Backbone networks today are usually designed for a single traffic matrix. Due to considerations such as future growth and fault tolerance, links are highly over-provisioned, and the typical utilization in the backbone is very low. But despite over-provisioning, the number of traffic matrices that can be supported by the network is very small.

Valiant load-balancing uses a different approach. It assumes knowledge of the aggregate traffic rate at the nodes and can support all traffic matrices by load-balancing over the whole network. This architecture has many advantages. It is robust against failures, because the working paths can quickly take over when failures happen. It is also efficient. In a homogeneous network, VLB is proved to be the most efficient architecture in terms of total link capacity required to support all traffic matrices. In a general network, VLB is proved to be a 1.2-approximation of the optimal.