An enhanced virtual router redundancy protocol for manipulating master router selection within a network is disclosed. The use of a priority control policy and priority values take into account conditions and events that may distinguish the desirability of one router over another. Explicit priority values may be specified to indicate the explicit priority of a particular router instance. Delta priority values may also be used to decrement or increment a base priority for a particular router instance. By using priority control policies and priority values to select a master, improved control, management, and manipulation of virtual router instances over a particular IP core network interface are enabled.