packetdrill article in October USENIX ;login:

[Neal Cardwell]

This may be of interest to the list:

http://research.google.com/pubs/pub41848.html

"""
Drilling Network Stacks with packetdrill

Abstract: Testing and troubleshooting network protocols and stacks can
be painstaking. To ease this process, our team built packetdrill, a
tool that lets you write precise scripts to test entire network
stacks, from the system call layer down to the NIC hardware.
packetdrill scripts use a familiar syntax and run in seconds, making
them easy to use during development, debugging, and regression
testing, and for learning and investigation.
"""

It includes some how-to tips and some details about the ECN support,
among other things.

neal