!!! Overview[1]
[{$pagename}] is defined in theoretical computer science, the [{$pagename}], also named Brewer's theorem after computer scientist Eric Brewer, states that it is impossible for a distributed computer system to simultaneously provide more than two out of three of the following guarantees: 
* [Consistency]
* [Availability]
* [Partition] tolerance - Defined as __network failure__ of [network] [partition]

[Database] systems designed with traditional [ACID] guarantees in mind such as [RDBMS] choose [consistency] over [availability], whereas systems designed around the [BASE] philosophy, common in the [NoSQL] movement for example, choose [availability] over [consistency].

!! Explanation
No distributed system is safe from network failures, thus network partitioning generally has to be tolerated. In the presence of a [partition], one is then left with two options: [consistency] or [availability]. 

When choosing [consistency] over [availability], the system will return an error or a time out if particular information cannot be guaranteed to be up to date due to network partitioning. 

When choosing [availability] over [consistency], the system will always process the query and try to return the most recent available version of the information, even if it cannot guarantee it is up to date due to network partitioning.[4]

In the absence of __network failure__ – that is, when the [Distributed Data Store] is running normally – both [availability] and [consistency] can be satisfied.

[{$pagename}] is frequently misunderstood as if one had to choose to abandon one of the three guarantees at all times. In fact, the choice is really between [consistency] and [availability] for when a [partition] happens only; at all other times, no trade-off has to be made.

The [PACELC theorem] builds on [{$pagename}] by stating that even in the absence of [partitioning|Partition], another trade-off between [latency] and [consistency] occurs.

!! More Information
There might be more information for this subject on one of the following:
[{ReferringPagesPlugin before='*' after='\n' }]
----
* [#1] - [CAP_theorem|Wikipedia:CAP_theorem|target='_blank'] - based on information obtained 2017-04-10