Abstract: A method in a packet switching system for arbitrating access for incoming channels (100÷109) to an outgoing channel (120) so that each channel is constrained within a minimum bandwidth, a maximum bandwidth, and a defined inter-packed delay range by use of a transferable credit value system, including a channel value for each channel, a master value, and selecting one incoming channel (100) to be permitted to transmit a packet through the outgoing channel (120), upon a transmission from one of the incoming channels (100÷109) to the outgoing channel (120) being permitted, changing the credit for that channel and making a corresponding change in the master value. Channels are eligible to transmit packets while they have a channel value within a specified limit. Channel values are reset when the master value falls outside a specified limit.