This final degree project presents the different Layer 2 solutions that increase the scalability of the Ethereum blockchain, as a solution to the Blockchain Trilemma proposed by V. Buterin: the difficulty of current blockchain systems to simultaneously address the problems of scalability, decentralization and security. In particular, the optimistic rollups solution is presented as the current most promising alternative to increase the scalability without compromising decentralization nor security of the system. To do so, different components that define this solution will be studied, as well as its flow of information and execution. Furthermore, other essential technical elements required by rollup systems to work properly will be presented. The main functionalities of optimistic rollups are explained in detail. Both efficiency and benefits are justified through computations based on real data. Additionally, the Optimism testnet is introduced, which is the experimental environment used to carry out the different types of tests and thus to evaluate the performance of optimistic rollups in different contexts. Finally, the results obtained from the different experiments are meticulously analyzed and compared with data from the Ethereum mainnet in order to demonstrate the performance of this Layer 2 solution.