Testing protocol implementations prior to release can save a company time and money. It can also prevent bugs that could leave your customers vulnerable.

"Before a recent release we decided to use the Maxwell Pro TCP/IP Test Suite to test our TCP stack; the results were surprising. We thought we were ready, but Maxwell Pro found more bugs than we had anticipated."

-Dave Taht, CeroWrt

CeroWrt's Mission

  • To build a faster, more reliable and less annoying internet for home users.
  • To make video conferencing and gaming possible while downloading music and movies.

Most network devices today have been built with way too much buffering. This negatively impacts interactive traffic, like voice and video. Finding an algorithm for the “right” amount of buffering on the network is a thirty year old, mostly unsolved research problem.

Company Profile:

CeroWrt is a project built on the OpenWrt firmware to both resolve the endemic problems of bufferbloat in home networking today, and to push forward the state of the art of edge networks and routers. Projects include proper IPv6 support, tighter integration with DNSSEC, and most importantly, reducing bufferbloat in both the wired and wireless components of the stack.

CeroWrt is a home router project that's been developed by a group of engineers who have made it their mission to make the internet faster and more reliable. It's a research platform for engineers to convert bufferbloat fixes from theory into reality.


CeroWrt believes it has found the fixes for bufferbloat and needs to get its solution from the lab and into the real world as soon as possible. CeroWrt has complicated algorithms and wanted to make sure its users are able to focus on the research and not the bugs in the network stack. CeroWrt's engineers have worked on only a few thousand of the millions of lines of code that might have broken along the way.

Testing the TCP, IPv4, and IPv6 implementation

The Maxwell Pro TCP/IP Test Suite reported 45 bugs while testing CeroWrt, including a crash bug. Most of the bugs were differences in the interpretation of one RFC or another. Some of these bugs needed to be fixed, one had a CRC issue in one test. The most important find was the crash bug, which turned out to be a fragmentation or encapsulation bug.

“The Maxwell Pro test suite pushes the boundaries of every TCP, IPv4, and IPv6 implementation. Finding that crash bug alone was worth the price of admission. I was simply delighted by the Maxwell Pro toolset. In addition to the thorough protocol test suite, Maxwell Pro provides easy to use tools with sliders and so on to simulate delay and packet loss in a fast, natural, intuitive manner.”“I plan to test CeroWrt against Maxwell Pro's tools again once I have worked out the bugs!”

-Dave Taht, CeroWrt

CeroWrt may be reached at:

More Information on IWL and the Maxwell Pro Test TCP/IPSuite:
PO Box 66190
Scotts Valley, CA 95067

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