MPLS Transport Profile (MPLS-TP) Next-Hop Ethernet Addressing
RFC 7213
Internet Engineering Task Force (IETF) D. Frost
Request for Comments: 7213 Blue Sun
Category: Standards Track S. Bryant
ISSN: 2070-1721 Cisco Systems
M. Bocci
Alcatel-Lucent
June 2014
MPLS Transport Profile (MPLS-TP) Next-Hop Ethernet Addressing
Abstract
The MPLS Transport Profile (MPLS-TP) is the set of MPLS protocol
functions applicable to the construction and operation of packet-
switched transport networks. This document presents considerations
for link-layer addressing of Ethernet frames carrying MPLS-TP
packets.
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/rfc7213.
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
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described in the Simplified BSD License.
Frost, et al. Standards Track [Page 1]
RFC 7213 MPLS-TP Ethernet Addressing June 2014
1. Introduction
The MPLS Transport Profile (MPLS-TP) [RFC5921] is the set of protocol
functions that meet the requirements [RFC5654] for the application of
MPLS to the construction and operation of packet-switched transport
networks. The MPLS-TP data plane consists of those MPLS-TP functions
concerned with the encapsulation and forwarding of MPLS-TP packets
and is described in [RFC5960].
This document presents considerations for link-layer addressing of
Ethernet frames carrying MPLS-TP packets. Since MPLS-TP packets are
MPLS packets, existing procedures ([RFC3032], [RFC5332]) for the
encapsulation of MPLS packets over Ethernet apply. Because IP
functionality is optional in an MPLS-TP network, IP-based protocols
for Media Access Control (MAC) address learning, such as the Address
Resolution Protocol (ARP) [RFC826] and IPv6 Neighbor Discovery
[RFC4861], may not be available. This document specifies the options
for the determination and selection of the next-hop Ethernet MAC
address when MPLS-TP is used between nodes that do not have an IP
data plane.
1.1. Terminology
Term Definition
------- ---------------------------
ARP Address Resolution Protocol
G-ACh Generic Associated Channel
LSP Label Switched Path
LSR Label Switching Router
MAC Media Access Control
MPLS-TP MPLS Transport Profile
Additional definitions and terminology can be found in [RFC5960] and
[RFC5654].
1.2. 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 [RFC2119].
2. Point-to-Point Link Addressing
When two MPLS-TP nodes are connected by a point-to-point Ethernet
link, the question arises as to what destination Ethernet Media
Access Control (MAC) address should be specified in Ethernet frames
transmitted to the peer node over the link. The problem of
determining this address does not arise in IP/MPLS networks because
Frost, et al. Standards Track [Page 2]
RFC 7213 MPLS-TP Ethernet Addressing June 2014
of the presence of the Ethernet Address Resolution Protocol (commonly
referred to as the Address Resolution Protocol and shortened to ARP)
[RFC826] or IPv6 Neighbor Discovery (ND) protocol [RFC4861], which
allow the unicast MAC address of the peer device to be learned
dynamically.
If existing mechanisms are available in an MPLS-TP network to
determine the destination unicast MAC addresses of peer nodes, for
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