One document matched: draft-dong-pwe3-mpls-tp-li-lb-00.txt
Network Working Group J. Dong
Internet-Draft M. Chen
Intended status: Standards Track Huawei Technologies
Expires: September 2, 2012 G. Mirsky
Ericsson
March 1, 2012
LDP Extensions for Lock Instruct and Loopback of Pseudowire in MPLS
Transport Profile
draft-dong-pwe3-mpls-tp-li-lb-00
Abstract
This document specifies extensions to the Label Distribution Protocol
(LDP) to support provisioning of lock instruct and loopback mechanism
for MPLS-TP Pseudowires.
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
working documents as Internet-Drafts. The list of current Internet-
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Internet-Drafts are draft documents valid for a maximum of six months
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 September 2, 2012.
Copyright Notice
Copyright (c) 2012 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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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. LDP Extensions . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Extensions to MPLS-TP PW OAM Administration TLV . . . . . . 3
2.2. Extensions to PW Status TLV . . . . . . . . . . . . . . . . 4
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 of Lock Instruct (LI) and Loopback (LB) are
specified in [RFC5860], and the framework of LI and LB is specified
in [RFC6371]. [RFC6435] defines in-band Lock Instruct (LI) and
Loopback (LB) functions, which leverages the Generic Associated
Channel (GACH) and Generic Associated Channel Label (GAL) [RFC5586]
and the management plane to perform LI function and use the
management plane to perform LB function. In-band and Management
based LI and LB is suitable for scenarios where control plane is not
used.
When a dynamic control plane is used for establishing MPLS-TP PWs,
it's natural to use and extend the control plane protocol to
provision LI and LB functions. Unlike other OAM mechanisms, LI and
LB would modify the forwarding plane of a PW, thus without the
involvement of control plane this may result in inconsistency between
control plane and data plane. Besides, with control plane based
mechanism, it does not need to rely on the TTL expiration to make the
LI/LB requests to reach particular MIP or MEP.
This document specifies extensions to LDP to implement LI and LB for
MPLS-TP PWs when MPLS-TP control plane is used. The mechanisms
defined in this document are complementary to [RFC6435].
2. LDP Extensions
2.1. Extensions to MPLS-TP PW OAM Administration TLV
Two new flags (Lock bit and Loopback bit) are defined in MPLS-TP PW
OAM Administration TLV [I-D.ietf-pwe3-oam-config].
Format of extended MPLS-TP PW OAM Administration TLV 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Type (TBD) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|I|A|K|B| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Lock (K): When this bit is set, it indicates that the T-PE needs to
enable "Lock" function for this PW.
Loopback (B): When this bit is set, it indicates that the target node
of this message SHOULD enable loopback function for this PW.
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2.2. Extensions to PW Status TLV
Two new Status bits are defined in PW Status TLV:
Bit Mask Description
====================================================================
0x00000020 Pseudowire in Lock Mode [this document]
0x00000040 Pseudowire in Loopback Mode [this document]
3. Operations
The control plane based Lock Instruct and Loopback functions are
applicable to both Single-Segment Pseudowire (SS-PW) [RFC3985]
[RFC4447] and Multi-Segment Pseudowire (MS-PW) [RFC5659] [RFC6073].
3.1. Lock Instruct
When a PE/T-PE wants to put a PW in lock mode, it MUST send a Mapping
message with the Lock (K) bit in the MPLS-TP PW OAM Administration
TLV set.
For SS-PW, when the Mapping message arrives at the remote PE, the
receiving PE SHOULD try to take the PW out of service. If the
receiving PE locks the PW successfully, it SHOULD sent a Notification
message with PW status "Pseudowire in Lock Mode". Otherwise, it
SHOULD send a Notification message with the LDP Status code set to
"Lock Failure" , and the Status bit "Pseudowire in Lock Mode" MUST be
cleared.
For MS-PW, when the Mapping message arrives at a downstream S-PE, the
receiving S-PE SHOULD forward this Mapping message downstream towards
the remote T-PE. When the Mapping message arrives at the remote
T-PE, it SHOULD try to take the PW out of service. If the receiving
T-PE locks the PW successfully, it SHOULD send a Notification message
with PW status "Pseudowire in Lock Mode" to the upstream S-PE.
Otherwise, it SHOULD send a Notification message with the LDP Status
code set to "Lock Failure" , and the Status bit "Pseudowire in Lock
Mode" MUST be cleared. On receipt of the Notification message, the
S-PEs would know whether the MS-PW is locked successfully, and the
S-PEs SHOULD forward the Notification message back to the Source
T-PE.
When the PE/T-PE wants to take the PW out of the lock mode, it MUST
send a Mapping message with the Lock (K) bit in the MPLS-TP PW OAM
Administration TLV cleared. The receiving PE/T-PE SHOULD try to
unlock the PW. If the PW is unlocked successfully, the receiving PE/
T-PE SHOULD send a Notification message with PW status bit
"Pseudowire in Lock Mode" cleared. Otherwise, it SHOULD send a
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Notification message with the LDP Status code set to "Unlock
Failure", and the Status bit "Pseudowire in Lock Mode" MUST be set.
3.2. Loopback
When a PE/T-PE wants to put the remote PE/T-PE of a PW into loopback
mode, it MUST send a Mapping message with both the Lock (K) bit and
Loopback (B) bit in the MPLS-TP PW OAM Administration TLV set. When
a T-PE wants to put a particular S-PE of the PW into loopback mode,
it MUST send a Mapping message with both the Lock (K) bit and
Loopback (B) bit set, and a PW Switching Point PE TLV(SP-PE TLV)
[RFC6073] identifying the Target S-PE SHOULD be carried in the
Mapping message.
When the Mapping message arrives at the remote PE/T-PE, the receiving
PE SHOULD try to put the PW in loopback mode. If the receiver node
puts the PW into loopback mode successfully, it SHOULD send a
Notification message with PW status "Pseudowire in Loopback Mode".
Otherwise, it SHOULD send a Notification message with the LDP Status
code set to "Enter Loopback Failure" , and the Status bit "Pseudowire
in Loopback Mode" MUST be cleared.
When the Mapping message arrives at the targeted S-PE, the S-PE
SHOULD try to put the PW in loopback mode. If the S-PE puts the PW
into loopback mode successfully, it SHOULD send a Notification
message with PW status set to "Pseudowire in Loopback Mode". An
SP-PE TLV identifying the S-PE in loopback mode SHOULD also be
carried in the Notification message. If the S-PE fails to put the PW
into loopback mode, it SHOULD send a Notification message with the
LDP Status code set to "Enter Loopback Failure" , and the Status bit
"Pseudowire in Loopback Mode" MUST be cleared. An SP-PE TLV SHOULD
also be carried in the Notification message.
When the PE/T-PE wants to take the remote PE/T-PE out of the loopback
mode, it MUST send a Mapping message with the Lock (K) bit set and
Loopback (B) bit cleared. When the T-PE wants to take a particular
S-PE out of loopback mode, the message SHOULD also carry the SP-PE
TLV which identifies the target S-PE. If the PW is taken out of
loopback mode successfully, the receiving PE/T-PE/S-PE SHOULD send a
Notification message with PW status bit "Pseudowire in Loopback Mode"
cleared. Otherwise, it SHOULD send a Notification message with the
LDP Status code set to "Exit Loopback Failure" , and the Status bit
"Pseudowire in Loopback Mode" MUST still be set. For the S-PE case,
An SP-PE TLV identifying the S-PE SHOULD also be carried in the
Notification message.
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4. IANA Considerations
Two bits ("Lock" (K) and "Loopback" (B)) as defined in section 2.1
need to be allocated in the MPLS-TP PW OAM Administration TLV.
Two new PW Status bits as defined in section 2.2 need to be allocated
in the "Pseudowire Status Codes" Registry.
Four new LDP status codes need be assigned by the IANA in the LDP
"STATUS CODE NAME SPACE":
Range/Value E Description
TBA 0 Lock Failure
TBA 0 Unlock Failure
TBA 0 Enter Loopback Failure
TBA 0 Exit Loopback Failure
5. Security Considerations
TBD
6. Acknowledgements
TBD
7. References
7.1. Normative References
[I-D.ietf-pwe3-oam-config]
Zhang, F., Wu, B., and E. Bellagamba, "Label Distribution
Protocol Extensions for Proactive Operations,
Administration and Maintenance Configuration of Dynamic
MPLS Transport Profile PseudoWire",
draft-ietf-pwe3-oam-config-00 (work in progress),
September 2011.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3985] Bryant, S. and P. Pate, "Pseudo Wire Emulation Edge-to-
Edge (PWE3) Architecture", RFC 3985, March 2005.
[RFC4447] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G.
Heron, "Pseudowire Setup and Maintenance Using the Label
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Distribution Protocol (LDP)", RFC 4447, April 2006.
[RFC5659] Bocci, M. and S. Bryant, "An Architecture for Multi-
Segment Pseudowire Emulation Edge-to-Edge", RFC 5659,
October 2009.
[RFC5860] Vigoureux, M., Ward, D., and M. Betts, "Requirements for
Operations, Administration, and Maintenance (OAM) in MPLS
Transport Networks", RFC 5860, May 2010.
[RFC6073] Martini, L., Metz, C., Nadeau, T., Bocci, M., and M.
Aissaoui, "Segmented Pseudowire", RFC 6073, January 2011.
[RFC6371] Busi, I. and D. Allan, "Operations, Administration, and
Maintenance Framework for MPLS-Based Transport Networks",
RFC 6371, September 2011.
7.2. Informative References
[RFC5586] Bocci, M., Vigoureux, M., and S. Bryant, "MPLS Generic
Associated Channel", RFC 5586, June 2009.
[RFC6435] Boutros, S., Sivabalan, S., Aggarwal, R., Vigoureux, M.,
and X. Dai, "MPLS Transport Profile Lock Instruct and
Loopback Functions", RFC 6435, November 2011.
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
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Greg Mirsky
Ericsson
Email: gregory.mirsky@ericsson.com
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