bgp

BGP Notification Error Codes

Error codes and subcodes carried in the Border Gateway Protocol (BGP-4) NOTIFICATION message, sent when a speaker detects an error condition and is about to close the session. Defined in the base BGP-4 specification and extended by several companion RFCs.

40 codes

references rfc-editor.org/rfc/rfc4271 rfc-editor.org/rfc/rfc4271 iana.org/assignments/bgp-parameters/bgp-parameters.xhtml

· All codes 40 codes

1-1 Message Header Error: Connection Not Synchronized The Marker field of the BGP message header did not contain the expected value, indicating the connection is out of sync with the peer.
1-2 Message Header Error: Bad Message Length The Length field of the message header specified a value that is either less than the minimum (or greater than the maximum) allowed for the message type, or that is inconsistent with the message body received.
1-3 Message Header Error: Bad Message Type The Type field of the message header contained a value that is not one of the recognized BGP message types (OPEN, UPDATE, NOTIFICATION, KEEPALIVE, or ROUTE-REFRESH).
1 Message Header Error The receiver found a problem in the fixed-size BGP message header shared by all message types — an out-of-sync marker, an invalid length, or an unrecognized type. See code entries 1-1 through 1-3 for the specific reason.
2-1 OPEN Message Error: Unsupported Version Number The BGP Version field in the OPEN message proposed a protocol version the receiver does not support. The Data field of the NOTIFICATION carries the largest, locally supported version number less than the one the peer proposed, so the peer can retry with a compatible version.
2-2 OPEN Message Error: Bad Peer AS The Autonomous System number in the OPEN message does not match the AS the receiver expected to peer with, based on its local configuration.
2-3 OPEN Message Error: Bad BGP Identifier The BGP Identifier field in the OPEN message is syntactically invalid, for example not a unique, properly formatted 4-octet value representing the sender.
2-4 OPEN Message Error: Unsupported Optional Parameter The OPEN message contained an Optional Parameter that the receiver does not recognize or support.
2-6 OPEN Message Error: Unacceptable Hold Time The Hold Time proposed in the OPEN message is unacceptable to the receiver — for example, a nonzero value below the receiver's configured minimum.
2-7 OPEN Message Error: Unsupported Capability The OPEN message's Capabilities Optional Parameter advertised one or more capabilities that the receiver requires but does not support. The Data field lists the offending capabilities, each encoded as it would appear in the OPEN message, so the peer knows what to omit or negotiate differently on retry.
2 OPEN Message Error The receiver found a problem with the contents of a peer's OPEN message — an unsupported version, an unacceptable AS or identifier, or a malformed optional parameter. See code entries 2-1 through 2-7 for the specific reason.
3-1 UPDATE Message Error: Malformed Attribute List The Path Attributes in the UPDATE message could not be parsed as a well-formed attribute list — for example, an attribute appeared more than once.
3-10 UPDATE Message Error: Invalid Network Field A prefix carried in the Network Layer Reachability Information of the UPDATE message is syntactically invalid, for example an address length that does not correspond to a valid prefix.
3-11 UPDATE Message Error: Malformed AS_PATH The AS_PATH attribute is malformed — for example, its segment structure cannot be parsed, or it is inconsistent with the required confederation or aggregation rules.
3-2 UPDATE Message Error: Unrecognized Well-known Attribute The UPDATE message contained an attribute flagged as well-known that the receiver does not recognize. The Data field carries the unrecognized attribute (type, length, and value).
3-3 UPDATE Message Error: Missing Well-known Attribute The UPDATE message did not include a well-known attribute that is mandatory. The Data field carries the type of the missing attribute.
3-4 UPDATE Message Error: Attribute Flags Error The flags octet of a path attribute (Optional, Transitive, Partial, Extended Length bits) does not match what is defined for that attribute type, or is inconsistent with the attribute's content.
3-5 UPDATE Message Error: Attribute Length Error The Attribute Length field of a path attribute does not match the actual length of the attribute's value, or is inconsistent with the overall UPDATE message length.
3-6 UPDATE Message Error: Invalid ORIGIN Attribute The value of the ORIGIN attribute is not one of the defined values (IGP, EGP, or INCOMPLETE).
3-8 UPDATE Message Error: Invalid NEXT_HOP Attribute The NEXT_HOP attribute contains an invalid value — for example, an IP address the receiver knows is not a valid next hop, such as 0.0.0.0, a loopback address, or a multicast address.
3-9 UPDATE Message Error: Optional Attribute Error An optional attribute in the UPDATE message is malformed, so its value cannot be interpreted correctly.
3 UPDATE Message Error The receiver found a problem with the contents of an UPDATE message — a malformed, missing, or invalid path attribute, or a malformed prefix in the Network Layer Reachability Information. See code entries 3-1 through 3-11 for the specific reason.
4 Hold Timer Expired No BGP message (UPDATE or KEEPALIVE) was received from the peer within the negotiated Hold Time, so the session is being torn down. Has no defined subcodes; the Error Subcode field is always zero (Unspecific).
5-0 Finite State Machine Error: Unspecified Error An unexpected message was received for the current session state, but none of the more specific per-state subcodes applies.
5-1 Finite State Machine Error: Receive Unexpected Message in OpenSent State A message other than an OPEN, NOTIFICATION, or the expected keepalive was received while the session was in the OpenSent state.
5-2 Finite State Machine Error: Receive Unexpected Message in OpenConfirm State A message other than a KEEPALIVE or NOTIFICATION was received while the session was in the OpenConfirm state.
5-3 Finite State Machine Error: Receive Unexpected Message in Established State A message that violates the expectations of the Established state (for example, a malformed sequencing of UPDATE/KEEPALIVE messages) was received while the session was Established.
5 Finite State Machine Error The peer received a message that is unexpected for the current state of the BGP session's finite state machine. See code entries 5-0 through 5-3 for the specific state in which the unexpected message arrived.
6-1 Cease: Maximum Number of Prefixes Reached The number of prefixes received from the peer reached a locally configured limit, and the session is torn down to protect the receiver's resources.
6-2 Cease: Administrative Shutdown The session was shut down by a local administrative action, for example an operator disabling the peer configuration.
6-3 Cease: Peer De-configured The peer's configuration was removed entirely, so the session is being closed as part of that de-configuration.
6-4 Cease: Administrative Reset The session was reset by a local administrative action, for example an operator clearing the session, distinct from a full shutdown.
6-5 Cease: Connection Rejected An incoming connection from the peer was rejected, for example because a connection to that peer already exists or the peer is not configured.
6-6 Cease: Other Configuration Change A local configuration change other than a full de-configuration (for example, changing a policy or session parameter) required the session to be brought down and re-established.
6-7 Cease: Connection Collision Resolution Two TCP connections were opened between the same pair of BGP speakers at once; this session lost the collision-resolution procedure and is being closed in favor of the other.
6-8 Cease: Out of Resources The local system ran out of resources needed to support the session, such as memory for the routing table, and closed the session to recover.
6-9 Cease: Hard Reset Sent by a speaker that supports Graceful Restart to explicitly request a full session restart rather than a graceful one, so the peer does not preserve stale forwarding state for it.
6 Cease The session is being deliberately torn down for a reason other than a protocol error, such as an administrative action or a resource limit. See code entries 6-1 through 6-9 for the specific reason.
7-1 ROUTE-REFRESH Message Error: Invalid Message Length A ROUTE-REFRESH message carrying a Begin-of-RIB or End-of-RIB marker (Message Subtype 1 or 2) had a body length other than the required 4 octets.
7 ROUTE-REFRESH Message Error The receiver, having negotiated the Enhanced Route Refresh Capability with this peer, found a problem with a received ROUTE-REFRESH message. See code entry 7-1 for the specific reason.