draft-ietf-ospf-mpls-elc-09.txt   draft-ietf-ospf-mpls-elc-10.txt 
OSPF Working Group X. Xu OSPF Working Group X. Xu
Internet-Draft Alibaba Inc Internet-Draft Alibaba Inc
Intended status: Standards Track S. Kini Intended status: Standards Track S. Kini
Expires: March 6, 2020 Expires: April 6, 2020
P. Psenak P. Psenak
C. Filsfils C. Filsfils
Cisco
S. Litkowski S. Litkowski
Orange Cisco
September 3, 2019 October 4, 2019
Signaling Entropy Label Capability and Entropy Readable Label-stack Signaling Entropy Label Capability and Entropy Readable Label-stack
Depth Using OSPF Depth Using OSPF
draft-ietf-ospf-mpls-elc-09 draft-ietf-ospf-mpls-elc-10
Abstract Abstract
Multiprotocol Label Switching (MPLS) has defined a mechanism to load- Multiprotocol Label Switching (MPLS) has defined a mechanism to load-
balance traffic flows using Entropy Labels (EL). An ingress Label balance traffic flows using Entropy Labels (EL). An ingress Label
Switching Router (LSR) cannot insert ELs for packets going into a Switching Router (LSR) cannot insert ELs for packets going into a
given tunnel unless an egress LSR has indicated via signaling that it given tunnel unless an egress LSR has indicated via signaling that it
has the capability to process ELs, referred to as Entropy Label has the capability to process ELs, referred to as Entropy Label
Capability (ELC), on that tunnel. In addition, it would be useful Capability (ELC), on that tunnel. In addition, it would be useful
for ingress LSRs to know each LSR's capability of reading the maximum for ingress LSRs to know each LSR's capability of reading the maximum
label stack depth and performing EL-based load-balancing, referred to label stack depth and performing EL-based load-balancing, referred to
as Entropy Readable Label Depth (ERLD). This document defines a as Entropy Readable Label Depth (ERLD). This document defines a
mechanism to signal these two capabilities using OSPF and OSPFv3. mechanism to signal these two capabilities using OSPF and OSPFv3.
These mechanism is particularly useful in the environment where These mechanism is particularly useful in the environment where
Segment Routing (SR) is used, where label advertisements are done via Segment Routing (SR) is used, where label advertisements are done via
protocols like OSPF and OSPFv3. protocols like OSPF and OSPFv3.
Requirements Language 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", "NOT RECOMMENDED", "MAY", and
document are to be interpreted as described in RFC 2119 [RFC2119]. "OPTIONAL" in this document are to be interpreted as described in
[BCP14] [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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 https://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 March 6, 2020. This Internet-Draft will expire on April 6, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2019 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
(https://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
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Advertising ELC Using OSPF . . . . . . . . . . . . . . . . . 3 3. Advertising ELC Using OSPF . . . . . . . . . . . . . . . . . 3
3.1. Advertising ELC Using OSPFv2 . . . . . . . . . . . . . . 4 3.1. Advertising ELC Using OSPFv2 . . . . . . . . . . . . . . 4
3.2. Advertising ELC Using OSPFv3 . . . . . . . . . . . . . . 4 3.2. Advertising ELC Using OSPFv3 . . . . . . . . . . . . . . 4
4. Advertising ERLD Using OSPF . . . . . . . . . . . . . . . . . 4 4. Advertising ERLD Using OSPF . . . . . . . . . . . . . . . . . 4
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 5. Signaling ELC and ERLD in BGP-LS . . . . . . . . . . . . . . 4
6. BGP-LS Extension . . . . . . . . . . . . . . . . . . . . . . 4 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
8. Security Considerations . . . . . . . . . . . . . . . . . . . 5 8. Security Considerations . . . . . . . . . . . . . . . . . . . 5
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
9.1. Normative References . . . . . . . . . . . . . . . . . . 5 9.1. Normative References . . . . . . . . . . . . . . . . . . 5
9.2. Informative References . . . . . . . . . . . . . . . . . 7 9.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction 1. Introduction
[RFC6790] describes a method to load-balance Multiprotocol Label [RFC6790] describes a method to load-balance Multiprotocol Label
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capability of reading the maximum label stack depth and performing capability of reading the maximum label stack depth and performing
EL-based load-balancing. This capability, referred to as Entropy EL-based load-balancing. This capability, referred to as Entropy
Readable Label Depth (ERLD) as defined in Readable Label Depth (ERLD) as defined in
[I-D.ietf-mpls-spring-entropy-label] may be used by ingress LSRs to [I-D.ietf-mpls-spring-entropy-label] may be used by ingress LSRs to
determine the position of the EL label in the stack, and whether it's determine the position of the EL label in the stack, and whether it's
necessary to insert multiple ELs at different positions in the label necessary to insert multiple ELs at different positions in the label
stack. stack.
2. Terminology 2. Terminology
This document makes use of the terms defined in [RFC6790] and This document makes use of the terms defined in [RFC6790], [RFC7770]
[RFC7770]. and [I-D.ietf-mpls-spring-entropy-label].
3. Advertising ELC Using OSPF 3. Advertising ELC Using OSPF
Even though ELC is a property of the node, in some cases it is Even though ELC is a property of the node, in some cases it is
advantageous to associate and advertise the ELC with the prefix. In advantageous to associate and advertise the ELC with the prefix. In
multi-area networks, routers may not know the identity of the prefix multi-area networks, routers may not know the identity of the prefix
originator in a remote area, or may not know the capabilities of such originator in a remote area, or may not know the capabilities of such
originator. Similarly, in a multi domain network, the identity of originator. Similarly, in a multi domain network, the identity of
the prefix originator and its capabilities may not be known to the the prefix originator and its capabilities may not be known to the
ingress LSR. ingress LSR.
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[RFC5340] defines the OSPFv3 PrefixOptions that are advertised along [RFC5340] defines the OSPFv3 PrefixOptions that are advertised along
with the prefix. A new bit in the OSPFV3 PrefixOptions is used to with the prefix. A new bit in the OSPFV3 PrefixOptions is used to
signal the ELC for the prefix: signal the ELC for the prefix:
0x04 - E-Flag (ELC Flag): Set by the advertising router to 0x04 - E-Flag (ELC Flag): Set by the advertising router to
indicate that the prefix originator is capable of processing ELs. indicate that the prefix originator is capable of processing ELs.
4. Advertising ERLD Using OSPF 4. Advertising ERLD Using OSPF
A new MSD-type of the Node MSD sub-TLV A new MSD (Maximum SID Depth) type of the Node MSD sub-TLV [RFC8476],
[I-D.ietf-isis-segment-routing-msd], called ERLD is defined to called ERLD is defined to advertise the ERLD of a given router. The
advertise the ERLD of a given router. The scope of the advertisement scope of the advertisement depends on the application.
depends on the application.
Assignment of a MSD-Type for ERLD is defined in Assignment of a MSD-Type for ERLD is defined in
[I-D.ietf-isis-mpls-elc]. [I-D.ietf-isis-mpls-elc].
If a router has multiple line-cards with different capabilities for If a router has multiple line-cards with different capabilities for
reading the maximum label stack depth, the router MUST advertise the reading the maximum label stack depth, the router MUST advertise the
smallest one. smallest one.
5. Acknowledgements When the ERLD MSD-Type is received in the OSPFv2 or OSPFv3 Link MSD
Sub-TLV, it MUST be ignored.
The authors would like to thank Yimin Shen, George Swallow, Acee
Lindem, Les Ginsberg, Ketan Talaulikar, Jeff Tantsura , Bruno
Decraene and Carlos Pignataro for their valuable comments.
6. BGP-LS Extension 5. Signaling ELC and ERLD in BGP-LS
The OSPF extensions defined in this document can be advertised via The OSPF extensions defined in this document can be advertised via
BGP-LS [RFC7752] using existing BGP-LS TLVs. BGP-LS [RFC7752] using existing BGP-LS TLVs.
The ELC Flag included in the OSPFv2 Extended Prefix TLV and the The ELC Flag included in the OSPFv2 Extended Prefix TLV and the
OSPFv3 PrefixOptions, as defined in Section 3, is advertised using OSPFv3 PrefixOptions, as defined in Section 3, is advertised using
the Prefix Attribute Flags TLV (TLV 1170) of the BGP-LS IPv4/IPv6 the Prefix Attribute Flags TLV (TLV 1170) of the BGP-LS IPv4/IPv6
Prefix NLRI Attribute as defined in section 2.3.2 of Prefix NLRI Attribute as defined in section 2.3.2 of
[I-D.ietf-idr-bgp-ls-segment-routing-ext]. [I-D.ietf-idr-bgp-ls-segment-routing-ext].
The ERLD MSD-type introduced for OSPF in Section 4 is advertised The ERLD MSD-type introduced for OSPF in Section 4 is advertised
using the Node MSD TLV (TLV 266) of the BGP-LS Node NLRI Attribute as using the Node MSD TLV (TLV 266) of the BGP-LS Node NLRI Attribute as
defined in section 3 of [I-D.ietf-idr-bgp-ls-segment-routing-ext]. defined in section 3 of [I-D.ietf-idr-bgp-ls-segment-routing-msd].
6. Acknowledgements
The authors would like to thank Yimin Shen, George Swallow, Acee
Lindem, Les Ginsberg, Ketan Talaulikar, Jeff Tantsura , Bruno
Decraene and Carlos Pignataro for their valuable comments.
7. IANA Considerations 7. IANA Considerations
This document requests IANA to allocate one flag from the OSPFv2 This document requests IANA to allocate one flag from the OSPFv2
Extended Prefix TLV Flags registry: Extended Prefix TLV Flags registry:
0x20 - E-Flag (ELC Flag) 0x20 - E-Flag (ELC Flag)
This document requests IANA to allocate one flag from the OSPFv3 This document requests IANA to allocate one flag from the OSPFv3
Prefix Options registry: Prefix Options registry:
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8. Security Considerations 8. Security Considerations
The security considerations as described in [RFC7770] and The security considerations as described in [RFC7770] and
[I-D.ietf-mpls-spring-entropy-label] are applicable to this document. [I-D.ietf-mpls-spring-entropy-label] are applicable to this document.
Incorrectly setting the E flag (ELC capable) (during origination, Incorrectly setting the E flag (ELC capable) (during origination,
inter-area advertisement or redistribution) may lead to black-holing inter-area advertisement or redistribution) may lead to black-holing
of the traffic on the egress node. of the traffic on the egress node.
Incorrectly setting of the ERLD value may lead to poor load-balancing
of the traffic.
9. References 9. References
9.1. Normative References 9.1. Normative References
[BCP14] , <https://tools.ietf.org/html/bcp14>.
[I-D.ietf-idr-bgp-ls-segment-routing-ext] [I-D.ietf-idr-bgp-ls-segment-routing-ext]
Previdi, S., Talaulikar, K., Filsfils, C., Gredler, H., Previdi, S., Talaulikar, K., Filsfils, C., Gredler, H.,
and M. Chen, "BGP Link-State extensions for Segment and M. Chen, "BGP Link-State extensions for Segment
Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-16 Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-16
(work in progress), June 2019. (work in progress), June 2019.
[I-D.ietf-idr-bgp-ls-segment-routing-msd]
Tantsura, J., Chunduri, U., Talaulikar, K., Mirsky, G.,
and N. Triantafillis, "Signaling MSD (Maximum SID Depth)
using Border Gateway Protocol Link-State", draft-ietf-idr-
bgp-ls-segment-routing-msd-08 (work in progress),
September 2019.
[I-D.ietf-isis-mpls-elc] [I-D.ietf-isis-mpls-elc]
Xu, X., Kini, S., Psenak, P., Filsfils, C., and S. Xu, X., Kini, S., Psenak, P., Filsfils, C., and S.
Litkowski, "Signaling Entropy Label Capability and Entropy Litkowski, "Signaling Entropy Label Capability and Entropy
Readable Label Depth Using IS-IS", draft-ietf-isis-mpls- Readable Label Depth Using IS-IS", draft-ietf-isis-mpls-
elc-07 (work in progress), May 2019. elc-08 (work in progress), September 2019.
[I-D.ietf-isis-segment-routing-msd]
Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg,
"Signaling MSD (Maximum SID Depth) using IS-IS", draft-
ietf-isis-segment-routing-msd-19 (work in progress),
October 2018.
[I-D.ietf-ospf-segment-routing-extensions] [I-D.ietf-mpls-spring-entropy-label]
Psenak, P., Previdi, S., Filsfils, C., Gredler, H., Kini, S., Kompella, K., Sivabalan, S., Litkowski, S.,
Shakir, R., Henderickx, W., and J. Tantsura, "OSPF Shakir, R., and J. Tantsura, "Entropy label for SPRING
Extensions for Segment Routing", draft-ietf-ospf-segment- tunnels", draft-ietf-mpls-spring-entropy-label-12 (work in
routing-extensions-27 (work in progress), December 2018. progress), July 2018.
[I-D.ietf-spring-segment-routing-mpls] [I-D.ietf-spring-segment-routing-mpls]
Bashandy, A., Filsfils, C., Previdi, S., Decraene, B., Bashandy, A., Filsfils, C., Previdi, S., Decraene, B.,
Litkowski, S., and R. Shakir, "Segment Routing with MPLS Litkowski, S., and R. Shakir, "Segment Routing with MPLS
data plane", draft-ietf-spring-segment-routing-mpls-22 data plane", draft-ietf-spring-segment-routing-mpls-22
(work in progress), May 2019. (work in progress), May 2019.
[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,
skipping to change at page 7, line 5 skipping to change at page 7, line 16
S. Ray, "North-Bound Distribution of Link-State and S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752, Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016, DOI 10.17487/RFC7752, March 2016,
<https://www.rfc-editor.org/info/rfc7752>. <https://www.rfc-editor.org/info/rfc7752>.
[RFC7770] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and [RFC7770] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and
S. Shaffer, "Extensions to OSPF for Advertising Optional S. Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 7770, DOI 10.17487/RFC7770, Router Capabilities", RFC 7770, DOI 10.17487/RFC7770,
February 2016, <https://www.rfc-editor.org/info/rfc7770>. February 2016, <https://www.rfc-editor.org/info/rfc7770>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8476] Tantsura, J., Chunduri, U., Aldrin, S., and P. Psenak,
"Signaling Maximum SID Depth (MSD) Using OSPF", RFC 8476,
DOI 10.17487/RFC8476, December 2018,
<https://www.rfc-editor.org/info/rfc8476>.
9.2. Informative References 9.2. Informative References
[I-D.ietf-mpls-spring-entropy-label] [I-D.ietf-ospf-segment-routing-extensions]
Kini, S., Kompella, K., Sivabalan, S., Litkowski, S., Psenak, P., Previdi, S., Filsfils, C., Gredler, H.,
Shakir, R., and J. Tantsura, "Entropy label for SPRING Shakir, R., Henderickx, W., and J. Tantsura, "OSPF
tunnels", draft-ietf-mpls-spring-entropy-label-12 (work in Extensions for Segment Routing", draft-ietf-ospf-segment-
progress), July 2018. routing-extensions-27 (work in progress), December 2018.
Authors' Addresses Authors' Addresses
Xiaohu Xu Xiaohu Xu
Alibaba Inc Alibaba Inc
Email: xiaohu.xxh@alibaba-inc.com Email: xiaohu.xxh@alibaba-inc.com
Sriganesh Kini Sriganesh Kini
skipping to change at page 7, line 28 skipping to change at page 8, line 4
Email: xiaohu.xxh@alibaba-inc.com Email: xiaohu.xxh@alibaba-inc.com
Sriganesh Kini Sriganesh Kini
Email: sriganeshkini@gmail.com Email: sriganeshkini@gmail.com
Peter Psenak Peter Psenak
Cisco Cisco
Email: ppsenak@cisco.com Email: ppsenak@cisco.com
Clarence Filsfils Clarence Filsfils
Cisco Cisco
Email: cfilsfil@cisco.com Email: cfilsfil@cisco.com
Stephane Litkowski Stephane Litkowski
Orange Cisco
Email: stephane.litkowski@orange.com Email: sslitkows@cisco.com
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