Internet DRAFT - draft-liu-pwe3-mpls-tp-p2mp-pw-protection
draft-liu-pwe3-mpls-tp-p2mp-pw-protection
MPLS Working Group G. Liu
Internet-Draft J. Yu
Intended status: Informational X. Tu
Expires: July 2, 2012 X. Xu
ZTE Corporation
December 30, 2011
p2mp pw protection for mpls-tp network
draft-liu-pwe3-mpls-tp-p2mp-pw-protection-00
Abstract
According to one protection Requirement in RFC 5654, Requirement 63
:It MUST be possible to provide protection for the MPLS-TP data plane
without any IP forwarding capability in the MPLS-TP data plane. and
it requires mpls-tp date plane should be independent of its control
plane. so it is necessary for the 1:1 protection of p2mp pw to have a
return path to coordinate the switch state between root node and each
leaf node. for the above problem statement, the document provides a
solution to protect p2mp pw by using one leaf node as protector for
another leaf node. so it may avoid setting up a return path for each
leaf node.
This document is a product of a joint Internet Task Force(IETF) /
International Telecommunications Union Telecommunications
Standardization Sector (ITU-T) effort to include an MPLS Transport
Profile within the IETF MPLS and PWE3 architectures to support the
capabilities and functionalities of a packet transport network as
defined by the ITU-T.
Status of this Memo
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provisions of BCP 78 and BCP 79. This document may not be modified,
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This Internet-Draft will expire on July 2, 2012.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
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Table of Contents
1. Problem statement . . . . . . . . . . . . . . . . . . . . . . . 4
2. Conventions used in this document . . . . . . . . . . . . . . . 4
3. protection solution . . . . . . . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 8
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.1. Normative References . . . . . . . . . . . . . . . . . . . 9
7.2. Informative References . . . . . . . . . . . . . . . . . . 9
7.3. URL References . . . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
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1. Problem statement
according to mpls-tp requirement(RFC 5654), it requires mpls-tp data
plane is independent of control plane. it means that mpls-tp data
plane can still work without control plane or under the condition of
failure on the control plane. at the same time, mpls-tp data plane
can forward traffic packet without any IP forwarding capability.so it
must be essential for uni-directional path including p2p or p2mp pw
to set up a return path between two end nodes in order to communicate
and associate between the two end nodes. so it needs to set up more
return paths for p2mp pw, it will need more configuration and
maintenece cost. so the document provide one protection solution for
p2mp pw under the condition without return path,IP forwarding
capability and control plane.
2. 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.
OAM: Operations, Administration, Maintenance
LSP: Label Switched Path.
PW: Pseudowire
P2MP:Point to Multi-Point
P2P:Point to Point
PSC:Protection Switching Coordination
CE:Customer Equipment
LER:Label Edge Router
LSR:Label Switch Router
PSN:Packet Switch Network
MPLS-TP:Multi-Protocol Label Switching Transport Profile
ME: Maintenance Entity
MEP:MEG End Point
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ACH: Associated Channel Header
CC-V: Contunuity Check-Verification;
3. protection solution
This section will describle the protection solution for p2mp pw in
detail,which use one leaf node as protector node of another leaf
node. and the two leaf nodes is backup for each other.in addtion, in
order to be easy to access to CE node, it should set up backup node
to directly access to CE node. if backup node is still a leaf node of
the p2mp pw, protector node and backup node are the same node. at the
same time, it should set up a bidirectional p2p pw between protected
node, backup node and protector node .just as the following figure 1:
___ ___ ___
*/LSR\ ********* /LER\********** /CE1\
* \ A / \_1_/ + \___/
__ * - - + +
/LER\* . _+_ +
/LER\+
\_O_/* . \_2_/+
* . + +
* ___ _+_ + ___
* /LSR\ /LER\ + /CE3\
* \ B / ********** \_3_/*********** \___/
- -
***** working pw
+++++ protection pw
Figure 1
LER 0 is the root node of the p2mp pw, LER 1 and LER 3 are leaf nodes
of the p2mp pw. LER 2 is backup node for LER 1 and LER 3. when
protected node LER 1 or LER 3 has the failure, backup node LER 2 will
replace of protected node LER 1 or LER 3 to transmit traffic packet
to CE1 or CE3. for CE1 or CE3 node, if it detect a failure on its
working access link(*), it will select protection access link(+) to
receive the traffic.for example, just as the following figure 2:
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___ ___ ___
*/LSR\ ********* /LER\****X***** /CE1\
* \ A / \_1_/ + \___/
__ * - - X +
/LER\* . _+_ +
/LER\+
\_O_/* . \_2_/+
* . + +
* ___ _+_ + ___
* /LSR\ /LER\ + /CE3\
* \ B / ********** \_3_/*********** \___/
- -
***** working pw
+++++ protection pw
X failure
Figure 2
if the LER 1 has the failure, CE1 and LER 2 MUST detect the failure
by OAM or other function. then LER 2 will notify protector node LER 3
of the failure by pw status message[1]. then LER 3 will begin to
duplicate the service packet of the p2mp pw to transmit to LER 2 by
pre-configured p2p protection pw. then the LER 2 send the service
packet of the p2mp pw to CE1 by protection access link(LER2-CE1).and
CE1 detects the failure on its working access link(LER1-CE1), it must
switch to protection access link(LER2-CE1) to receive the service. at
the same time, if another protected node LER3 has the failure, it may
use the same method to protect the failure of LER3.
when there is only the failure on the working access link just as the
following figure 3:
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___ ___ ___
*/LSR\ ********* /LER\****X***** /CE1\
* \ A / \_1_/ + \___/
__ * - - + +
/LER\* . _+_ +
/LER\+
\_O_/* . \_2_/+
* . + +
* ___ _+_ + ___
* /LSR\ /LER\ + /CE3\
* \ B / ********** \_3_/*********** \___/
- -
***** working pw
+++++ protection pw
X failure
Figure 3
when CE1 and LER1 detect a failure on the working access link(LER1-
CE1), LER1 firstly notify backup node LER2 of the egress AC failure
by pw status message. then LER1 will send the service packet of the
p2mp pw to LER2 by protection pw between LER1 and LER2. and LER2 will
transmit the service packet of the p2mp pw to CE1 by protection
access link(LER2-CE1). at the same time, CE1 will switch to
protection access link(LER2-CE1) to receive the service packet.
when the protected node detects a failure on its working pw , it will
notify the failure of its backup node or protector node. so that the
backup node will transmit the service packet of the p2mp pw to the
protected node.it is just as the following figure 4:
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___ ___ ___
*/LSR\ *****X**** /LER\********* /CE1\
* \ A / \_1_/ + \___/
__ * - - + +
/LER\* . _+_ +
/LER\+
\_O_/* . \_2_/+
* . + +
* ___ _+_ + ___
* /LSR\ /LER\ + /CE3\
* \ B / ********** \_3_/*********** \___/
- -
***** working pw
+++++ protection pw
X failure
Figure 4
when the failure happens on the branch working path(LER0-LSR A-LER
1), the protector node LER1 will notify the failure message of the
backup node LER2 or protector node LER3. and then LER2 or LER3
receives the failure message from LER1 ,LER3 will duplicate the
service packet of the p2mp pw to transmit it to backup node LER2
firstly. then LER2 continue to transmit the service packet of the
p2mp pw to the protector node LER1. at last LER1 will transmit it to
CE1 by its working access link(LER1-CE1).
4. Security Considerations
TBD
5. IANA Considerations
TBD.
6. Acknowledgments
TBD .
7. References
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7.1. Normative References
[RFC 5654]
IETF, "IETF RFC5654(MPLS-TP requirement)", September 2009.
[RFC 5921]
IETF, "IETF RFC5654(MPLS-TP framework)", July 2010.
7.2. Informative References
[draft-ietf-pwe3-redundancy-05]
Praveen Muley, Mustapha Aissaoui,Matthew Bocci,
"Pseudowire Redundancy", September 2011.
[draft-ietf-pwe3-redundancy-bit-05]
Praveen Muley, Mustapha Aissaoui, "Pseudowire Preferential
Forwarding Status Bit", September 2011.
[draft-ietf-pwe3-static-pw-status-10]
Luca Martini,George Swallow,Giles Heron,Matthew Bocci,
"Pseudowire Status for Static Pseudowires", November 2011.
7.3. URL References
[MPLS-TP-22]
IETF - ITU-T Joint Working Team, "", 2008,
<http://www.example.com/dominator.html>.
Authors' Addresses
Liu guoman
ZTE Corporation
No.50, Ruanjian Road, Yuhuatai District
Nanjing 210012
P.R.China
Phone: +86 025 88014227
Email: liu.guoman@zte.com.cn
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Yu jinghai
ZTE Corporation
No.50, Ruanjian Road, Yuhuatai District
Nanjing 45241
P.R China
Phone: +86 025 88014226
Email: yu.jinghai@zte.com.cn
Tu xiaoping
ZTE Corporation
No.50, Ruanjian Road, Yuhuatai District
Nanjing 45241
P.R China
Phone: +86 025 88014226
Email: Tu.xiaoping@zte.com.cn
xu xueqiong
ZTE Corporation
No.50, Ruanjian Road, Yuhuatai District
Nanjing 45241
P.R China
Phone: +86 025 88014226
Email: Xu.xueqiong@zte.com.cn
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