diff --git a/quic/core/http/quic_spdy_client_session_test.cc b/quic/core/http/quic_spdy_client_session_test.cc
index 77d105c..0d6b36c 100644
--- a/quic/core/http/quic_spdy_client_session_test.cc
+++ b/quic/core/http/quic_spdy_client_session_test.cc
@@ -504,7 +504,7 @@
   session_->ProcessUdpPacket(client_address, server_address, valid_packet);
 
   // Verify that a non-decryptable packet doesn't close the connection.
-  QuicFramerPeer::SetLastSerializedConnectionId(
+  QuicFramerPeer::SetLastSerializedServerConnectionId(
       QuicConnectionPeer::GetFramer(connection_), connection_id);
   ParsedQuicVersionVector versions = SupportedVersions(GetParam());
   QuicConnectionId destination_connection_id = EmptyQuicConnectionId();
@@ -549,7 +549,7 @@
   QuicConnectionId destination_connection_id =
       session_->connection()->connection_id();
   QuicConnectionId source_connection_id = EmptyQuicConnectionId();
-  QuicFramerPeer::SetLastSerializedConnectionId(
+  QuicFramerPeer::SetLastSerializedServerConnectionId(
       QuicConnectionPeer::GetFramer(connection_), destination_connection_id);
   ParsedQuicVersionVector versions = {GetParam()};
   bool version_flag = false;
diff --git a/quic/core/quic_connection.cc b/quic/core/quic_connection.cc
index e61bae4..a8672f5 100644
--- a/quic/core/quic_connection.cc
+++ b/quic/core/quic_connection.cc
@@ -219,7 +219,7 @@
   (perspective_ == Perspective::IS_SERVER ? "Server: " : "Client: ")
 
 QuicConnection::QuicConnection(
-    QuicConnectionId connection_id,
+    QuicConnectionId server_connection_id,
     QuicSocketAddress initial_peer_address,
     QuicConnectionHelperInterface* helper,
     QuicAlarmFactory* alarm_factory,
@@ -230,7 +230,7 @@
     : framer_(supported_versions,
               helper->GetClock()->ApproximateNow(),
               perspective,
-              connection_id.length()),
+              server_connection_id.length()),
       current_packet_content_(NO_FRAMES_RECEIVED),
       is_current_packet_connectivity_probing_(false),
       current_effective_peer_migration_type_(NO_CHANGE),
@@ -242,7 +242,7 @@
       encryption_level_(ENCRYPTION_INITIAL),
       clock_(helper->GetClock()),
       random_generator_(helper->GetRandomGenerator()),
-      connection_id_(connection_id),
+      server_connection_id_(server_connection_id),
       peer_address_(initial_peer_address),
       direct_peer_address_(initial_peer_address),
       active_effective_peer_migration_type_(NO_CHANGE),
@@ -302,7 +302,10 @@
           &arena_)),
       visitor_(nullptr),
       debug_visitor_(nullptr),
-      packet_generator_(connection_id_, &framer_, random_generator_, this),
+      packet_generator_(server_connection_id_,
+                        &framer_,
+                        random_generator_,
+                        this),
       idle_network_timeout_(QuicTime::Delta::Infinite()),
       handshake_timeout_(QuicTime::Delta::Infinite()),
       time_of_first_packet_sent_after_receiving_(
@@ -374,13 +377,14 @@
     QUIC_RELOADABLE_FLAG_COUNT(quic_use_uber_received_packet_manager);
   }
   QUIC_DLOG(INFO) << ENDPOINT
-                  << "Created connection with connection_id: " << connection_id
+                  << "Created connection with server connection_id: "
+                  << server_connection_id
                   << " and version: " << ParsedQuicVersionToString(version());
 
-  QUIC_BUG_IF(!QuicUtils::IsConnectionIdValidForVersion(connection_id,
+  QUIC_BUG_IF(!QuicUtils::IsConnectionIdValidForVersion(server_connection_id,
                                                         transport_version()))
-      << "QuicConnection: attempted to use connection ID " << connection_id
-      << " which is invalid with version "
+      << "QuicConnection: attempted to use server connection ID "
+      << server_connection_id << " which is invalid with version "
       << QuicVersionToString(transport_version());
 
   framer_.set_visitor(this);
@@ -444,7 +448,7 @@
   sent_packet_manager_.SetFromConfig(config);
   if (config.HasReceivedBytesForConnectionId() &&
       can_truncate_connection_ids_) {
-    packet_generator_.SetConnectionIdLength(
+    packet_generator_.SetServerConnectionIdLength(
         config.ReceivedBytesForConnectionId());
   }
   max_undecryptable_packets_ = config.max_undecryptable_packets();
@@ -592,7 +596,7 @@
   // Check that any public reset packet with a different connection ID that was
   // routed to this QuicConnection has been redirected before control reaches
   // here.  (Check for a bug regression.)
-  DCHECK_EQ(connection_id_, packet.connection_id);
+  DCHECK_EQ(server_connection_id_, packet.connection_id);
   DCHECK_EQ(perspective_, Perspective::IS_CLIENT);
   if (debug_visitor_ != nullptr) {
     debug_visitor_->OnPublicResetPacket(packet);
@@ -683,7 +687,7 @@
   // Check that any public reset packet with a different connection ID that was
   // routed to this QuicConnection has been redirected before control reaches
   // here.  (Check for a bug regression.)
-  DCHECK_EQ(connection_id_, packet.connection_id);
+  DCHECK_EQ(server_connection_id_, packet.connection_id);
   if (perspective_ == Perspective::IS_SERVER) {
     const std::string error_details =
         "Server received version negotiation packet.";
@@ -766,10 +770,10 @@
 void QuicConnection::OnRetryPacket(QuicConnectionId original_connection_id,
                                    QuicConnectionId new_connection_id,
                                    QuicStringPiece retry_token) {
-  if (original_connection_id != connection_id_) {
+  if (original_connection_id != server_connection_id_) {
     QUIC_DLOG(ERROR) << "Ignoring RETRY with original connection ID "
                      << original_connection_id << " not matching expected "
-                     << connection_id_ << " token "
+                     << server_connection_id_ << " token "
                      << QuicTextUtils::HexEncode(retry_token);
     return;
   }
@@ -780,17 +784,18 @@
   }
   retry_has_been_parsed_ = true;
   QUIC_DLOG(INFO) << "Received RETRY, replacing connection ID "
-                  << connection_id_ << " with " << new_connection_id
+                  << server_connection_id_ << " with " << new_connection_id
                   << ", received token "
                   << QuicTextUtils::HexEncode(retry_token);
-  connection_id_ = new_connection_id;
-  packet_generator_.SetConnectionId(connection_id_);
+  server_connection_id_ = new_connection_id;
+  packet_generator_.SetServerConnectionId(server_connection_id_);
   packet_generator_.SetRetryToken(retry_token);
 
   // Reinstall initial crypters because the connection ID changed.
   CrypterPair crypters;
-  CryptoUtils::CreateTlsInitialCrypters(
-      Perspective::IS_CLIENT, transport_version(), connection_id_, &crypters);
+  CryptoUtils::CreateTlsInitialCrypters(Perspective::IS_CLIENT,
+                                        transport_version(),
+                                        server_connection_id_, &crypters);
   SetEncrypter(ENCRYPTION_INITIAL, std::move(crypters.encrypter));
   InstallDecrypter(ENCRYPTION_INITIAL, std::move(crypters.decrypter));
 }
@@ -817,21 +822,23 @@
   QuicConnectionId server_connection_id =
       GetServerConnectionIdAsRecipient(header, perspective_);
 
-  if (server_connection_id == connection_id_ ||
+  if (server_connection_id == server_connection_id_ ||
       HasIncomingConnectionId(server_connection_id)) {
     return true;
   }
 
   if (PacketCanReplaceConnectionId(header, perspective_)) {
     QUIC_DLOG(INFO) << ENDPOINT << "Accepting packet with new connection ID "
-                    << server_connection_id << " instead of " << connection_id_;
+                    << server_connection_id << " instead of "
+                    << server_connection_id_;
     return true;
   }
 
   ++stats_.packets_dropped;
   QUIC_DLOG(INFO) << ENDPOINT
                   << "Ignoring packet from unexpected ConnectionId: "
-                  << server_connection_id << " instead of " << connection_id_;
+                  << server_connection_id << " instead of "
+                  << server_connection_id_;
   if (debug_visitor_ != nullptr) {
     debug_visitor_->OnIncorrectConnectionId(server_connection_id);
   }
@@ -851,7 +858,7 @@
   // routed to this QuicConnection has been redirected before control reaches
   // here.
   DCHECK(GetServerConnectionIdAsRecipient(header, perspective_) ==
-             connection_id_ ||
+             server_connection_id_ ||
          HasIncomingConnectionId(
              GetServerConnectionIdAsRecipient(header, perspective_)) ||
          PacketCanReplaceConnectionId(header, perspective_));
@@ -1109,7 +1116,7 @@
                    << " packet_number:" << last_header_.packet_number
                    << " largest seen with ack:"
                    << GetLargestReceivedPacketWithAck()
-                   << " connection_id: " << connection_id_;
+                   << " server_connection_id: " << server_connection_id_;
     // A new ack has a diminished largest_observed value.
     // If this was an old packet, we wouldn't even have checked.
     CloseConnection(QUIC_INVALID_ACK_DATA, "Largest observed too low.",
@@ -2132,11 +2139,12 @@
   }
 
   if (PacketCanReplaceConnectionId(header, perspective_) &&
-      connection_id_ != header.source_connection_id) {
-    QUIC_DLOG(INFO) << ENDPOINT << "Replacing connection ID " << connection_id_
-                    << " with " << header.source_connection_id;
-    connection_id_ = header.source_connection_id;
-    packet_generator_.SetConnectionId(connection_id_);
+      server_connection_id_ != header.source_connection_id) {
+    QUIC_DLOG(INFO) << ENDPOINT << "Replacing connection ID "
+                    << server_connection_id_ << " with "
+                    << header.source_connection_id;
+    server_connection_id_ = header.source_connection_id;
+    packet_generator_.SetServerConnectionId(server_connection_id_);
   }
 
   if (!ValidateReceivedPacketNumber(header.packet_number)) {
@@ -3578,7 +3586,7 @@
 
   QUIC_DLOG(INFO) << ENDPOINT
                   << "Sending path probe packet for connection_id = "
-                  << connection_id_;
+                  << server_connection_id_;
 
   OwningSerializedPacketPointer probing_packet;
   if (transport_version() != QUIC_VERSION_99) {
diff --git a/quic/core/quic_connection.h b/quic/core/quic_connection.h
index 8c8ed2b..b274266 100644
--- a/quic/core/quic_connection.h
+++ b/quic/core/quic_connection.h
@@ -341,7 +341,7 @@
   // |initial_peer_address| using |writer| to write packets. |owns_writer|
   // specifies whether the connection takes ownership of |writer|. |helper| must
   // outlive this connection.
-  QuicConnection(QuicConnectionId connection_id,
+  QuicConnection(QuicConnectionId server_connection_id,
                  QuicSocketAddress initial_peer_address,
                  QuicConnectionHelperInterface* helper,
                  QuicAlarmFactory* alarm_factory,
@@ -582,7 +582,7 @@
   const QuicSocketAddress& effective_peer_address() const {
     return effective_peer_address_;
   }
-  QuicConnectionId connection_id() const { return connection_id_; }
+  QuicConnectionId connection_id() const { return server_connection_id_; }
   const QuicClock* clock() const { return clock_; }
   QuicRandom* random_generator() const { return random_generator_; }
   QuicByteCount max_packet_length() const;
@@ -1168,7 +1168,7 @@
   const QuicClock* clock_;
   QuicRandom* random_generator_;
 
-  QuicConnectionId connection_id_;
+  QuicConnectionId server_connection_id_;
   // Address on the last successfully processed packet received from the
   // direct peer.
   QuicSocketAddress self_address_;
diff --git a/quic/core/quic_connection_test.cc b/quic/core/quic_connection_test.cc
index 4ecb780..0d09430 100644
--- a/quic/core/quic_connection_test.cc
+++ b/quic/core/quic_connection_test.cc
@@ -938,7 +938,7 @@
       peer_creator_.SetEncrypter(
           level, QuicMakeUnique<NullEncrypter>(peer_framer_.perspective()));
     }
-    QuicFramerPeer::SetLastSerializedConnectionId(
+    QuicFramerPeer::SetLastSerializedServerConnectionId(
         QuicConnectionPeer::GetFramer(&connection_), connection_id_);
     if (version().transport_version > QUIC_VERSION_43) {
       EXPECT_TRUE(QuicConnectionPeer::GetNoStopWaitingFrames(&connection_));
diff --git a/quic/core/quic_dispatcher.cc b/quic/core/quic_dispatcher.cc
index 9af5f84..049a63f 100644
--- a/quic/core/quic_dispatcher.cc
+++ b/quic/core/quic_dispatcher.cc
@@ -115,17 +115,17 @@
 // list manager.
 class StatelessConnectionTerminator {
  public:
-  StatelessConnectionTerminator(QuicConnectionId connection_id,
+  StatelessConnectionTerminator(QuicConnectionId server_connection_id,
                                 const ParsedQuicVersion version,
                                 QuicConnectionHelperInterface* helper,
                                 QuicTimeWaitListManager* time_wait_list_manager)
-      : connection_id_(connection_id),
+      : server_connection_id_(server_connection_id),
         framer_(ParsedQuicVersionVector{version},
                 /*unused*/ QuicTime::Zero(),
                 Perspective::IS_SERVER,
                 /*unused*/ kQuicDefaultConnectionIdLength),
         collector_(helper->GetStreamSendBufferAllocator()),
-        creator_(connection_id, &framer_, &collector_),
+        creator_(server_connection_id, &framer_, &collector_),
         time_wait_list_manager_(time_wait_list_manager) {
     framer_.set_data_producer(&collector_);
   }
@@ -154,7 +154,7 @@
     creator_.Flush();
     DCHECK_EQ(1u, collector_.packets()->size());
     time_wait_list_manager_->AddConnectionIdToTimeWait(
-        connection_id_, ietf_quic,
+        server_connection_id_, ietf_quic,
         QuicTimeWaitListManager::SEND_TERMINATION_PACKETS,
         quic::ENCRYPTION_INITIAL, collector_.packets());
   }
@@ -195,14 +195,15 @@
       creator_.Flush();
     }
     time_wait_list_manager_->AddConnectionIdToTimeWait(
-        connection_id_, ietf_quic,
+        server_connection_id_, ietf_quic,
         QuicTimeWaitListManager::SEND_TERMINATION_PACKETS, ENCRYPTION_INITIAL,
         collector_.packets());
-    DCHECK(time_wait_list_manager_->IsConnectionIdInTimeWait(connection_id_));
+    DCHECK(time_wait_list_manager_->IsConnectionIdInTimeWait(
+        server_connection_id_));
   }
 
  private:
-  QuicConnectionId connection_id_;
+  QuicConnectionId server_connection_id_;
   QuicFramer framer_;
   // Set as the visitor of |creator_| to collect any generated packets.
   PacketCollector collector_;
@@ -214,7 +215,7 @@
 class ChloAlpnExtractor : public ChloExtractor::Delegate {
  public:
   void OnChlo(QuicTransportVersion version,
-              QuicConnectionId connection_id,
+              QuicConnectionId server_connection_id,
               const CryptoHandshakeMessage& chlo) override {
     QuicStringPiece alpn_value;
     if (chlo.GetStringPiece(kALPN, &alpn_value)) {
@@ -247,16 +248,17 @@
 
   // ChloExtractor::Delegate implementation.
   void OnChlo(QuicTransportVersion version,
-              QuicConnectionId connection_id,
+              QuicConnectionId server_connection_id,
               const CryptoHandshakeMessage& chlo) override {
     // Extract the ALPN
-    ChloAlpnExtractor::OnChlo(version, connection_id, chlo);
+    ChloAlpnExtractor::OnChlo(version, server_connection_id, chlo);
     if (helper_->CanAcceptClientHello(chlo, client_address_, peer_address_,
                                       self_address_, &error_details_)) {
       can_accept_ = true;
       rejector_->OnChlo(
-          version, connection_id,
-          helper_->GenerateConnectionIdForReject(version, connection_id), chlo);
+          version, server_connection_id,
+          helper_->GenerateConnectionIdForReject(version, server_connection_id),
+          chlo);
     }
   }
 
@@ -305,7 +307,7 @@
       last_error_(QUIC_NO_ERROR),
       new_sessions_allowed_per_event_loop_(0u),
       accept_new_connections_(true),
-      allow_short_initial_connection_ids_(false),
+      allow_short_initial_server_connection_ids_(false),
       last_version_label_(0),
       expected_connection_id_length_(expected_connection_id_length),
       should_update_expected_connection_id_length_(false),
@@ -382,34 +384,35 @@
   //            the next packet does not use them incorrectly.
 }
 
-QuicConnectionId QuicDispatcher::MaybeReplaceConnectionId(
-    QuicConnectionId connection_id,
+QuicConnectionId QuicDispatcher::MaybeReplaceServerConnectionId(
+    QuicConnectionId server_connection_id,
     ParsedQuicVersion version) {
   const uint8_t expected_connection_id_length =
       no_framer_ ? expected_connection_id_length_
                  : framer_.GetExpectedConnectionIdLength();
-  if (connection_id.length() == expected_connection_id_length) {
-    return connection_id;
+  if (server_connection_id.length() == expected_connection_id_length) {
+    return server_connection_id;
   }
   DCHECK(QuicUtils::VariableLengthConnectionIdAllowedForVersion(
       version.transport_version));
-  auto it = connection_id_map_.find(connection_id);
+  auto it = connection_id_map_.find(server_connection_id);
   if (it != connection_id_map_.end()) {
     return it->second;
   }
   QuicConnectionId new_connection_id =
       session_helper_->GenerateConnectionIdForReject(version.transport_version,
-                                                     connection_id);
+                                                     server_connection_id);
   DCHECK_EQ(expected_connection_id_length, new_connection_id.length());
-  connection_id_map_.insert(std::make_pair(connection_id, new_connection_id));
-  QUIC_DLOG(INFO) << "Replacing incoming connection ID " << connection_id
+  connection_id_map_.insert(
+      std::make_pair(server_connection_id, new_connection_id));
+  QUIC_DLOG(INFO) << "Replacing incoming connection ID " << server_connection_id
                   << " with " << new_connection_id;
   return new_connection_id;
 }
 
 bool QuicDispatcher::OnUnauthenticatedPublicHeader(
     const QuicPacketHeader& header) {
-  current_connection_id_ = header.destination_connection_id;
+  current_server_connection_id_ = header.destination_connection_id;
 
   // Port zero is only allowed for unidirectional UDP, so is disallowed by QUIC.
   // Given that we can't even send a reply rejecting the packet, just drop the
@@ -423,7 +426,7 @@
   if (header.destination_connection_id_included != CONNECTION_ID_PRESENT) {
     return false;
   }
-  QuicConnectionId connection_id = header.destination_connection_id;
+  QuicConnectionId server_connection_id = header.destination_connection_id;
 
   // The IETF spec requires the client to generate an initial server
   // connection ID that is at least 64 bits long. After that initial
@@ -433,42 +436,43 @@
   const uint8_t expected_connection_id_length =
       no_framer_ ? expected_connection_id_length_
                  : framer_.GetExpectedConnectionIdLength();
-  if (connection_id.length() < kQuicMinimumInitialConnectionIdLength &&
-      connection_id.length() < expected_connection_id_length &&
-      !allow_short_initial_connection_ids_) {
+  if (server_connection_id.length() < kQuicMinimumInitialConnectionIdLength &&
+      server_connection_id.length() < expected_connection_id_length &&
+      !allow_short_initial_server_connection_ids_) {
     DCHECK(header.version_flag);
     DCHECK(QuicUtils::VariableLengthConnectionIdAllowedForVersion(
         header.version.transport_version));
     QUIC_DLOG(INFO) << "Packet with short destination connection ID "
-                    << connection_id << " expected "
+                    << server_connection_id << " expected "
                     << static_cast<int>(expected_connection_id_length);
-    ProcessUnauthenticatedHeaderFate(kFateTimeWait, connection_id, header.form,
-                                     header.version_flag, header.version);
+    ProcessUnauthenticatedHeaderFate(kFateTimeWait, server_connection_id,
+                                     header.form, header.version_flag,
+                                     header.version);
     return false;
   }
 
   // Packets with connection IDs for active connections are processed
   // immediately.
-  auto it = session_map_.find(connection_id);
+  auto it = session_map_.find(server_connection_id);
   if (it != session_map_.end()) {
-    DCHECK(!buffered_packets_.HasBufferedPackets(connection_id));
+    DCHECK(!buffered_packets_.HasBufferedPackets(server_connection_id));
     it->second->ProcessUdpPacket(current_self_address_, current_peer_address_,
                                  *current_packet_);
     return false;
   }
 
-  if (buffered_packets_.HasChloForConnection(connection_id)) {
-    BufferEarlyPacket(connection_id, header.form != GOOGLE_QUIC_PACKET,
+  if (buffered_packets_.HasChloForConnection(server_connection_id)) {
+    BufferEarlyPacket(server_connection_id, header.form != GOOGLE_QUIC_PACKET,
                       header.version);
     return false;
   }
 
   // Check if we are buffering packets for this connection ID
-  if (temporarily_buffered_connections_.find(connection_id) !=
+  if (temporarily_buffered_connections_.find(server_connection_id) !=
       temporarily_buffered_connections_.end()) {
     // This packet was received while the a CHLO for the same connection ID was
     // being processed.  Buffer it.
-    BufferEarlyPacket(connection_id, header.form != GOOGLE_QUIC_PACKET,
+    BufferEarlyPacket(server_connection_id, header.form != GOOGLE_QUIC_PACKET,
                       header.version);
     return false;
   }
@@ -483,7 +487,7 @@
     return false;
   }
 
-  if (time_wait_list_manager_->IsConnectionIdInTimeWait(connection_id)) {
+  if (time_wait_list_manager_->IsConnectionIdInTimeWait(server_connection_id)) {
     // This connection ID is already in time-wait state.
     time_wait_list_manager_->ProcessPacket(
         current_self_address_, current_peer_address_,
@@ -513,7 +517,7 @@
         // Since the version is not supported, send a version negotiation
         // packet and stop processing the current packet.
         time_wait_list_manager()->SendVersionNegotiationPacket(
-            connection_id, header.form != GOOGLE_QUIC_PACKET,
+            server_connection_id, header.form != GOOGLE_QUIC_PACKET,
             GetSupportedVersions(), current_self_address_,
             current_peer_address_, GetPerPacketContext());
       }
@@ -539,25 +543,25 @@
 }
 
 void QuicDispatcher::ProcessHeader(const QuicPacketHeader& header) {
-  QuicConnectionId connection_id = header.destination_connection_id;
+  QuicConnectionId server_connection_id = header.destination_connection_id;
   // Packet's connection ID is unknown.  Apply the validity checks.
   QuicPacketFate fate = ValidityChecks(header);
   if (fate == kFateProcess) {
     // Execute stateless rejection logic to determine the packet fate, then
     // invoke ProcessUnauthenticatedHeaderFate.
-    MaybeRejectStatelessly(connection_id, header.form, header.version_flag,
-                           header.version);
+    MaybeRejectStatelessly(server_connection_id, header.form,
+                           header.version_flag, header.version);
   } else {
     // If the fate is already known, process it without executing stateless
     // rejection logic.
-    ProcessUnauthenticatedHeaderFate(fate, connection_id, header.form,
+    ProcessUnauthenticatedHeaderFate(fate, server_connection_id, header.form,
                                      header.version_flag, header.version);
   }
 }
 
 void QuicDispatcher::ProcessUnauthenticatedHeaderFate(
     QuicPacketFate fate,
-    QuicConnectionId connection_id,
+    QuicConnectionId server_connection_id,
     PacketHeaderFormat form,
     bool version_flag,
     ParsedQuicVersion version) {
@@ -570,33 +574,36 @@
       // MaybeRejectStatelessly or OnExpiredPackets might have already added the
       // connection to time wait, in which case it should not be added again.
       if (!GetQuicReloadableFlag(quic_use_cheap_stateless_rejects) ||
-          !time_wait_list_manager_->IsConnectionIdInTimeWait(connection_id)) {
+          !time_wait_list_manager_->IsConnectionIdInTimeWait(
+              server_connection_id)) {
         // Add this connection_id to the time-wait state, to safely reject
         // future packets.
-        QUIC_DLOG(INFO) << "Adding connection ID " << connection_id
+        QUIC_DLOG(INFO) << "Adding connection ID " << server_connection_id
                         << " to time-wait list.";
         QUIC_CODE_COUNT(quic_reject_fate_time_wait);
         StatelesslyTerminateConnection(
-            connection_id, form, version_flag, version, QUIC_HANDSHAKE_FAILED,
-            "Reject connection",
+            server_connection_id, form, version_flag, version,
+            QUIC_HANDSHAKE_FAILED, "Reject connection",
             quic::QuicTimeWaitListManager::SEND_STATELESS_RESET);
       }
-      DCHECK(time_wait_list_manager_->IsConnectionIdInTimeWait(connection_id));
+      DCHECK(time_wait_list_manager_->IsConnectionIdInTimeWait(
+          server_connection_id));
       time_wait_list_manager_->ProcessPacket(
-          current_self_address_, current_peer_address_, connection_id, form,
-          GetPerPacketContext());
+          current_self_address_, current_peer_address_, server_connection_id,
+          form, GetPerPacketContext());
 
       // Any packets which were buffered while the stateless rejector logic was
       // running should be discarded.  Do not inform the time wait list manager,
       // which should already have a made a decision about sending a reject
       // based on the CHLO alone.
-      buffered_packets_.DiscardPackets(connection_id);
+      buffered_packets_.DiscardPackets(server_connection_id);
       break;
     case kFateBuffer:
       // This packet is a non-CHLO packet which has arrived before the
       // corresponding CHLO, *or* this packet was received while the
       // corresponding CHLO was being processed.  Buffer it.
-      BufferEarlyPacket(connection_id, form != GOOGLE_QUIC_PACKET, version);
+      BufferEarlyPacket(server_connection_id, form != GOOGLE_QUIC_PACKET,
+                        version);
       break;
     case kFateDrop:
       // Do nothing with the packet.
@@ -775,13 +782,13 @@
   DeleteSessions();
 }
 
-void QuicDispatcher::OnConnectionClosed(QuicConnectionId connection_id,
+void QuicDispatcher::OnConnectionClosed(QuicConnectionId server_connection_id,
                                         QuicErrorCode error,
                                         const std::string& error_details,
                                         ConnectionCloseSource source) {
-  auto it = session_map_.find(connection_id);
+  auto it = session_map_.find(server_connection_id);
   if (it == session_map_.end()) {
-    QUIC_BUG << "ConnectionId " << connection_id
+    QUIC_BUG << "ConnectionId " << server_connection_id
              << " does not exist in the session map.  Error: "
              << QuicErrorCodeToString(error);
     QUIC_BUG << QuicStackTrace();
@@ -789,7 +796,7 @@
   }
 
   QUIC_DLOG_IF(INFO, error != QUIC_NO_ERROR)
-      << "Closing connection (" << connection_id
+      << "Closing connection (" << server_connection_id
       << ") due to error: " << QuicErrorCodeToString(error)
       << ", with details: " << error_details;
 
@@ -828,13 +835,13 @@
 void QuicDispatcher::OnStopSendingReceived(const QuicStopSendingFrame& frame) {}
 
 void QuicDispatcher::OnConnectionAddedToTimeWaitList(
-    QuicConnectionId connection_id) {
-  QUIC_DLOG(INFO) << "Connection " << connection_id
+    QuicConnectionId server_connection_id) {
+  QUIC_DLOG(INFO) << "Connection " << server_connection_id
                   << " added to time wait list.";
 }
 
 void QuicDispatcher::StatelesslyTerminateConnection(
-    QuicConnectionId connection_id,
+    QuicConnectionId server_connection_id,
     PacketHeaderFormat format,
     bool version_flag,
     ParsedQuicVersion version,
@@ -844,26 +851,27 @@
   if (format != IETF_QUIC_LONG_HEADER_PACKET &&
       (!GetQuicReloadableFlag(quic_terminate_gquic_connection_as_ietf) ||
        !version_flag)) {
-    QUIC_DVLOG(1) << "Statelessly terminating " << connection_id
+    QUIC_DVLOG(1) << "Statelessly terminating " << server_connection_id
                   << " based on a non-ietf-long packet, action:" << action
                   << ", error_code:" << error_code
                   << ", error_details:" << error_details;
     time_wait_list_manager_->AddConnectionIdToTimeWait(
-        connection_id, format != GOOGLE_QUIC_PACKET, action, ENCRYPTION_INITIAL,
-        nullptr);
+        server_connection_id, format != GOOGLE_QUIC_PACKET, action,
+        ENCRYPTION_INITIAL, nullptr);
     return;
   }
 
   // If the version is known and supported by framer, send a connection close.
   if (IsSupportedVersion(version)) {
     QUIC_DVLOG(1)
-        << "Statelessly terminating " << connection_id
+        << "Statelessly terminating " << server_connection_id
         << " based on an ietf-long packet, which has a supported version:"
         << version << ", error_code:" << error_code
         << ", error_details:" << error_details;
 
-    StatelessConnectionTerminator terminator(
-        connection_id, version, helper_.get(), time_wait_list_manager_.get());
+    StatelessConnectionTerminator terminator(server_connection_id, version,
+                                             helper_.get(),
+                                             time_wait_list_manager_.get());
     // This also adds the connection to time wait list.
     if (format == GOOGLE_QUIC_PACKET) {
       QUIC_RELOADABLE_FLAG_COUNT_N(quic_terminate_gquic_connection_as_ietf, 1,
@@ -875,7 +883,7 @@
   }
 
   QUIC_DVLOG(1)
-      << "Statelessly terminating " << connection_id
+      << "Statelessly terminating " << server_connection_id
       << " based on an ietf-long packet, which has an unsupported version:"
       << version << ", error_code:" << error_code
       << ", error_details:" << error_details;
@@ -883,13 +891,13 @@
   // with an empty version list, which can be understood by the client.
   std::vector<std::unique_ptr<QuicEncryptedPacket>> termination_packets;
   termination_packets.push_back(QuicFramer::BuildVersionNegotiationPacket(
-      connection_id, /*ietf_quic=*/format != GOOGLE_QUIC_PACKET,
+      server_connection_id, /*ietf_quic=*/format != GOOGLE_QUIC_PACKET,
       ParsedQuicVersionVector{UnsupportedQuicVersion()}));
   if (format == GOOGLE_QUIC_PACKET) {
     QUIC_RELOADABLE_FLAG_COUNT_N(quic_terminate_gquic_connection_as_ietf, 2, 2);
   }
   time_wait_list_manager()->AddConnectionIdToTimeWait(
-      connection_id, /*ietf_quic=*/format != GOOGLE_QUIC_PACKET,
+      server_connection_id, /*ietf_quic=*/format != GOOGLE_QUIC_PACKET,
       QuicTimeWaitListManager::SEND_TERMINATION_PACKETS, ENCRYPTION_INITIAL,
       &termination_packets);
 }
@@ -913,7 +921,7 @@
   DCHECK(!no_framer_);
   QUIC_BUG_IF(
       !time_wait_list_manager_->IsConnectionIdInTimeWait(
-          current_connection_id_) &&
+          current_server_connection_id_) &&
       !ShouldCreateSessionForUnknownVersion(framer_.last_version_label()))
       << "Unexpected version mismatch: "
       << QuicVersionLabelToString(framer_.last_version_label());
@@ -1090,11 +1098,11 @@
 }
 
 void QuicDispatcher::OnExpiredPackets(
-    QuicConnectionId connection_id,
+    QuicConnectionId server_connection_id,
     BufferedPacketList early_arrived_packets) {
   QUIC_CODE_COUNT(quic_reject_buffered_packets_expired);
   StatelesslyTerminateConnection(
-      connection_id,
+      server_connection_id,
       early_arrived_packets.ietf_quic ? IETF_QUIC_LONG_HEADER_PACKET
                                       : GOOGLE_QUIC_PACKET,
       /*version_flag=*/true, early_arrived_packets.version,
@@ -1107,24 +1115,26 @@
   new_sessions_allowed_per_event_loop_ = max_connections_to_create;
   for (; new_sessions_allowed_per_event_loop_ > 0;
        --new_sessions_allowed_per_event_loop_) {
-    QuicConnectionId connection_id;
+    QuicConnectionId server_connection_id;
     BufferedPacketList packet_list =
-        buffered_packets_.DeliverPacketsForNextConnection(&connection_id);
+        buffered_packets_.DeliverPacketsForNextConnection(
+            &server_connection_id);
     const std::list<BufferedPacket>& packets = packet_list.buffered_packets;
     if (packets.empty()) {
       return;
     }
-    QuicConnectionId original_connection_id = connection_id;
-    connection_id =
-        MaybeReplaceConnectionId(connection_id, packet_list.version);
+    QuicConnectionId original_connection_id = server_connection_id;
+    server_connection_id = MaybeReplaceServerConnectionId(server_connection_id,
+                                                          packet_list.version);
     QuicSession* session =
-        CreateQuicSession(connection_id, packets.front().peer_address,
+        CreateQuicSession(server_connection_id, packets.front().peer_address,
                           packet_list.alpn, packet_list.version);
-    if (original_connection_id != connection_id) {
+    if (original_connection_id != server_connection_id) {
       session->connection()->AddIncomingConnectionId(original_connection_id);
     }
-    QUIC_DLOG(INFO) << "Created new session for " << connection_id;
-    session_map_.insert(std::make_pair(connection_id, QuicWrapUnique(session)));
+    QUIC_DLOG(INFO) << "Created new session for " << server_connection_id;
+    session_map_.insert(
+        std::make_pair(server_connection_id, QuicWrapUnique(session)));
     DeliverPacketsToSession(packets, session);
   }
 }
@@ -1134,21 +1144,23 @@
 }
 
 bool QuicDispatcher::ShouldCreateOrBufferPacketForConnection(
-    QuicConnectionId connection_id,
+    QuicConnectionId server_connection_id,
     bool ietf_quic) {
-  QUIC_VLOG(1) << "Received packet from new connection " << connection_id;
+  QUIC_VLOG(1) << "Received packet from new connection "
+               << server_connection_id;
   return true;
 }
 
 // Return true if there is any packet buffered in the store.
-bool QuicDispatcher::HasBufferedPackets(QuicConnectionId connection_id) {
-  return buffered_packets_.HasBufferedPackets(connection_id);
+bool QuicDispatcher::HasBufferedPackets(QuicConnectionId server_connection_id) {
+  return buffered_packets_.HasBufferedPackets(server_connection_id);
 }
 
-void QuicDispatcher::OnBufferPacketFailure(EnqueuePacketResult result,
-                                           QuicConnectionId connection_id) {
-  QUIC_DLOG(INFO) << "Fail to buffer packet on connection " << connection_id
-                  << " because of " << result;
+void QuicDispatcher::OnBufferPacketFailure(
+    EnqueuePacketResult result,
+    QuicConnectionId server_connection_id) {
+  QUIC_DLOG(INFO) << "Fail to buffer packet on connection "
+                  << server_connection_id << " because of " << result;
 }
 
 bool QuicDispatcher::ShouldAttemptCheapStatelessRejection() {
@@ -1160,21 +1172,22 @@
                                      alarm_factory_.get());
 }
 
-void QuicDispatcher::BufferEarlyPacket(QuicConnectionId connection_id,
+void QuicDispatcher::BufferEarlyPacket(QuicConnectionId server_connection_id,
                                        bool ietf_quic,
                                        ParsedQuicVersion version) {
-  bool is_new_connection = !buffered_packets_.HasBufferedPackets(connection_id);
-  if (is_new_connection &&
-      !ShouldCreateOrBufferPacketForConnection(connection_id, ietf_quic)) {
+  bool is_new_connection =
+      !buffered_packets_.HasBufferedPackets(server_connection_id);
+  if (is_new_connection && !ShouldCreateOrBufferPacketForConnection(
+                               server_connection_id, ietf_quic)) {
     return;
   }
 
   EnqueuePacketResult rs = buffered_packets_.EnqueuePacket(
-      connection_id, ietf_quic, *current_packet_, current_self_address_,
+      server_connection_id, ietf_quic, *current_packet_, current_self_address_,
       current_peer_address_, /*is_chlo=*/false,
       /*alpn=*/"", version);
   if (rs != EnqueuePacketResult::SUCCESS) {
-    OnBufferPacketFailure(rs, connection_id);
+    OnBufferPacketFailure(rs, server_connection_id);
   }
 }
 
@@ -1184,48 +1197,52 @@
     // Don't any create new connection.
     QUIC_CODE_COUNT(quic_reject_stop_accepting_new_connections);
     StatelesslyTerminateConnection(
-        current_connection_id(), form, /*version_flag=*/true, version,
+        current_server_connection_id(), form, /*version_flag=*/true, version,
         QUIC_HANDSHAKE_FAILED, "Stop accepting new connections",
         quic::QuicTimeWaitListManager::SEND_STATELESS_RESET);
     // Time wait list will reject the packet correspondingly.
     time_wait_list_manager()->ProcessPacket(
-        current_self_address(), current_peer_address(), current_connection_id(),
-        form, GetPerPacketContext());
+        current_self_address(), current_peer_address(),
+        current_server_connection_id(), form, GetPerPacketContext());
     return;
   }
-  if (!buffered_packets_.HasBufferedPackets(current_connection_id_) &&
-      !ShouldCreateOrBufferPacketForConnection(current_connection_id_,
+  if (!buffered_packets_.HasBufferedPackets(current_server_connection_id_) &&
+      !ShouldCreateOrBufferPacketForConnection(current_server_connection_id_,
                                                form != GOOGLE_QUIC_PACKET)) {
     return;
   }
   if (FLAGS_quic_allow_chlo_buffering &&
       new_sessions_allowed_per_event_loop_ <= 0) {
     // Can't create new session any more. Wait till next event loop.
-    QUIC_BUG_IF(buffered_packets_.HasChloForConnection(current_connection_id_));
+    QUIC_BUG_IF(
+        buffered_packets_.HasChloForConnection(current_server_connection_id_));
     EnqueuePacketResult rs = buffered_packets_.EnqueuePacket(
-        current_connection_id_, form != GOOGLE_QUIC_PACKET, *current_packet_,
-        current_self_address_, current_peer_address_,
+        current_server_connection_id_, form != GOOGLE_QUIC_PACKET,
+        *current_packet_, current_self_address_, current_peer_address_,
         /*is_chlo=*/true, current_alpn_, version);
     if (rs != EnqueuePacketResult::SUCCESS) {
-      OnBufferPacketFailure(rs, current_connection_id_);
+      OnBufferPacketFailure(rs, current_server_connection_id_);
     }
     return;
   }
 
-  QuicConnectionId original_connection_id = current_connection_id_;
-  current_connection_id_ =
-      MaybeReplaceConnectionId(current_connection_id_, version);
+  QuicConnectionId original_connection_id = current_server_connection_id_;
+  current_server_connection_id_ =
+      MaybeReplaceServerConnectionId(current_server_connection_id_, version);
   // Creates a new session and process all buffered packets for this connection.
-  QuicSession* session = CreateQuicSession(
-      current_connection_id_, current_peer_address_, current_alpn_, version);
-  if (original_connection_id != current_connection_id_) {
+  QuicSession* session =
+      CreateQuicSession(current_server_connection_id_, current_peer_address_,
+                        current_alpn_, version);
+  if (original_connection_id != current_server_connection_id_) {
     session->connection()->AddIncomingConnectionId(original_connection_id);
   }
-  QUIC_DLOG(INFO) << "Created new session for " << current_connection_id_;
+  QUIC_DLOG(INFO) << "Created new session for "
+                  << current_server_connection_id_;
   session_map_.insert(
-      std::make_pair(current_connection_id_, QuicWrapUnique(session)));
+      std::make_pair(current_server_connection_id_, QuicWrapUnique(session)));
   std::list<BufferedPacket> packets =
-      buffered_packets_.DeliverPackets(current_connection_id_).buffered_packets;
+      buffered_packets_.DeliverPackets(current_server_connection_id_)
+          .buffered_packets;
   // Process CHLO at first.
   session->ProcessUdpPacket(current_self_address_, current_peer_address_,
                             *current_packet_);
@@ -1295,12 +1312,13 @@
   bool current_version_flag_;
 };
 
-void QuicDispatcher::MaybeRejectStatelessly(QuicConnectionId connection_id,
-                                            PacketHeaderFormat form,
-                                            bool version_flag,
-                                            ParsedQuicVersion version) {
+void QuicDispatcher::MaybeRejectStatelessly(
+    QuicConnectionId server_connection_id,
+    PacketHeaderFormat form,
+    bool version_flag,
+    ParsedQuicVersion version) {
   if (version.handshake_protocol == PROTOCOL_TLS1_3) {
-    ProcessUnauthenticatedHeaderFate(kFateProcess, connection_id, form,
+    ProcessUnauthenticatedHeaderFate(kFateProcess, server_connection_id, form,
                                      version_flag, version);
     return;
     // TODO(nharper): Support buffering non-ClientHello packets when using TLS.
@@ -1315,14 +1333,15 @@
     if (FLAGS_quic_allow_chlo_buffering &&
         !ChloExtractor::Extract(*current_packet_, GetSupportedVersions(),
                                 config_->create_session_tag_indicators(),
-                                &alpn_extractor, connection_id.length())) {
+                                &alpn_extractor,
+                                server_connection_id.length())) {
       // Buffer non-CHLO packets.
-      ProcessUnauthenticatedHeaderFate(kFateBuffer, connection_id, form,
+      ProcessUnauthenticatedHeaderFate(kFateBuffer, server_connection_id, form,
                                        version_flag, version);
       return;
     }
     current_alpn_ = alpn_extractor.ConsumeAlpn();
-    ProcessUnauthenticatedHeaderFate(kFateProcess, connection_id, form,
+    ProcessUnauthenticatedHeaderFate(kFateProcess, server_connection_id, form,
                                      version_flag, version);
     return;
   }
@@ -1337,8 +1356,8 @@
                           rejector.get());
   if (!ChloExtractor::Extract(*current_packet_, GetSupportedVersions(),
                               config_->create_session_tag_indicators(),
-                              &validator, connection_id.length())) {
-    ProcessUnauthenticatedHeaderFate(kFateBuffer, connection_id, form,
+                              &validator, server_connection_id.length())) {
+    ProcessUnauthenticatedHeaderFate(kFateBuffer, server_connection_id, form,
                                      version_flag, version);
     return;
   }
@@ -1347,13 +1366,13 @@
   if (!validator.can_accept()) {
     // This CHLO is prohibited by policy.
     QUIC_CODE_COUNT(quic_reject_cant_accept_chlo);
-    StatelessConnectionTerminator terminator(connection_id, version, helper(),
-                                             time_wait_list_manager_.get());
+    StatelessConnectionTerminator terminator(
+        server_connection_id, version, helper(), time_wait_list_manager_.get());
     terminator.CloseConnection(QUIC_HANDSHAKE_FAILED, validator.error_details(),
                                form != GOOGLE_QUIC_PACKET);
     QuicSession::RecordConnectionCloseAtServer(
         QUIC_HANDSHAKE_FAILED, ConnectionCloseSource::FROM_SELF);
-    ProcessUnauthenticatedHeaderFate(kFateTimeWait, connection_id, form,
+    ProcessUnauthenticatedHeaderFate(kFateTimeWait, server_connection_id, form,
                                      version_flag, version);
     return;
   }
@@ -1368,10 +1387,10 @@
 
   // Insert into set of connection IDs to buffer
   const bool ok =
-      temporarily_buffered_connections_.insert(connection_id).second;
+      temporarily_buffered_connections_.insert(server_connection_id).second;
   QUIC_BUG_IF(!ok)
       << "Processing multiple stateless rejections for connection ID "
-      << connection_id;
+      << server_connection_id;
 
   // Continue stateless rejector processing
   std::unique_ptr<StatelessRejectorProcessDoneCallback> cb(
@@ -1395,7 +1414,7 @@
   current_peer_address_ = current_peer_address;
   current_self_address_ = current_self_address;
   current_packet_ = current_packet.get();
-  current_connection_id_ = rejector->connection_id();
+  current_server_connection_id_ = rejector->connection_id();
   if (!no_framer_) {
     framer_.set_version(first_version);
   }
diff --git a/quic/core/quic_dispatcher.h b/quic/core/quic_dispatcher.h
index 6adf5f3..1798a0d 100644
--- a/quic/core/quic_dispatcher.h
+++ b/quic/core/quic_dispatcher.h
@@ -76,7 +76,7 @@
   // QuicSession::Visitor interface implementation (via inheritance of
   // QuicTimeWaitListManager::Visitor):
   // Ensure that the closed connection is cleaned up asynchronously.
-  void OnConnectionClosed(QuicConnectionId connection_id,
+  void OnConnectionClosed(QuicConnectionId server_connection_id,
                           QuicErrorCode error,
                           const std::string& error_details,
                           ConnectionCloseSource source) override;
@@ -99,7 +99,8 @@
   // QuicTimeWaitListManager::Visitor interface implementation
   // Called whenever the time wait list manager adds a new connection to the
   // time-wait list.
-  void OnConnectionAddedToTimeWaitList(QuicConnectionId connection_id) override;
+  void OnConnectionAddedToTimeWaitList(
+      QuicConnectionId server_connection_id) override;
 
   using SessionMap = QuicUnorderedMap<QuicConnectionId,
                                       std::unique_ptr<QuicSession>,
@@ -191,7 +192,7 @@
       const QuicIetfStatelessResetPacket& packet) override;
 
   // QuicBufferedPacketStore::VisitorInterface implementation.
-  void OnExpiredPackets(QuicConnectionId connection_id,
+  void OnExpiredPackets(QuicConnectionId server_connection_id,
                         QuicBufferedPacketStore::BufferedPacketList
                             early_arrived_packets) override;
 
@@ -202,7 +203,7 @@
   virtual bool HasChlosBuffered() const;
 
  protected:
-  virtual QuicSession* CreateQuicSession(QuicConnectionId connection_id,
+  virtual QuicSession* CreateQuicSession(QuicConnectionId server_connection_id,
                                          const QuicSocketAddress& peer_address,
                                          QuicStringPiece alpn,
                                          const ParsedQuicVersion& version) = 0;
@@ -238,9 +239,9 @@
   // will be owned by the dispatcher as time_wait_list_manager_
   virtual QuicTimeWaitListManager* CreateQuicTimeWaitListManager();
 
-  // Called when |connection_id| doesn't have an open connection yet, to buffer
-  // |current_packet_| until it can be delivered to the connection.
-  void BufferEarlyPacket(QuicConnectionId connection_id,
+  // Called when |server_connection_id| doesn't have an open connection yet,
+  // to buffer |current_packet_| until it can be delivered to the connection.
+  void BufferEarlyPacket(QuicConnectionId server_connection_id,
                          bool ietf_quic,
                          ParsedQuicVersion version);
 
@@ -269,8 +270,8 @@
 
   const ParsedQuicVersionVector& GetSupportedVersions();
 
-  QuicConnectionId current_connection_id() const {
-    return current_connection_id_;
+  QuicConnectionId current_server_connection_id() const {
+    return current_server_connection_id_;
   }
   const QuicSocketAddress& current_self_address() const {
     return current_self_address_;
@@ -319,15 +320,15 @@
   // for CHLO. Returns true if a new connection should be created or its packets
   // should be buffered, false otherwise.
   virtual bool ShouldCreateOrBufferPacketForConnection(
-      QuicConnectionId connection_id,
+      QuicConnectionId server_connection_id,
       bool ietf_quic);
 
-  bool HasBufferedPackets(QuicConnectionId connection_id);
+  bool HasBufferedPackets(QuicConnectionId server_connection_id);
 
   // Called when BufferEarlyPacket() fail to buffer the packet.
   virtual void OnBufferPacketFailure(
       QuicBufferedPacketStore::EnqueuePacketResult result,
-      QuicConnectionId connection_id);
+      QuicConnectionId server_connection_id);
 
   // Removes the session from the session map and write blocked list, and adds
   // the ConnectionId to the time-wait list.  If |session_closed_statelessly| is
@@ -344,7 +345,7 @@
   // connection to time wait list or 2) directly add connection to time wait
   // list with |action|.
   void StatelesslyTerminateConnection(
-      QuicConnectionId connection_id,
+      QuicConnectionId server_connection_id,
       PacketHeaderFormat format,
       bool version_flag,
       ParsedQuicVersion version,
@@ -374,10 +375,11 @@
   }
 
   // If true, the dispatcher will allow incoming initial packets that have
-  // connection IDs shorter than 64 bits.
-  void SetAllowShortInitialConnectionIds(
-      bool allow_short_initial_connection_ids) {
-    allow_short_initial_connection_ids_ = allow_short_initial_connection_ids;
+  // destination connection IDs shorter than 64 bits.
+  void SetAllowShortInitialServerConnectionIds(
+      bool allow_short_initial_server_connection_ids) {
+    allow_short_initial_server_connection_ids_ =
+        allow_short_initial_server_connection_ids;
   }
 
  private:
@@ -395,7 +397,7 @@
   // possible and if the current packet contains a CHLO message.  Determines a
   // fate which describes what subsequent processing should be performed on the
   // packets, like ValidityChecks, and invokes ProcessUnauthenticatedHeaderFate.
-  void MaybeRejectStatelessly(QuicConnectionId connection_id,
+  void MaybeRejectStatelessly(QuicConnectionId server_connection_id,
                               PacketHeaderFormat form,
                               bool version_flag,
                               ParsedQuicVersion version);
@@ -408,7 +410,7 @@
   // Perform the appropriate actions on the current packet based on |fate| -
   // either process, buffer, or drop it.
   void ProcessUnauthenticatedHeaderFate(QuicPacketFate fate,
-                                        QuicConnectionId connection_id,
+                                        QuicConnectionId server_connection_id,
                                         PacketHeaderFormat form,
                                         bool version_flag,
                                         ParsedQuicVersion version);
@@ -440,8 +442,9 @@
   // If the connection ID length is different from what the dispatcher expects,
   // replace the connection ID with a random one of the right length,
   // and save it to make sure the mapping is persistent.
-  QuicConnectionId MaybeReplaceConnectionId(QuicConnectionId connection_id,
-                                            ParsedQuicVersion version);
+  QuicConnectionId MaybeReplaceServerConnectionId(
+      QuicConnectionId server_connection_id,
+      ParsedQuicVersion version);
 
   // Returns true if |version| is a supported protocol version.
   bool IsSupportedVersion(const ParsedQuicVersion version);
@@ -505,7 +508,7 @@
   const QuicReceivedPacket* current_packet_;
   // If |current_packet_| is a CHLO packet, the extracted alpn.
   std::string current_alpn_;
-  QuicConnectionId current_connection_id_;
+  QuicConnectionId current_server_connection_id_;
 
   // Used to get the supported versions based on flag. Does not own.
   QuicVersionManager* version_manager_;
@@ -524,8 +527,9 @@
   bool accept_new_connections_;
 
   // If false, the dispatcher follows the IETF spec and rejects packets with
-  // invalid connection IDs lengths below 64 bits. If true they are allowed.
-  bool allow_short_initial_connection_ids_;
+  // invalid destination connection IDs lengths below 64 bits.
+  // If true they are allowed.
+  bool allow_short_initial_server_connection_ids_;
 
   // The last QUIC version label received. Used when no_framer_ is true.
   // TODO(fayang): remove this member variable, instead, add an argument to
diff --git a/quic/core/quic_dispatcher_test.cc b/quic/core/quic_dispatcher_test.cc
index 46c5bc2..de06c52 100644
--- a/quic/core/quic_dispatcher_test.cc
+++ b/quic/core/quic_dispatcher_test.cc
@@ -156,7 +156,7 @@
   using QuicDispatcher::current_client_address;
   using QuicDispatcher::current_peer_address;
   using QuicDispatcher::current_self_address;
-  using QuicDispatcher::SetAllowShortInitialConnectionIds;
+  using QuicDispatcher::SetAllowShortInitialServerConnectionIds;
   using QuicDispatcher::writer;
 };
 
@@ -686,7 +686,7 @@
       QuicUtils::CreateRandomConnectionId(mock_helper_.GetRandomGenerator());
 
   // Disable validation of invalid short connection IDs.
-  dispatcher_->SetAllowShortInitialConnectionIds(true);
+  dispatcher_->SetAllowShortInitialServerConnectionIds(true);
   // Note that StrayPacketTruncatedConnectionId covers the case where the
   // validation is still enabled.
 
diff --git a/quic/core/quic_framer.cc b/quic/core/quic_framer.cc
index 27af834..eff8f49 100644
--- a/quic/core/quic_framer.cc
+++ b/quic/core/quic_framer.cc
@@ -462,7 +462,7 @@
                        uint8_t expected_connection_id_length)
     : visitor_(nullptr),
       error_(QUIC_NO_ERROR),
-      last_serialized_connection_id_(EmptyQuicConnectionId()),
+      last_serialized_server_connection_id_(EmptyQuicConnectionId()),
       last_version_label_(0),
       version_(PROTOCOL_UNSUPPORTED, QUIC_VERSION_UNSUPPORTED),
       supported_versions_(supported_versions),
@@ -1427,13 +1427,13 @@
 // static
 std::unique_ptr<QuicEncryptedPacket>
 QuicFramer::BuildIetfVersionNegotiationPacket(
-    QuicConnectionId connection_id,
+    QuicConnectionId source_connection_id,
     const ParsedQuicVersionVector& versions) {
   QUIC_DVLOG(1) << "Building IETF version negotiation packet: "
                 << ParsedQuicVersionVectorToString(versions);
   DCHECK(!versions.empty());
   size_t len = kPacketHeaderTypeSize + kConnectionIdLengthSize +
-               connection_id.length() +
+               source_connection_id.length() +
                (versions.size() + 1) * kQuicVersionSize;
   std::unique_ptr<char[]> buffer(new char[len]);
   QuicDataWriter writer(len, buffer.get());
@@ -1452,8 +1452,8 @@
     return nullptr;
   }
 
-  if (!AppendIetfConnectionIds(true, EmptyQuicConnectionId(), connection_id,
-                               &writer)) {
+  if (!AppendIetfConnectionIds(true, EmptyQuicConnectionId(),
+                               source_connection_id, &writer)) {
     return nullptr;
   }
 
@@ -2064,14 +2064,14 @@
     public_flags |= PACKET_PUBLIC_FLAGS_NONCE;
   }
 
-  QuicConnectionId connection_id =
+  QuicConnectionId server_connection_id =
       GetServerConnectionIdAsSender(header, perspective_);
-  QuicConnectionIdIncluded connection_id_included =
+  QuicConnectionIdIncluded server_connection_id_included =
       GetServerConnectionIdIncludedAsSender(header, perspective_);
   DCHECK_EQ(CONNECTION_ID_ABSENT,
             GetClientConnectionIdIncludedAsSender(header, perspective_));
 
-  switch (connection_id_included) {
+  switch (server_connection_id_included) {
     case CONNECTION_ID_ABSENT:
       if (!writer->WriteUInt8(public_flags |
                               PACKET_PUBLIC_FLAGS_0BYTE_CONNECTION_ID)) {
@@ -2080,9 +2080,9 @@
       break;
     case CONNECTION_ID_PRESENT:
       QUIC_BUG_IF(!QuicUtils::IsConnectionIdValidForVersion(
-          connection_id, transport_version()))
+          server_connection_id, transport_version()))
           << "AppendPacketHeader: attempted to use connection ID "
-          << connection_id << " which is invalid with version "
+          << server_connection_id << " which is invalid with version "
           << QuicVersionToString(transport_version());
 
       public_flags |= PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID;
@@ -2090,12 +2090,12 @@
         public_flags |= PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID_OLD;
       }
       if (!writer->WriteUInt8(public_flags) ||
-          !writer->WriteConnectionId(connection_id)) {
+          !writer->WriteConnectionId(server_connection_id)) {
         return false;
       }
       break;
   }
-  last_serialized_connection_id_ = connection_id;
+  last_serialized_server_connection_id_ = server_connection_id;
 
   if (header.version_flag) {
     DCHECK_EQ(Perspective::IS_CLIENT, perspective_);
@@ -2194,7 +2194,7 @@
     return false;
   }
 
-  last_serialized_connection_id_ = server_connection_id;
+  last_serialized_server_connection_id_ = server_connection_id;
 
   if (QuicVersionHasLongHeaderLengths(transport_version()) &&
       header.version_flag) {
@@ -2336,7 +2336,7 @@
       break;
     case PACKET_PUBLIC_FLAGS_0BYTE_CONNECTION_ID:
       *header_connection_id_included = CONNECTION_ID_ABSENT;
-      *header_connection_id = last_serialized_connection_id_;
+      *header_connection_id = last_serialized_server_connection_id_;
       break;
   }
 
@@ -2709,13 +2709,13 @@
       header->destination_connection_id = header->source_connection_id;
     } else if (header->destination_connection_id_included ==
                CONNECTION_ID_ABSENT) {
-      header->destination_connection_id = last_serialized_connection_id_;
+      header->destination_connection_id = last_serialized_server_connection_id_;
     }
   } else {
     QUIC_RESTART_FLAG_COUNT_N(quic_do_not_override_connection_id, 5, 5);
     if (header->source_connection_id_included == CONNECTION_ID_ABSENT) {
       DCHECK_EQ(EmptyQuicConnectionId(), header->source_connection_id);
-      header->source_connection_id = last_serialized_connection_id_;
+      header->source_connection_id = last_serialized_server_connection_id_;
     }
   }
 
diff --git a/quic/core/quic_framer.h b/quic/core/quic_framer.h
index ab0e8d7..e56aba2 100644
--- a/quic/core/quic_framer.h
+++ b/quic/core/quic_framer.h
@@ -441,7 +441,7 @@
 
   // Returns a new IETF version negotiation packet.
   static std::unique_ptr<QuicEncryptedPacket> BuildIetfVersionNegotiationPacket(
-      QuicConnectionId connection_id,
+      QuicConnectionId source_connection_id,
       const ParsedQuicVersionVector& versions);
 
   // If header.version_flag is set, the version in the
@@ -958,8 +958,8 @@
   // Largest successfully decrypted packet number per packet number space. Only
   // used when supports_multiple_packet_number_spaces_ is true.
   QuicPacketNumber largest_decrypted_packet_numbers_[NUM_PACKET_NUMBER_SPACES];
-  // Updated by WritePacketHeader.
-  QuicConnectionId last_serialized_connection_id_;
+  // Last server connection ID seen on the wire.
+  QuicConnectionId last_serialized_server_connection_id_;
   // The last QUIC version label received.
   // TODO(fayang): Remove this when deprecating
   // quic_no_framer_object_in_dispatcher.
diff --git a/quic/core/quic_framer_test.cc b/quic/core/quic_framer_test.cc
index bf87ace..85af7ea 100644
--- a/quic/core/quic_framer_test.cc
+++ b/quic/core/quic_framer_test.cc
@@ -1011,8 +1011,8 @@
 
 TEST_P(QuicFramerTest, PacketHeaderWith0ByteConnectionId) {
   SetDecrypterLevel(ENCRYPTION_FORWARD_SECURE);
-  QuicFramerPeer::SetLastSerializedConnectionId(&framer_,
-                                                FramerTestConnectionId());
+  QuicFramerPeer::SetLastSerializedServerConnectionId(&framer_,
+                                                      FramerTestConnectionId());
   QuicFramerPeer::SetPerspective(&framer_, Perspective::IS_CLIENT);
 
   // clang-format off
diff --git a/quic/core/quic_packet_creator.cc b/quic/core/quic_packet_creator.cc
index c013ce8..77b5971 100644
--- a/quic/core/quic_packet_creator.cc
+++ b/quic/core/quic_packet_creator.cc
@@ -53,15 +53,15 @@
 #define ENDPOINT \
   (framer_->perspective() == Perspective::IS_SERVER ? "Server: " : "Client: ")
 
-QuicPacketCreator::QuicPacketCreator(QuicConnectionId connection_id,
+QuicPacketCreator::QuicPacketCreator(QuicConnectionId server_connection_id,
                                      QuicFramer* framer,
                                      DelegateInterface* delegate)
-    : QuicPacketCreator(connection_id,
+    : QuicPacketCreator(server_connection_id,
                         framer,
                         QuicRandom::GetInstance(),
                         delegate) {}
 
-QuicPacketCreator::QuicPacketCreator(QuicConnectionId connection_id,
+QuicPacketCreator::QuicPacketCreator(QuicConnectionId server_connection_id,
                                      QuicFramer* framer,
                                      QuicRandom* random,
                                      DelegateInterface* delegate)
@@ -72,9 +72,9 @@
       send_version_in_packet_(framer->perspective() == Perspective::IS_CLIENT),
       have_diversification_nonce_(false),
       max_packet_length_(0),
-      connection_id_included_(CONNECTION_ID_PRESENT),
+      server_connection_id_included_(CONNECTION_ID_PRESENT),
       packet_size_(0),
-      connection_id_(connection_id),
+      server_connection_id_(server_connection_id),
       packet_(QuicPacketNumber(),
               PACKET_1BYTE_PACKET_NUMBER,
               nullptr,
@@ -626,8 +626,8 @@
     const ParsedQuicVersionVector& supported_versions) {
   DCHECK_EQ(Perspective::IS_SERVER, framer_->perspective());
   std::unique_ptr<QuicEncryptedPacket> encrypted =
-      QuicFramer::BuildVersionNegotiationPacket(connection_id_, ietf_quic,
-                                                supported_versions);
+      QuicFramer::BuildVersionNegotiationPacket(server_connection_id_,
+                                                ietf_quic, supported_versions);
   DCHECK(encrypted);
   DCHECK_GE(max_packet_length_, encrypted->length());
   return encrypted;
@@ -737,24 +737,24 @@
 
 QuicConnectionId QuicPacketCreator::GetDestinationConnectionId() const {
   if (!GetQuicRestartFlag(quic_do_not_override_connection_id)) {
-    return connection_id_;
+    return server_connection_id_;
   }
   QUIC_RESTART_FLAG_COUNT_N(quic_do_not_override_connection_id, 1, 5);
   if (framer_->perspective() == Perspective::IS_SERVER) {
     return EmptyQuicConnectionId();
   }
-  return connection_id_;
+  return server_connection_id_;
 }
 
 QuicConnectionId QuicPacketCreator::GetSourceConnectionId() const {
   if (!GetQuicRestartFlag(quic_do_not_override_connection_id)) {
-    return connection_id_;
+    return server_connection_id_;
   }
   QUIC_RESTART_FLAG_COUNT_N(quic_do_not_override_connection_id, 6, 6);
   if (framer_->perspective() == Perspective::IS_CLIENT) {
     return EmptyQuicConnectionId();
   }
-  return connection_id_;
+  return server_connection_id_;
 }
 
 QuicConnectionIdIncluded QuicPacketCreator::GetDestinationConnectionIdIncluded()
@@ -767,7 +767,7 @@
                ? CONNECTION_ID_PRESENT
                : CONNECTION_ID_ABSENT;
   }
-  return connection_id_included_;
+  return server_connection_id_included_;
 }
 
 QuicConnectionIdIncluded QuicPacketCreator::GetSourceConnectionIdIncluded()
@@ -779,14 +779,14 @@
   if (GetQuicRestartFlag(quic_do_not_override_connection_id) &&
       framer_->perspective() == Perspective::IS_SERVER) {
     QUIC_RESTART_FLAG_COUNT_N(quic_do_not_override_connection_id, 2, 5);
-    return connection_id_included_;
+    return server_connection_id_included_;
   }
   return CONNECTION_ID_ABSENT;
 }
 
 QuicConnectionIdLength QuicPacketCreator::GetDestinationConnectionIdLength()
     const {
-  DCHECK(QuicUtils::IsConnectionIdValidForVersion(connection_id_,
+  DCHECK(QuicUtils::IsConnectionIdValidForVersion(server_connection_id_,
                                                   transport_version()));
   return GetDestinationConnectionIdIncluded() == CONNECTION_ID_PRESENT
              ? static_cast<QuicConnectionIdLength>(
@@ -795,7 +795,7 @@
 }
 
 QuicConnectionIdLength QuicPacketCreator::GetSourceConnectionIdLength() const {
-  DCHECK(QuicUtils::IsConnectionIdValidForVersion(connection_id_,
+  DCHECK(QuicUtils::IsConnectionIdValidForVersion(server_connection_id_,
                                                   transport_version()));
   return GetSourceConnectionIdIncluded() == CONNECTION_ID_PRESENT
              ? static_cast<QuicConnectionIdLength>(
@@ -1019,17 +1019,18 @@
   return packet_.encryption_level == ENCRYPTION_INITIAL;
 }
 
-void QuicPacketCreator::SetConnectionIdIncluded(
-    QuicConnectionIdIncluded connection_id_included) {
-  DCHECK(connection_id_included == CONNECTION_ID_PRESENT ||
-         connection_id_included == CONNECTION_ID_ABSENT);
+void QuicPacketCreator::SetServerConnectionIdIncluded(
+    QuicConnectionIdIncluded server_connection_id_included) {
+  DCHECK(server_connection_id_included == CONNECTION_ID_PRESENT ||
+         server_connection_id_included == CONNECTION_ID_ABSENT);
   DCHECK(framer_->perspective() == Perspective::IS_SERVER ||
-         connection_id_included != CONNECTION_ID_ABSENT);
-  connection_id_included_ = connection_id_included;
+         server_connection_id_included != CONNECTION_ID_ABSENT);
+  server_connection_id_included_ = server_connection_id_included;
 }
 
-void QuicPacketCreator::SetConnectionId(QuicConnectionId connection_id) {
-  connection_id_ = connection_id;
+void QuicPacketCreator::SetServerConnectionId(
+    QuicConnectionId server_connection_id) {
+  server_connection_id_ = server_connection_id;
 }
 
 void QuicPacketCreator::SetTransmissionType(TransmissionType type) {
diff --git a/quic/core/quic_packet_creator.h b/quic/core/quic_packet_creator.h
index 6e1f7a2..259b577 100644
--- a/quic/core/quic_packet_creator.h
+++ b/quic/core/quic_packet_creator.h
@@ -56,10 +56,10 @@
     virtual void OnFrameAddedToPacket(const QuicFrame& frame) {}
   };
 
-  QuicPacketCreator(QuicConnectionId connection_id,
+  QuicPacketCreator(QuicConnectionId server_connection_id,
                     QuicFramer* framer,
                     DelegateInterface* delegate);
-  QuicPacketCreator(QuicConnectionId connection_id,
+  QuicPacketCreator(QuicConnectionId server_connection_id,
                     QuicFramer* framer,
                     QuicRandom* random,
                     DelegateInterface* delegate);
@@ -222,11 +222,12 @@
   // Returns length of source connection ID to send over the wire.
   QuicConnectionIdLength GetSourceConnectionIdLength() const;
 
-  // Sets whether the connection ID should be sent over the wire.
-  void SetConnectionIdIncluded(QuicConnectionIdIncluded connection_id_included);
+  // Sets whether the server connection ID should be sent over the wire.
+  void SetServerConnectionIdIncluded(
+      QuicConnectionIdIncluded server_connection_id_included);
 
   // Update the connection ID used in outgoing packets.
-  void SetConnectionId(QuicConnectionId connection_id);
+  void SetServerConnectionId(QuicConnectionId server_connection_id);
 
   // Sets the encryption level that will be applied to new packets.
   void set_encryption_level(EncryptionLevel level) {
@@ -393,8 +394,8 @@
   // Maximum length including headers and encryption (UDP payload length.)
   QuicByteCount max_packet_length_;
   size_t max_plaintext_size_;
-  // Whether the connection_id is sent over the wire.
-  QuicConnectionIdIncluded connection_id_included_;
+  // Whether the server_connection_id is sent over the wire.
+  QuicConnectionIdIncluded server_connection_id_included_;
 
   // Frames to be added to the next SerializedPacket
   QuicFrames queued_frames_;
@@ -403,7 +404,7 @@
   // TODO(ianswett): Move packet_size_ into SerializedPacket once
   // QuicEncryptedPacket has been flattened into SerializedPacket.
   size_t packet_size_;
-  QuicConnectionId connection_id_;
+  QuicConnectionId server_connection_id_;
 
   // Packet used to invoke OnSerializedPacket.
   SerializedPacket packet_;
diff --git a/quic/core/quic_packet_generator.cc b/quic/core/quic_packet_generator.cc
index d811f9d..f490900 100644
--- a/quic/core/quic_packet_generator.cc
+++ b/quic/core/quic_packet_generator.cc
@@ -17,12 +17,12 @@
 
 namespace quic {
 
-QuicPacketGenerator::QuicPacketGenerator(QuicConnectionId connection_id,
+QuicPacketGenerator::QuicPacketGenerator(QuicConnectionId server_connection_id,
                                          QuicFramer* framer,
                                          QuicRandom* random_generator,
                                          DelegateInterface* delegate)
     : delegate_(delegate),
-      packet_creator_(connection_id, framer, random_generator, delegate),
+      packet_creator_(server_connection_id, framer, random_generator, delegate),
       next_transmission_type_(NOT_RETRANSMISSION),
       flusher_attached_(false),
       should_send_ack_(false),
@@ -438,11 +438,11 @@
                                                   max_packets_in_flight);
 }
 
-void QuicPacketGenerator::SetConnectionIdLength(uint32_t length) {
+void QuicPacketGenerator::SetServerConnectionIdLength(uint32_t length) {
   if (length == 0) {
-    packet_creator_.SetConnectionIdIncluded(CONNECTION_ID_ABSENT);
+    packet_creator_.SetServerConnectionIdIncluded(CONNECTION_ID_ABSENT);
   } else {
-    packet_creator_.SetConnectionIdIncluded(CONNECTION_ID_PRESENT);
+    packet_creator_.SetServerConnectionIdIncluded(CONNECTION_ID_PRESENT);
   }
 }
 
@@ -569,8 +569,9 @@
   return packet_creator_.GetGuaranteedLargestMessagePayload();
 }
 
-void QuicPacketGenerator::SetConnectionId(QuicConnectionId connection_id) {
-  packet_creator_.SetConnectionId(connection_id);
+void QuicPacketGenerator::SetServerConnectionId(
+    QuicConnectionId server_connection_id) {
+  packet_creator_.SetServerConnectionId(server_connection_id);
 }
 
 }  // namespace quic
diff --git a/quic/core/quic_packet_generator.h b/quic/core/quic_packet_generator.h
index 417fda6..6ea8215 100644
--- a/quic/core/quic_packet_generator.h
+++ b/quic/core/quic_packet_generator.h
@@ -76,7 +76,7 @@
         QuicStopWaitingFrame* stop_waiting) = 0;
   };
 
-  QuicPacketGenerator(QuicConnectionId connection_id,
+  QuicPacketGenerator(QuicConnectionId server_connection_id,
                       QuicFramer* framer,
                       QuicRandom* random_generator,
                       DelegateInterface* delegate);
@@ -185,8 +185,8 @@
   void UpdatePacketNumberLength(QuicPacketNumber least_packet_awaited_by_peer,
                                 QuicPacketCount max_packets_in_flight);
 
-  // Set the minimum number of bytes for the connection id length;
-  void SetConnectionIdLength(uint32_t length);
+  // Set the minimum number of bytes for the server connection id length;
+  void SetServerConnectionIdLength(uint32_t length);
 
   // Sets the encrypter to use for the encryption level.
   void SetEncrypter(EncryptionLevel level,
@@ -235,8 +235,8 @@
   QuicPacketLength GetCurrentLargestMessagePayload() const;
   QuicPacketLength GetGuaranteedLargestMessagePayload() const;
 
-  // Update the connection ID used in outgoing packets.
-  void SetConnectionId(QuicConnectionId connection_id);
+  // Update the server connection ID used in outgoing packets.
+  void SetServerConnectionId(QuicConnectionId server_connection_id);
 
   void set_debug_delegate(QuicPacketCreator::DebugDelegate* debug_delegate) {
     packet_creator_.set_debug_delegate(debug_delegate);
diff --git a/quic/core/quic_packet_generator_test.cc b/quic/core/quic_packet_generator_test.cc
index 676d6e7..e1899ff 100644
--- a/quic/core/quic_packet_generator_test.cc
+++ b/quic/core/quic_packet_generator_test.cc
@@ -1139,12 +1139,12 @@
 
 TEST_F(QuicPacketGeneratorTest, TestConnectionIdLength) {
   QuicFramerPeer::SetPerspective(&framer_, Perspective::IS_SERVER);
-  generator_.SetConnectionIdLength(0);
+  generator_.SetServerConnectionIdLength(0);
   EXPECT_EQ(PACKET_0BYTE_CONNECTION_ID,
             creator_->GetDestinationConnectionIdLength());
 
   for (size_t i = 1; i < 10; i++) {
-    generator_.SetConnectionIdLength(i);
+    generator_.SetServerConnectionIdLength(i);
     if (framer_.transport_version() > QUIC_VERSION_43) {
       EXPECT_EQ(PACKET_0BYTE_CONNECTION_ID,
                 creator_->GetDestinationConnectionIdLength());
diff --git a/quic/core/quic_session.h b/quic/core/quic_session.h
index d8f40c9..dc7153a 100644
--- a/quic/core/quic_session.h
+++ b/quic/core/quic_session.h
@@ -52,7 +52,7 @@
     virtual ~Visitor() {}
 
     // Called when the connection is closed after the streams have been closed.
-    virtual void OnConnectionClosed(QuicConnectionId connection_id,
+    virtual void OnConnectionClosed(QuicConnectionId server_connection_id,
                                     QuicErrorCode error,
                                     const std::string& error_details,
                                     ConnectionCloseSource source) = 0;