Re: [quicwg/base-drafts] Request to Retire Locally Issued CIDs (#2769)

[ianswett <[e-mail]>]

ianswett commented on this pull request.

I'd like to make it a protocol violation for the gap between the CID sequence number and the "Retire Prior To" value being more than the active_connection_id_limit specified in the transport params.  Previously people said implementing that was too difficult, but having both values in a single frame make it pretty easy to get right and detect when it's violated.

@marten-seemann 

> @@ -994,6 +994,14 @@ packets sent from only one local address.  An endpoint that migrates away from a
 local address SHOULD retire all connection IDs used on that address once it no
 longer plans to use that address.
 
+The endpoint can explicitly request its peer to retire connection IDs by sending
+a NEW_CONNECTION_ID frame that contains a Retire Prior To field.  The peer is
+required to retire these connection IDs in a timely manner.  On receipt of the
+acknowledgement for the packet that contained the NEW_CONNECTION_ID frame, the
+endpoint may start a 3 PTO timer, which on expiring may close the connection
+with a PROTOCOL_VIOLATION error if all the connection IDs were not retired as
+requested.
+

I was going to suggest that the peer MUST change CIDs immediately or the issuer MAY close the connection.  Admittedly that could cause the sender of CIDs to burn through a CID per packet, but I'm not sure what its incentive to do that would be?

> @@ -5018,10 +5034,16 @@ sequence number, or if a sequence number is used for different connection
 IDs, the endpoint MAY treat that receipt as a connection error of type
 PROTOCOL_VIOLATION.
 
+If the Retire Prior To field is present it is a request for the peer to
+immediately retire all connection IDs with a sequence number less than the
+specified value.  For more information see {{retiring-cids}}.  This field
+should only ever increase, though reordering and retransmission of older packets

I think you can say that the field MUST not decrease if the CID sequence number increases?

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/quicwg/base-drafts/pull/2769#pullrequestreview-245723996