diff --git a/api/base.proto b/api/base.proto
index 2c4b5ff31..736cb3270 100644
--- a/api/base.proto
+++ b/api/base.proto
@@ -227,3 +227,11 @@ message TransportSocket {
   // See the supported transport socket implementations for further documentation.
   google.protobuf.Struct config = 2;
 }
+
+// A percent, rounded down to the nearest 0.01%. Typically used to specify things like target
+// sampling percentages among tracing requests (as in, e.g., :ref:`HTTP Connection Manager tracing
+// <envoy_api_field_filter.network.HttpConnectionManager.tracing>`).
+message HundredthsRoundedPercent {
+  // The percent, a float between 0 and 100. Rounded to the nearest 0.01%.
+  double value = 1 [(validate.rules).double = {gte: 0, lte: 100}];
+}
diff --git a/api/filter/network/http_connection_manager.proto b/api/filter/network/http_connection_manager.proto
index f442a617a..c73f3e68d 100644
--- a/api/filter/network/http_connection_manager.proto
+++ b/api/filter/network/http_connection_manager.proto
@@ -80,6 +80,23 @@ message HttpConnectionManager {
     // populate the tag name, and the header value is used to populate the tag value. The tag is
     // created if the specified header name is present in the request's headers.
     repeated string request_headers_for_tags = 2;
+
+    // Target percentage of requests managed by this HTTP connectionmanager that will be force
+    // traced if the *x-client-trace-id* header is set. Defaults to 100%. This variable is a direct
+    // analog for the variable of the same name in the :ref:`HTTP Connection Manager
+    // <config_http_conn_man_runtime>`.
+    double client_sampling = 3 [(validate.rules).double = {gte: 0, lte: 100}];
+
+    // Target percentage of requests managed by this HTTP connection manager that will be traced
+    // after all other checks have been applied (force tracing, sampling, etc.). Defaults to 100%.
+    // This variable is a direct analog for the variable of the same name in the :ref:`HTTP
+    // Connection Manager <config_http_conn_man_runtime>`.
+    double sampling = 4 [(validate.rules).double = {gte: 0, lte: 100}];
+
+    // Target percentage of requests managed by this HTTP connection manager that will be randomly
+    // traced. Defaults to 100%. This variable is a direct analog for the variable of the same name
+    // in the :ref:`HTTP Connection Manager <config_http_conn_man_runtime>`.
+    HundredthsRoundedPercent random_sampling = 5;
   }
 
   // Presence of the object defines whether the connection manager