Scalable and fault-tolerant link state routing protocol for packet-switched networks

A distributed Link-State Routing (LSRP) system in a packet switch having external communication ports has a first card executing Update process of the LSRP, making database updates, a second card executing Decision process (Shortest Path First (SPF)) of the LSRP, and a communication fabric coupling the cards with each other and the external ports. The LSRP may be an IS-IS system. In some embodiments there are additional cards involved, and the distribution of Link-State functions is over a set of multiple cards. Also in some embodiments there is a Location Service (LS) controller monitoring and configuring cards in the system.