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