Network Working Group N. Bahadur, Ed.
Internet-Draft R. Aggarwal, Ed.
Intended status: Standards Track D. Ward, Ed.
Expires: September 24, 2010 Juniper Networks, Inc.
T. Nadeau
BT
N. Sprecher
Y. Weingarten
Nokia Siemens Networks
March 23, 2010
LSP-Ping and BFD encapsulation over ACH
draft-ietf-mpls-tp-lsp-ping-bfd-procedures-00
Abstract
LSP-Ping and BFD for MPLS are existing and widely deployment OAM
mechanisms for MPLS LSPs. This document describes ACH encapsulation
for LSP-Ping, to enable use of LSP-Ping when 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.
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This Internet-Draft will expire on September 24, 2010.
Copyright Notice
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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
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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 . . . . . . . . . . . . . . . . . . 4
3. Running BFD over MPLS-TP LSPs . . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
5.1. New ACH Channel Type . . . . . . . . . . . . . . . . . . . 6
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6.1. Normative References . . . . . . . . . . . . . . . . . . . 6
6.2. Informative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
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1. Introduction
LSP-Ping [RFC4379] and [I-D.ietf-bfd-mpls] are OAM mechanisms for
MPLS LSPs. This document describes ACH encapsulation for LSP-Ping,
to enable use of LSP-Ping when IP addressing is not in use. When IP
addressing is in use, procedures specified in [RFC4379] apply as is.
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.
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. To enable re-use of OAM techniques provided by
LSP-Ping and BFD in such networks, rest of this document defines
extensions to LSP-Ping and procedures for using BFD.
Sections Section 2.1 and Section 2.2 describe a new ACH code-point
for performing LSP-Ping over ACH. Section 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.
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
When ACH header is used, an LSP-Ping packet will look 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 | LSP-Ping Channel Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 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]. Only 1 source address
TLV MUST 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 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
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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
[I-D.ietf-bfd-mpls] describes how BFD can be used for Continuity
Check for MPLS LSPs. The procedures described in [I-D.ietf-bfd-mpls]
MUST be used when IP addressing 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. The ACH Channel type MUST be set to the
value specified in [I-D.ietf-pwe3-vccv-bfd]. 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:
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 | Channel Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ACH TLVs |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BFD payload |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: BFD packet over MPLS-TP LSPs
[I-D.ietf-pwe3-vccv-bfd] specifies how BFD can be used over MPLS PWs.
BFD supports continuous fault monitoring and thus meets the pro-
active Continuity Check and verification requirement specified in
[I-D.ietf-mpls-tp-oam-requirements]. 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
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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) and/or the maintenance intermediate
point (MIP) being monitored. The MEP/MIP identifiers 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.
5. IANA Considerations
5.1. New ACH Channel Type
A new Channel type is defined in Section 2.1. IANA is requested to
assign a new value from the "PW Associated Channel Type" registry, as
per IETF consensus policy.
Value Meaning
----- -------
TBD Associated Channel carries LSP-Ping packet
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.
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6.2. Informative References
[I-D.ietf-bfd-mpls]
Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
"BFD For MPLS LSPs", draft-ietf-bfd-mpls-07 (work in
progress), June 2008.
[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-01 (work in progress),
March 2010.
[I-D.ietf-mpls-tp-oam-requirements]
Vigoureux, M. and D. Ward, "Requirements for OAM in MPLS
Transport Networks",
draft-ietf-mpls-tp-oam-requirements-06 (work in progress),
March 2010.
[I-D.ietf-mpls-tp-rosetta-stone]
Helvoort, H., Andersson, L., and N. Sprecher, "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-01 (work in progress),
October 2009.
[I-D.ietf-pwe3-vccv-bfd]
Nadeau, T. and C. Pignataro, "Bidirectional Forwarding
Detection (BFD) for the Pseudowire Virtual Circuit
Connectivity Verification (VCCV)",
draft-ietf-pwe3-vccv-bfd-07 (work in progress), July 2009.
[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.
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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
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.co
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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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