Scalable routing policy construction using dynamic redefinition of routing preference value

摘要

In general, techniques are described to dynamically redefine a preference value used during route resolution. A network device, such as a router, may implement the techniques to improve a usability aspect of the router. The router may comprise an interface card that receives messages describing one or more of a plurality of routes. The router may also include a control unit that stores data defining a policy. The policy may comprise rules by which the router determines the preference value for one of the plurality of routes. The policy dynamically redefines the preference value as two or more bit fields rather than viewing the preference value as an integer value. The control unit further sets each of the two or more bit fields of the local preference value in accordance with the policy and associates the at least one of the routes with the determined local preference value.