언제나 ing

This article is just my understanding about two techniques.
Caching and Replica allocation technique are the famous technique
to improve data accessibility in distributed sytem.
And they are also used in Mobile Ad hoc Network which is my reseach area.
So this description is aspect of MANET(Mobile Ad Hoc Netowrk).

In fact, the aim of two technique is similar although there are critial difference between them.

Caching : The node which is a member of network store the data temporarily by their discretion.
                So whether to cache data or not depends on the node itself.
                When using caching technique, the node need not to request data which is stored own storage.
                The query delay will be decreased and accessbility will be increased
                when the node can't access to data source.
                That is reason enough why we use caching technique.

Replica allocation : Replica allocation technique is also very benenfit technology.
                                 The nodes are stored data proactively.
                                 Participating replica allocation phase means that  a node promise other nodes
                                 which also participate in replica allocation phase to have replicated data implicitly.
                                 When using replica allocation techinique, the node can retrieve from a nearby node
                                 which has the replicated data instead of data source.
                                 It also reduce query delay and increase data accessibility
                                 when a node can't access data source.