draft-ietf-idr-rfc8203bis-04.txt   draft-ietf-idr-rfc8203bis-05.txt 
IDR J. Snijders IDR J. Snijders
Internet-Draft NTT Internet-Draft NTT
Obsoletes: 8203 (if approved) J. Heitz Obsoletes: 8203 (if approved) J. Heitz
Updates: 4486 (if approved) Cisco Updates: 4486 (if approved) Cisco
Intended status: Standards Track J. Scudder Intended status: Standards Track J. Scudder
Expires: October 31, 2019 Juniper Expires: April 18, 2020 Juniper
A. Azimov A. Azimov
Yandex Yandex
April 29, 2019 October 16, 2019
Extended BGP Administrative Shutdown Communication Extended BGP Administrative Shutdown Communication
draft-ietf-idr-rfc8203bis-04 draft-ietf-idr-rfc8203bis-05
Abstract Abstract
This document enhances the BGP Cease NOTIFICATION message This document enhances the BGP Cease NOTIFICATION message
"Administrative Shutdown" and "Administrative Reset" subcodes for "Administrative Shutdown" and "Administrative Reset" subcodes for
operators to transmit a short freeform message to describe why a BGP operators to transmit a short freeform message to describe why a BGP
session was shutdown or reset. This document updates RFC 4486 and session was shutdown or reset. This document updates RFC 4486 and
obsoletes RFC 8203 by defining an Extended BGP Administrative obsoletes RFC 8203 by defining an Extended BGP Administrative
Shutdown Communication to improve communication using multibyte Shutdown Communication to improve communication using multibyte
character sets. character sets.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on October 31, 2019. This Internet-Draft will expire on April 18, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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2. Shutdown Communication . . . . . . . . . . . . . . . . . . . 2 2. Shutdown Communication . . . . . . . . . . . . . . . . . . . 2
3. Operational Considerations . . . . . . . . . . . . . . . . . 3 3. Operational Considerations . . . . . . . . . . . . . . . . . 3
4. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 4 4. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 4 6. Security Considerations . . . . . . . . . . . . . . . . . . . 4
7. Implementation status - RFC EDITOR: REMOVE BEFORE PUBLICATION 5 7. Implementation status - RFC EDITOR: REMOVE BEFORE PUBLICATION 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . 5 8.1. Normative References . . . . . . . . . . . . . . . . . . 5
8.2. Informative References . . . . . . . . . . . . . . . . . 6 8.2. Informative References . . . . . . . . . . . . . . . . . 6
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 6 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 6
Appendix B. Changes to RFC 8203 . . . . . . . . . . . . . . . . 6 Appendix B. Changes to RFC 8203 . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction 1. Introduction
It can be troublesome for an operator to correlate a BGP-4 [RFC4271] It can be troublesome for an operator to correlate a BGP-4 [RFC4271]
session teardown in the network with a notice that was transmitted session teardown in the network with a notice that was transmitted
via offline methods such email or telephone calls. This document via offline methods such email or telephone calls. This document
updates [RFC4486] by specifying a mechanism to transmit a short updates [RFC4486] by specifying a mechanism to transmit a short
freeform UTF-8 [RFC3629] message as part of a Cease NOTIFICATION freeform UTF-8 [RFC3629] message as part of a Cease NOTIFICATION
message [RFC4271] to inform the peer why the BGP session is being message [RFC4271] to inform the peer why the BGP session is being
shutdown or reset. shutdown or reset. This document obsoletes [RFC8203]; the specific
differences and rationale are discussed in detail in Appendix B.
2. Shutdown Communication 2. Shutdown Communication
If a BGP speaker decides to terminate its session with a BGP If a BGP speaker decides to terminate its session with a BGP
neighbor, and it sends a NOTIFICATION message with the Error Code neighbor, and it sends a NOTIFICATION message with the Error Code
"Cease" and Error Subcode "Administrative Shutdown" or "Cease" and Error Subcode "Administrative Shutdown" or
"Administrative Reset" [RFC4486], it MAY include an UTF-8 encoded "Administrative Reset" [RFC4486], it MAY include a UTF-8 encoded
string. The contents of the string are at the operator's discretion. string. The contents of the string are at the operator's discretion.
The Cease NOTIFICATION message with a Shutdown Communication is The Cease NOTIFICATION message with a Shutdown Communication is
encoded as below: encoded as below:
0 1 2 3 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 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 | ... \ | Error code 6 | Subcode | Length | ... \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /
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Length: this 8-bit field represents the length of the Shutdown Length: this 8-bit field represents the length of the Shutdown
Communication field in octets. When the length value is zero, no Communication field in octets. When the length value is zero, no
Shutdown Communication field follows. Shutdown Communication field follows.
Shutdown Communication: to support international characters, the Shutdown Communication: to support international characters, the
Shutdown Communication field MUST be encoded using UTF-8. A Shutdown Communication field MUST be encoded using UTF-8. A
receiving BGP speaker MUST NOT interpret invalid UTF-8 sequences. receiving BGP speaker MUST NOT interpret invalid UTF-8 sequences.
Note that when the Shutdown Communication contains multibyte Note that when the Shutdown Communication contains multibyte
characters, the number of characters will be less than the length characters, the number of characters will be less than the length
value. This field is not NUL terminated. value. This field is not NULL terminated.
Mechanisms concerning the reporting of information contained in the Mechanisms concerning the reporting of information contained in the
Shutdown Communication are implementation specific but SHOULD include Shutdown Communication are implementation specific but SHOULD include
methods such as Syslog [RFC5424]. methods such as Syslog [RFC5424].
3. Operational Considerations 3. Operational Considerations
Operators are encouraged to use the Shutdown Communication to inform Operators are encouraged to use the Shutdown Communication to inform
their peers of the reason for the shutdown of the BGP session and their peers of the reason for the shutdown of the BGP session and
include out-of-band reference materials. An example of a useful include out-of-band reference materials. An example of a useful
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"[TICKET-1-1438367390] software upgrade; back in 2 hours" "[TICKET-1-1438367390] software upgrade; back in 2 hours"
"[TICKET-1-1438367390]" is a ticket reference with significance to "[TICKET-1-1438367390]" is a ticket reference with significance to
both the sender and receiver, followed by a brief human-readable both the sender and receiver, followed by a brief human-readable
message regarding the reason for the BGP session shutdown followed by message regarding the reason for the BGP session shutdown followed by
an indication about the length of the maintenance. The receiver can an indication about the length of the maintenance. The receiver can
now use the string 'TICKET-1-1438367390' to search in their email now use the string 'TICKET-1-1438367390' to search in their email
archive to find more details. archive to find more details.
If a Shutdown Communication longer than 128 octets is sent to a BGP
speaker that implements [RFC8203], then that speaker will treat it as
an error, the consequence of which is a log message. For this
reason, operators would be wise to keep shutdown communications to
less than 128 octets when feasible.
There is no guarantee that the receiver supports either this
specification or [RFC8203], so any shutdown communication might not
be logged in an easily-readable form at all. Therefore, operators
would also be wise not to rely on shutdown communications as their
sole form of communication with their peer for important events.
4. Error Handling 4. Error Handling
If a Shutdown Communication with an invalid Length value, or an If a Shutdown Communication with an invalid UTF-8 sequence is
invalid UTF-8 sequence is received, a message indicating this event received, a message indicating this event SHOULD be logged for the
SHOULD be logged for the attention of the operator. An erroneous or attention of the operator. An erroneous or malformed Shutdown
malformed Shutdown Communication itself MAY be logged in a hexdump Communication itself MAY be logged in a hexdump format.
format.
5. IANA Considerations 5. IANA Considerations
Per this document, IANA is requested to reference this document at Per this document, IANA is requested to reference this document at
subcode "Administrative Shutdown", and at subcode "Administrative subcode "Administrative Shutdown", and at subcode "Administrative
Reset" in the "Cease NOTIFICATION message subcodes" registry under Reset" in the "Cease NOTIFICATION message subcodes" registry under
the "Border Gateway Protocol (BGP) Parameters" group in addition to the "Border Gateway Protocol (BGP) Parameters" group in addition to
[RFC4486] and [RFC8203]. [RFC4486] and [RFC8203].
6. Security Considerations 6. Security Considerations
This document uses UTF-8 encoding for the Shutdown Communication. This document uses UTF-8 encoding for the Shutdown Communication.
There are a number of security issues with Unicode. Implementers and There are a number of security issues with Unicode. Implementers and
operators are advised to review Unicode Technical Report #36 [UTR36] operators are advised to review Unicode Technical Report #36 [UTR36]
to learn about these issues. UTF-8 "Shortest Form" encoding is to learn about these issues. UTF-8 "Shortest Form" encoding is
REQUIRED to guard against the technical issues outlined in [UTR36]. REQUIRED to guard against the technical issues outlined in [UTR36].
As BGP Shutdown Communications are likely to appear in syslog output, As BGP Shutdown Communications are likely to appear in syslog output,
there is a risk that carefully constructed Shutdown Communication there is a risk that carefully constructed Shutdown Communication
might be formatted by receiving systems in a way to make them appear 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 as additional syslog messages. The 255 octet length limit on the BGP
attack, the BGP Shutdown Communication is limited to 255 octets in Shutdown Communication may help limit the ability to mount such an
length. attack.
Users of this mechanism should be aware that unless a transport that Users of this mechanism should be aware that unless a transport that
provides integrity is used for the BGP session in question, a provides integrity is used for the BGP session in question, a
Shutdown Communication message could be forged. Unless a transport Shutdown Communication message could be forged. Unless a transport
that provides confidentiality is used, a Shutdown Communication that provides confidentiality is used, a Shutdown Communication
message could be snooped by an attacker. These issues are common to 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 any BGP message but may be of greater interest in the context of this
proposal since the information carried in the message is generally proposal since the information carried in the message is generally
expected to be used for human-to-human communication. Refer to the expected to be used for human-to-human communication. Refer to the
related considerations in [RFC4271] and [RFC4272]. related considerations in [RFC4271] and [RFC4272].
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The authors would like to thank Enke Chen and Vincent Gillet for 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 their work on [RFC4486] and granting the related BCP 78 rights to the
IETF Trust. IETF Trust.
The authors would like to acknowledge Misha Grishin (MSK-IX) for The authors would like to acknowledge Misha Grishin (MSK-IX) for
raising awareness that [RFC8203]'s length specification was raising awareness that [RFC8203]'s length specification was
insufficient in context of multibyte character sets. insufficient in context of multibyte character sets.
Appendix B. Changes to RFC 8203 Appendix B. Changes to RFC 8203
The maximum permitted length was changed from 128 to 255.
Feedback from operators based in regions which predominantly use Feedback from operators based in regions which predominantly use
multibyte character sets, showed that messages similar in meaning to multibyte character sets, showed that messages similar in meaning to
what can be send in other languages in using single-byte encoding, what can be send in other languages in using single-byte encoding,
failed to fit within the Length constraints as specified by failed to fit within the Length constraints as specified by
[RFC8203]. For example, the phrase: 'Planned work to add switch to [RFC8203]. For example, the phrase: 'Planned work to add switch to
stack. Completion time - 30 minutes' has length 65 bytes. Its stack. Completion time - 30 minutes' has length 65 bytes. Its
translation in Russian translation in Russian
'Плановые 'Плановые
работы по д&#10 работы по д&#10
86;бавлению к&# 86;бавлению к&#
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