5.4 ANYCASTING WITH GUARANTEED DELIVERY
In the anycasting problem, a source node wants to send a message to any node that belongs to a given set of destinations. In the context of IP networks, this problem was first formulated in the RFC 1546 as follows: “the host transmits a datagram to an anycast address and the Internetwork is responsible for providing best-effort delivery of the datagram to at least one, and preferably only one” (this was later reformulated in RFC 2373, in the context of IPv6). However, a number of articles refer to the anycasting problem while solving a different problem. For example, in Chen et al. (2004) and Jeon and Kesidis, (2007), the term anycasting corresponds to the first stage of some geocasting protocols (see Section 5.2), which consists in reaching any node inside a given geographical region.
In the present section, we consider that anycasting typically occurs when a sensor wants to report its data to an actuator, but does not care about which one of them will effectively receive the report. Such a protocol should try to reach the actuator closest to the reported event in order to minimize the energy consumption induced by the report. Finally, actuators must be considered by the protocol as possibly scattered all over the network.
While a number of anycasting protocols were designed for wired networks (Wu et al., 2007), only a few have been designed for wireless networks, and most of them are adaptations of an anycast routing for wired networks ...