Whether static, dynamic, or policy-based routing is used, the algorithm used by the IP layer to select a route from a route table is the same. Route selection occurs in the following order:
Multiple equal-cost routes are allowed for static, dynamic, and policy-based routing. Table 1 and Multiple equal-cost routes provide additional information about the use of multiple equal-cost routes.
In the absence of policy-based routing, the IP layer routes traffic by searching the main route table for the most specific route known, using the selection order described. If policy-based routing is being used, the IP layer routes traffic according to the policy defined for the traffic. For more information about how the IP layer routes traffic when policy-based routing is being used, see Policy-based routing.