Re: [quicwg/base-drafts] Prohibit IP fragmentation (#3280)

Gorry Fairhurst <> Tue, 03 December 2019 07:39 UTC

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Date: Mon, 02 Dec 2019 23:39:40 -0800
From: Gorry Fairhurst <>
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Subject: Re: [quicwg/base-drafts] Prohibit IP fragmentation (#3280)
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gorryfair commented on this pull request.

> @@ -3471,6 +3471,10 @@ Datagrams containing Initial packets MAY exceed 1200 bytes if the client
 believes that the Path Maximum Transmission Unit (PMTU) supports the size that
 it chooses.
+UDP datagrams MUST NOT be fragmented at the IP layer.  In IPv4
+{{!IPv4=RFC0791}}, the DF bit MUST be set to prevent fragmentation on the path.
+Endpoints SHOULD discard fragmented IP packets.

I believe this is desirable at the receiving endpoint, but saying  "Endpoints SHOULD discard fragmented IP packets." ... isn't something that the transport has control over. I suggest you remove this. It seems sufficient to say at the sender don't do IPv4 or IPv6 fragmentation and do set FD

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