Disclosed is arrangement (101, 102, 110) for routing data packets designated for a particular destination (103) from a packet switch (114) through a circuit switch (120). The packet switch includes a plurality of output links (152, 153) connected to the circuit switch and a memory (209) for storing the identity of the output links designated for use to a particular destination. The circuit switch has a plurality of channels (190) to the particular destination and a switching network (121) for interconnecting an equal number of the channels and the designated output links. Included in the arrangement is a circuit allocator (110) that monitors the use of each of the designated links. When the overall use of the designated output links is greater than an upper threshold, the allocator causes the packet switch to increase the number of links designated for use to the particular destination and subsequently causes the circuit switch to correspondingly increase the number of channels interconnecting with the output links designated for use to the particular destination. The number of designated output links is similarly decreased when the designated overall use of the output links falls below a lower threshold. A predetermined algorithm is used to determine the upper and lower thresholds for each number of output links designated for use to the particular destination.