A communications node connected to a packet-switched data input/output network, such as an InfiniBand® network, has a plurality of processing cores on which a subnet management agent may be run. The subnet management agent processes management instructions relating to node configuration. In the invention, the processing core running the subnet management agent may be dynamically changed by one or more of the processing cores in the node. The processing cores may include a host processor, a service processor and an embedded processor, dedicated to a host channel adapter, which provides a communications interface between the network and the node. Various methods may be used to move the subnet management agent, including the use of a register to which one or more of the processing cores may write, and in which is stored an indication of which processing core is currently running the subnet management agent.