I work with packets and protocols. Most of my work has revolved around improving TCP/IP and making the network aware of transport metrics, improving both congestion control mechanisms and traffic engineering.
I also reverse engineer protocol behaviour in the wild, in particular through passive measurement techniques. Currently I'm responsible for processing and analysing one of the largest longitudinal datasets on Internet transit traffic.
My current toolchain involves piping pcap to python to SQL to R to gnuplot. In a past life I did kernel hacking in FreeBSD and validated crazy ideas in Network Simulator 2/3.