In the last few years there has been extensive research activity in the emerging area of
Intermittently Connected Mobile Ad Hoc Networks (ICMANs). By considering the nature of
intermittent connectivity in most real word mobile environments without any restrictions placed
on users' behavior ICMANs are eventually formed without any assumption with regard to the
existence of a end-to-end path between two nodes wishing to communicate. It is different from
the conventional Mobile Ad Hoc Networks (MANETs) which have been implicitly viewed as a
connected graph with established complete paths between every pair of nodes. For the
conventional MANETs mobility of nodes is considered as a challenge and needs to be handled
properly to enable seamless communication between nodes. However to overcome intermittent
connectivity in the ICMANs context mobility is recognized as a critical component for data
communications between the nodes that may never be part of the same connected portion of the
network. This comes at the cost of addition considerable delay in data forwarding since data
are often stored and carried by the intermediate nodes waiting for the mobility to generate the
next forwarding opportunity that can probably bring it close to the destination. Such incurred
large delays primarily limit ICMANs to the applications which must tolerate delays beyond
traditional forwarding delays. ICMANs belong to the family of delay tolerant networks (DTNs).
However the unique characteristics (e.g. self-organizing random mobility and ad hoc based
connection) derived from MANETs distinguish ICMANs from other typical DTNs such as
interplanetary network (IPN) with infrastructure-based architecture. By allowing mobile nodes
to connect and disconnect based on their behaviors and wills ICMANs enable a number of novel
applications to become possible in the field of MANETs. For example there is a growing demand
for efficient architectures for deploying opportunistic content distribution systems over
ICMANs. This is because a large number of smart handheld devices with powerful functions enable
mobile users to utilize low cost wireless connectivities such as Bluetooth and IEEE 802.11 for
sharing and exchanging the multimedia contents anytime anywhere. Note that such phenomenal
growth of content-rich services has promoted a new kind of networking where the content is
delivered from its source (referred to as publisher) towards interested users (referred to as
subscribers) rather than towards the pre-specified destinations. Compared to the extensive
research activities relating to the routing and forwarding issues in ICMANs and even DTNs
opportunistic content distribution is just in its early stage and has not been widely
addressed. With all these in mind this book provides an in-depth discussion on the latest
research efforts for opportunistic content distribution over ICMANs.
