Network Working Group N. Bahadur, Ed.
Internet-Draft R. Aggarwal, Ed.
Intended status: Standards Track D. Ward, Ed.
Expires: February 23, 2011 Juniper Networks, Inc.
T. Nadeau
BT
N. Sprecher
Y. Weingarten
Nokia Siemens Networks
August 22, 2010
LSP-Ping and BFD encapsulation over ACH
draft-ietf-mpls-tp-lsp-ping-bfd-procedures-01
Abstract
LSP-Ping and BFD for MPLS are existing and widely deployment OAM
mechanisms for MPLS LSPs. This document describes an ACH
encapsulation for LSP-Ping, that would enable use of LSP-Ping for
networks where IP addressing is not in use. This document also
clarifies the use of BFD for MPLS LSPs using ACH encapsulation, when
IP addressing may not be available and/or it may not be desirable to
encapsulate BFD packets in IP.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
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time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
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This Internet-Draft will expire on February 23, 2011.
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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
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the Trust Legal Provisions and are provided without warranty as
described in the BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Conventions used in this document . . . . . . . . . . . . . 3
1.2. LSP-Ping and BFD over ACH . . . . . . . . . . . . . . . . . 3
2. LSP-Ping extensions . . . . . . . . . . . . . . . . . . . . . . 3
2.1. LSP-Ping packet over ACH for LSPs . . . . . . . . . . . . . 3
2.2. LSP-Ping packet over ACH for PWs . . . . . . . . . . . . . 4
2.3. Source Address TLV . . . . . . . . . . . . . . . . . . . . 4
2.4. MEP and MIP Identifier . . . . . . . . . . . . . . . . . . 5
3. Running BFD over MPLS-TP LSPs . . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
5.1. New ACH Channel Types . . . . . . . . . . . . . . . . . . . 7
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6.1. Normative References . . . . . . . . . . . . . . . . . . . 7
6.2. Informative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
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1. Introduction
LSP-Ping [RFC4379] and BFD for MPLS [RFC5884] are OAM mechanisms for
MPLS LSPs. This document describes an ACH encapsulation for LSP-Ping
for networks that do not use IP addressing. When IP addressing is in
use, the LSP-Ping procedures specified in [RFC4379] apply as is.
This document also clarifies the use of BFD for MPLS LSPs using ACH
encapsulation [RFC5586], when IP addressing may not be available
and/or it may not be desirable to encapsulate BFD packets in IP.
1.1. Conventions used in this document
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].
1.2. LSP-Ping and BFD over ACH
In certain MPLS-TP deployment scenarios IP addressing might not be
available or it may be preferred to use non-IP encapsulation for LSP-
Ping and BFD packets. The remainder of this document defines
extensions to LSP-Ping and procedures for using BFD, for such
scenarios.
Section 2.1 and Section 2.2 describe a new ACH code-point for
performing LSP-Ping over ACH. Section 3 describes procedures for
using BFD over ACH.
2. LSP-Ping extensions
2.1. LSP-Ping packet over ACH for LSPs
[RFC5586] defines an ACH mechanism for MPLS LSPs. This document
defines a new ACH channel type for LSP-Ping, when IP addressing is
not in use, for LSP-Ping over associated bi-directional LSPs and co-
routed bi-directional LSPs. ACH TLVs MAY be associated with this
channel type.
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 2
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 1|Version| Reserved | LSP-Ping Channel Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: LSP-Ping ACH Channel Type
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When ACH header is used, an LSP-Ping packet will look as follows:
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 2
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MPLS Label stack |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GAL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 1|Version| Reserved | LSP-Ping Channel Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ACH TLV Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ACH TLVs |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSP-Ping payload |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: LSP-Ping packet with ACH
When using LSP-Ping over the ACH header, the LSP-Ping Reply mode
[RFC4379] in the LSP-Ping echo request MUST be set to 4 (Reply via
application level control channel).
2.2. LSP-Ping packet over ACH for PWs
[RFC4385] defines an PW-ACH mechanism for pseudowires. The ACH
channel type for LSP-Ping defined in Section 2.1 will be re-used for
pseudowires so that IP addressing is not needed when using LSP-Ping
OAM over pseudowires.
2.3. Source Address TLV
When sending LSP-Ping packets using ACH, without IP encapsulation,
there MAY be a need to identify the source address of the packet.
This source address will be specified via the Source Address TLV,
being defined in [I-D.ietf-mpls-tp-ach-tlv]. No more than 1 source
address TLV MAY be present in a LSP-Ping packet. The source address
MUST specify the address of the originator of the packet. If more
than 1 such TLV is present in a LSP-Ping request packet, then an
error code of 1 (Malformed echo request received), [ Section 3.1
[RFC4379]], SHOULD be returned. If more than 1 source address TLV is
present, then the packet SHOULD be dropped without further
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processing.
2.4. MEP and MIP Identifier
When sending LSP-Ping packets using ACH, there MAY be a need to
identify the maintenance end point (MEP) and/or the maintenance
intermediate point (MIP) being monitored
[I-D.ietf-mpls-tp-rosetta-stone]. The MEP/MIP identifiers defined in
[I-D.ietf-mpls-tp-identifiers] MAY be carried in the ACH TLVs
[I-D.ietf-mpls-tp-ach-tlv] for identification.
3. Running BFD over MPLS-TP LSPs
[RFC5884] describes how BFD can be used for Continuity Check of MPLS
LSPs. The procedures described in [RFC5884] MUST be used when IP
encapsulation is in use. This section clarifies the usage of BFD in
the context of MPLS-TP LSPs when it is not desirable to use IP
encapsulation. When using BFD over MPLS-TP LSPs, the BFD
discriminator MUST either be signaled via LSP-Ping or be statically
configured. The BFD packets MUST be sent over ACH when IP
encapsulation is not used.
This document defines a new ACH channel type for BFD over G-ACH, when
IP addressing is not in use, for running BFD over associated bi-
directional LSPs and co-routed bi-directional LSPs. ACH TLVs MAY be
associated with this channel type.
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 2
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 1|Version| Reserved | BFD over G-ACH Channel Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: BFD over G-ACH Channel Type
BFD packets, for both directions, MUST be sent over the MPLS-TP LSP
and IP forwarding SHOULD NOT be used for the reverse path. The
format of a BFD packet when using it as an OAM tool for MPLS-TP LSPs
SHOULD be as follows:
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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 2
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MPLS Label stack |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GAL |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 1|Version| Reserved | BFD over G-ACH Channel Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ACH TLV Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ACH TLVs |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BFD payload |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: BFD packet over MPLS-TP LSPs
[RFC5885] specifies how BFD can be used over MPLS PWs. One MAY use
BFD over G-ACH channel type to run BFD over PWs if ACH TLV support is
needed.
BFD supports continuous fault monitoring and thus meets the pro-
active Continuity Check and verification requirement specified in
[RFC5860]. BFD SHOULD be run pro-actively. This function SHOULD be
performed between End Points (MEPs) of PWs, LSPs and Sections. For
point to multipoint Continuity Check, there is work in progress on
using BFD for P2MP MPLS LSPs ( [I-D.katz-ward-bfd-multipoint]) and
this can be leveraged for MPLS-TP LSPs as well. Failure of a BFD
session over a LSP can be used to trigger protection switching or
other fault remedial procedures.
When sending BFD packets using ACH, there MAY be a need to identify
the maintenance end point (MEP) being monitored. The MEP identifier
defined in [I-D.ietf-mpls-tp-identifiers] can be carried in the ACH
TLVs [I-D.ietf-mpls-tp-ach-tlv] for identification.
4. Security Considerations
The draft does not introduce any new security considerations. Those
discussed in [RFC4379] are also applicable to this document.
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5. IANA Considerations
5.1. New ACH Channel Types
New Channels type are defined in Section 2.1 and Section 3. IANA is
requested to assign new values from the "PW Associated Channel Type"
registry, as per IETF consensus policy.
Value Meaning
----- -------
TBD Associated Channel carries LSP-Ping packet
TBD Associated Channel carries BFD over G-ACH
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4379] Kompella, K. and G. Swallow, "Detecting Multi-Protocol
Label Switched (MPLS) Data Plane Failures", RFC 4379,
February 2006.
[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.
6.2. Informative References
[I-D.ietf-mpls-tp-ach-tlv]
Boutros, S., Bryant, S., Sivabalan, S., Swallow, G., Ward,
D., and V. Manral, "Definition of ACH TLV Structure",
draft-ietf-mpls-tp-ach-tlv-02 (work in progress),
March 2010.
[I-D.ietf-mpls-tp-identifiers]
Bocci, M. and G. Swallow, "MPLS-TP Identifiers",
draft-ietf-mpls-tp-identifiers-02 (work in progress),
July 2010.
[I-D.ietf-mpls-tp-rosetta-stone]
Sprecher, N., "A Thesaurus for the Terminology used in
Multiprotocol Label Switching Transport Profile (MPLS-TP)
drafts/RFCs and ITU-T's Transport Network
Recommendations.", draft-ietf-mpls-tp-rosetta-stone-02
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(work in progress), May 2010.
[I-D.katz-ward-bfd-multipoint]
Katz, D. and D. Ward, "BFD for Multipoint Networks",
draft-katz-ward-bfd-multipoint-02 (work in progress),
February 2009.
[RFC5586] Bocci, M., Vigoureux, M., and S. Bryant, "MPLS Generic
Associated Channel", RFC 5586, June 2009.
[RFC5860] Vigoureux, M., Ward, D., and M. Betts, "Requirements for
Operations, Administration, and Maintenance (OAM) in MPLS
Transport Networks", RFC 5860, May 2010.
[RFC5884] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
"Bidirectional Forwarding Detection (BFD) for MPLS Label
Switched Paths (LSPs)", RFC 5884, June 2010.
[RFC5885] Nadeau, T. and C. Pignataro, "Bidirectional Forwarding
Detection (BFD) for the Pseudowire Virtual Circuit
Connectivity Verification (VCCV)", RFC 5885, June 2010.
Authors' Addresses
Nitin Bahadur (editor)
Juniper Networks, Inc.
1194 N. Mathilda Avenue
Sunnyvale, CA 94089
US
Phone: +1 408 745 2000
Email: nitinb@juniper.net
URI: www.juniper.net
Rahul Aggarwal (editor)
Juniper Networks, Inc.
1194 N. Mathilda Avenue
Sunnyvale, CA 94089
US
Phone: +1 408 745 2000
Email: rahul@juniper.net
URI: www.juniper.net
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David Ward (editor)
Juniper Networks, Inc.
1194 N. Mathilda Avenue
Sunnyvale, CA 94089
US
Phone: +1 408 745 2000
Fax:
Email: dward@juniper.net
URI: www.juniper.net
Thomas D. Nadeau
BT
BT Centre
81 Newgate Street
London EC1A 7AJ
United Kingdom
Email: tom.nadeau@bt.com
Nurit Sprecher
Nokia Siemens Networks
3 Hanagar St. Neve Ne'eman B
Hod Hasharon 45241
Israel
Phone: +972-9-775 1229
Email: nurit.sprecher@nsn.com
Yaacov Weingarten
Nokia Siemens Networks
3 Hanagar St. Neve Ne'eman B
Hod Hasharon 45241
Israel
Phone: +972-9-775 1827
Email: yaacov.weingarten@nsn.com
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