This is a purely informative rendering of an RFC that includes verified errata. This rendering may not be used as a reference.
The following 'Verified' errata have been incorporated in this document:
EID 2533, EID 2534
Internet Engineering Task Force (IETF) D. Frost, Ed.
Request for Comments: 5960 S. Bryant, Ed.
Category: Standards Track Cisco Systems
ISSN: 2070-1721 M. Bocci, Ed.
Alcatel-Lucent
August 2010
MPLS Transport Profile Data Plane Architecture
Abstract
The Multiprotocol Label Switching Transport Profile (MPLS-TP) is the
set of MPLS protocol functions applicable to the construction and
operation of packet-switched transport networks. This document
specifies the subset of these functions that comprises the MPLS-TP
data plane: the architectural layer concerned with the encapsulation
and forwarding of packets within an MPLS-TP network.
This document is a product of a joint Internet Engineering Task Force
(IETF) / International Telecommunication Union Telecommunication
Standardization Sector (ITU-T) effort to include an MPLS Transport
Profile within the IETF MPLS and Pseudowire Emulation Edge-to-Edge
(PWE3) architectures to support the capabilities and functionalities
of a packet transport network.
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/rfc5960.
Copyright Notice
Copyright (c) 2010 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 . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
1.3. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. MPLS-TP Packet Encapsulation and Forwarding . . . . . . . . . 4
3. MPLS-TP Transport Entities . . . . . . . . . . . . . . . . . . 5
3.1. Label Switched Paths . . . . . . . . . . . . . . . . . . . 5
3.1.1. LSP Packet Encapsulation and Forwarding . . . . . . . 6
3.1.2. LSP Payloads . . . . . . . . . . . . . . . . . . . . . 7
3.1.3. LSP Types . . . . . . . . . . . . . . . . . . . . . . 7
3.2. Sections . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.3. Pseudowires . . . . . . . . . . . . . . . . . . . . . . . 9
4. MPLS-TP Generic Associated Channel . . . . . . . . . . . . . . 10
5. Server-Layer Considerations . . . . . . . . . . . . . . . . . 11
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.1. Normative References . . . . . . . . . . . . . . . . . . . 12
7.2. Informative References . . . . . . . . . . . . . . . . . . 14
1. Introduction
The MPLS Transport Profile (MPLS-TP) is the set of functions that
meet the requirements [RFC5654] for the application of MPLS to the
construction and operation of packet-switched transport networks.
MPLS-based packet-switched transport networks, and the overall
architecture of the MPLS-TP, are defined and described in [RFC5921].
It is assumed that the reader is familiar with that document.
This document defines the set of functions that comprise the MPLS-TP
data plane: the architectural layer concerned with the encapsulation
and forwarding of packets within an MPLS-TP network. This layer is
based on the data plane architectures for MPLS ([RFC3031] and
[RFC3032]) and for pseudowires [RFC3985].
This document is a product of a joint Internet Engineering Task Force
(IETF) / International Telecommunication Union Telecommunication
Standardization Sector (ITU-T) effort to include an MPLS Transport
Profile within the IETF MPLS and PWE3 architectures to support the
capabilities and functionalities of a packet transport network.
1.1. Scope
This document has the following purposes:
o To identify the data plane functions within the MPLS Transport
Profile; and
o To indicate which of these data plane functions an MPLS-TP
implementation is required to support.
This document defines the encapsulation and forwarding functions
applicable to packets traversing an MPLS-TP Label Switched Path
(LSP), pseudowire (PW), or section (see Section 3 for the definitions
of these transport entities). Encapsulation and forwarding functions
for packets outside an MPLS-TP LSP, PW, or section, and mechanisms
for delivering packets to or from MPLS-TP LSPs, PWs, and sections,
are outside the scope of this document.
1.2. Terminology
Term Definition
------- -------------------------------------------
ACH Associated Channel Header
G-ACh Generic Associated Channel
GAL G-ACh Label
LER Label Edge Router
LSE Label Stack Entry
LSP Label Switched Path
LSR Label Switching Router
MPLS-TP MPLS Transport Profile
OAM Operations, Administration, and Maintenance
PW Pseudowire
QoS Quality of Service
S-PE PW Switching Provider Edge
T-PE PW Terminating Provider Edge
TTL Time To Live
Additional definitions and terminology can be found in [RFC5921] and
[RFC5654].
1.3. 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].
2. MPLS-TP Packet Encapsulation and Forwarding
MPLS-TP packet encapsulation and forwarding SHALL operate according
to the MPLS data plane architecture described in [RFC3031] and
[RFC3032] and to the data plane architectures for single-segment
pseudowires and multi-segment pseudowires (see Section 3.3), except
as noted otherwise in this document. The MPLS-TP data plane
satisfies the requirements specified in [RFC5654].
Since an MPLS-TP packet is an MPLS packet as defined in [RFC3031] and
[RFC3032], it will have an associated label stack, and the 'push',
'pop', and 'swap' label processing operations specified in those
documents apply. The label stack represents a hierarchy of Label
Switched Paths (LSPs). A label is pushed to introduce an additional
level of LSP hierarchy and popped to remove it. Such an additional
level may be introduced by any pair of LSRs, whereupon they become
adjacent at this new level, and are then known as Label Edge Routers
(LERs) with respect to the new LSP.
In contrast to, for example, Section 3.10 of [RFC3031], support for
Internet Protocol (IP) host and router data plane functionality by
MPLS-TP interfaces and in MPLS-TP networks is OPTIONAL.
MPLS-TP forwarding is based on the label that identifies an LSP or
PW. The label value specifies the processing operation to be
performed by the next hop at that level of encapsulation. A swap of
this label is an atomic operation in which the contents of the packet
(after the swapped label) are opaque to the forwarding function. The
only event that interrupts a swap operation is Time To Live (TTL)
expiry.
At an LSR, S-PE, or T-PE, further processing to determine the context
of a packet occurs when a swap operation is interrupted by TTL
expiry. If the TTL of an LSP label expires, then the label with the
S (Bottom of Stack) bit set is inspected to determine if it is a
reserved label. If it is a reserved label, the packet is processed
according to the rules of that reserved label. For example, if it is
a Generic Associated Channel Label (GAL), then it is processed as a
packet on the Generic Associated Channel (G-ACh); see Section 4. If
the TTL of a PW expires at an S-PE or T-PE, then the packet is
examined to determine if a Generic Associated Channel Header (ACH) is
present immediately below the PW label. If so, then the packet is
processed as a packet on the G-ACh.
Similarly, if a pop operation at an LER exposes a reserved label at
the top of the label stack, then the packet is processed according to
the rules of that reserved label.
If no such exception occurs, the packet is forwarded according to the
procedures in [RFC3031] and [RFC3032].
3. MPLS-TP Transport Entities
The MPLS Transport Profile includes the following data plane
transport entities:
o Label Switched Paths (LSPs)
o sections
o pseudowires (PWs)
3.1. Label Switched Paths
MPLS-TP LSPs are ordinary MPLS LSPs as defined in [RFC3031], except
as specifically noted otherwise in this document.
3.1.1. LSP Packet Encapsulation and Forwarding
Encapsulation and forwarding of packets traversing MPLS-TP LSPs MUST
follow standard MPLS packet encapsulation and forwarding as defined
in [RFC3031], [RFC3032], [RFC5331], and [RFC5332], except as
explicitly stated otherwise in this document.
Data plane Quality of Service capabilities are included in the
MPLS-TP in the form of Traffic Engineered (TE) LSPs [RFC3209] and the
MPLS Differentiated Services (Diffserv) architecture [RFC3270]. Both
E-LSP and L-LSP MPLS Diffserv modes are included. The Traffic Class
field (formerly the EXP field) of an MPLS label follows the
definition of [RFC5462] and [RFC3270] and MUST be processed according
to the rules specified in those documents.
Except for transient packet reordering that may occur, for example,
during fault conditions, packets are delivered in order on L-LSPs,
and on E-LSPs within a specific ordered aggregate.
The Uniform, Pipe, and Short Pipe Diffserv tunneling and TTL
processing models described in [RFC3270] and [RFC3443] MAY be used
for MPLS-TP LSPs. Note, however, that support for the Pipe or Short
Pipe models is REQUIRED for typical transport applications in which
the topology and QoS characteristics of the MPLS-TP server layer are
independent of the client layer. Specific applications MAY place
further requirements on the Diffserv tunneling and TTL processing
models an LSP can use.
Per-platform, per-interface, or other context-specific label space
[RFC5331] MAY be used for MPLS-TP LSPs. Downstream [RFC3031] or
upstream [RFC5331] label allocation schemes MAY be used for MPLS-TP
LSPs. The requirements of a particular LSP type may, however,
dictate which label spaces or allocation schemes LSPs of that type
can use.
Equal-Cost Multi-Path (ECMP) load-balancing MUST NOT be performed on
an MPLS-TP LSP. MPLS-TP LSPs as defined in this document MAY operate
over a server layer that supports load-balancing, but this load-
balancing MUST operate in such a manner that it is transparent to
MPLS-TP. This does not preclude the future definition of new MPLS-TP
LSP types that have different requirements regarding the use of ECMP
in the server layer.
Penultimate Hop Popping (PHP) MUST be disabled by default on MPLS-TP
LSPs.
3.1.2. LSP Payloads
The MPLS-TP includes support for the following LSP payload types:
o Network-layer protocol packets (including MPLS-labeled packets)
o Pseudowire packets
The rules for processing LSP payloads that are network-layer protocol
packets SHALL be as specified in [RFC3032].
The rules for processing LSP payloads that are pseudowire packets
SHALL be as defined in the data plane pseudowire specifications (see
Section 3.3).
The payload of an MPLS-TP LSP may be a packet that itself contains an
MPLS label stack. This is true, for instance, when the payload is a
pseudowire or an MPLS LSP. In such cases, the label stack is
contiguous between the MPLS-TP LSP and its payload, and exactly one
LSE in this stack SHALL have the S (Bottom of Stack) bit set to 1.
This behavior reflects best current practice in MPLS but differs
slightly from [RFC3032], which uses the S bit to identify when MPLS
label processing stops and network-layer processing starts.
3.1.3. LSP Types
The MPLS-TP includes the following LSP types:
o Point-to-point unidirectional
o Point-to-point associated bidirectional
o Point-to-point co-routed bidirectional
o Point-to-multipoint unidirectional
Point-to-point unidirectional LSPs are supported by the basic MPLS
architecture [RFC3031] and are REQUIRED to function in the same
manner in the MPLS-TP data plane, except as explicitly stated
otherwise in this document.
A point-to-point associated bidirectional LSP between LSRs A and B
consists of two unidirectional point-to-point LSPs, one from A to B
and the other from B to A, which are regarded as a pair providing a
single logical bidirectional transport path.
A point-to-point co-routed bidirectional LSP is a point-to-point
associated bidirectional LSP with the additional constraint that its
two unidirectional component LSPs in each direction follow the same
path (in terms of both nodes and links). An important property of
co-routed bidirectional LSPs is that their unidirectional component
LSPs share fate.
A point-to-multipoint unidirectional LSP functions in the same manner
in the data plane, with respect to basic label processing and packet-
switching operations, as a point-to-point unidirectional LSP, with
one difference: an LSR may have more than one (egress interface,
outgoing label) pair associated with the LSP, and any packet it
transmits on the LSP is transmitted out all associated egress
interfaces. Point-to-multipoint LSPs are described in [RFC4875] and
[RFC5332]. TTL processing and exception handling for point-to-
multipoint LSPs is the same as for point-to-point LSPs and is
described in Section 2.
3.2. Sections
Two MPLS-TP LSRs are considered to be topologically adjacent at a
particular layer n >= 0 of the MPLS-TP LSP hierarchy if there exists
connectivity between them at the next lowest network layer, and if
there is no MPLS layer processing at layer n between the two LSRs
(other than at the LSRs themselves). Such connectivity, if it
exists, will be either an MPLS-TP LSP (if n > 0) or a data-link
provided by the underlying server layer network (if n = 0), and is
referred to as an MPLS-TP section at layer n of the MPLS-TP LSP
hierarchy. Thus, the links traversed by a layer n+1 MPLS-TP LSP are
layer n MPLS-TP sections. Such an LSP is referred to as a client of
the section layer, and the section layer is referred to as the server
layer with respect to its clients.
The MPLS label stack associated with an MPLS-TP section at layer n
consists of n labels, in the absence of stack optimization
mechanisms. In order for two LSRs to exchange non-IP MPLS-TP control
packets over a section, an additional label, the G-ACh Label (GAL)
(see Section 4) MUST appear at the bottom of the label stack.
An MPLS-TP section may provide one or more of the following types of
service to its client layer:
o Point-to-point bidirectional
o Point-to-point unidirectional
o Point-to-multipoint unidirectional
The manner in which a section provides such a service is outside the
scope of the MPLS-TP.
An LSP of any of the types listed in Section 3.1.3 may serve as a
section for a client-layer transport entity as long as it supports
the type of service the client requires.
A section MUST provide a means of identifying the type of payload it
carries. This mechanism may be used to facilitate multiplexing MPLS
with other protocols on the section if that function is supported by
the section. Support or non-support of multiplexing on sections is
out-of-scope for this document.
If the section is a data-link, link-specific mechanisms
such as a protocol type indication in the data-link header MAY be
used. If the section is an LSP, this information MAY be implied by
the LSP label or, if the LSP payload is MPLS-labeled, by the setting
of the S bit. Additional labels MAY also be used if necessary to
distinguish different payload types; see [RFC5921] for examples and
further discussion.
EID 2533 (Verified) is as follows:Section: 3.2
Original Text:
A section MUST provide a means of identifying the type of payload it
carries. If the section is a data-link, link-specific mechanisms
such as a protocol type indication in the data-link header MAY be
used. If the section is an LSP, this information MAY be implied by
the LSP label or, if the LSP payload is MPLS-labeled, by the setting
of the S bit. Additional labels MAY also be used if necessary to
distinguish different payload types; see [RFC5921] for examples and
further discussion.
Corrected Text:
A section MUST provide a means of identifying the type of payload it
carries. This mechanism may be used to facilitate multiplexing MPLS
with other protocols on the section if that function is supported by
the section. Support or non-support of multiplexing on sections is
out-of-scope for this document.
If the section is a data-link, link-specific mechanisms
such as a protocol type indication in the data-link header MAY be
used. If the section is an LSP, this information MAY be implied by
the LSP label or, if the LSP payload is MPLS-labeled, by the setting
of the S bit. Additional labels MAY also be used if necessary to
distinguish different payload types; see [RFC5921] for examples and
further discussion.
Notes:
This change clarifies the requirement to support payload identification, the way it is used, and the use to which it is put. Furthermore, it clarifies the standing of protocol multiplexing onto underlying sections.
This issue was first raised in a liaison from the ITU-T See https://datatracker.ietf.org/liaison/916/
3.3. Pseudowires
The data plane architectures for single-segment pseudowires [RFC3985]
and multi-segment pseudowires [RFC5659] are included in the MPLS-TP.
Data plane processing procedures for pseudowires are defined and
described in a number of IETF documents. Some example pseudowire
data plane procedures include:
o Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for Use over
an MPLS PSN [RFC4385]
o Encapsulation Methods for Transport of Ethernet over MPLS Networks
[RFC4448]
o Structure-Agnostic Time Division Multiplexing (TDM) over Packet
(SAToP) [RFC4553]
o Encapsulation Methods for Transport of PPP/High-Level Data Link
Control (HDLC) over MPLS Networks [RFC4618]
o Encapsulation Methods for Transport of Frame Relay over
Multiprotocol Label Switching (MPLS) Networks [RFC4619]
o Encapsulation Methods for Transport of Asynchronous Transfer Mode
(ATM) over MPLS Networks [RFC4717]
o Pseudowire Emulation Edge-to-Edge (PWE3) Asynchronous Transfer
Mode (ATM) Transparent Cell Transport Service [RFC4816]
o Synchronous Optical Network/Synchronous Digital Hierarchy (SONET/
SDH) Circuit Emulation over Packet (CEP) [RFC4842]
o Structure-Aware Time Division Multiplexed (TDM) Circuit Emulation
Service over Packet Switched Network (CESoPSN) [RFC5086]
o Time Division Multiplexing over IP (TDMoIP) [RFC5087]
o Encapsulation Methods for Transport of Fibre Channel frames Over
MPLS Networks [FC-ENCAP]
This document specifies no modifications or extensions to pseudowire
data plane architectures or protocols.
4. MPLS-TP Generic Associated Channel
The MPLS Generic Associated Channel (G-ACh) mechanism is specified in
[RFC5586] and included in the MPLS-TP. The G-ACh provides an
auxiliary logical data channel associated with MPLS-TP sections,
LSPs, and PWs in the data plane. The primary purpose of the G-ACh in
the context of MPLS-TP is to support control, management, and
Operations, Administration, and Maintenance (OAM) traffic associated
with MPLS-TP transport entities. The G-ACh MUST NOT be used to
transport client layer network traffic in MPLS-TP networks.
For pseudowires, the G-ACh uses the first four bits of the PW control
word to provide the initial discrimination between data packets and
packets belonging to the associated channel, as described in
[RFC4385]. When this first nibble of a packet, immediately following
the label at the bottom of stack, has a value of '1', then this
packet belongs to a G-ACh. The first 32 bits following the bottom of
stack label then have a defined format called an Associated Channel
Header (ACH), which further defines the content of the packet. The
ACH is therefore both a demultiplexer for G-ACh traffic on the PW,
and a discriminator for the type of G-ACh traffic.
When the control message is carried over a section or an LSP, rather
than over a PW, it is necessary to provide an indication in the
packet that the payload is something other than a client data packet.
This is achieved by including a reserved label with a value of 13 at
the bottom of the label stack. This reserved label is referred to as
the G-ACh Label (GAL) and is defined in [RFC5586]. When a GAL is
found, it indicates that the payload begins with an ACH. The GAL is
thus a demultiplexer for G-ACh traffic on the section or the LSP, and
the ACH is a discriminator for the type of traffic carried on the
G-ACh. MPLS-TP forwarding follows the normal MPLS model, and thus a
GAL is invisible to an LSR unless it is the top label in the label
stack. The only other circumstance under which the label stack may
be inspected for a GAL is when the TTL has expired. Normal packet
forwarding MAY continue concurrently with this inspection. All
operations on the label stack are in accordance with [RFC3031] and
[RFC3032].
An application processing a packet received over the G-ACh may
require packet-specific context (such as the receiving interface or
received label stack). Data plane implementations MUST therefore
provide adequate context to the application that is to process a
G-ACh packet. The definition of the context required MUST be
provided as part of the specification of the application using the
G-ACh.
5. Server-Layer Considerations
The MPLS-TP network has no awareness of the internals of the server
layer of which it is a client; it requires only that the server layer
be capable of delivering the type of service required by the MPLS-TP
transport entities that make use of it. Note that what appears to be
a single server-layer link to the MPLS-TP network may be a
complicated construct underneath, such as an LSP or a collection of
underlying links operating as a bundle. Special care may be needed
in network design and operation when such constructs are used as a
server layer for MPLS-TP.
Encapsulation of MPLS-TP packets for transport over specific server-
layer media is outside the scope of this document.
6. Security Considerations
The MPLS data plane (and therefore the MPLS-TP data plane) does not
provide any security mechanisms in and of itself. Client layers that
wish to secure data carried over MPLS-TP transport entities are
REQUIRED to apply their own security mechanisms.
Where management or control plane protocols are used to install
label-switching operations necessary to establish MPLS-TP transport
paths, those protocols are equipped with security features that
network operators may use to securely create the transport paths.
Where enhanced security is desirable, and a trust relationship exists
between two LSRs, an LSR receiving an MPLS packet MAY choose to
implement an additional policy for processing the received packet as
follows:
The receiving LSR discards the packet unless every MPLS label
stack entry that it processes from the packet's label stack has a
label that has been agreed for use by the sender of the packet
(for example, is a reserved label or has been distributed using
the management plane or control plane upstream or downstream
allocation).
EID 2534 (Verified) is as follows:Section: 6
Original Text:
Where enhanced security is desirable, and a trust relationship exists
between an LSR and its peer, the LSR MAY choose to implement the
following policy for the processing of MPLS packets received from one
or more of its neighbors:
Upon receipt of an MPLS packet, discard the packet unless one of
the following two conditions holds:
1. Any MPLS label in the packet's label stack processed at the
receiving LSR, such as an LSP or PW label, has a label value
that the receiving LSR has distributed to that neighbor; or
2. Any MPLS label in the packet's label stack processed at the
receiving LSR, such as an LSP or PW label, has a label value
that the receiving LSR has previously distributed to the peer
beyond that neighbor (i.e., when it is known that the path
from the system to which the label was distributed to the
receiving system is via that neighbor).
Corrected Text:
Where enhanced security is desirable, and a trust relationship exists
between two LSRs, an LSR receiving an MPLS packet MAY choose to
implement an additional policy for processing the received packet as
follows:
The receiving LSR discards the packet unless every MPLS label
stack entry that it processes from the packet's label stack has a
label that has been agreed for use by the sender of the packet
(for example, is a reserved label or has been distributed using
the management plane or control plane upstream or downstream
allocation).
Notes:
There was considerable confusion about the distinction between peer and neighbour. This was first raised in a liaison from the ITU-T visible at https://datatracker.ietf.org/liaison/916/
Clarification was also added about which labels are acceptable.
This does not result in a technical change to the specification, but introduces clarity about the processes described.
Further details of MPLS and MPLS-TP security can be found in
[RFC5921] and [RFC5920].
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031, January 2001.
[RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
Encoding", RFC 3032, January 2001.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.
[RFC3270] Le Faucheur, F., Wu, L., Davie, B., Davari, S., Vaananen,
P., Krishnan, R., Cheval, P., and J. Heinanen, "Multi-
Protocol Label Switching (MPLS) Support of Differentiated
Services", RFC 3270, May 2002.
[RFC3443] Agarwal, P. and B. Akyol, "Time To Live (TTL) Processing
in Multi-Protocol Label Switching (MPLS) Networks",
RFC 3443, January 2003.
[RFC4385] Bryant, S., Swallow, G., Martini, L., and D. McPherson,
"Pseudowire Emulation Edge-to-Edge (PWE3) Control Word
for Use over an MPLS PSN", RFC 4385, February 2006.
[RFC4448] Martini, L., Rosen, E., El-Aawar, N., and G. Heron,
"Encapsulation Methods for Transport of Ethernet over
MPLS Networks", RFC 4448, April 2006.
[RFC4553] Vainshtein, A. and YJ. Stein, "Structure-Agnostic Time
Division Multiplexing (TDM) over Packet (SAToP)",
RFC 4553, June 2006.
[RFC4618] Martini, L., Rosen, E., Heron, G., and A. Malis,
"Encapsulation Methods for Transport of PPP/High-Level
Data Link Control (HDLC) over MPLS Networks", RFC 4618,
September 2006.
[RFC4619] Martini, L., Kawa, C., and A. Malis, "Encapsulation
Methods for Transport of Frame Relay over Multiprotocol
Label Switching (MPLS) Networks", RFC 4619,
September 2006.
[RFC4717] Martini, L., Jayakumar, J., Bocci, M., El-Aawar, N.,
Brayley, J., and G. Koleyni, "Encapsulation Methods for
Transport of Asynchronous Transfer Mode (ATM) over MPLS
Networks", RFC 4717, December 2006.
[RFC4816] Malis, A., Martini, L., Brayley, J., and T. Walsh,
"Pseudowire Emulation Edge-to-Edge (PWE3) Asynchronous
Transfer Mode (ATM) Transparent Cell Transport Service",
RFC 4816, February 2007.
[RFC4842] Malis, A., Pate, P., Cohen, R., and D. Zelig,
"Synchronous Optical Network/Synchronous Digital
Hierarchy (SONET/SDH) Circuit Emulation over Packet
(CEP)", RFC 4842, April 2007.
[RFC4875] Aggarwal, R., Papadimitriou, D., and S. Yasukawa,
"Extensions to Resource Reservation Protocol - Traffic
Engineering (RSVP-TE) for Point-to-Multipoint TE Label
Switched Paths (LSPs)", RFC 4875, May 2007.
[RFC5331] Aggarwal, R., Rekhter, Y., and E. Rosen, "MPLS Upstream
Label Assignment and Context-Specific Label Space",
RFC 5331, August 2008.
[RFC5332] Eckert, T., Rosen, E., Aggarwal, R., and Y. Rekhter,
"MPLS Multicast Encapsulations", RFC 5332, August 2008.
[RFC5462] Andersson, L. and R. Asati, "Multiprotocol Label
Switching (MPLS) Label Stack Entry: "EXP" Field Renamed
to "Traffic Class" Field", RFC 5462, February 2009.
[RFC5586] Bocci, M., Vigoureux, M., and S. Bryant, "MPLS Generic
Associated Channel", RFC 5586, June 2009.
[RFC5654] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N.,
and S. Ueno, "Requirements of an MPLS Transport Profile",
RFC 5654, September 2009.
7.2. Informative References
[FC-ENCAP] Black, D. and L. Dunbar, "Encapsulation Methods for
Transport of Fibre Channel frames Over MPLS Networks",
Work in Progress, June 2010.
[RFC3985] Bryant, S. and P. Pate, "Pseudo Wire Emulation Edge-to-
Edge (PWE3) Architecture", RFC 3985, March 2005.
[RFC5086] Vainshtein, A., Sasson, I., Metz, E., Frost, T., and P.
Pate, "Structure-Aware Time Division Multiplexed (TDM)
Circuit Emulation Service over Packet Switched Network
(CESoPSN)", RFC 5086, December 2007.
[RFC5087] Stein, Y(J)., Shashoua, R., Insler, R., and M. Anavi,
"Time Division Multiplexing over IP (TDMoIP)", RFC 5087,
December 2007.
[RFC5659] Bocci, M. and S. Bryant, "An Architecture for Multi-
Segment Pseudowire Emulation Edge-to-Edge", RFC 5659,
October 2009.
[RFC5920] Fang, L., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, July 2010.
[RFC5921] Bocci, M., Bryant, S., Frost, D., Levrau, L., and L.
Berger, "A Framework for MPLS in Transport Networks",
RFC 5921, July 2010.
Authors' Addresses
Dan Frost (editor)
Cisco Systems
EMail: danfrost@cisco.com
Stewart Bryant (editor)
Cisco Systems
EMail: stbryant@cisco.com
Matthew Bocci (editor)
Alcatel-Lucent
EMail: matthew.bocci@alcatel-lucent.com