FIRE, the Flexible Intra-AS Routing Environment, is an interior gateway routing protocol that allows traffic to be routed based on a set of routing algorithms. Like OSPF, FIRE is a link-state routing protocol, but rather than advertising a single metric as OSPF does, a FIRE router will advertise a series of property values, such as cost and bandwidth. Properties can be configured by an operator, or can be a value determined at run time. Multiple forwarding tables are generated from these properties. A set of filters maps incoming IP packets onto the appropriate forwarding table.