How do I simulate a low bandwidth, high latency environment?

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I need to simulate a low bandwidth, high latency connection to a server in order to emulate the conditions of a VPN at a remote site. The bandwidth and latency should be tweakable so I can discover the best combination in order to run our software package.

For macOS, there is the Network Link Conditioner that simulates configurable bandwidth, latency, and packet loss. It is contained in the Additional Tools for Xcode package.

Why Is My Internet So Slow?, How do you simulate a slow Internet connection on a Mac? Fiddler supports Global proxying via GeoEdge, and its custom rules can be used to simulate modem speeds: Test on an impaired network. Software and hardware proxies enable you to emulate problematic mobile network conditions, such as bandwidth throttling, packet delay, and random packet loss.

There's an excellent writeup of setting up a FreeBSD machine to do just this - take your standard old desktop, toss in an additional NIC, and build.

The writeup is available at http://www.freebsd.org/doc/en/articles/filtering-bridges/article.html.

In step 5 of the above instructions, you're enabling a firewall. For just simulating a different IP connection, you could (for example) do the following:

Create a file /etc/rc.firewall.56k which contains the following:

ipfw add pipe 1 ip from any to any out
ipfw add pipe 2 ip from any to any in    
ipfw pipe 1 config bw 56Kbit/s   
ipfw pipe 2 config bw 56Kbit/s

And change /etc/rc.conf... replace the line

firewall_type="open"

with

firewall_type="/etc/rc.firewall.56k"

reboot, and you've got yourself a 56K bridge!

If you happen to be working from a Macintosh, that OS has ipfw built into it by default. I've done the same thing by routing network traffic over the Airport and through the ethernet, setting it up so that anything coming over the airport has the same characteristics as whatever I'm trying to emulate. You can invoke the ipfw commands directly from the terminal and get the same effects.

What is it latency and how does it kill fast internet?, A range of software tools can help you emulate and simulate low bandwidth and high latency. Emulate network throttling. When building or  Many people don't know how to simulate simulate low bandwidth or think it's hard to set up. Simulating low bandwidth with Google Chrome. If you're using Google Chrome, you can go to the Network Tab in F12 Tools and select a bandwidth level to simulate: Even better, you can also add Custom Profile to specify not only throughput but custom latency:

In the past, I have used a bridge using the Linux Netem (Network Emulation) functionality. It is highly configurable -- allowing the introduction of delays (the first example is for a WAN), packet loss, corruption, etc.

EDIT: There is also the MasterShaper web interface to control the settings.

I'm noting that Netem worked very well for my applications, but I also ended up using WANem several times. The provided bootable ISO (and virtual appliance images) made it quite handy.

How to Simulate Network Outages, How can I simulate a bad internet connection with high latency, low bandwidth, jitter and occasional packet loss when in a local environment? Charles can be used to adjust the bandwidth and latency of your Internet connection. This enables you to simulate modem conditions using your high-speed connection. The bandwidth may be throttled to any arbitrary bytes per second. This enables any connection speed to be simulated. The latency may also be set to any arbitrary number of milliseconds.

Charles

I came across Charles the web debugging proxy application and had great success in emulating network latency. It works on Windows, Mac, and Linux.

Bandwidth throttle / Bandwidth simulator

Charles can be used to adjust the bandwidth and latency of your Internet connection. This enables you to simulate modem conditions using your high-speed connection.

The bandwidth may be throttled to any arbitrary bytes per second. This enables any connection speed to be simulated.

The latency may also be set to any arbitrary number of milliseconds. The latency delay simulates the latency experienced on slower connections, that is the delay between making a request and the request being received at the other end.

DummyNet

You could also use vmware to run BSD or Linux and try this article (DummyNet) or this one.

Bandwidth throttling / simulation in macOS (OS X), How to Simulate a Slow Internet Connection for Testing few people are browsing my site with an ultra-high-speed broadband connection. from Offline to WiFi and the numbers are shown as Latency, Download, Upload. simulate network latency windows (18) I need to simulate a low bandwidth, high latency connection to a server in order to emulate the conditions of a VPN at a remote site. The bandwidth and latency should be tweakable so I can discover the best combination in order to run our software package.

I found this little neat program for Windows called clumsy. It's in kind of alpha status, but it seem to work fine for me, and it's open source.

Edit: Others have noticed that you can't limit bandwidth with clumsy, and that's true. You can only add Latency and a couple of other network related errors. This will disqualify this answer as a valid answer to the question, however since I had good use for it when I wanted to simulate a bad network so I'll leave it here as long as it has > 0 votes or similar.

Understanding Low Bandwidth and High Latency, Most routers allow you to limit bandwidth, but that's only half the story. Lots of ideas here on simulating a low bandwidth, high latency connection: .com/​questions/130354/how-do-i-simulate-a-low-bandwidth-high-latency-environment. Wireshark is a network protocol analyser and cannot generate traffic nor simulate network issues. Maybe there are items on the Tools page on the Wiki that can help.

How can I simulate a bad internet connection for testing purposes , Aha! It works if we reverse the order of the commands. tc qdisc add dev lo root handle 1: htb default 12 tc class add dev lo parent 1:1 classid  Now that you know what a slow network connection consists of, let’s make one for ourselves. What we need are tools to simulate a low bandwidth, high latency connection perhaps even with some packet loss. First let’s start with creating a low bandwidth connection. A tool I often use for this is NetLimiter. We will need the Pro version.

How to Simulate a Slow Internet Connection for Testing, I'd like to simulate a high-latency, low-bandwidth network connection on my Linux machine. Limiting bandwidth has been discussed before, e.g. here, but I can't  slow 3G # Slow network on default eth0 down to 3G wireless speeds slow reset # Reset connection for default eth0 to normal slow vsat --latency=500ms # Simulate satellite internet with a high latency slow dsl -b 1mbps # Simulate DSL with a slower speed than the default slow modem-56k -d eth0 # Simulate a 56k modem on the eth1 device.

[SOLVED] Bandwidth limiting software, East Coast Datacom, Inc manufactures network latency simulators and wan your applications in a lab environment by emulating bandwidth, latency, loss and jitter of wide area networks. The PDS-1G or PDS-10G is a mini low cost Portable Delay Simulator UDC-RDS, HIGH SPEED NETWORK LATENCY EMULATOR. How can I simulate a bad internet connection with high latency, low bandwidth, jitter and occasional packet loss when in a local environment? If you're on Windows, you can try SoftPerfect Connection Emulator. It's basically a driver that injects itself between your application and the network layer (similar to Wireshark/WinPCAP) for the selected NIC and can simulate limited bandwidth, latency, packet loss, and other things.

Comments
  • Great question! I'd love to hear some answers related to ASP .NET web development.
  • Related/dupe: Network tools that simulate slow network connection & Simulate delayed and dropped packets on Linux
  • The "Network Link Conditioner" preference pane is part of the Hardware IO Tools for XCode, which you can download from developer.apple.com/downloads
  • doesn't seem to work with Genymotion. (Black Screen)
  • Download link for newer XCode versions: developer.apple.com/download/more/?q=Additional%20Tools
  • @jstorm31 Thank you. I've updated the answer with the current name of the package and current link.
  • Perfect for my needs, and available out of the box on my Ubuntu 14.04 server!
  • Charles is an HTTP proxy, and therefore only suitable for testing HTTP applications. To each their own, but in my opinion it's probably some of the worst software I've ever used. I only used it for a short time while I had to work on a Mac. For Windows users, I'd recommend Fiddler if you need an HTTP debugging proxy. Unfortunately, I didn't find anything other than Charles for OSX.
  • Hi Brad. Can you mention what kind of problems did you have?
  • How do you control bandwidth with clumsy?
  • Excellent program. Just what I needed. I Recommend it. Works like a charm and its super easy.