BATTLEFIELD DIGITAL FORENSICS

In a wireless ad-hoc network, all the nodes are interconnected by single-hop or multi-hop wireless connections.
There is no centralised control or base station to coordinate the behaviour of each node in the network. As a
result, each node must be self-configurable in order to adapt to various network topologies. Nodes can assist in
transmitting packets from a source to a destination through wireless connections in a fully peer-to-peer
fashion. At the same time, because of the wireless connections, service coverage and bandwidth availability
become critical issues in the wireless channels.
A main feature of ad-hoc networks is that all the nodes in the network have the freedom to move around,
which causes the network topology to change dynamically and unpredictably.
Mobile ad-hoc networks that include specific gateway nodes towards other networks (such as cellular, satellite,
or WiMAX) can be called hybrid mobile ad-hoc networks [8]. Some ad-hoc network routing protocols provide
delay-tolerant (or disruption-tolerant) networking (DTN), and this could be used to create an ad-hoc mobile file
system. DTN works over existing protocol stacks in various network architectures and provides a store-andforward
functionality [9]. One use case for DTN is military battlegrounds where the disconnection may be
caused by mobility of vehicles, forces and devices, environmental factors, intentional electronic jamming done
by the enemy, or by the loss of the acquisition vector. DTN can be considered as one technique used in
opportunistic networks. Opportunistic networking is more flexible than DTN, because opportunistic networks
may also contain other communication techniques than protocols used in the internet, and each single node
acts as a gateway 5 [10].
Figure 5. DTN example of store-and-forward functionality [11].
Use cases presented in Figure 6 combine a few example techniques adopted in hybrid mobile ad hoc networks,
DTN-based networks, and in opportunistic networking. The idea of the figure is based on figures of [11], but
includes more detail. In the figure, source S1 sends a message to destination D1, source S2 sends a message to
D2, and source S3 sends a message to D3. M2 is connected into a wireless ad-hoc network which is moving
with it. Originally the ad-hoc network is larger, containing a number of static wireless sensors; when the M2
moves far enough away from them, the wireless ad-hoc network is distributed into two sections. DTN allows
transferring data nodes that do not have routes between each other, for example if they are located in two
separate ad-hoc networks.
5 Note that ‘gateway’ here does not mean the same as gateway in hybrid mobile ad-hoc networks.
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