Explains how prefix aggregation matches multiple subnets with one explicit prefix-list entry and how catch-all entries behave in different route-control contexts.
Aggregation in an explicit prefix list matches a base prefix and the more-specific subnets within a configured mask range.
To advertise a bridge domain subnet through an L3Out, set the subnet scope to Advertised Externally.
Catch-All Prefix Aggregation Behavior
Configuring prefix 0.0.0.0/0 with aggregation enabled generates the equivalent prefix-list entry 0.0.0.0/0 le 32. The generated entry behaves differently in the following route-control contexts:
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Aggregate Export on an L3Out subnet: The route map matches routes learned from dynamic routing protocols. It does not match bridge domain subnets or directly connected networks.
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Explicit prefix list in the
default-exportroute map: The route map matches all routes, including bridge domain subnets and directly connected networks.
Route Map with a Catch-All Entry
In this scenario, route map rpm_with_catch_all contains a catch-all entry. When the system exports the bridge domain subnet, the route-map policies do not apply to that subnet. The route map processes the transit route without affecting the static route.
Default Export Route Map
In this scenario, the default-export route map contains the explicit catch-all prefix. The route map matches all routes, including bridge domain subnets and directly connected networks.