diff --git a/apm-network/src/main/proto/DiscoveryService.proto b/apm-network/src/main/proto/DiscoveryService.proto
index 4534d04c7..e7e919b7a 100644
--- a/apm-network/src/main/proto/DiscoveryService.proto
+++ b/apm-network/src/main/proto/DiscoveryService.proto
@@ -26,6 +26,7 @@ message ApplicationInstance {
 message ApplicationInstanceMapping {
     int32 applicationId = 1;
     int32 applicationInstanceId = 2;
+    int64 registerTime = 3;
 }
 
 message ApplicationInstanceHeartbeat {