There is no doubt that networks are becoming increasingly heterogeneous and future internetworks will likely interconnect different types of networks including wired, infrastructure-based wireless as well as infrastructure-less wireless networks, a.k.a., multi-hop mobile ad-hoc networks (or MANETs). Integrating MANETs to infrastructure-based networks (wired or wireless) allows network coverage to be extended to regions where infrastructure deployment is sparse or nonexistent as well as a way to cope with intermittent connectivity. However, to date there are no comprehensive solutions that integrate MANETs to infrastructure-based networks. In this paper, we introduce a message delivery framework, MeDeHa++ that is able to bridge together infrastructure-based and infrastructure-less networks. Through extensive simulations, we demonstrate the benefits of MeDeHa++, especially in terms of the extended coverage it provides as well as its ability to cope with arbitrarily long-lived connectivity disruptions. Another important contribution of this work is to deploy and evaluate our message delivery framework on a real network testbed as well as conduct experiments in "hybrid" scenarios running partly on simulation and partly on real nodes. © 2011 IEEE.