Name two ways to trigger a BGP update.

• A. A hard reset or a soft reset
• B. A route refresh only
• C. A BGP session restart
• D. A router reload

Answer: (A)

In BGP, updates are driven by changes that require the neighbor’s view of the routing information to be refreshed. The two practical ways to force such an update are restarting the BGP session (hard reset) or performing a soft reset.

A hard reset tears down the BGP TCP session and then re-establishes it. When the session comes back up, both sides exchange a full set of routes again, so every advertised path is refreshed. This is disruptive, but it guarantees a complete refresh of all routing information and policies.

A soft reset keeps the BGP session intact and reprocesses the routes based on current policies. This can trigger updates for changed or re-imported routes without dropping the session, often using a route-refresh mechanism to re-advertise routes as needed. It’s the non-disruptive way to refresh the neighbor’s view when policy changes have occurred.

Route refresh by itself is a specific mechanism used within a soft reset to request a re-advertisement of routes, but it sits under the broader concept of a soft reset. A router reload or a full BGP session restart is more drastic and aligns with the hard reset idea, but the phrase “hard reset or a soft reset” covers the two primary, deliberate methods to force a BGP update.