This document summarizes a data-muling protocol for industrial wireless sensor networks. It presents the D&U protocol which allows motes to discover each other and update data when a mobile mule is in range. The protocol aims to address challenges of resource constraints, dynamic topologies, and internet integration. An evaluation of the protocol on SunSPOT motes found it can increase the number of supported motes and their battery life compared to traditional approaches. Ongoing work looks to extend these results to other wireless protocols.