Finding a multi-constrained path is an important potential solution to provide quality of service (QoS) for next-generation networks

where the scalability and routing performance are still open problems.We propose an approach

clustering-based distributed precomputation algorithm

to the problem.Aiming to precompute the routing table with multiple QoS parameters

we introduce the extended distance vector with multiple QoS parameters

based on which the distributed computation greatly decreases the computational complexity on a single node.After dominating path selection is analyzed to omitting numerous dominated paths

a clustering technique is further presented for dominating path aggregation in routing computation.These two techniques in tur n achieve efficient aggregation of the QoS routing table.Simulation results confirm that the proposal not only has low computational complexity

but also achieves high routing performance with good scalability on both QoS parameters and the network scale.The proposal also provides an important basis to further study the interdomain QoS routing.