BGP Notification Message

NOTIFICATION messages are used to signal when something is wrong with the BGP session. A NOTIFICATION will be sent when any of the following occurs:

1. An unsupported option is sent in an OPEN message.
2. A peer fails to send an update or keepalive

When an error is detected, the BGP session is closed.

Notification Message Format

Error code (8 bits)	Error Subcode	data
data

Notification Error Codes

ERROR CODE		ERROR SUBCODE
1	Message Header Error	1 - Connection Not Syncrhonized 2 - Bad Message Length 3 - Bad Message Type
2	OPEN message error	1 - Unsupported Version 2 - Bad Peer AS 3 - Bad BGP Identifier 4 - Unsupported Optional Parameter 5 - Authentication Failure 6 - Unacceptable Hold Time
3	UPDATE Message Error	1 - Malformed Attribute List 2 - Unrecognized well-known attribute 3 - Missing Well-Known Attribute 4 - Attribute Flags Error 5 - Attribute Length Error 6 - Invalid Origin Attribute 7 - AS routing loop 8 - Invalid NEXT_HOP attribute 9 - Optional Attribute Error 10 - Invalid Network Field
4	Hold Timer Expired	No Subcodes
5	Finite State Error	No Subcodes
6	Cease	No Subcodes

 

 

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