On 11 November 2015 at 21:00, Tony Finch <[email protected]> wrote: > Dave Cridland <[email protected]> wrote: > > > > This is desirable, because the essential service offered by an MTA is > equal > > irrespective of the domain of the email, and it's possible (and sensible) > > to use multiple, concurrently pipelined transactions for multiple > recipient > > domains. (And yes, this requires an interesting combination of ESMTP > > service extensions, but it is possible). > > Even basic SMTP allows multiple different recipient domains on a single > transaction, no pipelining needed. Standard ESMTP only allows pipelining > within transactions. > > Well. If you're going to be picky... :-)
Standard ESMTP doesn't allow pipelining at all, you'd need RFC 2920 support for that - however that won't pipeline an entire transaction, since it forces a wait after the DATA for the 3xx response. However, I don't think it mandates a wait after the message transmission itself, so you can pipeline the message transmission from one transaction into the envelope commands of the next. To pipeline within (and through) transactions you need, of course, the CHUNKING extension from RFC 3030. > I would advise against trying to pipeline multiple transactions because > of bad interactions with abrupt TCP connection loss. The experimental > extension RFC 1845 attempts to improve this, but it has problems. See > <https://tools.ietf.org/html/draft-fanf-smtp-rfc1845bis>. > > That's a fair comment, though losing the TCP abruptly at any time after the client thinks it has transmitted the message and before the response comes back is bad; pipelining simply exacerbates the problem. In XMPP, we addressed this issue with XEP-0198, of course. > I now return you to more directly topical subjects. Sorry about the > digression :-) > > These digressions are often more interesting than the main discussion. Besides I mentioned XMPP back there and a XEP, so we're back on topic, right? > South Biscay, Southeast Fitzroy: Variable 3 or 4, becoming southwesterly 4 > or > 5 later. Rough. Occasional drizzle. Good, occasionally moderate. > Quite surprised it's not worse. Dave.
