In BGP, Notification messages are used to request peers to resend routing information after routing policies are changed.

The statement is incorrect. In BGP, a Notification message is used to signal a fatal error condition to a peer. Upon sending or receiving a Notification message, the BGP session is immediately terminated. The mechanism used to request a peer to resend its routing information, typically after a local routing policy change, is the Route Refresh capability, which utilizes a ROUTE-REFRESH message. This allows for dynamic policy application without disrupting the BGP session.

The "True" option is incorrect because it fundamentally misrepresents the purpose of a BGP Notification message. Ascribing the function of requesting route updates to the Notification message is a critical misunderstanding of BGP error handling versus its route policy update mechanisms. Notification messages are for terminating sessions due to errors, not for gracefully requesting updates.

1. IETF RFC 4271

"A Border Gateway Protocol 4 (BGP-4)":

Section 4.5

"NOTIFICATION Message Format": "A NOTIFICATION message is sent when an error condition is detected. The BGP connection is closed immediately after it is sent." This source defines the primary purpose of a Notification message as error signaling followed by connection termination.

2. IETF RFC 2918

"Route Refresh Capability for BGP-4":

Abstract: "This document defines a new BGP message

the ROUTE-REFRESH message

that allows a BGP speaker to request a BGP peer to re-advertise its Adj-RIB-Out to the speaker. This facility can be used when the inbound routing policy of the speaker has been changed." This RFC explicitly introduces the ROUTE-REFRESH message for the exact purpose described in the question.

3. Huawei HCIP-Datacom-Core Technology V1.0 Training Material:

Chapter: BGP Fundamentals

Section: BGP Message Types: This official training material specifies that a Notification message is sent to a peer when an error is detected on a BGP device

causing the BGP connection to be torn down. It separately describes the Route-Refresh message as the mechanism to request a peer to resend its routing information.