Dell EMC SmartFabric OS10 User Guide Release 10.5.0

IP prefix-lists control the routing policy. An IP prefix-list is a series of sequential filters that contain a matching criterion and an permit or deny action to process routes. The filters process in sequence so that if a route prefix does not match the criterion in the first filter, the second filter applies, and so on.

A route prefix is an IP address pattern that matches on bits within the IP address. The format of a route prefix is A.B.C.D/x, where A.B.C.D is a dotted-decimal address and /x is the number of bits that match the dotted decimal address.

When the route prefix matches a filter, the system drops or forwards the packet based on the filter’s designated action. If the route prefix does not match any of the filters in the prefix-list, the route drops, an implicit deny.

To configure a prefix-list, use commands in PREFIX-LIST and ROUTER-BGP modes. Create the prefix-list in PREFIX-LIST mode and assign that list to commands in ROUTER-BGP modes.