diff --git a/ndn-cxx/face.cpp b/ndn-cxx/face.cpp
index 53ed411..32aa630 100644
--- a/ndn-cxx/face.cpp
+++ b/ndn-cxx/face.cpp
@@ -24,7 +24,6 @@
 #include "ndn-cxx/impl/face-impl.hpp"
 #include "ndn-cxx/net/face-uri.hpp"
 #include "ndn-cxx/security/signing-helpers.hpp"
-#include "ndn-cxx/util/random.hpp"
 #include "ndn-cxx/util/time.hpp"
 
 // NDN_LOG_INIT(ndn.Face) is declared in face-impl.hpp
@@ -59,7 +58,6 @@
   : m_internalIoService(make_unique<boost::asio::io_service>())
   , m_ioService(*m_internalIoService)
   , m_internalKeyChain(make_unique<KeyChain>())
-  , m_impl(make_shared<Impl>(*this))
 {
   construct(std::move(transport), *m_internalKeyChain);
 }
@@ -67,7 +65,6 @@
 Face::Face(boost::asio::io_service& ioService)
   : m_ioService(ioService)
   , m_internalKeyChain(make_unique<KeyChain>())
-  , m_impl(make_shared<Impl>(*this))
 {
   construct(nullptr, *m_internalKeyChain);
 }
@@ -76,7 +73,6 @@
   : m_internalIoService(make_unique<boost::asio::io_service>())
   , m_ioService(*m_internalIoService)
   , m_internalKeyChain(make_unique<KeyChain>())
-  , m_impl(make_shared<Impl>(*this))
 {
   construct(make_shared<TcpTransport>(host, port), *m_internalKeyChain);
 }
@@ -84,7 +80,6 @@
 Face::Face(shared_ptr<Transport> transport, KeyChain& keyChain)
   : m_internalIoService(make_unique<boost::asio::io_service>())
   , m_ioService(*m_internalIoService)
-  , m_impl(make_shared<Impl>(*this))
 {
   construct(std::move(transport), keyChain);
 }
@@ -92,14 +87,12 @@
 Face::Face(shared_ptr<Transport> transport, boost::asio::io_service& ioService)
   : m_ioService(ioService)
   , m_internalKeyChain(make_unique<KeyChain>())
-  , m_impl(make_shared<Impl>(*this))
 {
   construct(std::move(transport), *m_internalKeyChain);
 }
 
 Face::Face(shared_ptr<Transport> transport, boost::asio::io_service& ioService, KeyChain& keyChain)
   : m_ioService(ioService)
-  , m_impl(make_shared<Impl>(*this))
 {
   construct(std::move(transport), keyChain);
 }
@@ -152,14 +145,15 @@
 void
 Face::construct(shared_ptr<Transport> transport, KeyChain& keyChain)
 {
+  BOOST_ASSERT(m_impl == nullptr);
+  m_impl = make_shared<Impl>(*this, keyChain);
+
   if (transport == nullptr) {
     transport = makeDefaultTransport();
+    BOOST_ASSERT(transport != nullptr);
   }
-  BOOST_ASSERT(transport != nullptr);
   m_transport = std::move(transport);
 
-  m_nfdController = make_unique<nfd::Controller>(*this, keyChain);
-
   IO_CAPTURE_WEAK_IMPL(post) {
     impl->ensureConnected(false);
   } IO_CAPTURE_WEAK_IMPL_END
@@ -167,12 +161,6 @@
 
 Face::~Face() = default;
 
-shared_ptr<Transport>
-Face::getTransport()
-{
-  return m_transport;
-}
-
 PendingInterestHandle
 Face::expressInterest(const Interest& interest,
                       const DataCallback& afterSatisfied,
@@ -326,9 +314,7 @@
     m_ioService.run();
   }
   catch (...) {
-    m_impl->m_ioServiceWork.reset();
-    m_impl->m_pendingInterestTable.clear();
-    m_impl->m_registeredPrefixTable.clear();
+    m_impl->shutdown();
     throw;
   }
 }
@@ -337,13 +323,9 @@
 Face::shutdown()
 {
   IO_CAPTURE_WEAK_IMPL(post) {
-    impl->m_pendingInterestTable.clear();
-    impl->m_registeredPrefixTable.clear();
-
+    impl->shutdown();
     if (m_transport->isConnected())
       m_transport->close();
-
-    impl->m_ioServiceWork.reset();
   } IO_CAPTURE_WEAK_IMPL_END
 }
 
diff --git a/ndn-cxx/face.hpp b/ndn-cxx/face.hpp
index 6ee8949..f1b32a9 100644
--- a/ndn-cxx/face.hpp
+++ b/ndn-cxx/face.hpp
@@ -43,10 +43,6 @@
 class InterestFilterId;
 class InterestFilterHandle;
 
-namespace nfd {
-class Controller;
-} // namespace nfd
-
 /**
  * @brief Callback invoked when expressed Interest gets satisfied with a Data packet
  */
@@ -461,7 +457,7 @@
   shutdown();
 
   /**
-   * @return reference to io_service object
+   * @brief Returns a reference to the io_service used by this face.
    */
   boost::asio::io_service&
   getIoService()
@@ -471,10 +467,13 @@
 
 NDN_CXX_PUBLIC_WITH_TESTS_ELSE_PROTECTED:
   /**
-   * @return underlying transport
+   * @brief Returns the underlying transport.
    */
   shared_ptr<Transport>
-  getTransport();
+  getTransport() const
+  {
+    return m_transport;
+  }
 
 protected:
   virtual void
@@ -509,7 +508,7 @@
                        const UnregisterPrefixFailureCallback& onFailure);
 
 private:
-  /// the io_service owned by this Face, could be null
+  /// the io_service owned by this Face, may be null
   unique_ptr<boost::asio::io_service> m_internalIoService;
   /// the io_service used by this Face
   boost::asio::io_service& m_ioService;
@@ -517,16 +516,14 @@
   shared_ptr<Transport> m_transport;
 
   /**
-   * @brief if not null, a pointer to an internal KeyChain owned by Face
-   * @note if a KeyChain is supplied to constructor, this pointer will be null,
-   *       and the passed KeyChain is given to nfdController;
-   *       currently Face does not keep the KeyChain passed in constructor
-   *       because it's not needed, but this may change in the future
+   * @brief If not null, a pointer to an internal KeyChain owned by this Face.
+   * @note If a KeyChain is supplied to constructor, this pointer will be null,
+   *       and the supplied KeyChain is passed to Face::Impl constructor;
+   *       currently Face does not keep a ref to the provided KeyChain
+   *       because it's not needed, but this may change in the future.
    */
   unique_ptr<KeyChain> m_internalKeyChain;
 
-  unique_ptr<nfd::Controller> m_nfdController;
-
   class Impl;
   shared_ptr<Impl> m_impl;
 
diff --git a/ndn-cxx/impl/face-impl.hpp b/ndn-cxx/impl/face-impl.hpp
index 4a9c56a..2e98467 100644
--- a/ndn-cxx/impl/face-impl.hpp
+++ b/ndn-cxx/impl/face-impl.hpp
@@ -43,8 +43,8 @@
 // DEBUG level: packet logging.
 // Each log entry starts with a direction symbol ('<' denotes an outgoing packet, '>' denotes an
 // incoming packet) and a packet type symbol ('I' denotes an Interest, 'D' denotes a Data, 'N'
-// denotes a Nack). Interest is printed as its string representation, Data is printed as name only,
-// Nack is printed as the Interest followed by the Nack reason and delimited by a '~' symbol. A
+// denotes a Nack). Interest is printed in its URI string representation, Data is printed as name
+// only, Nack is printed as the Interest followed by the Nack reason separated by a '~' symbol. A
 // log line about an incoming packet may be followed by zero or more lines about Interest matching
 // InterestFilter, Data satisfying Interest, or Nack rejecting Interest, which are also written at
 // DEBUG level.
@@ -62,10 +62,10 @@
   using InterestFilterTable = RecordContainer<InterestFilterRecord>;
   using RegisteredPrefixTable = RecordContainer<RegisteredPrefix>;
 
-  explicit
-  Impl(Face& face)
+  Impl(Face& face, KeyChain& keyChain)
     : m_face(face)
     , m_scheduler(m_face.getIoService())
+    , m_nfdController(m_face, keyChain)
   {
     auto postOnEmptyPitOrNoRegisteredPrefixes = [this] {
       this->m_face.getIoService().post([this] { this->onEmptyPitOrNoRegisteredPrefixes(); });
@@ -137,6 +137,7 @@
 
       return true;
     });
+
     // if Data matches no pending Interest record, it is sent to the forwarder as unsolicited Data
     return hasForwarderMatch || !hasAppMatch;
   }
@@ -166,6 +167,7 @@
       }
       return true;
     });
+
     // send "least severe" Nack from any PendingInterest record originated from forwarder, because
     // it is unimportant to consider Nack reason for the unlikely case when forwarder sends multiple
     // Interests to an app in a short while
@@ -262,7 +264,7 @@
     NDN_LOG_INFO("registering prefix: " << prefix);
     auto id = m_registeredPrefixTable.allocateId();
 
-    m_face.m_nfdController->start<nfd::RibRegisterCommand>(
+    m_nfdController.start<nfd::RibRegisterCommand>(
       nfd::ControlParameters().setName(prefix).setFlags(flags),
       [=] (const nfd::ControlParameters&) {
         NDN_LOG_INFO("registered prefix: " << prefix);
@@ -307,7 +309,8 @@
     }
 
     NDN_LOG_INFO("unregistering prefix: " << record->getPrefix());
-    m_face.m_nfdController->start<nfd::RibUnregisterCommand>(
+
+    m_nfdController.start<nfd::RibUnregisterCommand>(
       nfd::ControlParameters().setName(record->getPrefix()),
       [=] (const nfd::ControlParameters&) {
         NDN_LOG_INFO("unregistered prefix: " << record->getPrefix());
@@ -328,9 +331,10 @@
   void
   ensureConnected(bool wantResume)
   {
-    if (!m_face.m_transport->isConnected())
-      m_face.m_transport->connect(m_face.m_ioService,
-                                  [=] (const Block& wire) { m_face.onReceiveElement(wire); });
+    if (!m_face.m_transport->isConnected()) {
+      m_face.m_transport->connect(m_face.getIoService(),
+                                  [this] (const Block& wire) { m_face.onReceiveElement(wire); });
+    }
 
     if (wantResume && !m_face.m_transport->isReceiving()) {
       m_face.m_transport->resume();
@@ -348,6 +352,14 @@
     }
   }
 
+  void
+  shutdown()
+  {
+    m_ioServiceWork.reset();
+    m_pendingInterestTable.clear();
+    m_registeredPrefixTable.clear();
+  }
+
 private:
   /** @brief Finish packet encoding
    *  @param lpPacket NDNLP packet without FragmentField
@@ -376,6 +388,7 @@
   Face& m_face;
   Scheduler m_scheduler;
   scheduler::ScopedEventId m_processEventsTimeoutEvent;
+  nfd::Controller m_nfdController;
 
   PendingInterestTable m_pendingInterestTable;
   InterestFilterTable m_interestFilterTable;
diff --git a/ndn-cxx/transport/detail/stream-transport-impl.hpp b/ndn-cxx/transport/detail/stream-transport-impl.hpp
index a90143a..97b796e 100644
--- a/ndn-cxx/transport/detail/stream-transport-impl.hpp
+++ b/ndn-cxx/transport/detail/stream-transport-impl.hpp
@@ -41,15 +41,13 @@
 class StreamTransportImpl : public std::enable_shared_from_this<StreamTransportImpl<BaseTransport, Protocol>>
 {
 public:
-  typedef StreamTransportImpl<BaseTransport, Protocol> Impl;
-  typedef std::list<Block> BlockSequence;
-  typedef std::list<BlockSequence> TransmissionQueue;
+  using Impl = StreamTransportImpl<BaseTransport, Protocol>;
+  using BlockSequence = std::list<Block>;
+  using TransmissionQueue = std::list<BlockSequence>;
 
   StreamTransportImpl(BaseTransport& transport, boost::asio::io_service& ioService)
     : m_transport(transport)
     , m_socket(ioService)
-    , m_inputBufferSize(0)
-    , m_isConnecting(false)
     , m_connectTimer(ioService)
   {
   }
@@ -57,21 +55,22 @@
   void
   connect(const typename Protocol::endpoint& endpoint)
   {
-    if (!m_isConnecting) {
-      m_isConnecting = true;
-
-      // Wait at most 4 seconds to connect
-      /// @todo Decide whether this number should be configurable
-      m_connectTimer.expires_from_now(std::chrono::seconds(4));
-      m_connectTimer.async_wait([self = this->shared_from_this()] (const auto& error) {
-        self->connectTimeoutHandler(error);
-      });
-
-      m_socket.open();
-      m_socket.async_connect(endpoint, [self = this->shared_from_this()] (const auto& error) {
-        self->connectHandler(error);
-      });
+    if (m_isConnecting) {
+      return;
     }
+    m_isConnecting = true;
+
+    // Wait at most 4 seconds to connect
+    /// @todo Decide whether this number should be configurable
+    m_connectTimer.expires_from_now(std::chrono::seconds(4));
+    m_connectTimer.async_wait([self = this->shared_from_this()] (const auto& error) {
+      self->connectTimeoutHandler(error);
+    });
+
+    m_socket.open();
+    m_socket.async_connect(endpoint, [self = this->shared_from_this()] (const auto& error) {
+      self->connectHandler(error);
+    });
   }
 
   void
@@ -138,19 +137,18 @@
     m_isConnecting = false;
     m_connectTimer.cancel();
 
-    if (!error) {
-      m_transport.m_isConnected = true;
-
-      if (!m_transmissionQueue.empty()) {
-        resume();
-        asyncWrite();
-      }
-    }
-    else {
+    if (error) {
       m_transport.m_isConnected = false;
       m_transport.close();
       NDN_THROW(Transport::Error(error, "error while connecting to the forwarder"));
     }
+
+    m_transport.m_isConnected = true;
+
+    if (!m_transmissionQueue.empty()) {
+      resume();
+      asyncWrite();
+    }
   }
 
   void
@@ -181,7 +179,8 @@
   {
     BOOST_ASSERT(!m_transmissionQueue.empty());
     boost::asio::async_write(m_socket, m_transmissionQueue.front(),
-      bind(&Impl::handleAsyncWrite, this->shared_from_this(), _1, m_transmissionQueue.begin()));
+                             bind(&Impl::handleAsyncWrite, this->shared_from_this(), _1,
+                                  m_transmissionQueue.begin()));
   }
 
   void
@@ -192,9 +191,8 @@
         // async receive has been explicitly cancelled (e.g., socket close)
         return;
       }
-
       m_transport.close();
-      NDN_THROW(Transport::Error(error, "error while sending data to socket"));
+      NDN_THROW(Transport::Error(error, "error while writing data to socket"));
     }
 
     if (!m_transport.m_isConnected) {
@@ -224,7 +222,6 @@
         // async receive has been explicitly cancelled (e.g., socket close)
         return;
       }
-
       m_transport.close();
       NDN_THROW(Transport::Error(error, "error while receiving data from socket"));
     }
@@ -236,8 +233,7 @@
     bool hasProcessedSome = processAllReceived(m_inputBuffer, offset, m_inputBufferSize);
     if (!hasProcessedSome && m_inputBufferSize == MAX_NDN_PACKET_SIZE && offset == 0) {
       m_transport.close();
-      NDN_THROW(Transport::Error(boost::system::error_code(),
-                                 "input buffer full, but a valid TLV cannot be decoded"));
+      NDN_THROW(Transport::Error("input buffer full, but a valid TLV cannot be decoded"));
     }
 
     if (offset > 0) {
@@ -263,7 +259,7 @@
       if (!isOk)
         return false;
 
-      m_transport.receive(element);
+      m_transport.m_receiveCallback(element);
       offset += element.size();
     }
     return true;
@@ -274,12 +270,11 @@
 
   typename Protocol::socket m_socket;
   uint8_t m_inputBuffer[MAX_NDN_PACKET_SIZE];
-  size_t m_inputBufferSize;
+  size_t m_inputBufferSize = 0;
 
   TransmissionQueue m_transmissionQueue;
-  bool m_isConnecting;
-
   boost::asio::steady_timer m_connectTimer;
+  bool m_isConnecting = false;
 };
 
 } // namespace detail
diff --git a/ndn-cxx/transport/tcp-transport.cpp b/ndn-cxx/transport/tcp-transport.cpp
index 0b78b19..512f5e1 100644
--- a/ndn-cxx/transport/tcp-transport.cpp
+++ b/ndn-cxx/transport/tcp-transport.cpp
@@ -78,15 +78,13 @@
 }
 
 void
-TcpTransport::connect(boost::asio::io_service& ioService,
-                      const ReceiveCallback& receiveCallback)
+TcpTransport::connect(boost::asio::io_service& ioService, ReceiveCallback receiveCallback)
 {
   NDN_LOG_DEBUG("connect host=" << m_host << " port=" << m_port);
 
   if (m_impl == nullptr) {
-    Transport::connect(ioService, receiveCallback);
-
-    m_impl = make_shared<Impl>(ref(*this), ref(ioService));
+    Transport::connect(ioService, std::move(receiveCallback));
+    m_impl = make_shared<Impl>(*this, ioService);
   }
 
   boost::asio::ip::tcp::resolver::query query(m_host, m_port);
diff --git a/ndn-cxx/transport/tcp-transport.hpp b/ndn-cxx/transport/tcp-transport.hpp
index e3bb5a3..a727f27 100644
--- a/ndn-cxx/transport/tcp-transport.hpp
+++ b/ndn-cxx/transport/tcp-transport.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2018 Regents of the University of California.
+ * Copyright (c) 2013-2019 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -50,7 +50,7 @@
   ~TcpTransport() override;
 
   void
-  connect(boost::asio::io_service& ioService, const ReceiveCallback& receiveCallback) override;
+  connect(boost::asio::io_service& ioService, ReceiveCallback receiveCallback) override;
 
   void
   close() override;
diff --git a/ndn-cxx/transport/transport.cpp b/ndn-cxx/transport/transport.cpp
index 23895b0..a78e36f 100644
--- a/ndn-cxx/transport/transport.cpp
+++ b/ndn-cxx/transport/transport.cpp
@@ -24,25 +24,17 @@
 namespace ndn {
 
 Transport::Error::Error(const boost::system::error_code& code, const std::string& msg)
-  : std::runtime_error(msg + (code.value() ? " (" + code.category().message(code.value()) + ")" : ""))
-{
-}
-
-Transport::Transport()
-  : m_ioService(nullptr)
-  , m_isConnected(false)
-  , m_isReceiving(false)
+  : std::runtime_error(msg + (code.value() ? " (" + code.message() + ")" : ""))
 {
 }
 
 void
-Transport::connect(boost::asio::io_service& ioService,
-                   const ReceiveCallback& receiveCallback)
+Transport::connect(boost::asio::io_service& ioService, ReceiveCallback receiveCallback)
 {
   BOOST_ASSERT(receiveCallback != nullptr);
 
   m_ioService = &ioService;
-  m_receiveCallback = receiveCallback;
+  m_receiveCallback = std::move(receiveCallback);
 }
 
 } // namespace ndn
diff --git a/ndn-cxx/transport/transport.hpp b/ndn-cxx/transport/transport.hpp
index 6954686..4f4d72b 100644
--- a/ndn-cxx/transport/transport.hpp
+++ b/ndn-cxx/transport/transport.hpp
@@ -30,7 +30,7 @@
 
 namespace ndn {
 
-/** \brief provides TLV-block delivery service
+/** \brief Provides TLV-block delivery service.
  */
 class Transport : noncopyable
 {
@@ -43,21 +43,19 @@
     Error(const boost::system::error_code& code, const std::string& msg);
   };
 
-  typedef function<void(const Block& wire)> ReceiveCallback;
-  typedef function<void()> ErrorCallback;
-
-  Transport();
+  using ReceiveCallback = std::function<void(const Block& wire)>;
+  using ErrorCallback = std::function<void()>;
 
   virtual
   ~Transport() = default;
 
-  /** \brief asynchronously open the connection
+  /** \brief Asynchronously open the connection.
    *  \param ioService io_service to create socket on
    *  \param receiveCallback callback function when a TLV block is received; must not be empty
    *  \throw boost::system::system_error connection cannot be established
    */
   virtual void
-  connect(boost::asio::io_service& ioService, const ReceiveCallback& receiveCallback);
+  connect(boost::asio::io_service& ioService, ReceiveCallback receiveCallback);
 
   /** \brief Close the connection.
    */
@@ -78,7 +76,7 @@
   send(const Block& header, const Block& payload) = 0;
 
   /** \brief pause the transport
-   *  \post receiveCallback will not be invoked
+   *  \post the receive callback will not be invoked
    *  \note This operation has no effect if transport has been paused,
    *        or when connection is being established.
    */
@@ -86,7 +84,7 @@
   pause() = 0;
 
   /** \brief resume the transport
-   *  \post receiveCallback will be invoked
+   *  \post the receive callback will be invoked
    *  \note This operation has no effect if transport is not paused,
    *        or when connection is being established.
    */
@@ -97,45 +95,27 @@
    *  \retval false connection is not yet established or has been closed
    */
   bool
-  isConnected() const;
+  isConnected() const noexcept
+  {
+    return m_isConnected;
+  }
 
-  /** \retval true incoming packets are expected, receiveCallback will be invoked
-   *  \retval false incoming packets are not expected, receiveCallback will not be invoked
+  /** \retval true incoming packets are expected, the receive callback will be invoked
+   *  \retval false incoming packets are not expected, the receive callback will not be invoked
    */
   bool
-  isReceiving() const;
+  isReceiving() const noexcept
+  {
+    return m_isReceiving;
+  }
 
 protected:
-  /** \brief invoke the receive callback
-   */
-  void
-  receive(const Block& wire);
-
-protected:
-  boost::asio::io_service* m_ioService;
-  bool m_isConnected;
-  bool m_isReceiving;
+  boost::asio::io_service* m_ioService = nullptr;
   ReceiveCallback m_receiveCallback;
+  bool m_isConnected = false;
+  bool m_isReceiving = false;
 };
 
-inline bool
-Transport::isConnected() const
-{
-  return m_isConnected;
-}
-
-inline bool
-Transport::isReceiving() const
-{
-  return m_isReceiving;
-}
-
-inline void
-Transport::receive(const Block& wire)
-{
-  m_receiveCallback(wire);
-}
-
 } // namespace ndn
 
 #endif // NDN_TRANSPORT_TRANSPORT_HPP
diff --git a/ndn-cxx/transport/unix-transport.cpp b/ndn-cxx/transport/unix-transport.cpp
index b33704c..6e909a2 100644
--- a/ndn-cxx/transport/unix-transport.cpp
+++ b/ndn-cxx/transport/unix-transport.cpp
@@ -73,15 +73,13 @@
 }
 
 void
-UnixTransport::connect(boost::asio::io_service& ioService,
-                       const ReceiveCallback& receiveCallback)
+UnixTransport::connect(boost::asio::io_service& ioService, ReceiveCallback receiveCallback)
 {
   NDN_LOG_DEBUG("connect path=" << m_unixSocket);
 
   if (m_impl == nullptr) {
-    Transport::connect(ioService, receiveCallback);
-
-    m_impl = make_shared<Impl>(ref(*this), ref(ioService));
+    Transport::connect(ioService, std::move(receiveCallback));
+    m_impl = make_shared<Impl>(*this, ioService);
   }
 
   m_impl->connect(boost::asio::local::stream_protocol::endpoint(m_unixSocket));
diff --git a/ndn-cxx/transport/unix-transport.hpp b/ndn-cxx/transport/unix-transport.hpp
index 424ed53..d18dbe4 100644
--- a/ndn-cxx/transport/unix-transport.hpp
+++ b/ndn-cxx/transport/unix-transport.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2018 Regents of the University of California.
+ * Copyright (c) 2013-2019 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -47,8 +47,7 @@
   ~UnixTransport() override;
 
   void
-  connect(boost::asio::io_service& ioService,
-          const ReceiveCallback& receiveCallback) override;
+  connect(boost::asio::io_service& ioService, ReceiveCallback receiveCallback) override;
 
   void
   close() override;