Automatic Summarization of Routes

By default, all routes redistributed into BGP from an IGP are automatically summarized to their natural network masks.

auto-summary

Use to reenable automatic summarization of routes redistributed into BGP.
Automatic summarization is enabled by default. However, creating an address family for a VRF automatically disables automatic summarization for that address family.
This command takes effect immediately.
Use the no version to disable automatic summarization of redistributed routes.
See auto-summary.