A communication system (5) comprises a first network (10) including a source (11) arranged to transmit data and a second network (30) including a destination (31) arranged to receive the data. Interruptions in communication between the source and destination are reduced by providing a first primary node (12) and a first secondary node (13) in the first network (10), and a second primary node (32) and a second secondary node (33) in the second network (30). First and second sets of primary routes (14 and 34) and secondary routes (18 and 36) are provided within the first and second networks to facilitate delivery of data to various nodes.