draft-ietf-mpls-tp-gach-gal-04.txt   draft-ietf-mpls-tp-gach-gal-05.txt 
MPLS Working Group M. Bocci, Ed. MPLS Working Group M. Bocci, Ed.
Internet-Draft M. Vigoureux, Ed. Internet-Draft M. Vigoureux, Ed.
Updates: 3032, 4385, 5085 Alcatel-Lucent Updates: 3032, 4385, 5085 Alcatel-Lucent
(if approved) G. Swallow (if approved) G. Swallow
Intended status: Standards Track D. Ward Intended status: Standards Track D. Ward
Expires: November 1, 2009 S. Bryant Expires: November 17, 2009 S. Bryant
Cisco Cisco
R. Aggarwal R. Aggarwal
Juniper Networks Juniper Networks
April 30, 2009 May 16, 2009
MPLS Generic Associated Channel MPLS Generic Associated Channel
draft-ietf-mpls-tp-gach-gal-04 draft-ietf-mpls-tp-gach-gal-05
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
skipping to change at page 1, line 38 skipping to change at page 1, line 38
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on November 1, 2009. This Internet-Draft will expire on November 17, 2009.
Copyright Notice Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents in effect on the date of Provisions Relating to IETF Documents in effect on the date of
publication of this document (http://trustee.ietf.org/license-info). publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
skipping to change at page 2, line 16 skipping to change at page 2, line 16
This document generalizes the applicability of the pseudowire (PW) This document generalizes the applicability of the pseudowire (PW)
Associated Channel Header (ACH), enabling the realization of a Associated Channel Header (ACH), enabling the realization of a
control channel associated to MPLS Label Switched Paths (LSPs) and control channel associated to MPLS Label Switched Paths (LSPs) and
MPLS Sections in addition to MPLS pseudowires. In order to identify MPLS Sections in addition to MPLS pseudowires. In order to identify
the presence of this Associated Channel Header in the label stack, the presence of this Associated Channel Header in the label stack,
this document also assigns one of the reserved MPLS label values to this document also assigns one of the reserved MPLS label values to
the Generic Associated Channel Label (GAL), to be used as a label the Generic Associated Channel Label (GAL), to be used as a label
based exception mechanism. based exception mechanism.
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 [1].
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Contributing Authors . . . . . . . . . . . . . . . . . . . 5 1.1. Objectives . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Objectives . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.3. Requirements Language and Terminology . . . . . . . . . . 5
1.4. Terminology . . . . . . . . . . . . . . . . . . . . . . . 6 2. Generic Associated Channel Header . . . . . . . . . . . . . . 5
2. Generic Associated Channel Header . . . . . . . . . . . . . . 6
2.1. Definition . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1. Definition . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2. Allocation of Channel Types . . . . . . . . . . . . . . . 7 2.2. Allocation of Channel Types . . . . . . . . . . . . . . . 6
3. ACH TLVs . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3. ACH TLVs . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1. ACH TLV Payload Structure . . . . . . . . . . . . . . . . 8 3.1. ACH TLV Payload Structure . . . . . . . . . . . . . . . . 7
3.2. ACH TLV Header . . . . . . . . . . . . . . . . . . . . . . 9 3.2. ACH TLV Header . . . . . . . . . . . . . . . . . . . . . . 8
3.3. ACH TLV Object . . . . . . . . . . . . . . . . . . . . . . 9 3.3. ACH TLV Object . . . . . . . . . . . . . . . . . . . . . . 8
4. Generalized Exception Mechanism . . . . . . . . . . . . . . . 10 4. Generalized Exception Mechanism . . . . . . . . . . . . . . . 9
4.1. Relationship with Existing MPLS OAM Alert Mechanisms . . . 10 4.1. Relationship with Existing MPLS OAM Alert Mechanisms . . . 9
4.2. GAL Applicability and Usage . . . . . . . . . . . . . . . 11 4.2. GAL Applicability and Usage . . . . . . . . . . . . . . . 10
4.2.1. GAL Processing . . . . . . . . . . . . . . . . . . . . 11 4.2.1. GAL Processing . . . . . . . . . . . . . . . . . . . . 10
4.3. Relationship with RFC 3429 . . . . . . . . . . . . . . . . 14 4.3. Relationship with RFC 3429 . . . . . . . . . . . . . . . . 13
5. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 14 5. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 14
6. Congestion Considerations . . . . . . . . . . . . . . . . . . 15 6. Congestion Considerations . . . . . . . . . . . . . . . . . . 15
7. Security Considerations . . . . . . . . . . . . . . . . . . . 15 7. Contributing Authors . . . . . . . . . . . . . . . . . . . . . 15
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 15
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 17 9. Security Considerations . . . . . . . . . . . . . . . . . . . 15
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
10.1. Normative References . . . . . . . . . . . . . . . . . . . 17 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
10.2. Informative References . . . . . . . . . . . . . . . . . . 18 11.1. Normative References . . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19 11.2. Informative References . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction 1. Introduction
There is a need for Operations, Administration and Maintenance (OAM) There is a need for Operations, Administration and Maintenance (OAM)
mechanisms that can be used for fault detection, diagnostics, mechanisms that can be used for fault detection, diagnostics,
maintenance and other functions on a pseudowire (PW) and a Label maintenance and other functions on a pseudowire (PW) and a Label
Switched Path (LSP). These functions can be used between any two Switched Path (LSP). These functions can be used between any two
Label Edge Routers (LERs) / Label Switching Router (LSRs) or Label Edge Routers (LERs) / Label Switching Router (LSRs) or
Terminating Provider Edge routers (T-PEs) / Switching Provider Edge Terminating Provider Edge routers (T-PEs) / Switching Provider Edge
routers (S-PEs) along the path of an LSP or PW respectively [11]. routers (S-PEs) along the path of an LSP or PW respectively [11].
Some of these functions can be supported using existing tools such as Some of these functions can be supported using existing tools such as
Virtual Circuit Connectivity Verification (VCCV) [2], Bidirectional Virtual Circuit Connectivity Verification (VCCV) [1], Bidirectional
Forwarding Detection for MPLS LSPs (BFD-MPLS) [12], LSP-Ping [13], or Forwarding Detection for MPLS LSPs (BFD-MPLS) [12], LSP-Ping [13], or
BFD-VCCV [14]. However, a requirement has been indicated to augment BFD-VCCV [14]. However, a requirement has been indicated to augment
this set of maintenance functions, in particular when MPLS networks this set of maintenance functions, in particular when MPLS networks
are used for packet transport services and transport network are used for packet transport services and transport network
operations [15]. Examples of these functions include performance operations [15]. Examples of these functions include performance
monitoring, automatic protection switching, and support for monitoring, automatic protection switching, and support for
management and signaling communication channels. These tools MUST be management and signaling communication channels. These tools MUST be
applicable to, and function in essentially the same manner (from an applicable to, and function in essentially the same manner (from an
operational point of view) on MPLS PWs, MPLS LSPs and MPLS Sections. operational point of view) on MPLS PWs, MPLS LSPs and MPLS Sections.
They MUST also operate in-band on the PW or LSP such that they do not They MUST also operate in-band on the PW or LSP such that they do not
depend on Packet Switched Network (PSN) routing or on user traffic, depend on Packet Switched Network (PSN) routing or on user traffic,
and MUST also NOT depend on dynamic control plane functions. and MUST also NOT depend on dynamic control plane functions.
VCCV [2] can use an Associated Channel Header (ACH) to provide a PW- VCCV [1] can use an Associated Channel Header (ACH) to provide a PW
associated control channel between a PW's end points, over which OAM associated control channel between a PW's end points, over which OAM
and other control messages can be exchanged. This document and other control messages can be exchanged. This document
generalizes the applicability of the ACH to enable the same generalizes the applicability of the ACH to enable the same
associated control channel mechanism to be used for Sections, LSPs associated control channel mechanism to be used for Sections, LSPs
and PWs. The associated control channel thus generalized is known as and PWs. The associated control channel thus generalized is known as
the Generic Associated Channel (G-ACh). The ACH, specified in RFC the Generic Associated Channel (G-ACh). The ACH, specified in RFC
4385 [3], may be used with additional code points to support 4385 [2], may be used with additional code points to support
additional MPLS maintenance functions on the G-ACh. additional MPLS maintenance functions on the G-ACh.
Generalizing the applicability of the ACH to LSPs and Sections also Generalizing the applicability of the ACH to LSPs and Sections also
requires a method to identify that a packet contains an ACH followed requires a method to identify that a packet contains an ACH followed
by a non-service payload. Therefore, this document also defines a by a non-service payload. Therefore, this document also defines a
label based exception mechanism that serves to inform an LSR (or LER) label based exception mechanism that serves to inform an LSR (or LER)
that a packet it receives on an LSP or Section belongs to an that a packet it receives on an LSP or Section belongs to an
associated control channel. The label used for that purpose is one associated control channel. The label used for that purpose is one
of the MPLS reserved labels and is referred to as the GAL (G-ACh of the MPLS reserved labels and is referred to as the GAL (G-ACh
Label). The GAL mechanism is defined to work together with the ACH Label). The GAL mechanism is defined to work together with the ACH
for LSPs and MPLS Sections. for LSPs and MPLS Sections.
RFC 4379 [13] and BFD-MPLS [12] define alert mechanisms that enable RFC 4379 [13] and BFD-MPLS [12] define alert mechanisms that enable
an MPLS LSR to identify and process MPLS OAM packets when these are an MPLS LSR to identify and process MPLS OAM packets when these are
encapsulated in an IP header. These alert mechanisms are based, for encapsulated in an IP header. These alert mechanisms are based, for
example, on Time To Live (TTL) expiration and/or on the use of an IP example, on Time To Live (TTL) expiration and/or on the use of an IP
destination address in the range of 127/8 or 0:0:0:0:0:FFFF: destination address in the range of 127.0.0.0/8 or 0:0:0:0:0:FFFF:
127.0.0.0/104, respectively for IPv4 and IPv6. These mechanisms are 127.0.0.0/104, respectively for IPv4 and IPv6. These mechanisms are
the default mechanisms for identifying MPLS OAM packets when the default mechanisms for identifying MPLS OAM packets when
encapsulated in an IP header. However it may not always be possible encapsulated in an IP header. However it may not always be possible
to use these mechanisms in some MPLS applications e.g., MPLS to use these mechanisms in some MPLS applications e.g., MPLS
Transport Profile (MPLS-TP) [11], particularly when IP based Transport Profile (MPLS-TP) [11], particularly when IP based
demultiplexing cannot be used. This document defines a mechanism demultiplexing cannot be used. This document defines a mechanism
that is RECOMMENDED for identifying and encapsulating MPLS OAM and that is RECOMMENDED for identifying and encapsulating MPLS OAM and
other maintenance messages when IP based mechanisms such as those other maintenance messages when IP based mechanisms such as those
used in [13] and [12] are not available. Yet, this mechanism MAY be used in [13] and [12] are not available. Yet, this mechanism MAY be
used in addition to IP-based mechanisms. used in addition to IP-based mechanisms.
skipping to change at page 5, line 27 skipping to change at page 4, line 27
be understood in the broad sense. That is, a set of maintenance and be understood in the broad sense. That is, a set of maintenance and
management mechanisms that include OAM, Automatic Protection management mechanisms that include OAM, Automatic Protection
Switching (APS), Signaling Communication Channel (SCC) and Management Switching (APS), Signaling Communication Channel (SCC) and Management
Communication Channel (MCC) messages. Communication Channel (MCC) messages.
Also note that the GAL and ACH are applicable to MPLS and PWs in Also note that the GAL and ACH are applicable to MPLS and PWs in
general. This document specifies general mechanism and uses MPLS-TP general. This document specifies general mechanism and uses MPLS-TP
as an example application. The application of the GAL and ACH to as an example application. The application of the GAL and ACH to
other specific MPLS uses is outside the scope of this document. other specific MPLS uses is outside the scope of this document.
1.1. Contributing Authors 1.1. Objectives
The editors gratefully acknowledge the contributions of Sami Boutros,
Italo Busi, Marc Lasserre, Lieven Levrau and Siva Sivabalan
1.2. Objectives
This document defines a mechanism that provides a solution to the This document defines a mechanism that provides a solution to the
extended maintenance needs of emerging applications for MPLS. It extended maintenance needs of emerging applications for MPLS. It
creates a generic control channel mechanism that may be applied to creates a generic control channel mechanism that may be applied to
MPLS LSPs and Sections, while maintaining compatibility with the PW MPLS LSPs and Sections, while maintaining compatibility with the PW
associated channel. It also normalizes the use of the ACH for PWs in associated channel. It also normalizes the use of the ACH for PWs in
a transport context, and defines a label based exception mechanism to a transport context, and defines a label based exception mechanism to
alert LERs/LSRs of the presence of an ACH after the bottom of the alert LERs/LSRs of the presence of an ACH after the bottom of the
stack. label stack.
1.3. Scope 1.2. Scope
This document defines the encapsulation header for Sections, LSPs, This document defines the encapsulation header for Sections, LSPs,
and PWs associated control channel messages. and PWs associated control channel messages.
It does not define how associated control channel capabilities are It does not define how associated control channel capabilities are
signaled or negotiated between LERs/LSRs or PEs, or the operation of signaled or negotiated between LERs/LSRs or PEs, or the operation of
various OAM functions. various OAM functions.
This document does not deprecate existing MPLS and PW OAM mechanisms. This document does not deprecate existing MPLS and PW OAM mechanisms.
1.4. Terminology 1.3. Requirements Language and Terminology
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 [3].
This document uses the following additional terminology:
ACH: Associated Channel Header ACH: Associated Channel Header
G-ACh: Generic Associated Channel G-ACh: Generic Associated Channel
GAL: G-ACh Label GAL: G-ACh Label
G-ACh packet: Any packet containing a message belonging to a protocol G-ACh packet: Any packet containing a message belonging to a protocol
that is carried on a PW, LSP or MPLS Section associated control that is carried on a PW, LSP or MPLS Section associated control
channel. Examples include maintenance protocols such as OAM channel. Examples include maintenance protocols such as OAM
functions, signaling communications or management communications. functions, signaling communications or management communications.
The terms 'Section' and 'Concatenated Segment' are defined in [16] as The terms 'Section' and 'Concatenated Segment' are defined in [16] as
follows (note that the terms 'Section' and ''Section Layer Network' follows (note that the terms 'Section' and 'Section Layer Network'
are synonymous): are synonymous):
Concatenated Segment: A serial-compound link connection as defined in Concatenated Segment: A serial-compound link connection as defined in
[17]. A concatenated segment is a contiguous part of an LSP or [17]. A concatenated segment is a contiguous part of an LSP or
multi-segment PW that comprises a set of segments and their multi-segment PW that comprises a set of segments and their
interconnecting nodes in sequence. interconnecting nodes in sequence.
Section Layer Network: A section is a server layer (which may be Section Layer Network: A section is a server layer (which may be
MPLS-TP or a different technology) which provides for encapsulation MPLS-TP or a different technology) which provides for encapsulation
and OAM of a client layer network. A section layer may provide for and OAM of a client layer network. A section layer may provide for
aggregation of multiple MPLS-TP clients. Note that G.805 [17] aggregation of multiple MPLS-TP clients. Note that G.805 [17]
defines the section layer as one of the two layer networks in a defines the section layer as one of the two layer networks in a
transmission media layer network. The other layer network is the transmission media layer network. The other layer network is the
physical media layer network. physical media layer network.
2. Generic Associated Channel Header 2. Generic Associated Channel Header
VCCV [2] defines three Control Channel (CC) Types that may be used to VCCV [1] defines three Control Channel (CC) Types that may be used to
exchange OAM messages through a PW: CC Type 1 uses an ACH and is exchange OAM messages through a PW: CC Type 1 uses an ACH and is
referred to as "In-band VCCV"; CC Type 2 uses the MPLS Router Alert referred to as "In-band VCCV"; CC Type 2 uses the MPLS Router Alert
Label to indicate VCCV packets and is referred to as "Out of Band Label to indicate VCCV packets and is referred to as "Out of Band
VCCV"; CC Type 3 uses the TTL to force the packet to be processed by VCCV"; CC Type 3 uses the TTL to force the packet to be processed by
the targeted router control plane and is referred to as "MPLS PW the targeted router control plane and is referred to as "MPLS PW
Label with TTL == 1". Label with TTL == 1".
2.1. Definition 2.1. Definition
The use of the ACH, previously limited to PWs, is here generalized to The use of the ACH, previously limited to PWs, is here generalized to
also apply to LSPs and to Sections. Note that for PWs, the PWE3 also apply to LSPs and to Sections. Note that for PWs, the PWE3
control word [3] MUST be present in the encapsulation of user packets control word [2] MUST be present in the encapsulation of user packets
when the ACH is used to realize the associated control channel. when the ACH is used to realize the associated control channel.
The ACH used by CC Type 1 is depicted in figure below: The ACH used by CC Type 1 is depicted in figure below:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 1|Version| Reserved | Channel Type | |0 0 0 1|Version| Reserved | Channel Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Associated Channel Header Figure 1: Associated Channel Header
In the above figure, the first nibble is set to 0001b to indicate a In the above figure, the first nibble is set to 0001b to indicate a
control channel associated with a PW, an LSP or a Section. The control channel associated with a PW, an LSP or a Section. The
Version field is set to 0, as specified in RFC 4385 [3]. Bits 8 to Version field is set to 0, as specified in RFC 4385 [2]. Bits 8 to
15 of the ACH are reserved and MUST be set to 0 and ignored on 15 of the ACH are reserved and MUST be set to 0 and ignored on
reception. Bits 16 to 31 are used to encode the possible Channel reception. Bits 16 to 31 are used to encode the possible Channel
Types. Types.
Note that VCCV [2] also includes mechanisms for negotiating the Note that VCCV [1] also includes mechanisms for negotiating the
Control Channel and Connectivity Verification (i.e., OAM function) Control Channel and Connectivity Verification (i.e., OAM function)
Types between PEs. It is anticipated that similar mechanisms will be Types between PEs. It is anticipated that similar mechanisms will be
applied to LSPs. Such application will require further applied to LSPs. Such application will require further
specification. However, such specification is beyond the scope of specification. However, such specification is beyond the scope of
this document. this document.
The G-ACh MUST NOT be used to transport user traffic. The G-ACh MUST NOT be used to transport user traffic.
2.2. Allocation of Channel Types 2.2. Allocation of Channel Types
The Channel Type field indicates the type of message carried on the The Channel Type field indicates the type of message carried on the
associated control channel e.g., IPv4 or IPv6 if IP demultiplexing is associated control channel e.g., IPv4 or IPv6 if IP demultiplexing is
used for messages sent on the associated control channel, or OAM or used for messages sent on the associated control channel, or OAM or
other maintenance function if IP demultiplexing is not used. For other maintenance function if IP demultiplexing is not used. For
associated control channel packets where IP is not used as the associated control channel packets where IP is not used as the
multiplexer, the Channel Type indicates the specific protocol carried multiplexer, the Channel Type indicates the specific protocol carried
in the associated control channel. in the associated control channel.
Values for the Channel Type field currently used for VCCV are Values for the Channel Type field currently used for VCCV are
specified elsewhere e.g., in RFC 4446 [4] and RFC 4385 [3]. specified elsewhere e.g., in RFC 4446 [4] and RFC 4385 [2].
Additional Channel Type values and the associated maintenance Additional Channel Type values and the associated maintenance
functionality will be defined in other documents. Each document, functionality will be defined in other documents. Each document,
specifying a protocol solution relying on the ACH, MUST also specify specifying a protocol solution relying on the ACH, MUST also specify
the applicable Channel Type field value. the applicable Channel Type field value.
Note that these values are allocated from the PW Associated Channel Note that these values are allocated from the PW Associated Channel
Type registry [4], but this document modifies the existing policy to Type registry [4], but this document modifies the existing policy to
accommodate a level of experimentation. See Section 8 for further accommodate a level of experimentation. See Section 10 for further
details. details.
3. ACH TLVs 3. ACH TLVs
In some applications of the generalized associated control channel it In some applications of the generalized associated control channel it
is necessary to include one or more ACH TLVs to provide additional is necessary to include one or more ACH TLVs to provide additional
context information to the G-ACh packet. One use of these ACH TLVs context information to the G-ACh packet. One use of these ACH TLVs
might be to identify the source and/or intended destination of the might be to identify the source and/or intended destination of the
associated channel message. However, the use of this construct is associated channel message. However, the use of this construct is
not limited to providing addressing information nor is the not limited to providing addressing information nor is the
skipping to change at page 8, line 31 skipping to change at page 7, line 36
channel packet, but the Channel Type nevertheless defines that ACH channel packet, but the Channel Type nevertheless defines that ACH
TLVs MAY be used, an ACH TLV Header MUST be present but with a length TLVs MAY be used, an ACH TLV Header MUST be present but with a length
field set to zero to indicate that no ACH TLV follow this header. field set to zero to indicate that no ACH TLV follow this header.
If an ACH Channel Type specification does not explicitly specify that If an ACH Channel Type specification does not explicitly specify that
ACH TLVs MAY be used, then the ACH TLV Header MUST NOT be used. ACH TLVs MAY be used, then the ACH TLV Header MUST NOT be used.
3.1. ACH TLV Payload Structure 3.1. ACH TLV Payload Structure
This section defines and describes the structure of an ACH payload This section defines and describes the structure of an ACH payload
when an ACH TLV Header is present. The structure of ACH TLVs that when an ACH TLV Header is present.
MAY follow an ACH TLV Header is defined and described in the
following sections.
The following figure (Figure 2) shows the structure of a G-ACh packet The following figure (Figure 2) shows the structure of a G-ACh packet
payload. payload.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ACH | | ACH |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ACH TLV Header | | ACH TLV Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ~ | ~
~ zero or more ACH TLVs ~ ~ zero or more ACH TLVs ~
~ | ~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ~ | ~
~ G-ACh Message ~ ~ G-ACh Message ~
~ | ~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: ACH TLV Payload Structure Figure 2: G-ACh Packet Payload
3.2. ACH TLV Header 3.2. ACH TLV Header
The ACH TLV Header defines the length of the set of ACH TLVs that The ACH TLV Header defines the length of the set of ACH TLVs that
follow. follow.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | Reserved | | Length | Reserved |
skipping to change at page 9, line 44 skipping to change at page 8, line 44
The Length field specifies the length in octets of the complete set The Length field specifies the length in octets of the complete set
of TLVs including sub-TLVs that follow the ACH TLV header. A length of TLVs including sub-TLVs that follow the ACH TLV header. A length
of zero indicates that no ACH TLV follow this header. Note that no of zero indicates that no ACH TLV follow this header. Note that no
padding is required for the set of ACH TLVs. padding is required for the set of ACH TLVs.
The Reserved field is for future use and MUST be set to zero on The Reserved field is for future use and MUST be set to zero on
transmission and ignored on reception. transmission and ignored on reception.
3.3. ACH TLV Object 3.3. ACH TLV Object
The structure of ACH TLVs that MAY follow an ACH TLV Header is
defined and described in this section.
An ACH TLV consists of a 16-bit Type field, followed by a 16-bit An ACH TLV consists of a 16-bit Type field, followed by a 16-bit
Length field which specifies the number of octets of the Value field Length field which specifies the number of octets of the Value field
which follows the Length field. This 32-bit word is followed by zero which follows the Length field. This 32-bit word is followed by zero
or more octets of Value information. The format and semantics of the or more octets of Value information. The format and semantics of the
Value information are defined by the TLV Type as recorded in the TLV Value information are defined by the TLV Type as recorded in the TLV
Type registry. See Section 8 for further details. Note that the Type registry. See Section 10 for further details. Note that the
Value field of ACH TLVs MAY contain sub-TLVs. Note that no padding Value field of ACH TLVs MAY contain sub-TLVs. Note that no padding
is required for individual TLVs or sub-TLVs. is required for individual TLVs or sub-TLVs.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type | Length | | TLV Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ~ | ~
~ Value ~ ~ Value ~
skipping to change at page 10, line 25 skipping to change at page 9, line 27
Figure 4: ACH TLV Format Figure 4: ACH TLV Format
4. Generalized Exception Mechanism 4. Generalized Exception Mechanism
Generalizing the associated control channel mechanism to LSPs and Generalizing the associated control channel mechanism to LSPs and
Sections also requires a method to identify that a packet contains an Sections also requires a method to identify that a packet contains an
ACH followed by a non-service payload. This document specifies that ACH followed by a non-service payload. This document specifies that
a label is used for that purpose and calls this special label the a label is used for that purpose and calls this special label the
G-ACh Label (GAL). One of the reserved label values defined in RFC G-ACh Label (GAL). One of the reserved label values defined in RFC
3032 [5] is assigned for this purpose. The value of the label is to 3032 [5] is assigned for this purpose. The value of the label is to
be allocated by IANA; this document suggests the value 13. be allocated by IANA.
The GAL provides an alert based exception mechanism to: The GAL provides an alert based exception mechanism to:
o differentiate specific packets (i.e., G-ACh packets) from others, o differentiate specific packets (i.e., G-ACh packets) from others,
such as user-plane ones, such as user-plane ones,
o indicate that the ACH appears immediately after the bottom of the o indicate that the ACH appears immediately after the bottom of the
label stack. label stack.
The GAL MUST only be used where both these purposes apply. The GAL MUST only be used where both these purposes apply.
4.1. Relationship with Existing MPLS OAM Alert Mechanisms 4.1. Relationship with Existing MPLS OAM Alert Mechanisms
RFC 4379 [13] and BFD-MPLS [12] define alert mechanisms that enable RFC 4379 [13] and BFD-MPLS [12] define alert mechanisms that enable
an MPLS LSR to identify and process MPLS OAM packets when these are an MPLS LSR to identify and process MPLS OAM packets when these are
encapsulated in an IP header. These alert mechanisms are based, for encapsulated in an IP header. These alert mechanisms are based, for
example, on Time To Live (TTL) expiration and/or on the use of an IP example, on Time To Live (TTL) expiration and/or on the use of an IP
destination address in the range of 127/8 or 0:0:0:0:0:FFFF: destination address in the range of 127.0.0.0/8 or 0:0:0:0:0:FFFF:
127.0.0.0/104, respectively for IPv4 and IPv6. 127.0.0.0/104, respectively for IPv4 and IPv6.
These mechanisms are the default mechanisms for identifying MPLS OAM These mechanisms are the default mechanisms for identifying MPLS OAM
packets when encapsulated in an IP header although the mechanism packets when encapsulated in an IP header although the mechanism
defined in this document MAY also be used. defined in this document MAY also be used.
4.2. GAL Applicability and Usage 4.2. GAL Applicability and Usage
In MPLS-TP, the GAL MUST be used with packets on a G-ACh on LSPs, In MPLS-TP, the GAL MUST be used with packets on a G-ACh on LSPs,
Concatenated Segments of LSPs, and with Sections, and MUST NOT be Concatenated Segments of LSPs, and with Sections, and MUST NOT be
used with PWs. It MUST always be at the bottom of the label stack used with PWs. It MUST always be at the bottom of the label stack
(i.e., S bit set to 1). However, in other MPLS environments, this (i.e., S bit set to 1). However, in other MPLS environments, this
document places no restrictions on where the GAL may appear within document places no restrictions on where the GAL may appear within
the label stack or its use with PWs. Where the GAL is at the bottom the label stack or its use with PWs. Where the GAL is at the bottom
of the label stack (i.e. S bit set to 1) then it MUST always be of the label stack (i.e., S bit set to 1) then it MUST always be
followed by an ACH. followed by an ACH.
The GAL MUST NOT appear in the label stack when transporting normal The GAL MUST NOT appear in the label stack when transporting normal
user-plane packets. Furthermore, when present, the GAL MUST NOT user-plane packets. Furthermore, when present, the GAL MUST NOT
appear more than once in the label stack. appear more than once in the label stack.
A receiving LSR, LER or PE MUST NOT forward a G-ACh packet to another A receiving LSR, LER or PE MUST NOT forward a G-ACh packet to another
node based on the GAL label. node based on the GAL label.
4.2.1. GAL Processing 4.2.1. GAL Processing
skipping to change at page 11, line 45 skipping to change at page 10, line 45
LSRs (B and C) for a given LSP which is established from A to D and LSRs (B and C) for a given LSP which is established from A to D and
switched in B and C. switched in B and C.
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+
| A |-------------| B |-------------| C |-------------| D | | A |-------------| B |-------------| C |-------------| D |
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+
Figure 5: Maintenance over a LSP Figure 5: Maintenance over a LSP
In this example, a G-ACh exists on the LSP that extends between LERs In this example, a G-ACh exists on the LSP that extends between LERs
A and D, via LSRs B and C. Only A and D may initiate the generation A and D, via LSRs B and C. Only A and D may initiate new G-ACh
of G-ACh packets. A, B, C and D may also originate and process G-ACh packets. A, B, C and D may process and respond to G-ACh packets.
packets.
The following figure (Figure 6) depicts the format of a MPLS-TP G-ACh The following figure (Figure 6) depicts the format of an MPLS-TP
packet when used for an LSP. G-ACh packet when used for an LSP.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSP Label | TC |S| TTL | | LSP Label | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GAL | TC |S| TTL | | GAL | TC |S| TTL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ACH | | ACH |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 12, line 31 skipping to change at page 11, line 31
~ G-ACh Message ~ ~ G-ACh Message ~
~ | ~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: G-ACh packet format for a LSP Figure 6: G-ACh packet format for a LSP
Note that it is possible that the LSP may be tunneled in another LSP Note that it is possible that the LSP may be tunneled in another LSP
(e.g., if a MPLS Tunnel exists between B and C), and as such other (e.g., if a MPLS Tunnel exists between B and C), and as such other
LSEs may be present in the label stack. LSEs may be present in the label stack.
To send a maintenance message on the LSP associated control channel, To send a G-ACh message on the LSP associated control channel, the
the LER (A) generates a G-ACh message, to which it MAY prepend an ACH LER (A) generates a G-ACh message, to which it MAY prepend an ACH TLV
TLV Header and appropriate ACH TLVs, adds an ACH to which it, pushes Header and appropriate ACH TLVs. It then adds an ACH, onto which it
a GAL LSE and finally the LSP Label LSE. pushes a GAL LSE. Finally, the LSP Label LSE is pushed onto the
resulting packet.
o The TTL field of the GAL LSE MUST be set to at least 1. The exact o The TTL field of the GAL LSE MUST be set to at least 1. The exact
value of the TTL is application specific. See Section 4.2.1 for value of the TTL is application specific. See Section 4.2.1 for
definition and processing rules. definition and processing rules.
o The S bit of the GAL MUST be set according to its position in the o The S bit of the GAL MUST be set according to its position in the
label stack (see Section 4.2). label stack (see Section 4.2).
o The setting of the TC field of the GAL is application specific. o The setting of the TC field of the GAL is application specific.
See Section 4.2.1 for definition and processing rules. See Section 4.2.1 for definition and processing rules.
The G-ACh message, the ACH or the GAL SHOULD NOT be modified towards LSRs MUST NOT modify the G-ACh message, the ACH or the GAL towards
the targeted destination. Upon reception of the labeled packet, the the targeted destination.
targeted destination, after having checked both the LSP Label and GAL
LSEs fields, SHOULD pass the whole packet to the appropriate Note: This is because once a G-ACh packet has been sent on an LSP,
processing entity. no node has visibility of it unless the LSP label TTL expires or
the GAL is exposed when the LSP label is popped. If this is at
the targeted destination, for example indicated by an address in
an ACH TLV, then processing can proceed as specified below. If
this is not the targeted destination, but the node has agreed to
process packets on that ACH channel, then the processing applied
to the packet is out of scope of this docuemnt. However, the ACH
type MUST be maintained if the packet is forwarded unmodified to
another node.
Upon reception of the labeled packet, the targeted destination, after
having checked both the LSP Label and GAL LSEs fields, SHOULD pass
the whole packet to the appropriate processing entity.
4.2.1.2. MPLS Section 4.2.1.2. MPLS Section
The following figure (Figure 7) depicts an example of an MPLS The following figure (Figure 7) depicts an example of an MPLS
Section. Section.
+---+ +---+ +---+ +---+
| A |-------------| Z | | A |-------------| Z |
+---+ +---+ +---+ +---+
skipping to change at page 13, line 49 skipping to change at page 13, line 28
| ~ | ~
~ G-ACh message ~ ~ G-ACh message ~
~ | ~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: G-ACh packet format for an MPLS Section Figure 8: G-ACh packet format for an MPLS Section
To send a G-ACh message on a control channel associated to the To send a G-ACh message on a control channel associated to the
Section, the head-end LSR (A) of the Section generates a G-ACh Section, the head-end LSR (A) of the Section generates a G-ACh
message, to which it MAY prepend an ACH TLV Header and appropriate message, to which it MAY prepend an ACH TLV Header and appropriate
ACH TLVs, adds an ACH to which it pushes a GAL LSE. ACH TLVs. Next the LSR adds an ACH. Finally it pushes a GAL LSE.
o The TTL field of the GAL MUST be set to at least 1. The exact o The TTL field of the GAL MUST be set to at least 1. The exact
value of the TTL is application specific. See Section 4.2.1 for value of the TTL is application specific. See Section 4.2.1 for
definition and processing rules. definition and processing rules.
o The S bit of the GAL MUST be set according to its position in the o The S bit of the GAL MUST be set according to its position in the
label stack. (see Section 4.2). label stack. (see Section 4.2).
o The setting of the TC field of the GAL is application specific. o The setting of the TC field of the GAL is application specific.
See Section 4.2.1 for definition and processing rules. See Section 4.2.1 for definition and processing rules.
The G-ACh message, the ACH and the GAL SHOULD NOT be modified towards Intermediate nodes of the MPLSsection MUST NOT modify the G-ACh
the tail-end LSR (Z). Upon reception of the G-ACh packet, the tail- message, the ACH and the GAL towards the tail-end LSR (Z). Upon
end LSR (Z), after having checked the GAL LSE fields, SHOULD pass the reception of the G-ACh packet, the tail-end LSR (Z), after having
whole packet to the appropriate processing entity. checked the GAL LSE fields, SHOULD pass the whole packet to the
appropriate processing entity.
4.3. Relationship with RFC 3429 4.3. Relationship with RFC 3429
RFC 3429 [18] describes the assignment of one of the reserved label RFC 3429 [18] describes the assignment of one of the reserved label
values, defined in RFC 3032 [5], to the 'OAM Alert Label' that is values, defined in RFC 3032 [5], to the 'OAM Alert Label' that is
used by user-plane MPLS OAM functions for the identification of MPLS used by user-plane MPLS OAM functions for the identification of MPLS
OAM packets. The value of 14 is used for that purpose. OAM packets. The value of 14 is used for that purpose.
Both this document and RFC 3429 [18] therefore describe the Both this document and RFC 3429 [18] therefore describe the
assignment of reserved label values for similar purposes. The assignment of reserved label values for similar purposes. The
skipping to change at page 15, line 21 skipping to change at page 14, line 47
o It has not, through means outside the scope of this document, o It has not, through means outside the scope of this document,
indicated to the sending LSR, LER or PE that it will process indicated to the sending LSR, LER or PE that it will process
associated channel packets on the Channel Type indicated by the associated channel packets on the Channel Type indicated by the
ACH of the received packet. ACH of the received packet.
o The packet is received on an Experimental Channel Type that is o The packet is received on an Experimental Channel Type that is
locally disabled. locally disabled.
o If the ACH was indicated by the presence of a GAL, and the first o If the ACH was indicated by the presence of a GAL, and the first
nibble of the ACH of the received packet is not 0b0001. nibble of the ACH of the received packet is not 0001b.
o The ACH version is not recognized. o The ACH version is not recognized.
In addition, it MAY increment an error counter and MAY also issue a In addition, the LER, LSR or PE MAY increment an error counter and
system and/or SNMP notification. MAY also issue a system and/or SNMP notification.
6. Congestion Considerations 6. Congestion Considerations
The congestion considerations detailed in RFC 5085 [2] apply. The congestion considerations detailed in RFC 5085 [1] apply.
7. Security Considerations 7. Contributing Authors
The editors gratefully acknowledge the contributions of Sami Boutros,
Italo Busi, Marc Lasserre, Lieven Levrau and Siva Sivabalan
8. Acknowledgments
The authors would like to thank Malcolm Betts, ITU-T Study Group 15,
and all members of the teams (the Joint Working Team, the MPLS
Interoperability Design Team in IETF and the MPLS-TP Ad-Hoc Team in
ITU-T) involved in the definition and specification of the MPLS
Transport Profile.
9. Security Considerations
The security considerations for the associated control channel are The security considerations for the associated control channel are
described in RFC 4385 [3]. Further security considerations MUST be described in RFC 4385 [2]. Further security considerations MUST be
described in the relevant associated channel type specification. described in the relevant associated channel type specification.
RFC 5085 [2] provides data plane related security considerations. RFC 5085 [1] provides data plane related security considerations.
These also apply to a G-ACh, whether the alert mechanism uses a GAL These also apply to a G-ACh, whether the alert mechanism uses a GAL
or only an ACH. or only an ACH.
8. IANA Considerations 10. IANA Considerations
This document requests that IANA allocates a label value, to the GAL, This document requests that IANA allocates a label value, to the GAL,
from the pool of reserved labels in the "Multiprotocol Label from the pool of reserved labels in the "Multiprotocol Label
Switching Architecture (MPLS) Label Values" registry, and suggests Switching Architecture (MPLS) Label Values" registry, and suggests
this value to be 13. this value to be 13.
Note to RFC Editor: The above text "and suggests this value to be
13" needs to be replaced with "with a value of 13." when the RFC
is published and IANA has allocated the value.
Channel Types for the Associated Channel Header are allocated from Channel Types for the Associated Channel Header are allocated from
the IANA "PW Associated Channel Type" registry [4]. The PW the IANA "PW Associated Channel Type" registry [4]. The PW
Associated Channel Type registry is currently allocated based on the Associated Channel Type registry is currently allocated based on the
IETF consensus process, described in [9]. This allocation process IETF consensus process (termed "IETF Review" in [9]). This
was chosen based on the consensus reached in the PWE3 working group allocation process was chosen based on the consensus reached in the
that pseudowire associated channel mechanisms should be reviewed by PWE3 working group that pseudowire associated channel mechanisms
the IETF and only those that are consistent with the PWE3 should be reviewed by the IETF and only those that are consistent
architecture and requirements should be allocated a code point. with the PWE3 architecture and requirements should be allocated a
code point.
However, a requirement has emerged (see [15]) to allow for However, a requirement has emerged (see [15]) to allow for
optimizations or extensions to OAM and other control protocols optimizations or extensions to OAM and other control protocols
running in an associated channel to be experimented without resorting running in an associated channel to be experimented without resorting
to the IETF standards process, by supporting experimental code to the IETF standards process, by supporting experimental code
points. This would prevent code points used for such functions from points. This would prevent code points used for such functions from
being used from the range allocated through the IETF standards and being used from the range allocated through the IETF standards and
thus protects an installed base of equipment from potential thus protects an installed base of equipment from potential
inadvertent overloading of code points. In order to support this inadvertent overloading of code points. In order to support this
requirement, this document requests that the code point allocation requirement, this document requests that the code point allocation
skipping to change at page 17, line 6 skipping to change at page 17, line 6
Registry: Registry:
Value Description TLV Follows Reference Value Description TLV Follows Reference
----- ---------------------------- ----------- --------- ----- ---------------------------- ----------- ---------
0x21 ACH carries an IPv4 packet No [RFC4385] 0x21 ACH carries an IPv4 packet No [RFC4385]
0x57 ACH carries an IPv6 packet No [RFC4385] 0x57 ACH carries an IPv6 packet No [RFC4385]
Figure 9: PW Channel Type registry Figure 9: PW Channel Type registry
IANA is requested create a new registry called the Associated Channel IANA is requested create a new registry called the Associated Channel
Header TLV Registry. The allocation policy for this registry is IETF Header TLV Registry. The allocation policy for this registry is IETF
consensus. This registry MUST record the following information. review. This registry MUST record the following information. There
There are no initial entries. are no initial entries.
Name Type Length Description Reference Name Type Length Description Reference
(octets) (octets)
Figure 10: ACH TLV registry Figure 10: ACH TLV registry
9. Acknowledgments 11. References
The authors would like to thank Malcolm Betts, ITU-T Study Group 15,
and all members of the teams (the Joint Working Team, the MPLS
Interoperability Design Team in IETF and the MPLS-TP Ad-Hoc Team in
ITU-T) involved in the definition and specification of the MPLS
Transport Profile.
10. References
10.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement 11.1. Normative References
Levels", BCP 14, RFC 2119, March 1997.
[2] Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit [1] Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit
Connectivity Verification (VCCV): A Control Channel for Connectivity Verification (VCCV): A Control Channel for
Pseudowires", RFC 5085, December 2007. Pseudowires", RFC 5085, December 2007.
[3] Bryant, S., Swallow, G., Martini, L., and D. McPherson, [2] Bryant, S., Swallow, G., Martini, L., and D. McPherson,
"Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for Use "Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for Use
over an MPLS PSN", RFC 4385, February 2006. over an MPLS PSN", RFC 4385, February 2006.
[3] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[4] Martini, L., "IANA Allocations for Pseudowire Edge to Edge [4] Martini, L., "IANA Allocations for Pseudowire Edge to Edge
Emulation (PWE3)", BCP 116, RFC 4446, April 2006. Emulation (PWE3)", BCP 116, RFC 4446, April 2006.
[5] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., Farinacci, [5] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., Farinacci,
D., Li, T., and A. Conta, "MPLS Label Stack Encoding", D., Li, T., and A. Conta, "MPLS Label Stack Encoding",
RFC 3032, January 2001. RFC 3032, January 2001.
[6] Andersson, L. and R. Asati, "Multiprotocol Label Switching [6] Andersson, L. and R. Asati, "Multiprotocol Label Switching
(MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic (MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic
Class" Field", RFC 5462, February 2009. Class" Field", RFC 5462, February 2009.
skipping to change at page 18, line 15 skipping to change at page 18, line 6
[8] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol Label [8] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol Label
Switching Architecture", RFC 3031, January 2001. Switching Architecture", RFC 3031, January 2001.
[9] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA [9] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. Considerations Section in RFCs", BCP 26, RFC 5226, May 2008.
[10] Narten, T., "Assigning Experimental and Testing Numbers [10] Narten, T., "Assigning Experimental and Testing Numbers
Considered Useful", BCP 82, RFC 3692, January 2004. Considered Useful", BCP 82, RFC 3692, January 2004.
10.2. Informative References 11.2. Informative References
[11] Bocci, M., Bryant, S., and L. Levrau, "A Framework for MPLS in [11] Bocci, M., Bryant, S., and L. Levrau, "A Framework for MPLS in
Transport Networks", draft-ietf-mpls-tp-framework-00 (work in Transport Networks", draft-ietf-mpls-tp-framework-00 (work in
progress), November 2008. progress), November 2008.
[12] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow, "BFD [12] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow, "BFD
For MPLS LSPs", draft-ietf-bfd-mpls-07 (work in progress), For MPLS LSPs", draft-ietf-bfd-mpls-07 (work in progress),
June 2008. June 2008.
[13] Kompella, K. and G. Swallow, "Detecting Multi-Protocol Label [13] Kompella, K. and G. Swallow, "Detecting Multi-Protocol Label
Switched (MPLS) Data Plane Failures", RFC 4379, February 2006. Switched (MPLS) Data Plane Failures", RFC 4379, February 2006.
[14] Nadeau, T. and C. Pignataro, "Bidirectional Forwarding [14] Nadeau, T. and C. Pignataro, "Bidirectional Forwarding
Detection (BFD) for the Pseudowire Virtual Circuit Detection (BFD) for the Pseudowire Virtual Circuit
Connectivity Verification (VCCV)", draft-ietf-pwe3-vccv-bfd-03 Connectivity Verification (VCCV)", draft-ietf-pwe3-vccv-bfd-04
(work in progress), February 2009. (work in progress), May 2009.
[15] Vigoureux, M., Ward, D., and M. Betts, "Requirements for OAM in [15] Vigoureux, M., Ward, D., and M. Betts, "Requirements for OAM in
MPLS Transport Networks", MPLS Transport Networks",
draft-ietf-mpls-tp-oam-requirements-01 (work in progress), draft-ietf-mpls-tp-oam-requirements-01 (work in progress),
March 2009. March 2009.
[16] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N., and [16] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N., and
S. Ueno, "MPLS-TP Requirements", S. Ueno, "MPLS-TP Requirements",
draft-ietf-mpls-tp-requirements-06 (work in progress), draft-ietf-mpls-tp-requirements-06 (work in progress),
April 2009. April 2009.
 End of changes. 53 change blocks. 
113 lines changed or deleted 132 lines changed or added

This html diff was produced by rfcdiff 1.35. The latest version is available from http://tools.ietf.org/tools/rfcdiff/