tests/daemon/fw/access-strategy.t.cpp - ndnSIM/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/access-strategy.hpp"

 #include "tests/test-common.hpp"
 #include "topology-tester.hpp"

 namespace nfd {
 namespace fw {
 namespace tests {

 using namespace nfd::tests;

 // This test suite tests AccessStrategy's behavior as a black box,
 // without accessing its internals.
 //
 // Many test assertions are qualitative rather than quantitative.
 // They capture the design highlights of the strategy without requiring a definite value,
 // so that the test suite is not fragile to minor changes in the strategy implementation.
 //
 // Topology graphes in this test suite are shown in ASCII art,
 // in a style similar to ns-3 and ndnSIM examples.
 // They are enclosed in multi-line comments, which is an intentional violation of
 // code style rule 3.25. This is necessary because some lines ends with '\' which
 // would cause "multi-line comment" compiler warning if '//' comments are used.

 BOOST_AUTO_TEST_SUITE(Fw)
 BOOST_FIXTURE_TEST_SUITE(TestAccessStrategy, UnitTestTimeFixture)

 BOOST_AUTO_TEST_CASE(Registration)
 {
   BOOST_CHECK_EQUAL(Strategy::listRegistered().count(AccessStrategy::getStrategyName()), 1);
 }

 class TwoLaptopsFixture : public UnitTestTimeFixture
 {
 protected:
   TwoLaptopsFixture()
   {
     /*
      *                  +--------+
      *           +----->| router |<------+
      *           |      +--------+       |
      *      10ms |                       | 20ms
      *           v                       v
      *      +---------+             +---------+
      *      | laptopA |             | laptopB |
      *      +---------+             +---------+
      */

     router = topo.addForwarder("R");
     laptopA = topo.addForwarder("A");
     laptopB = topo.addForwarder("B");

     topo.setStrategy<fw::AccessStrategy>(router);

     linkA = topo.addLink("RA", time::milliseconds(10), {router, laptopA});
     linkB = topo.addLink("RB", time::milliseconds(20), {router, laptopB});
   }

 protected:
   TopologyTester topo;

   TopologyNode router;
   TopologyNode laptopA;
   TopologyNode laptopB;
   shared_ptr<TopologyLink> linkA;
   shared_ptr<TopologyLink> linkB;
 };

 BOOST_FIXTURE_TEST_CASE(OneProducer, TwoLaptopsFixture)
 {
   /*
    *             /------------------\
    *             | intervalConsumer |
    *             \------------------/
    *                      ^ v
    *                      | v /laptops/A
    *                      |
    *                      v
    *      /laptops << +--------+ >> /laptops
    *           +----->| router |<------+
    *           |      +--------+       |
    *      10ms |                       | 20ms
    *           v                       v
    *      +---------+             +---------+
    *      | laptopA |             | laptopB |
    *      +---------+             +---------+
    *           ^  v
    *           |  v /laptops/A
    *           v
    *    /--------------\
    *    | echoProducer |
    *    \--------------/
    */

   // two laptops have same prefix in router FIB
   topo.registerPrefix(router, linkA->getFace(router), "ndn:/laptops");
   topo.registerPrefix(router, linkB->getFace(router), "ndn:/laptops");

   shared_ptr<TopologyAppLink> producer = topo.addAppFace("p", laptopA, "ndn:/laptops/A");
   topo.addEchoProducer(producer->getClientFace());

   shared_ptr<TopologyAppLink> consumer = topo.addAppFace("c", router);
   topo.addIntervalConsumer(consumer->getClientFace(), "ndn:/laptops/A",
                            time::milliseconds(100), 100);

   this->advanceClocks(time::milliseconds(5), time::seconds(12));

   // most Interests should be satisfied, and few Interests can go to wrong laptop
   BOOST_CHECK_GE(consumer->getForwarderFace().getCounters().nOutData, 97);
   BOOST_CHECK_GE(linkA->getFace(router).getCounters().nOutInterests, 97);
   BOOST_CHECK_LE(linkB->getFace(router).getCounters().nOutInterests, 5);
 }

 BOOST_FIXTURE_TEST_CASE(FastSlowProducer, TwoLaptopsFixture)
 {
   /*
    *             /------------------\
    *             | intervalConsumer |
    *             \------------------/
    *                      ^ v
    *                      | v /laptops/BOTH
    *                      |
    *                      v
    *      /laptops << +--------+ >> /laptops
    *           +----->| router |<------+
    *           |      +--------+       |
    *      10ms |                       | 20ms
    *           v                       v
    *      +---------+             +---------+
    *      | laptopA |             | laptopB |
    *      +---------+             +---------+
    *           ^  v                    ^  v
    *           |  v /laptops/BOTH      |  v /laptops/BOTH
    *           v                       v
    *    /--------------\        /--------------\
    *    | echoProducer |        | echoProducer |
    *    \--------------/        \--------------/
    */

   // two laptops have same prefix in router FIB
   topo.registerPrefix(router, linkA->getFace(router), "ndn:/laptops");
   topo.registerPrefix(router, linkB->getFace(router), "ndn:/laptops");

   shared_ptr<TopologyAppLink> producerA = topo.addAppFace("pA", laptopA, "ndn:/laptops/BOTH");
   topo.addEchoProducer(producerA->getClientFace());
   shared_ptr<TopologyAppLink> producerB = topo.addAppFace("pB", laptopB, "ndn:/laptops/BOTH");
   topo.addEchoProducer(producerB->getClientFace());

   shared_ptr<TopologyAppLink> consumer = topo.addAppFace("c", router);
   topo.addIntervalConsumer(consumer->getClientFace(), "ndn:/laptops/BOTH",
                            time::milliseconds(100), 100);

   this->advanceClocks(time::milliseconds(5), time::seconds(12));

   // most Interests should be satisfied, and few Interests can go to slower laptopB
   BOOST_CHECK_GE(consumer->getForwarderFace().getCounters().nOutData, 97);
   BOOST_CHECK_GE(linkA->getFace(router).getCounters().nOutInterests, 90);
   BOOST_CHECK_LE(linkB->getFace(router).getCounters().nOutInterests, 15);
 }

 BOOST_FIXTURE_TEST_CASE(ProducerMobility, TwoLaptopsFixture)
 {
   /*
    *           /------------------\                              /------------------\
    *           | intervalConsumer |                              | intervalConsumer |
    *           \------------------/              A               \------------------/
    *                    ^ v                      f                        ^ v
    *                    | v /laptops/M           t                        | v /laptops/M
    *                    |                        e                        |
    *                    v                        r                        v
    *    /laptops << +--------+ >> /laptops                /laptops << +--------+ >> /laptops
    *         +----->| router |<------+           6             +----->| router |<------+
    *         |      +--------+       |                         |      +--------+       |
    *    10ms |                       | 20ms  === s ==>    10ms |                       | 20ms
    *         v                       v           e             v                       v
    *    +---------+             +---------+      c        +---------+             +---------+
    *    | laptopA |             | laptopB |      o        | laptopA |             | laptopB |
    *    +---------+             +---------+      n        +---------+             +---------+
    *         ^  v                                d                                  v  ^
    *         |  v /laptops/M                     s                       /laptops/M v  |
    *         v                                                                         v
    *  /--------------\                                                          /--------------\
    *  | echoProducer |                                                          | echoProducer |
    *  \--------------/                                                          \--------------/
    */

   // two laptops have same prefix in router FIB
   topo.registerPrefix(router, linkA->getFace(router), "ndn:/laptops");
   topo.registerPrefix(router, linkB->getFace(router), "ndn:/laptops");

   shared_ptr<TopologyAppLink> producerA = topo.addAppFace("pA", laptopA, "ndn:/laptops/M");
   topo.addEchoProducer(producerA->getClientFace());
   shared_ptr<TopologyAppLink> producerB = topo.addAppFace("pB", laptopB, "ndn:/laptops/M");
   topo.addEchoProducer(producerB->getClientFace());

   shared_ptr<TopologyAppLink> consumer = topo.addAppFace("c", router);
   topo.addIntervalConsumer(consumer->getClientFace(), "ndn:/laptops/M",
                            time::milliseconds(100), 100);

   // producer is initially on laptopA
   producerB->fail();
   this->advanceClocks(time::milliseconds(5), time::seconds(6));

   // few Interests can go to laptopB
   BOOST_CHECK_LE(linkB->getFace(router).getCounters().nOutInterests, 5);

   // producer moves to laptopB
   producerA->fail();
   producerB->recover();
   PacketCounter::rep nInterestsToA_beforeMove = linkA->getFace(router).getCounters().nOutInterests;
   this->advanceClocks(time::milliseconds(5), time::seconds(6));

   // few additional Interests can go to laptopA
   BOOST_CHECK_LE(linkA->getFace(router).getCounters().nOutInterests - nInterestsToA_beforeMove, 5);

   // most Interests should be satisfied
   BOOST_CHECK_GE(consumer->getForwarderFace().getCounters().nOutData, 97);
 }

 BOOST_FIXTURE_TEST_CASE(Bidirectional, TwoLaptopsFixture)
 {
   /*
    *                         /laptops << +--------+ >> /laptops
    *                              +----->| router |<------+
    *                              |      +--------+       |
    *                      ^  10ms |                       | 20ms  ^
    *                    / ^       v                       v       ^ /
    *                         +---------+             +---------+
    *                  +----->| laptopA |             | laptopB |<------------+
    *                  |      +---------+             +---------+             |
    *                  |           ^  v /laptops/A         ^  v /laptops/B    |
    *               ^  |           |  v                    |  v               |  ^
    *    /laptops/B ^  v           v                       v                  v  ^ /laptops/A
    *  /------------------\   /--------------\        /--------------\     /------------------\
    *  | intervalConsumer |   | echoProducer |        | echoProducer |     | intervalConsumer |
    *  \------------------/   \--------------/        \--------------/     \------------------/
    */

   // laptops have default routes toward the router
   topo.registerPrefix(laptopA, linkA->getFace(laptopA), "ndn:/");
   topo.registerPrefix(laptopB, linkB->getFace(laptopB), "ndn:/");

   // two laptops have same prefix in router FIB
   topo.registerPrefix(router, linkA->getFace(router), "ndn:/laptops");
   topo.registerPrefix(router, linkB->getFace(router), "ndn:/laptops");

   shared_ptr<TopologyAppLink> producerA = topo.addAppFace("pA", laptopA, "ndn:/laptops/A");
   topo.addEchoProducer(producerA->getClientFace());
   shared_ptr<TopologyAppLink> producerB = topo.addAppFace("pB", laptopB, "ndn:/laptops/B");
   topo.addEchoProducer(producerB->getClientFace());

   shared_ptr<TopologyAppLink> consumerAB = topo.addAppFace("cAB", laptopA);
   topo.addIntervalConsumer(consumerAB->getClientFace(), "ndn:/laptops/B",
                            time::milliseconds(100), 100);
   shared_ptr<TopologyAppLink> consumerBA = topo.addAppFace("cBA", laptopB);
   topo.addIntervalConsumer(consumerBA->getClientFace(), "ndn:/laptops/A",
                            time::milliseconds(100), 100);

   this->advanceClocks(time::milliseconds(5), time::seconds(12));

   // most Interests should be satisfied
   BOOST_CHECK_GE(consumerAB->getForwarderFace().getCounters().nOutData, 97);
   BOOST_CHECK_GE(consumerBA->getForwarderFace().getCounters().nOutData, 97);
 }

 BOOST_FIXTURE_TEST_CASE(PacketLoss, TwoLaptopsFixture)
 {
   /*
    *   test case Interests
    *           |
    *           v
    *      +--------+
    *      | router |
    *      +--------+
    *           |  v
    *      10ms |  v /laptops
    *           v
    *      +---------+
    *      | laptopA |
    *      +---------+
    *           ^  v
    *           |  v /laptops/A
    *           v
    *    /--------------\
    *    | echoProducer |
    *    \--------------/
    */

   // laptopA has prefix in router FIB; laptopB is unused in this test case
   topo.registerPrefix(router, linkA->getFace(router), "ndn:/laptops");

   shared_ptr<TopologyAppLink> producerA = topo.addAppFace("pA", laptopA, "ndn:/laptops/A");
   topo.addEchoProducer(producerA->getClientFace());

   shared_ptr<TopologyAppLink> consumer = topo.addAppFace("c", router);

   // Interest 1 completes normally
   shared_ptr<Interest> interest1 = makeInterest("ndn:/laptops/A/1");
   bool hasData1 = false;
   consumer->getClientFace().expressInterest(*interest1,
                                             bind([&hasData1] { hasData1 = true; }),
                                             nullptr, nullptr);
   this->advanceClocks(time::milliseconds(5), time::seconds(1));
   BOOST_CHECK_EQUAL(hasData1, true);

   // Interest 2 experiences a packet loss on initial transmission
   shared_ptr<Interest> interest2a = makeInterest("ndn:/laptops/A/2");
   bool hasData2a = false, hasTimeout2a = false;
   consumer->getClientFace().expressInterest(*interest2a,
                                             bind([&hasData2a] { hasData2a = true; }),
                                             nullptr,
                                             bind([&hasTimeout2a] { hasTimeout2a = true; }));
   producerA->fail();
   this->advanceClocks(time::milliseconds(5), time::milliseconds(60));
   BOOST_CHECK_EQUAL(hasData2a, false);
   BOOST_CHECK_EQUAL(hasTimeout2a, false);

   // Interest 2 retransmission is suppressed
   shared_ptr<Interest> interest2b = makeInterest("ndn:/laptops/A/2");
   bool hasData2b = false;
   consumer->getClientFace().expressInterest(*interest2b,
                                             bind([&hasData2b] { hasData2b = true; }),
                                             nullptr, nullptr);
   producerA->recover();
   this->advanceClocks(time::milliseconds(5), time::seconds(1));
   BOOST_CHECK_EQUAL(hasData2b, false);

   // Interest 2 retransmission gets through, and is answered
   shared_ptr<Interest> interest2c = makeInterest("ndn:/laptops/A/2");
   bool hasData2c = false;
   consumer->getClientFace().expressInterest(*interest2c,
                                             bind([&hasData2c] { hasData2c = true; }),
                                             nullptr, nullptr);
   this->advanceClocks(time::milliseconds(5), time::seconds(1));
   BOOST_CHECK_EQUAL(hasData2c, true);
 }

 BOOST_FIXTURE_TEST_CASE(Bug2831, TwoLaptopsFixture)
 {
   // make a two-node loop
   topo.registerPrefix(laptopA, linkA->getFace(laptopA), "ndn:/net");
   topo.registerPrefix(router, linkA->getFace(router), "ndn:/net");

   // send Interests from laptopA to router
   shared_ptr<TopologyAppLink> consumer = topo.addAppFace("c", laptopA);
   topo.addIntervalConsumer(consumer->getClientFace(), "ndn:/net",
                            time::milliseconds(100), 10);

   this->advanceClocks(time::milliseconds(5), time::seconds(2));

   // Interest shouldn't loop back from router
   BOOST_CHECK_EQUAL(linkA->getFace(router).getCounters().nOutInterests, 0);
 }

 BOOST_AUTO_TEST_SUITE_END() // TestAccessStrategy
 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/access-strategy.hpp"

	#include "tests/test-common.hpp"
	#include "topology-tester.hpp"

	namespace nfd {
	namespace fw {
	namespace tests {

	using namespace nfd::tests;

	// This test suite tests AccessStrategy's behavior as a black box,
	// without accessing its internals.
	//
	// Many test assertions are qualitative rather than quantitative.
	// They capture the design highlights of the strategy without requiring a definite value,
	// so that the test suite is not fragile to minor changes in the strategy implementation.
	//
	// Topology graphes in this test suite are shown in ASCII art,
	// in a style similar to ns-3 and ndnSIM examples.
	// They are enclosed in multi-line comments, which is an intentional violation of
	// code style rule 3.25. This is necessary because some lines ends with '\' which
	// would cause "multi-line comment" compiler warning if '//' comments are used.

	BOOST_AUTO_TEST_SUITE(Fw)
	BOOST_FIXTURE_TEST_SUITE(TestAccessStrategy, UnitTestTimeFixture)

	BOOST_AUTO_TEST_CASE(Registration)
	{
	BOOST_CHECK_EQUAL(Strategy::listRegistered().count(AccessStrategy::getStrategyName()), 1);
	}

	class TwoLaptopsFixture : public UnitTestTimeFixture
	{
	protected:
	TwoLaptopsFixture()
	{
	/*
	* +--------+
	* +----->\| router \|<------+
	* \| +--------+ \|
	* 10ms \| \| 20ms
	* v v
	* +---------+ +---------+
	* \| laptopA \| \| laptopB \|
	* +---------+ +---------+
	*/

	router = topo.addForwarder("R");
	laptopA = topo.addForwarder("A");
	laptopB = topo.addForwarder("B");

	topo.setStrategy<fw::AccessStrategy>(router);

	linkA = topo.addLink("RA", time::milliseconds(10), {router, laptopA});
	linkB = topo.addLink("RB", time::milliseconds(20), {router, laptopB});
	}

	protected:
	TopologyTester topo;

	TopologyNode router;
	TopologyNode laptopA;
	TopologyNode laptopB;
	shared_ptr<TopologyLink> linkA;
	shared_ptr<TopologyLink> linkB;
	};

	BOOST_FIXTURE_TEST_CASE(OneProducer, TwoLaptopsFixture)
	{
	/*
	* /------------------\
	* \| intervalConsumer \|
	* \------------------/
	* ^ v
	* \| v /laptops/A
	* \|
	* v
	* /laptops << +--------+ >> /laptops
	* +----->\| router \|<------+
	* \| +--------+ \|
	* 10ms \| \| 20ms
	* v v
	* +---------+ +---------+
	* \| laptopA \| \| laptopB \|
	* +---------+ +---------+
	* ^ v
	* \| v /laptops/A
	* v
	* /--------------\
	* \| echoProducer \|
	* \--------------/
	*/

	// two laptops have same prefix in router FIB
	topo.registerPrefix(router, linkA->getFace(router), "ndn:/laptops");
	topo.registerPrefix(router, linkB->getFace(router), "ndn:/laptops");

	shared_ptr<TopologyAppLink> producer = topo.addAppFace("p", laptopA, "ndn:/laptops/A");
	topo.addEchoProducer(producer->getClientFace());

	shared_ptr<TopologyAppLink> consumer = topo.addAppFace("c", router);
	topo.addIntervalConsumer(consumer->getClientFace(), "ndn:/laptops/A",
	time::milliseconds(100), 100);

	this->advanceClocks(time::milliseconds(5), time::seconds(12));

	// most Interests should be satisfied, and few Interests can go to wrong laptop
	BOOST_CHECK_GE(consumer->getForwarderFace().getCounters().nOutData, 97);
	BOOST_CHECK_GE(linkA->getFace(router).getCounters().nOutInterests, 97);
	BOOST_CHECK_LE(linkB->getFace(router).getCounters().nOutInterests, 5);
	}

	BOOST_FIXTURE_TEST_CASE(FastSlowProducer, TwoLaptopsFixture)
	{
	/*
	* /------------------\
	* \| intervalConsumer \|
	* \------------------/
	* ^ v
	* \| v /laptops/BOTH
	* \|
	* v
	* /laptops << +--------+ >> /laptops
	* +----->\| router \|<------+
	* \| +--------+ \|
	* 10ms \| \| 20ms
	* v v
	* +---------+ +---------+
	* \| laptopA \| \| laptopB \|
	* +---------+ +---------+
	* ^ v ^ v
	* \| v /laptops/BOTH \| v /laptops/BOTH
	* v v
	* /--------------\ /--------------\
	* \| echoProducer \| \| echoProducer \|
	* \--------------/ \--------------/
	*/

	// two laptops have same prefix in router FIB
	topo.registerPrefix(router, linkA->getFace(router), "ndn:/laptops");
	topo.registerPrefix(router, linkB->getFace(router), "ndn:/laptops");

	shared_ptr<TopologyAppLink> producerA = topo.addAppFace("pA", laptopA, "ndn:/laptops/BOTH");
	topo.addEchoProducer(producerA->getClientFace());
	shared_ptr<TopologyAppLink> producerB = topo.addAppFace("pB", laptopB, "ndn:/laptops/BOTH");
	topo.addEchoProducer(producerB->getClientFace());

	shared_ptr<TopologyAppLink> consumer = topo.addAppFace("c", router);
	topo.addIntervalConsumer(consumer->getClientFace(), "ndn:/laptops/BOTH",
	time::milliseconds(100), 100);

	this->advanceClocks(time::milliseconds(5), time::seconds(12));

	// most Interests should be satisfied, and few Interests can go to slower laptopB
	BOOST_CHECK_GE(consumer->getForwarderFace().getCounters().nOutData, 97);
	BOOST_CHECK_GE(linkA->getFace(router).getCounters().nOutInterests, 90);
	BOOST_CHECK_LE(linkB->getFace(router).getCounters().nOutInterests, 15);
	}

	BOOST_FIXTURE_TEST_CASE(ProducerMobility, TwoLaptopsFixture)
	{
	/*
	* /------------------\ /------------------\
	* \| intervalConsumer \| \| intervalConsumer \|
	* \------------------/ A \------------------/
	* ^ v f ^ v
	* \| v /laptops/M t \| v /laptops/M
	* \| e \|
	* v r v
	* /laptops << +--------+ >> /laptops /laptops << +--------+ >> /laptops
	* +----->\| router \|<------+ 6 +----->\| router \|<------+
	* \| +--------+ \| \| +--------+ \|
	* 10ms \| \| 20ms === s ==> 10ms \| \| 20ms
	* v v e v v
	* +---------+ +---------+ c +---------+ +---------+
	* \| laptopA \| \| laptopB \| o \| laptopA \| \| laptopB \|
	* +---------+ +---------+ n +---------+ +---------+
	* ^ v d v ^
	* \| v /laptops/M s /laptops/M v \|
	* v v
	* /--------------\ /--------------\
	* \| echoProducer \| \| echoProducer \|
	* \--------------/ \--------------/
	*/

	// two laptops have same prefix in router FIB
	topo.registerPrefix(router, linkA->getFace(router), "ndn:/laptops");
	topo.registerPrefix(router, linkB->getFace(router), "ndn:/laptops");

	shared_ptr<TopologyAppLink> producerA = topo.addAppFace("pA", laptopA, "ndn:/laptops/M");
	topo.addEchoProducer(producerA->getClientFace());
	shared_ptr<TopologyAppLink> producerB = topo.addAppFace("pB", laptopB, "ndn:/laptops/M");
	topo.addEchoProducer(producerB->getClientFace());

	shared_ptr<TopologyAppLink> consumer = topo.addAppFace("c", router);
	topo.addIntervalConsumer(consumer->getClientFace(), "ndn:/laptops/M",
	time::milliseconds(100), 100);

	// producer is initially on laptopA
	producerB->fail();
	this->advanceClocks(time::milliseconds(5), time::seconds(6));

	// few Interests can go to laptopB
	BOOST_CHECK_LE(linkB->getFace(router).getCounters().nOutInterests, 5);

	// producer moves to laptopB
	producerA->fail();
	producerB->recover();
	PacketCounter::rep nInterestsToA_beforeMove = linkA->getFace(router).getCounters().nOutInterests;
	this->advanceClocks(time::milliseconds(5), time::seconds(6));

	// few additional Interests can go to laptopA
	BOOST_CHECK_LE(linkA->getFace(router).getCounters().nOutInterests - nInterestsToA_beforeMove, 5);

	// most Interests should be satisfied
	BOOST_CHECK_GE(consumer->getForwarderFace().getCounters().nOutData, 97);
	}

	BOOST_FIXTURE_TEST_CASE(Bidirectional, TwoLaptopsFixture)
	{
	/*
	* /laptops << +--------+ >> /laptops
	* +----->\| router \|<------+
	* \| +--------+ \|
	* ^ 10ms \| \| 20ms ^
	* / ^ v v ^ /
	* +---------+ +---------+
	* +----->\| laptopA \| \| laptopB \|<------------+
	* \| +---------+ +---------+ \|
	* \| ^ v /laptops/A ^ v /laptops/B \|
	* ^ \| \| v \| v \| ^
	* /laptops/B ^ v v v v ^ /laptops/A
	* /------------------\ /--------------\ /--------------\ /------------------\
	* \| intervalConsumer \| \| echoProducer \| \| echoProducer \| \| intervalConsumer \|
	* \------------------/ \--------------/ \--------------/ \------------------/
	*/

	// laptops have default routes toward the router
	topo.registerPrefix(laptopA, linkA->getFace(laptopA), "ndn:/");
	topo.registerPrefix(laptopB, linkB->getFace(laptopB), "ndn:/");

	// two laptops have same prefix in router FIB
	topo.registerPrefix(router, linkA->getFace(router), "ndn:/laptops");
	topo.registerPrefix(router, linkB->getFace(router), "ndn:/laptops");

	shared_ptr<TopologyAppLink> producerA = topo.addAppFace("pA", laptopA, "ndn:/laptops/A");
	topo.addEchoProducer(producerA->getClientFace());
	shared_ptr<TopologyAppLink> producerB = topo.addAppFace("pB", laptopB, "ndn:/laptops/B");
	topo.addEchoProducer(producerB->getClientFace());

	shared_ptr<TopologyAppLink> consumerAB = topo.addAppFace("cAB", laptopA);
	topo.addIntervalConsumer(consumerAB->getClientFace(), "ndn:/laptops/B",
	time::milliseconds(100), 100);
	shared_ptr<TopologyAppLink> consumerBA = topo.addAppFace("cBA", laptopB);
	topo.addIntervalConsumer(consumerBA->getClientFace(), "ndn:/laptops/A",
	time::milliseconds(100), 100);

	this->advanceClocks(time::milliseconds(5), time::seconds(12));

	// most Interests should be satisfied
	BOOST_CHECK_GE(consumerAB->getForwarderFace().getCounters().nOutData, 97);
	BOOST_CHECK_GE(consumerBA->getForwarderFace().getCounters().nOutData, 97);
	}

	BOOST_FIXTURE_TEST_CASE(PacketLoss, TwoLaptopsFixture)
	{
	/*
	* test case Interests
	* \|
	* v
	* +--------+
	* \| router \|
	* +--------+
	* \| v
	* 10ms \| v /laptops
	* v
	* +---------+
	* \| laptopA \|
	* +---------+
	* ^ v
	* \| v /laptops/A
	* v
	* /--------------\
	* \| echoProducer \|
	* \--------------/
	*/

	// laptopA has prefix in router FIB; laptopB is unused in this test case
	topo.registerPrefix(router, linkA->getFace(router), "ndn:/laptops");

	shared_ptr<TopologyAppLink> producerA = topo.addAppFace("pA", laptopA, "ndn:/laptops/A");
	topo.addEchoProducer(producerA->getClientFace());

	shared_ptr<TopologyAppLink> consumer = topo.addAppFace("c", router);

	// Interest 1 completes normally
	shared_ptr<Interest> interest1 = makeInterest("ndn:/laptops/A/1");
	bool hasData1 = false;
	consumer->getClientFace().expressInterest(*interest1,
	bind([&hasData1] { hasData1 = true; }),
	nullptr, nullptr);
	this->advanceClocks(time::milliseconds(5), time::seconds(1));
	BOOST_CHECK_EQUAL(hasData1, true);

	// Interest 2 experiences a packet loss on initial transmission
	shared_ptr<Interest> interest2a = makeInterest("ndn:/laptops/A/2");
	bool hasData2a = false, hasTimeout2a = false;
	consumer->getClientFace().expressInterest(*interest2a,
	bind([&hasData2a] { hasData2a = true; }),
	nullptr,
	bind([&hasTimeout2a] { hasTimeout2a = true; }));
	producerA->fail();
	this->advanceClocks(time::milliseconds(5), time::milliseconds(60));
	BOOST_CHECK_EQUAL(hasData2a, false);
	BOOST_CHECK_EQUAL(hasTimeout2a, false);

	// Interest 2 retransmission is suppressed
	shared_ptr<Interest> interest2b = makeInterest("ndn:/laptops/A/2");
	bool hasData2b = false;
	consumer->getClientFace().expressInterest(*interest2b,
	bind([&hasData2b] { hasData2b = true; }),
	nullptr, nullptr);
	producerA->recover();
	this->advanceClocks(time::milliseconds(5), time::seconds(1));
	BOOST_CHECK_EQUAL(hasData2b, false);

	// Interest 2 retransmission gets through, and is answered
	shared_ptr<Interest> interest2c = makeInterest("ndn:/laptops/A/2");
	bool hasData2c = false;
	consumer->getClientFace().expressInterest(*interest2c,
	bind([&hasData2c] { hasData2c = true; }),
	nullptr, nullptr);
	this->advanceClocks(time::milliseconds(5), time::seconds(1));
	BOOST_CHECK_EQUAL(hasData2c, true);
	}

	BOOST_FIXTURE_TEST_CASE(Bug2831, TwoLaptopsFixture)
	{
	// make a two-node loop
	topo.registerPrefix(laptopA, linkA->getFace(laptopA), "ndn:/net");
	topo.registerPrefix(router, linkA->getFace(router), "ndn:/net");

	// send Interests from laptopA to router
	shared_ptr<TopologyAppLink> consumer = topo.addAppFace("c", laptopA);
	topo.addIntervalConsumer(consumer->getClientFace(), "ndn:/net",
	time::milliseconds(100), 10);

	this->advanceClocks(time::milliseconds(5), time::seconds(2));

	// Interest shouldn't loop back from router
	BOOST_CHECK_EQUAL(linkA->getFace(router).getCounters().nOutInterests, 0);
	}

	BOOST_AUTO_TEST_SUITE_END() // TestAccessStrategy
	BOOST_AUTO_TEST_SUITE_END() // Fw

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