Simulate Internet Connection & Bandwidth Speeds with Network Link Conditioner

Aug 10, 2011 - 9 Comments

Network Link Conditioner

A new addition to Mac OS X Lion and Xcode 4.1 is a utility called Network Link Conditioner, a highly customizable tool that lets you simulate a variety of common internet connectivity speeds. The utility is aimed at Mac and iOS developers so they can test their apps response times on a variety of network conditions, but it’s also extremely useful for IT admins, network administrators, and web developers.

  • Download and install Xcode 4.1 (App Store link) – free download for OS X 10.7 users
  • After Xcode is installed, head on over to:
  • /Applications/Utilities/Network Link Conditioner/

  • Double-click on “Network Link Conditioner.prefPane” to load the utility into System Preferences

You can start using the bandwidth simulator right away. Network Link Conditioner is fairly self explanatory, just select a bandwidth profile that you want to simulate and click the “ON” button to activate it immediately. The default choices are:

  • 3G – Average Case, Good Connectivity, or Lossy Network
  • Cable Modem
  • DSL
  • Edge – Average Case, Good Connectivity, or Lossy Network
  • Wifi – Average Case, Good Connectivity, or Lossy Network

If you find the existing bandwidth profiles too limiting, click on the little lock icon in the lower left corner, and then onto the “Manage Profiles” button in the bottom right to create or edit a new profile. Here you can set things like downlink and uplink bandwidth, up and down packets dropped, response delay, and even DNS delay.

Create a bandwidth and internet connectivity simulation profile

If you do any sort of development work, network administration, or anything else that requires testing potential users internet connectivity speeds, be it an iPhone app, usage of remote networks, or a web site, Network Link Conditioner is highly recommended, install it now.

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Posted by: William Pearson in Development, Mac OS X, Tips & Tricks


» Comments RSS Feed

  1. noah says:

    This could indeed be very useful for web developers. Similar things could be achieved on earlier versions of Mac OS X with ipfw(8)’s pipe and queue rules for dummynet(4).

  2. […] a great tool to have and a welcomed addition as part of the improvements made to Xcode for Lion. (via OS X Daily) 0.000000 […]

  3. Davis says:

    What a great find!

  4. […] OSXDaily Tags: 4.1实用小工具:模拟网络连接和带宽, Xcode Comments RSS […]

  5. […] i być może ten panel preferencji dostępny był już dawno, zwraca jednak na to uwagę serwis OS X Daily, który odkrył, że najnowsza wersja Xcode umożliwia doinstalowanie panelu preferencji […]

  6. Sad that is only for Lion.
    For OSX 10.5+ users there are other alternatives like Charles Proxy (paid) or Slowy (free,

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