quic mtu

QUIC requires to not have IP fragmentation. By looking at the source code, it seems that QUIC assumes a maximum of 1392:

• Ether=14
• IPv4=20
• UDP=8
• QUIC=1350

Is it a static configuration, or do you have some "tricks" during the "no encryption" initialization phase to change this value (increment or decrement) ?

https://chromium.googlesource.com/chromium/src/net/+/master/quic/quic_protocol.h

// Default and initial maximum size in bytes of a QUIC packet.
const QuicByteCount kDefaultMaxPacketSize = 1350;
// Default initial maximum size in bytes of a QUIC packet for servers.
const QuicByteCount kDefaultServerMaxPacketSize = 1000;
// The maximum packet size of any QUIC packet, based on ethernet's max size,
// minus the IP and UDP headers. IPv6 has a 40 byte header, UPD adds an
// additional 8 bytes.  This is a total overhead of 48 bytes.  Ethernet's
// max packet size is 1500 bytes,  1500 - 48 = 1452

https://chromium.googlesource.com/chromium/src/net/+/master/quic/quic_packet_creator.cc

QuicPacketCreator::QuicPacketCreator(QuicConnectionId connection_id,
                                     QuicFramer* framer,
                                     QuicRandom* random_generator)
...
{
  SetMaxPacketLength(kDefaultMaxPacketSize);
}