Re: Is round-trip time no longer a concern?
Dave Cridland <dave@cridland.net> Mon, 20 February 2006 16:20 UTC
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From: Dave Cridland <dave@cridland.net>
To: Eric Rescorla <ekr@networkresonance.com>
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Cc: Dave Crocker <dcrocker@bbiw.net>, IETF-Discussion <ietf@ietf.org>, iesg@ietf.org
Subject: Re: Is round-trip time no longer a concern?
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On Mon Feb 20 15:15:23 2006, Eric Rescorla wrote: > So, what I'm arguing is that except for applications where initial > connection setup is a large fraction of the cost of the entire > connection, I think it's not worth optimizing the initial connection > setup very much. And until you've profiled the protocols in > question it's hard to know which case you're in. > > I'll have to disagree almost totally. I think you always basically know what case you're in, because the connection setup time is wasted time that's not achieving anything useful, it's just staring-at-the-screen time. For a purely non-interactive protocol that a real human will never be waiting for results from, I suppose you could ignore any setup RTT cost, but I struggle to think of an example for this. For IMAP, where connection setup time is, in principle, a very small part of the total session time, it seems odd you're advocating that nobody should worry about adding round-trips when there's been substantial effort in reducing round-trips in precisely this area. Witness the way that the CAPABILITY command has been deprecated into a CAPABILITY response code, or the SASL-IR proposal, or RECONNECT - the list just goes on. Moreover, this phase of "reading your mail" is one where the user is definitely watching, and essentially nothing useful is happening. You absolutely know this is a good place to optimize. > >> Is it true that we no longer need to worry about regularly adding > >> extra round-trips to popular protocols that operate over the open > >> Internet? > > > > No. > > > > As far as I'm aware, there is no protocol in existence which > somebody, > > somewhere, does not actively use over a mobile phone link, or a > slow > > analogue modem, and this is especially true of TLS enabled > protocols > > such as HTTP, email protocols, etc. > > Well, I hear what you're saying, but when I check my mail over my > cell phone, it's pretty clear that the time isn't going to TLS > connection setup. Nope, but I'll bet that the time you spend waiting, rather than reading, is almost entirely round-trip latency, and not actual useful octets coming through the ether - silent noise and not shifting bits. Dave. -- You see things; and you say "Why?" But I dream things that never were; and I say "Why not?" - George Bernard Shaw _______________________________________________ Ietf mailing list Ietf@ietf.org https://www1.ietf.org/mailman/listinfo/ietf
- Re: Last Call: 'TLS User Mapping Extension' to Pr… Eric Rescorla
- Re: Last Call: 'TLS User Mapping Extension' to Pr… Steven M. Bellovin
- Re: Last Call: 'TLS User Mapping Extension' to Pr… Bill Fenner
- Re: Last Call: 'TLS User Mapping Extension' to Pr… Russ Housley
- Re: Last Call: 'TLS User Mapping Extension' to Pr… Russ Housley
- Is round-trip time no longer a concern? (was: Re:… Dave Crocker
- Re: Is round-trip time no longer a concern? Russ Allbery
- Re: Is round-trip time no longer a concern? (was:… Steven M. Bellovin
- Re: Last Call: 'TLS User Mapping Extension' to Pr… Bill Strahm
- Re: Is round-trip time no longer a concern? (was:… Dave Cridland
- Re: Is round-trip time no longer a concern? Harald Tveit Alvestrand
- Re: Is round-trip time no longer a concern? Peter Dambier
- RE: Last Call: 'TLS User Mapping Extension' to Pr… Pasi.Eronen
- Re: Is round-trip time no longer a concern? Eric Rescorla
- Re: Is round-trip time no longer a concern? Keith Moore
- Re: Is round-trip time no longer a concern? Dave Cridland
- Re: Is round-trip time no longer a concern? Dave Crocker
- Re: Is round-trip time no longer a concern? Eric Rescorla
- Re: Is round-trip time no longer a concern? Tony Finch
- Re: Is round-trip time no longer a concern? Steven M. Bellovin
- Re: Is round-trip time no longer a concern? Dave Crocker
- RE: Last Call: 'TLS User Mapping Extension' to Pr… Gray, Eric
- RE: [TLS] Re: Last Call: 'TLS User Mapping Extens… Pasi.Eronen
- Re: Last Call: 'TLS User Mapping Extension' to Pr… Bernard Aboba
- RE: Last Call: 'TLS User Mapping Extension' to Pr… Russ Housley
- RE: [TLS] Re: Last Call: 'TLS User Mapping Extens… Russ Housley
- RE: [TLS] Re: Last Call: 'TLS User Mapping Extens… Stefan Santesson
- RE: Last Call: 'TLS User Mapping Extension' to Pr… Stefan Santesson
- RE: Last Call: 'TLS User Mapping Extension' to Pr… Stefan Santesson
- RE: Re: [TLS] Re: Last Call: 'TLS User Mapping Ex… Stefan Santesson
- RE: Re: [TLS] Re: Last Call: 'TLS User Mapping Ex… Stefan Santesson
- RE: Re: [TLS] Re: Last Call: 'TLS User Mapping Ex… Russ Housley
- Re: Last Call: 'TLS User Mapping Extension' to Pr… Simon Josefsson
- Re: Last Call: 'TLS User Mapping Extension' to Pr… Jeffrey Hutzelman
- RE: [TLS] Re: Last Call: 'TLS User Mapping Extens… Ari Medvinsky