diff --git a/kernel/mars_client.c b/kernel/mars_client.c
index 0bfe2f2b..b7f97e77 100644
--- a/kernel/mars_client.c
+++ b/kernel/mars_client.c
@@ -144,14 +144,12 @@ void _kill_channel(struct client_channel *ch)
 		mars_shutdown_socket(&ch->socket);
 	}
 	_kill_thread(&ch->receiver, "receiver");
-	if (ch->is_open) {
+	if (ch->ch_state >= CL_CHANNEL_OPEN) {
 		MARS_DBG("close socket\n");
 		mars_put_socket(&ch->socket);
 	}
 	ch->recv_error = 0;
-	ch->is_used = false;
-	ch->is_open = false;
-	ch->is_connected = false;
+	ch->ch_state = CL_CHANNEL_INITIALIZED;
 	/* Re-Submit any waiting requests
 	 */
 	_do_resubmit(ch);
@@ -218,7 +216,7 @@ int _setup_channel(struct client_bundle *bundle, int ch_nr)
 	ch->socket.s_shutdown_on_err = true;
 	ch->socket.s_send_abort = mars_client_abort;
 	ch->socket.s_recv_abort = mars_client_abort;
-	ch->is_open = true;
+	ch->ch_state = CL_CHANNEL_OPEN;
 
 	ch->receiver.thread =
 		brick_thread_create(receiver_thread, ch,
@@ -228,10 +226,12 @@ int _setup_channel(struct client_bundle *bundle, int ch_nr)
 				    ch_nr);
 	if (unlikely(!ch->receiver.thread)) {
 		MARS_ERR("cannot start receiver thread %d, status = %d\n", ch_nr, status);
+		mars_shutdown_socket(&ch->socket);
+		ch->ch_state = CL_CHANNEL_INITIALIZED;
 		status = -ENOENT;
 		goto done;
 	}
-	ch->is_used = true;
+	ch->ch_state = CL_CHANNEL_USED;
 	atomic_inc(&client_receiver_count);
 
 done:
@@ -266,7 +266,7 @@ void _maintain_bundle(struct client_bundle *bundle)
 	for (i = 0; i < MAX_CLIENT_CHANNELS; i++) {
 		struct client_channel *ch = &bundle->channel[i];
 
-		if (!ch->is_used ||
+		if (ch->ch_state <= CL_CHANNEL_USED ||
 		    (!ch->recv_error && mars_socket_is_alive(&ch->socket)))
 			continue;
 
@@ -294,8 +294,7 @@ struct client_channel *_get_channel(struct client_bundle *bundle, int min_channe
 	}
 	/* Use higher channels only when the first one is fully established */
 	if (max_channel > 1 &&
-	    (!bundle->channel[0].is_connected ||
-	     !bundle->channel[0].is_open)) {
+	    (bundle->channel[0].ch_state < CL_CHANNEL_CONNECTED)) {
 		max_channel = 1;
 		min_channel = 0;
 	    }
@@ -308,7 +307,9 @@ struct client_channel *_get_channel(struct client_bundle *bundle, int min_channe
 	if (best_channel >= max_channel)
 		best_channel = min_channel;
 	res = &bundle->channel[best_channel];
-	if (res->is_connected && !res->recv_error && mars_socket_is_alive(&res->socket)) {
+	if (res->ch_state >= CL_CHANNEL_CONNECTED &&
+	    !res->recv_error &&
+	    mars_socket_is_alive(&res->socket)) {
 		res->current_space = mars_socket_send_space_available(&res->socket);
 		if (res->current_space > (PAGE_SIZE + PAGE_SIZE / 4))
 			goto found;
@@ -326,7 +327,7 @@ struct client_channel *_get_channel(struct client_bundle *bundle, int min_channe
 		long this_space;
 
 		// create new channels when necessary
-		if (unlikely(!ch->is_open)) {
+		if (ch->ch_state < CL_CHANNEL_OPEN) {
 			int status;
 			// only create one new channel at a time
 			status = _setup_channel(bundle, i);
@@ -360,7 +361,7 @@ struct client_channel *_get_channel(struct client_bundle *bundle, int min_channe
 	}
 
 	// send initial connect command
-	if (unlikely(!res->is_connected)) {
+	if (unlikely(res->ch_state < CL_CHANNEL_CONNECTED)) {
 		struct mars_cmd cmd = {
 			.cmd_code = CMD_CONNECT,
 			.cmd_str1 = bundle->path,
@@ -377,7 +378,7 @@ struct client_channel *_get_channel(struct client_bundle *bundle, int min_channe
 			res = NULL;
 			goto done;
 		}
-		res->is_connected = true;
+		res->ch_state = CL_CHANNEL_CONNECTED;
 	}
 
 found:
@@ -907,7 +908,7 @@ void _do_timeout_all(struct client_output *output, bool force)
 	for (i = 0; i < MAX_CLIENT_CHANNELS; i++) {
 		struct client_channel *ch = &output->bundle.channel[i];
 
-		if (!ch->is_used)
+		if (ch->ch_state < CL_CHANNEL_USED)
 			continue;
 		_do_timeout(output, &ch->wait_list, &rounds, force);
 	}
@@ -1101,7 +1102,7 @@ static int client_switch(struct client_brick *brick)
 		int i;
 
 		for (i = 0; i < MAX_CLIENT_CHANNELS; i++)
-			if (output->bundle.channel[i].is_connected)
+			if (output->bundle.channel[i].ch_state >= CL_CHANNEL_CONNECTED)
 				socket_count++;
 		brick->socket_count = socket_count;
 		if (brick->power.led_on)
diff --git a/kernel/mars_client.h b/kernel/mars_client.h
index 16f3b3bb..421c465a 100644
--- a/kernel/mars_client.h
+++ b/kernel/mars_client.h
@@ -75,6 +75,13 @@ struct client_threadinfo {
 	struct task_struct *thread;
 };
 
+enum CL_CHANNEL_STATE {
+	CL_CHANNEL_INITIALIZED,
+	CL_CHANNEL_OPEN,	/* socket is estabished */
+	CL_CHANNEL_USED,	/* receiver thread has been created */
+	CL_CHANNEL_CONNECTED,	/* first communication had no error */
+};
+
 struct client_channel {
 	struct mars_socket socket;
 	struct client_threadinfo receiver;
@@ -84,9 +91,7 @@ struct client_channel {
 	int recv_error;
 	int thread_restart_count;
 	int ch_nr;
-	bool is_used;
-	bool is_open;
-	bool is_connected;
+	enum CL_CHANNEL_STATE ch_state;
 };
 
 struct client_bundle {