Subject: [Errata Verified] RFC9000 (6811)

From: RFC Errata System <[email-masked]>
Date: Fri, 18 Feb 2022 02:18:41 -0800 (PST)

The following errata report has been verified for RFC9000,
"QUIC: A UDP-Based Multiplexed and Secure Transport". 

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You may review the report below and at:
https://www.rfc-editor.org/errata/eid6811

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Status: Verified
Type: Technical

Reported by: Martin Thomson <[email-masked]>
Date Reported: 2022-01-06
Verified by: Zaheduzzaman Sarker (IESG)

Section: 5.1.1

Original Text
-------------
                                         The sequence number of the
   initial connection ID is 0.  If the preferred_address transport
   parameter is sent, the sequence number of the supplied connection ID
   is 1.

   Additional connection IDs are communicated to the peer using
   NEW_CONNECTION_ID frames (Section 19.15).  The sequence number on
   each newly issued connection ID MUST increase by 1.  

Corrected Text
--------------
                                         The sequence number of the
   initial connection ID is 0.  If the preferred_address transport
   parameter is sent, the sequence number of the supplied connection ID
   is 1.  The sequence number for NEW_CONNECTION_ID frames starts at 2
   when the preferred_address transport parameter is sent and 1
   otherwise.

   Additional connection IDs are communicated to the peer using
   NEW_CONNECTION_ID frames (Section 19.15).  The sequence number on
   each newly issued connection ID MUST increase by 1.

Notes
-----
It is not sufficiently clear that the (implied) sequence number for the preferred_address transport parameter is taken from the sequence only when the transport parameter is present.

The original text might be read to imply that the first NEW_CONNECTION_ID frame always starts with 2, though maybe only at a server.  The proposed addition is much more explicit.

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RFC9000 (draft-ietf-quic-transport-34)
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Title               : QUIC: A UDP-Based Multiplexed and Secure Transport
Publication Date    : May 2021
Author(s)           : J. Iyengar, Ed., M. Thomson, Ed.
Category            : PROPOSED STANDARD
Source              : QUIC
Area                : Transport
Stream              : IETF
Verifying Party     : IESG