Comments on: XMLHttpRequest (XHR) Uses Multiple Packets for HTTP POST? http://josephscott.org/archives/2009/08/xmlhttprequest-xhr-uses-multiple-packets-for-http-post/ Tue, 09 Mar 2010 16:29:18 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Joseph Scott http://josephscott.org/archives/2009/08/xmlhttprequest-xhr-uses-multiple-packets-for-http-post/#comment-19918 Joseph Scott Tue, 19 Jan 2010 14:11:22 +0000 http://josephscott.org/?p=1411#comment-19918 Nice, glad it helped. Nice, glad it helped.

]]> By: Maurits http://josephscott.org/archives/2009/08/xmlhttprequest-xhr-uses-multiple-packets-for-http-post/#comment-19911 Maurits Tue, 19 Jan 2010 12:57:46 +0000 http://josephscott.org/?p=1411#comment-19911 Thank you very much! We have such a web app that is doing lots of updates and to us this is enormously important. After doing some wiresharking and emulating some loss, jitter, low bandwidth and reordering (using tc) and reading your post I decided to change all the ajax post requests to ajax get requests hoping it had something to do with the 2 packet issue. And it did: after that no more strange 404's on the ajax calls appeared in the apache access log. I still didn't figure out why exactly, but emulating these conditions is no easy task either, so I may never find out. Thank you very much! We have such a web app that is doing lots of updates and to us this is enormously important. After doing some wiresharking and emulating some loss, jitter, low bandwidth and reordering (using tc) and reading your post I decided to change all the ajax post requests to ajax get requests hoping it had something to do with the 2 packet issue. And it did: after that no more strange 404’s on the ajax calls appeared in the apache access log. I still didn’t figure out why exactly, but emulating these conditions is no easy task either, so I may never find out.

]]> By: Joseph Scott http://josephscott.org/archives/2009/08/xmlhttprequest-xhr-uses-multiple-packets-for-http-post/#comment-14621 Joseph Scott Mon, 16 Nov 2009 16:36:48 +0000 http://josephscott.org/?p=1411#comment-14621 It's over TCP so any lost packets would be resent by the networking layer, below the browser. It’s over TCP so any lost packets would be resent by the networking layer, below the browser.

]]> By: chandru http://josephscott.org/archives/2009/08/xmlhttprequest-xhr-uses-multiple-packets-for-http-post/#comment-14439 chandru Fri, 13 Nov 2009 15:44:15 +0000 http://josephscott.org/?p=1411#comment-14439 Hi, First of all thank you very much for such a good article. Do you have any idea on what happens if second packet gets lost in the post operation? I am running out of one problem just trying to correlate my problem with this article. Thanks & regards, chandru Hi, First of all thank you very much for such a good article. Do you have any idea on what happens if second packet gets lost in the post operation? I am running out of one problem just trying to correlate my problem with this article.

Thanks & regards,
chandru

]]> By: JimmyLi.net » Guide to Bandwidth in packets http://josephscott.org/archives/2009/08/xmlhttprequest-xhr-uses-multiple-packets-for-http-post/#comment-12452 JimmyLi.net » Guide to Bandwidth in packets Mon, 19 Oct 2009 02:56:15 +0000 http://josephscott.org/?p=1411#comment-12452 [...] blog article also has an interesting link to another interesting article measuring that XMLHttpRequest uses 2 packets to send POST data (for most browsers).  You should [...] [...] blog article also has an interesting link to another interesting article measuring that XMLHttpRequest uses 2 packets to send POST data (for most browsers).  You should [...]

]]> By: Joseph Scott http://josephscott.org/archives/2009/08/xmlhttprequest-xhr-uses-multiple-packets-for-http-post/#comment-11917 Joseph Scott Mon, 05 Oct 2009 16:00:00 +0000 http://josephscott.org/?p=1411#comment-11917 Determining if this is hugely important depends on what you are using the XHRs for. For basic things like submitting a form without reloading the page, sure, not a big deal. If you have a web app that is doing lots of updates (chat, live stream, etc.) then it could become enormously important. Determining if this is hugely important depends on what you are using the XHRs for. For basic things like submitting a form without reloading the page, sure, not a big deal. If you have a web app that is doing lots of updates (chat, live stream, etc.) then it could become enormously important.

]]> By: Matt Chatterley http://josephscott.org/archives/2009/08/xmlhttprequest-xhr-uses-multiple-packets-for-http-post/#comment-11867 Matt Chatterley Sun, 04 Oct 2009 08:57:18 +0000 http://josephscott.org/?p=1411#comment-11867 Thanks for taking the time out to test this - it's an interesting fact, albeit perhaps not a hugely important one. If you're using XHR to replace conventional postbacks, the odds are that you will be sending a lot less post-data, because you'll be doing fragmented transactions (however you want to call them) - so it's probably a net gain overall in most situations! Thanks for taking the time out to test this – it’s an interesting fact, albeit perhaps not a hugely important one.

If you’re using XHR to replace conventional postbacks, the odds are that you will be sending a lot less post-data, because you’ll be doing fragmented transactions (however you want to call them) – so it’s probably a net gain overall in most situations!

]]> By: Joseph Scott http://josephscott.org/archives/2009/08/xmlhttprequest-xhr-uses-multiple-packets-for-http-post/#comment-11785 Joseph Scott Fri, 02 Oct 2009 16:33:49 +0000 http://josephscott.org/?p=1411#comment-11785 Both network.http.pipelining and network.http.proxy.pipelining (though I did not use a proxy) are set to false. For the most part the Firefox installs are fairly stock, with just a couple of plugins installed. Both network.http.pipelining and network.http.proxy.pipelining (though I did not use a proxy) are set to false. For the most part the Firefox installs are fairly stock, with just a couple of plugins installed.

]]> By: AlwaysLearning http://josephscott.org/archives/2009/08/xmlhttprequest-xhr-uses-multiple-packets-for-http-post/#comment-11745 AlwaysLearning Thu, 01 Oct 2009 23:48:53 +0000 http://josephscott.org/?p=1411#comment-11745 Another possibility... does your Firefox config have network.http.pipelining and/or network.http.proxy.pipelining options set to true? If so, try setting them to false and repeating your tests. Another possibility… does your Firefox config have network.http.pipelining and/or network.http.proxy.pipelining options set to true? If so, try setting them to false and repeating your tests.

]]> By: Joseph Scott http://josephscott.org/archives/2009/08/xmlhttprequest-xhr-uses-multiple-packets-for-http-post/#comment-11744 Joseph Scott Thu, 01 Oct 2009 23:33:26 +0000 http://josephscott.org/?p=1411#comment-11744 No proxy, just Wireshark to watch the network traffic. No proxy, just Wireshark to watch the network traffic.

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