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Re: [quicwg/base-drafts] loss of only two packets can lead to an unrecoverable situation (#2267)

Christian Huitema <notifications@github.com> Mon, 07 January 2019 07:16 UTC

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Subject: Re: [quicwg/base-drafts] loss of only two packets can lead to an unrecoverable situation (#2267)
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I think this issue is an indirect justification for implicit ACK. The server may have dropped the handshake key, but it can send and receive 1-RTT packets. So can the client. If the client sends an 1-RTT packet after sending the CFIN, it should receive an ACK from the server. At that point, it knows there is no point in retransmitting the CFIN. If neither the 1-RTT not the CFIN handshake are acked, both can be repeated. If the handshake CFIN was received but the ACK lost, as @marten-seemann envisages, the server may not be able to process handshake packets anymore, but it can receive and ACK the 1-RTT packet.

Of course, that falls apart if the handshake and 1-RTT packets are coalesced. Maybe we need a warning there... 

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