diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 7721f875e..2b485144e 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,6 +1,6 @@
 project(lib)
 
-file(GLOB SRCS "*.c")
+file(GLOB SRCS "agent.c" "peer_connection.c" "*.c")
 
 file(GLOB HEADERS "peer.h" "peer_connection.h" "peer_signaling.h")
 
diff --git a/src/agent.c b/src/agent.c
index 0e50ab885..c92b0f1cf 100644
--- a/src/agent.c
+++ b/src/agent.c
@@ -320,22 +320,28 @@ static void agent_create_binding_response(Agent* agent, StunMessage* msg, Addres
   stun_msg_finish(msg, STUN_CREDENTIAL_SHORT_TERM, agent->local_upwd, strlen(agent->local_upwd));
 }
 
-static void agent_create_binding_request(Agent* agent, StunMessage* msg) {
-  uint64_t tie_breaker = 0;  // always be controlled
+static void agent_create_binding_request(Agent* agent, StunMessage* msg, int is_heartbeat) {
   // send binding request
-  stun_msg_create(msg, STUN_CLASS_REQUEST | STUN_METHOD_BINDING);
-  char username[584];
-  memset(username, 0, sizeof(username));
-  snprintf(username, sizeof(username), "%s:%s", agent->remote_ufrag, agent->local_ufrag);
-  stun_msg_write_attr(msg, STUN_ATTR_TYPE_USERNAME, strlen(username), username);
-  stun_msg_write_attr(msg, STUN_ATTR_TYPE_PRIORITY, 4, (char*)&agent->nominated_pair->priority);
-  if (agent->mode == AGENT_MODE_CONTROLLING) {
-    stun_msg_write_attr(msg, STUN_ATTR_TYPE_USE_CANDIDATE, 0, NULL);
-    stun_msg_write_attr(msg, STUN_ATTR_TYPE_ICE_CONTROLLING, 8, (char*)&tie_breaker);
-  } else {
-    stun_msg_write_attr(msg, STUN_ATTR_TYPE_ICE_CONTROLLED, 8, (char*)&tie_breaker);
+  if (!is_heartbeat) {
+    uint64_t tie_breaker = 0;  // always be controlled
+    stun_msg_create(msg, STUN_CLASS_REQUEST | STUN_METHOD_BINDING);
+    char username[584];
+    memset(username, 0, sizeof(username));
+    snprintf(username, sizeof(username), "%s:%s", agent->remote_ufrag, agent->local_ufrag);
+    stun_msg_write_attr(msg, STUN_ATTR_TYPE_USERNAME, strlen(username), username);
+    stun_msg_write_attr(msg, STUN_ATTR_TYPE_PRIORITY, 4, (char*)&agent->nominated_pair->priority);
+    if (agent->mode == AGENT_MODE_CONTROLLING) {
+      stun_msg_write_attr(msg, STUN_ATTR_TYPE_USE_CANDIDATE, 0, NULL);
+      stun_msg_write_attr(msg, STUN_ATTR_TYPE_ICE_CONTROLLING, 8, (char*)&tie_breaker);
+    } else {
+      stun_msg_write_attr(msg, STUN_ATTR_TYPE_ICE_CONTROLLED, 8, (char*)&tie_breaker);
+    }
+    stun_msg_finish(msg, STUN_CREDENTIAL_SHORT_TERM, agent->remote_upwd, strlen(agent->remote_upwd));
+  }
+  else{
+    stun_msg_create(msg, STUN_CLASS_REQUEST | STUN_METHOD_BINDING);
+    stun_msg_finish(msg, STUN_CREDENTIAL_SHORT_TERM, agent->remote_upwd, strlen(agent->remote_upwd));
   }
-  stun_msg_finish(msg, STUN_CREDENTIAL_SHORT_TERM, agent->remote_upwd, strlen(agent->remote_upwd));
 }
 
 void agent_process_stun_request(Agent* agent, StunMessage* stun_msg, Address* addr) {
@@ -447,32 +453,36 @@ void agent_set_remote_description(Agent* agent, char* description) {
   LOGD("candidate pairs num: %d", agent->candidate_pairs_num);
 }
 
-int agent_connectivity_check(Agent* agent) {
+int agent_connectivity_check(Agent* agent, int is_heartbeat) {
   char addr_string[ADDRSTRLEN];
   uint8_t buf[1400];
   StunMessage msg;
+  if (!is_heartbeat) { 
+    if (agent->nominated_pair->state != ICE_CANDIDATE_STATE_INPROGRESS) {
+      LOGI("nominated pair is not in progress");
+      return -1;
+    }
+  
 
-  if (agent->nominated_pair->state != ICE_CANDIDATE_STATE_INPROGRESS) {
-    LOGI("nominated pair is not in progress");
-    return -1;
-  }
-
-  memset(&msg, 0, sizeof(msg));
+    memset(&msg, 0, sizeof(msg));
 
-  if (agent->nominated_pair->conncheck % AGENT_CONNCHECK_PERIOD == 0) {
-    addr_to_string(&agent->nominated_pair->remote->addr, addr_string, sizeof(addr_string));
-    LOGD("send binding request to remote ip: %s, port: %d", addr_string, agent->nominated_pair->remote->addr.port);
-    agent_create_binding_request(agent, &msg);
-    agent_socket_send(agent, &agent->nominated_pair->remote->addr, msg.buf, msg.size);
-  }
+    if (agent->nominated_pair->conncheck % AGENT_CONNCHECK_PERIOD == 0) {
+      addr_to_string(&agent->nominated_pair->remote->addr, addr_string, sizeof(addr_string));
+      LOGD("send binding request to remote ip: %s, port: %d", addr_string, agent->nominated_pair->remote->addr.port);
+      agent_create_binding_request(agent, &msg, 0);
+      agent_socket_send(agent, &agent->nominated_pair->remote->addr, msg.buf, msg.size);
+    }
 
-  agent_recv(agent, buf, sizeof(buf));
+    agent_recv(agent, buf, sizeof(buf));
 
-  if (agent->nominated_pair->state == ICE_CANDIDATE_STATE_SUCCEEDED) {
-    agent->selected_pair = agent->nominated_pair;
-    return 0;
+    if (agent->nominated_pair->state == ICE_CANDIDATE_STATE_SUCCEEDED) {
+      agent->selected_pair = agent->nominated_pair;
+      return 0;
+    }
+  } else {
+    agent_create_binding_request(agent, &msg, 1);
+    agent_socket_send(agent, &agent->nominated_pair->remote->addr, msg.buf, msg.size);
   }
-
   return -1;
 }
 
diff --git a/src/agent.h b/src/agent.h
index 86da0e53d..18e9e2225 100644
--- a/src/agent.h
+++ b/src/agent.h
@@ -84,7 +84,7 @@ void agent_set_remote_description(Agent* agent, char* description);
 
 int agent_select_candidate_pair(Agent* agent);
 
-int agent_connectivity_check(Agent* agent);
+int agent_connectivity_check(Agent* agent, int is_heartbeat);
 
 void agent_clear_candidates(Agent* agent);
 
diff --git a/src/peer_connection.c b/src/peer_connection.c
index c7709cfbb..2f7ab8f2c 100644
--- a/src/peer_connection.c
+++ b/src/peer_connection.c
@@ -14,6 +14,7 @@
 #include "sctp.h"
 #include "sdp.h"
 
+
 #define STATE_CHANGED(pc, curr_state)                                 \
   if (pc->oniceconnectionstatechange && pc->state != curr_state) {    \
     pc->oniceconnectionstatechange(curr_state, pc->config.user_data); \
@@ -29,6 +30,7 @@ struct PeerConnection {
 
   Sdp local_sdp;
   Sdp remote_sdp;
+  time_t last_binding_request_time;
 
   void (*onicecandidate)(char* sdp, void* user_data);
   void (*oniceconnectionstatechange)(PeerConnectionState state, void* user_data);
@@ -422,7 +424,7 @@ int peer_connection_loop(PeerConnection* pc) {
     case PEER_CONNECTION_CHECKING:
       if (agent_select_candidate_pair(&pc->agent) < 0) {
         STATE_CHANGED(pc, PEER_CONNECTION_FAILED);
-      } else if (agent_connectivity_check(&pc->agent) == 0) {
+      } else if (agent_connectivity_check(&pc->agent, 0) == 0) {
         STATE_CHANGED(pc, PEER_CONNECTION_CONNECTED);
       }
       break;
@@ -437,12 +439,19 @@ int peer_connection_loop(PeerConnection* pc) {
           sctp_create_association(&pc->sctp, &pc->dtls_srtp);
           pc->sctp.userdata = pc->config.user_data;
         }
-
+        pc->last_binding_request_time = time(NULL);
         STATE_CHANGED(pc, PEER_CONNECTION_COMPLETED);
       }
       break;
     case PEER_CONNECTION_COMPLETED:
 
+      time_t current_time = time(NULL);
+      if (current_time - pc->last_binding_request_time >= 8) {
+        agent_connectivity_check(&pc->agent, 1);
+        LOGI("heartbeat sent!");
+        pc->last_binding_request_time = current_time;
+      }
+
 #if (CONFIG_VIDEO_BUFFER_SIZE) > 0
       data = buffer_peak_head(pc->video_rb, &bytes);
       if (data) {
@@ -502,7 +511,6 @@ int peer_connection_loop(PeerConnection* pc) {
           LOGW("Unknown data");
         }
       }
-
       if (CONFIG_KEEPALIVE_TIMEOUT > 0 && (ports_get_epoch_time() - pc->agent.binding_request_time) > CONFIG_KEEPALIVE_TIMEOUT) {
         LOGI("binding request timeout");
         STATE_CHANGED(pc, PEER_CONNECTION_CLOSED);
diff --git a/src/peer_signaling.c b/src/peer_signaling.c
index 342a5798a..560715a31 100644
--- a/src/peer_signaling.c
+++ b/src/peer_signaling.c
@@ -209,9 +209,17 @@ static void peer_signaling_on_pub_event(const char* msg, size_t size) {
         break;
       }
 
-      if (state == PEER_CONNECTION_NEW) {
-        peer_connection_set_remote_description(g_ps.pc, item->valuestring);
-        result = cJSON_CreateString("");
+     switch (state) {
+        case PEER_CONNECTION_NEW:
+        case PEER_CONNECTION_DISCONNECTED:
+        case PEER_CONNECTION_FAILED:
+        case PEER_CONNECTION_CLOSED: {
+          g_ps.id = id;
+          peer_connection_set_remote_description(g_ps.pc, item->valuestring);
+        } break;
+        default: {
+          error = cJSON_CreateRaw(RPC_ERROR_INTERNAL_ERROR);
+        } break;
       }
 
     } else if (strcmp(item->valuestring, RPC_METHOD_STATE) == 0) {