EuWIn is the " European Laboratory of Wireless Communications for the Future Internet " recently established and funded under the umbrella of the EC FP7 Network of Excellence on Wireless Communications, Newcom♯. The focus of the EuWIn site in Bologna (Italy) is the Internet of Things. One of its scopes is to set up a network composed of 100 radio devices compliant with the IEEE 802.15.4 standard, flexible enough to allow the development and testing of any routing algorithm compatible with such a standard. This paper reports the first comparison of results achieved through an NS-2 simulator developed at LIMOS, CNRS (France), with those of the true network available in Bologna. Results in terms of packet error rate and overhead generated achieved through the two platforms, implementing the same protocol stack, is shown. The differences raised, concerning the practical issues normally not accounted by the simulations, are carefully investigated and discussed.