The InfiniBand architecture (IBA) is a new industry-standard architecture for server I/O and interprocessor communication. InfiniBand is very likely to become the de facto standard in a few years. It is being developed by the InfiniBand^SM Trade Association (IBTA) to provide the levels of reliability, availability, performance, scalability, and quality of service (QoS) necessary for present and future server systems. We propose a simple and effective strategy for configuring the IBA networks to provide the required levels of QoS. This is a global frame that allows one to do a different treatment to each kind of traffic based on its QoS requirements. It is based on the correct configuration of the mechanisms IBA provides to support QoS. We also propose a simple algorithm to maximize the number of requests to be allocated in the arbitration table that the output ports have. This proposal is evaluated and the results show that every traffic class meets its QoS requirements