diff --git a/apm-network/src/main/proto/ApplicationRegisterService.proto b/apm-network/src/main/proto/ApplicationRegisterService.proto
new file mode 100644
index 000000000..702cde9fd
--- /dev/null
+++ b/apm-network/src/main/proto/ApplicationRegisterService.proto
@@ -0,0 +1,20 @@
+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "org.skywalking.apm.network.trace.proto";
+
+import "KeyValue.proto";
+
+//register service for ApplicationCode, this service is called when service starts.
+service ApplicationRegisterService {
+    rpc register (Application) returns (ApplicationMapping) {
+    }
+}
+
+message Application {
+    repeated string applicationCode = 1;
+}
+
+message ApplicationMapping {
+    repeated KeyValue application = 1;
+}
\ No newline at end of file
diff --git a/apm-network/src/main/proto/DiscoveryService.proto b/apm-network/src/main/proto/DiscoveryService.proto
index e9a986bbe..1f22a0df3 100644
--- a/apm-network/src/main/proto/DiscoveryService.proto
+++ b/apm-network/src/main/proto/DiscoveryService.proto
@@ -16,7 +16,7 @@ service InstanceDiscoveryService {
 }
 
 message ApplicationInstance {
-    string applicationCode = 1;
+    int32 applicationId = 1;
 }
 
 message ApplicationInstanceMapping {
@@ -45,6 +45,6 @@ message ServiceNameMappingElement {
 
 message ServiceNameElement {
     string serviceName = 1;
-    string ApplicationCode = 2;
+    int32 applicationId = 2;
 }
 
diff --git a/apm-network/src/main/proto/KeyValue.proto b/apm-network/src/main/proto/KeyValue.proto
new file mode 100644
index 000000000..f03132a38
--- /dev/null
+++ b/apm-network/src/main/proto/KeyValue.proto
@@ -0,0 +1,9 @@
+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "org.skywalking.apm.network.collecor.proto";
+
+message KeyValue {
+    string key = 1;
+    string value = 2;
+}
diff --git a/apm-network/src/main/proto/TraceSegmentService.proto b/apm-network/src/main/proto/TraceSegmentService.proto
index 2134ff219..471cac5a5 100644
--- a/apm-network/src/main/proto/TraceSegmentService.proto
+++ b/apm-network/src/main/proto/TraceSegmentService.proto
@@ -4,6 +4,7 @@ option java_multiple_files = true;
 option java_package = "org.skywalking.apm.network.trace.proto";
 
 import "Downstream.proto";
+import "KeyValue.proto";
 
 service TraceSegmentService {
     rpc collect (stream UpstreamSegment) returns (Downstream) {
@@ -65,11 +66,6 @@ enum SpanLayer {
     MQ = 3;
 }
 
-message KeyValue {
-    string key = 1;
-    string value = 2;
-}
-
 message LogMessage {
     int64 time = 1;
     repeated KeyValue data = 2;