diff --git a/protos/ponsim.proto b/protos/ponsim.proto
index e477d98..1cd9e4e 100644
--- a/protos/ponsim.proto
+++ b/protos/ponsim.proto
@@ -44,6 +44,10 @@
     repeated PonSimPortMetrics metrics = 2;
 }
 
+message PonSimMetricsRequest {
+    int32 port = 1;
+}
+
 service PonSim {
     rpc SendFrame(PonSimFrame)
         returns (google.protobuf.Empty) {}