Network Working Group P. Mohapatra
Internet-Draft K. Patel
Intended status: Standards Track Cisco Systems
Expires: October 28, 2010 J. Scudder
D. Ward
Juniper Networks
R. Bush
Internet Initiative Japan, Inc.
April 26, 2010
BGP Prefix Origin Validation State Extended Community
draft-pmohapat-sidr-origin-validation-signaling-00
Abstract
As part of the origination AS validation process, it can be desirable
to automatically consider the validation state of routes in the BGP
decision process. The purpose of this document is to provide a
specification for doing so. The document also defines a new BGP
opaque extended community to carry the validation state inside an
autonomous system to influence the decision process of the IBGP
speakers.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
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This Internet-Draft will expire on October 28, 2010.
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Requirements Language . . . . . . . . . . . . . . . . . . . 4
2. Origin Validation State Extended Community . . . . . . . . . . 4
3. Changes to the BGP Decision Process . . . . . . . . . . . . . . 5
3.1. Policy Control . . . . . . . . . . . . . . . . . . . . . . 5
4. Deployment Considerations . . . . . . . . . . . . . . . . . . . 5
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
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1. Introduction
As part of the origination AS validation process, it can be desirable
to automatically consider the validation state of routes in the BGP
decision process. The purpose of this document is to provide a
specification for doing so. The document defines a new BGP opaque
extended community to carry the validation state inside an autonomous
system to influence the decision process of the IBGP speakers.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. Origin Validation State Extended Community
The origin validation state extended community is an opaque extended
community [RFC4360] with the following encoding:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x43 | TBD | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |validationstate|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The value of the high-order octet of the extended Type Field is 0x43,
which indicates it is non-transitive. The value of the low-order
octet of the extended type field for this community is TBD. The last
octet of the extended community encodes the route's validation
state([I-D.pmohapat-sidr-pfx-validate]. It can assume the following
values:
+-------+-----------------------------+
| Value | Meaning |
+-------+-----------------------------+
| 0 | Lookup result = "valid" |
| 1 | Lookup result = "not found" |
| 2 | Lookup result = "invalid" |
+-------+-----------------------------+
If the router is configured to support the extensions defined in this
draft, it SHOULD attach the origin validation state extended
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community to BGP UPDATE messages sent to IBGP peers by mapping the
computed validation state in the last octet of the extended
community. Similarly on the receiving IBGP speakers, the validation
state of an IBGP route SHOULD be derived directly from the last octet
of the extended community, if present. Note that routers do not
perform prefix origin validation (compute the validation state as
defined in [I-D.pmohapat-sidr-pfx-validate]) for IBGP learnt routes.
Since the extended community is defined to be non-transitive, it MUST
not be attached while advertising routes to EBGP peers.
Additionally, if it is present in an UPDATE message received from an
EBGP peer, the router MUST remove the origin validation state
extended community before parsing rest of the message.
3. Changes to the BGP Decision Process
If a BGP router supports prefix origin validation and is configured
for the extensions defined in this document, the validation step MUST
be performed prior to any of the steps defined in the decision
process of [RFC4271]. The validation step is stated as follows:
When comparing a pair of routes for a BGP destination, the route
with the lowest "validation state" value is preferred.
In all other respects, the decision process remains unchanged.
3.1. Policy Control
It MUST be possible to enable or disable the validation step as
defined in Section 3 through configuration. The default SHOULD be
for the validation step to be disabled.
4. Deployment Considerations
In deployment scenarios where not all the speakers in an autonomous
system are upgraded to support the extensions defined in this
document, it is necessary to define policies that match on the origin
validation extended community and set another BGP attribute
[I-D.pmohapat-sidr-pfx-validate] that influences the best path
selection the same way as what would have been enabled by an
implementation of this extension.
5. Acknowledgements
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6. IANA Considerations
IANA shall assign a new value from the "BGP Opaque Extended
Community" type registry from the non-transitive range, to be called
"BGP Origin Validation State Extended Community".
7. Security Considerations
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006.
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
Communities Attribute", RFC 4360, February 2006.
8.2. Informative References
[I-D.pmohapat-sidr-pfx-validate]
Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R.
Austein, "BGP Prefix Origin Validation",
draft-pmohapat-sidr-pfx-validate-06 (work in progress),
April 2010.
Authors' Addresses
Pradosh Mohapatra
Cisco Systems
170 W. Tasman Drive
San Jose, CA 95134
USA
Email: pmohapat@cisco.com
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Keyur Patel
Cisco Systems
170 W. Tasman Drive
San Jose, CA 95134
USA
Email: keyupate@cisco.com
John Scudder
Juniper Networks
1194 N. Mathilda Ave
Sunnyvale, CA 94089
USA
Email: jgs@juniper.net
David Ward
Juniper Networks
1194 N. Mathilda Ave
Sunnyvale, CA 94089
USA
Email: dward@juniper.net
Randy Bush
Internet Initiative Japan, Inc.
5147 Crystal Springs
Bainbridge Island, Washington 98110
USA
Email: randy@psg.com
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