Re: [Sidrops] version negotiation

[Randy Bush <[e-mail]>]

claudio:

> I think paragraph 2 and 3 (both about Q < N) should be merged.

choice of style

> Current paragraph 4 makes the negotiation much clearer (but 'with a
> Protocol Version Q of the version N in the Error Report' is a mouth
> full).

some of us have big mouths :)

but i will confess to qualms about long run-on sentences.  i'll work on
that

> What is unclear what should happen when "unless it has already failed
> at that version" comes into play? Should it abort like in the last
> paragraph?

i think that is deadly.  speaking of run-on sentences

   If the router query has version Q > N, the cache MUST send an Error
   Report (Section 5.11) with Protocol Version N and Error Code 4
   ("Unsupported Protocol Version").  The router SHOULD send another
   query with a Protocol Version Q of the version N in the Error Report,
   unless it has already failed at that version, which indicates a fatal
   error in programming of the cache which SHOULD result in transport
   termination.

> Now this changes the sematics of Error Code 4.  So Section 13 needs to be
> adjusted. Error code 4 should not be fatal but have special handling as
> described in Section 7. This is required because:
>    Errors which are considered fatal MUST cause the session to be dropped,
>    and the router MUST flush all data learned from that cache.

i am less sure of this.  note that is the session which must be dropped,
not the transport.  and the session has not yet even been established
if we're still negotiating versions.

randy