The Use of Entropy Labels in MPLS Forwarding
RFC 6790
Internet Engineering Task Force (IETF) K. Kompella
Request for Comments: 6790 J. Drake
Updates: 3031, 3107, 3209, 5036 Juniper Networks
Category: Standards Track S. Amante
ISSN: 2070-1721 Level 3 Communications, Inc.
W. Henderickx
Alcatel-Lucent
L. Yong
Huawei USA
November 2012
The Use of Entropy Labels in MPLS Forwarding
Abstract
Load balancing is a powerful tool for engineering traffic across a
network. This memo suggests ways of improving load balancing across
MPLS networks using the concept of "entropy labels". It defines the
concept, describes why entropy labels are useful, enumerates
properties of entropy labels that allow maximal benefit, and shows
how they can be signaled and used for various applications. This
document updates RFCs 3031, 3107, 3209, and 5036.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6790.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
Kompella, et al. Standards Track [Page 1]
RFC 6790 MPLS Entropy Labels November 2012
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
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described in the Simplified BSD License.
Table of Contents
1. Introduction ....................................................3
1.1. Conventions Used ...........................................4
1.2. Motivation .................................................6
2. Approaches ......................................................7
3. Entropy Labels and Their Structure ..............................8
4. Data Plane Processing of Entropy Labels .........................9
4.1. Egress LSR .................................................9
4.2. Ingress LSR ...............................................10
4.3. Transit LSR ...............................................11
4.4. Penultimate Hop LSR .......................................12
5. Signaling for Entropy Labels ...................................12
5.1. LDP Signaling .............................................12
5.1.1. Processing the ELC TLV .............................13
5.2. BGP Signaling .............................................13
5.3. RSVP-TE Signaling .........................................14
5.4. Multicast LSPs and Entropy Labels .........................15
6. Operations, Administration, and Maintenance (OAM) and
Entropy Labels .................................................15
7. MPLS-TP and Entropy Labels .....................................16
8. Entropy Labels in Various Scenarios ............................16
8.1. LDP Tunnel ................................................17
8.2. LDP over RSVP-TE ..........................................20
8.3. MPLS Applications .........................................20
9. Security Considerations ........................................20
10. IANA Considerations ...........................................21
10.1. Reserved Label for ELI ...................................21
10.2. LDP Entropy Label Capability TLV .........................21
10.3. BGP Entropy Label Capability Attribute ...................21
10.4. RSVP-TE Entropy Label Capability Flag ....................22
11. Acknowledgments ...............................................22
12. References ....................................................22
12.1. Normative References .....................................22
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