draft-ietf-grow-bgp-session-culling-03.txt   draft-ietf-grow-bgp-session-culling-04.txt 
Global Routing Operations W. Hargrave Global Routing Operations W. Hargrave
Internet-Draft LONAP Internet-Draft LONAP
Intended status: Best Current Practice M. Griswold Intended status: Best Current Practice M. Griswold
Expires: February 19, 2018 20C Expires: March 14, 2018 20C
J. Snijders J. Snijders
NTT NTT
N. Hilliard N. Hilliard
INEX INEX
August 18, 2017 September 10, 2017
Mitigating Negative Impact of Maintenance through BGP Session Culling Mitigating Negative Impact of Maintenance through BGP Session Culling
draft-ietf-grow-bgp-session-culling-03 draft-ietf-grow-bgp-session-culling-04
Abstract Abstract
This document outlines an approach to mitigate negative impact on This document outlines an approach to mitigate negative impact on
networks resulting from maintenance activities. It includes guidance networks resulting from maintenance activities. It includes guidance
for both IP networks and Internet Exchange Points (IXPs). The for both IP networks and Internet Exchange Points (IXPs). The
approach is to ensure BGP-4 sessions affected by the maintenance are approach is to ensure BGP-4 sessions affected by the maintenance are
forcefully torn down before the actual maintenance activities forcefully torn down before the actual maintenance activities
commence. commence.
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 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 February 19, 2018. This Internet-Draft will expire on March 14, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 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 (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
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 . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
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3. BGP Session Culling 3. BGP Session Culling
From the viewpoint of the IP network operator, there are two types of From the viewpoint of the IP network operator, there are two types of
BGP Session Culling: BGP Session Culling:
Voluntary BGP Session Teardown: The Operator initiates the tear down Voluntary BGP Session Teardown: The Operator initiates the tear down
of the potentially affected BGP session by issuing an of the potentially affected BGP session by issuing an
Administrative Shutdown. Administrative Shutdown.
Involuntary BGP Session Teardown: The Caretaker of the lower layer Involuntary BGP Session Teardown: The Caretaker of the lower layer
network disrupts BGP control-plane traffic in the upper layer, network disrupts (higher layer) BGP control-plane traffic, causing
causing the BGP Hold Timers of the affected BGP session to expire, the BGP Hold Timers of the affected BGP session to expire,
subsequently triggering rerouting of end user traffic. subsequently triggering rerouting of end user traffic.
3.1. Voluntary BGP Session Teardown Recommendations 3.1. Voluntary BGP Session Teardown Recommendations
Before an Operator commences activities which can cause disruption to Before an Operator commences activities which can cause disruption to
the flow of data through the lower layer network, an operator can the flow of data through the lower layer network, an operator can
reduce loss of traffic by issuing an administrative shutdown to all reduce loss of traffic by issuing an administrative shutdown to all
BGP sessions running across the lower layer network and wait a few BGP sessions running across the lower layer network and wait a few
minutes for data-plane traffic to subside. minutes for data-plane traffic to subside.
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carry out the Voluntary BGP Session Teardown recommendations, because carry out the Voluntary BGP Session Teardown recommendations, because
of the operational cost and risk of co-ordinating the two of the operational cost and risk of co-ordinating the two
configuration changes required. This has an adverse affect on configuration changes required. This has an adverse affect on
Internet performance. Internet performance.
In the absence notifications from the lower layer (e.g. ethernet link In the absence notifications from the lower layer (e.g. ethernet link
down) consistent with the planned maintenance activities in a down) consistent with the planned maintenance activities in a
switched layer-2 fabric, the Caretaker of the fabric could choose to switched layer-2 fabric, the Caretaker of the fabric could choose to
cull BGP sessions on behalf of the Operators connected to the fabric. cull BGP sessions on behalf of the Operators connected to the fabric.
Such culling of control-plane traffic will pre-empt the loss of end- Such culling of control-plane traffic will preempt the loss of end-
user traffic, by causing the expiration of BGP Hold Timers ahead of user traffic, by causing the expiration of BGP Hold Timers ahead of
the moment where the expiration would occur without intervention from the moment where the expiration would occur without intervention from
the fabric's Caretaker. the fabric's Caretaker.
In this scenario, BGP Session Culling is accomplished through the In this scenario, BGP Session Culling is accomplished through the
application of a combined layer-3 and layer-4 packet filter deployed application of a combined layer-3 and layer-4 packet filter deployed
in the switched fabric itself. in the switched fabric itself.
3.2.1. Packet Filter Considerations 3.2.1. Packet Filter Considerations
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maintenance. To prevent unnecessarily troubleshooting, it is maintenance. To prevent unnecessarily troubleshooting, it is
RECOMMENDED that Caretakers notify the affected operators before the RECOMMENDED that Caretakers notify the affected operators before the
maintenance takes place, and make it explicit that the Involuntary maintenance takes place, and make it explicit that the Involuntary
BGP Session Culling methodology will be applied. BGP Session Culling methodology will be applied.
4. Acknowledgments 4. Acknowledgments
The authors would like to thank the following people for their The authors would like to thank the following people for their
contributions to this document: Saku Ytti, Greg Hankins, James contributions to this document: Saku Ytti, Greg Hankins, James
Bensley, Wolfgang Tremmel, Daniel Roesen, Bruno Decraene, Tore Bensley, Wolfgang Tremmel, Daniel Roesen, Bruno Decraene, Tore
Anderson and John Heasley. Anderson, John Heasley and Warren Kumari.
5. Security Considerations 5. Security Considerations
There are no security considerations. There are no security considerations.
6. IANA Considerations 6. IANA Considerations
This document has no actions for IANA. This document has no actions for IANA.
7. References 7. References
7.1. Normative References 7.1. 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,
<http://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, <https://www.rfc- DOI 10.17487/RFC4271, January 2006,
editor.org/info/rfc4271>. <https://www.rfc-editor.org/info/rfc4271>.
7.2. Informative References 7.2. Informative References
[I-D.ietf-grow-bgp-gshut] [I-D.ietf-grow-bgp-gshut]
Francois, P., Decraene, B., Pelsser, C., Patel, K., and C. Francois, P., Decraene, B., Pelsser, C., Patel, K., and C.
Filsfils, "Graceful BGP session shutdown", draft-ietf- Filsfils, "Graceful BGP session shutdown", draft-ietf-
grow-bgp-gshut-09 (work in progress), July 2017. grow-bgp-gshut-09 (work in progress), July 2017.
[I-D.ietf-idr-shutdown] [I-D.ietf-idr-shutdown]
Snijders, J., Heitz, J., and J. Scudder, "BGP Snijders, J., Heitz, J., and J. Scudder, "BGP
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