Comprehensive and Detailed Explanation
BGP Flowspec allows routers to distributetraffic-filtering rulesusing BGP NLRI.
To enable Flowspec, after neighbors are configured, the essential next step is:
✔Activate the Flowspec address-family under BGP
Example:
router bgp 65000
address-family ipv4 flowspec
neighbor X.X.X.X activate
exit-address-family
This enables:
FlowSpec NLRI exchange
Distribution of drop rules (rate-limit, redirect, null route, etc.)
Automatic ACL/class-map/policy-map generation on edge routers
Why the other options are incorrect:
B. Set BGP routing process→ already done when neighbors were configured
C. Activate neighbors→ only makes senseinsidean address-family; flowspec AF must be enabled first
D. Configure route reflector→ optional and not required for Flowspec to operate
Thus, the correct next step isA. Configure Flowspec for the BGP address-family.