diff --git a/libs/ardour/ardour/audioengine.h b/libs/ardour/ardour/audioengine.h
index 99b2508d8c..7b4ba2d15d 100644
--- a/libs/ardour/ardour/audioengine.h
+++ b/libs/ardour/ardour/audioengine.h
@@ -64,7 +64,7 @@ class ProcessThread;
 class AudioEngine : public SessionHandlePtr
 {
 public:
-	typedef std::set<boost::shared_ptr<Port> > Ports;
+	typedef std::map<std::string,boost::shared_ptr<Port> > Ports;
 
 	AudioEngine (std::string client_name, std::string session_uuid);
 	virtual ~AudioEngine ();
@@ -185,6 +185,7 @@ public:
 	void get_physical_inputs (DataType type, std::vector<std::string>&);
 
 	boost::shared_ptr<Port> get_port_by_name (const std::string &);
+	void port_renamed (const std::string&, const std::string&);
 
 	enum TransportState {
 		TransportStopped = JackTransportStopped,
diff --git a/libs/ardour/audioengine.cc b/libs/ardour/audioengine.cc
index 215bb296a9..69155f54b3 100644
--- a/libs/ardour/audioengine.cc
+++ b/libs/ardour/audioengine.cc
@@ -383,10 +383,10 @@ AudioEngine::_connect_callback (jack_port_id_t id_a, jack_port_id_t id_b, int co
 	boost::shared_ptr<Ports> pr = ae->ports.reader ();
 	Ports::iterator i = pr->begin ();
 	while (i != pr->end() && (port_a == 0 || port_b == 0)) {
-		if (jack_port_a == (*i)->jack_port()) {
-			port_a = *i;
-		} else if (jack_port_b == (*i)->jack_port()) {
-			port_b = *i;
+		if (jack_port_a == i->second->jack_port()) {
+			port_a = i->second;
+		} else if (jack_port_b == i->second->jack_port()) {
+			port_b = i->second;
 		}
 		++i;
 	}
@@ -410,7 +410,7 @@ AudioEngine::split_cycle (pframes_t offset)
 	boost::shared_ptr<Ports> p = ports.reader();
 
 	for (Ports::iterator i = p->begin(); i != p->end(); ++i) {
-		(*i)->cycle_split ();
+		i->second->cycle_split ();
 	}
 }
 
@@ -488,7 +488,7 @@ AudioEngine::process_callback (pframes_t nframes)
 	boost::shared_ptr<Ports> p = ports.reader();
 
 	for (Ports::iterator i = p->begin(); i != p->end(); ++i) {
-		(*i)->cycle_start (nframes);
+		i->second->cycle_start (nframes);
 	}
 
 	/* test if we are freewheeling and there are freewheel signals connected.
@@ -526,12 +526,12 @@ AudioEngine::process_callback (pframes_t nframes)
 
 			bool x;
 
-			if ((*i)->last_monitor() != (x = (*i)->jack_monitoring_input ())) {
-				(*i)->set_last_monitor (x);
+			if (i->second->last_monitor() != (x = i->second->jack_monitoring_input ())) {
+				i->second->set_last_monitor (x);
 				/* XXX I think this is dangerous, due to
 				   a likely mutex in the signal handlers ...
 				*/
-				(*i)->MonitorInputChanged (x); /* EMIT SIGNAL */
+				i->second->MonitorInputChanged (x); /* EMIT SIGNAL */
 			}
 		}
 		last_monitor_check = next_processed_frames;
@@ -543,8 +543,8 @@ AudioEngine::process_callback (pframes_t nframes)
 
 		for (Ports::iterator i = p->begin(); i != p->end(); ++i) {
 
-			if ((*i)->sends_output()) {
-				(*i)->get_buffer(nframes).silence(nframes);
+			if (i->second->sends_output()) {
+				i->second->get_buffer(nframes).silence(nframes);
 			}
 		}
 	}
@@ -552,7 +552,7 @@ AudioEngine::process_callback (pframes_t nframes)
 	// Finalize ports
 
 	for (Ports::iterator i = p->begin(); i != p->end(); ++i) {
-		(*i)->cycle_end (nframes);
+		i->second->cycle_end (nframes);
 	}
 
 	_processed_frames = next_processed_frames;
@@ -643,7 +643,7 @@ AudioEngine::jack_bufsize_callback (pframes_t nframes)
 		boost::shared_ptr<Ports> p = ports.reader();
 
 		for (Ports::iterator i = p->begin(); i != p->end(); ++i) {
-			(*i)->reset();
+			i->second->reset();
 		}
 	}
 
@@ -708,7 +708,7 @@ AudioEngine::set_session (Session *s)
 		boost::shared_ptr<Ports> p = ports.reader();
 
 		for (Ports::iterator i = p->begin(); i != p->end(); ++i) {
-			(*i)->cycle_start (blocksize);
+			i->second->cycle_start (blocksize);
 		}
 
 		_session->process (blocksize);
@@ -721,7 +721,7 @@ AudioEngine::set_session (Session *s)
 		_session->process (blocksize);
 
 		for (Ports::iterator i = p->begin(); i != p->end(); ++i) {
-			(*i)->cycle_end (blocksize);
+			i->second->cycle_end (blocksize);
 		}
 	}
 }
@@ -784,7 +784,7 @@ AudioEngine::register_port (DataType dtype, const string& portname, bool input)
 
 		RCUWriter<Ports> writer (ports);
 		boost::shared_ptr<Ports> ps = writer.get_copy ();
-		ps->insert (ps->begin(), newport);
+		ps->insert (make_pair (make_port_name_relative (portname), newport));
 
 		/* writer goes out of scope, forces update */
 
@@ -828,7 +828,11 @@ AudioEngine::unregister_port (boost::shared_ptr<Port> port)
 	{
 		RCUWriter<Ports> writer (ports);
 		boost::shared_ptr<Ports> ps = writer.get_copy ();
-		ps->erase (port);
+		Ports::iterator x = ps->find (make_port_name_relative (port->name()));
+
+		if (x != ps->end()) {
+			ps->erase (x);
+		}
 
 		/* writer goes out of scope, forces update */
 	}
@@ -977,19 +981,40 @@ AudioEngine::get_port_by_name (const string& portname)
                 return boost::shared_ptr<Port> ();
         }
 
-	std::string const rel = make_port_name_relative (portname);
-
 	boost::shared_ptr<Ports> pr = ports.reader();
+	std::string rel = make_port_name_relative (portname);
+	Ports::iterator x = pr->find (rel);
 
-	for (Ports::iterator i = pr->begin(); i != pr->end(); ++i) {
-		if (rel == (*i)->name()) {
-			return *i;
+	if (x != pr->end()) {
+		/* its possible that the port was renamed by some 3rd party and
+		   we don't know about it. check for this (the check is quick
+		   and cheap), and if so, rename the port (which will alter
+		   the port map as a side effect).
+		*/
+		const std::string check = make_port_name_relative (jack_port_name (x->second->jack_port()));
+		if (check != rel) {
+			x->second->set_name (check);
 		}
+		return x->second;
 	}
 
         return boost::shared_ptr<Port> ();
 }
 
+void
+AudioEngine::port_renamed (const std::string& old_relative_name, const std::string& new_relative_name)
+{
+	RCUWriter<Ports> writer (ports);
+	boost::shared_ptr<Ports> p = writer.get_copy();
+	Ports::iterator x = p->find (old_relative_name);
+	
+	if (x != p->end()) {
+		boost::shared_ptr<Port> port = x->second;
+		p->erase (x);
+		p->insert (make_pair (new_relative_name, port));
+	}
+}
+
 const char **
 AudioEngine::get_ports (const string& port_name_pattern, const string& type_name_pattern, uint32_t flags)
 {
@@ -1329,7 +1354,7 @@ AudioEngine::reconnect_to_jack ()
 	boost::shared_ptr<Ports> p = ports.reader ();
 
 	for (i = p->begin(); i != p->end(); ++i) {
-		if ((*i)->reestablish ()) {
+		if (i->second->reestablish ()) {
 			break;
 		}
 	}
@@ -1364,7 +1389,7 @@ AudioEngine::reconnect_to_jack ()
 	/* re-establish connections */
 
 	for (i = p->begin(); i != p->end(); ++i) {
-		(*i)->reconnect ();
+		i->second->reconnect ();
 	}
 
 	MIDI::Manager::instance()->reconnect ();
diff --git a/libs/ardour/port.cc b/libs/ardour/port.cc
index 45874bba8d..157b7e9a21 100644
--- a/libs/ardour/port.cc
+++ b/libs/ardour/port.cc
@@ -472,9 +472,11 @@ Port::set_name (std::string const & n)
 	int const r = jack_port_set_name (_jack_port, n.c_str());
 
 	if (r == 0) {
+		_engine->port_renamed (_name, n);
 		_name = n;
 	}
 
+
 	return r;
 }