draft-ietf-idr-custom-decision-02.txt   draft-ietf-idr-custom-decision-03.txt 
Inter-Domain Routing A. Retana Inter-Domain Routing A. Retana
Internet-Draft Cisco Systems, Inc. Internet-Draft Cisco Systems, Inc.
Intended status: Standards Track R. White Intended status: Standards Track R. White
Expires: May 20, 2013 Verisign Expires: November 21, 2013 Verisign
November 16, 2012 May 20, 2013
BGP Custom Decision Process BGP Custom Decision Process
draft-ietf-idr-custom-decision-02 draft-ietf-idr-custom-decision-03
Abstract Abstract
The BGP specification defines a Decision Process for installation of The BGP specification defines a Decision Process for installation of
routes into the Loc-RIB. This process takes into account an routes into the Loc-RIB. This process takes into account an
extensive series of path attributes, which can be manipulated to extensive series of path attributes, which can be manipulated to
indicate preference for specific paths. It is cumbersome (if at all indicate preference for specific paths. It is cumbersome (if at all
possible) for the end user to define policies that will select, after possible) for the end user to define policies that will select, after
partial comparison, a path based on subjective local (domain and/or partial comparison, a path based on subjective local (domain and/or
node) criteria. node) criteria.
This document defines a new Extended Community, called the Cost This document defines a new Extended Community, called the Cost
Community, which may be used in tie breaking during the best path Community, which may be used in tie breaking during the best path
selection process. The end result is a local custom decision selection process. The end result is a local custom decision
process. process.
Status of this Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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 20, 2013. This Internet-Draft will expire on November 21, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2013 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
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . . 3 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. The BGP Cost Community . . . . . . . . . . . . . . . . . . . . 4 3. The BGP Cost Community . . . . . . . . . . . . . . . . . . . 3
4. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Deployment Considerations . . . . . . . . . . . . . . . . . . . 6 5. Deployment Considerations . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
9.1. Normative References . . . . . . . . . . . . . . . . . . . 7 9.1. Normative References . . . . . . . . . . . . . . . . . . 6
9.2. Informative References . . . . . . . . . . . . . . . . . . 7 9.2. Informative References . . . . . . . . . . . . . . . . . 7
Appendix A. Cost Community Point of Insertion Registry . . . . . . 7 Appendix A. Cost Community Point of Insertion Registry . . . . . 7
Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . . 8 Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 8
B.1. Changes between the -00 and -01 versions. . . . . . . . . . 8 B.1. Changes between the -00 and -01 versions. . . . . . . . . 8
B.2. Changes between the -01 and -02 versions. . . . . . . . . . 8 B.2. Changes between the -01 and -02 versions. . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9 B.3. Changes between the -02 and -03 versions. . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction 1. Introduction
There are a number of metrics available within the BGP decision There are a number of metrics available within the BGP decision
process [RFC4271] which can be used to determine the exit point for process [RFC4271] which can be used to determine the exit point for
traffic, but there is no metric, or combination of metrics, which can traffic, but there is no metric, or combination of metrics, which can
be used to break a tie among generally equal paths. be used to break a tie among generally equal paths.
o LOCAL_PREF: The LOCAL_PREF is an absolute tie breaker near the o LOCAL_PREF: The LOCAL_PREF is an absolute tie breaker near the
beginning of the decision process. There is no way to configure beginning of the decision process. There is no way to configure
skipping to change at page 4, line 19 skipping to change at page 4, line 5
Type Field: Type Field:
The value of the high-order octet of this Opaque Extended The value of the high-order octet of this Opaque Extended
Community is 0x03 or 0x43. The value of the low-order octet of Community is 0x03 or 0x43. The value of the low-order octet of
the extended type field for this community is 0x01. the extended type field for this community is 0x01.
Value Field: Value Field:
The Value field contains three distinct sub-fields, described The Value field contains three distinct sub-fields, described
below: below:
+------------------------------+ +------------------------------+
| Point of Insertion (1 octet) | | Point of Insertion (1 octet) |
+------------------------------+ +------------------------------+
| Community-ID (1 octet) | | Community-ID (1 octet) |
+------------------------------+ +------------------------------+
| Cost (4 octets) | | Cost (4 octets) |
+------------------------------+ +------------------------------+
The Point of Insertion sub-field contains the value of the path The Point of Insertion sub-field contains the value of the path
attribute *after* which this community MUST be considered during attribute *after* which this community MUST be considered during
the best path selection process. the best path selection process.
The BGP decision process includes some steps that do not The BGP decision process includes some steps that do not
correspond to any path attribute; the following values are correspond to any path attribute; the following values are
defined: defined:
128 ABSOLUTE_VALUE - Indicates that the Cost Community MUST be 128 ABSOLUTE_VALUE - Indicates that the Cost Community MUST be
skipping to change at page 7, line 13 skipping to change at page 6, line 48
for the Opaque Extended Community type. for the Opaque Extended Community type.
9. References 9. References
9.1. Normative References 9.1. 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, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4020] Kompella, K. and A. Zinin, "Early IANA Allocation of [RFC4020] Kompella, K. and A. Zinin, "Early IANA Allocation of
Standards Track Code Points", BCP 100, RFC 4020, Standards Track Code Points", BCP 100, RFC 4020, February
February 2005. 2005.
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended [RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
Communities Attribute", RFC 4360, February 2006. Communities Attribute", RFC 4360, February 2006.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008. May 2008.
9.2. Informative References 9.2. Informative References
[BGP_EXT] Internet Assigned Numbers Authority, "BGP Extended [BGP_EXT] Internet Assigned Numbers Authority, "BGP Extended
Communities", 2010, Communities", 2010, <http://www.iana.org/assignments/bgp-
<http://www.iana.org/assignments/ extended-communities>.
bgp-extended-communities>.
[BGP_PAR] Internet Assigned Numbers Authority, "BGP Parameters", [BGP_PAR] Internet Assigned Numbers Authority, "BGP Parameters",
2010, <http://www.iana.org/assignments/bgp-parameters/>. 2010, <http://www.iana.org/assignments/bgp-parameters/>.
[RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006. Protocol 4 (BGP-4)", RFC 4271, January 2006.
[RFC4456] Bates, T., Chen, E., and R. Chandra, "BGP Route [RFC4456] Bates, T., Chen, E., and R. Chandra, "BGP Route
Reflection: An Alternative to Full Mesh Internal BGP Reflection: An Alternative to Full Mesh Internal BGP
(IBGP)", RFC 4456, April 2006. (IBGP)", RFC 4456, April 2006.
skipping to change at page 9, line 7 skipping to change at page 8, line 29
sections. sections.
B.2. Changes between the -01 and -02 versions. B.2. Changes between the -01 and -02 versions.
o Updated authors' contact information. o Updated authors' contact information.
o Added text to replace a step in the selection process. o Added text to replace a step in the selection process.
o Minor edits. o Minor edits.
B.3. Changes between the -02 and -03 versions.
o No changes; just a refresh.
Authors' Addresses Authors' Addresses
Alvaro Retana Alvaro Retana
Cisco Systems, Inc. Cisco Systems, Inc.
7025 Kit Creek Rd. 7025 Kit Creek Rd.
Research Triangle Park, NC 27709 Research Triangle Park, NC 27709
USA USA
Email: aretana@cisco.com Email: aretana@cisco.com
 End of changes. 10 change blocks. 
34 lines changed or deleted 38 lines changed or added

This html diff was produced by rfcdiff 1.41. The latest version is available from http://tools.ietf.org/tools/rfcdiff/