diff --git a/draft-ietf-quic-recovery.md b/draft-ietf-quic-recovery.md index 562d783c95..9effcf32c2 100644 --- a/draft-ietf-quic-recovery.md +++ b/draft-ietf-quic-recovery.md @@ -753,6 +753,12 @@ delivery of ACK frames is important for efficient loss recovery. Packets containing only ACK frames should therefore not be paced, to avoid delaying their delivery to the peer. +Sending multiple packets into the network without any delay between them +creates a packet burst that might cause short-term congestion and losses. +Implementations MUST either use pacing or limit such bursts to minimum +of 10 * kMaxDatagramSize and max(2* kMaxDatagramSize, 14720)), the same +as the recommended initial congestion window. + As an example of a well-known and publicly available implementation of a flow pacer, implementers are referred to the Fair Queue packet scheduler (fq qdisc) in Linux (3.11 onwards). @@ -773,13 +779,6 @@ and not fully utilize the congestion window due to this delay. A sender should not consider itself application limited if it would have fully utilized the congestion window without pacing delay. -Sending multiple packets into the network without any delay between them -creates a packet burst that might cause short-term congestion and losses. -Implementations SHOULD either use pacing or reduce their congestion window -to limit such bursts to minimum of 10 * kMaxDatagramSize and -max(2* kMaxDatagramSize, 14720)), the same as the recommended initial -congestion window. - A sender MAY implement alternative mechanisms to update its congestion window after periods of under-utilization, such as those proposed for TCP in {{?RFC7661}}.