Draft: draft-ietf-quic-transport

Commentary: Note that may want to change the phrasing of the ODCID field , depending on which PR lands first . 
 End of section 18 , transport It seems the term is " initial connection ID " not " original connection ID " , at least I ca n't find it defined anywhere in transport . 
 Two different things , but you 're probably right that they should both be explicitly defined : The " Original destination connection ID " is the DCID used in the client 's very first Initial packet . If the server responded with a Retry , the server needs to : include the ODCID in the Retry packet to verify the Retry packet came from something on - path include the ODCID in the eventual handshake 's transport parameters to verify that the Retry packet originated from the server or something cooperating with it , not a MITM The " Initial connection ID " is the DCID used in the client 's Initial packet to which the server responded with an Initial . This CID determines the keys used for Initial packets throughout the handshake . ( But see . ) This CID might have been server - chosen ( from a Retry ) or client - chosen ( no Retry ) . If there 's no Retry packet , they refer to the same CID , but I do n't think there 's a reference to the ODCID outside the context of a Retry . 
 I think that we already concluded this in . 
 This is a separate issue , about definition of these terms ; is about whether these need to be separate concepts depending on the outcome of other issues . notes that the term " original connection ID " appears only to say that a client MUST NOT send one , and that literal string appears nowhere else in the document except the changelog . This refers to the transport parameter , whose definition matches the description of the " Original Destination Connection ID " field in Retry and references Retry , but does n't use that term . I 'd suggest using the names of the prohibited TPs in stating the client restriction , and referencing the " Original Destination Connection ID " field by name from the TP definition .
Paragraph (version A):
The value of the Destination Connection ID field from the first
Initial packet sent by the client.  This transport parameter is
only sent by a server.  A server MUST include the
original_connection_id transport parameter if it sent a Retry
packet.
Paragraph (version B):
The value of the Destination Connection ID field from the first
Initial packet sent by the client.  This transport parameter is
only sent by a server.  This is the same value sent in the
"Original Destination Connection ID" field of a Retry packet (see
packet-retry).  A server MUST include the original_connection_id
transport parameter if it sent a Retry packet.
Paragraph (version A):
A client MUST NOT include an original connection ID, a stateless
reset token, or a preferred address.  A server MUST treat receipt of
any of these transport parameters as a connection error of type
TRANSPORT_PARAMETER_ERROR.
Paragraph (version B):
A client MUST NOT include server-only transport parameters
(original_connection_id, stateless_reset_token, or
preferred_address).  A server MUST treat receipt of any of these
transport parameters as a connection error of type
TRANSPORT_PARAMETER_ERROR.