A method and apparatus for rerouting traffic in a computer network select a routing element, apply a subnet mask to an interface address of the routing element to generate subnet addresses, determine the address of neighboring elements from the subnet addresses, and obtain configuration information from the neighboring elements. Network topology is determined from the configuration information, a link in the network topology is selected, and a cost associated with the link is modified. The modified cost renders the link less desirable for routing. A method and apparatus for determining the address of neighboring routing elements in a computer network, combine a subnet mask and interface address associated in a bitwise AND operation to generate subnet addresses, disregard the highest and lowest subnet addresses and the address of the selected routing element from the subnet addresses, and identify the remaining subnet address as associated with the neighboring routing element.