diff --git a/makefile b/makefile
index a6e3eb5..5dc5fdc 100644
--- a/makefile
+++ b/makefile
@@ -25,9 +25,9 @@ LDLIBS	= -lm -lrt $(EXTRA_LDFLAGS)
 PRG	= ptp4l hwstamp_ctl nsm phc2sys phc_ctl pmc timemaster
 OBJ     = bmc.o clock.o clockadj.o clockcheck.o config.o e2e_tc.o fault.o \
  filter.o fsm.o hash.o linreg.o mave.o mmedian.o msg.o ntpshm.o nullf.o phc.o \
- pi.o port.o print.o ptp4l.o p2p_tc.o raw.o rtnl.o servo.o sk.o stats.o tc.o \
- telecom.o tlv.o transport.o tsproc.o udp.o udp6.o uds.o unicast_fsm.o util.o \
- version.o
+ pi.o port.o port_signaling.o print.o ptp4l.o p2p_tc.o raw.o rtnl.o servo.o \
+ sk.o stats.o tc.o telecom.o tlv.o transport.o tsproc.o udp.o udp6.o uds.o \
+ unicast_fsm.o util.o version.o
 
 OBJECTS	= $(OBJ) hwstamp_ctl.o nsm.o phc2sys.o phc_ctl.o pmc.o pmc_common.o \
  sysoff.o timemaster.o
diff --git a/port_private.h b/port_private.h
index e1adeb9..777de02 100644
--- a/port_private.h
+++ b/port_private.h
@@ -84,6 +84,7 @@ struct port {
 	struct {
 		UInteger16 announce;
 		UInteger16 delayreq;
+		UInteger16 signaling;
 		UInteger16 sync;
 	} seqnum;
 	tmv_t peer_delay;
@@ -160,6 +161,9 @@ int port_set_delay_tmo(struct port *p);
 int port_set_qualification_tmo(struct port *p);
 void port_show_transition(struct port *p, enum port_state next,
 			  enum fsm_event event);
+struct ptp_message *port_signaling_construct(struct port *p,
+					     struct address *address,
+					     struct PortIdentity *tpid);
 int port_tx_announce(struct port *p, struct address *dst);
 int port_tx_sync(struct port *p, struct address *dst);
 int process_announce(struct port *p, struct ptp_message *m);
diff --git a/port_signaling.c b/port_signaling.c
new file mode 100644
index 0000000..c8b46e9
--- /dev/null
+++ b/port_signaling.c
@@ -0,0 +1,46 @@
+/**
+ * @file port_signaling.c
+ * @brief Implements signaling messages
+ * @note Copyright (C) 2018 Richard Cochran <richardcochran@gmail.com>
+ *
+ * This program 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA.
+ */
+#include "port_private.h"
+
+struct ptp_message *port_signaling_construct(struct port *p,
+					     struct address *address,
+					     struct PortIdentity *tpid)
+{
+	struct ptp_message *msg;
+
+	msg = msg_allocate();
+	if (!msg) {
+		return NULL;
+	}
+	msg->hwts.type                 = p->timestamping;
+	msg->header.tsmt               = SIGNALING | p->transportSpecific;
+	msg->header.ver                = PTP_VERSION;
+	msg->header.messageLength      = sizeof(struct signaling_msg);
+	msg->header.domainNumber       = clock_domain_number(p->clock);
+	msg->header.sourcePortIdentity = p->portIdentity;
+	msg->header.sequenceId         = p->seqnum.signaling++;
+	msg->header.control            = CTL_OTHER;
+	msg->header.logMessageInterval = 0x7F;
+	msg->signaling.targetPortIdentity = *tpid;
+	msg->header.flagField[0] |= UNICAST;
+	msg->address = *address;
+
+	return msg;
+}