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

ianswett <notifications@github.com> Mon, 23 September 2019 15:22 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.



> @@ -526,12 +526,11 @@ as a probe, unless there is no data available to send.  An endpoint MAY send up
 to two full-sized datagrams containing ack-eliciting packets, to avoid an
 expensive consecutive PTO expiration due to a single lost datagram.
 
-It is possible that 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.  In the absence of any new
-application data, a PTO timer expiration now would find the sender with no new
-or previously-sent data to send.
+When the PTO timer expires, and there is new or previously sent data, it MUST
+be sent.  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.

This is a fairly common case in our implementation, so I think it's a good example.

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