bandwidth and traffic simulator for web apps?

Question

Can you suggest how to create a test environment to simulate various types of bandwidths and traffic in a web app?

Or maybe an open source program which does this against

Answer 1

There are two approaches to shape network traffic to simulate a network link:

1. Run some software on the client or server that sits somewhere in the networking stack and shapes the traffic between the app and the network interface
2. Run the traffic shaping software on a dedicated machine with 2 network interfaces through which your traffic is routed

(2) is a better solution if you don't want to install software on the client or server (and possibly impact performance), but requires more hardware fiddling.

Some other features you might want to think about are what shaping parameters can be simulated. Most do delay and packet loss, some do jitter and bandwidth limiting as well. Some solutions can selectively filter traffic (for instance by port number, TCP or UDP etc).

Here is a list of some of the systems I've found:

Open Source or Freeware

DummyNet is an open source BSD Unix-based for dedicated devices. It is not clear if the software is being actively maintained

NistNet is an open source Linux-based system for dedicated devices. The software has not been actively maintained for several years.

Commercial

Apposite Technoligies sell dedicated hardware solutions for simulating WAN links, with a Web based GUI for configuring the settings and collecting traffic measurements

East Coast DataCom sell hardware dedicated simulators for simulating routers and modems

Itrinegy offer both dedicated device solutions, and solutions for running on clients or servers.

Network FX offer several dedicated device products for simulating network impairments between the client & server

NetLimiter is a client side system that allows throttling of individual applications, and includes a firewall.

Shunra Software offer a range of products, from high end enterprise WAN simulation and testing, to a simple client-resident emulator.