Alternative ways to keeps ODCID on the server

[Dmitri Tikhonov <[e-mail]>]

Hello,

PR 3107 introduced the following text:

   If a server receives a client Initial that can be unprotected but
   contains an invalid Retry token, it knows the client will not accept
   another Retry token.  The server can discard such a packet and allow
   the client to time out to detect handshake failure, but that could
   impose a significant latency penalty on the client.  A server MAY
   proceed with the connection without verifying the token, though the
   server MUST NOT consider the client address validated.  If a server
   chooses not to proceed with the handshake, it SHOULD immediately
   close (Section 10.3) the connection with an INVALID_TOKEN error.
   Note that a server has not established any state for the connection
   at this point and so does not enter the closing period.

The problem with the "server MAY proceed" part is that the server's
transport parameters MUST include original_connection_id.  If ODCID
cannot be extracted from the invalid Retry token, then the server
cannot let this connection proceed.

Questions:

    1. The Retry token seems like the obvious place for the server
       to store ODCID.  Is there an implementation that does something
       else (state on server)?

    2. Should we spell out this caveat in the draft?  I.e. "server MAY
       proceed if it possesses ODCID."

Thanks,

  - Dmitri.