In a communication network comprising nodes and links between the nodes, a controller node disseminates routing information including nodal routing tables. The invention also relates to devices for carrying out such methods. Alternatively, the PND may include a three-dimensional magnetic detector and a magnetic calibration module for determining an ambient magnetic field calibration value representing immediate surroundings of the PND. The processor occupancy may be fixed at some value and the calling capacity of the base station is determined from the determined relationship between processor occupancy and calling rates. The light emitting device includes a semiconductor layer, and a light extracting layer arranged on the semiconductor layer and made of a material having a refractive index equal to or higher than a reflective index of the semiconductor layer. The invention further comprises a control device for controlling the stimulation device to stimulate the cardia sphincter.