Improved network design techniques are provided. More particularly, the
invention provides network design techniques that support fast
restoration. In one aspect of the invention, a technique for designing a
protection capacity to be reserved in a network comprises the following
steps/operations. Link capacities associated with a network topology and
existing working traffic in the network are obtained. Capacity partitions
are determined for links in the network topology. Each of at least a
portion of the capacity partitions comprise a protection capacity portion
and a working capacity portion that equals or exceeds the existing
working traffic on a corresponding link, such that upon a failure on the
link, the working traffic on the link is rerouted over a pre-provisioned
detour path using the protection capacity portion on one or more links on
the detour path. Further, the capacity partition determination
step/operation substantially guarantees protection for existing working
traffic in the network. Still further, the capacity partition determining
step/operation may further substantially guarantee protection for future
working traffic in the network.