Network Working Group J. Dong
Internet-Draft M. Chen
Intended status: Standards Track Huawei Technologies
Expires: April 25, 2013 Z. Li
China Mobile
October 22, 2012
RSVP-TE Extensions for Lock Instruct and Loopback in MPLS Transport
Profile
draft-dong-ccamp-rsvp-te-mpls-tp-li-lb-04
Abstract
This document specifies extensions to RSVP-TE to support lock
instruct and loopback mechanism for MPLS-TP LSPs. The mechanisms are
intended to be applicable to other technologies which use GMPLS/
RSVP-TE as control plane.
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].
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 25, 2013.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Extensions to RSVP-TE . . . . . . . . . . . . . . . . . . . . . 3
3. Operations . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Lock Instruct . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Loopback . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.1. Normative References . . . . . . . . . . . . . . . . . . . 6
7.2. Informative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7
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1. Introduction
The requirements for Lock Instruct (LI) and Loopback (LB) are
specified in [RFC5860], and the framework of LI and LB is specified
in [RFC6371]. [RFC6435] defines management plane based Lock Instruct
(LI) and Loopback (LB) mechanisms, and an LI OAM message can be used
for additional lock coordination between the MEPs. Management plane
based LI and LB is suitable for scenarios where dynamic control plane
is not available.
When a control plane is used for establishing MPLS-TP LSPs, it is
natural to use and extend the control plane protocol to implement LI
and LB functions. Since LI and LB would modify the forwarding plane
of an LSP, without the involvement of control plane this may result
in inconsistency of the LSP information between control plane and
data plane. Besides, with control plane mechanisms, it does not need
to rely on the TTL expiration to make the OAM requests reach
particular MIP or MEP.
There are some existing control plane based OAM provisioning
mechanisms for MPLS-TP. For example,
[I-D.ietf-ccamp-rsvp-te-mpls-tp-oam-ext] specifies the RSVP-TE
extensions for the configuration of proactive OAM functions for
MPLS-TP LSPs when control plane is used.
This document specifies extensions to RSVP-TE to implement LI and LB
functions for MPLS-TP LSPs when MPLS-TP control plane is used. The
mechanisms defined in this document are complementary to [RFC6435].
2. Extensions to RSVP-TE
The A (Administratively down) bit in ADMIN_STATUS object [RFC3471]
[RFC3473] is used to indicate the lock/unlock of the LSP. Format of
ADMIN_STATUS Object is as below:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | Class-Num(196)| C-Type (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R| Reserved |H|L|I|C|T|A|D|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Reflect (R): 1 bit - see [RFC3471]
Handover (H): 1 bit - see [RFC5852]
Lockout (L): 1 bit - see [RFC4872]
Inhibit Alarm Indication (I): 1 bit - see [RFC4783]
Call Control (C): 1 bit - see [RFC4974]
Testing (T): 1 bit - see [RFC3471]
Administratively down (A): 1 bit - see [RFC3471], reused for Lock
Deletion in progress (D): 1 bit - see [RFC3471]
A new bit is defined in Attribute Flags TLV [RFC5420] to indicate the
loopback mode. The bit number is TBA.
Bit Number Name and Usage
TBA Loopback mode desired.
This flag indicates a particular node on the LSP is required
to enter loopback mode.
This MAY also be used for specifying the loopback state
of the node.
3. Operations
3.1. Lock Instruct
When a MEP wants to put an LSP into lock mode, it MUST send a Path
message with the Administratively down (A) bit and the Reflect (R)
bit in ADMIN_STATUS Object set. The intermediate nodes SHOULD
forward the message with the A bit unchanged to the downstream .
On receipt of this Path message, the receiving MEP node SHOULD try to
take the LSP out of service. If the receiving MEP locks the LSP
successfully, it SHOULD send a Resv message with the A bit in
ADMIN_STATUS object set. Otherwise, it SHOULD send a PathErr message
with the Error Code "OAM Problem" and the new Error Value "Lock
Failure", and the following Resv message SHOULD be sent with the A
bit cleared. During this procedure, the intermediate nodes would be
aware of whether the LSP is in Lock mode or not.
When an LSP is put in lock mode, the subsequent Path and Resv
messages SHOULD keep the A bit in ADMIN_STATUS Object set.
When a MEP wants to take the LSP out of the lock mode, it MUST send a
Path message with the A bit in ADMIN_STATUS Object cleared. The
intermediate nodes SHOULD forward this message with the A bit
unchanged to the downstream.
On receipt of this Path message, the receiving MEP node SHOULD try to
bring the LSP back to service. If the receiving MEP unlocks the LSP
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successfully, it SHOULD send a Resv message with the A bit in
ADMIN_STATUS Object cleared. Otherwise, it SHOULD send a PathErr
message with the Error Code "OAM Problem" and the new Error Value
"Unlock Failure", and the following Resv message SHOULD be sent with
the A bit set.
When an LSP is taken out of lock mode, the subsequent Path and Resv
messages SHOULD keep the A bit in ADMIN_STATUS Object cleared.
3.2. Loopback
The loopback request can be sent either to the remote MEP or to a
particular MIP node. The mechanism defined in
[I-D.margaria-ccamp-lsp-attribute-ero] is used for addressing the
loopback request to a particular node on the LSP. The loopback
request is acceptable only when the LSP is in lock mode.
When a MEP wants to put a particular LSR on the LSP into loopback
mode, it MUST send a Path message with the Loopback bit in the
Attribute Flags TLV set. The mechansim defined in
[I-D.margaria-ccamp-lsp-attribute-ero] is used to address the
loopback request to the particular LSR. The Administratively down
(A) bit in ADMIN_STATUS object SHOLUD be set to keep the LSP in lock
mode.
On receipt of this Path message, the target LSR of the loopback
request SHOULD try to put the LSP into loopback mode. If the node
puts the LSP into loopback mode successfully, it SHOULD set the the
Loopback (B) Bit in the RRO Attribute subobject [RFC5420] and push
this subobject onto the RRO object in the corresponding Resv message.
The Administratively down (A) bit in ADMIN_STATUS object SHOULD be
set in the Resv message. If the node cannot put the LSP into
loopback mode, it SHOULD send a PathErr message with the Error Code
"OAM Problem" and the new Error Value "Loopback Failure".
When a MEP wants to take the LSP out of loopback mode, it MUST send a
Path message with the Loopback bit in the Attribute Flags TLV
cleared. The mechansim defined in
[I-D.margaria-ccamp-lsp-attribute-ero] is used to indicate that the
particular LSR SHOULD exit loopback mode for this LSP. The
Administratively down (A) bit in ADMIN_STATUS object SHOULD be set.
On receipt of this Path message, the target node SHOULD try to take
the LSP out of loopback mode. If the node takes the LSP out of
loopback mode successfully, it SHOULD clear the the Loopback (B) Bit
in the RRO Attribute subobject and push this subobject onto the RRO
object in the corresponding Resv message. The Administratively down
(A) Bit in ADMIN_STATUS Object SHOULD be set. Otherwise, the node
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SHOULD send a PathErr message with the Error Code "OAM Problem" and
the new Error Value "Exit Loopback Failure".
4. IANA Considerations
One bit number Loopback needs to be assigned in the Attribute Flags
registry.
Four new Error Values need to be allocated for Error Code "OAM
Problem": "Lock Failure", "Unlock Failure", "Loopback Failure", "Exit
Loopback Failure".
5. Security Considerations
This document does not introduce any new security issues above those
identified in [RFC3209] and [RFC3473].
6. Acknowledgements
The authors would like to thank Greg Mirsky, Lou Berger and Francesco
Fondelli for their comments and suggestions.
7. References
7.1. Normative References
[I-D.ietf-ccamp-oam-configuration-fwk]
Takacs, A., Fedyk, D., and H. Jia, "GMPLS RSVP-TE
extensions for OAM Configuration",
draft-ietf-ccamp-oam-configuration-fwk-08 (work in
progress), July 2012.
[I-D.margaria-ccamp-lsp-attribute-ero]
Margaria, C., Schroetter, D., Martinelli, G., Balls, S.,
and B. Wright, "LSP Attribute in ERO",
draft-margaria-ccamp-lsp-attribute-ero-01 (work in
progress), July 2012.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[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.
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[RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Functional Description", RFC 3471,
January 2003.
[RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Resource ReserVation Protocol-Traffic
Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.
[RFC3945] Mannie, E., "Generalized Multi-Protocol Label Switching
(GMPLS) Architecture", RFC 3945, October 2004.
[RFC5420] Farrel, A., Papadimitriou, D., Vasseur, JP., and A.
Ayyangarps, "Encoding of Attributes for MPLS LSP
Establishment Using Resource Reservation Protocol Traffic
Engineering (RSVP-TE)", RFC 5420, February 2009.
[RFC5860] Vigoureux, M., Ward, D., and M. Betts, "Requirements for
Operations, Administration, and Maintenance (OAM) in MPLS
Transport Networks", RFC 5860, May 2010.
[RFC6371] Busi, I. and D. Allan, "Operations, Administration, and
Maintenance Framework for MPLS-Based Transport Networks",
RFC 6371, September 2011.
7.2. Informative References
[I-D.ietf-ccamp-rsvp-te-mpls-tp-oam-ext]
Bellagamba, E., Andersson, L., Skoldstrom, P., Ward, D.,
and A. Takacs, "Configuration of Pro-Active Operations,
Administration, and Maintenance (OAM) Functions for MPLS-
based Transport Networks using RSVP-TE",
draft-ietf-ccamp-rsvp-te-mpls-tp-oam-ext-10 (work in
progress), October 2012.
[RFC6435] Boutros, S., Sivabalan, S., Aggarwal, R., Vigoureux, M.,
and X. Dai, "MPLS Transport Profile Lock Instruct and
Loopback Functions", RFC 6435, November 2011.
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Authors' Addresses
Jie Dong
Huawei Technologies
Huawei Building, No.156 Beiqing Rd.
Beijing 100095
China
Email: jie.dong@huawei.com
Mach Chen
Huawei Technologies
Huawei Building, No.156 Beiqing Rd.
Beijing 100095
China
Email: mach.chen@huawei.com
Zhenqiang Li
China Mobile
Unit2, Dacheng Plaza, No. 28 Xuanwumenxi Ave.
Beijing 100053
China
Email: lizhenqiang@chinamobile.com
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