draft-ietf-teas-gmpls-resource-sharing-proc-07.txt   draft-ietf-teas-gmpls-resource-sharing-proc-08.txt 
TEAS Working Group X. Zhang TEAS Working Group X. Zhang
Internet-Draft H. Zheng, Ed. Internet-Draft H. Zheng, Ed.
Intended Status: Informational Huawei Technologies Intended Status: Informational Huawei Technologies
Expires: July 18, 2017 R. Gandhi, Ed. Expires: July 30, 2017 R. Gandhi, Ed.
Z. Ali Z. Ali
Cisco Systems, Inc. Cisco Systems, Inc.
P. Brzozowski P. Brzozowski
ADVA Optical ADVA Optical
January 14, 2017 January 26, 2017
RSVP-TE Signaling Procedure for End-to-End GMPLS Restoration and RSVP-TE Signaling Procedure for End-to-End GMPLS Restoration and
Resource Sharing Resource Sharing
draft-ietf-teas-gmpls-resource-sharing-proc-07 draft-ietf-teas-gmpls-resource-sharing-proc-08
Abstract Abstract
In non-packet transport networks, there are requirements where In non-packet transport networks, there are requirements where
Generalized Multi-Protocol Label Switching (GMPLS) end-to-end Generalized Multi-Protocol Label Switching (GMPLS) end-to-end
recovery scheme needs to employ restoration Label Switched Path (LSP) recovery scheme needs to employ restoration Label Switched Path (LSP)
while keeping resources for the working and/or protecting LSPs while keeping resources for the working and/or protecting LSPs
reserved in the network after the failure occurs. reserved in the network after the failure occurs.
This document reviews how the LSP association is to be provided using This document reviews how the LSP association is to be provided using
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1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used in This Document . . . . . . . . . . . . . . 4 2. Conventions Used in This Document . . . . . . . . . . . . . . 4
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Acronyms and Abbreviations . . . . . . . . . . . . . . . . 4 2.2. Acronyms and Abbreviations . . . . . . . . . . . . . . . . 4
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Examples of Restoration Schemes . . . . . . . . . . . . . 5 3.1. Examples of Restoration Schemes . . . . . . . . . . . . . 5
3.1.1. 1+R Restoration . . . . . . . . . . . . . . . . . . . 5 3.1.1. 1+R Restoration . . . . . . . . . . . . . . . . . . . 5
3.1.2. 1+1+R Restoration . . . . . . . . . . . . . . . . . . 5 3.1.2. 1+1+R Restoration . . . . . . . . . . . . . . . . . . 5
3.1.2.1. 1+1+R Restoration - Variants . . . . . . . . . . . 6 3.1.2.1. 1+1+R Restoration - Variants . . . . . . . . . . . 6
3.2. Resource Sharing By Restoration LSP . . . . . . . . . . . 7 3.2. Resource Sharing by Restoration LSP . . . . . . . . . . . 7
4. RSVP-TE Signaling Procedure . . . . . . . . . . . . . . . . . 7 4. RSVP-TE Signaling Procedure . . . . . . . . . . . . . . . . . 8
4.1. Restoration LSP Association . . . . . . . . . . . . . . . 7 4.1. Restoration LSP Association . . . . . . . . . . . . . . . 8
4.2. Resource Sharing-based Restoration LSP Setup . . . . . . . 8 4.2. Resource Sharing-based Restoration LSP Setup . . . . . . . 8
4.3. LSP Reversion . . . . . . . . . . . . . . . . . . . . . . 9 4.3. LSP Reversion . . . . . . . . . . . . . . . . . . . . . . 10
4.3.1. Make-while-break Reversion . . . . . . . . . . . . . . 10 4.3.1. Make-while-break Reversion . . . . . . . . . . . . . . 10
4.3.2. Make-before-break Reversion . . . . . . . . . . . . . 11 4.3.2. Make-before-break Reversion . . . . . . . . . . . . . 11
5. Security Considerations . . . . . . . . . . . . . . . . . . . 12 5. Security Considerations . . . . . . . . . . . . . . . . . . . 12
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
7.1. Normative References . . . . . . . . . . . . . . . . . . . 13 7.1. Normative References . . . . . . . . . . . . . . . . . . . 13
7.2. Informative References . . . . . . . . . . . . . . . . . . 13 7.2. Informative References . . . . . . . . . . . . . . . . . . 13
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . 14 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . 14
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
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Path message to identify the LSPs for restoration. Also, an Path message to identify the LSPs for restoration. Also, an
ASSOCIATION object with Association Type "Resource Sharing" [RFC4873] ASSOCIATION object with Association Type "Resource Sharing" [RFC4873]
can be signaled in the RSVP Path message to identify the LSPs for can be signaled in the RSVP Path message to identify the LSPs for
resource sharing. [RFC6689] Section 2.2 reviews the procedure for resource sharing. [RFC6689] Section 2.2 reviews the procedure for
providing LSP associations for GMPLS end-to-end recovery and Section providing LSP associations for GMPLS end-to-end recovery and Section
2.4 reviews the procedure for providing LSP associations for sharing 2.4 reviews the procedure for providing LSP associations for sharing
resources. resources.
Generally GMPLS end-to-end recovery schemes have the restoration LSP Generally GMPLS end-to-end recovery schemes have the restoration LSP
set up after the failure has been detected and notified on the set up after the failure has been detected and notified on the
working LSP. For recovery scheme with revertive behaviour, a working LSP. For recovery scheme with revertive behavior, a
restoration LSP is set up while working LSP and/or protecting LSP are restoration LSP is set up while working LSP and/or protecting LSP are
not torn down in control plane due to a failure. In non-packet not torn down in control plane due to a failure. In non-packet
transport networks, as working LSPs are typically set up over transport networks, as working LSPs are typically set up over
preferred paths, service providers would like to keep resources preferred paths, service providers would like to keep resources
associated with the working LSPs reserved. This is to make sure that associated with the working LSPs reserved. This is to make sure that
the service can be reverted to the preferred path (working LSP) when the service can be reverted to the preferred path (working LSP) when
the failure is repaired to provide deterministic behavior and the failure is repaired to provide deterministic behavior and
guaranteed Service Level Agreement (SLA). guaranteed Service Level Agreement (SLA).
In this document, we review procedures for GMPLS LSP associations, In this document, we review procedures for GMPLS LSP associations,
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this document. this document.
This document is strictly informative in nature and does not define This document is strictly informative in nature and does not define
any RSVP-TE signaling extensions. any RSVP-TE signaling extensions.
2. Conventions Used in This Document 2. Conventions Used in This Document
2.1. Terminology 2.1. Terminology
The reader is assumed to be familiar with the terminology in The reader is assumed to be familiar with the terminology in
[RFC3209], [RFC3473], [RFC4872], [RFC4873] and [RFC4427]. [RFC3209], [RFC3473], [RFC4872] and [RFC4873]. The terminology for
GMPLS recovery is defined in [RFC4427].
2.2. Acronyms and Abbreviations 2.2. Acronyms and Abbreviations
GMPLS: Generalized Multi-Protocol Label Switching GMPLS: Generalized Multi-Protocol Label Switching
LSP: An MPLS Label Switched Path LSP: An MPLS Label Switched Path
MBB: Make Before Break MBB: Make Before Break
MPLS: Multi-Protocol Label Switching MPLS: Multi-Protocol Label Switching
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signaling techniques. signaling techniques.
3.1.1. 1+R Restoration 3.1.1. 1+R Restoration
One example of the recovery scheme considered in this document is 1+R One example of the recovery scheme considered in this document is 1+R
recovery. The 1+R recovery scheme is exemplified in Figure 1. In recovery. The 1+R recovery scheme is exemplified in Figure 1. In
this example, a working LSP on path A-B-C-Z is pre-established. this example, a working LSP on path A-B-C-Z is pre-established.
Typically after a failure detection and notification on the working Typically after a failure detection and notification on the working
LSP, a second LSP on path A-H-I-J-Z is established as a restoration LSP, a second LSP on path A-H-I-J-Z is established as a restoration
LSP. Unlike a protecting LSP which is set up before the failure, a LSP. Unlike a protecting LSP which is set up before the failure, a
restoration LSP is set up per need basis, after the failure. restoration LSP is set up when needed, after the failure.
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+
| A +----+ B +-----+ C +-----+ Z | | A +----+ B +-----+ C +-----+ Z |
+--+--+ +-----+ +-----+ +--+--+ +--+--+ +-----+ +-----+ +--+--+
\ / \ /
\ / \ /
+--+--+ +-----+ +--+--+ +--+--+ +-----+ +--+--+
| H +-------+ I +--------+ J | | H +-------+ I +--------+ J |
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+
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LSP fails. Two different restoration LSPs may be present, one for LSP fails. Two different restoration LSPs may be present, one for
the working LSP and one for the protecting LSP. the working LSP and one for the protecting LSP.
o Two different restoration LSPs are set up after both working and o Two different restoration LSPs are set up after both working and
protecting LSPs fail, one for the working LSP and one for the protecting LSPs fail, one for the working LSP and one for the
protecting LSP. protecting LSP.
In all these models, if a restoration LSP also fails, it is torn down In all these models, if a restoration LSP also fails, it is torn down
and a new restoration LSP is set up. and a new restoration LSP is set up.
3.2. Resource Sharing By Restoration LSP 3.2. Resource Sharing by Restoration LSP
+-----+ +-----+ +-----+ +-----+
| F +------+ G +--------+ | F +------+ G +--------+
+--+--+ +-----+ | +--+--+ +-----+ |
| | | |
| | | |
+-----+ +-----+ +--+--+ +-----+ +--+--+ +-----+ +-----+ +--+--+ +-----+ +--+--+
| A +----+ B +-----+ C +--X---+ D +-----+ E | | A +----+ B +-----+ C +--X---+ D +-----+ E |
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+
Figure 3: Resource Sharing in 1+R Recovery Scheme Figure 3: Resource Sharing in 1+R Recovery Scheme
Using the network shown in Figure 3 as an example using 1+R recovery Using the network shown in Figure 3 as an example using 1+R recovery
scheme, LSP1 (A-B-C-D-E) is the working LSP, and assume it allows for scheme, LSP1 (A-B-C-D-E) is the working LSP, and assume it allows for
resource sharing when the LSP traffic is dynamically restored. Upon resource sharing when the LSP traffic is dynamically restored. Upon
detecting the failure of a link along the LSP1, e.g. Link C-D, node A detecting the failure of a link along the LSP1, e.g. Link C-D, node A
needs to decide which alternative path it will use to signal needs to decide which alternative path it will use to signal
restoration LSP and reroute traffic. In this case, A-B-C-F-G-E is restoration LSP and reroute traffic. In this case, A-B-C-F-G-E is
chosen as the restoration LSP path and the resources on the path chosen as the restoration LSP path and the resources on the path
segment A-B-C are re-used by this LSP. The working LSP is not torn segment A-B-C are re-used by this LSP. The working LSP is not torn
down and co-exists with the restoration LSP. Nodes A and B down and co-exists with the restoration LSP. When the head-end node
reconfigure the resources to set up the restoration LSP by sending A signals the restoration LSP, nodes C, F, G and E reconfigure the
cross-connection command to the data plane. resources (as listed in Table 1 of this document) to set up the LSP
by sending cross-connection command to the data plane.
In the recovery scheme employing revertive behavior, after the In the recovery scheme employing revertive behavior, after the
failure is repaired, the resources on nodes A and B need to be failure is repaired, the resources on nodes C and E need to be
reconfigured to set up the working LSP. The traffic is then reverted reconfigured to set up the working LSP (using a procedure described
back to the original working LSP. in Section 4.3 of this document) by sending cross-connection command
to the data plane. The traffic is then reverted back to the original
working LSP.
4. RSVP-TE Signaling Procedure 4. RSVP-TE Signaling Procedure
4.1. Restoration LSP Association 4.1. Restoration LSP Association
Where GMPLS end-to-end recovery scheme needs to employ a restoration Where GMPLS end-to-end recovery scheme needs to employ a restoration
LSP while keeping resources for the working and/or protecting LSPs LSP while keeping resources for the working and/or protecting LSPs
reserved in the network after the failure, the restoration LSP is set reserved in the network after the failure, the restoration LSP is set
up with an ASSOCIATION object that has Association Type set to up with an ASSOCIATION object that has Association Type set to
"Recovery" [RFC4872], the Association ID and the Association Source "Recovery" [RFC4872], the Association ID and the Association Source
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4.2. Resource Sharing-based Restoration LSP Setup 4.2. Resource Sharing-based Restoration LSP Setup
GMPLS LSPs can share resources during LSP setup if they have Shared GMPLS LSPs can share resources during LSP setup if they have Shared
Explicit (SE) flag set in the SESSION_ATTRIBUTE objects [RFC3209] in Explicit (SE) flag set in the SESSION_ATTRIBUTE objects [RFC3209] in
the Path messages that create them and: the Path messages that create them and:
o As defined in [RFC3209], LSPs have identical SESSION objects o As defined in [RFC3209], LSPs have identical SESSION objects
and/or and/or
o As defined in [RFC6689], LSPs have matching ASSOCIATION object o As defined in [RFC6689], LSPs have matching ASSOCIATION object
with Association Type set to "Resource Sharing" signaled in their with Association Type set to "Resource Sharing" signaled in their
Path messages. LSPs in this case can have different SESSION Path messages. LSPs in this case can have different SESSION
objects i.e. different Tunnel ID, Source and/or Destination objects i.e. different Tunnel ID, Source and/or Destination
signaled in their Path messages. signaled in their Path messages.
As described in [RFC3209], Section 2.5, the purpose of make-before- As described in [RFC3209], Section 2.5, the purpose of make-before-
break is not to disrupt traffic, or adversely impact network break is not to disrupt traffic, or adversely impact network
operations while TE tunnel rerouting is in progress. In non-packet operations while TE tunnel rerouting is in progress. In non-packet
transport networks during the RSVP-TE signaling procedure, the nodes transport networks during the RSVP-TE signaling procedure, the nodes
set up cross-connections along the LSP accordingly. Because the set up cross-connections along the LSP accordingly. Because the
cross-connection cannot simultaneously connect a shared resource to cross-connection cannot simultaneously connect a shared resource to
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[RFC4427] Mannie, E., and Papadimitriou, D., "Recovery (Protection [RFC4427] Mannie, E., and Papadimitriou, D., "Recovery (Protection
and Restoration) Terminology for Generalized and Restoration) Terminology for Generalized
Multi-Protocol Label Switching", RFC 4427, March 2006. Multi-Protocol Label Switching", RFC 4427, March 2006.
Acknowledgements Acknowledgements
The authors would like to thank George Swallow for the discussions on The authors would like to thank George Swallow for the discussions on
the GMPLS restoration. The authors would like to thank Lou Berger the GMPLS restoration. The authors would like to thank Lou Berger
for the guidance on this work. The authors would also like to thank for the guidance on this work. The authors would also like to thank
Lou Berger, Vishnu Pavan Beeram and Christian Hopps for reviewing Lou Berger, Vishnu Pavan Beeram and Christian Hopps for reviewing
this document and providing valuable comments. this document and providing valuable comments. A special thanks to
Dale Worley for his thorough review of this document.
Contributors Contributors
Gabriele Maria Galimberti Gabriele Maria Galimberti
Cisco Systems, Inc. Cisco Systems, Inc.
EMail: ggalimbe@cisco.com EMail: ggalimbe@cisco.com
Authors' Addresses Authors' Addresses
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