diff --git a/config.c b/config.c
index acd5f45..6d00641 100644
--- a/config.c
+++ b/config.c
@@ -24,6 +24,7 @@
 #include <string.h>
 
 #include "bmc.h"
+#include "clock.h"
 #include "config.h"
 #include "ether.h"
 #include "hash.h"
@@ -135,6 +136,14 @@ static struct config_enum clock_servo_enu[] = {
 	{ NULL, 0 },
 };
 
+static struct config_enum clock_type_enu[] = {
+	{ "OC",      CLOCK_TYPE_ORDINARY },
+	{ "BC",      CLOCK_TYPE_BOUNDARY },
+	{ "P2P_TC",  CLOCK_TYPE_P2P      },
+	{ "E2E_TC",  CLOCK_TYPE_E2E      },
+	{ NULL, 0 },
+};
+
 static struct config_enum dataset_comp_enu[] = {
 	{ "ieee1588", DS_CMP_IEEE1588 },
 	{ "G.8275.x", DS_CMP_G8275    },
@@ -186,6 +195,7 @@ struct config_item config_tab[] = {
 	GLOB_ITEM_INT("clockAccuracy", 0xfe, 0, UINT8_MAX),
 	GLOB_ITEM_INT("clockClass", 248, 0, UINT8_MAX),
 	GLOB_ITEM_ENU("clock_servo", CLOCK_SERVO_PI, clock_servo_enu),
+	GLOB_ITEM_ENU("clock_type", CLOCK_TYPE_ORDINARY, clock_type_enu),
 	GLOB_ITEM_ENU("dataset_comparison", DS_CMP_IEEE1588, dataset_comp_enu),
 	PORT_ITEM_INT("delayAsymmetry", 0, INT_MIN, INT_MAX),
 	PORT_ITEM_ENU("delay_filter", FILTER_MOVING_MEDIAN, delay_filter_enu),
diff --git a/default.cfg b/default.cfg
index 408022d..f70f386 100644
--- a/default.cfg
+++ b/default.cfg
@@ -75,6 +75,7 @@ uds_address		/var/run/ptp4l
 #
 # Default interface options
 #
+clock_type		OC
 network_transport	UDPv4
 delay_mechanism		E2E
 time_stamping		hardware
diff --git a/ptp4l.8 b/ptp4l.8
index 2aee03e..003d54e 100644
--- a/ptp4l.8
+++ b/ptp4l.8
@@ -1,6 +1,6 @@
-.TH PTP4l 8 "Novemver 2017" "linuxptp"
+.TH PTP4l 8 "March 2018" "linuxptp"
 .SH NAME
-ptp4l - PTP Boundary/Ordinary Clock
+ptp4l - PTP Boundary/Ordinary/Transparent Clock
 
 .SH SYNOPSIS
 .B ptp4l
@@ -23,8 +23,8 @@ ptp4l - PTP Boundary/Ordinary Clock
 .SH DESCRIPTION
 .B ptp4l
 is an implementation of the Precision Time Protocol (PTP) according to IEEE
-standard 1588 for Linux. It implements Boundary Clock (BC) and Ordinary Clock
-(OC).
+standard 1588 for Linux. It implements Boundary Clock (BC), Ordinary Clock
+(OC), and Transparent Clock (TC).
 
 .SH OPTIONS
 .TP
@@ -425,6 +425,13 @@ number is set to the domain number), and "nullf" for a servo that
 always dials frequency offset zero (for use in SyncE nodes).
 The default is "pi."
 .TP
+.B clock_type
+Specifies the kind of PTP clock.  Valid values are "OC" for ordinary
+clock, "BC" for boundary clock, "P2P_TC" for peer to peer transparent
+clock, and "E2E_TC" for end to end transparent clock.  An multi-port
+ordinary clock will automatically be configured as a boundary clock.
+The default is "OC".
+.TP
 .B pi_proportional_const
 The proportional constant of the PI controller. When set to 0.0, the
 proportional constant will be set by the following formula from the current
diff --git a/ptp4l.c b/ptp4l.c
index ee31718..9ef8169 100644
--- a/ptp4l.c
+++ b/ptp4l.c
@@ -1,6 +1,6 @@
 /**
  * @file ptp4l.c
- * @brief PTP Boundary Clock main program
+ * @brief PTP Boundary Clock or Transparent Clock main program
  * @note Copyright (C) 2011 Richard Cochran <richardcochran@gmail.com>
  *
  * This program is free software; you can redistribute it and/or modify
@@ -59,6 +59,7 @@ static void usage(char *progname)
 		" -p [dev]  PTP hardware clock device to use, default auto\n"
 		"           (ignored for SOFTWARE/LEGACY HW time stamping)\n"
 		" -s        slave only mode (overrides configuration file)\n"
+		" -t        transparent clock\n"
 		" -l [num]  set the logging level to 'num'\n"
 		" -m        print messages to stdout\n"
 		" -q        do not print messages to the syslog\n"
@@ -71,6 +72,7 @@ static void usage(char *progname)
 int main(int argc, char *argv[])
 {
 	char *config = NULL, *req_phc = NULL, *progname;
+	enum clock_type type = CLOCK_TYPE_ORDINARY;
 	int c, err = -1, index, print_level;
 	struct clock *clock = NULL;
 	struct option *opts;
@@ -201,8 +203,44 @@ int main(int argc, char *argv[])
 		goto out;
 	}
 
-	clock = clock_create(cfg->n_interfaces > 1 ? CLOCK_TYPE_BOUNDARY :
-			     CLOCK_TYPE_ORDINARY, cfg, req_phc);
+	type = config_get_int(cfg, NULL, "clock_type");
+	switch (type) {
+	case CLOCK_TYPE_ORDINARY:
+		if (cfg->n_interfaces > 1) {
+			type = CLOCK_TYPE_BOUNDARY;
+		}
+		break;
+	case CLOCK_TYPE_BOUNDARY:
+		if (cfg->n_interfaces < 2) {
+			fprintf(stderr, "BC needs at least two interfaces\n");
+			goto out;
+		}
+		break;
+	case CLOCK_TYPE_P2P:
+		if (cfg->n_interfaces < 2) {
+			fprintf(stderr, "TC needs at least two interfaces\n");
+			goto out;
+		}
+		if (DM_P2P != config_get_int(cfg, NULL, "delay_mechanism")) {
+			fprintf(stderr, "P2P_TC needs P2P delay mechanism\n");
+			goto out;
+		}
+		break;
+	case CLOCK_TYPE_E2E:
+		if (cfg->n_interfaces < 2) {
+			fprintf(stderr, "TC needs at least two interfaces\n");
+			goto out;
+		}
+		if (DM_E2E != config_get_int(cfg, NULL, "delay_mechanism")) {
+			fprintf(stderr, "E2E_TC needs E2E delay mechanism\n");
+			goto out;
+		}
+		break;
+	case CLOCK_TYPE_MANAGEMENT:
+		goto out;
+	}
+
+	clock = clock_create(type, cfg, req_phc);
 	if (!clock) {
 		fprintf(stderr, "failed to create a clock\n");
 		goto out;