draft-ietf-idr-bgp-gr-notification-16.txt   rfc8538.txt 
Internet Engineering Task Force K. Patel Internet Engineering Task Force (IETF) K. Patel
Internet-Draft Arrcus Request for Comments: 8538 Arrcus
Updates: 4724 (if approved) R. Fernando Updates: 4724 R. Fernando
Intended status: Standards Track Cisco Systems Category: Standards Track Cisco Systems
Expires: May 31, 2019 J. Scudder ISSN: 2070-1721 J. Scudder
J. Haas J. Haas
Juniper Networks Juniper Networks
November 27, 2018 March 2019
Notification Message support for BGP Graceful Restart Notification Message Support for BGP Graceful Restart
draft-ietf-idr-bgp-gr-notification-16.txt
Abstract Abstract
The BGP Graceful Restart mechanism defined in RFC 4724 limits the The BGP Graceful Restart mechanism defined in RFC 4724 limits the
usage of BGP Graceful Restart to BGP protocol messages other than a usage of BGP Graceful Restart to BGP messages other than BGP
BGP NOTIFICATION message. This document updates RFC 4724 by defining NOTIFICATION messages. This document updates RFC 4724 by defining an
an extension that permits the Graceful Restart procedures to be extension that permits the Graceful Restart procedures to be
performed when the BGP speaker receives a BGP NOTIFICATION Message or performed when the BGP speaker receives a BGP NOTIFICATION message or
the Hold Time expires. This document also defines a new BGP the Hold Time expires. This document also defines a new subcode for
NOTIFICATION Cease Error subcode whose effect is to request a full BGP Cease NOTIFICATION messages; this new subcode requests a full
session restart instead of a Graceful Restart. session restart instead of a Graceful Restart.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
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 This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on May 31, 2019. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8538.
Copyright Notice Copyright Notice
Copyright (c) 2018 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
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to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Modifications to BGP Graceful Restart Capability . . . . . . 3 2. Modifications to BGP Graceful Restart Capability . . . . . . 3
3. BGP Hard Reset Subcode . . . . . . . . . . . . . . . . . . . 3 3. BGP Hard Reset Subcode . . . . . . . . . . . . . . . . . . . 4
3.1. Sending a Hard Reset . . . . . . . . . . . . . . . . . . 4 3.1. Sending a Hard Reset . . . . . . . . . . . . . . . . . . 4
3.2. Receiving a Hard Reset . . . . . . . . . . . . . . . . . 4 3.2. Receiving a Hard Reset . . . . . . . . . . . . . . . . . 4
4. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Rules for the Receiving Speaker . . . . . . . . . . . . . 5 4.1. Rules for the Receiving Speaker . . . . . . . . . . . . . 6
5. Use of Hard Reset . . . . . . . . . . . . . . . . . . . . . . 6 5. Use of Hard Reset . . . . . . . . . . . . . . . . . . . . . . 7
5.1. When to Send Hard Reset . . . . . . . . . . . . . . . . . 6 5.1. When to Send a Hard Reset . . . . . . . . . . . . . . . . 7
5.2. Interaction With Other Specifications . . . . . . . . . . 7 5.2. Interaction with Other Specifications . . . . . . . . . . 7
6. Management Considerations . . . . . . . . . . . . . . . . . . 7 6. Management Considerations . . . . . . . . . . . . . . . . . . 8
7. Operational Considerations . . . . . . . . . . . . . . . . . 7 7. Operational Considerations . . . . . . . . . . . . . . . . . 8
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 9. Security Considerations . . . . . . . . . . . . . . . . . . . 9
10. Security Considerations . . . . . . . . . . . . . . . . . . . 8 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
11. Normative References . . . . . . . . . . . . . . . . . . . . 8 10.1. Normative References . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 10.2. Informative References . . . . . . . . . . . . . . . . . 9
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction 1. Introduction
For many classes of errors, the BGP protocol must send a NOTIFICATION For many classes of errors, BGP must send a NOTIFICATION message and
message and reset the peering session to handle the error condition. reset the peering session to handle the error condition. The BGP
The BGP Graceful Restart extension defined in [RFC4724] requires that Graceful Restart mechanism defined in [RFC4724] requires that normal
normal BGP procedures defined in [RFC4271] be followed when a BGP procedures defined in [RFC4271] be followed when a NOTIFICATION
NOTIFICATION message is sent or received. This document defines an message is sent or received. This document defines an extension to
extension to BGP Graceful Restart that permits the Graceful Restart BGP Graceful Restart that permits the Graceful Restart procedures to
procedures to be performed when the BGP speaker receives a be performed when the BGP speaker receives a NOTIFICATION message or
NOTIFICATION message or the Hold Time expires. This permits the BGP the Hold Time expires. This permits the BGP speaker to avoid
speaker to avoid flapping reachability and continue forwarding while flapping reachability and continue forwarding while the BGP speaker
the BGP speaker restarts the session to handle errors detected in the restarts the session to handle errors detected in BGP.
BGP protocol.
At a high level, this document can be summed up as follows. When a At a high level, this document can be summed up as follows. When a
BGP session is reset, both speakers operate as "Receiving Speakers" BGP session is reset, both speakers operate as "Receiving Speakers"
according to [RFC4724], meaning they retain each other's routes. according to [RFC4724], meaning they retain each other's routes.
This is also true for HOLDTIME expiration. The functionality can be This is also true for HOLDTIME expiration. The functionality can be
defeated using a "Hard Reset" subcode for the BGP NOTIFICATION Cease defeated by sending a BGP Cease NOTIFICATION message with the Hard
Error code. If a Hard Reset is used, a full session reset is Reset subcode. If a Hard Reset is used, a full session reset is
performed. performed.
1.1. Requirements Language 1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in
14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
2. Modifications to BGP Graceful Restart Capability 2. Modifications to BGP Graceful Restart Capability
The BGP Graceful Restart Capability is augmented to signal the The BGP Graceful Restart Capability is augmented to signal the
Graceful Restart support for BGP NOTIFICATION messages. The Restart Graceful Restart support for BGP NOTIFICATION messages. The Restart
Flags field is augmented as follows (following the diagram from Flags field is augmented as follows (following the diagram in
section 3 of [RFC4724]): Section 3 of [RFC4724]).
Restart Flags: Restart Flags:
This field contains bit flags relating to restart. This field contains bit flags relating to restart.
0 1 2 3 0 1 2 3
+-+-+-+-+ +-+-+-+-+
|R|N| | |R|N| |
+-+-+-+-+ +-+-+-+-+
The most significant ("Restart State", or "R") bit is defined in The most significant bit is defined in [RFC4724] as the Restart State
[RFC4724]. ("R") bit.
The second most significant bit ("N") is defined as the BGP Graceful The second most significant bit is defined in this document as the
Notification bit, which is used to indicate Graceful Restart support Graceful Notification ("N") bit. It is used to indicate Graceful
for BGP NOTIFICATION messages. A BGP speaker indicates support for Restart support for BGP NOTIFICATION messages. A BGP speaker
the procedures of this document, by advertising a Graceful Restart indicates support for the procedures in this document by advertising
Capability with its Graceful Notification bit set (value 1). a Graceful Restart Capability with its "N" bit set (value 1).
If a BGP speaker that previously advertised a given set of Graceful If a BGP speaker that previously advertised a given set of Graceful
Restart parameters opens a new session with a different set of Restart parameters opens a new session with a different set of
parameters, these new parameters apply once the session has parameters, these new parameters apply once the session has
transitioned into ESTABLISHED state. transitioned into ESTABLISHED state.
3. BGP Hard Reset Subcode 3. BGP Hard Reset Subcode
We define a new BGP NOTIFICATION Cease message subcode, called the This document defines a new subcode for BGP Cease NOTIFICATION
BGP Hard Reset Subcode. The value of this subcode is discussed in messages, called the Hard Reset subcode. The value of this subcode
Section 9. We refer to a BGP NOTIFICATION Cease message with the is discussed in Section 8. In this document, a BGP Cease
Hard Reset subcode as a Hard Reset message, or just a Hard Reset. NOTIFICATION message with the Hard Reset subcode is referred to as a
"Hard Reset message" or simply as a "Hard Reset".
When the "N" bit has been exchanged by two peers, to distinguish them When the "N" bit has been exchanged by two peers, NOTIFICATION
from Hard Reset we refer to any NOTIFICATION messages other than Hard messages other than Hard Reset messages are referred to as
Reset as "Graceful", since such messages invoke Graceful Restart "Graceful", since such messages invoke Graceful Restart semantics.
semantics.
3.1. Sending a Hard Reset 3.1. Sending a Hard Reset
A Hard Reset message is used to indicate to a peer with which the When the "N" bit has been exchanged, a Hard Reset message is used to
Graceful Notification bit has been exchanged, that the session is to indicate to the peer that the session is to be fully terminated.
be fully terminated.
When sending a Hard Reset, the data portion of the NOTIFICATION is When sending a Hard Reset, the data portion of the NOTIFICATION
encoded as follows: message is encoded as follows:
+--------+--------+-------- +--------+--------+--------
| ErrCode| Subcode| Data | ErrCode| Subcode| Data
+--------+--------+-------- +--------+--------+--------
ErrCode is a BGP Error Code (as documented in the IANA BGP Error ErrCode is a BGP Error Code (as documented in the IANA "BGP Error
Codes registry) that indicates the reason for the Hard Reset. (Notification) Codes" registry) that indicates the reason for the
Subcode is a BGP Error Subcode (as documented in the IANA BGP Error Hard Reset. Subcode is a BGP Error Subcode (as documented in the
Subcodes registry) as appropriate for the ErrCode. Similarly, Data IANA "BGP Error Subcodes" registry) as appropriate for the ErrCode.
is as appropriate for the ErrCode and Subcode. In short, the Hard Similarly, Data is as appropriate for the ErrCode and Subcode. In
Reset encapsulates another NOTIFICATION message in its data portion. short, the Hard Reset encapsulates another NOTIFICATION message in
its data portion.
3.2. Receiving a Hard Reset 3.2. Receiving a Hard Reset
Whenever a BGP speaker receives a Hard Reset, the speaker MUST Whenever a BGP speaker receives a Hard Reset, the speaker MUST
terminate the BGP session following the standard procedures in terminate the BGP session following the standard procedures in
[RFC4271]. [RFC4271].
4. Operation 4. Operation
A BGP speaker that is willing to receive and send BGP NOTIFICATION A BGP speaker that is willing to receive and send BGP NOTIFICATION
messages according to the procedures of this document MUST advertise messages according to the procedures of this document MUST advertise
the BGP Graceful Notification "N" bit using the Graceful Restart the "N" bit using the Graceful Restart Capability as defined in
Capability as defined in [RFC4724]. [RFC4724].
When such a BGP speaker has received the "N" bit from its peer, and When such a BGP speaker has received the "N" bit from its peer, and
receives from that peer a BGP NOTIFICATION message other than a Hard receives from that peer a BGP NOTIFICATION message other than a Hard
Reset, it MUST follow the rules for the Receiving Speaker mentioned Reset, it MUST follow the rules for the Receiving Speaker mentioned
in Section 4.1. The BGP speaker generating the BGP NOTIFICATION in Section 4.1. The BGP speaker generating the BGP NOTIFICATION
message MUST also follow the rules for the Receiving Speaker. message MUST also follow the rules for the Receiving Speaker.
When a BGP speaker resets its session due to a HOLDTIME expiry, it When a BGP speaker resets its session due to a HOLDTIME expiry, it
should generate the relevant BGP NOTIFICATION message as mentioned in should generate the relevant BGP NOTIFICATION message as mentioned in
[RFC4271], but subsequently it MUST follow the rules for the [RFC4271] but subsequently MUST follow the rules for the Receiving
Receiving Speaker mentioned in Section 4.1. Speaker mentioned in Section 4.1.
A BGP speaker SHOULD NOT send a Hard Reset to a peer from which it A BGP speaker SHOULD NOT send a Hard Reset to a peer from which it
has not received the "N" bit. We note, however, that if it did so has not received the "N" bit. We note, however, that if it did so,
the effect would be as desired in any case, since according to the effect would be as desired in any case because, according to
[RFC4271] and [RFC4724] any NOTIFICATION message, whether recognized [RFC4271] and [RFC4724], any NOTIFICATION message, whether recognized
or not, results in a session reset. Thus the only negative effect to or not, results in a session reset. Thus, the only negative effect
be expected from sending the Hard Reset to a peer that hasn't to be expected from sending the Hard Reset to a peer that hasn't
advertised compliance to this specification would be that the peer advertised compliance to this specification would be that the peer
would be unable to properly log the associated information. would be unable to properly log the associated information.
Once the session is re-established, both BGP speakers SHOULD set Once the session is re-established, both BGP speakers SHOULD set
their "Forwarding State" bit to 1. If the "Forwarding State" bit is their Forwarding State bit to 1. If the Forwarding State bit is not
not set, then according to the procedures of [RFC4724] section 4.2, set, then, according to the procedures in Section 4.2 of [RFC4724],
the relevant routes will be flushed, defeating the goals of this the relevant routes will be flushed, defeating the goals of this
specification. specification.
4.1. Rules for the Receiving Speaker 4.1. Rules for the Receiving Speaker
[RFC4724] section 4.2 defines rules for the Receiving Speaker. These Section 4.2 of [RFC4724] defines rules for the Receiving Speaker.
are modified as follows. This document modifies those rules as follows:
The sentence "To deal with possible consecutive restarts, a route The sentence "To deal with possible consecutive restarts, a route
(from the peer) previously marked as stale MUST be deleted" only (from the peer) previously marked as stale MUST be deleted" only
applies when the "N" bit has not been exchanged with the peer: applies when the "N" bit has not been exchanged with the peer:
OLD: When the Receiving Speaker detects termination of the TCP OLD: When the Receiving Speaker detects termination of the TCP
session for a BGP session with a peer that has advertised the session for a BGP session with a peer that has advertised the
Graceful Restart Capability, it MUST retain the routes received Graceful Restart Capability, it MUST retain the routes received
from the peer for all the address families that were previously from the peer for all the address families that were previously
received in the Graceful Restart Capability and MUST mark them received in the Graceful Restart Capability and MUST mark them
skipping to change at page 6, line 19 skipping to change at page 7, line 7
NEW: To put an upper bound on the amount of time a router retains the NEW: To put an upper bound on the amount of time a router retains the
stale routes, an implementation MUST support a (configurable) stale routes, an implementation MUST support a (configurable)
timer, called the "stale timer", that imposes this upper bound. timer, called the "stale timer", that imposes this upper bound.
A suggested default value for the stale timer is 180 seconds. A suggested default value for the stale timer is 180 seconds.
An implementation MAY provide the option to disable the timer An implementation MAY provide the option to disable the timer
(i.e., to provide an infinite retention time) but MUST NOT do so (i.e., to provide an infinite retention time) but MUST NOT do so
by default. by default.
5. Use of Hard Reset 5. Use of Hard Reset
5.1. When to Send Hard Reset 5.1. When to Send a Hard Reset
Although when to send a Hard Reset is an implementation-specific Although when to send a Hard Reset is an implementation-specific
decision, we offer some advice. Many Cease notification subcodes decision, we offer some advice. Many Cease NOTIFICATION subcodes
represent permanent or long-term rather than transient session represent permanent or long-term, rather than transient, session
termination, and as such it's appropriate to use Hard Reset with termination. Because of this, it's appropriate to use Hard Reset
them. At time of publication, Cease subcodes 1-9 were defined. with them. As of publication of this document, subcodes 1-9 have
been defined for Cease. The following table lists each of these
subcodes along with suggested behavior.
+-------+------------------------------------+----------------------+ +-------+------------------------------------+----------------------+
| Value | Name | Suggested Behavior | | Value | Name | Suggested Behavior |
+-------+------------------------------------+----------------------+ +-------+------------------------------------+----------------------+
| 1 | Maximum Number of Prefixes Reached | Hard Reset | | 1 | Maximum Number of Prefixes Reached | Hard Reset |
| 2 | Administrative Shutdown | Hard Reset | | 2 | Administrative Shutdown | Hard Reset |
| 3 | Peer De-configured | Hard Reset | | 3 | Peer De-configured | Hard Reset |
| 4 | Administrative Reset | Provide user control | | 4 | Administrative Reset | Provide user control |
| 5 | Connection Rejected | Graceful Cease | | 5 | Connection Rejected | Graceful Cease |
| 6 | Other Configuration Change | Graceful Cease | | 6 | Other Configuration Change | Graceful Cease |
| 7 | Connection Collision Resolution | Graceful Cease | | 7 | Connection Collision Resolution | Graceful Cease |
| 8 | Out of Resources | Graceful Cease | | 8 | Out of Resources | Graceful Cease |
| 9 | Hard Reset | Hard Reset | | 9 | Hard Reset | Hard Reset |
+-------+------------------------------------+----------------------+ +-------+------------------------------------+----------------------+
Suggestions for Cease Subcode Behavior These suggestions are only that -- suggestions, not requirements.
It's the nature of BGP implementations that the mapping of internal
These suggestions are only that, suggestions, not requirements. It's states to BGP NOTIFICATION codes and subcodes is not always perfect.
the nature of BGP implementations that the mapping of internal states The guiding principle for the implementor should be that if there is
to BGP NOTIFICATION codes and subcodes is not always perfect. The no realistic hope that forwarding can continue or that the session
guiding principle for the implementor should be that if there is no will be re-established within the deadline, Hard Reset should be
realistic hope that forwarding can continue or that the session will used.
be re-established within the deadline, Hard Reset should be used.
For all other NOTIFICATION codes other than Cease, use of Hard Reset For all NOTIFICATION codes other than Cease, use of Hard Reset does
does not appear to be indicated. not appear to be indicated.
5.2. Interaction With Other Specifications 5.2. Interaction with Other Specifications
"BGP Administrative Shutdown Communication" [RFC8203] specifies use "BGP Administrative Shutdown Communication" [RFC8203] specifies use
of the data portion of the Administrative Shutdown or Administrative of the data portion of the Administrative Shutdown or Administrative
Reset Cease to convey a short message. When [RFC8203] is used in Reset subcodes to convey a short message. When [RFC8203] is used in
conjunction with Hard Reset, the subcode of the outermost Cease MUST conjunction with Hard Reset, the subcode of the outermost Cease MUST
be Hard Reset, with the Administrative Shutdown or Reset Cease be Hard Reset, with the Administrative Shutdown or Administrative
encapsulated within. The encapsulated administrative shutdown Reset subcodes encapsulated within. The encapsulated message MUST
message MUST subsequently be processed according to [RFC8203]. subsequently be processed according to [RFC8203].
6. Management Considerations 6. Management Considerations
When reporting a Hard Reset to network management, the error code and When reporting a Hard Reset to network management, the error code and
subcode reported MUST be Cease, Hard Reset. If the network subcode reported MUST be Cease and Hard Reset, respectively. If the
management layer in use permits it, the information carried in the network management layer in use permits it, the information carried
Data portion SHOULD be reported as well. in the Data portion SHOULD be reported as well.
7. Operational Considerations 7. Operational Considerations
Note that long (or infinite) retention time may cause operational Note that long (or infinite) retention time may cause operational
issues, and should be enabled with care. issues and should be enabled with care.
8. Acknowledgements
The authors would like to thank Jim Uttaro for the suggestion, and
Emmanuel Baccelli, Bruno Decraene, Chris Hall, Warren Kumari, Paul
Mattes, Robert Raszuk, and Alvaro Retana for their review and
comments.
9. IANA Considerations 8. IANA Considerations
IANA has temporarily assigned subcode 9, named "Hard Reset", in the IANA has assigned subcode 9 ("Hard Reset") in the "BGP Cease
"BGP Cease NOTIFICATION message subcodes" registry. Upon publication NOTIFICATION message subcodes" registry.
of this document as an RFC, IANA is requested to make this allocation
permanent.
IANA is requested to establish a registry within the "Border Gateway IANA has created a sub-registry called "BGP Graceful Restart Flags"
Protocol (BGP) Parameters" grouping, to be called "BGP Graceful under the "Border Gateway Protocol (BGP) Parameters" registry. The
Restart Flags". The Registration Procedure should be Standards registration procedure is Standards Action [RFC8126]; this document
Action, the reference this document and [RFC4724], and the initial and [RFC4724] are listed as references. The initial values are as
values as follows: follows:
+--------------+---------------+------------+---------------+ +--------------+---------------+------------+-----------+
| Bit Position | Name | Short Name | Reference | | Bit Position | Name | Short Name | Reference |
+--------------+---------------+------------+---------------+ +--------------+---------------+------------+-----------+
| 0 | Restart State | R | [RFC4724] | | 0 | Restart State | R | RFC 4724 |
| 1 | Notification | N | this document | | 1 | Notification | N | RFC 8538 |
| 2, 3 | unassigned | | this document | | 2-3 | Unassigned | | |
+--------------+---------------+------------+---------------+ +--------------+---------------+------------+-----------+
IANA is requested to establish a registry within the "Border Gateway IANA has created a sub-registry called "BGP Graceful Restart Flags
Protocol (BGP) Parameters" grouping, to be called "BGP Graceful for Address Family" under the "Border Gateway Protocol (BGP)
Restart Flags for Address Family". The Registration Procedure should Parameters" registry. The registration procedure is Standards
be Standards Action, the reference this document and [RFC4724], and Action; this document and [RFC4724] are listed as references. The
the initial values as follows: initial values are as follows:
+--------------+------------------+------------+---------------+ +--------------+------------------+------------+-----------+
| Bit Position | Name | Short Name | Reference | | Bit Position | Name | Short Name | Reference |
+--------------+------------------+------------+---------------+ +--------------+------------------+------------+-----------+
| 0 | Forwarding State | F | [RFC4724] | | 0 | Forwarding State | F | RFC 4724 |
| 1-7 | unassigned | | this document | | 1-7 | Unassigned | | |
+--------------+------------------+------------+---------------+ +--------------+------------------+------------+-----------+
10. Security Considerations 9. Security Considerations
This specification doesn't change the basic security model inherent This specification doesn't change the basic security model inherent
in [RFC4724], with the exception that the protection against repeated in [RFC4724], with the exception that the protection against repeated
resets is relaxed. To mitigate the consequent risk that an attacker resets is relaxed. To mitigate the consequent risk that an attacker
could use repeated session resets to prevent stale routes from ever could use repeated session resets to prevent stale routes from ever
being deleted, we make the stale routes timer mandatory (in practice being deleted, we make the stale timer mandatory (in practice, it is
it is already ubiquitous). To the extent [RFC4724] might be said to already ubiquitous). To the extent [RFC4724] might be said to help
help defend against denials of service by making the control plane defend against denials of service by making the control plane more
more resilient, this extension may modestly increase that resilience; resilient, this extension may modestly increase that resilience;
however, there are enough confounding and deployment-specific factors however, there are enough confounding and deployment-specific factors
that no general claims can be made. that no general claims can be made.
11. Normative References 10. References
10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271, Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006, DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>. <https://www.rfc-editor.org/info/rfc4271>.
skipping to change at page 9, line 19 skipping to change at page 9, line 46
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8203] Snijders, J., Heitz, J., and J. Scudder, "BGP [RFC8203] Snijders, J., Heitz, J., and J. Scudder, "BGP
Administrative Shutdown Communication", RFC 8203, Administrative Shutdown Communication", RFC 8203,
DOI 10.17487/RFC8203, July 2017, DOI 10.17487/RFC8203, July 2017,
<https://www.rfc-editor.org/info/rfc8203>. <https://www.rfc-editor.org/info/rfc8203>.
10.2. Informative References
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
Acknowledgements
The authors would like to thank Jim Uttaro for the suggestion. The
authors would also like to thank Emmanuel Baccelli, Bruno Decraene,
Chris Hall, Warren Kumari, Paul Mattes, Robert Raszuk, and Alvaro
Retana for their reviews and comments.
Authors' Addresses Authors' Addresses
Keyur Patel Keyur Patel
Arrcus Arrcus
Email: keyur@arrcus.com Email: keyur@arrcus.com
Rex Fernando Rex Fernando
Cisco Systems Cisco Systems
170 W. Tasman Drive 170 W. Tasman Drive
San Jose, CA 95134 San Jose, CA 95134
USA United States of America
Email: rex@cisco.com Email: rex@cisco.com
John Scudder John Scudder
Juniper Networks Juniper Networks
1194 N. Mathilda Ave 1194 N. Mathilda Ave
Sunnyvale, CA 94089 Sunnyvale, CA 94089
USA United States of America
Email: jgs@juniper.net Email: jgs@juniper.net
Jeff Haas Jeff Haas
Juniper Networks Juniper Networks
1194 N. Mathilda Ave 1194 N. Mathilda Ave
Sunnyvale, CA 94089 Sunnyvale, CA 94089
USA United States of America
Email: jhaas@juniper.net Email: jhaas@juniper.net
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