Which two statements describe the purpose of a BGP notification message? (Choose two.)

A BGP Notification message is used to signal a fatal error condition to a BGP peer. When a BGP speaker sends or receives a Notification message, it immediately terminates the BGP session and removes all associated routing entries. The message contains an Error Code and an Error Subcode that explicitly report the specific reason for the error and the subsequent session closure.

A: This describes a BGP UPDATE message, which is used to advertise or withdraw routes while keeping the session active.

D: This describes a BGP Route Refresh message, which requests a re-advertisement of routes without tearing down the session.

- RFC 4271, "A Border Gateway Protocol 4 (BGP-4)", Section 4.5 (NOTIFICATION Message Format) and Section 6.7 (Notification processing). https://doi.org/10.17487/RFC4271

- Juniper Networks TechLibrary, "BGP Message Types" (Understanding BGP Messages).