diff --git a/quiche/quic/core/quic_framer.cc b/quiche/quic/core/quic_framer.cc
index 32a54dd..1cddd90 100644
--- a/quiche/quic/core/quic_framer.cc
+++ b/quiche/quic/core/quic_framer.cc
@@ -316,8 +316,8 @@
 }
 
 bool AppendIetfConnectionIds(bool version_flag, bool use_length_prefix,
-                             QuicConnectionId destination_connection_id,
-                             QuicConnectionId source_connection_id,
+                             const QuicConnectionId& destination_connection_id,
+                             const QuicConnectionId& source_connection_id,
                              QuicDataWriter* writer) {
   if (!version_flag) {
     return writer->WriteConnectionId(destination_connection_id);