diff --git a/call/call_config.h b/call/call_config.h
index d111b53..a6f7a96 100644
--- a/call/call_config.h
+++ b/call/call_config.h
@@ -47,7 +47,7 @@
   // FecController to use for this call.
   FecControllerFactoryInterface* fec_controller_factory = nullptr;
 
-  // Task Queue Factory to be used in this call.
+  // Task Queue Factory to be used in this call. Required.
   TaskQueueFactory* task_queue_factory = nullptr;
 
   // NetworkStatePredictor to use for this call.