They introduced an important mechanism of negotiation. Meta-data that describes
the observed data are broadcast to neighbors through advertisement
(ADV). Negotiation helps ensure that only useful information is transmitted
so as to save energy.
SPIN is an event-driven method, which pushes new data to the network
regardless of whether the data will be consumed. Another important datacentric
routing, called directed di?®usion [24], was proposed to di?®use data
243 Chapter 10 Location Service, Info. Dissemination and Object Tracking
Dan-Dan Liu and Xiao-Hua Jia
queries in an on-demand fashion. An interest message is broadcasted by a
sink node through its neighbors when it needs to access data. The sink node
then starts to report back after receiving such an interest message.
The common disadvantage of these three typical protocols is that each
node is required to play a role in every transaction of data accessing, joining
either the write quorum or the read quorum. Lots of problems exist due to
the large amount of tra?±c among nodes.
Gossiping [25] is an alternative to the classic flooding that avoids the
imploding problem and achieves energy e?±ciency through randomization [26],
[27]. However, it disseminates information slowly and cannot even guarantee
the eventual delivery of the data to querying nodes.
3.2 Quorum-Based Method
In [28], the authors discuss a distributed processing system of WSNs that
provides distributed information services on sensed data e?±ciently.
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