Comments on: Testing IE8′s Connection Parallelism

By: Bruce Stoner

Bruce Stoner — Mon, 07 Dec 2009 02:34:56 +0000

Internet Explorer 8 seems to be better than any previous version of IE. IE8 is very stable and rarely crashes or cause blue screens.

By: Lori MacVittie

Lori MacVittie — Wed, 03 Sep 2008 18:49:58 +0000

This is an astounding article, thank you! I've spoken and written a lot about AJAX and connection management issues in general and this really puts some hard numbers and empirical data around the subject. I haven't read your blog before, but I'm coming back for more now. Great stuff! Lori

By: Paddy

Paddy — Fri, 27 Jun 2008 18:31:05 +0000

All the tests of your connection parallelism apply to users who are far away from the origin server. For example, if your server is in San Jose, whats the effect of 4 parallel connections for San Jose users (guess? its gonna be worse than single connection)

Look at their bandwidth-delay product and knowing full well that TCP cannot send less than 1MSS, 4 connections will have to tranmit the slowest at 4*1KB *8b/B/RTT = 32 Kb/RTT and RTT here is very small like 10ms. This means queuing will inevitable happen.

try the opening page of http://www.hotmail.com from san jose to see what I mean..

That said, you results are very relevant for dissemination of content from a single server. For distributed servers, people close enough to the edges, this would be counter-productive.

By: Ryan Breen

Ryan Breen — Mon, 09 Jun 2008 12:15:31 +0000

Mark,

Being wrong made me think there was a limit to concurrent connections. It’s a longstanding misconception I had, but it has since been corrected. The only limit is per host.

I don’t see any issues with my test pages. I have intermittent problems with dreamhost, but everything appears to be functional now.

By: Mark

Mark — Mon, 09 Jun 2008 07:52:10 +0000

What makes you think WinINET has any limit to concurrent connections at all?

your test pages are broken, btw.

By: Biondi Tang

Biondi Tang — Wed, 21 May 2008 06:27:44 +0000

I used IE8 getting the same page at http://demo.ajaxperformance.com and saw a quite different graph in Page Detailer. The number of parallel connections started from 3 in the first round, 5 the second, 9 the third, and another 9 the fourth, for the total of 26 images.

While running in IE7 Emulate mode, a different graph with 6, 6, 4, 4, 6 parallel connections in 5 rounds.

I think there might be some other factors affecting the result such as file size, internet connection bandwidth, local cache…etc.

I was considering to use “web accelerator” appliance that do the same job by layer 7 protocol. It seems that this “multi-connect” acceleration will be replaced by next version of browsers. Any similar case to share?

By: Steve Laniel

Steve Laniel — Mon, 17 Mar 2008 12:51:20 +0000

I’m surprised the browser can’t learn what the optimum number of parallel connections is, and adjust over time. That seems like an obvious next step. I wonder if other browsers will learn from this performance analysis and do IE one better.

By: andrew

andrew — Mon, 17 Mar 2008 11:57:59 +0000

I use Opera browser. I can set up up to 128 (!) connection per server, and up to 128 connections total.

Just choose Tools-Preferences-Advanced-Network.

The defaults are 8 and 20 respectivly, and I don’t know why.

By: Pelican

Pelican — Mon, 17 Mar 2008 02:30:22 +0000

Lovely article. I keep following your connection stuff and cannot believe it is 18 now..I use Gomez a lot and those numbers definitely make sense..BTW do you have any official confirmation of this from the IE team?