Abstract: A routing device for routing streams at a node in a packet transmission network receives a stream request, reads specified parameters and any values for loss and delay already incurred at preceding nodes in the network, or specified parameters as modified to take account of loss and delay already incurred at preceding nodes in the network, to determine in conjunction with existing streams already being handled by the routing device whether to accept or reject the stream, allocates one or more buffers to the stream if the stream request has been accepted, transmits the stream request with modified values for loss and delay, or with modified parameters to take account of loss and delay incurred at this and preceding nodes in the network if the stream request has been accepted, and returns a fail signal if the stream request has been rejected.