RSVP-TE Signaling For GMPLS Restoration LSP
draft-gandhi-ccamp-gmpls-restoration-lsp-02
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
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|
|---|---|---|---|
| Authors | Rakesh Gandhi , Zafar Ali , Gabriele Galimberti , Xian Zhang | ||
| Last updated | 2014-01-15 | ||
| Replaced by | draft-ietf-ccamp-gmpls-resource-sharing-proc | ||
| RFC stream | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
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draft-gandhi-ccamp-gmpls-restoration-lsp-02
CCAMP Working Group Rakesh Gandhi
Internet-Draft Zafar Ali
Intended status: Informational Gabriele Maria Galimberti
Expires: July 19, 2014 Cisco Systems, Inc.
Xian Zhang
Huawei
January 15, 2014
RSVP-TE Signaling For GMPLS Restoration LSP
draft-gandhi-ccamp-gmpls-restoration-lsp-02
Abstract
In transport networks, there are requirements where Generalized
Multi-Protocol Label Switching (GMPLS) end-to-end recovery scheme
needs to employ restoration LSP while keeping resources for the
working and/or protecting LSPs reserved in the network after the
failure. This draft describes Resource reSerVation Protocol - Traffic
Engineering (RSVP-TE) signaling for GMPLS end-to-end recovery when
using restoration LSP.
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
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material or to cite them other than as "work in progress."
Copyright Notice
Copyright (c) 2014 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
(http://trustee.ietf.org/license-info) in effect on the date of
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publication of this document. Please review these documents
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions used in this document . . . . . . . . . . . . . . 5
3. Restoration LSP Signaling . . . . . . . . . . . . . . . . . . 5
3.1. Signaling Procedure . . . . . . . . . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.1. Normative references . . . . . . . . . . . . . . . . . . . 6
7.2. Informative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
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1. Introduction
Generalized Multi-Protocol Label Switching (GMPLS) extends MPLS to
include support for different switching technologies [RFC3471]
[RFC3473]. These switching technologies provide several protection
schemes [RFC4426][RFC4427] (e.g., 1+1, 1:N and M:N). GMPLS RSVP-TE
signaling has been extended to support various recovery schemes to
establish Label Switched Paths (LSPs) [RFC4872][RFC4873], typically
working LSP and protecting LSP. [RFC4427] Section 7 specifies various
schemes for GMPLS restoration.
In GMPLS recovery schemes generally considered, restoration LSP is
signaled after the failure has been detected and notified on the
working LSP. In non-revertive recovery mode, working LSP is assumed
to be removed from the network before restoration LSP is signaled.
For revertive recovery mode, a restoration LSP is signaled while
working LSP and/or protecting LSP are not torn down in control plane
due to a failure. In transport networks, as working LSPs are
typically signaled over a nominal path, service providers would like
to keep resources associated with the working LSPs reserved. This is
to make sure that the service (working LSP) can use the nominal path
when the failure is repaired. Consequently, revertive recovery mode
is usually preferred by recovery schemes used in transport networks.
As defined in [RFC4872] and being considered in this draft, "fully
dynamic rerouting switches normal traffic to an alternate LSP that is
not even partially established only after the working LSP failure
occurs. The new alternate route is selected at the LSP head-end node,
it may reuse resources of the failed LSP at intermediate nodes and
may include additional intermediate nodes and/or links."
One example of the recovery scheme considered in this draft is 1+R
recovery. The 1+R recovery is exemplified in Figure 1. In this
example, working LSP on path A-B-C-Z is pre-established. 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.
Unlike protection LSP, restoration LSP is signaled per need basis.
A --- B --- C --- Z
\ /
H --- I --- J
Figure 1: An example of 1+R recovery scheme
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During failure switchover with 1+R recovery scheme, in general,
working LSP resources are not released and working and restoration
LSPs coexist in the network. Nonetheless, working and restoration
LSPs can share network resources. Typically when failure is recovered
on the working LSP, restoration LSP is no longer required and torn
down (e.g., revertive mode).
Another example of the recovery scheme considered in this draft is
1+1+R. In 1+1+R, a restoration LSP is signaled for the working LSP
and/or the protecting LSP after the failure has been detected and
notified on the working LSP or the protecting LSP. The 1+1+R recovery
is exemplified in Figure 2. In this example, working LSP on path A-B-
C-Z and protecting LSP on path A-D-E-F-Z are pre-established. After a
failure detection and notification on a working LSP or protecting
LSP, a third LSP on path A-H-I-J-Z is established as a restoration
LSP. The restoration LSP in this case provides protection against a
second order failure. Restoration LSP is torn down when the failure
on the working or protecting LSP is repaired.
D --- E --- F
/ \
A --- B --- C --- Z
\ /
H --- I --- J
Figure 2: An example of 1+1+R recovery scheme
[RFC4872] Section 14 defines PROTECTION object for GMPLS recovery
signaling. The PROTECTION object is used to identify primary and
secondary LSPs using S bit and protecting and working LSPs using P
bit. [RFC4872] and [RFC6689] define the usage of ASSOCIATION object
for further associating GMPLS working and protecting LSPs. However,
these existing methods do not specify how to identify restoration LSP
when working/protecting LSPs are not torn down.
This draft describes procedures for identifying the restoration LSP
for GMPLS end-to-end recovery where working and protecting LSP
resources are kept reserved after the failure.
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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 [RFC2119].
3. Restoration LSP Signaling
3.1. Signaling Procedure
Where GMPLS recovery scheme needs to employ restoration LSP while
keeping resources for the working and/or protecting LSPs reserved in
the network, restoration LSP is signaled with ASSOCIATION object with
the association ID set to the LSP ID of the LSP it is restoring. For
example, when a restoration LSP is signaled for a working LSP, the
ASSOCIATION object in the restoration LSP contains the association ID
set to the LSP ID of the working LSP. Similarly, when a restoration
LSP is signaled for a protecting LSP, the ASSOCIATION object in the
restoration LSP contains the association ID set to the LSP ID of the
protecting LSP.
The procedure for signaling the PROTECTION object is specified in
[RFC4872] and is changed by this document. Restoration LSP being used
as a working LSP is signaled with P bit cleared and as a protecting
LSP is signaled with P bit set.
When using a GMPLS recovery mode, where the restoration LSP is
promoted to be the new working LSP, restoration LSP RSVP Path message
MUST be refreshed by using the ASSOCIATION_OBJECT.LSP_ID to contain
the LSP ID of the protecting LSP if known or LSP ID of itself if
protecting LSP is not known as defined in [RFC6689].
When using a GMPLS recovery mode, where the restoration LSP is
promoted to be the new protecting LSP, restoration LSP RSVP Path
message MUST be refreshed by using the ASSOCIATIN_OBJECT.LSP_ID to
contain the LSP ID of the working LSP if known or LSP ID of itself if
working LSP is not known as defined in [RFC6689].
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4. IANA Considerations
This document makes no request for IANA action.
5. Security Considerations
This document introduces no additional security considerations. For a
general discussion on MPLS and GMPLS related security issues, see the
MPLS/GMPLS security framework [RFC5920]. In addition, the
considerations specified in [RFC4872] will apply.
6. Acknowledgement
The authors would like to thank George Swallow for the discussion on
the GMPLS restoration.
7. References
7.1. Normative references
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, September 1997.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.
[RFC3471] Berger, L., Editor, "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Functional Description", RFC
3471, January 2003.
[RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Resource ReserVation Protocol-Traffic
Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.
[RFC4872] Lang, J., Rekhter, Y., and D. Papadimitriou, "RSVP-TE
Extensions in Support of End-to-End Generalized Multi-
Protocol Label Switching (GMPLS) Recovery", RFC 4872, May
2007.
[RFC4873] Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel,
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"GMPLS Segment Recovery", RFC 4873, May 2007.
[RFC6689] Berger, L, "Usage of the RSVP ASSOCIATION Object", RFC
6689, July 2012.
7.2. Informative References
[RFC4426] Lang, J., Rajagopalan B., and D.Papadimitriou, Editors,
"Generalized Multiprotocol Label Switching (GMPLS)
Recovery Functional Specification", RFC 4426, March 2006.
[RFC4427] Mannie, E., Ed. and D. Papadimitriou, Ed., "Recovery
(Protection and Restoration) Terminology for Generalized
Multi-Protocol Label Switching, RFC 4427, March 2006.
[RFC5920] Fang, L., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, July 2010.
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Authors' Addresses
Rakesh Gandhi
Cisco Systems, Inc.
Email: rgandhi@cisco.com
Zafar Ali
Cisco Systems, Inc.
Email: zali@cisco.com
Gabriele Maria Galimberti
Cisco Systems, Inc.
Email: ggalimbe@cisco.com
Xian Zhang
Huawei Technologies
Research Area F3-1B,
Huawei Industrial Base,
Shenzhen, 518129, China
Email: zhang.xian@huawei.com
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