Original text:
4.7. QUIC uses a probe timeout (PTO; see pto), with a timer based on TCP's <del> RTO computation.  QUIC's PTO includes the peer's maximum expected acknowledgment delay instead of using a fixed minimum timeout.  QUIC does not collapse the congestion window until persistent congestion (persistent-congestion) is declared, unlike TCP, which collapses the congestion window upon expiry of an RTO.  Instead of collapsing the congestion window and declaring everything in-flight lost, QUIC allows probe packets to temporarily exceed the congestion window whenever the timer expires. In doing this, QUIC avoids unnecessary congestion window reductions, </del>  obviating the need for correcting mechanisms such as F-RTO (RFC5682). Since QUIC does not collapse the congestion window on a PTO expiration, a QUIC sender is not limited from sending more in-flight timer expires.  This is more aggressive than TCP's RTO mechanism when application-limited, but identical when not application-limited. <del> A single packet loss at the tail does not indicate persistent congestion, so QUIC specifies a time-based definition to ensure one or more packets are sent prior to a dramatic decrease in congestion window; see persistent-congestion. </del>  4.8. Acknowledgment-based loss detection implements the spirit of TCP's Fast Retransmit (RFC5681), Early Retransmit (RFC5827), FACK (FACK), <del> SACK loss recovery (RFC6675), and RACK (RACK).  This section provides an overview of how these algorithms are implemented in QUIC. </del>  A packet is declared lost if it meets all the following conditions:

Reviewer comments:
and part of
Alissa Cooper said:
NAME said:
Good point, also 4.7 currently has TLP in the title, but doesn't use it anywhere else in the section, so I'll add some text on TLP too. URL
Please also update the RACK reference to version 14. draft-ietf-tcpm-rack-14
The version update is part of the toolchain we use, so the newest version of RACK should be referenced automatically.

Revised text:
4.7. QUIC uses a probe timeout (PTO; see pto), with a timer based on TCP's  <ins> RTO computation; see RFC6297.  QUIC's PTO includes the peer's maximum expected acknowledgment delay instead of using a fixed minimum timeout. Similar to the RACK-TLP loss detection algorithm for TCP (RACK), QUIC does not collapse the congestion window when the PTO expires, since a single packet loss at the tail does not indicate persistent congestion.  Instead, QUIC collapses the congestion window when persistent congestion is declared; see persistent-congestion.  In doing this, QUIC avoids unnecessary congestion window reductions, </ins> obviating the need for correcting mechanisms such as F-RTO (RFC5682). Since QUIC does not collapse the congestion window on a PTO expiration, a QUIC sender is not limited from sending more in-flight timer expires.  This is more aggressive than TCP's RTO mechanism when application-limited, but identical when not application-limited.  <ins> QUIC allows probe packets to temporarily exceed the congestion window whenever the timer expires. </ins> 4.8. Acknowledgment-based loss detection implements the spirit of TCP's Fast Retransmit (RFC5681), Early Retransmit (RFC5827), FACK (FACK),  <ins> SACK loss recovery (RFC6675), and RACK-TLP (RACK).  This section provides an overview of how these algorithms are implemented in QUIC. </ins> A packet is declared lost if it meets all the following conditions: