Reset the BWE when the network changes

webrtc/call/call.cc

Index: webrtc/call/call.cc
diff --git a/webrtc/call/call.cc b/webrtc/call/call.cc
index 3fd7a931d0cecc88cff0b30a47557db5a21ed586..e6502becd1466b3a61beb127d9b2404f1834a0bf 100644
--- a/webrtc/call/call.cc
+++ b/webrtc/call/call.cc
@@ -33,6 +33,7 @@
 #include "webrtc/modules/rtp_rtcp/include/rtp_header_parser.h"
 #include "webrtc/modules/rtp_rtcp/source/byte_io.h"
 #include "webrtc/modules/utility/include/process_thread.h"
+#include "webrtc/p2p/base/port.h"
 #include "webrtc/system_wrappers/include/cpu_info.h"
 #include "webrtc/system_wrappers/include/critical_section_wrapper.h"
 #include "webrtc/system_wrappers/include/metrics.h"
@@ -88,6 +89,8 @@ class Call : public webrtc::Call, public PacketReceiver,
       const webrtc::Call::Config::BitrateConfig& bitrate_config) override;
   void SignalNetworkState(NetworkState state) override;
 
+  void OnBestConnectionChanged(cricket::Connection* best_connection) override;
+
   void OnSentPacket(const rtc::SentPacket& sent_packet) override;
 
   // Implements BitrateObserver.
@@ -101,7 +104,6 @@ class Call : public webrtc::Call, public PacketReceiver,
                             const uint8_t* packet,
                             size_t length,
                             const PacketTime& packet_time);
-
   void ConfigureSync(const std::string& sync_group)
       EXCLUSIVE_LOCKS_REQUIRED(receive_crit_);
 
@@ -167,6 +169,9 @@ class Call : public webrtc::Call, public PacketReceiver,
   int64_t pacer_bitrate_sum_kbits_ GUARDED_BY(&bitrate_crit_);
   int64_t num_bitrate_updates_ GUARDED_BY(&bitrate_crit_);
 
+  int local_network_id_ = 0;
+  int remote_network_id_ = 0;
+
   VieRemb remb_;
   const std::unique_ptr<CongestionController> congestion_controller_;
 
@@ -570,6 +575,29 @@ void Call::SignalNetworkState(NetworkState state) {
   }
 }
 
+void Call::OnBestConnectionChanged(cricket::Connection* connection) {
+  RTC_DCHECK(configuration_thread_checker_.CalledOnValidThread());
+  // Reset the BWE estimate when network changes.
+  // Check if the network has actually changed.
+  if (connection == nullptr) {
+    LOG(LS_INFO) << "Transport channel is disconnected";
+    // TODO(honghaiz): stop sending when this happens.
+    return;
+  }
+  uint16_t local_net_id = connection->local_candidate().network_id();
+  uint16_t remote_net_id = connection->local_candidate().network_id();
+  if (local_net_id == local_network_id_ &&
+      remote_net_id == remote_network_id_) {
+    return;
+  }
+  LOG(LS_INFO) << "Network changed: new local network id " << local_net_id
+               << " new remote network id " << remote_net_id;
+  local_network_id_ = local_net_id;
+  remote_network_id_ = remote_net_id;
+  congestion_controller_->ResetBweBitrates(
+      config_.bitrate_config.start_bitrate_bps);
+}
+
 void Call::OnSentPacket(const rtc::SentPacket& sent_packet) {
   if (first_packet_sent_ms_ == -1)
     first_packet_sent_ms_ = clock_->TimeInMilliseconds();