Telecom operators and vendors predict that mobile networks will suffer a serious IP traffic explosion in the very near future. Besides designing, standardizing and deploying novel architectures like LTE/EPC, also radio access and core network technologies of existing communication systems must be extended in order to make them able to serve the expected traffic demands within limited expenditure growth. In this paper we present the implementation and real-life testbed evaluation results of a special technique aiming to enhance existing 3G/UMTS core network mechanisms by enabling GGSN with a dynamic load balancing and load sharing feature. The novelty of this implementation (i.e., its dynamic nature) lies in the fact that it makes the system able to balance the load not only in terms of active mobile nodes or number of serving contexts, but also based on the actual traffic characteristics of active mobile terminals. Our results show that the deployment of such an advanced GGSN scheme could significantly improve throughput and scalability of the overall packet switched domain in operator based 3G/UMTS environments, as it decreases the average packet latency by dynamically choosing between multiple GGSNs according to the real traffic load.