draft-ietf-ospf-mpls-elc-07.txt   draft-ietf-ospf-mpls-elc-08.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 29, 2019 Expires: November 14, 2019
S. Sivabalan P. Psenak
C. Filsfils C. Filsfils
Cisco Cisco
S. Litkowski S. Litkowski
Orange Orange
September 25, 2018 May 13, 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-07 draft-ietf-ospf-mpls-elc-08
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 of processing ELs, referred to as Entropy Label has the capability of processing 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), in the cases where stacked as Entropy Readable Label Depth (ERLD), in the cases where stacked
LSPs are used for whatever reasons. This document defines mechanisms LSPs are used. This document defines a mechanisms to signal these
to signal these two capabilities using OSPF. These mechanisms are two capabilities using OSPF and OSPFv3. These mechanisms are
useful when the label advertisement is also done via OSPF. In particularly useful in the environment where Segment Routing (SR) is
addition, this document introduces the Non-IGP Functional used, where label advertisements are done via protocols like OSPF and
Capabilities TLV for advertising OSPF router's actual non-IGP OSPFv3.
functional capabilities. ELC is one of such non-IGP functional
capabilities.
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", "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].
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
skipping to change at page 2, line 12 skipping to change at page 2, line 10
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on March 29, 2019. This Internet-Draft will expire on November 14, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 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
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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
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Non-OSPF Functional Capabilities TLV . . . . . . . . . . . . 3 3. Advertising ELC Using OSPF . . . . . . . . . . . . . . . . . 3
4. Advertising ELC Using OSPF . . . . . . . . . . . . . . . . . 4 3.1. Advertising ELC Using OSPFv2 . . . . . . . . . . . . . . 4
5. Advertising ERLD Using OSPF . . . . . . . . . . . . . . . . . 4 3.2. Advertising ELC Using OSPFv3 . . . . . . . . . . . . . . 4
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5 4. Advertising ERLD Using OSPF . . . . . . . . . . . . . . . . . 4
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
8. Security Considerations . . . . . . . . . . . . . . . . . . . 5 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 7. Security Considerations . . . . . . . . . . . . . . . . . . . 5
9.1. Normative References . . . . . . . . . . . . . . . . . . 5 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
9.2. Informative References . . . . . . . . . . . . . . . . . 6 8.1. Normative References . . . . . . . . . . . . . . . . . . 5
8.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction 1. Introduction
[RFC6790] describes a method to load balance Multiprotocol Label [RFC6790] describes a method to load balance Multiprotocol Label
Switching (MPLS) traffic flows using Entropy Labels (EL). [RFC6790] Switching (MPLS) traffic flows using Entropy Labels (EL). It also
introduces the concept of Entropy Label Capability (ELC) and defines introduces the concept of Entropy Label Capability (ELC) and defines
the signalings of this capability via MPLS signaling protocols. the signalings of this capability via MPLS signaling protocols.
Recently, mechanisms are being defined to signal labels via link- Recently, mechanisms are being defined to signal labels via link-
state Interior Gateway Protocols (IGP) such as OSPF state Interior Gateway Protocols (IGP) such as OSPF
[I-D.ietf-ospf-segment-routing-extensions]. In such scenario, the [I-D.ietf-ospf-segment-routing-extensions]. In such scenario, the
signaling mechanisms defined in [RFC6790] are inadequate. This draft signaling mechanisms defined in [RFC6790] are inadequate. This draft
defines a mechanism to signal the ELC [RFC6790] using OSPF. This defines a mechanism to signal the ELC using OSPF. This mechanism is
mechanism is useful when the label advertisement is also done via useful when the label advertisement is also done via OSPF.
OSPF.
In addition, in the cases where stacked LSPs are used for whatever In addition, in the cases where stacked LSPs are used for whatever
reasons (e.g., SR-MPLS [I-D.ietf-spring-segment-routing-mpls]), it reasons (e.g., SR-MPLS [I-D.ietf-spring-segment-routing-mpls]), it
would be useful for ingress LSRs to know each intermediate LSR's would be useful for ingress LSRs to know each intermediate LSR's
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 whether it's necessary to insert an EL for a given LSP of determine whether it's necessary to insert an EL for a given LSP of
the stacked LSP tunnel in the case where there has already been at the stacked LSP tunnel in the case where there has already been at
least one EL in the label stack [I-D.ietf-mpls-spring-entropy-label]. least one EL in the label stack [I-D.ietf-mpls-spring-entropy-label].
2. Terminology 2. Terminology
This memo makes use of the terms defined in [RFC6790] and [RFC7770]. This memo makes use of the terms defined in [RFC6790] and [RFC7770].
3. Non-OSPF Functional Capabilities TLV 3. Advertising ELC Using OSPF
This document defines the Router Non-IGP Functional Capabilities TLV
with TLV type code of TBD1 within the body of the OSPF Router
Information LSA. An OSPF router advertising an OSPF RI LSA MAY
include the Router Non-IGP Functional Capabilities TLV. If included,
it MUST be included in the first instance of the LSA. Additionally,
the TLV MUST reflect the advertising OSPF router's actual non-IGP
functional capabilities in the flooding scope of the containing OSPF
RI LSA.
The format of the Router Non-OSPF Functional Capabilities TLV is as Even though ELC is a property of the node, in some cases it is
follows: advantageous to associate and advertise the ELC with the prefix. In
multi-area network, routers may not know the identity of the prefix
originator in the remote area, or may not know the capabilities of
such originator. Similarly in the multi domain network, the identity
of the prefix originator and its capabilities may not be known to the
ingress LSR.
0 1 2 3 If a router has multiple line cards, the router MUST NOT announce ELC
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 unless all of its linecards are capable of processing ELs.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=TBD1 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Non-IGP Functional Capabilities |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Non-OSPF Functional Capabilities TLV Format
Type: TBD1. If the router support ELs on all of its line cards, it SHOULD
advertise the ELC with every local host prefix it advertises in OSPF.
Length: Indicates the length of the value portion in octets and When an OSPF Area Border Router (ABR) advertises the prefix to the
will be a multiple of 4 octets dependent on the number of connected area based on the intra-area or inter-area prefix that is
capabilities advertised. Initially, the length will be 4, reachable in some other area, it MUST preserve the ELC signalling for
denoting 4 octets of Non-IGP Functional Capabilities Bits as such prefix.
defined in [I-D.ietf-isis-mpls-elc].
Value: contains the Non-IGP Functional Capabilities Bits as When an OSPF Autonomous System Boundary Router (ASBR) redistributes
defined in [I-D.ietf-isis-mpls-elc]. the prefix from other instance of the OSPF or from some other
protocol, it SHOULD preserve the ELC signalling for the prefix.
Exact mechanism on how to exchange ELC between protocol instances on
the ASBR is outside of the scope of this document and is
implementation specific.
The Non-IGP Functional Capabilities TLV MAY be followed by optional 3.1. Advertising ELC Using OSPFv2
TLVs that further specify a non-OSPF functional capability. In
contrast to the OSPF Router Functional Capabilities TLV, the non-OSPF
functional capabilities advertised in this TLV have no impact on the
OSPF protocol operation. The specifications for non-IGP functional
capabilities advertised in this TLV MUST describe protocol behavior
and address backwards compatibility.
4. Advertising ELC Using OSPF [RFC7684] defines the OSPFv2 Extended Prefix TLV to advertise
additional attributes associated with the prefix. The OSPFv2
Extended Prefix TLV includes a one octet Flags field. A new bit in
the Flags field is used to signal the ELC for the prefix:
One bit of the Non-IGP Functional Capability Bits for is used to 0x20 - E-Flag (ELC Flag): Set by the advertising router to
indicate the ELC. indicate that the prefix originator is capable of processing ELs
Assignment of a Non-IGP Functional Capability Bit for the ELC is 3.2. Advertising ELC Using OSPFv3
defined in [I-D.ietf-isis-mpls-elc].
If a router has multiple line cards, the router MUST NOT announce the [RFC5340] defines the OSPFv3 PrefixOptions that is advertised along
ELC [RFC6790] unless all of its linecards are capable of processing with the prefix. A new bit in the OSPFV3 PrefixOptions is used to
ELs. signal the ELC for the prefix:
How to apply the ELC advertisement to the inter-area, inter-AS and 0x04 - E-Flag (ELC Flag): Set by the advertising router to
inter-protocol scenarios is outside the scope of this document. indicate that the prefix originator is capable of processing ELs
5. Advertising ERLD Using OSPF 4. Advertising ERLD Using OSPF
A new MSD-type of the Node MSD sub-TLV A new MSD-type of the Node MSD sub-TLV
[I-D.ietf-isis-segment-routing-msd], called ERLD is defined to [I-D.ietf-isis-segment-routing-msd], called ERLD is defined to
advertise the ERLD of a given router. The scope of the advertisement advertise the ERLD of a given router. The 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 linecards with different capabilities of If a router has multiple linecards with different capabilities of
reading the maximum label stack deepth, the router MUST advertise the reading the maximum label stack deepth, the router MUST advertise the
smallest one. smallest one.
6. Acknowledgements 5. Acknowledgements
The authors would like to thank Yimin Shen, George Swallow, Acee The authors would like to thank Yimin Shen, George Swallow, Acee
Lindem, Les Ginsberg, Ketan Talaulikar, Jeff Tantsura , Bruno Lindem, Les Ginsberg, Ketan Talaulikar, Jeff Tantsura , Bruno
Decraene and Carlos Pignataro for their valuable comments. Decraene and Carlos Pignataro for their valuable comments.
7. IANA Considerations 6. IANA Considerations
This document requests IANA to allocate one TLV type from the OSPF RI This document requests IANA to allocate one bit from the OSPFv2
TLVs registry for the Non-IGP Functional CapabilitiesTLV. Extended Prefix TLV Flags registry:
8. Security Considerations 0x20 - E-Flag (ELC Flag)
This document requests IANA to allocate one bit from the OSPFv3
Prefix Options registry:
0x04 - E-Flag (ELC Flag)
7. Security Considerations
The security considerations as described in [RFC7770] is applicable The security considerations as described in [RFC7770] is applicable
to this document. This document does not introduce any new security to this document. This document does not introduce any new security
risk. risk.
9. References 8. References
9.1. Normative References 8.1. Normative References
[I-D.ietf-isis-mpls-elc] [I-D.ietf-isis-mpls-elc]
Xu, X., Kini, S., Sivabalan, S., Filsfils, C., and S. Xu, X., Kini, S., Sivabalan, S., 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-05 (work in progress), July 2018. elc-06 (work in progress), September 2018.
[I-D.ietf-isis-segment-routing-msd] [I-D.ietf-isis-segment-routing-msd]
Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg, Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg,
"Signaling MSD (Maximum SID Depth) using IS-IS", draft- "Signaling MSD (Maximum SID Depth) using IS-IS", draft-
ietf-isis-segment-routing-msd-16 (work in progress), ietf-isis-segment-routing-msd-19 (work in progress),
September 2018. October 2018.
[I-D.ietf-ospf-segment-routing-extensions] [I-D.ietf-ospf-segment-routing-extensions]
Psenak, P., Previdi, S., Filsfils, C., Gredler, H., Psenak, P., Previdi, S., Filsfils, C., Gredler, H.,
Shakir, R., Henderickx, W., and J. Tantsura, "OSPF Shakir, R., Henderickx, W., and J. Tantsura, "OSPF
Extensions for Segment Routing", draft-ietf-ospf-segment- Extensions for Segment Routing", draft-ietf-ospf-segment-
routing-extensions-25 (work in progress), April 2018. routing-extensions-27 (work in progress), December 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-14 data plane", draft-ietf-spring-segment-routing-mpls-22
(work in progress), June 2018. (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,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, DOI 10.17487/RFC5305, October Engineering", RFC 5305, DOI 10.17487/RFC5305, October
2008, <https://www.rfc-editor.org/info/rfc5305>. 2008, <https://www.rfc-editor.org/info/rfc5305>.
[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
<https://www.rfc-editor.org/info/rfc5340>.
[RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and [RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and
L. Yong, "The Use of Entropy Labels in MPLS Forwarding", L. Yong, "The Use of Entropy Labels in MPLS Forwarding",
RFC 6790, DOI 10.17487/RFC6790, November 2012, RFC 6790, DOI 10.17487/RFC6790, November 2012,
<https://www.rfc-editor.org/info/rfc6790>. <https://www.rfc-editor.org/info/rfc6790>.
[RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W.,
Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute
Advertisement", RFC 7684, DOI 10.17487/RFC7684, November
2015, <https://www.rfc-editor.org/info/rfc7684>.
[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>.
9.2. Informative References 8.2. Informative References
[I-D.ietf-mpls-spring-entropy-label] [I-D.ietf-mpls-spring-entropy-label]
Kini, S., Kompella, K., Sivabalan, S., Litkowski, S., Kini, S., Kompella, K., Sivabalan, S., Litkowski, S.,
Shakir, R., and J. Tantsura, "Entropy label for SPRING Shakir, R., and J. Tantsura, "Entropy label for SPRING
tunnels", draft-ietf-mpls-spring-entropy-label-12 (work in tunnels", draft-ietf-mpls-spring-entropy-label-12 (work in
progress), July 2018. progress), July 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
Email: sriganeshkini@gmail.com Email: sriganeshkini@gmail.com
Siva Sivabalan Peter Psenak
Cisco Cisco
Email: msiva@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 Orange
Email: stephane.litkowski@orange.com Email: stephane.litkowski@orange.com
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