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draft-idr-8203bis-00.txt
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IDR J. Snijders
Internet-Draft NTT
Obsoletes: 8203 (if approved) J. Heitz
Updates: 4486 (if approved) Cisco
Intended status: Standards Track J. Scudder
Expires: November 1, 2018 Juniper
A. Azimov
Qrator
April 30, 2018
Extended BGP Administrative Shutdown Communication
draft-idr-rfc8203bis-00
Abstract
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 and
obsoletes RFC 8203 by defining an Extended BGP Administrative
Shutdown Communication to improve communication using multibyte
character sets.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 1, 2018.
Snijders, et al. Expires November 1, 2018 [Page 1]
Internet-Draft BGP Shutdown Communication April 2018
Copyright Notice
Copyright (c) 2018 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
(https://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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Shutdown Communication . . . . . . . . . . . . . . . . . . . 2
3. Operational Considerations . . . . . . . . . . . . . . . . . 3
4. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 4
7. Implementation status - RFC EDITOR: REMOVE BEFORE PUBLICATION 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . 5
8.2. Informative References . . . . . . . . . . . . . . . . . 6
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 6
Appendix B. Changes to RFC 8203 . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
It can be troublesome for an operator to correlate a BGP-4 [RFC4271]
session teardown in the network with a notice that was transmitted
via offline methods such email or telephone calls. This document
updates [RFC4486] by specifying a mechanism to transmit a short
freeform UTF-8 [RFC3629] message as part of a Cease NOTIFICATION
message [RFC4271] to inform the peer why the BGP session is being
shutdown or reset.
2. Shutdown Communication
If a BGP speaker decides to terminate its session with a BGP
neighbor, and it sends a NOTIFICATION message with the Error Code
"Cease" and Error Subcode "Administrative Shutdown" or
"Administrative Reset" [RFC4486], it MAY include an UTF-8 encoded
string. The contents of the string are at the operator's discretion.
Snijders, et al. Expires November 1, 2018 [Page 2]
Internet-Draft BGP Shutdown Communication April 2018
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 ... /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1
Subcode: the Error Subcode value MUST be one of the following
values: 2 ("Administrative Shutdown") or 4 ("Administrative
Reset").
Length: this 8-bit field represents the length of the Shutdown
Communication field in octets. 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
Snijders, et al. Expires November 1, 2018 [Page 3]
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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
format.
5. IANA Considerations
Per this document, IANA is requested to reference this document at
subcode "Administrative Shutdown", and at subcode "Administrative
Reset" in the "Cease NOTIFICATION message subcodes" registry under
the "Border Gateway Protocol (BGP) Parameters" group in addition to
[RFC4486] and [RFC8203].
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 255 octets in
length.
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.
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7. Implementation status - RFC EDITOR: REMOVE BEFORE PUBLICATION
This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in RFC7942. The
description of implementations in this section is intended to assist
the IETF in its decision processes in progressing drafts to RFCs.
Please note that the listing of any individual implementation here
does not imply endorsement by the IETF. Furthermore, no effort has
been spent to verify the information presented here that was supplied
by IETF contributors. This is not intended as, and must not be
construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may
exist.
As of today these vendors have produced an implementation of the
Shutdown Communication:
o ...
o ...
o ...
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November
2003, <https://www.rfc-editor.org/info/rfc3629>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>.
[RFC4486] Chen, E. and V. Gillet, "Subcodes for BGP Cease
Notification Message", RFC 4486, DOI 10.17487/RFC4486,
April 2006, <https://www.rfc-editor.org/info/rfc4486>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
Snijders, et al. Expires November 1, 2018 [Page 5]
Internet-Draft BGP Shutdown Communication April 2018
[RFC8203] Snijders, J., Heitz, J., and J. Scudder, "BGP
Administrative Shutdown Communication", RFC 8203,
DOI 10.17487/RFC8203, July 2017,
<https://www.rfc-editor.org/info/rfc8203>.
8.2. Informative References
[RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis",
RFC 4272, DOI 10.17487/RFC4272, January 2006,
<https://www.rfc-editor.org/info/rfc4272>.
[RFC5424] Gerhards, R., "The Syslog Protocol", RFC 5424,
DOI 10.17487/RFC5424, March 2009,
<https://www.rfc-editor.org/info/rfc5424>.
[RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J.,
Morris, J., Hansen, M., and R. Smith, "Privacy
Considerations for Internet Protocols", RFC 6973,
DOI 10.17487/RFC6973, July 2013,
<https://www.rfc-editor.org/info/rfc6973>.
[UTR36] Davis, M. and M. Suignard, "Unicode Security
Considerations", Unicode Technical Report #36, August
2010, <http://unicode.org/reports/tr36/>.
Appendix A. Acknowledgements
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 BCP 78 rights to the
IETF Trust.
The authors would like to acknowledge Misha Grishin (MSK-IX) for
raising awareness that [RFC8203]'s length specification was
insufficient in context of multibyte character sets.
Appendix B. Changes to RFC 8203
Feedback from operators based in regions which predominantly use
multibyte character sets, showed that messages similar in meaning to
what can be send in other languages in using single-byte encoding,
failed to fit within the Length constraints as specified by
[RFC8203]. For example, the phrase: 'Planned work to add switch to
stack. Completion time - 30 minutes' has length 65 bytes. Its
Snijders, et al. Expires November 1, 2018 [Page 6]
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translation in Russian
'Плановые
работы по д

86;бавлению к&#
1086;ммутатора&
#1074;
стек.Время 

79;авершения -
30минут' (See PDF for non-ASCII
character string) has length 139 bytes.
Authors' Addresses
Job Snijders
NTT Communications
Theodorus Majofskistraat 100
Amsterdam 1065 SZ
The Netherlands
Email: [email protected]
Jakob Heitz
Cisco
170 West Tasman Drive
San Jose, CA 95134
United States of America
Email: [email protected]
John Scudder
Juniper Networks
1194 N. Mathilda Ave
Sunnyvale, CA 94089
United States of America
Email: [email protected]
Alexander Azimov
Qrator Labs
Email: [email protected]
Snijders, et al. Expires November 1, 2018 [Page 7]