RE: [Sip] Editorial question on MIME example

> Now, as far as I know (please correct me if I am wrong) Content-Length
> is NOT a MIME header.

Right, it isn't.  It could be argued that SIP's Content-Length was taken from
HTTP (RFC1945) rather than MIME.  It could be argued HTTP took the idea from
email -- Content-Length used to be common in email headers a decade or two ago
(but Content-Length didn't work too well for email for a variety of reasons).
RFC2076 (February 1997) lists it, and says it was not a standard email header
at the time.

> If so, I guess it shouldn't be used as a MIME
> header (together with Content-Type, Content-Transfer-Encoding etc)?

RFC2045 does say:

   Any sort of field may be present in the header of an entity,
   but only those fields whose names begin with "content-" actually have
   any MIME-related meaning.

but of course Content-Length doesn't have any meaning to MIME (neither would
Content-Crayon).  But neither of those headers do harm to a MIME parser,
because a MIME parser ignores fields it doesn't understand.

I guess you're saying SIP should have used something like "Length:" instead of
"Content-Length:" to avoid collision with MIME's self-claimed ownership of all
field names that begin with "Content-"?

-d

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