One document matched: draft-fuxh-mpls-tp-transfer-framework-00.txt
Network Working Group X. Fu
Internet-Draft Y. Bao
Intended status: Standards Track ZTE Corporation
Expires: September 2, 2010 March 1, 2010
Framework for MPLS-TP Ownership Transfer Between Management Plane and
Control Plane
draft-fuxh-mpls-tp-transfer-framework-00
Abstract
In MPLS-TP architecture, LSP and PW provisioning can be done either
by Control Plane (CP) or Management Plane (MP). The MPLS-TP control
plane must provide a mechanism for dynamic ownership transfer of the
control of MPLS-TP transport paths from MP to CP and vice versa.
[draft-bao-mpls-tp-path-transfer-reqs-00] defines requirement for
MPLS-TP paths ownership transfer from MP to CP and vice versa.
This document provides a framework to allow the development of
protocol extensions to support the MPLS-TP paths ownership transfer
between MP and CP and vice versa.
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 RFC 2119 [RFC2119].
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 2, 2010.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Ownership Transfer Procedures . . . . . . . . . . . . . . . . . 3
2.1. Ownership Transfer Procedure for Associated LSP . . . . . . 3
2.1.1. Associated LSP Ownership Transfer From MP to CP . . . . 3
2.1.2. Associated LSP Ownership Transfer From CP to MP . . . . 4
2.2. Ownership Transfer Procedures for PW . . . . . . . . . . . 4
2.2.1. PW Ownership Transfer From MP to CP . . . . . . . . . . 4
2.2.2. PW Ownership Transfer From CP to MP . . . . . . . . . . 7
3. Security Considerations . . . . . . . . . . . . . . . . . . . . 8
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8
5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1. Normative References . . . . . . . . . . . . . . . . . . . 8
5.2. Informative References . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
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1. Introduction
In terms of MPLS-TP requirement, an MPLS-TP control plane MUST
provide a mechanism for dynamic ownership transfer of the control of
MPLS-TP transport paths from the Management Plane (MP) to the Control
Plane (CP) and vice versa. In MPLS-TP architecture, LSP and PW
provisioning can be done either by Control Plane or Management Plane.
The MPLS-TP control plane must support unidirectional, associated
bidirectional and co-routed bidirectional point-to-point transport
paths. [RFC5493] defines the specific requirements for an LSP
ownership transfer procedure. [PC-SPC] describes an extension to
GMPLS RSVP-TE signaling that enables the LSP ownership transfer
between the Management Plane and the Control Plane.
Ownership transfers of the forward and the backward directions
belonging to the same associated bidirectional transport path can't
be done in the same signaling procedure. Edge nodes (i.e., ingress,
egress and intermediate) must be aware about the pairing relationship
of the forward and the backward directions belonging to the same
associated bidirectional transport path. Ownership transfer
procedures of the forward and the backward directions must be
associated. This document describes the ownership transfer related
procedures for associated LSP.
[draft-bao-mpls-tp-path-transfer-reqs-00] defines the requirements
for ownership transfer of existing PWs provisioned by NMS from the MP
to the CP without disrupting user traffic flowing on them. This
document describes the ownership transfer related procedures for PWs.
2. Ownership Transfer Procedures
The ownership transfer of unidirectional and co-routed bidirectional
LSPs is based on the [RFC5493] and [PC-SPC]
2.1. Ownership Transfer Procedure for Associated LSP
2.1.1. Associated LSP Ownership Transfer From MP to CP
Forward and backward paths belonging to the same associated LSP are
signalled/routed independently in MPLS-TP networks. So ownership
transfers from MP to CP of the forward and the backward directions
belonging to the same associated bidirectional transport path can't
be done in the same signaling procedure. But ownership transfer of
each direction should be based on [RFC5493] and [PC-SPC].
In order to make edge nodes (i.e., ingress, egress and intermediate)
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be aware about the pairing relationship of the forward and the
backward directions belonging to the same associated bidirectional
transport path, ownership transfer procedures of the forward and the
backward directions must be associated.
The ASSOCIATION object, as defined in RFC 4872 and RFC 4873
respectively, is used to provide end-to-end and segment recovery.
Furthermore, draft-berger-ccamp-assoc-info-00.txt described how to
utilize it in detail.
[draft-zhang-mpls-tp-rsvpte-ext-associated-lsp-00] defines a
mechanism to associated the forward and the backward direction LSPs
to be an associated LSP. It extends the ASSOCIATION Object and
defines a new Association Type. An ASSOCIATION object with an
Association Type set to the value "Association" is used to bind two
reverse unidirectional LSP to be an associated bidirectional LSP.
Any node originating the forward or backward direction LSP MUST
insert an ASSOCIATION object with an Association Type set to the
value "Association". The Association ID MUST be set to a value that
uniquely identifies the reverse direction LSP. Egress or
intermediate nodes MUST use ASSOCIATION object(s) with the
Association Type set to the value "Association" to bind the two
reverse unidirectional LSPs together.
2.1.2. Associated LSP Ownership Transfer From CP to MP
Ownership transfers from CP to MP of the forward and the backward
directions belonging to the same associated bidirectional transport
path also can't be done in the same signaling procedure. But
ownership transfer from CP to MP of each direction should be based on
[RFC5493] and [PC-SPC].
2.2. Ownership Transfer Procedures for PW
2.2.1. PW Ownership Transfer From MP to CP
2.2.1.1. SS-PW Ownership Transfer From MP to CP
SS-PW in MPLS-TP network signaling control plane is based on LDP with
specific procedures defined in [RFC4447]. [Segmented-PW] and [MS-PW]
allow for static switching of multi-segment pseudowires whereby
signaling is still based on Targeted LDP (T-LDP). The ownership
transfer procedure from MP to CP for PW (SS-PW and MS-PW) MUST create
LDP sessions along the path which is transfered.
The ownership transfer procedure for SS-PW must create an LDP session
between PE1 and PE2. The ownership transfer procecure for SS-PW MUST
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NOT cause any disruption of user traffic flowing over the PW whose
control is being transferred. If the ownership transfer fails, the
data plane MUST not be affected.
The operator can synchronously instruct PE1 and PE2 to transfer
control of the PW from the MP to the CP. PE1 initiates the ownership
transfer by sending a Label Mapping Message to the ingress PE (PE2).
PE2 also initiates the ownership transfer by sending a Label Mapping
Message to the ingress PE (PE1). The Label Mapping message contains
an FEC TLV, a Label TLV, and optional parameter TLVs. The signaling
procedure must be based on [RFC4447].
The Status TLV defined in [RFC3337] is transported to the remote PW
peer via the LDP Notification message.
[draft-bao-pw3-pw-transfer-ldp-ext-00] defines an LDP extension by
adding a PW Ownership Handover TLV to provide a mechanism to identify
the LDP message of ownership transfer. The Egress node originating
the LDP Mapping message of ownership transfer must insert a PW
Ownership Handover TLV with a flag set to the value "Handover". The
ingress that receives a LDP message must use the flag set to the
value "Handover" to identify ownership transfer. It should not do
the FEC and Label Mapping anymore.
|<-------------- Emulated Service ---------------->|
| |
| |<------- Pseudowire ------->| |
| | | |
|Attachment| |<-- PSN Tunnel -->| |Attachment|
| Circuit V V V V Circuit |
V (AC) +----+ +----+ (AC) V
+-----+ | | PE1|==================| PE2| | +-----+
| |----------|............PW1.............|----------| |
| CE1 | | | | | | | | CE2 |
| |----------|............PW2.............|----------| |
+-----+ ^ | | |==================| | | ^ +-----+
^ | +----+ +----+ | | ^
| | Provider Edge 1 Provider Edge 2 | |
| | | |
Customer | | Customer
Edge 1 | | Edge 2
| |
native service native service
Figure 1: SS-PWE Reference Model
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2.2.1.2. MS-PW Ownership Transfer From MP to CP
The ownership transfer procedure for MS-PW must also create LDP
sessions between T-PE1 and S-PE1, S-PE1 and S-PE2, and the other one
between S-PE2 and T-PE2.
The operator instructs T-PE1 to transfer control of the PW from the
MP to the CP. In order to creat LDP sessions along the path of
MS-PW, operator must give full information about the explicit route
of MS-PW including the S-PEs (S-PE1 and S-PE2) traversed by PW.
The ownership transfer procedure of each PW segment is based on the
section 2.2.1.1, but the Label Mapping message must carry the
explicit route of MS-PW including S-PE1 and S-PE2 encoded in S-PE
TLV. After S-PE1 receive the Label Mapping message, it needs to get
the next S-PEs (S-PE2) from the S-PE TLV and create the LDP session
between S-PE1 and S-PE2.
The node originating the LDP Mapping message of ownership transfer
must insert a PW Ownership Handover TLV with a flag set to the value
"Handover" defined in [draft-bao-pw3-pw-transfer-ldp-ext-00]. The
ingress that receives a LDP Mapping message must use the flag set to
the value "Handover" to identify ownership transfer. It should not
do the FEC and Label Mapping anymore.
Native |<---------------------- MS-PW ---------------------->| Native
Service | |<-PSN1-->| |<--PSN2->| |<--PSN3->| | Service
(AC) V V V V V V V V (AC)
| +-----+ +-----+ +-----+ +-----+
+----+ | |T-PE1| |S-PE1| |S-PE2| |T-PE2| | +----+
| | | | |=========| |=========| |=========| | | | |
| |------|......PW.Seg't1.......PW Seg't3.......PW Seg't5......|-----| |
| CE1| | | | | | | | | | | |CE2 |
| |------|......PW.Seg't2......|PW Seg't4......|PW Seg't6......|-----| |
| | | | |=========| |=========| |=========| | | | |
+----+ +-----+ +-----+ +-----+ +-----+ +----+
^ ^
| |
| |
|<----------------------- Emulated Service ----------------------->|
Figure 2: MS-PW switching Reference Model
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2.2.2. PW Ownership Transfer From CP to MP
The CP has the ownership and control of the PW. The CP to MP
transfer procedure MUST delete the existing LDP session information
and MUST NOT affect the cross-connected resources, but just move
their ownership to the MP.
2.2.2.1. SS-PW Ownership Transfer From MP to CP
The ownership transfer procedure for SS-PW must delete the existing
LDP session between PE1 and PE2. .
The operator can synchronously instruct PE1 and PE2 to transfer
control of the PW from the CP to the MP. PE1 initiates the ownership
transfer by sending a Label Withdraw message to the ingress PE (PE2).
PE2 also initiates the ownership transfer by sending a Label Withdraw
message to the ingress PE (PE1). The signaling procedure must be
based on [RFC4447].
[draft-bao-pw3-pw-transfer-ldp-ext-00] defines an LDP extension by
adding a PW Ownership Handover TLV to provide a mechanism to identify
the LDP message of ownership transfer. The Egress node originating
the Label Withdraw message of ownership transfer must insert a PW
Ownership Handover TLV with a flag set to the value "Handover". The
ingress that receives a Label Withdraw message must use the flag set
to the value "Handover" to identify ownership transfer. There is no
any action is taken over the Data Plane anymore.
2.2.2.2. MS-PW Ownership Transfer From MP to CP
The ownership transfer procedure for MS-PW must also delete LDP
sessions between T-PE1 and S-PE1, S-PE1 and S-PE2, and the other one
between S-PE2 and T-PE2.
The operator instructs T-PE1 to transfer control of the PW from the
CP to the MP. In order to delete LDP sessions along the path of
MS-PW, the CP must give full information about the explicit route of
MS-PW including the S-PEs (S-PE1 and S-PE2) traversed by PW.
The ownership transfer procedure of each PW segment is based on the
section 2.2.2.1, but the Label Withdraw message must carry the
explicit route of MS-PW including S-PE1 and S-PE2 encoded in S-PE
TLV. After S-PE1 receive the Label Withdraw message, it needs to get
the next S-PEs (S-PE2) from the S-PE TLV and delete the LDP session
between S-PE1 and S-PE2.
The node originating the LDP Withdraw message of ownership transfer
must insert a PW Ownership Handover TLV with a flag set to the value
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"Handover" defined in [draft-bao-pw3-pw-transfer-ldp-ext-00]. The
ingress that receives a LDP Withdraw message must use the flag set to
the value "Handover" to identify ownership transfer. There is no any
action is taken over the Data Plane anymore.
3. Security Considerations
TBD
4. IANA Considerations
TBD
5. References
5.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3036] Andersson, L., Doolan, P., Feldman, N., Fredette, A., and
B. Thomas, "LDP Specification", RFC 3036, January 2001.
[RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP
Specification", RFC 5036, October 2007.
[RFC4447] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G.
Heron, "Pseudowire Setup and Maintenance Using the Label
Distribution Protocol (LDP)", RFC 4447, April 2006.
[RFC5493] Caviglia, D., Bramanti, D., Li, D., and D. McDysan,
"Requirements for the Conversion between Permanent
Connections and Switched Connections in a Generalized
Multiprotocol Label Switching (GMPLS) Network", RFC 5493,
April 2009.
[RFC5654] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N.,
and S. Ueno, "Requirements of an MPLS Transport Profile",
RFC 5654, September 2009.
5.2. Informative References
[I-D.ietf-ccamp-pc-spc-rsvpte-ext]
Caviglia, D., Ceccarelli, D., Li, D., and S. Bardalai,
"RSVP-TE Signaling Extension For Management Plane To
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Control Plane LSP Handover In A GMPLS Enabled Transport
Network.", draft-ietf-ccamp-pc-spc-rsvpte-ext-07 (work in
progress), February 2010.
[I-D.ietf-pwe3-ms-pw-arch]
Bocci, M. and S. Bryant, "An Architecture for Multi-
Segment Pseudowire Emulation Edge-to-Edge",
draft-ietf-pwe3-ms-pw-arch-07 (work in progress),
July 2009.
[I-D.abfb-mpls-tp-control-plane-framework]
Andersson, L., Berger, L., Fang, L., Bitar, N., Takacs,
A., Vigoureux, M., and E. Bellagamba, "MPLS-TP Control
Plane Framework",
draft-abfb-mpls-tp-control-plane-framework-02 (work in
progress), February 2010.
[I-D.ietf-mpls-tp-framework]
Bocci, M., Bryant, S., Frost, D., Levrau, L., and L.
Berger, "A Framework for MPLS in Transport Networks",
draft-ietf-mpls-tp-framework-10 (work in progress),
February 2010.
Authors' Addresses
Xihua Fu
ZTE Corporation
West District,ZTE Plaza,No.10,Tangyan South Road,Gaoxin District
Xi An 710065
P.R.China
Phone: +8613798412242
Email: fu.xihua@zte.com.cn
URI: http://wwwen.zte.com.cn/
Yuanlin Bao
ZTE Corporation
5F,R&D Building 3, ZTE Industrial Park, XiLi LiuXian Road
Nanshan District,Shenzhen 518055
P.R.China
Phone: +86 755 26773731
Email: bao.yuanlin@zte.com.cn
URI: http://wwwen.zte.com.cn/
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