Internet DRAFT - draft-xu-mpls-el-capability-signaling-igp
draft-xu-mpls-el-capability-signaling-igp
Network Working Group X. Xu
Internet-Draft Huawei
Intended status: Standards Track S. Kini
Expires: March 10, 2014 Ericsson
S. Sivabalan
C. Filsfils
Cisco
September 06, 2013
Signaling Entropy Label Capability Using Interior Gateway Protocols
draft-xu-mpls-el-capability-signaling-igp-00
Abstract
Multi Protocol Label Switching (MPLS) has defined a mechanism to load
balance traffic flows using Entropy Labels (EL). An LSR inserts the
EL Indicator and the EL label only if the LSR that pops them has the
capability of processing them. This draft defines a mechanism to
signal that capability using link state Interior Gateway Protocols
(IGP). This mechanism is useful when the label advertisement is also
done via that IGP.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on March 10, 2014.
Copyright Notice
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2. Abbreviations and Terminology . . . . . . . . . . . . . . . . 3
3. Advertising ELC using OSPF . . . . . . . . . . . . . . . . . 3
4. Advertising ELC using ISIS . . . . . . . . . . . . . . . . . 3
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 3
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
7. Security Considerations . . . . . . . . . . . . . . . . . . . 3
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 3
8.1. Normative References . . . . . . . . . . . . . . . . . . 4
8.2. Informative References . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
Multi Protocol Label Switching (MPLS) has defined a method in
[RFC6790] to load balance traffic flows using Entropy Labels (EL).
An LSR inserts the EL Indicator and the EL only if the LSR that pops
those labels has the capability of recognizing and processing them.
[RFC6790] defines the signaling of this capability (a.k.a Entropy
Label Capability - ELC) via signaling protocols. Recently,
mechanisms are being defined to signal labels via link state Interior
Gateway Protocols (IGP) such as OSPF
[I-D.psenak-ospf-segment-routing-extensions] and ISIS
[I-D.previdi-isis-segment-routing-extensions]. In such scenarios the
signaling mechanisms defined in [RFC6790] are inadequate. This draft
defines mechanisms to signal the ELC using the link state
advertisements (LSA) of the IGPs OSPF and ISIS. These capabilities
are advertised for the entire router and not just a single prefix.
This mechanism is useful when the label advertisement is also done
via that IGP.
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].
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2. Abbreviations and Terminology
This memo makes use of the terms defined in [RFC6790], [RFC4970] and
[RFC4971].
3. Advertising ELC using OSPF
The OSPF Router Information (RI) Opaque LSA defined in [RFC4970] is
used by OSPF routers to announce their capabilities. A new TLV
within the body of this LSA, called ELC TLV is defined to advertise
the capability of the router to process the ELI and EL. Its
formatting follows that described in sec 2.1 of [RFC4970]. This TLV
is applicable to both OSPFv2 and OSPFv3. The Type for the ELC TLV
needs to be assigned by IANA and it has a Length of zero. The scope
of the advertisement depends on the application but it is recommended
that it SHOULD be AS-scoped.
4. Advertising ELC using ISIS
The IS-IS Router CAPABILITY TLV defined in [RFC4971] is used by IS-IS
routers to announce their capabilities. A new sub-TLV of this TLV,
called ELC sub-TLV is defined to advertise the capability of the
router to process the ELI and EL. It is formatted as described in
[RFC5305] with a Type code to be assigned by IANA and a Length of
zero. The scope of the advertisement depends on the application but
it is recommended that it SHOULD be domain-wide.
5. Acknowledgements
The authors would like to thank TBD for their comments.
6. IANA Considerations
This memo includes requests to IANA to allocate a TLV type from the
OSPF RI TLVs registry and a sub-TLV type within the IS-IS Router
Capability TLV.
7. Security Considerations
This document does not introduce any new security considerations.
8. References
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8.1. Normative References
[I-D.previdi-isis-segment-routing-extensions]
Previdi, S., Filsfils, C., Bashandy, A., Gredler, H., and
S. Litkowski, "IS-IS Extensions for Segment Routing",
draft-previdi-isis-segment-routing-extensions-02 (work in
progress), July 2013.
[I-D.psenak-ospf-segment-routing-extensions]
Psenak, P., Previdi, S., Filsfils, C., Gredler, H., and R.
Shakir, "OSPF Extensions for Segment Routing", draft-
psenak-ospf-segment-routing-extensions-02 (work in
progress), July 2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4970] Lindem, A., Shen, N., Vasseur, JP., Aggarwal, R., and S.
Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 4970, July 2007.
[RFC4971] Vasseur, JP., Shen, N., and R. Aggarwal, "Intermediate
System to Intermediate System (IS-IS) Extensions for
Advertising Router Information", RFC 4971, July 2007.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, October 2008.
[RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and
L. Yong, "The Use of Entropy Labels in MPLS Forwarding",
RFC 6790, November 2012.
8.2. Informative References
[I-D.filsfils-rtgwg-segment-routing]
Filsfils, C., Previdi, S., Bashandy, A., Decraene, B.,
Litkowski, S., Horneffer, M., Milojevic, I., Shakir, R.,
Ytti, S., Henderickx, W., Tantsura, J., and E. Crabbe,
"Segment Routing Architecture", draft-filsfils-rtgwg-
segment-routing-00 (work in progress), June 2013.
Authors' Addresses
Xiaohu Xu
Huawei
Email: xuxiaohu@huawei.com
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Sriganesh Kini
Ericsson
Email: sriganesh.kini@ericsson.com
Siva Sivabalan
Cisco
Email: msiva@cisco.com
Clarence Filsfils
Cisco
Email: cfilsfil@cisco.com
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