1 research outputs found
Conflict-Free Replicated Data Types in Dynamic Environments
Over the years, mobile devices have become increasingly popular and gained improved
computation capabilities allowing them to perform more complex tasks such as
collaborative applications. Given the weak characteristic properties of mobile networks,
which represent highly dynamic environments where users may experience regular involuntary
disconnection periods, the big question arises of how to maintain data consistency.
This issue is most pronounced in collaborative environments where multiple users interact
with each other, sharing a replicated state that may diverge due to concurrency
conflicts and loss of updates.
To maintain consistency, one of today鈥檚 best solutions is Conflict-Free Replicated Data
Types (CRDTs), which ensure low latency values and automatic conflict resolution, guaranteeing
eventual consistency of the shared data. However, a limitation often found on
CRDTs and the systems that employ them is the need for the knowledge of the replicas
whom the state changes must be disseminated to. This constitutes a problem since it is
inconceivable to maintain said knowledge in an environment where clients may leave
and join at any given time and consequently get disconnected due to mobile network
communications unreliability.
In this thesis, we present the study and extension of the CRDT concept to dynamic
environments by introducing the developed P/S-CRDTs model, where CRDTs are coupled
with the publisher/subscriber interaction scheme and additional mechanisms to
ensure users are able to cooperate and maintain consistency whilst accounting for the
consequent volatile behaviors of mobile networks. The experimental results show that
in volatile scenarios of disconnection, mobile users in collaborative activity maintain
consistency among themselves and when compared to other available CRDT models, the
P/S-CRDTs model is able to decouple the required knowledge of whom the updates must
be disseminated to, while ensuring appropriate network traffic values