diff --git a/apm-network/src/main/proto/DiscoveryService.proto b/apm-network/src/main/proto/DiscoveryService.proto
index 4534d04c7261d392132d62df9573249905a3ec9f..e7e919b7ab909c3824f5214815fb678399411c1d 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 {