tests/daemon/fw/ncc-strategy.t.cpp - NFD - Gitiles

 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
  * Copyright (c) 2014-2016,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
  *                           Washington University in St. Louis,
  *                           Beijing Institute of Technology,
  *                           The University of Memphis.
  *
  * This file is part of NFD (Named Data Networking Forwarding Daemon).
  * See AUTHORS.md for complete list of NFD authors and contributors.
  *
  * NFD is free software: you can redistribute it and/or modify it under the terms
  * of the GNU General Public License as published by the Free Software Foundation,
  * either version 3 of the License, or (at your option) any later version.
  *
  * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
  * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  * PURPOSE.  See the GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License along with
  * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
  */

 #include "fw/ncc-strategy.hpp"
 #include "strategy-tester.hpp"
 #include "topology-tester.hpp"
 #include "tests/daemon/face/dummy-face.hpp"
 #include "tests/limited-io.hpp"

 #include "tests/test-common.hpp"

 namespace nfd {
 namespace fw {
 namespace tests {

 using namespace nfd::tests;

 BOOST_AUTO_TEST_SUITE(Fw)
 BOOST_FIXTURE_TEST_SUITE(TestNccStrategy, UnitTestTimeFixture)

 using fw::NccStrategy;

 // NccStrategy is fairly complex.
 // The most important property is:
 // it remembers which upstream is the fastest to return Data,
 // and favors this upstream in subsequent Interests.
 BOOST_AUTO_TEST_CASE(FavorRespondingUpstream)
 {
   LimitedIo limitedIo(this);
   Forwarder forwarder;
   typedef StrategyTester<NccStrategy> NccStrategyTester;
   shared_ptr<NccStrategyTester> strategy = make_shared<NccStrategyTester>(ref(forwarder));
   strategy->afterAction.connect(bind(&LimitedIo::afterOp, &limitedIo));

   shared_ptr<DummyFace> face1 = make_shared<DummyFace>();
   shared_ptr<DummyFace> face2 = make_shared<DummyFace>();
   shared_ptr<DummyFace> face3 = make_shared<DummyFace>();
   forwarder.addFace(face1);
   forwarder.addFace(face2);
   forwarder.addFace(face3);

   Fib& fib = forwarder.getFib();
   shared_ptr<fib::Entry> fibEntry = fib.insert(Name()).first;
   fibEntry->addNextHop(face1, 10);
   fibEntry->addNextHop(face2, 20);

   StrategyChoice& strategyChoice = forwarder.getStrategyChoice();
   strategyChoice.install(strategy);
   strategyChoice.insert(Name(), strategy->getName());

   Pit& pit = forwarder.getPit();

   // first Interest: strategy knows nothing and follows routing
   shared_ptr<Interest> interest1p = makeInterest("ndn:/0Jm1ajrW/%00");
   Interest& interest1 = *interest1p;
   interest1.setInterestLifetime(time::milliseconds(8000));
   shared_ptr<pit::Entry> pitEntry1 = pit.insert(interest1).first;

   pitEntry1->insertOrUpdateInRecord(face3, interest1);
   strategy->afterReceiveInterest(*face3, interest1, fibEntry, pitEntry1);

   // forwards to face1 because routing says it's best
   // (no io run here: afterReceiveInterest has already sent the Interest)
   BOOST_REQUIRE_EQUAL(strategy->sendInterestHistory.size(), 1);
   BOOST_CHECK_EQUAL(strategy->sendInterestHistory[0].outFaceId, face1->getId());

   // forwards to face2 because face1 doesn't respond
   limitedIo.run(1, time::milliseconds(500), time::milliseconds(10));
   BOOST_REQUIRE_EQUAL(strategy->sendInterestHistory.size(), 2);
   BOOST_CHECK_EQUAL(strategy->sendInterestHistory[1].outFaceId, face2->getId());

   // face2 responds
   shared_ptr<Data> data1p = makeData("ndn:/0Jm1ajrW/%00");
   Data& data1 = *data1p;
   strategy->beforeSatisfyInterest(pitEntry1, *face2, data1);
   this->advanceClocks(time::milliseconds(10), time::milliseconds(500));

   // second Interest: strategy knows face2 is best
   shared_ptr<Interest> interest2p = makeInterest("ndn:/0Jm1ajrW/%00%01");
   Interest& interest2 = *interest2p;
   interest2.setInterestLifetime(time::milliseconds(8000));
   shared_ptr<pit::Entry> pitEntry2 = pit.insert(interest2).first;

   pitEntry2->insertOrUpdateInRecord(face3, interest2);
   strategy->afterReceiveInterest(*face3, interest2, fibEntry, pitEntry2);

   // forwards to face2 because it responds previously
   this->advanceClocks(time::milliseconds(1));
   BOOST_REQUIRE_GE(strategy->sendInterestHistory.size(), 3);
   BOOST_CHECK_EQUAL(strategy->sendInterestHistory[2].outFaceId, face2->getId());
 }

 BOOST_AUTO_TEST_CASE(Bug1853)
 {
   Forwarder forwarder;
   typedef StrategyTester<NccStrategy> NccStrategyTester;
   shared_ptr<NccStrategyTester> strategy = make_shared<NccStrategyTester>(ref(forwarder));

   shared_ptr<DummyFace> face1 = make_shared<DummyFace>();
   shared_ptr<DummyFace> face2 = make_shared<DummyFace>();
   shared_ptr<DummyFace> face3 = make_shared<DummyFace>();
   forwarder.addFace(face1);
   forwarder.addFace(face2);
   forwarder.addFace(face3);

   Fib& fib = forwarder.getFib();
   shared_ptr<fib::Entry> fibEntry = fib.insert(Name()).first;
   fibEntry->addNextHop(face1, 10);

   StrategyChoice& strategyChoice = forwarder.getStrategyChoice();
   strategyChoice.install(strategy);
   strategyChoice.insert(Name(), strategy->getName());

   Pit& pit = forwarder.getPit();

   // first Interest: strategy follows routing and forwards to face1
   shared_ptr<Interest> interest1 = makeInterest("ndn:/nztwIvHX/%00");
   interest1->setInterestLifetime(time::milliseconds(8000));
   shared_ptr<pit::Entry> pitEntry1 = pit.insert(*interest1).first;

   pitEntry1->insertOrUpdateInRecord(face3, *interest1);
   strategy->afterReceiveInterest(*face3, *interest1, fibEntry, pitEntry1);

   this->advanceClocks(time::milliseconds(1));
   BOOST_REQUIRE_EQUAL(strategy->sendInterestHistory.size(), 1);
   BOOST_CHECK_EQUAL(strategy->sendInterestHistory[0].outFaceId, face1->getId());

   // face1 responds
   shared_ptr<Data> data1 = makeData("ndn:/nztwIvHX/%00");
   strategy->beforeSatisfyInterest(pitEntry1, *face1, *data1);
   this->advanceClocks(time::milliseconds(10), time::milliseconds(500));

   // second Interest: bestFace is face1, nUpstreams becomes 0,
   // therefore pitEntryInfo->maxInterval cannot be calculated from deferRange and nUpstreams
   shared_ptr<Interest> interest2 = makeInterest("ndn:/nztwIvHX/%01");
   interest2->setInterestLifetime(time::milliseconds(8000));
   shared_ptr<pit::Entry> pitEntry2 = pit.insert(*interest2).first;

   pitEntry2->insertOrUpdateInRecord(face3, *interest2);
   strategy->afterReceiveInterest(*face3, *interest2, fibEntry, pitEntry2);

   // FIB entry is changed before doPropagate executes
   fibEntry->addNextHop(face2, 20);
   this->advanceClocks(time::milliseconds(10), time::milliseconds(1000));// should not crash
 }

 BOOST_AUTO_TEST_CASE(Bug1961)
 {
   LimitedIo limitedIo(this);
   Forwarder forwarder;
   typedef StrategyTester<NccStrategy> NccStrategyTester;
   shared_ptr<NccStrategyTester> strategy = make_shared<NccStrategyTester>(ref(forwarder));
   strategy->afterAction.connect(bind(&LimitedIo::afterOp, &limitedIo));

   shared_ptr<DummyFace> face1 = make_shared<DummyFace>();
   shared_ptr<DummyFace> face2 = make_shared<DummyFace>();
   shared_ptr<DummyFace> face3 = make_shared<DummyFace>();
   forwarder.addFace(face1);
   forwarder.addFace(face2);
   forwarder.addFace(face3);

   Fib& fib = forwarder.getFib();
   shared_ptr<fib::Entry> fibEntry = fib.insert(Name()).first;
   fibEntry->addNextHop(face1, 10);
   fibEntry->addNextHop(face2, 20);

   StrategyChoice& strategyChoice = forwarder.getStrategyChoice();
   strategyChoice.install(strategy);
   strategyChoice.insert(Name(), strategy->getName());

   Pit& pit = forwarder.getPit();

   // first Interest: strategy forwards to face1 and face2
   shared_ptr<Interest> interest1 = makeInterest("ndn:/seRMz5a6/%00");
   interest1->setInterestLifetime(time::milliseconds(2000));
   shared_ptr<pit::Entry> pitEntry1 = pit.insert(*interest1).first;

   pitEntry1->insertOrUpdateInRecord(face3, *interest1);
   strategy->afterReceiveInterest(*face3, *interest1, fibEntry, pitEntry1);
   limitedIo.run(2 - strategy->sendInterestHistory.size(),
                 time::milliseconds(2000), time::milliseconds(10));
   BOOST_REQUIRE_EQUAL(strategy->sendInterestHistory.size(), 2);
   BOOST_CHECK_EQUAL(strategy->sendInterestHistory[0].outFaceId, face1->getId());
   BOOST_CHECK_EQUAL(strategy->sendInterestHistory[1].outFaceId, face2->getId());

   // face1 responds
   shared_ptr<Data> data1 = makeData("ndn:/seRMz5a6/%00");
   strategy->beforeSatisfyInterest(pitEntry1, *face1, *data1);
   pitEntry1->clearInRecords();
   this->advanceClocks(time::milliseconds(10));
   // face2 also responds
   strategy->beforeSatisfyInterest(pitEntry1, *face2, *data1);
   this->advanceClocks(time::milliseconds(10));

   // second Interest: bestFace should be face 1
   shared_ptr<Interest> interest2 = makeInterest("ndn:/seRMz5a6/%01");
   interest2->setInterestLifetime(time::milliseconds(2000));
   shared_ptr<pit::Entry> pitEntry2 = pit.insert(*interest2).first;

   pitEntry2->insertOrUpdateInRecord(face3, *interest2);
   strategy->afterReceiveInterest(*face3, *interest2, fibEntry, pitEntry2);
   limitedIo.run(3 - strategy->sendInterestHistory.size(),
                 time::milliseconds(2000), time::milliseconds(10));

   BOOST_REQUIRE_GE(strategy->sendInterestHistory.size(), 3);
   BOOST_CHECK_EQUAL(strategy->sendInterestHistory[2].outFaceId, face1->getId());
 }

 BOOST_AUTO_TEST_CASE(Bug1971)
 {
   LimitedIo limitedIo(this);
   Forwarder forwarder;
   typedef StrategyTester<NccStrategy> NccStrategyTester;
   shared_ptr<NccStrategyTester> strategy = make_shared<NccStrategyTester>(ref(forwarder));
   strategy->afterAction.connect(bind(&LimitedIo::afterOp, &limitedIo));

   shared_ptr<DummyFace> face1 = make_shared<DummyFace>();
   shared_ptr<DummyFace> face2 = make_shared<DummyFace>();
   forwarder.addFace(face1);
   forwarder.addFace(face2);

   Fib& fib = forwarder.getFib();
   shared_ptr<fib::Entry> fibEntry = fib.insert(Name()).first;
   fibEntry->addNextHop(face2, 10);

   StrategyChoice& strategyChoice = forwarder.getStrategyChoice();
   strategyChoice.install(strategy);
   strategyChoice.insert(Name(), strategy->getName());

   Pit& pit = forwarder.getPit();

   // first Interest: strategy forwards to face2
   shared_ptr<Interest> interest1 = makeInterest("ndn:/M4mBXCsd");
   interest1->setInterestLifetime(time::milliseconds(2000));
   shared_ptr<pit::Entry> pitEntry1 = pit.insert(*interest1).first;

   pitEntry1->insertOrUpdateInRecord(face1, *interest1);
   strategy->afterReceiveInterest(*face1, *interest1, fibEntry, pitEntry1);
   limitedIo.run(1 - strategy->sendInterestHistory.size(),
                 time::milliseconds(2000), time::milliseconds(10));
   BOOST_REQUIRE_EQUAL(strategy->sendInterestHistory.size(), 1);
   BOOST_CHECK_EQUAL(strategy->sendInterestHistory[0].outFaceId, face2->getId());

   // face2 responds
   shared_ptr<Data> data1 = makeData("ndn:/M4mBXCsd");
   data1->setFreshnessPeriod(time::milliseconds(5));
   strategy->beforeSatisfyInterest(pitEntry1, *face2, *data1);
   pitEntry1->deleteOutRecord(*face2);
   pitEntry1->clearInRecords();
   this->advanceClocks(time::milliseconds(10));

   // similar Interest: strategy should still forward it
   pitEntry1->insertOrUpdateInRecord(face1, *interest1);
   strategy->afterReceiveInterest(*face1, *interest1, fibEntry, pitEntry1);
   limitedIo.run(2 - strategy->sendInterestHistory.size(),
                 time::milliseconds(2000), time::milliseconds(10));
   BOOST_REQUIRE_EQUAL(strategy->sendInterestHistory.size(), 2);
   BOOST_CHECK_EQUAL(strategy->sendInterestHistory[1].outFaceId, face2->getId());
 }

 BOOST_AUTO_TEST_CASE(Bug1998)
 {
   Forwarder forwarder;
   typedef StrategyTester<NccStrategy> NccStrategyTester;
   shared_ptr<NccStrategyTester> strategy = make_shared<NccStrategyTester>(ref(forwarder));

   shared_ptr<DummyFace> face1 = make_shared<DummyFace>();
   shared_ptr<DummyFace> face2 = make_shared<DummyFace>();
   forwarder.addFace(face1);
   forwarder.addFace(face2);

   Fib& fib = forwarder.getFib();
   shared_ptr<fib::Entry> fibEntry = fib.insert(Name()).first;
   fibEntry->addNextHop(face1, 10); // face1 is top-ranked nexthop
   fibEntry->addNextHop(face2, 20);

   StrategyChoice& strategyChoice = forwarder.getStrategyChoice();
   strategyChoice.install(strategy);
   strategyChoice.insert(Name(), strategy->getName());

   Pit& pit = forwarder.getPit();

   // Interest comes from face1, which is sole downstream
   shared_ptr<Interest> interest1 = makeInterest("ndn:/tFy5HzUzD4");
   shared_ptr<pit::Entry> pitEntry1 = pit.insert(*interest1).first;
   pitEntry1->insertOrUpdateInRecord(face1, *interest1);

   strategy->afterReceiveInterest(*face1, *interest1, fibEntry, pitEntry1);

   // Interest shall go to face2, not loop back to face1
   BOOST_REQUIRE_EQUAL(strategy->sendInterestHistory.size(), 1);
   BOOST_CHECK_EQUAL(strategy->sendInterestHistory[0].outFaceId, face2->getId());
 }

 BOOST_AUTO_TEST_CASE_EXPECTED_FAILURES(PredictionAdjustment, 1)
 BOOST_AUTO_TEST_CASE(PredictionAdjustment) // Bug 3411
 {
   /*
    * /----------\
    * | consumer |
    * \----------/
    *     |
    *     |
    *   +---+  5ms  +---+
    *   | A |-------| B |
    *   +---+       +---+
    *     |           |
    *     | 5ms       | 15ms/5ms
    *     |           |
    *   +---+       +---+
    *   | C |-------| D |
    *   +---+ 15ms  +---+
    *         /5ms    |
    *                 |
    *         /----------\
    *         | producer |
    *         \----------/
    */

   TopologyTester topo;
   TopologyNode nodeA = topo.addForwarder("A"),
                nodeB = topo.addForwarder("B"),
                nodeC = topo.addForwarder("C"),
                nodeD = topo.addForwarder("D");

   for (TopologyNode node : {nodeA, nodeB, nodeC, nodeD}) {
     topo.setStrategy<NccStrategy>(node);
   }

   shared_ptr<TopologyLink> linkAB = topo.addLink("AB", time::milliseconds( 5), {nodeA, nodeB}),
                            linkAC = topo.addLink("AC", time::milliseconds( 5), {nodeA, nodeC}),
                            linkBD = topo.addLink("BD", time::milliseconds(15), {nodeB, nodeD}),
                            linkCD = topo.addLink("CD", time::milliseconds(15), {nodeC, nodeD});

   topo.registerPrefix(nodeA, linkAB->getFace(nodeA), "ndn:/P");
   topo.registerPrefix(nodeA, linkAC->getFace(nodeA), "ndn:/P");
   topo.registerPrefix(nodeB, linkBD->getFace(nodeB), "ndn:/P");
   topo.registerPrefix(nodeC, linkCD->getFace(nodeC), "ndn:/P");

   shared_ptr<TopologyAppLink> producer = topo.addAppFace("producer", nodeD, "ndn:/P");
   topo.addEchoProducer(producer->getClientFace());

   shared_ptr<TopologyAppLink> consumer = topo.addAppFace("consumer", nodeA);
   topo.addIntervalConsumer(consumer->getClientFace(), "ndn:/P",
                            time::milliseconds(100), 300);

   auto getMeInfo = [&] () -> shared_ptr<NccStrategy::MeasurementsEntryInfo> {
     Measurements& measurements = topo.getForwarder(nodeA).getMeasurements();
     shared_ptr<measurements::Entry> me = measurements.findExactMatch("ndn:/P");
     return me == nullptr ? nullptr : me->getStrategyInfo<NccStrategy::MeasurementsEntryInfo>();
   };

   // NccStrategy starts with an exploration period when the algorithm adjusts
   // its prediction to converge near the path RTT.
   bool isExplorationFinished = false;
   const time::milliseconds TRUE_RTT1(40);
   bool isLastPredictionUnder = true;
   int nPredictionCrossings = 0;
   for (int i = 0; i < 10000; ++i) {
     this->advanceClocks(time::milliseconds(5));
     auto meInfo = getMeInfo();
     if (meInfo == nullptr) {
       continue;
     }

     if ((isLastPredictionUnder && meInfo->prediction > TRUE_RTT1) ||
         (!isLastPredictionUnder && meInfo->prediction < TRUE_RTT1)) {
       isLastPredictionUnder = !isLastPredictionUnder;
       if (++nPredictionCrossings > 6) {
         isExplorationFinished = true;
         BOOST_TEST_MESSAGE("exploration finishes after " << (i * 5) << "ms");
         break;
       }
     }
   }
   BOOST_REQUIRE_MESSAGE(isExplorationFinished, "exploration does not finish in 50000ms");

   // NccStrategy has selected one path as the best.
   // When we reduce the RTT of the other path, ideally it should be selected as the best face.
   // However, this won't happen due to a weakness in NccStrategy.
   // See http://redmine.named-data.net/issues/3411#note-4
   shared_ptr<Face> bestFace1 = getMeInfo()->bestFace.lock();
   if (bestFace1.get() == &linkAB->getFace(nodeA)) {
     linkCD->setDelay(time::milliseconds(5));
   }
   else if (bestFace1.get() == &linkAC->getFace(nodeA)) {
     linkBD->setDelay(time::milliseconds(5));
   }
   else {
     BOOST_FAIL("unexpected best face");
   }

   bool isNewBestChosen = false;
   for (int i = 0; i < 10000; ++i) {
     this->advanceClocks(time::milliseconds(5));
     auto meInfo = getMeInfo();
     if (meInfo == nullptr) {
       continue;
     }

     if (meInfo->bestFace.lock() != bestFace1) {
       isNewBestChosen = true;
       BOOST_TEST_MESSAGE("new best face is found after " << (i * 5) << "ms");
       break;
     }
   }
   BOOST_CHECK_MESSAGE(isNewBestChosen, "new best face is not found in 50000ms"); // expected failure
 }

 BOOST_AUTO_TEST_SUITE_END() // TestNccStrategy
 BOOST_AUTO_TEST_SUITE_END() // Fw

 } // namespace tests
 } // namespace fw
 } // namespace nfd
	/* -- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -- */
	/**
	* Copyright (c) 2014-2016, Regents of the University of California,
	* Arizona Board of Regents,
	* Colorado State University,
	* University Pierre & Marie Curie, Sorbonne University,
	* Washington University in St. Louis,
	* Beijing Institute of Technology,
	* The University of Memphis.
	*
	* This file is part of NFD (Named Data Networking Forwarding Daemon).
	* See AUTHORS.md for complete list of NFD authors and contributors.
	*
	* NFD is free software: you can redistribute it and/or modify it under the terms
	* of the GNU General Public License as published by the Free Software Foundation,
	* either version 3 of the License, or (at your option) any later version.
	*
	* NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
	* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
	* PURPOSE. See the GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License along with
	* NFD, e.g., in COPYING.md file. If not, see <http://www.gnu.org/licenses/>.
	*/

	#include "fw/ncc-strategy.hpp"
	#include "strategy-tester.hpp"
	#include "topology-tester.hpp"
	#include "tests/daemon/face/dummy-face.hpp"
	#include "tests/limited-io.hpp"

	#include "tests/test-common.hpp"

	namespace nfd {
	namespace fw {
	namespace tests {

	using namespace nfd::tests;

	BOOST_AUTO_TEST_SUITE(Fw)
	BOOST_FIXTURE_TEST_SUITE(TestNccStrategy, UnitTestTimeFixture)

	using fw::NccStrategy;

	// NccStrategy is fairly complex.
	// The most important property is:
	// it remembers which upstream is the fastest to return Data,
	// and favors this upstream in subsequent Interests.
	BOOST_AUTO_TEST_CASE(FavorRespondingUpstream)
	{
	LimitedIo limitedIo(this);
	Forwarder forwarder;
	typedef StrategyTester<NccStrategy> NccStrategyTester;
	shared_ptr<NccStrategyTester> strategy = make_shared<NccStrategyTester>(ref(forwarder));
	strategy->afterAction.connect(bind(&LimitedIo::afterOp, &limitedIo));

	shared_ptr<DummyFace> face1 = make_shared<DummyFace>();
	shared_ptr<DummyFace> face2 = make_shared<DummyFace>();
	shared_ptr<DummyFace> face3 = make_shared<DummyFace>();
	forwarder.addFace(face1);
	forwarder.addFace(face2);
	forwarder.addFace(face3);

	Fib& fib = forwarder.getFib();
	shared_ptr<fib::Entry> fibEntry = fib.insert(Name()).first;
	fibEntry->addNextHop(face1, 10);
	fibEntry->addNextHop(face2, 20);

	StrategyChoice& strategyChoice = forwarder.getStrategyChoice();
	strategyChoice.install(strategy);
	strategyChoice.insert(Name(), strategy->getName());

	Pit& pit = forwarder.getPit();

	// first Interest: strategy knows nothing and follows routing
	shared_ptr<Interest> interest1p = makeInterest("ndn:/0Jm1ajrW/%00");
	Interest& interest1 = *interest1p;
	interest1.setInterestLifetime(time::milliseconds(8000));
	shared_ptr<pit::Entry> pitEntry1 = pit.insert(interest1).first;

	pitEntry1->insertOrUpdateInRecord(face3, interest1);
	strategy->afterReceiveInterest(*face3, interest1, fibEntry, pitEntry1);

	// forwards to face1 because routing says it's best
	// (no io run here: afterReceiveInterest has already sent the Interest)
	BOOST_REQUIRE_EQUAL(strategy->sendInterestHistory.size(), 1);
	BOOST_CHECK_EQUAL(strategy->sendInterestHistory[0].outFaceId, face1->getId());

	// forwards to face2 because face1 doesn't respond
	limitedIo.run(1, time::milliseconds(500), time::milliseconds(10));
	BOOST_REQUIRE_EQUAL(strategy->sendInterestHistory.size(), 2);
	BOOST_CHECK_EQUAL(strategy->sendInterestHistory[1].outFaceId, face2->getId());

	// face2 responds
	shared_ptr<Data> data1p = makeData("ndn:/0Jm1ajrW/%00");
	Data& data1 = *data1p;
	strategy->beforeSatisfyInterest(pitEntry1, *face2, data1);
	this->advanceClocks(time::milliseconds(10), time::milliseconds(500));

	// second Interest: strategy knows face2 is best
	shared_ptr<Interest> interest2p = makeInterest("ndn:/0Jm1ajrW/%00%01");
	Interest& interest2 = *interest2p;
	interest2.setInterestLifetime(time::milliseconds(8000));
	shared_ptr<pit::Entry> pitEntry2 = pit.insert(interest2).first;

	pitEntry2->insertOrUpdateInRecord(face3, interest2);
	strategy->afterReceiveInterest(*face3, interest2, fibEntry, pitEntry2);

	// forwards to face2 because it responds previously
	this->advanceClocks(time::milliseconds(1));
	BOOST_REQUIRE_GE(strategy->sendInterestHistory.size(), 3);
	BOOST_CHECK_EQUAL(strategy->sendInterestHistory[2].outFaceId, face2->getId());
	}

	BOOST_AUTO_TEST_CASE(Bug1853)
	{
	Forwarder forwarder;
	typedef StrategyTester<NccStrategy> NccStrategyTester;
	shared_ptr<NccStrategyTester> strategy = make_shared<NccStrategyTester>(ref(forwarder));

	shared_ptr<DummyFace> face1 = make_shared<DummyFace>();
	shared_ptr<DummyFace> face2 = make_shared<DummyFace>();
	shared_ptr<DummyFace> face3 = make_shared<DummyFace>();
	forwarder.addFace(face1);
	forwarder.addFace(face2);
	forwarder.addFace(face3);

	Fib& fib = forwarder.getFib();
	shared_ptr<fib::Entry> fibEntry = fib.insert(Name()).first;
	fibEntry->addNextHop(face1, 10);

	StrategyChoice& strategyChoice = forwarder.getStrategyChoice();
	strategyChoice.install(strategy);
	strategyChoice.insert(Name(), strategy->getName());

	Pit& pit = forwarder.getPit();

	// first Interest: strategy follows routing and forwards to face1
	shared_ptr<Interest> interest1 = makeInterest("ndn:/nztwIvHX/%00");
	interest1->setInterestLifetime(time::milliseconds(8000));
	shared_ptr<pit::Entry> pitEntry1 = pit.insert(*interest1).first;

	pitEntry1->insertOrUpdateInRecord(face3, *interest1);
	strategy->afterReceiveInterest(face3, interest1, fibEntry, pitEntry1);

	this->advanceClocks(time::milliseconds(1));
	BOOST_REQUIRE_EQUAL(strategy->sendInterestHistory.size(), 1);
	BOOST_CHECK_EQUAL(strategy->sendInterestHistory[0].outFaceId, face1->getId());

	// face1 responds
	shared_ptr<Data> data1 = makeData("ndn:/nztwIvHX/%00");
	strategy->beforeSatisfyInterest(pitEntry1, face1, data1);
	this->advanceClocks(time::milliseconds(10), time::milliseconds(500));

	// second Interest: bestFace is face1, nUpstreams becomes 0,
	// therefore pitEntryInfo->maxInterval cannot be calculated from deferRange and nUpstreams
	shared_ptr<Interest> interest2 = makeInterest("ndn:/nztwIvHX/%01");
	interest2->setInterestLifetime(time::milliseconds(8000));
	shared_ptr<pit::Entry> pitEntry2 = pit.insert(*interest2).first;

	pitEntry2->insertOrUpdateInRecord(face3, *interest2);
	strategy->afterReceiveInterest(face3, interest2, fibEntry, pitEntry2);

	// FIB entry is changed before doPropagate executes
	fibEntry->addNextHop(face2, 20);
	this->advanceClocks(time::milliseconds(10), time::milliseconds(1000));// should not crash
	}

	BOOST_AUTO_TEST_CASE(Bug1961)
	{
	LimitedIo limitedIo(this);
	Forwarder forwarder;
	typedef StrategyTester<NccStrategy> NccStrategyTester;
	shared_ptr<NccStrategyTester> strategy = make_shared<NccStrategyTester>(ref(forwarder));
	strategy->afterAction.connect(bind(&LimitedIo::afterOp, &limitedIo));

	shared_ptr<DummyFace> face1 = make_shared<DummyFace>();
	shared_ptr<DummyFace> face2 = make_shared<DummyFace>();
	shared_ptr<DummyFace> face3 = make_shared<DummyFace>();
	forwarder.addFace(face1);
	forwarder.addFace(face2);
	forwarder.addFace(face3);

	Fib& fib = forwarder.getFib();
	shared_ptr<fib::Entry> fibEntry = fib.insert(Name()).first;
	fibEntry->addNextHop(face1, 10);
	fibEntry->addNextHop(face2, 20);

	StrategyChoice& strategyChoice = forwarder.getStrategyChoice();
	strategyChoice.install(strategy);
	strategyChoice.insert(Name(), strategy->getName());

	Pit& pit = forwarder.getPit();

	// first Interest: strategy forwards to face1 and face2
	shared_ptr<Interest> interest1 = makeInterest("ndn:/seRMz5a6/%00");
	interest1->setInterestLifetime(time::milliseconds(2000));
	shared_ptr<pit::Entry> pitEntry1 = pit.insert(*interest1).first;

	pitEntry1->insertOrUpdateInRecord(face3, *interest1);
	strategy->afterReceiveInterest(face3, interest1, fibEntry, pitEntry1);
	limitedIo.run(2 - strategy->sendInterestHistory.size(),
	time::milliseconds(2000), time::milliseconds(10));
	BOOST_REQUIRE_EQUAL(strategy->sendInterestHistory.size(), 2);
	BOOST_CHECK_EQUAL(strategy->sendInterestHistory[0].outFaceId, face1->getId());
	BOOST_CHECK_EQUAL(strategy->sendInterestHistory[1].outFaceId, face2->getId());

	// face1 responds
	shared_ptr<Data> data1 = makeData("ndn:/seRMz5a6/%00");
	strategy->beforeSatisfyInterest(pitEntry1, face1, data1);
	pitEntry1->clearInRecords();
	this->advanceClocks(time::milliseconds(10));
	// face2 also responds
	strategy->beforeSatisfyInterest(pitEntry1, face2, data1);
	this->advanceClocks(time::milliseconds(10));

	// second Interest: bestFace should be face 1
	shared_ptr<Interest> interest2 = makeInterest("ndn:/seRMz5a6/%01");
	interest2->setInterestLifetime(time::milliseconds(2000));
	shared_ptr<pit::Entry> pitEntry2 = pit.insert(*interest2).first;

	pitEntry2->insertOrUpdateInRecord(face3, *interest2);
	strategy->afterReceiveInterest(face3, interest2, fibEntry, pitEntry2);
	limitedIo.run(3 - strategy->sendInterestHistory.size(),
	time::milliseconds(2000), time::milliseconds(10));

	BOOST_REQUIRE_GE(strategy->sendInterestHistory.size(), 3);
	BOOST_CHECK_EQUAL(strategy->sendInterestHistory[2].outFaceId, face1->getId());
	}

	BOOST_AUTO_TEST_CASE(Bug1971)
	{
	LimitedIo limitedIo(this);
	Forwarder forwarder;
	typedef StrategyTester<NccStrategy> NccStrategyTester;
	shared_ptr<NccStrategyTester> strategy = make_shared<NccStrategyTester>(ref(forwarder));
	strategy->afterAction.connect(bind(&LimitedIo::afterOp, &limitedIo));

	shared_ptr<DummyFace> face1 = make_shared<DummyFace>();
	shared_ptr<DummyFace> face2 = make_shared<DummyFace>();
	forwarder.addFace(face1);
	forwarder.addFace(face2);

	Fib& fib = forwarder.getFib();
	shared_ptr<fib::Entry> fibEntry = fib.insert(Name()).first;
	fibEntry->addNextHop(face2, 10);

	StrategyChoice& strategyChoice = forwarder.getStrategyChoice();
	strategyChoice.install(strategy);
	strategyChoice.insert(Name(), strategy->getName());

	Pit& pit = forwarder.getPit();

	// first Interest: strategy forwards to face2
	shared_ptr<Interest> interest1 = makeInterest("ndn:/M4mBXCsd");
	interest1->setInterestLifetime(time::milliseconds(2000));
	shared_ptr<pit::Entry> pitEntry1 = pit.insert(*interest1).first;

	pitEntry1->insertOrUpdateInRecord(face1, *interest1);
	strategy->afterReceiveInterest(face1, interest1, fibEntry, pitEntry1);
	limitedIo.run(1 - strategy->sendInterestHistory.size(),
	time::milliseconds(2000), time::milliseconds(10));
	BOOST_REQUIRE_EQUAL(strategy->sendInterestHistory.size(), 1);
	BOOST_CHECK_EQUAL(strategy->sendInterestHistory[0].outFaceId, face2->getId());

	// face2 responds
	shared_ptr<Data> data1 = makeData("ndn:/M4mBXCsd");
	data1->setFreshnessPeriod(time::milliseconds(5));
	strategy->beforeSatisfyInterest(pitEntry1, face2, data1);
	pitEntry1->deleteOutRecord(*face2);
	pitEntry1->clearInRecords();
	this->advanceClocks(time::milliseconds(10));

	// similar Interest: strategy should still forward it
	pitEntry1->insertOrUpdateInRecord(face1, *interest1);
	strategy->afterReceiveInterest(face1, interest1, fibEntry, pitEntry1);
	limitedIo.run(2 - strategy->sendInterestHistory.size(),
	time::milliseconds(2000), time::milliseconds(10));
	BOOST_REQUIRE_EQUAL(strategy->sendInterestHistory.size(), 2);
	BOOST_CHECK_EQUAL(strategy->sendInterestHistory[1].outFaceId, face2->getId());
	}

	BOOST_AUTO_TEST_CASE(Bug1998)
	{
	Forwarder forwarder;
	typedef StrategyTester<NccStrategy> NccStrategyTester;
	shared_ptr<NccStrategyTester> strategy = make_shared<NccStrategyTester>(ref(forwarder));

	shared_ptr<DummyFace> face1 = make_shared<DummyFace>();
	shared_ptr<DummyFace> face2 = make_shared<DummyFace>();
	forwarder.addFace(face1);
	forwarder.addFace(face2);

	Fib& fib = forwarder.getFib();
	shared_ptr<fib::Entry> fibEntry = fib.insert(Name()).first;
	fibEntry->addNextHop(face1, 10); // face1 is top-ranked nexthop
	fibEntry->addNextHop(face2, 20);

	StrategyChoice& strategyChoice = forwarder.getStrategyChoice();
	strategyChoice.install(strategy);
	strategyChoice.insert(Name(), strategy->getName());

	Pit& pit = forwarder.getPit();

	// Interest comes from face1, which is sole downstream
	shared_ptr<Interest> interest1 = makeInterest("ndn:/tFy5HzUzD4");
	shared_ptr<pit::Entry> pitEntry1 = pit.insert(*interest1).first;
	pitEntry1->insertOrUpdateInRecord(face1, *interest1);

	strategy->afterReceiveInterest(face1, interest1, fibEntry, pitEntry1);

	// Interest shall go to face2, not loop back to face1
	BOOST_REQUIRE_EQUAL(strategy->sendInterestHistory.size(), 1);
	BOOST_CHECK_EQUAL(strategy->sendInterestHistory[0].outFaceId, face2->getId());
	}

	BOOST_AUTO_TEST_CASE_EXPECTED_FAILURES(PredictionAdjustment, 1)
	BOOST_AUTO_TEST_CASE(PredictionAdjustment) // Bug 3411
	{
	/*
	* /----------\
	* \| consumer \|
	* \----------/
	* \|
	* \|
	* +---+ 5ms +---+
	* \| A \|-------\| B \|
	* +---+ +---+
	* \| \|
	* \| 5ms \| 15ms/5ms
	* \| \|
	* +---+ +---+
	* \| C \|-------\| D \|
	* +---+ 15ms +---+
	* /5ms \|
	* \|
	* /----------\
	* \| producer \|
	* \----------/
	*/

	TopologyTester topo;
	TopologyNode nodeA = topo.addForwarder("A"),
	nodeB = topo.addForwarder("B"),
	nodeC = topo.addForwarder("C"),
	nodeD = topo.addForwarder("D");

	for (TopologyNode node : {nodeA, nodeB, nodeC, nodeD}) {
	topo.setStrategy<NccStrategy>(node);
	}

	shared_ptr<TopologyLink> linkAB = topo.addLink("AB", time::milliseconds( 5), {nodeA, nodeB}),
	linkAC = topo.addLink("AC", time::milliseconds( 5), {nodeA, nodeC}),
	linkBD = topo.addLink("BD", time::milliseconds(15), {nodeB, nodeD}),
	linkCD = topo.addLink("CD", time::milliseconds(15), {nodeC, nodeD});

	topo.registerPrefix(nodeA, linkAB->getFace(nodeA), "ndn:/P");
	topo.registerPrefix(nodeA, linkAC->getFace(nodeA), "ndn:/P");
	topo.registerPrefix(nodeB, linkBD->getFace(nodeB), "ndn:/P");
	topo.registerPrefix(nodeC, linkCD->getFace(nodeC), "ndn:/P");

	shared_ptr<TopologyAppLink> producer = topo.addAppFace("producer", nodeD, "ndn:/P");
	topo.addEchoProducer(producer->getClientFace());

	shared_ptr<TopologyAppLink> consumer = topo.addAppFace("consumer", nodeA);
	topo.addIntervalConsumer(consumer->getClientFace(), "ndn:/P",
	time::milliseconds(100), 300);

	auto getMeInfo = [&] () -> shared_ptr<NccStrategy::MeasurementsEntryInfo> {
	Measurements& measurements = topo.getForwarder(nodeA).getMeasurements();
	shared_ptr<measurements::Entry> me = measurements.findExactMatch("ndn:/P");
	return me == nullptr ? nullptr : me->getStrategyInfo<NccStrategy::MeasurementsEntryInfo>();
	};

	// NccStrategy starts with an exploration period when the algorithm adjusts
	// its prediction to converge near the path RTT.
	bool isExplorationFinished = false;
	const time::milliseconds TRUE_RTT1(40);
	bool isLastPredictionUnder = true;
	int nPredictionCrossings = 0;
	for (int i = 0; i < 10000; ++i) {
	this->advanceClocks(time::milliseconds(5));
	auto meInfo = getMeInfo();
	if (meInfo == nullptr) {
	continue;
	}

	if ((isLastPredictionUnder && meInfo->prediction > TRUE_RTT1) \|\|
	(!isLastPredictionUnder && meInfo->prediction < TRUE_RTT1)) {
	isLastPredictionUnder = !isLastPredictionUnder;
	if (++nPredictionCrossings > 6) {
	isExplorationFinished = true;
	BOOST_TEST_MESSAGE("exploration finishes after " << (i * 5) << "ms");
	break;
	}
	}
	}
	BOOST_REQUIRE_MESSAGE(isExplorationFinished, "exploration does not finish in 50000ms");

	// NccStrategy has selected one path as the best.
	// When we reduce the RTT of the other path, ideally it should be selected as the best face.
	// However, this won't happen due to a weakness in NccStrategy.
	// See http://redmine.named-data.net/issues/3411#note-4
	shared_ptr<Face> bestFace1 = getMeInfo()->bestFace.lock();
	if (bestFace1.get() == &linkAB->getFace(nodeA)) {
	linkCD->setDelay(time::milliseconds(5));
	}
	else if (bestFace1.get() == &linkAC->getFace(nodeA)) {
	linkBD->setDelay(time::milliseconds(5));
	}
	else {
	BOOST_FAIL("unexpected best face");
	}

	bool isNewBestChosen = false;
	for (int i = 0; i < 10000; ++i) {
	this->advanceClocks(time::milliseconds(5));
	auto meInfo = getMeInfo();
	if (meInfo == nullptr) {
	continue;
	}

	if (meInfo->bestFace.lock() != bestFace1) {
	isNewBestChosen = true;
	BOOST_TEST_MESSAGE("new best face is found after " << (i * 5) << "ms");
	break;
	}
	}
	BOOST_CHECK_MESSAGE(isNewBestChosen, "new best face is not found in 50000ms"); // expected failure
	}

	BOOST_AUTO_TEST_SUITE_END() // TestNccStrategy
	BOOST_AUTO_TEST_SUITE_END() // Fw

	} // namespace tests
	} // namespace fw
	} // namespace nfd