Error Codes and Related Error Sub-codes

FIGURE 8 . 7 NOTIFICATION message format
Error Code Error Sub-code Data
248 Chapter 8  Border Gateway Protocol
TABLE 8 . 3 Error Codes and Related Error Sub-codes
Error Code
Number Type
Error Sub-code
Number Type
1 Message header error
1 Connection Not Synchronized
2 Bad Message Length
3 Bad Message Type
2 OPENmessage error
1 Unsupported Version Number
2 Bad Peer AS
3 Bad BGP Identifier
4 Unsupported Optional Parameter
5 Authentication Failure
6 Unacceptable Hold Timer
7 Unsupported Capability
3 UPDATEmessage 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
11 Malformed AS_PATH
4 Hold Timer expired
5 Finite State
Machine error
6 Cease

The Cease error is simply any other error than the ones listed.
Now that you have a thorough understanding of the different message types BGP uses, let’s
go ahead and take a look at how all of this comes together.