att/ryu — pull request #2 by powerist (2013-07-30 21:15:18+00:00)
Title: Unfinished inception_arp.py

The problem is "None" value of dpid on start-up
The reason is wrongly extracting dpid from "Hello" event.
"Hello" event does not provide dpid.

Potential event providing dpid is "EventDP".
Have not had the chance to try it out.