draft-ietf-idr-error-handling-16.txt   draft-ietf-idr-error-handling-17.txt 
Internet Engineering Task Force E. Chen, Ed. Internet Engineering Task Force E. Chen, Ed.
Internet-Draft Cisco Systems, Inc. Internet-Draft Cisco Systems, Inc.
Updates: 1997, 4271, 4360, 4456, 4760, J. Scudder, Ed. Updates: 1997, 4271, 4360, 4456, 4760, J. Scudder, Ed.
5543, 5701, 6368 (if approved) Juniper Networks 5543, 5701, 6368 (if approved) Juniper Networks
Intended status: Standards Track P. Mohapatra Intended status: Standards Track P. Mohapatra
Expires: May 16, 2015 Sproute Networks Expires: June 15, 2015 Sproute Networks
K. Patel K. Patel
Cisco Systems, Inc. Cisco Systems, Inc.
November 12, 2014 December 12, 2014
Revised Error Handling for BGP UPDATE Messages Revised Error Handling for BGP UPDATE Messages
draft-ietf-idr-error-handling-16 draft-ietf-idr-error-handling-17
Abstract Abstract
According to the base BGP specification, a BGP speaker that receives According to the base BGP specification, a BGP speaker that receives
an UPDATE message containing a malformed attribute is required to an UPDATE message containing a malformed attribute is required to
reset the session over which the offending attribute was received. reset the session over which the offending attribute was received.
This behavior is undesirable, because a session reset would impact This behavior is undesirable, because a session reset would impact
not only routes with the offending attribute, but also other, valid not only routes with the offending attribute, but also other, valid
routes exchanged over the session. This document partially revises routes exchanged over the session. This document partially revises
the error handling for UPDATE messages and provides guidelines for the error handling for UPDATE messages and provides guidelines for
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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 http://datatracker.ietf.org/drafts/current/. Drafts is at http://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 May 16, 2015. This Internet-Draft will expire on June 15, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the Copyright (c) 2014 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
(http://trustee.ietf.org/license-info) in effect on the date of (http://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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5.2. Missing NLRI . . . . . . . . . . . . . . . . . . . . . . 7 5.2. Missing NLRI . . . . . . . . . . . . . . . . . . . . . . 7
5.3. Syntactic Correctness of NLRI Fields . . . . . . . . . . 8 5.3. Syntactic Correctness of NLRI Fields . . . . . . . . . . 8
5.4. Typed NLRI . . . . . . . . . . . . . . . . . . . . . . . 8 5.4. Typed NLRI . . . . . . . . . . . . . . . . . . . . . . . 8
6. Operational Considerations . . . . . . . . . . . . . . . . . 9 6. Operational Considerations . . . . . . . . . . . . . . . . . 9
7. Error Handling Procedures for Existing Attributes . . . . . . 10 7. Error Handling Procedures for Existing Attributes . . . . . . 10
7.1. ORIGIN . . . . . . . . . . . . . . . . . . . . . . . . . 10 7.1. ORIGIN . . . . . . . . . . . . . . . . . . . . . . . . . 10
7.2. AS_PATH . . . . . . . . . . . . . . . . . . . . . . . . . 10 7.2. AS_PATH . . . . . . . . . . . . . . . . . . . . . . . . . 10
7.3. NEXT_HOP . . . . . . . . . . . . . . . . . . . . . . . . 11 7.3. NEXT_HOP . . . . . . . . . . . . . . . . . . . . . . . . 11
7.4. MULTI_EXIT_DISC . . . . . . . . . . . . . . . . . . . . . 11 7.4. MULTI_EXIT_DISC . . . . . . . . . . . . . . . . . . . . . 11
7.5. LOCAL_PREF . . . . . . . . . . . . . . . . . . . . . . . 11 7.5. LOCAL_PREF . . . . . . . . . . . . . . . . . . . . . . . 11
7.6. ATOMIC_AGGREGATE . . . . . . . . . . . . . . . . . . . . 11 7.6. ATOMIC_AGGREGATE . . . . . . . . . . . . . . . . . . . . 12
7.7. AGGREGATOR . . . . . . . . . . . . . . . . . . . . . . . 12 7.7. AGGREGATOR . . . . . . . . . . . . . . . . . . . . . . . 12
7.8. Community . . . . . . . . . . . . . . . . . . . . . . . . 12 7.8. Community . . . . . . . . . . . . . . . . . . . . . . . . 12
7.9. ORIGINATOR_ID . . . . . . . . . . . . . . . . . . . . . . 12 7.9. ORIGINATOR_ID . . . . . . . . . . . . . . . . . . . . . . 12
7.10. CLUSTER_LIST . . . . . . . . . . . . . . . . . . . . . . 12 7.10. CLUSTER_LIST . . . . . . . . . . . . . . . . . . . . . . 13
7.11. MP_REACH_NLRI . . . . . . . . . . . . . . . . . . . . . . 13 7.11. MP_REACH_NLRI . . . . . . . . . . . . . . . . . . . . . . 13
7.12. MP_UNREACH_NLRI . . . . . . . . . . . . . . . . . . . . . 13 7.12. MP_UNREACH_NLRI . . . . . . . . . . . . . . . . . . . . . 13
7.13. Traffic Engineering path attribute . . . . . . . . . . . 13 7.13. Traffic Engineering path attribute . . . . . . . . . . . 13
7.14. Extended Community . . . . . . . . . . . . . . . . . . . 13 7.14. Extended Community . . . . . . . . . . . . . . . . . . . 14
7.15. IPv6 Address Specific BGP Extended Community Attribute . 14 7.15. IPv6 Address Specific BGP Extended Community Attribute . 14
7.16. ATTR_SET . . . . . . . . . . . . . . . . . . . . . . . . 14 7.16. ATTR_SET . . . . . . . . . . . . . . . . . . . . . . . . 14
8. Guidance for Authors of BGP Specifications . . . . . . . . . 14 8. Guidance for Authors of BGP Specifications . . . . . . . . . 15
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
10. Security Considerations . . . . . . . . . . . . . . . . . . . 15 10. Security Considerations . . . . . . . . . . . . . . . . . . . 15
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 16
12.1. Normative References . . . . . . . . . . . . . . . . . . 16 12.1. Normative References . . . . . . . . . . . . . . . . . . 16
12.2. Informative References . . . . . . . . . . . . . . . . . 17 12.2. Informative References . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction 1. Introduction
According to the base BGP specification [RFC4271], a BGP speaker that According to the base BGP specification [RFC4271], a BGP speaker that
receives an UPDATE message containing a malformed attribute is receives an UPDATE message containing a malformed attribute is
required to reset the session over which the offending attribute was required to reset the session over which the offending attribute was
received. This behavior is undesirable, because a session reset received. This behavior is undesirable, because a session reset
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revised. revised.
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", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
2. Error-Handling Approaches 2. Error-Handling Approaches
In this document we refer to four different approaches to handling In this document we refer to four different approaches to handle
errors found in BGP path attributes. They are as follows (listed in errors found in BGP path attributes. They are as follows (listed in
order, from the one with the "strongest" action to the one with the order, from the one with the "strongest" action to the one with the
"weakest" action): "weakest" action):
o Session reset: This is the approach used throughout the base BGP o Session reset: This is the approach used throughout the base BGP
specification [RFC4271], where a NOTIFICATION is sent and the specification [RFC4271], where a NOTIFICATION is sent and the
session terminated. session terminated.
o AFI/SAFI disable: [RFC4760] specifies a procedure for disabling a o AFI/SAFI disable: [RFC4760] specifies a procedure for disabling a
particular AFI/SAFI. particular AFI/SAFI.
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o Treat-as-withdraw: In this approach, the UPDATE message containing o Treat-as-withdraw: In this approach, the UPDATE message containing
the path attribute in question MUST be treated as though all the path attribute in question MUST be treated as though all
contained routes had been withdrawn just as if they had been contained routes had been withdrawn just as if they had been
listed in the WITHDRAWN ROUTES field (or in the MP_UNREACH_NLRI listed in the WITHDRAWN ROUTES field (or in the MP_UNREACH_NLRI
attribute if appropriate) of the UPDATE message, thus causing them attribute if appropriate) of the UPDATE message, thus causing them
to be removed from the Adj-RIB-In according to the procedures of to be removed from the Adj-RIB-In according to the procedures of
[RFC4271]. [RFC4271].
o Attribute discard: In this approach the malformed attribute MUST o Attribute discard: In this approach the malformed attribute MUST
be discarded and the UPDATE message continues to be processed. be discarded and the UPDATE message continues to be processed.
This approach must not be used except in the case of an attribute This approach MUST NOT be used except in the case of an attribute
that has no effect on route selection or installation. that has no effect on route selection or installation.
3. Revision to BGP UPDATE Message Error Handling 3. Revision to BGP UPDATE Message Error Handling
This specification amends [RFC4271] Section 6.3 in a number of ways. This specification amends [RFC4271] Section 6.3 in a number of ways.
See also Section 7 for treatment of specific path attributes. See also Section 7 for treatment of specific path attributes.
a. The first paragraph is revised as follows: a. The first paragraph is revised as follows:
Old Text: Old Text:
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[RFC4271] also says that an implementation optionally "MAY check [RFC4271] also says that an implementation optionally "MAY check
whether the leftmost ... AS in the AS_PATH attribute is equal to the whether the leftmost ... AS in the AS_PATH attribute is equal to the
autonomous system number of the peer that sent the message". A BGP autonomous system number of the peer that sent the message". A BGP
implementation SHOULD also handle routes that violate this check implementation SHOULD also handle routes that violate this check
using "treat-as-withdraw", but MAY follow the session reset behavior using "treat-as-withdraw", but MAY follow the session reset behavior
if configured to do so. if configured to do so.
7.3. NEXT_HOP 7.3. NEXT_HOP
The attribute is considered malformed if its length is not 4 The attribute is considered malformed if its length is not 4
[RFC4271]. [RFC4271]. A length of 16 is also permissible if [RFC5549] is in use
and all conditions given in that specification have been satisfied.
An UPDATE message with a malformed NEXT_HOP attribute SHALL be An UPDATE message with a malformed NEXT_HOP attribute SHALL be
handled using the approach of "treat-as-withdraw". handled using the approach of "treat-as-withdraw".
7.4. MULTI_EXIT_DISC 7.4. MULTI_EXIT_DISC
The attribute is considered malformed if its length is not 4 The attribute is considered malformed if its length is not 4
[RFC4271]. [RFC4271].
An UPDATE message with a malformed MULTI_EXIT_DISC attribute SHALL be An UPDATE message with a malformed MULTI_EXIT_DISC attribute SHALL be
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Rekhter, "Graceful Restart Mechanism for BGP", RFC 4724, Rekhter, "Graceful Restart Mechanism for BGP", RFC 4724,
January 2007. January 2007.
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter, [RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760, January "Multiprotocol Extensions for BGP-4", RFC 4760, January
2007. 2007.
[RFC5543] Ould-Brahim, H., Fedyk, D., and Y. Rekhter, "BGP Traffic [RFC5543] Ould-Brahim, H., Fedyk, D., and Y. Rekhter, "BGP Traffic
Engineering Attribute", RFC 5543, May 2009. Engineering Attribute", RFC 5543, May 2009.
[RFC5549] Le Faucheur, F. and E. Rosen, "Advertising IPv4 Network
Layer Reachability Information with an IPv6 Next Hop", RFC
5549, May 2009.
[RFC5701] Rekhter, Y., "IPv6 Address Specific BGP Extended Community [RFC5701] Rekhter, Y., "IPv6 Address Specific BGP Extended Community
Attribute", RFC 5701, November 2009. Attribute", RFC 5701, November 2009.
[RFC6368] Marques, P., Raszuk, R., Patel, K., Kumaki, K., and T. [RFC6368] Marques, P., Raszuk, R., Patel, K., Kumaki, K., and T.
Yamagata, "Internal BGP as the Provider/Customer Edge Yamagata, "Internal BGP as the Provider/Customer Edge
Protocol for BGP/MPLS IP Virtual Private Networks (VPNs)", Protocol for BGP/MPLS IP Virtual Private Networks (VPNs)",
RFC 6368, September 2011. RFC 6368, September 2011.
[RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet [RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet
Autonomous System (AS) Number Space", RFC 6793, December Autonomous System (AS) Number Space", RFC 6793, December
2012. 2012.
12.2. Informative References 12.2. Informative References
[I-D.ietf-l2vpn-evpn] [I-D.ietf-l2vpn-evpn]
Sajassi, A., Aggarwal, R., Bitar, N., Isaac, A., and J. Sajassi, A., Aggarwal, R., Bitar, N., Isaac, A., and J.
Uttaro, "BGP MPLS Based Ethernet VPN", draft-ietf-l2vpn- Uttaro, "BGP MPLS Based Ethernet VPN", draft-ietf-l2vpn-
evpn-11 (work in progress), October 2014. evpn-11 (work in progress), October 2014.
[RFC5549] Le Faucheur, F. and E. Rosen, "Advertising IPv4 Network
Layer Reachability Information with an IPv6 Next Hop", RFC
5549, May 2009.
[RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP [RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP
Encodings and Procedures for Multicast in MPLS/BGP IP Encodings and Procedures for Multicast in MPLS/BGP IP
VPNs", RFC 6514, February 2012. VPNs", RFC 6514, February 2012.
[RFC7117] Aggarwal, R., Kamite, Y., Fang, L., Rekhter, Y., and C. [RFC7117] Aggarwal, R., Kamite, Y., Fang, L., Rekhter, Y., and C.
Kodeboniya, "Multicast in Virtual Private LAN Service Kodeboniya, "Multicast in Virtual Private LAN Service
(VPLS)", RFC 7117, February 2014. (VPLS)", RFC 7117, February 2014.
Authors' Addresses Authors' Addresses
 End of changes. 14 change blocks. 
16 lines changed or deleted 17 lines changed or added

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