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