Message ferrying is a networking paradigm where a special node, called a message
ferry, facilitates the connectivity in a mobile ad hoc network where the nodes are sparsely deployed. One of the key challenges under this
paradigm is the design of ferry routes to achieve certain properties of end-to-end connectivity, such as, delay and message loss among the
nodes in the ad hoc network. This is a difficult problem when the nodes in the network move arbitrarily.  As we cannot be certain of the
location of the nodes, we cannot design a route where the ferry can contact the nodes with certainty. Due to this difficulty, prior work has
either considered ferry route design for ad hoc networks where the nodes are stationary, or where the nodes and the ferry move pro-actively
in order to meet at certain locations. Such systems either require long-range radio or disrupt nodes' mobility patterns which can be dictated
by non-communication tasks. We present a message ferry route design algorithm that we call the Optimized Way-points, or OPWP, that generates
a ferry route which assures good performance without requiring any online collaboration between the nodes and the ferry. The OPWP ferry route
comprises a set of way-points and waiting times at these way-points, that are chosen carefully based on the node mobility model. Each time
that the ferry traverses this route, it contacts each mobile node with a certain minimum probability. The node-ferry contact probability in
turn determines the frequency of node-ferry contacts and the properties of end-to-end delay.  We show that OPWP consistently outperforms
other naive ferry routing approaches. 

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{\bf Categories and Subject Descriptors:} 
C.2.1 {[Network and Architecture Design]}: {Wireless Communication.}

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{\bf General Terms:} Algorithms, Design, Performance.

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{\bf Keywords:} {Delay \& Disruption Tolerant Networks, 
Mobile Ad hoc Networks, Sparse Networks, Mobility Models.}