In most of the cases, the Global Resource has actual connection for connecting to data resource. The generation of connection is generally said to be a high cost process.
Hence, the connection generated once will be pooled(accumulated) and when necessary the connection will be re-used, thereby the generation cost can be kept low. The mechanism used to pool the actual connection this way is called as "component pool".
* For details, please refer to "Global Resource" in online help.