diff --git a/bin/conf/main.conf b/bin/conf/main.conf
index c784709..6906ca9 100644
--- a/bin/conf/main.conf
+++ b/bin/conf/main.conf
@@ -232,4 +232,5 @@ capacity=32
 cost=32
 wlb_report_interval=10
 
-hard_balance_port=20000
\ No newline at end of file
+bfd_recv_port= 
+bfd_send_port=
\ No newline at end of file
diff --git a/src/hard_keepalive.c b/src/hard_keepalive.c
index a5d574d..5b90867 100644
--- a/src/hard_keepalive.c
+++ b/src/hard_keepalive.c
@@ -106,12 +106,13 @@ int create_send_udp_socket()
 void* thread_hard_keepalive(void *param)
 {
 	char		buf[1500] = {0};
-	long		port = (long)param;	
+	char		discriminator_temp[ID_SIZE] = {0};
+	bfd_port_t*	bfd_port = (bfd_port_t*)param;
 	int			size = 0;
 	uint32_t	src_ip = 0;	
 	int			send_rec = 0;
 	fd_set 		rset;
-	int			recv_pkt_sd = create_recv_udp_socket(htons(port));
+	int			recv_pkt_sd = create_recv_udp_socket(htons(bfd_port->recv_port));
 	int			send_pkt_sd = create_send_udp_socket();
 	
 	if(-1==recv_pkt_sd || -1==send_pkt_sd)
@@ -133,9 +134,13 @@ void* thread_hard_keepalive(void *param)
 			size = udp_socket_recv(recv_pkt_sd, &src_ip, (unsigned char*)buf, sizeof(buf));			
 			if(size>0)
 			{
+				/*交换discriminator*/
+				memcpy(discriminator_temp, buf+MY_ID_OFFSET, ID_SIZE);
+				memcpy(buf+MY_ID_OFFSET, buf+YOUR_ID_OFFSET, ID_SIZE);
+				memcpy(buf+YOUR_ID_OFFSET, discriminator_temp, ID_SIZE);
 				send_rec = udp_socket_send(send_pkt_sd,
 												src_ip,
-												htons(port),
+												htons(bfd_port->send_port),
 												(char*)buf,size);
 				if(-1==send_rec)
 				{
@@ -152,10 +157,8 @@ void* thread_hard_keepalive(void *param)
 	return NULL;
 }
 
-int hard_keepalive_run(uint32_t udp_port)
+int hard_keepalive_run(void* bfd_port)
 {
-	if(udp_port<=0) return -1;	
-	
 	pthread_t	 	thread_desc;
 	pthread_attr_t 	attr;
 
@@ -170,7 +173,7 @@ int hard_keepalive_run(uint32_t udp_port)
     {		
 		return -1;
 	}
-	if(0 != pthread_create(&(thread_desc), &(attr), thread_hard_keepalive, (void*)udp_port)) 
+	if(0 != pthread_create(&(thread_desc), &(attr), thread_hard_keepalive, (void*)bfd_port)) 
     {
 		pthread_attr_destroy(&(attr));
 		return -1;
diff --git a/src/hard_keepalive.h b/src/hard_keepalive.h
index 3b51d01..7eaa7d3 100644
--- a/src/hard_keepalive.h
+++ b/src/hard_keepalive.h
@@ -1,14 +1,35 @@
 #ifndef _HARD_KEEPALIVE_H
 #define _HARD_KEEPALIVE_H
 
+typedef struct bfd_port_s
+{		
+	uint32_t	recv_port;
+	uint32_t	send_port;
+}bfd_port_t;
+
+#define	MY_ID_OFFSET	4
+#define	YOUR_ID_OFFSET	8
+#define	ID_SIZE			4
+typedef struct bfd_header_s
+{
+    unsigned char version_diag;
+    unsigned char flags;
+    unsigned char detect_time_multiplier;
+    unsigned char length;
+    unsigned char my_discriminator[4]; /* 业?潞? 虏虏芒*/
+    unsigned char your_discriminator[4];
+    unsigned char desired_min_tx_interval[4];
+    unsigned char required_min_rx_interval[4];
+    unsigned char required_min_echo_interval[4];
+}bfd_header_t; 
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-/*return 0:succ -1:fail*/
-int hard_keepalive_run(uint32_t udp_port);
 
+/*return 0:succ -1:fail*/
+int hard_keepalive_run(void* bfd_port);
 
 #ifdef __cplusplus
 }
diff --git a/src/main.c b/src/main.c
index d8885f5..dd93bb3 100644
--- a/src/main.c
+++ b/src/main.c
@@ -740,7 +740,8 @@ int read_conf_and_init(const char* filename)
 	MESA_load_profile_uint_def(filename, "WLB", "cost", (unsigned int*)&g_frag_cfg.cost,32);		
 	MESA_load_profile_uint_def(filename, "WLB", "wlb_report_interval", (unsigned int*)&g_frag_cfg.wlb_report_interval,10);		
 	MESA_load_profile_uint_def(filename, "WLB", "enable_override", (unsigned int*)&g_frag_cfg.enable_override,0);	
-	MESA_load_profile_uint_def(filename, "WLB", "hard_balance_port", (unsigned int*)&g_frag_cfg.hard_balance_port,0);	
+	MESA_load_profile_uint_def(filename, "WLB", "bfd_recv_port", (unsigned int*)&g_frag_cfg.bfd_recv_port,0);	
+	MESA_load_profile_uint_def(filename, "WLB", "bfd_send_port", (unsigned int*)&g_frag_cfg.bfd_send_port,0);	
 
 	/*send bizman :粗拼装往前端发数据，监听响应端口*/	
 	MESA_load_profile_short_def(filename, "NETWORK", "BizmanAckPort", (short*)&g_frag_cfg.bizman_ack_port,22084);		
@@ -1281,9 +1282,12 @@ int   main(int argc, char **argv)
     	}
 	}
 
-	if(g_frag_cfg.hard_balance_port>0)
+	if(g_frag_cfg.bfd_recv_port>0 && g_frag_cfg.bfd_send_port>0)
 	{
-		hard_keepalive_run(g_frag_cfg.hard_balance_port);
+		bfd_port_t bfd_port;
+		bfd_port.recv_port = g_frag_cfg.bfd_recv_port;
+		bfd_port.send_port = g_frag_cfg.bfd_send_port;
+		hard_keepalive_run(&bfd_port);
 	}	
 	
 	while(1)
diff --git a/src/main.h b/src/main.h
index 27f4659..0a06c3d 100644
--- a/src/main.h
+++ b/src/main.h
@@ -241,7 +241,8 @@ typedef struct frag_rssb_configure_s
 	uint32_t                    health_check_port;
 	int16_t						save_media;
 	
-	uint32_t                    hard_balance_port;
+	uint32_t                    bfd_recv_port;
+	uint32_t                    bfd_send_port;
 }frag_rssb_configure_t;
 
 typedef struct frag_rssb_status_s