Unidirectional Link-State Routing with Propagation Control

Unidirectional links can occur in wireless networks and mixed-media networks. However, the vast majority of routing algorithms proposed to date require bidirectional links to operate. We present an efficient link-state routing algorithm, which we call ULPC, that operates with unidirectional links. ULPC is based on the concept of “inclusive cycle” of a link, which is the distance that link-state updates about the link must propagate to ensure correct routing within the network. ULPC incrementally disseminates and selectively utilizes unidirectional link-state information to build correct routing tables. ULPC is verified to be correct. Simulations on a 20-node network with unidirectional links show that ULPC is superior over the traditional link-state routing algorithms relying on topology broadcast. Keywords— Link-state routing, unidirectional link, inclusive cycle.