Adam Roach <adam(_at_)nostrum(_dot_)com> writes:
To be clear (and this is an easy mistake to make, since the sections and
their contained steps are huge), Pete is referring to the long-form
version of step 6 in section 16.7 here. See RFC 3261, page 111.
Ah, there's a tension between this paragraph:
The stateful proxy MUST choose the "best" final response among
those received and stored in the response context.
and this one:
3-6xx responses are delivered hop-by-hop. When issuing a 3-6xx
response, the element is effectively acting as a UAS, issuing
its own response, usually based on the responses received from
downstream elements. An element SHOULD preserve the To tag
when simply forwarding a 3-6xx response to a request that did
not contain a To tag.
But if many implementations take "choose the best final response" to
mean only re-sending the response code, we have a problem.
OTOH, it's quite possible to reserve a *set* of 6xx response codes to
carry the decline-type. The only allocated 6xx responses are 600
(generic), 603, 604, and 606.
Dale