diff --git a/api/test/simulated_network.h b/api/test/simulated_network.h
index 7612923c2b..0d5c6613a6 100644
--- a/api/test/simulated_network.h
+++ b/api/test/simulated_network.h
@@ -87,6 +87,8 @@ class SimulatedNetworkInterface : public NetworkBehaviorInterface {
  public:
   // Sets a new configuration. This won't affect packets already in the pipe.
   virtual void SetConfig(const BuiltInNetworkBehaviorConfig& config) = 0;
+  virtual void UpdateConfig(
+      std::function<void(BuiltInNetworkBehaviorConfig*)> config_modifier) = 0;
   virtual void PauseTransmissionUntil(int64_t until_us) = 0;
 };
 
diff --git a/call/simulated_network.cc b/call/simulated_network.cc
index 0412129d0c..b298fdb4e2 100644
--- a/call/simulated_network.cc
+++ b/call/simulated_network.cc
@@ -111,6 +111,12 @@ void SimulatedNetwork::SetConfig(const Config& config) {
   }
 }
 
+void SimulatedNetwork::UpdateConfig(
+    std::function<void(BuiltInNetworkBehaviorConfig*)> config_modifier) {
+  rtc::CritScope crit(&config_lock_);
+  config_modifier(&config_state_.config);
+}
+
 void SimulatedNetwork::PauseTransmissionUntil(int64_t until_us) {
   rtc::CritScope crit(&config_lock_);
   config_state_.pause_transmission_until_us = until_us;
diff --git a/call/simulated_network.h b/call/simulated_network.h
index fa72762b44..2ff90ec284 100644
--- a/call/simulated_network.h
+++ b/call/simulated_network.h
@@ -62,6 +62,8 @@ class SimulatedNetwork : public SimulatedNetworkInterface {
 
   // Sets a new configuration. This won't affect packets already in the pipe.
   void SetConfig(const Config& config) override;
+  void UpdateConfig(std::function<void(BuiltInNetworkBehaviorConfig*)>
+                        config_modifier) override;
   void PauseTransmissionUntil(int64_t until_us) override;
 
   // NetworkBehaviorInterface