Re: [tcpm] Faster application handshakes with SYN/ACK payloads
Joe Touch <touch@ISI.EDU> Tue, 05 August 2008 23:47 UTC
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Date: Tue, 05 Aug 2008 16:46:44 -0700
From: Joe Touch <touch@ISI.EDU>
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To: Adam Langley <agl@imperialviolet.org>
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Subject: Re: [tcpm] Faster application handshakes with SYN/ACK payloads
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, Adam, Adam Langley wrote: | On Mon, Aug 4, 2008 at 11:20 AM, Joe Touch <touch@isi.edu> wrote: |> | Imaging that we change the sockets interface such that applications |> | get a callback when a SYN frame is received on a listening socket. |> | Applications could inspect the SYN frame and choose to enqueue data to |> | be written. Hopefully the kernel would send some of that data in the |> | SYNACK, but that's unimportant here. |> |> Why wouldn't the application just enqueue the data? Why does it need to |> know that the other end supports this? | | It doesn't always. SMTP, IRC and SSH protocols, for example, all | include a banner from the server to the client. In this case, the data | can be unconditionally enqueued for transmission. It's for protocols | which don't already start with a server->client transmission, and for | which we wish to add one, that the client must signal that we're | changing the application level protocol for this connection. Using a transport signal to change the application protocol seems very strange to me. Others can comment on that. My view is that this is a case where perhaps you want something that is better encoded by using a different port number (thus a different application service, explicitly) than a TCP option that implies that application behavior. |> 150ms is large when considered in the context of a small number of RTTs, |> but in the context of a connection that lasts 10 RTTs, it's 10%; the |> impact drops as you keep the connection going. |> |> I.e., a reduction of a single RTT is important only when the total |> exchange lasts 2-3 RTTs. That's 8KB-16KB of data - and it matters only |> for the first chunk of data in a persistent connection. For web pages |> with dozens of embedded components (in specific, more than 4, which is |> the typical limit for simultaneous connections), again this seems very |> much in the noise... | | Many Google users are now using search bars to submit queries. Thus | they type into a text field in the browser, hit enter and the browser | makes a connection, sends the query encoded in a GET and displays the | result. This is one example of a situation where the connection | latency isn't amortised. There are many others, but obviously, this is | the example that usually dominates my thinking. And, in this | situation, it turns out that every 10ms makes a difference. Understood and appreciated. Can you see if the port solution might work?? Joe -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkiY5mQACgkQE5f5cImnZrunEQCeJsum/G9ClwtD8cfX3zwrVZ8n EmAAoMlGT6BdWE3JfwTjTEcXVVjlJ9Qr =ctQh -----END PGP SIGNATURE----- _______________________________________________ tcpm mailing list tcpm@ietf.org https://www.ietf.org/mailman/listinfo/tcpm
- [tcpm] Faster application handshakes with SYN/ACK… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Lloyd Wood
- Re: [tcpm] Faster application handshakes with SYN… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Joe Touch
- Re: [tcpm] Faster application handshakes with SYN… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Michael Scharf
- Re: [tcpm] Faster application handshakes with SYN… Adam Langley
- [tcpm] Faster application handshakes with SYN/ACK… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Murali Bashyam
- Re: [tcpm] Faster application handshakes with SYN… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Joe Touch
- Re: [tcpm] Faster application handshakes with SYN… Joe Touch
- Re: [tcpm] Faster application handshakes with SYN… Joe Touch
- Re: [tcpm] Faster application handshakes with SYN… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Matt Mathis
- Re: [tcpm] Faster application handshakes with SYN… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Joe Touch
- Re: [tcpm] Faster application handshakes with SYN… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Joe Touch
- Re: [tcpm] Faster application handshakes with SYN… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Joe Touch
- Re: [tcpm] Faster application handshakes with SYN… Anantha Ramaiah (ananth)
- Re: [tcpm] Faster application handshakes with SYN… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Joe Touch
- Re: [tcpm] Faster application handshakes with SYN… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Joe Touch
- Re: [tcpm] Faster application handshakes with SYN… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Joe Touch
- Re: [tcpm] Faster application handshakes with SYN… Stefanos Harhalakis
- Re: [tcpm] Faster application handshakes with SYN… Joe Touch
- Re: [tcpm] Faster application handshakes with SYN… Stefanos Harhalakis
- Re: [tcpm] Faster application handshakes with SYN… Adam Langley
- Re: [tcpm] Faster application handshakes with SYN… Joe Touch
- Re: [tcpm] Faster application handshakes with SYN… Stefanos Harhalakis
- Re: [tcpm] Faster application handshakes with SYN… Stefanos Harhalakis
- Re: [tcpm] Faster application handshakes with SYN… Joe Touch