001/******************************************************************************* 002 * Copyright (c) 2016 Pablo Pavon Mariņo. 003 * All rights reserved. This program and the accompanying materials 004 * are made available under the terms of the GNU Lesser Public License v2.1 005 * which accompanies this distribution, and is available at 006 * http://www.gnu.org/licenses/lgpl.html 007 ******************************************************************************/ 008 009 010 011 012 013 014 015 016 017 018package com.net2plan.examples.ocnbook.offline; 019 020import java.util.Collections; 021import java.util.List; 022import java.util.Map; 023 024import cern.colt.matrix.tdouble.DoubleFactory1D; 025import cern.colt.matrix.tdouble.DoubleMatrix1D; 026 027import com.jom.OptimizationProblem; 028import com.net2plan.interfaces.networkDesign.Demand; 029import com.net2plan.interfaces.networkDesign.IAlgorithm; 030import com.net2plan.interfaces.networkDesign.Net2PlanException; 031import com.net2plan.interfaces.networkDesign.NetPlan; 032import com.net2plan.interfaces.networkDesign.ProtectionSegment; 033import com.net2plan.interfaces.networkDesign.Route; 034import com.net2plan.utils.Constants.RoutingType; 035import com.net2plan.utils.InputParameter; 036import com.net2plan.utils.Triple; 037 038/** 039 * Solves several variants of unicast routing problems with 1+1 protection, with flow-path formulations 040 * @net2plan.description 041 * @net2plan.keywords JOM, Flow-path formulation, Flow assignment (FA), Network recovery: protection 042 * @net2plan.ocnbooksections Section 4.2, Section 4.6.6 043 * @net2plan.inputParameters 044 * @author Pablo Pavon-Marino 045 */ 046public class Offline_fa_xp11PathProtection implements IAlgorithm 047{ 048 private InputParameter k = new InputParameter ("k", (int) 5 , "Maximum number of admissible paths per demand" , 1 , Integer.MAX_VALUE); 049 private InputParameter shortestPathType = new InputParameter ("shortestPathType", "#select# hops km" , "Criteria to compute the shortest path. Valid values: 'hops' or 'km'"); 050 private InputParameter maxLengthInKm = new InputParameter ("maxLengthInKm", (double) 2000 , "Paths longer than this are considered not admissible. A non-positive number means this limit does not exist"); 051 private InputParameter optimizationTarget = new InputParameter ("optimizationTarget", "#select# min-av-num-hops minimax-link-utilization maximin-link-idle-capacity" , "Type of optimization target. Choose among minimize the average number of hops, minimize the highest link utilization, maximize the lowest link idle capacity"); 052 private InputParameter solverName = new InputParameter ("solverName", "#select# glpk cplex ipopt", "The solver name to be used by JOM. GLPK and IPOPT are free, CPLEX commercial. GLPK and CPLEX solve linear problems w/w.o integer contraints. IPOPT is can solve nonlinear problems (if convex, returns global optimum), but cannot handle integer constraints"); 053 private InputParameter solverLibraryName = new InputParameter ("solverLibraryName", "", "The solver library full or relative path, to be used by JOM. Leave blank to use JOM default."); 054 private InputParameter maxSolverTimeInSeconds = new InputParameter ("maxSolverTimeInSeconds", (double) -1 , "Maximum time granted to the solver to solve the problem. If this time expires, the solver returns the best solution found so far (if a feasible solution is found)"); 055 private InputParameter type11 = new InputParameter ("type11", "#select# linkDisjoint srgDisjoint" , "Type of 1+1 protection: 1+1 link disjoint (primary and backup paths have no link in common), and 1+1 srg disjoint (primary and backup paths have no SRG in common)"); 056 057 @Override 058 public String executeAlgorithm(NetPlan netPlan, Map<String, String> algorithmParameters, Map<String, String> net2planParameters) 059 { 060 /* Initialize all InputParameter objects defined in this object (this uses Java reflection) */ 061 InputParameter.initializeAllInputParameterFieldsOfObject(this, algorithmParameters); 062 if (!shortestPathType.getString().equalsIgnoreCase("km") && !shortestPathType.getString().equalsIgnoreCase("hops")) 063 throw new Net2PlanException("Wrong shortestPathType parameter"); 064 if (type11.getString ().equalsIgnoreCase("srgDisjoint") && (netPlan.getNumberOfSRGs() == 0)) throw new Net2PlanException("No SRG was defined"); 065 066 /* Basic checks */ 067 final int N = netPlan.getNumberOfNodes(); 068 final int E = netPlan.getNumberOfLinks(); 069 final int D = netPlan.getNumberOfDemands(); 070 final int S = netPlan.getNumberOfSRGs(); 071 final double PRECISION_FACTOR = Double.parseDouble(net2planParameters.get("precisionFactor")); 072 if (N == 0 || D == 0 || E == 0) throw new Net2PlanException("This algorithm requires a topology with links, and a demand set"); 073 074 /* Remove all unicast routed traffic. Any multicast routed traffic is kept */ 075 netPlan.removeAllUnicastRoutingInformation(); 076 netPlan.setRoutingType(RoutingType.SOURCE_ROUTING); 077 078 /* Add all the k-shortest candidate routes to the netPlan object carrying no traffic */ 079 final DoubleMatrix1D linkCostVector = shortestPathType.getString().equalsIgnoreCase("hops")? DoubleFactory1D.dense.make (E , 1.0) : netPlan.getVectorLinkLengthInKm(); 080 081 netPlan.addRoutesFromCandidatePathList(linkCostVector.toArray() , "K", Integer.toString(k.getInt ()), "maxLengthInKm", Double.toString(maxLengthInKm.getDouble () > 0? maxLengthInKm.getDouble () : Double.MAX_VALUE)); 082 final int P = netPlan.getNumberOfRoutes(); 083 084 /* Create the optimization problem object (JOM library) */ 085 OptimizationProblem op = new OptimizationProblem(); 086 op.setInputParameter("u_e", netPlan.getVectorLinkSpareCapacity(), "row"); /* for each link, its unused capacity (the one not used by any mulitcast trees) */ 087 op.setInputParameter("A_ep", netPlan.getMatrixLink2RouteAssignment()); /* 1 in position (e,p) if link e is traversed by path p, 0 otherwise */ 088 op.setInputParameter("A_dp", netPlan.getMatrixDemand2RouteAssignment()); /* 1 in position (d,p) if demand d is served by path p, 0 otherwise */ 089 op.setInputParameter("h_d", netPlan.getVectorDemandOfferedTraffic(), "row"); /* for each demand, its offered traffic */ 090 op.setInputParameter("h_p", netPlan.getVectorRouteOfferedTrafficOfAssociatedDemand () , "row"); /* for each path, the offered traffic of its demand */ 091 092 if (type11.getString ().equalsIgnoreCase("linkDisjoint")) 093 op.setInputParameter("A_ps", netPlan.getMatrixLink2RouteAssignment().viewDice ()); /* 1 in position (p,s) if link s is traversed by path p, 0 otherwise */ 094 else if (type11.getString ().equalsIgnoreCase("srgDisjoint")) 095 op.setInputParameter("A_ps", netPlan.getMatrixRoute2SRGAffecting()); /* 1 in position (p,s) if srg s is affecting path p, 0 otherwise */ 096 097 /* Common decision variables */ 098 op.addDecisionVariable("xx_p", true , new int[] { 1, P }, 0, 1); /* 1 if primary path of demand d(p) that is carried by p */ 099 op.addDecisionVariable("bb_p", true , new int[] { 1, P }, 0, 1); /* 1 if backup path of demand d(p) that is carried by p */ 100 101 if (optimizationTarget.getString ().equals ("min-av-num-hops")) 102 { 103 op.setInputParameter("l_p", netPlan.getVectorRouteNumberOfLinks() , "row"); /* for each path, the number of traversed links */ 104 op.setObjectiveFunction("minimize", "sum (l_p .* h_p .* (xx_p + bb_p))"); /* sum of the traffic in the links, proportional to the average number of hops */ 105 op.addConstraint("A_ep * (h_p .* (xx_p + bb_p))' <= u_e'"); /* the traffic in each link cannot exceed its capacity */ 106 } 107 else if (optimizationTarget.getString ().equals ("minimax-link-utilization")) 108 { 109 op.addDecisionVariable("rho", false, new int[] { 1, 1 }, 0, 1); /* worse case link utilization */ 110 op.setObjectiveFunction("minimize", "rho"); 111 op.addConstraint("A_ep * (h_p .* (xx_p + bb_p))' <= rho * u_e'"); /* the traffic in each link cannot exceed its capacity. sets rho as the worse case utilization */ 112 } 113 else if (optimizationTarget.getString ().equals ("maximin-link-idle-capacity")) 114 { 115 op.addDecisionVariable("u", false, new int[] { 1, 1 }, 0, Double.MAX_VALUE); /* worse case link idle capacity */ 116 op.setObjectiveFunction("maximize", "u"); 117 op.addConstraint("A_ep * (h_p .* (xx_p + bb_p))' <= -u + u_e'"); /* the traffic in each link cannot exceed its capacity. sets u as the worse case idle capacity */ 118 } 119 else throw new Net2PlanException ("Unknown optimization target " + optimizationTarget.getString()); 120 121 op.addConstraint("A_dp * xx_p' == 1"); /* for each demand, one primary path exists */ 122 op.addConstraint("A_dp * bb_p' == 1"); /* for each demand, one backup path exists */ 123 op.addConstraint("A_dp * diag(xx_p + bb_p) * A_ps <= 1"); /* primary and backup are link or srg disjoint (depending on what is needed) */ 124 125 /* Call the solver to solve the problem */ 126 op.solve(solverName.getString (), "solverLibraryName", solverLibraryName.getString () , "maxSolverTimeInSeconds" , maxSolverTimeInSeconds.getDouble ()); 127 128 /* If no solution is found, quit */ 129 if (op.feasibleSolutionDoesNotExist()) throw new Net2PlanException("The problem has no feasible solution"); 130 if (!op.solutionIsFeasible()) throw new Net2PlanException("A feasible solution was not found"); 131 132 /* Retrieve the optimum solutions */ 133 double [] xx_p = op.getPrimalSolution("xx_p").to1DArray(); 134 double [] bb_p = op.getPrimalSolution("bb_p").to1DArray(); 135 136 for (Demand d : netPlan.getDemands ()) 137 { 138 Route primary = null; Route backup = null; 139 for (Route r : d.getRoutes()) { if (xx_p [r.getIndex ()] == 1) primary = r; if (bb_p [r.getIndex ()] == 1) backup = r; } 140 ProtectionSegment segment = netPlan.addProtectionSegment(backup.getSeqLinksRealPath() , d.getOfferedTraffic() , null); 141 if (primary == null) throw new RuntimeException ("Bad"); 142 if (backup == null) throw new RuntimeException ("Bad"); 143 primary.setCarriedTraffic(d.getOfferedTraffic() , d.getOfferedTraffic()); 144 primary.addProtectionSegment(segment); 145 } 146 147 netPlan.removeAllRoutesUnused(PRECISION_FACTOR); // routes with zero traffic (or close to zero, with PRECISION_FACTOR tolerance) 148 149 checkSolution(netPlan, type11.getString ()); 150 151 return "Ok!"; 152 } 153 154 @Override 155 public String getDescription() 156 { 157 return "Given a network topology, the capacities in the links, and a set unicast traffic demands, this algorithm permits computing the optimum routing of the traffic with 1+1 protection to each route, solving a variations of the flow-path formulation. Initially, a set of admissible candidate paths are computed for each demand, which can be used as either primary or backup paths. Through a set of input parameters, the user can choose among different optimization targets and constraints."; 158 } 159 160 @Override 161 public List<Triple<String, String, String>> getParameters() 162 { 163 /* Returns the parameter information for all the InputParameter objects defined in this object (uses Java reflection) */ 164 return InputParameter.getInformationAllInputParameterFieldsOfObject(this); 165 } 166 167 private static void checkSolution(NetPlan netPlan, String type11) 168 { 169 if (!netPlan.getLinksOversubscribed().isEmpty()) throw new Net2PlanException("Bad - Some link is oversubscribed (constraint violated)"); 170 if (!netPlan.getDemandsBlocked().isEmpty()) throw new Net2PlanException("Bad - Some demand is blocked (constraint violated)"); 171 172 for (Route route : netPlan.getRoutes()) 173 { 174 if (route.getPotentialBackupProtectionSegments().size () != 1) throw new RuntimeException("Bad"); 175 176 final ProtectionSegment segment = route.getPotentialBackupProtectionSegments().iterator().next(); 177 if (route.getIngressNode() != segment.getOriginNode()) throw new RuntimeException("Bad"); 178 if (route.getEgressNode() != segment.getDestinationNode()) throw new RuntimeException("Bad"); 179 180 if (type11.equalsIgnoreCase("srgDisjoint")) 181 if (!Collections.disjoint(route.getSRGs(), segment.getSRGs())) 182 throw new RuntimeException("Bad"); 183 else if (type11.equalsIgnoreCase("linkDisjoint")) 184 if (!Collections.disjoint(route.getSeqLinksRealPath(), segment.getSeqLinks())) 185 throw new RuntimeException("Bad"); 186 else 187 throw new RuntimeException ("Bad"); 188 } 189 } 190} 191