A device to act as a first of a plurality of routing elements of a routing network, comprising: an input port (142, 144), wherein the input port (142, 144) is arranged to receive a message from a first neighbor in the routing network, wherein the routing network further includes a set of sources (102, 103, 104), a primary destination being shared among all of the set of sources (102, 103, 104), and a set of secondary destinations each being an aggregator for messages on the routing network, and the message includes a destination identifier to identify an intended destination selected from the primary destination or the set of secondary destinations; a set of output ports (146, 148) including a primary output port and a set of secondary output ports, wherein the primary output port is arranged to be coupled to a second neighbor that is the primary destination or a routing element that reaches the primary destination, and a secondary output port is arranged to be coupled to a third neighbor that is one of the secondary destinations or a routing element that reaches one or more of the set of secondary destinations; and a control unit, wherein the control unit is arranged to: when the intended destination of the message is a secondary destination (106; 107) of the set of secondary destinations and a secondary output port is in a functional state, select the secondary output port of the set of output ports to deliver the received message to the secondary destination (106; 107), or when the intended destination is the secondary destination (106; 107) and the secondary output port that reaches the secondary destination (106; 107) is in a nonfunctional state, select the primary output port to deliver the received message to the primary destination instead of the secondary destination (106; 107), wherein the routing network includes only one secondary destination (106; 107), and the destination identifier includes only one bit having a binary value of 0 or 1, to indicate whether the intended destination is the primary destination or the secondary destination (106; 107), and wherein the control unit is arranged to determine the intended destination based on the bit. an input port (142, 144), wherein the input port (142, 144) is arranged to receive a message from a first neighbor in the routing network, wherein the routing network further includes a set of sources (102, 103, 104), a primary destination being shared among all of the set of sources (102, 103, 104), and a set of secondary destinations each being an aggregator for messages on the routing network, and the message includes a destination identifier to identify an intended destination selected from the primary destination or the set of secondary destinations; a set of output ports (146, 148) including a primary output port and a set of secondary output ports, wherein the primary output port is arranged to be coupled to a second neighbor that is the primary destination or a routing element that reaches the primary destination, and a secondary output port is arranged to be coupled to a third neighbor that is one of the secondary destinations or a routing element that reaches one or more of the set of secondary destinations; and a control unit, wherein the control unit is arranged to: when the intended destination of the message is a secondary destination (106; 107) of the set of secondary destinations and a secondary output port is in a functional state, select the secondary output port of the set of output ports to deliver the received message to the secondary destination (106; 107), or when the intended destination is the secondary destination (106; 107) and the secondary output port that reaches the secondary destination (106; 107) is in a nonfunctional state, select the primary output port to deliver the received message to the primary destination instead of the secondary destination (106; 107), when the intended destination of the message is a secondary destination (106; 107) of the set of secondary destinations and a secondary output port is in a functional state, select the secondary output port of the set of output ports to deliver the received message to the secondary destination (106; 107), or when the intended destination is the secondary destination (106; 107) and the secondary output port that reaches the secondary destination (106; 107) is in a nonfunctional state, select the primary output port to deliver the received message to the primary destination instead of the secondary destination (106; 107), wherein the routing network includes only one secondary destination (106; 107), and the destination identifier includes only one bit having a binary value of 0 or 1, to indicate whether the intended destination is the primary destination or the secondary destination (106; 107), and wherein the control unit is arranged to determine the intended destination based on the bit.