MPLS Working Group G. Liu
Internet-Draft ZTE Corporation
Intended status: Informational Y. Weingarten
Expires: April 26, 2012 Nokia Siemens Networks
October 24, 2011
MPLS-TP protection for interconnected rings
draft-liu-mpls-tp-interconnected-ring-protection-00
Abstract
According to the ring protection Requirements in RFC 5654,
Requirement 93 : When a network is constructed from interconnected
rings, MPLS-TP MUST support recovery mechanisms that protect user
data that traverses more than one ring. This includes the
possibility of failure of the ring-interconnect nodes and links,so
this document will describle all kinds of interconnected rings
Scenario and a few possible solutions for recovery the failure of the
ring-interconnect nodes and Links. .
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 April 26, 2012.
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Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions used in this document . . . . . . . . . . . . . . 7
3. recovery mechanisms . . . . . . . . . . . . . . . . . . . . . 8
3.1. recovery mechanism for Dual-node interconnected-ring . . . 8
3.2. recovery mechanism for Single-node interconnected-ring . . 8
3.3. recovery mechanism for Chained interconnected-ring . . . . 8
3.4. recovery mechanism for Dual-node and Single-node mix
interconnected-ring . . . . . . . . . . . . . . . . . . . 9
3.5. recovery mechanism for Dual-node and Chained mix
interconnected-ring . . . . . . . . . . . . . . . . . . . 9
3.6. recovery mechanism for Single-node and Chained mix
interconnected-ring . . . . . . . . . . . . . . . . . . . 9
3.7. recovery mechanism for Dual-node ,Single-node and
Chained mix interconnected-ring . . . . . . . . . . . . . 9
4. Security Considerations . . . . . . . . . . . . . . . . . . . 9
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7.1. Normative References . . . . . . . . . . . . . . . . . . . 10
7.2. Informative References . . . . . . . . . . . . . . . . . . 10
7.3. URL References . . . . . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10
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1. Introduction
This first version of the document will simply describle all kinds of
interconnected rings scenario and a few protection solutions for the
failure of the ring-interconnect nodes and links. For interconnected
rings between two rings, there are mainly include three common
interconnection scenario:
Dual-node interconnection - when the interconnected rings are
interconnected by two nodes from each ring (see Figure 1);
Single-node interconnection - when the connection between the
interconnected rings are through a single node (see Figure 2);
Chain of rings - when a series of rings are connected through
interconnection nodes that are part of both interconnected rings (see
Figure 3)
/LSR\******/LSR\******/LSR\xxxx/LSR\*****/LSR\******/LSR\
\_C_/ \_B_/ \_A_/ \_6_/ \_1_/ \_2_/
* * * *
* Ring #1 * * Ring #2 *
_*_ ___ _*_ _*_ ___ _*_
/LSR\ /LSR\ /LSR\ /LSR\ /LSR\ /LSR\
\_D_/******\_E_/******\_F_/xxxx\_5_/*****\_4_/******\_3_/
*** physical link
xxx interconnection link
Figure 1
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___ ___ ___ ___
/LSR\**********/LSR\ /LSR\*********/LSR\
\_C_/ \_B_/* *\_1_/ \_2_/
* * * *
* * * *
* * * *
_*_ * ___ * _*_
/LSR\ Ring #1 /LSR\ Ring #2 /LSR\
\_D_/ *\_A_/* \_3_/
* * * *
* * * *
* * * *
_*_ ___* *___ _*_
/LSR\ /LSR\ /LSR\ /LSR\
\_E_/***********\_F_/ \_5_/**********\_4_/
*** physical link
Figure 2
___ ___ ___ ___ ___
/LSR\******/LSR\******/LSR\*****/LSR\******/LSR\
\_C_/ \_B_/ \_A_/ \_1_/ \_2_/
* x *
* Ring #1 x Ring #2 *
_*_ ___ _x_ ___ _*_
/LSR\ /LSR\ /LSR\ /LSR\ /LSR\
\_D_/******\_E_/******\_F_/*****\_4_/******\_3_/
*** physical link
xxx shared link
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Figure 3
when a traffic traveres more than two rings.there are mainly the
following mix interconnection scenarios:
Dual-node and single-node mix interconnection-when there not only
exist two interconnected rings are interconnected by two nodes from
each ring. but also there exist two interconnected rings are
interconnected by single node( see figure 5);
Dual-node and chained mix interconnection-when there exist two
interconnnected rings are interconnected by two nodes from each ring.
in addtion, there still exist two interconnnected rings are
interconnected by a common chained link(see figure 4);
single-node and chained mix interconnection-when there exist two
interconnected rings are interconnected by single node, in addtion,
there still exist two interconnected rings are interconnected by a
common chained link(see figure 6);
Dual-node, single-node and chained mix interconnection-when there
exist all three interconnection scenrios in the network domain
including Dual-node interconnnection, single-node interconnection and
chained interconnnection( see figure 7);
___
/LSR\******/LSR\xx/LSR\****/LSR\ /LSR\**** /LSR\***/LSR\
\_C_/ \_B_/ \_A_/ \_6_/ \_1_/ \_2_/ \_H_/
* * * * * x *
* x *
* Ring 1 * * Ring 2 * .....*Ring 3 x Ring 4*
_*_ *_ _*_ _*_ ___ ___ ___
/LSR\ /LSR\ /LSR\ /LSR\ /LSR\*****/LSR\**/LSR\
\_D_/******\_E_/xx\_5_/*****\_4_/ \_k_/ \_L_/ \_M_/
*** physical link
xxx interconnection link
Figure 4
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___
/LSR\******/LSR\xx/LSR\****/LSR\ /LSR\ /LSR\
\_C_/ \_B_/ \_A_/ \_6_/ \_1_/ *\_H_/
* * * * * * * *
* * ___ * *
* Ring 1 * * Ring 2 * .....*Ring 3/LSR\ Ring 4*
_*_ *_ _*_ _*_ ___ * \_L_/* ___
/LSR\ /LSR\ /LSR\ /LSR\ /LSR\* * /LSR\
\_D_/******\_E_/xx\_5_/*****\_4_/ \_k_/ \_M_/
*** physical link
xxx interconnection link
Figure 5
___
/LSR\******/LSR\**/LSR\****/LSR\ /LSR\ /LSR\
\_C_/ \_B_/ \_A_/ \_6_/ \_1_/ *\_H_/
* x * * * * *
* * ___ * *
* Ring 1 x Ring 2 * .....*Ring 3/LSR\ Ring 4*
_*_ _ _x_ _*_ ___ * \_L_/* ___
/LSR\ /LSR\ /LSR\ /LSR\ /LSR\* * /LSR\
\_D_/******\_E_/**\_5_/*****\_4_/ \_k_/ *\_M_/
*** physical link
xxx interconnection link
Figure 6
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___
/LSR\******/LSR\xx/LSR\****/LSR\**** /LSR\ /LSR\
\_C_/ \_B_/ \_A_/ \_6_/ \_1_/ *\_H_/
* * * x x * * *
x * ___ * *
* Ring 1 * * Ring 2 xRing 5 xRing 3/LSR\ Ring 4*
_*_ *_ _*_ _x_ ___ * \_L_/* ___
/LSR\ /LSR\ /LSR\ /LSR\****/LSR\* * /LSR\
\_D_/******\_E_/xx\_5_/*****\_4_/ \_k_/ *\_M_/
*** physical link
xxx interconnection link
Figure 7
For a multi-ring service, it will be accross more than one ring just
like above seven scenrios. if a failur happens on a multi-ring path,
quickly recovery is necessary requirement for MPLS-TP network, so
there are describles for recoverying the failure in the multi-ring
interconnection sencrios in the following sections .
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.
TLV: Type Length Value
P2MP:Point to Multi-Point
P2P:Point to Point
PSC:Protection Switching Coordination
SD:Signal Degrade
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SF:Signal Fail
RDI:Remote Defect Indication
SPME:Sub-Path Maintenance Entity
MPLS-TP:Multi-Protocol Label Switching Transport Profile
ME: Maintenance Entity
MEP:MEG End Point
ACH: Associated Channel Header
CC-V: Contunuity Check-Verification;
3. recovery mechanisms
This section will describle recovery mechanisms that protect multi-
ring traffics,which traver more than one ring in case of failure for
all kinds of interconnection-ring scenrios;
3.1. recovery mechanism for Dual-node interconnected-ring
Under the interconnected-ring scenrios just as figure 1,multi-ring
traffics will be transported by interconnection link(LSR C-LSR 6).
when a failure happened on the interconnection link, if a segment
protection path has been set up for the interconnection link , maybe
apply 1:1 linear protection to protect the interconnection link
faiure for interconnected-ring; or else, it maybe need end to end
multi-ring path switch to protect the interconnection link failure. .
3.2. recovery mechanism for Single-node interconnected-ring
for the single-node interconnected-ring scenrio, As the
interconnection node (LSR-A in Figure 2) is a single-point of failure
, such an interconnection scheme should be avoided. .
3.3. recovery mechanism for Chained interconnected-ring
For the chained interconnected-ring scenrio, if the interconnection
nodes(LSR-A and LSR-F) or the shared link(LSR-A-LSR-F) have failures,
single ring protection solution can't recovery the failure, so the
affected multi-ring traffics maybe be protected by end to end
protection path; .
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3.4. recovery mechanism for Dual-node and Single-node mix
interconnected-ring
for the mix interconnected-ring scenrios, each interconnection nodes
or shared interconnection link will be protected by setting up
segment protection path seperately. in addition, it may still use end
to end multi-ring protection path to protect multiple interconnection
nodes or shared interconnection link failure. .
3.5. recovery mechanism for Dual-node and Chained mix interconnected-
ring
. for the mix interconnected-ring scenrios, each interconnection
nodes or shared interconnection link will be protected by setting up
segment protection path seperately. in addition, it may still use end
to end multi-ring protection path to protect multiple interconnection
nodes or shared interconnection link failure.
3.6. recovery mechanism for Single-node and Chained mix interconnected-
ring
for the mix interconnected-ring scenrios, each interconnection nodes
or shared interconnection link will be protected by setting up
segment protection path seperately. in addition, it may still use end
to end multi-ring protection path to protect multiple interconnection
nodes or shared interconnection link failure.
3.7. recovery mechanism for Dual-node ,Single-node and Chained mix
interconnected-ring
for the mix interconnected-ring scenrios, each interconnection nodes
or shared interconnection link will be protected by setting up
segment protection path seperately. in addition, it may still use end
to end multi-ring protection path to protect multiple interconnection
nodes or shared interconnection link failure.
4. Security Considerations
TBD
5. IANA Considerations
TBD.
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6. Acknowledgments
TBD .
7. References
7.1. Normative References
[RFC 5654]
IETF, "IETF RFC5654(MPLS-TP requirement)", September 2009.
[RFC 5921]
IETF, "IETF RFC5654(MPLS-TP framework)", July 2010.
[RFC 6372]
N. Sprecher, A. Farrel, "Multiprotocol Label Switching
Transport Profile Survivability Framework",
September 2011.
7.2. Informative References
[MPLS-TP Linear protection]
S. Bryant, N. Sprecher, H. van Helvoort,A. Fulignoli Y.
Weingarten, "MPLS transport profile Linear Protection",
July 2010.
[MPLS-TP Ring Protection]
Y. Weingarten, "Multiprotocol Label Switching Transport
Profile Ring Protection", Sep 2011.
7.3. URL References
[MPLS-TP-22]
IETF - ITU-T Joint Working Team, "", 2008,
<http://www.example.com/dominator.html>.
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Authors' Addresses
Liu guoman
ZTE Corporation
No.50, Ruanjian Road, Yuhuatai District
Nanjing 210012
P.R.China
Phone: +86 025 52871606
Email: liu.guoman@zte.com.cn
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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