diff --git a/envoy/api/v2/core/base.proto b/envoy/api/v2/core/base.proto
index 6375d87e..2553fe04 100644
--- a/envoy/api/v2/core/base.proto
+++ b/envoy/api/v2/core/base.proto
@@ -278,3 +278,15 @@ message ControlPlane {
   // the Envoy is connected to.
   string identifier = 1;
 }
+
+// Identifies the direction of the traffic relative to the local Envoy.
+enum TrafficDirection {
+  // Default option is unspecified.
+  UNSPECIFIED = 0;
+
+  // The transport is used for incoming traffic.
+  INBOUND = 1;
+
+  // The transport is used for outgoing traffic.
+  OUTBOUND = 2;
+}
diff --git a/envoy/api/v2/lds.proto b/envoy/api/v2/lds.proto
index f6081fbc..dd29659c 100644
--- a/envoy/api/v2/lds.proto
+++ b/envoy/api/v2/lds.proto
@@ -44,7 +44,7 @@ service ListenerDiscoveryService {
   }
 }
 
-// [#comment:next free field: 16]
+// [#comment:next free field: 17]
 message Listener {
   // The unique name by which this listener is known. If no name is provided,
   // Envoy will allocate an internal UUID for the listener. If the listener is to be dynamically
@@ -181,4 +181,7 @@ message Listener {
   google.protobuf.UInt32Value tcp_fast_open_queue_length = 12;
 
   reserved 14;
+
+  // Specifies the intended direction of the traffic relative to the local Envoy.
+  core.TrafficDirection traffic_direction = 16;
 }
diff --git a/envoy/config/filter/network/http_connection_manager/v2/http_connection_manager.proto b/envoy/config/filter/network/http_connection_manager/v2/http_connection_manager.proto
index f579caa5..4d662fc2 100644
--- a/envoy/config/filter/network/http_connection_manager/v2/http_connection_manager.proto
+++ b/envoy/config/filter/network/http_connection_manager/v2/http_connection_manager.proto
@@ -80,6 +80,7 @@ message HttpConnectionManager {
   google.protobuf.BoolValue add_user_agent = 6;
 
   message Tracing {
+    // [#comment:TODO(kyessenov): Align this field with listener traffic direction field.]
     enum OperationName {
       option (gogoproto.goproto_enum_prefix) = false;