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I notice that iTunes seems to suck up all my bandwidth and doesn’t play nice with other applications that use the web when it's downloading. In fact, it doesn't even give itself enough bandwidth when browsing the iTunes Store while downloading large or many files (podcasts, TV shows, large apps, etc).

I'm not concerned with getting all my downloads as soon as possible, they're really low priority, and I'd rather not have to do this while I'm awake, but I can't hit the refresh button if I'm in bed and forgot it already.

Is there an application or tool via the Terminal to limit the download bandwidth that iTunes gets without also hindering web browsers or other applications?

FOSS/GPL software is preferable, but pay software might be acceptable too.

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7 Answers 7

How about waterroof? It's an easy front end for IPFW. (And open source.)

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1  
Very nice, I'll have to look at it later. Are you aware of any tutorials on it for my intended use? –  Kio Dane Apr 9 '10 at 15:32

Use IceFloor on [Mountain] Lion

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This is a really perverse thought, but you might be able to use Mac OS X's built-in ipfw and dummynet to write rules to do this. See the man pages for those tools.

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A video of someone doing just that on OSX: youtube.com/watch?v=VgwR230coOw –  Prof. Falken Jun 8 '11 at 9:42

GUI:

CLI (no port-specific filtering but can be adapted):

These tools rely on ports or port ranges as a filter criterium. If you don't know what ports your application uses you can check its documentation or use lsof while the appplication is running to reveal the ports numbers.

sudo lsof -i -P

Most or all of the tools use ipfw which is officially deprecated in favor of pf, so not sure if these solutions will work on OS X 10.9 and beyond.

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Old question, but I just got in the thick of a similar problem so I thought I'd reply.

The problem is probably actually due to traffic shaping at your ISP. They aggressively prioritize traffic to known content providers in an effort to provide better streaming service to customers. I'd argue they've gone a little too far in some cases - I just diagnosed a similar problem where a background iCloud photo upload was causing ping times in excess of 45000 ms.

In order to resolve the problem, you can simply reduce the amount of total bandwidth your computer will use in order to prevent the ISP's traffic shaping from completely robbing bandwidth from all other applications. Ironically, this will improve browsing performance on your own computer, in addition to obviously improving performance for other computers on your network. If for example you've got a 15Mbps downstream cap, you can limit your computer to only using 12Mbps of it, and the ISP algorithm will no longer see the need to shape your traffic as aggressively:

sudo ipfw pipe 1 config bw 12Mbits/s
sudo ipfw add 1 pipe 1 tcp from any to me

In my case, it was upstream bandwidth (capped at 1Mbps by my ISP) that was the limiting factor, so I ran the following, which solved my problem:

sudo ipfw pipe 1 config bw 768Kbits/s
sudo ipfw add 1 pipe 1 tcp from me to any

Note that these commands will only be effective until a restart, but to cancel the rule, just do the following:

ipfw delete 1
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I find the FreeBSD man page for ipfw, but according to Wikipedia, ipfw was de-emphasized in OS X starting in 10.4 thru 10.5. I don't find ipfw on my installation of 10.10 today, and both Homebrew and MacPorts come up with no actively developed installations for ipfw. –  Kio Dane Sep 24 at 14:08

trickle is what you're after.

The only issues are that it does not support executables utilizing kqueue, and it does not support statically linked executables. iTunes should be fine.

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I couldn't get trickle 1.0.6 or 1.0.7 to build. After running ./configure I get an error saying that libevent cannot be found. I installed libevent via MacPorts and got the same error when I tried again. –  Kio Dane Apr 2 '10 at 14:00
    
@Kio versions > 1.06 do not build due to problems with the call to poll(). Older ones should work however. –  John T Apr 2 '10 at 22:00
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I downloaded trickle 1.0.5, ran "$ sudo ./configure" and got the following error just like before: "configure: error: libevent not found". I checked, and MacPorts has libevent installed. Besides, I'm not as fond of software that hasn't been updated in years. –  Kio Dane Apr 4 '10 at 0:35

http://github.com/zquestz/throttled this might be what you're after if you've not found it yet.

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Looks really good. –  Prof. Falken Jun 8 '11 at 9:44

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