diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index c9d2de4d07..9f8102c928 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -186,6 +186,12 @@ class LIBARDOUR_API Session : public PBD::StatefulDestructible, public PBD::Scop
 	static int get_info_from_path (const std::string& xmlpath, float& sample_rate, SampleFormat& data_format);
 	static std::string get_snapshot_from_instant (const std::string& session_dir);
 
+	/** a monotonic counter used for naming user-visible things uniquely
+	 * (curently the sidechain port).
+	 * Use sparingly to keep the numbers low, prefer PBD::ID for all
+	 * internal, not user-visible IDs */
+	static unsigned int next_name_id ();
+
 	std::string path() const { return _path; }
 	std::string name() const { return _name; }
 	std::string snap_name() const { return _current_snapshot_name; }
@@ -1098,6 +1104,10 @@ class LIBARDOUR_API Session : public PBD::StatefulDestructible, public PBD::Scop
 	int  create (const std::string& mix_template, BusProfile*);
 	void destroy ();
 
+	static guint _name_id_counter;
+	static void init_name_id_counter (guint n);
+	static unsigned int name_id_counter ();
+
 	enum SubState {
 		PendingDeclickIn      = 0x1,  ///< pending de-click fade-in for start
 		PendingDeclickOut     = 0x2,  ///< pending de-click fade-out for stop
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index b412841180..a1a6268f61 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -125,6 +125,7 @@ using namespace PBD;
 
 bool Session::_disable_all_loaded_plugins = false;
 bool Session::_bypass_all_loaded_plugins = false;
+guint Session::_name_id_counter = 0;
 
 PBD::Signal1<int,uint32_t> Session::AudioEngineSetupRequired;
 PBD::Signal1<void,std::string> Session::Dialog;
@@ -311,6 +312,8 @@ Session::Session (AudioEngine &eng,
 	pthread_mutex_init (&_rt_emit_mutex, 0);
 	pthread_cond_init (&_rt_emit_cond, 0);
 
+	init_name_id_counter (1); // reset for new sessions, start at 1
+
 	pre_engine_init (fullpath);
 
 	setup_lua ();
@@ -469,6 +472,24 @@ Session::~Session ()
 	destroy ();
 }
 
+unsigned int
+Session::next_name_id ()
+{
+	return g_atomic_int_add (&_name_id_counter, 1);
+}
+
+unsigned int
+Session::name_id_counter ()
+{
+	return g_atomic_int_get (&_name_id_counter);
+}
+
+void
+Session::init_name_id_counter (guint n)
+{
+	g_atomic_int_set (&_name_id_counter, n);
+}
+
 int
 Session::ensure_engine (uint32_t desired_sample_rate)
 {
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index 41fb75ccc9..975b38eee9 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -1084,6 +1084,9 @@ Session::state (bool full_state)
 	snprintf (buf, sizeof (buf), "%" PRIu64, ID::counter());
 	node->add_property ("id-counter", buf);
 
+	snprintf (buf, sizeof (buf), "%u", name_id_counter ());
+	node->add_property ("name-counter", buf);
+
 	/* save the event ID counter */
 
 	snprintf (buf, sizeof (buf), "%d", Evoral::event_id_counter());
@@ -1336,10 +1339,13 @@ Session::set_state (const XMLNode& node, int version)
 		ID::init_counter (now);
 	}
 
-        if ((prop = node.property (X_("event-counter"))) != 0) {
-                Evoral::init_event_id_counter (atoi (prop->value()));
-        }
+	if ((prop = node.property (X_("name-counter"))) != 0) {
+		init_name_id_counter (atoi (prop->value()));
+	}
 
+	if ((prop = node.property (X_("event-counter"))) != 0) {
+		Evoral::init_event_id_counter (atoi (prop->value()));
+	}
 
 	if ((child = find_named_node (node, "MIDIPorts")) != 0) {
 		_midi_ports->set_midi_port_states (child->children());