In the past one week I worked on Mindspeed slides, MICRO proposal.

I also spend a lot of time hacking the source code of Nepsim, an open
source simulation for Intel IXP1200 network processors. My purpose
is to figure out how it handles dynamic packet stream. By looking at
the programs I realize it uses a different approach to represent
packets. Currently we follow the method used in NetBench, where packets
are compiled into benchmarks. Benchmarks take parameters of how many
packets to process and the simulator just executed the benchmarks without
really worrying about packets. This method is fine for fix incoming
packet rate how not able to handle dynamically variable incoming packet
rate. The method in Nepsim instead makes use of the Intel IXP SDK
and generate a data file containing all packets, and decouple the
benchmarks from packets. It also models the input/output packet 
buffers and model the behavior of reading packets into those
buffers. The approach can be tranfered to our simulator as well.
What I need to do is to integrate some functionalities in 
Nepsim to our simulator, and generate packet stream by IXP SDK
by myself (or use their packets directly).