Re: [quicwg/base-drafts] PTO MUST send new data or retransmit data if possible (#3057)

ianswett <notifications@github.com> Tue, 24 September 2019 01:18 UTC

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Subject: Re: [quicwg/base-drafts] PTO MUST send new data or retransmit data if possible (#3057)
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ianswett commented on this pull request.



>  
-When there is no data to send, the sender SHOULD send a PING or other
-ack-eliciting frame in a single packet, re-arming the PTO timer.
+It is possible the sender has no new or previously-sent data to send.
+As an example, consider the following sequence of events: new application data
+is sent in a STREAM frame, deemed lost, then retransmitted in a new packet,
+and then the original transmission is acknowledged.  When there is no data to
+send, the sender SHOULD send a PING or other ack-eliciting frame in a single
+packet, re-arming the PTO timer.

In this example, the point is that in order to remove the retransmission from byte in flight, you SHOULD send a PING and when it's acknowledged, you'll know whether the retransmission was lost or not.  Ideally it'll be ACKed on its own before the PTO fires.

The above text is about the server's amplification factor and not arming the alarm when "If no data can be sent"

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