diff --git a/mesh/cfgmod-server.c b/mesh/cfgmod-server.c
index a1f682765..35b9b0af0 100644
--- a/mesh/cfgmod-server.c
+++ b/mesh/cfgmod-server.c
@@ -67,7 +67,7 @@ static void send_pub_status(struct mesh_node *node, uint16_t net_idx,
 	}
 
 	mesh_model_send(node, dst, src, APP_IDX_DEV_LOCAL, net_idx, DEFAULT_TTL,
-								msg, n);
+								false, msg, n);
 }
 
 static bool config_pub_get(struct mesh_node *node, uint16_t net_idx,
@@ -211,8 +211,8 @@ static void send_sub_status(struct mesh_node *node, uint16_t net_idx,
 		n += 2;
 	}
 
-	mesh_model_send(node, dst, src, APP_IDX_DEV_LOCAL, net_idx,
-							DEFAULT_TTL, msg, n);
+	mesh_model_send(node, dst, src, APP_IDX_DEV_LOCAL, net_idx, DEFAULT_TTL,
+								false, msg, n);
 }
 
 static bool config_sub_get(struct mesh_node *node, uint16_t net_idx,
@@ -272,7 +272,7 @@ static bool config_sub_get(struct mesh_node *node, uint16_t net_idx,
 	*msg_status = (uint8_t) status;
 
 	mesh_model_send(node, dst, src, APP_IDX_DEV_LOCAL, net_idx, DEFAULT_TTL,
-									msg, n);
+								false, msg, n);
 	return true;
 }
 
@@ -450,7 +450,7 @@ static void send_model_app_status(struct mesh_node *node, uint16_t net_idx,
 	n += 2;
 
 	mesh_model_send(node, dst, src, APP_IDX_DEV_LOCAL, net_idx, DEFAULT_TTL,
-									msg, n);
+								false, msg, n);
 }
 
 static void model_app_list(struct mesh_node *node, uint16_t net_idx,
@@ -505,7 +505,7 @@ static void model_app_list(struct mesh_node *node, uint16_t net_idx,
 	if (result >= 0) {
 		*status = result;
 		mesh_model_send(node, dst, src, APP_IDX_DEV_LOCAL, net_idx,
-							DEFAULT_TTL, msg, n);
+						DEFAULT_TTL, false, msg, n);
 	}
 
 	l_free(msg);
@@ -1234,7 +1234,7 @@ static bool cfg_srv_pkt(uint16_t src, uint16_t dst, uint16_t app_idx,
 	if (n) {
 		/* print_packet("App Tx", long_msg ? long_msg : msg, n); */
 		mesh_model_send(node, dst, src,
-				APP_IDX_DEV_LOCAL, net_idx, DEFAULT_TTL,
+				APP_IDX_DEV_LOCAL, net_idx, DEFAULT_TTL, false,
 				long_msg ? long_msg : msg, n);
 	}
 	l_free(long_msg);
diff --git a/mesh/model.c b/mesh/model.c
index d11c95ab9..945583324 100644
--- a/mesh/model.c
+++ b/mesh/model.c
@@ -540,7 +540,7 @@ static void cmplt(uint16_t remote, uint8_t status,
 
 static bool msg_send(struct mesh_node *node, bool credential, uint16_t src,
 		uint32_t dst, uint16_t app_idx, uint16_t net_idx,
-		uint8_t *label, uint8_t ttl,
+		uint8_t *label, uint8_t ttl, bool segmented,
 		const void *msg, uint16_t msg_len)
 {
 	uint8_t dev_key[16];
@@ -597,8 +597,8 @@ static bool msg_send(struct mesh_node *node, bool credential, uint16_t src,
 	/* print_packet("Encrypted with", key, 16); */
 
 	ret = mesh_net_app_send(net, credential, src, dst, key_aid, net_idx,
-					ttl, seq_num, iv_index, szmic, out,
-					out_len, cmplt, NULL);
+					ttl, seq_num, iv_index, segmented,
+					szmic, out, out_len, cmplt, NULL);
 done:
 	l_free(out);
 	return ret;
@@ -1098,14 +1098,14 @@ int mesh_model_publish(struct mesh_node *node, uint32_t mod_id,
 
 	result = msg_send(node, mod->pub->credential != 0, src,
 				mod->pub->addr, mod->pub->idx, net_idx,
-				label, ttl, msg, msg_len);
+				label, ttl, false, msg, msg_len);
 
 	return result ? MESH_ERROR_NONE : MESH_ERROR_FAILED;
 }
 
 bool mesh_model_send(struct mesh_node *node, uint16_t src, uint16_t dst,
 					uint16_t app_idx, uint16_t net_idx,
-					uint8_t ttl,
+					uint8_t ttl, bool segmented,
 					const void *msg, uint16_t msg_len)
 {
 	/* print_packet("Mod Tx", msg, msg_len); */
@@ -1120,7 +1120,7 @@ bool mesh_model_send(struct mesh_node *node, uint16_t src, uint16_t dst,
 		return false;
 
 	return msg_send(node, false, src, dst, app_idx, net_idx,
-						NULL, ttl, msg, msg_len);
+					NULL, ttl, segmented, msg, msg_len);
 }
 
 int mesh_model_pub_set(struct mesh_node *node, uint16_t addr, uint32_t id,
diff --git a/mesh/model.h b/mesh/model.h
index 153ab9bfd..f8e0f9d37 100644
--- a/mesh/model.h
+++ b/mesh/model.h
@@ -95,7 +95,7 @@ int mesh_model_sub_get(struct mesh_node *node, uint16_t addr, uint32_t id,
 uint16_t mesh_model_cfg_blk(uint8_t *pkt);
 bool mesh_model_send(struct mesh_node *node, uint16_t src, uint16_t dst,
 					uint16_t app_idx, uint16_t net_idx,
-					uint8_t ttl,
+					uint8_t ttl, bool segmented,
 					const void *msg, uint16_t msg_len);
 int mesh_model_publish(struct mesh_node *node, uint32_t mod_id, uint16_t src,
 				uint8_t ttl, const void *msg, uint16_t msg_len);
diff --git a/mesh/net.c b/mesh/net.c
index d3325e073..c89f55a9e 100644
--- a/mesh/net.c
+++ b/mesh/net.c
@@ -139,6 +139,7 @@ struct mesh_net {
 	struct l_queue *replay_cache;
 	struct l_queue *sar_in;
 	struct l_queue *sar_out;
+	struct l_queue *sar_queue;
 	struct l_queue *frnd_msgs;
 	struct l_queue *friends;
 	struct l_queue *negotiations;
@@ -182,6 +183,7 @@ struct mesh_sar {
 	uint16_t remote;
 	uint16_t len;
 	bool szmic;
+	bool segmented;
 	bool frnd;
 	bool frnd_cred;
 	uint8_t ttl;
@@ -662,6 +664,7 @@ struct mesh_net *mesh_net_new(struct mesh_node *node)
 	net->msg_cache = l_queue_new();
 	net->sar_in = l_queue_new();
 	net->sar_out = l_queue_new();
+	net->sar_queue = l_queue_new();
 	net->frnd_msgs = l_queue_new();
 	net->destinations = l_queue_new();
 	net->app_keys = l_queue_new();
@@ -687,6 +690,7 @@ void mesh_net_free(struct mesh_net *net)
 	l_queue_destroy(net->replay_cache, l_free);
 	l_queue_destroy(net->sar_in, mesh_sar_free);
 	l_queue_destroy(net->sar_out, mesh_sar_free);
+	l_queue_destroy(net->sar_queue, mesh_sar_free);
 	l_queue_destroy(net->frnd_msgs, l_free);
 	l_queue_destroy(net->friends, mesh_friend_free);
 	l_queue_destroy(net->negotiations, mesh_friend_free);
@@ -1657,6 +1661,21 @@ static void outmsg_to(struct l_timeout *msg_timeout, void *user_data)
 }
 
 static void outseg_to(struct l_timeout *seg_timeout, void *user_data);
+
+static void send_queued_sar(struct mesh_net *net, uint16_t dst)
+{
+	struct mesh_sar *sar = l_queue_remove_if(net->sar_queue,
+			match_sar_remote, L_UINT_TO_PTR(dst));
+
+	if (!sar) return;
+
+	/* Out to current outgoing, and immediate expire Seg TO */
+	l_queue_push_head(net->sar_out, sar);
+	sar->seg_timeout = NULL;
+	sar->msg_timeout = l_timeout_create(MSG_TO, outmsg_to, net, NULL);
+	outseg_to(NULL, net);
+}
+
 static void ack_received(struct mesh_net *net, bool timeout,
 				uint16_t src, uint16_t dst,
 				uint16_t seq0, uint32_t ack_flag)
@@ -1692,6 +1711,7 @@ static void ack_received(struct mesh_net *net, bool timeout,
 					outgoing->len - 4, outgoing->user_data);
 
 		l_queue_remove(net->sar_out, outgoing);
+		send_queued_sar(net, outgoing->remote);
 		mesh_sar_free(outgoing);
 
 		return;
@@ -1701,10 +1721,10 @@ static void ack_received(struct mesh_net *net, bool timeout,
 
 	ack_copy &= outgoing->flags;
 
-	for (i = 0; i <= SEG_MAX(outgoing->len); i++, seg_flag <<= 1) {
+	for (i = 0; i <= SEG_MAX(true, outgoing->len); i++, seg_flag <<= 1) {
 		if (seg_flag & ack_flag) {
 			l_debug("Skipping Seg %d of %d",
-					i, SEG_MAX(outgoing->len));
+					i, SEG_MAX(true, outgoing->len));
 			continue;
 		}
 
@@ -1741,7 +1761,7 @@ static bool msg_rxed(struct mesh_net *net, bool frnd, uint32_t iv_index,
 					uint8_t ttl, uint32_t seq,
 					uint16_t net_idx,
 					uint16_t src, uint16_t dst,
-					uint8_t key_aid,
+					uint8_t key_aid, bool segmented,
 					bool szmic, uint16_t seqZero,
 					const uint8_t *data, uint16_t size)
 {
@@ -1768,7 +1788,7 @@ static bool msg_rxed(struct mesh_net *net, bool frnd, uint32_t iv_index,
 			hdr |= true << SEG_HDR_SHIFT;
 			hdr |= szmic << SZMIC_HDR_SHIFT;
 			hdr |= (seqZero & SEQ_ZERO_MASK) << SEQ_ZERO_HDR_SHIFT;
-			hdr |= SEG_MAX(size) << SEGN_HDR_SHIFT;
+			hdr |= SEG_MAX(true, size) << SEGN_HDR_SHIFT;
 		}
 
 		if (friend_packet_queue(net, iv_index, false, frnd_ttl,
@@ -1967,7 +1987,7 @@ static bool seg_rxed(struct mesh_net *net, bool frnd, uint32_t iv_index,
 		l_info("RXed (old: %04x %06x size:%d) %d of %d",
 					seqZero, seq, size, segO, segN);
 		/* Sanity Check--> certain things must match */
-		if (SEG_MAX(sar_in->len) != segN ||
+		if (SEG_MAX(true, sar_in->len) != segN ||
 				sar_in->key_aid != key_aid)
 			return false;
 
@@ -2022,8 +2042,8 @@ static bool seg_rxed(struct mesh_net *net, bool frnd, uint32_t iv_index,
 
 		msg_rxed(net, frnd, iv_index, ttl, seq, net_idx,
 				sar_in->remote, dst,
-				key_aid,
-				szmic, sar_in->seqZero,
+				key_aid, true, szmic,
+				sar_in->seqZero,
 				sar_in->buf, sar_in->len);
 
 		/* Kill Inter-Seg timeout */
@@ -2426,7 +2446,8 @@ static enum _relay_advice packet_received(void *user_data,
 						net_idx,
 						net_src, net_dst,
 						net_key_id,
-						false, net_seq & SEQ_ZERO_MASK,
+						false, false,
+						net_seq & SEQ_ZERO_MASK,
 						msg, app_msg_len);
 		}
 
@@ -2539,7 +2560,8 @@ static void iv_upd_to(struct l_timeout *upd_timeout, void *user_data)
 
 	switch (net->iv_upd_state) {
 	case IV_UPD_UPDATING:
-		if (l_queue_length(net->sar_out)) {
+		if (l_queue_length(net->sar_out) ||
+					l_queue_length(net->sar_queue)) {
 			l_info("don't leave IV Update until sar_out empty");
 			l_timeout_modify(net->iv_update_timeout, 10);
 			break;
@@ -3043,12 +3065,12 @@ static bool send_seg(struct mesh_net *net, struct mesh_sar *msg, uint8_t segO)
 	uint8_t gatt_data[30];
 	uint8_t *packet = gatt_data;
 	uint8_t packet_len;
-	uint8_t segN = SEG_MAX(msg->len);
+	uint8_t segN = SEG_MAX(msg->segmented, msg->len);
 	uint16_t seg_off = SEG_OFF(segO);
 	uint32_t key_id = 0;
 	uint32_t seq_num;
 
-	if (segN) {
+	if (msg->segmented) {
 		/* Send each segment on unique seq_num */
 		seq_num = mesh_net_next_seq_num(net);
 
@@ -3075,7 +3097,7 @@ static bool send_seg(struct mesh_net *net, struct mesh_sar *msg, uint8_t segO)
 					seq_num,
 					msg->src, msg->remote,
 					0,
-					segN ? true : false, msg->key_aid,
+					msg->segmented, msg->key_aid,
 					msg->szmic, false, msg->seqZero,
 					segO, segN,
 					msg->buf + seg_off, seg_len,
@@ -3169,7 +3191,8 @@ void mesh_net_send_seg(struct mesh_net *net, uint32_t net_key_id,
 bool mesh_net_app_send(struct mesh_net *net, bool frnd_cred, uint16_t src,
 				uint16_t dst, uint8_t key_aid, uint16_t net_idx,
 				uint8_t ttl, uint32_t seq, uint32_t iv_index,
-				bool szmic, const void *msg, uint16_t msg_len,
+				bool segmented, bool szmic,
+				const void *msg, uint16_t msg_len,
 				mesh_net_status_func_t status_func,
 				void *user_data)
 {
@@ -3189,14 +3212,16 @@ bool mesh_net_app_send(struct mesh_net *net, bool frnd_cred, uint16_t src,
 	if (ttl == DEFAULT_TTL)
 		ttl = net->default_ttl;
 
-	seg_max = SEG_MAX(msg_len);
+	segmented |= szmic;
+	seg_max = SEG_MAX(segmented, msg_len);
+	segmented |= !!(seg_max);
 
 	/* First enqueue to any Friends and internal models */
 	result = msg_rxed(net, false, iv_index, ttl,
 				seq,
 				net_idx,
 				src, dst,
-				key_aid,
+				key_aid, segmented,
 				szmic, seq & SEQ_ZERO_MASK,
 				msg, msg_len);
 
@@ -3207,13 +3232,6 @@ bool mesh_net_app_send(struct mesh_net *net, bool frnd_cred, uint16_t src,
 			(dst >= net->src_addr && dst <= net->last_addr))
 		return true;
 
-	/* If Segmented, Cancel any OB segmented message to same DST */
-	if (seg_max) {
-		payload = l_queue_remove_if(net->sar_out, match_sar_remote,
-							L_UINT_TO_PTR(dst));
-		mesh_sar_free(payload);
-	}
-
 	/* Setup OTA Network send */
 	payload = mesh_sar_new(msg_len);
 	memcpy(payload->buf, msg, msg_len);
@@ -3224,16 +3242,30 @@ bool mesh_net_app_send(struct mesh_net *net, bool frnd_cred, uint16_t src,
 	payload->szmic = szmic;
 	payload->frnd_cred = frnd_cred;
 	payload->key_aid = key_aid;
-	if (seg_max) {
+	payload->iv_index = mesh_net_get_iv_index(net);
+	payload->seqAuth = seq;
+	payload->segmented = segmented;
+	if (segmented) {
 		payload->flags = 0xffffffff >> (31 - seg_max);
 		payload->seqZero = seq & SEQ_ZERO_MASK;
-	}
+		payload->status_func = status_func;
+		payload->user_data = user_data;
+		payload->id = ++net->sar_id_next;
 
-	payload->iv_index = mesh_net_get_iv_index(net);
-	payload->seqAuth = seq;
+		/* Single thread SAR messages to same Unicast DST */
+		if (NULL != l_queue_find(net->sar_out, match_sar_remote,
+							L_UINT_TO_PTR(dst))) {
+			/* Delay sending Outbound SAR unless prior
+			 * SAR to same DST has completed */
+
+			l_info("OB-Queued SeqZero: %4.4x", payload->seqZero);
+			l_queue_push_tail(net->sar_queue, payload);
+			return true;
+		}
+	}
 
 	result = true;
-	if (!IS_UNICAST(dst) && seg_max) {
+	if (!IS_UNICAST(dst) && segmented) {
 		int i;
 
 		for (i = 0; i < 4; i++) {
@@ -3246,7 +3278,7 @@ bool mesh_net_app_send(struct mesh_net *net, bool frnd_cred, uint16_t src,
 	}
 
 	/* Reliable: Cache; Unreliable: Flush*/
-	if (result && seg_max && IS_UNICAST(dst)) {
+	if (result && segmented && IS_UNICAST(dst)) {
 		l_queue_push_head(net->sar_out, payload);
 		payload->seg_timeout =
 			l_timeout_create(SEG_TO, outseg_to, net, NULL);
diff --git a/mesh/net.h b/mesh/net.h
index 6fedd69d7..cb90c1d92 100644
--- a/mesh/net.h
+++ b/mesh/net.h
@@ -40,8 +40,9 @@ struct mesh_node;
 
 #define MAX_UNSEG_LEN	15 /* msg_len == 11 + sizeof(MIC) */
 #define MAX_SEG_LEN	12 /* UnSeg length - 3 octets overhead */
-#define SEG_MAX(len)	(((len) <= MAX_UNSEG_LEN) ? 0 : \
+#define SEG_MAX(seg, len) ((!seg && len <= MAX_UNSEG_LEN) ? 0 : \
 						(((len) - 1) / MAX_SEG_LEN))
+
 #define SEG_OFF(seg)	((seg) * MAX_SEG_LEN)
 #define MAX_SEG_TO_LEN(seg)	((seg) ? SEG_OFF((seg) + 1) : MAX_UNSEG_LEN)
 
@@ -311,7 +312,8 @@ void mesh_net_transport_send(struct mesh_net *net, uint32_t key_id,
 bool mesh_net_app_send(struct mesh_net *net, bool frnd_cred, uint16_t src,
 				uint16_t dst, uint8_t key_id, uint16_t net_idx,
 				uint8_t ttl, uint32_t seq, uint32_t iv_index,
-				bool szmic, const void *msg, uint16_t msg_len,
+				bool segmented, bool szmic,
+				const void *msg, uint16_t msg_len,
 				mesh_net_status_func_t status_func,
 				void *user_data);
 void mesh_net_ack_send(struct mesh_net *net, uint32_t key_id,
diff --git a/mesh/node.c b/mesh/node.c
index d4be070fa..1b7dea736 100644
--- a/mesh/node.c
+++ b/mesh/node.c
@@ -1830,7 +1830,7 @@ static struct l_dbus_message *send_call(struct l_dbus *dbus,
 		return dbus_error(msg, MESH_ERROR_INVALID_ARGS,
 						"Invalid key_index");
 
-	if (!mesh_model_send(node, src, dst, app_idx, 0, DEFAULT_TTL,
+	if (!mesh_model_send(node, src, dst, app_idx, 0, DEFAULT_TTL, false,
 								data, len))
 		return dbus_error(msg, MESH_ERROR_FAILED, NULL);
 
@@ -1879,7 +1879,7 @@ static struct l_dbus_message *dev_key_send_call(struct l_dbus *dbus,
 
 	app_idx = remote ? APP_IDX_DEV_REMOTE : APP_IDX_DEV_LOCAL;
 	if (!mesh_model_send(node, src, dst, app_idx, net_idx, DEFAULT_TTL,
-								data, len))
+							true, data, len))
 		return dbus_error(msg, MESH_ERROR_NOT_FOUND, NULL);
 
 	return l_dbus_message_new_method_return(msg);
@@ -1937,7 +1937,7 @@ static struct l_dbus_message *add_netkey_call(struct l_dbus *dbus,
 	l_put_le16(sub_idx, &data[2]);
 
 	if (!mesh_model_send(node, src, dst, APP_IDX_DEV_REMOTE, net_idx,
-							DEFAULT_TTL, data, 20))
+						DEFAULT_TTL, false, data, 20))
 		return dbus_error(msg, MESH_ERROR_NOT_FOUND, NULL);
 
 	return l_dbus_message_new_method_return(msg);
@@ -2003,7 +2003,7 @@ static struct l_dbus_message *add_appkey_call(struct l_dbus *dbus,
 	data[3] = app_idx >> 4;
 
 	if (!mesh_model_send(node, src, dst, APP_IDX_DEV_REMOTE, net_idx,
-							DEFAULT_TTL, data, 20))
+						DEFAULT_TTL, false, data, 20))
 		return dbus_error(msg, MESH_ERROR_NOT_FOUND, NULL);
 
 	return l_dbus_message_new_method_return(msg);
diff --git a/unit/test-mesh-crypto.c b/unit/test-mesh-crypto.c
index 32c46a54e..0043b0b10 100644
--- a/unit/test-mesh-crypto.c
+++ b/unit/test-mesh-crypto.c
@@ -1017,7 +1017,7 @@ static void check_encrypt(const struct mesh_crypto_test *keys)
 		app_msg = l_util_from_hexstring(keys->app_msg, &app_msg_len);
 
 		if (keys->szmic) {
-			seg_max = SEG_MAX(app_msg_len + 8);
+			seg_max = SEG_MAX(keys->segmented, app_msg_len + 8);
 			enc_msg = l_malloc(app_msg_len + 8);
 			mesh_crypto_application_encrypt(key_aid, keys->app_seq,
 					keys->net_src, keys->net_dst,
@@ -1028,7 +1028,7 @@ static void check_encrypt(const struct mesh_crypto_test *keys)
 					enc_msg, &app_mic64, sizeof(app_mic64));
 			l_put_be64(app_mic64, enc_msg + app_msg_len);
 		} else {
-			seg_max = SEG_MAX(app_msg_len + 4);
+			seg_max = SEG_MAX(keys->segmented, app_msg_len + 4);
 			enc_msg = l_malloc(app_msg_len + 4);
 			mesh_crypto_application_encrypt(key_aid, keys->app_seq,
 					keys->net_src, keys->net_dst,
