Protocols for Secure Communication in Wireless Sensor Networks

6.2. Basic Interleaved Authentication 171
Authentication code overhead
1e+06
100000
10000
Flood
Tree
1000
6 8 10 12 14 16 18 20 22 24 26 28
Average neighbourhood size
Figure 6.5: Total Canvas message overhead when using broadcast-based flooding vs. flooding
over a tree structure. The difference amounts to an order of magnitude
Content-Based Routing
The main idea of content-based routing is to forward a message only to those
nodes, which have stated an interest that matches the type of content the message
carries [35]. This kind of data dissemination is especially suited for environments
in which the sources and receivers of messages frequently change,
and where there is no need for a mutual relationship between a source and the
receivers. A good metaphor of this kind of data dissemination is the spreading
of rumors: The exact source of a rumor is often unknown, and everybody can
either act on the message the rumor conveys, tell it to others, or simply ignore it.
This simplicity is advantageous in large-scale sensor networks. Consequently,
a protocol for content-based data dissemination in sensor networks has been
proposed that builds on this idea [31]. The main idea of “rumor routing” is
that a message source distributes an event notification over a limited number of
(random) paths. Any node interested in a certain kind of events releases a query
that is forwarded along a (also random) path through the network. As soon as
the query hits a node that is part of a matching event path, which happens with
high probability, a path between source and sink can be established.
Rumor routing builds event and query paths randomly, i.e. at each hop, the
next hop is determined by randomly selecting a node from the set of neighbours.
The extension to a k-neighbourhood and adding Canvas authentication