Internet Engineering Task Force (IETF) J. Snijders
Request for Comments: 8203 NTT
Updates: 4486 J. Heitz
Category: Standards Track Cisco
ISSN: 2070-1721 J. Scudder
July 2017 BGP Administrative Shutdown Communication
This document enhances the BGP Cease NOTIFICATION message
"Administrative Shutdown" and "Administrative Reset" subcodes for
operators to transmit a short freeform message to describe why a BGP
session was shutdown or reset. This document updates RFC 4486.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
The Cease NOTIFICATION message with a Shutdown Communication is
encoded as below:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
| Error Code 6 | Subcode | Length | ... \
/ ... Shutdown Communication ... /
Subcode: the Error Subcode value MUST be one of the following
values: 2 ("Administrative Shutdown") or 4 ("Administrative
Length: this 8-bit field represents the length of the Shutdown
Communication field in octets. The length value MUST range from 0
to 128 inclusive. When the length value is zero, no Shutdown
Communication field follows.
Shutdown Communication: to support international characters, the
Shutdown Communication field MUST be encoded using UTF-8. A
receiving BGP speaker MUST NOT interpret invalid UTF-8 sequences.
Note that when the Shutdown Communication contains multibyte
characters, the number of characters will be less than the length
value. This field is not NUL terminated.
Mechanisms concerning the reporting of information contained in the
Shutdown Communication are implementation specific but SHOULD include
methods such as Syslog [RFC5424].
3. Operational Considerations
Operators are encouraged to use the Shutdown Communication to inform
their peers of the reason for the shutdown of the BGP session and
include out-of-band reference materials. An example of a useful
Shutdown Communication would be:
"[TICKET-1-1438367390] software upgrade; back in 2 hours"
"[TICKET-1-1438367390]" is a ticket reference with significance to
both the sender and receiver, followed by a brief human-readable
message regarding the reason for the BGP session shutdown followed by
an indication about the length of the maintenance. The receiver can
now use the string 'TICKET-1-1438367390' to search in their email
archive to find more details.
4. Error Handling
If a Shutdown Communication with an invalid Length value, or an
invalid UTF-8 sequence is received, a message indicating this event
SHOULD be logged for the attention of the operator. An erroneous or
malformed Shutdown Communication itself MAY be logged in a hexdump
5. IANA Considerations
IANA references this document (in addition to [RFC4486]) for subcodes
"Administrative Shutdown" (2) and "Administrative Reset" (4) in the
"Cease NOTIFICATION message subcodes" registry under the "Border
Gateway Protocol (BGP) Parameters" group.
6. Security Considerations
This document uses UTF-8 encoding for the Shutdown Communication.
There are a number of security issues with Unicode. Implementers and
operators are advised to review Unicode Technical Report #36 [UTR36]
to learn about these issues. UTF-8 "Shortest Form" encoding is
REQUIRED to guard against the technical issues outlined in [UTR36].
As BGP Shutdown Communications are likely to appear in syslog output,
there is a risk that carefully constructed Shutdown Communication
might be formatted by receiving systems in a way to make them appear
as additional syslog messages. To limit the ability to mount such an
attack, the BGP Shutdown Communication is limited to 128 octets in
Users of this mechanism should be aware that unless a transport that
provides integrity is used for the BGP session in question, a
Shutdown Communication message could be forged. Unless a transport
that provides confidentiality is used, a Shutdown Communication
message could be snooped by an attacker. These issues are common to
any BGP message but may be of greater interest in the context of this
proposal since the information carried in the message is generally
expected to be used for human-to-human communication. Refer to the
related considerations in [RFC4271] and [RFC4272].
Users of this mechanism should consider applying data minimization
practices as outlined in Section 6.1 of [RFC6973] because a received
Shutdown Communication may be used at the receiver's discretion.
The authors would like to gratefully acknowledge Tom Scholl, David
Freedman, Jared Mauch, Jeff Haas, Peter Hessler, Bruno Decraene, John
Heasley, Peter van Dijk, Arjen Zonneveld, James Bensley, Susan Hares,
Saku Ytti, Lou Berger, Alvaro Retana, and Adam Roach.
The authors would like to thank Enke Chen and Vincent Gillet for
their work on [RFC4486] and granting the related rights to the IETF
Trust per BCP 78.
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