sort(commonEdgeTpnPool);
 300             if (!commonEdgeTpnPool.isEmpty()) {
 301                 Integer startTribSlot = tribSlotMap.values().stream().findFirst().get().get(0).toJava();
 302                 Integer tribPort = (int) Math.ceil((double)startTribSlot / nbSlot);
 303                 for (Uint16 commonTribPort : commonEdgeTpnPool) {
 304                     if (tribPort.equals(commonTribPort.toJava())) {
 305                         tribPortMap.put(edge.link().getLinkId().getValue(), commonTribPort);
 306                     }
 307                 }
 308             }
 309         }
 310         tribPortMap.forEach((k,v) -> LOG.info("TribPortMap : k = {}, v = {}", k, v));
 311         return tribPortMap;
 312     }
 313
 314     private Map<String, List<Uint16>> chooseTribSlot(GraphPath<String,
 315         PceGraphEdge> path, Map<NodeId, PceNode> allPceNodes, int nbSlot) {
 316         LOG.info("In choosetribSlot: edgeList = {} ", path.getEdgeList());
 317         Map<String, List<Uint16>> tribSlotMap = new HashMap<>();
 318
 319         for (PceGraphEdge edge : path.getEdgeList()) {
 320             NodeId linkSrcNode = edge.link().getSourceId();
 321             String linkSrcTp = edge.link().getSourceTP().getValue();
 322             NodeId linkDestNode = edge.link().getDestId();
 323             String linkDestTp = edge.link().getDestTP().getValue();
 324             PceNode pceOtnNodeSrc = allPceNodes.get(linkSrcNode);
 325             PceNode pceOtnNodeDest = allPceNodes.get(linkDestNode);
 326             List<Uint16> srcTsPool = pceOtnNodeSrc.getAvailableTribSlots().get(linkSrcTp);
 327             List<Uint16> destTsPool = pceOtnNodeDest.getAvailableTribSlots().get(linkDestTp);
 328             List<Uint16> commonEdgeTsPoolList = new ArrayList<>();
 329             List<Uint16> tribSlotList = new ArrayList<>();
 330             for (Uint16 integer : srcTsPool) {
 331                 if (destTsPool.contains(integer)) {
 332                     commonEdgeTsPoolList.add(integer);
 333                 }
 334             }
 335             Collections.sort(commonEdgeTsPoolList);
 336             List<Uint16> commonGoodStartEdgeTsPoolList = new ArrayList<>();
 337             for (Uint16 startEdgeTsPool : commonEdgeTsPoolList) {
 338                 if (Integer.valueOf(1).equals(startEdgeTsPool.toJava() % nbSlot)
 339                         || nbSlot == 1) {
 340                     commonGoodStartEdgeTsPoolList.add(startEdgeTsPool);
 341                 }
 342             }
 343             Collections.sort(commonGoodStartEdgeTsPoolList);
 344             boolean goodTsList = false;
 345             for (Uint16 goodStartTsPool : commonGoodStartEdgeTsPoolList) {
 346                 int goodStartIndex = commonEdgeTsPoolList.indexOf(Uint16.valueOf(goodStartTsPool.intValue()));
 347                 if (!goodTsList && commonEdgeTsPoolList.size() - goodStartIndex >= nbSlot) {
 348                     for (int i = 0; i < nbSlot; i++) {
 349                         if (!commonEdgeTsPoolList.get(goodStartIndex + i)
 350                                 .equals(Uint16.valueOf(goodStartTsPool.toJava() + i))) {
 351                             goodTsList = false;
 352                             tribSlotList.clear();
 353                             break;
 354                         }
 355                         tribSlotList.add(commonEdgeTsPoolList.get(goodStartIndex + i));
 356                         goodTsList = true;
 357                     }
 358                 }
 359             }
 360             tribSlotMap.put(edge.link().getLinkId().getValue(), tribSlotList);
 361         }
 362         tribSlotMap.forEach((k,v) -> LOG.info("TribSlotMap : k = {}, v = {}", k, v));
 363         return tribSlotMap;
 364     }
 365
 366     private List<OpucnTribSlotDef> getMinMaxTpTs(Map<String, Uint16> tribPort, Map<String, List<Uint16>> tribSlot) {
 367         String tribport = tribPort.values().toArray()[0].toString();
 368         @SuppressWarnings("unchecked")
 369         List<Uint16> tsList = (List<Uint16>) tribSlot.values().toArray()[0];
 370         OpucnTribSlotDef minOpucnTs = OpucnTribSlotDef
 371             .getDefaultInstance(String.join(".", tribport, tsList.get(0).toString()));
 372         OpucnTribSlotDef maxOpucnTs = OpucnTribSlotDef
 373             .getDefaultInstance(String.join(".", tribport, tsList.get(tsList.size() - 1).toString()));
 374         List<OpucnTribSlotDef> minmaxTpTsList = new ArrayList<>();
 375         minmaxTpTsList.add(minOpucnTs);
 376         minmaxTpTsList.add(maxOpucnTs);
 377         return minmaxTpTsList;
 378     }
 379
 380     // Check the path OSNR
 381     private boolean checkOSNR(GraphPath<String, PceGraphEdge> path) {
 382         double linkOsnrDb;
 383         double osnrDb = 0;
 384         LOG.info("- In checkOSNR: OSNR of the transmitter = {} dB", TRX_OSNR);
 385         LOG.info("- In checkOSNR: add-path incremental OSNR = {} dB", ADD_OSNR);
 386         double inverseLocalOsnr = getInverseOsnrLinkLu(TRX_OSNR) + getInverseOsnrLinkLu(ADD_OSNR);
 387         for (PceGraphEdge edge : path.getEdgeList()) {
 388             if (edge.link().getlinkType() == OpenroadmLinkType.ROADMTOROADM) {
 389                 // link OSNR in dB
 390                 linkOsnrDb = edge.link().getosnr();
 391                 LOG.info("- In checkOSNR: OSNR of {} = {} dB", edge.link().getLinkId().getValue(), linkOsnrDb);
 392                 // 1 over the local OSNR, in linear units
 393                 inverseLocalOsnr += getInverseOsnrLinkLu(linkOsnrDb);
 394             }
 395         }
 396         try {
 397             osnrDb = getOsnrDb(1 / inverseLocalOsnr);
 398         } catch (ArithmeticException e) {
 399             LOG.debug("In checkOSNR: OSNR is equal to 0 and the number of links is: {}", path.getEdgeList().size());
 400             return false;
 401         }
 402         LOG.info("In checkOSNR: OSNR of the path is {} dB", osnrDb);
 403         return ((osnrDb + SYS_MARGIN) > MIN_OSNR_W100G);
 404     }
 405
 406     private double getOsnrDb(double osnrLu) {
 407         return (10 * Math.log10(osnrLu));
 408     }
 409
 410     private double getInverseOsnrLinkLu(double linkOsnrDb) {
 411         // 1 over the link OSNR, in linear units
 412         double linkOsnrLu = Math.pow(10, (linkOsnrDb / 10.0));
 413         LOG.debug("In retrieveosnr: the inverse of link osnr is {} (Linear Unit)", linkOsnrLu);
 414         return (CONST_OSNR / linkOsnrLu);
 415     }
 416
 417     /**
 418      * Get spectrum assignment for path.
 419      *
 420      * @param path                    the path for which we get spectrum assignment.
 421      * @param allPceNodes             all optical nodes.
 422      * @param spectralWidthSlotNumber number of slot for spectral width. Depends on
 423      *                                service type.
 424      * @return a spectrum assignment object which contains begin and end index. If
 425      *         no spectrum assignment found, beginIndex = stopIndex = 0
 426      */
 427     private SpectrumAssignment getSpectrumAssignment(GraphPath<String, PceGraphEdge> path,
 428             Map<NodeId, PceNode> allPceNodes, int spectralWidthSlotNumber) {
 429         byte[] freqMap = new byte[GridConstant.NB_OCTECTS];
 430         Arrays.fill(freqMap, (byte) GridConstant.AVAILABLE_SLOT_VALUE);
 431         BitSet result = BitSet.valueOf(freqMap);
 432         boolean isFlexGrid = true;
 433         LOG.info("Processing path {} with length {}", path, path.getLength());
 434         BitSet pceNodeFreqMap;
 435         for (PceGraphEdge edge : path.getEdgeList()) {
 436             LOG.info("Processing source {} ", edge.link().getSourceId());
 437             if (allPceNodes.containsKey(edge.link().getSourceId())) {
 438                 PceNode pceNode = allPceNodes.get(edge.link().getSourceId());
 439                 LOG.info("Processing PCE node {}", pceNode);
 440                 if (StringConstants.OPENROADM_DEVICE_VERSION_1_2_1.equals(pceNode.getVersion())) {
 441                     LOG.info("Node {}: version is {} and slot width granularity is {} -> fixed grid mode",
 442                         pceNode.getNodeId(), pceNode.getVersion(), pceNode.getSlotWidthGranularity());
 443                     isFlexGrid = false;
 444                 }
 445                 if ((pceNode.getSlotWidthGranularity().equals(GridConstant.SLOT_WIDTH_50))
 446                     && (pceNode.getCentralFreqGranularity().equals(GridConstant.SLOT_WIDTH_50))) {
 447                     LOG.info("Node {}: version is {} with slot width granularity  {} and central "
 448                             + "frequency granularity is {} -> fixed grid mode",
 449                         pceNode.getNodeId(), pceNode.getVersion(), pceNode.getSlotWidthGranularity(),
 450                         pceNode.getCentralFreqGranularity());
 451                     isFlexGrid = false;
 452                 }
 453                 pceNodeFreqMap = pceNode.getBitSetData();
 454                 LOG.debug("Pce node bitset {}", pceNodeFreqMap);
 455                 if (pceNodeFreqMap != null) {
 456                     result.and(pceNodeFreqMap);
 457                     LOG.debug("intermediate bitset {}", result);
 458                 }
 459             }
 460         }
 461         LOG.debug("Bitset result {}", result);
 462         return computeBestSpectrumAssignment(result, spectralWidthSlotNumber, isFlexGrid);
 463     }
 464
 465     /**
 466      * Compute spectrum assignment from spectrum occupation for spectral width.
 467      *
 468      * @param spectrumOccupation      the spectrum occupation BitSet.
 469      * @param spectralWidthSlotNumber the nb slots for spectral width.
 470      * @param isFlexGrid              true if flexible grid, false otherwise.
 471      * @return a spectrum assignment object which contains begin and stop index. If
 472      *         no spectrum assignment found, beginIndex = stopIndex = 0
 473      */
 474     private SpectrumAssignment computeBestSpectrumAssignment(BitSet spectrumOccupation, int spectralWidthSlotNumber,
 475             boolean isFlexGrid) {
 476         SpectrumAssignmentBuilder spectrumAssignmentBldr = new SpectrumAssignmentBuilder()
 477             .setBeginIndex(Uint16.valueOf(0))
 478             .setStopIndex(Uint16.valueOf(0))
 479             .setFlexGrid(isFlexGrid);
 480         BitSet referenceBitSet = new BitSet(spectralWidthSlotNumber);
 481         referenceBitSet.set(0, spectralWidthSlotNumber);
 482         int nbSteps = isFlexGrid ? spectralWidthSlotNumber : 1;
 483         //higher is the frequency, smallest is the wavelength number
 484         //in operational, the allocation is done through wavelength starting from the smallest
 485         //so we have to loop from the last element of the spectrum occupation
 486         for (int i = spectrumOccupation.size(); i >= spectralWidthSlotNumber; i -= nbSteps) {
 487             if (spectrumOccupation.get(i - spectralWidthSlotNumber, i).equals(referenceBitSet)) {
 488                 spectrumAssignmentBldr.setBeginIndex(Uint16.valueOf(i - spectralWidthSlotNumber));
 489                 spectrumAssignmentBldr.setStopIndex(Uint16.valueOf(i - 1));
 490                 break;
 491             }
 492         }
 493         return spectrumAssignmentBldr.build();
 494     }
 495 }