Default enable PTO with configuration:
1) Send 1 packet per PTO with skipped packet number.
2) Arm the 1st PTO based on the earliest in flight sent time while making sure at least 1.5 * srtt has passed since the last in flight packet.
3) PTO delay = srtt + 2 * rttvar + ack_delay.

Please note, this should only affect gQUIC while IETF QUIC has been using PTO with this configuration.

Also cleanup experiment connection options: 2PTO, 1PTO, PTOS, PTOA, PEB1, PEB2, PVS1, PAG1, PAG2, PLE1, PLE2, APTO, PSDA.

Protected by FLAGS_quic_restart_flag_quic_default_on_pto2.

PiperOrigin-RevId: 431699930
4 files changed
tree: 8dbf86d8cdcadc287b7750d1c02b3744d94add35
  1. common/
  2. epoll_server/
  3. http2/
  4. quic/
  5. spdy/


QUICHE stands for QUIC, Http/2, Etc. It is Google‘s production-ready implementation of QUIC, HTTP/2, HTTP/3, and related protocols and tools. It powers Google’s servers, Chromium, Envoy, and other projects. It is actively developed and maintained.

There are two public QUICHE repositories. Either one may be used by embedders, as they are automatically kept in sync:

To embed QUICHE in your project, platform APIs need to be implemented and build files need to be created. Note that it is on the QUICHE team's roadmap to include default implementation for all platform APIs and to open-source build files. In the meanwhile, take a look at open source embedders like Chromium and Envoy to get started:

To contribute to QUICHE, follow instructions at

QUICHE is only supported on little-endian platforms.