Use of Multipath with MPLS and MPLS Transport Profile (MPLS-TP)
RFC 7190
Internet Engineering Task Force (IETF) C. Villamizar
Request for Comments: 7190 Outer Cape Cod Network Consulting
Category: Informational March 2014
ISSN: 2070-1721
Use of Multipath with MPLS and MPLS Transport Profile (MPLS-TP)
Abstract
Many MPLS implementations have supported multipath techniques, and
many MPLS deployments have used multipath techniques, particularly in
very high-bandwidth applications, such as provider IP/MPLS core
networks. MPLS Transport Profile (MPLS-TP) has strongly discouraged
the use of multipath techniques. Some degradation of MPLS-TP
Operations, Administration, and Maintenance (OAM) performance cannot
be avoided when operating over many types of multipath
implementations.
Using MPLS Entropy Labels (RFC 6790), MPLS Label Switched Paths
(LSPs) can be carried over multipath links while also providing a
fully MPLS-TP-compliant server layer for MPLS-TP LSPs. This document
describes the means of supporting MPLS as a server layer for MPLS-TP.
The use of MPLS-TP LSPs as a server layer for MPLS LSPs is also
discussed.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
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). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see 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/rfc7190.
Villamizar Informational [Page 1]
RFC 7190 MPLS and MPLS-TP Multipath March 2014
Copyright Notice
Copyright (c) 2014 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
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. MPLS as a Server Layer for MPLS-TP . . . . . . . . . . . . . 5
3.1. MPLS-TP Forwarding and Server-Layer Requirements . . . . 5
3.2. Methods of Supporting MPLS-TP Client LSPs over MPLS . . . 7
4. MPLS-TP as a Server Layer for MPLS . . . . . . . . . . . . . 11
5. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
7. Security Considerations . . . . . . . . . . . . . . . . . . . 13
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
8.1. Normative References . . . . . . . . . . . . . . . . . . 13
8.2. Informative References . . . . . . . . . . . . . . . . . 13
1. Introduction
Today the requirement to handle large aggregations of traffic can be
met by a number of techniques that we will collectively call
"multipath". Multipath applied to parallel links between the same
set of nodes includes Ethernet Link Aggregation [IEEE-802.1AX], link
bundling [RFC4201], or other aggregation techniques, some of which
could be vendor specific. Multipath applied to diverse paths rather
than parallel links includes Equal-Cost Multipath (ECMP) as applied
to OSPF, IS-IS, or BGP, and equal-cost Label Switched Paths (LSPs).
Some vendors support load splitting across equal-cost MPLS LSPs where
the load is split proportionally to the reserved bandwidth of the set
of LSPs.
RFC 5654 requirement 33 requires the capability to carry a client
MPLS Transport Profile (MPLS-TP) or MPLS layer over a server MPLS-TP
or MPLS layer [RFC5654]. This is possible in all cases with one
exception. When an MPLS LSP exceeds the capacity of any single
Villamizar Informational [Page 2]
RFC 7190 MPLS and MPLS-TP Multipath March 2014
component link, it MAY be carried by a network using multipath
techniques, but it SHOULD NOT be carried by a single MPLS-TP LSP due
to the inherent MPLS-TP capacity limitation imposed by MPLS-TP
Operations, Administration, and Maintenance (OAM) fate-sharing
Show full document text