Hi everyone,
for our project we need to evaluate a CoAP proxy with a simulated network of 15.4 server nodes. My idea is to use cooja for doing so the tunslip tool is used as a bridge between the Californium proxy/Californium CoAP clients and a 6LoWPAN network. It works
well, but, it’s required to run the simulation at “human time” because on the proxy side I collect statistics and also because CoAP timeouts are useless if the couple coap client and coap server runs at different speed. (with cooja you can require a simulation
to go as fast as possible ).
I’ve exploited many ways, one of that was to set a “safe” speed up (e.g. 2x human time), tracking the simulation speed time and scale every statistics collected from Californium by that factor. However this methos is not so reliable (cooja can slow down and
accelerate without a reasonable reason).
A second idea (and now comes the question), is to import a Californium element inside cooja.
Basically I would need a new connector that has to put the UDP packet inside a IPV6 segment and then inside a 15.4 frame. This packet has to be passed to the cooja interface for sending packet. And this seems easy. My problem is, how to
correctly handle timers? E.g. the retransmission timer? I know that cooja allows a thread to become an observer of every simulated millisecond. Do you think is feasible to organize a “coojaStack” in which time elapses based on such observer? Do you have any
idea or hints on how and where to start?
My hope is to save a lot of time by simulating in such a way.
Simone Bolettieri – Research Fellow at the Institute of Informatics and Telematics (IIT)-CNR in Pisa
