diff --git a/python/protos/ponsim.proto b/python/protos/ponsim.proto
new file mode 100644
index 0000000..74eb97e
--- /dev/null
+++ b/python/protos/ponsim.proto
@@ -0,0 +1,67 @@
+syntax = "proto3";
+
+option go_package = "github.com/opencord/voltha-protos/go/voltha";
+
+package voltha;
+
+import "google/protobuf/empty.proto";
+import "openflow_13.proto";
+
+
+message PonSimOnuDeviceInfo {
+    int32 uni_port = 1;
+    string serial_number = 2;
+}
+
+message PonSimDeviceInfo {
+    int32 nni_port = 1;
+    repeated PonSimOnuDeviceInfo onus = 2;
+}
+
+message FlowTable {
+    int32 port = 1;  // Used to address right device
+    repeated openflow_13.ofp_flow_stats flows = 2;
+}
+
+message PonSimFrame {
+    string id = 1;
+    bytes payload = 2;
+    int32 out_port = 3;
+}
+
+message PonSimPacketCounter {
+    string name = 1;
+    int64 value = 2;
+}
+
+message PonSimPortMetrics {
+    string port_name = 1;
+    repeated PonSimPacketCounter packets = 2;
+}
+
+message PonSimMetrics {
+    string device = 1;
+    repeated PonSimPortMetrics metrics = 2;
+}
+
+message PonSimMetricsRequest {
+    int32 port = 1;
+}
+
+service PonSim {
+    rpc SendFrame(PonSimFrame)
+        returns (google.protobuf.Empty) {}
+
+    rpc ReceiveFrames(google.protobuf.Empty)
+        returns (stream PonSimFrame) {}
+
+    rpc GetDeviceInfo(google.protobuf.Empty)
+        returns(PonSimDeviceInfo) {}
+
+    rpc UpdateFlowTable(FlowTable)
+        returns(google.protobuf.Empty) {}
+
+    rpc GetStats(google.protobuf.Empty)
+        returns(PonSimMetrics) {}
+
+}