Internet DRAFT - draft-ietf-pce-remote-initiated-gmpls-lsp
draft-ietf-pce-remote-initiated-gmpls-lsp
PCE Working Group Z. Ali
Internet-Draft S. Sivabalan
Intended status: Standards Track C. Filsfils
Expires: August 27, 2019 Cisco Systems
R. Varga
Pantheon Technologies
V. Lopez
O. Gonzalez de Dios
Telefonica
H. Zheng
X. Zhang
Huawei Technologies
February 23, 2019
Path Computation Element Communication Protocol (PCEP) Extensions for
remote-initiated GMPLS LSP Setup
draft-ietf-pce-remote-initiated-gmpls-lsp-06.txt
Abstract
[RFC8281] specifies procedures that can be used for creation and
deletion of PCE-initiated LSPs in the active stateful PCE model.
However, this specification focuses on MPLS networks, and does not
cover remote instantiation of paths in GMPLS-controlled networks.
This document complements [RFC8281] by addressing the requirements
for remote-initiated GMPLS LSPs.
Requirements Language
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].
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
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
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This Internet-Draft will expire on August 27, 2019.
Copyright Notice
Copyright (c) 2019 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
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements for Remote-Initiated GMPLS LSPs . . . . . . . . 3
3. PCEP Extensions for Remote-Initiated GMPLS LSPs . . . . . . . 4
3.1. Generalized Endpoint in LSP Initiate Message . . . . . . . 4
3.2. GENERALIZED-BANDWIDTH object in LSP Initiate Message . . . 4
3.3. Protection Attributes in LSP Initiate Message . . . . . . . 5
3.4. ERO in LSP Initiate Object . . . . . . . . . . . . . . . . 5
3.4.1. ERO with explicit label control . . . . . . . . . . . . . 5
3.4.2. ERO with Path Keys . . . . . . . . . . . . . . . . . . . 6
3.4.3. Switch Layer Object . . . . . . . . . . . . . . . . . . . 6
3.5. LSP delegation and cleanup . . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
5.1. PCEP-Error Object . . . . . . . . . . . . . . . . . . . . . 7
6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . . 7
8.2. Informational References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
The Path Computation Element communication Protocol (PCEP) provides
mechanisms for Path Computation Elements (PCEs) to perform route
computations in response to Path Computation Clients (PCCs) requests.
PCEP Extensions for PCE-initiated LSP Setup in a Stateful PCE Model
draft [RFC8231] describes a set of extensions to PCEP to enable
active control of MPLS-TE and GMPLS network.
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[RFC8281] describes the setup and teardown of PCE-initiated LSPs
under the active stateful PCE model, without the need for local
configuration on the PCC. This enables realization of a dynamic
network that is centrally controlled and deployed. However, this
specification is focused on MPLS networks, and does not cover the
GMPLS networks (e.g., WSON, OTN, SONET/ SDH, etc. technologies).
This document complements [RFC8281] by addressing the requirements
for remote-initiated GMPLS LSPs. These requirements are covered in
Section 2 of this draft. The PCEP extensions for remote initiated
GMPLS LSPs are specified in Section 3.
2. Requirements for Remote-Initiated GMPLS LSPs
[RFC8281] specifies procedures that can be used for creation and
deletion of PCE-initiated LSPs under the active stateful PCE model.
However, this specification does not address GMPLS requirements
outlined in the following:
o GMPLS support multiple switching capabilities on per TE link
basis. GMPLS LSP creation requires knowledge of LSP switching
capability (e.g., TDM, L2SC, OTN-TDM, LSC, etc.) to be used
[RFC3471] , [RFC3473] .
o GMPLS LSP creation requires knowledge of the encoding type (e.g.,
lambda photonic, Ethernet, SONET/ SDH, G709 OTN, etc.) to be used
by the LSP [RFC3471] , [RFC3473].
o GMPLS LSP creation requires information of the generalized payload
(G-PID) to be carried by the LSP [RFC3471] , [RFC3473].
o GMPLS LSP creation requires specification of data flow specific
traffic parameters (also known as Tspec), which are technology
specific.
o GMPLS also specifics support for asymmetric bandwidth requests
[RFC6387] .
o GMPLS extends the addressing to include unnumbered interface
identifiers, as defined in [RFC3477] .
o In some technologies path calculation is tightly coupled with
label selection along the route. For example, path calculation in
a WDM network may include lambda continuity and/ or lambda
feasibility constraints and hence a path computed by the PCE is
associated with a specific lambda (label). Hence, in such
networks, the label information needs to be provided to a PCC in
order for a PCE to initiate GMPLS LSPs under the active stateful
PCE model. I.e., explicit label control may be required.
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o GMPLS specifics protection context for the LSP, as defined in
[RFC4872] , [RFC4873].
3. PCEP Extensions for Remote-Initiated GMPLS LSPs
LSP initiate (PCInitiate) message defined in [RFC8281] needs to be
extended to include GMPLS specific PCEP objects as follows:
3.1. Generalized Endpoint in LSP Initiate Message
This document does not modify the usage of END-POINTS object for PCE
initiated LSPs as specified in [RFC8281] . It augments the usage as
specified below.
END-POINTS object has been extended by
[I-D.ietf-pce-gmpls-pcep-extensions] to include a new object type
called "Generalized Endpoint". PCInitiate message sent by a PCE to a
PCC to trigger a GMPLS LSP instantiation SHOULD include the END-
POINTS with Generalized Endpoint object type. Furthermore, the END-
POINTS object MUST contain "label request" TLV. The label request
TLV is used to specify the switching type, encoding type and GPID of
the LSP being instantiated by the PCE.
If the END-POINTS Object of type Generalized Endpoint is missing the
label request TLV, the PCC MUST send a PCErr message with Error-
type=6 (Mandatory Object missing) and Error-value= TBA (label request
TLV missing).
If the PCC does not support the END-POINTS Object of type Generalized
Endpoint, the PCC MUST send a PCErr message with Error-type = 3
(Unknown Object), Error-value = 2(unknown object type).
The unnumbered endpoint TLV can be used to specify unnumbered
endpoint addresses for the LSP being instantiated by the PCE. The
END-POINTS MAY contain other TLVs defined in
[I-D.ietf-pce-gmpls-pcep-extensions].
3.2. GENERALIZED-BANDWIDTH object in LSP Initiate Message
LSP initiate message defined in [RFC8281] can optionally include the
BANDWIDTH object. However, the following possibilities cannot be
represented in the BANDWIDTH object:
o Asymmetric bandwidth (different bandwidth in forward and reverse
direction), as described in [RFC6387] .
o Technology specific GMPLS parameters (e.g., Tspec for SDH/SONET,
G.709, ATM, MEF, etc.) are not supported.
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GENERALIZED-BANDWIDTH object has been defined in
[I-D.ietf-pce-gmpls-pcep-extensions] to address the above-mentioned
limitation of the BANDWIDTH object.
This document specifies the use of GENERALIZED-BANDWIDTH object in
PCInitiate message. Specifically, GENERALIZED-BANDWIDTHobject MAY be
included in the PCInitiate message. The GENERALIZED-BANDWIDTH object
in PCInitiate message is used to specify technology specific Tspec
and asymmetrical bandwidth values for the LSP being instantiated by
the PCE.
3.3. Protection Attributes in LSP Initiate Message
This document does not modify the usage of LSPA object for PCE
initiated LSPs as specified in [RFC8281] . It augments the usage of
LSPA object in LSP Initiate Message to carry the end-to-end
protection context this also includes the protection state
information.
The LSP Protection Information TLV of LSPA in the PCInitiate message
can be used to specify protection attributes of the LSP being
instantiated by the PCE.
3.4. ERO in LSP Initiate Object
This document does not modify the usage of ERO object for PCE
initiated LSPs as specified in [RFC8281]. It augments the usage as
specified in the following sections.
3.4.1. ERO with explicit label control
As mentioned earlier, there are technologies and scenarios where
active stateful PCE requires explicit label control in order to
instantiate an LSP.
Explicit label control (ELC) is a procedure supported by RSVP-TE,
where the outgoing label(s) is (are) encoded in the ERO.
[I-D.ietf-pce-gmpls-pcep-extensions] extends the ERO object of PCEP
to include explicit label control. The ELC procedure enables the PCE
to provide such label(s) directly in the path ERO.
The extended ERO object in PCInitiate message can be used to specify
label along with ERO to PCC for the LSP being instantiated by the
active stateful PCE.
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3.4.2. ERO with Path Keys
There are many scenarios in packet and optical networks where the
route information of an LSP may not be provided to the PCC for
confidentiality reasons. A multi-domain or multi-layer network is an
example of such networks. Similarly, a GMPLS User- Network Interface
(UNI) [RFC4208] is also an example of such networks.
In such scenarios, ERO containing the entire route cannot be provided
to PCC (by PCE). Instead, PCE provides an ERO with Path Keys to the
PCC. For example, in the case UNI interface between the router and
the optical nodes, the ERO in the LSP Initiate Message may be
constructed as follows:
o The first hop is a strict hop that provides the egress interface
information at PCC. This interface information is used to get to
a network node that can extend the rest of the ERO. (Please note
that in the cases where the network node is not directly connected
with the PCC, this part of ERO may consist of multiple hops and
may be loose).
o The following(s) hop in the ERO may provide the network node with
the path key [RFC5520] that can be resolved to get the contents of
the route towards the destination.
o There may be further hops but these hops may also be encoded with
the path keys (if needed).
This document does not change encoding or processing roles for the
path keys, which are defined in [RFC5520].
3.4.3. Switch Layer Object
[I-D.ietf-pce-inter-layer-ext] specifies the SWITCH-LAYER object
which defines and specifies the switching layer (or layers) in which
a path MUST or MUST NOT be established. A switching layer is
expressed as a switching type and encoding type.
[I-D.ietf-pce-gmpls-pcep-extensions], which defines the GMPLS
extensions for PCEP, suggests using the SWITCH-LAYER object. Thus,
SWITCH-LAYER object can be used in the PCInitiate message to specify
the switching layer (or layers) of the LSP being remotely initiated.
3.5. LSP delegation and cleanup
LSP delegation and cleanup procedure specified in
[I-D.ietf-pce-gmpls-pcep-extensions] are equally applicable to GMPLS
LSPs and this document does not modify the associated usage.
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4. Security Considerations
The security considerations described in [RFC8281] apply to the
extensions described in this document.
5. IANA Considerations
5.1. PCEP-Error Object
This document defines the following new Error-Value:
Error-type Error Value Reference
6 Error-value = TBA: Label Request TLV Missing this document
6. Contributors
Sajal Agarwal
Cisco Systems
Email: sajaagar@cisco.com
7. Acknowledgements
The authors would like to thank George Swallow and Jan Medved for
their comments.
8. References
8.1. Normative References
[I-D.ietf-pce-gmpls-pcep-extensions]
Margaria, C., Dios, O., and F. Zhang, "PCEP extensions for
GMPLS", draft-ietf-pce-gmpls-pcep-extensions-13 (work in
progress), January 2019.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009,
<https://www.rfc-editor.org/info/rfc5440>.
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[RFC5623] Oki, E., Takeda, T., Le Roux, JL., and A. Farrel,
"Framework for PCE-Based Inter-Layer MPLS and GMPLS
Traffic Engineering", RFC 5623, DOI 10.17487/RFC5623,
September 2009, <https://www.rfc-editor.org/info/rfc5623>.
[RFC6107] Shiomoto, K., Ed. and A. Farrel, Ed., "Procedures for
Dynamically Signaled Hierarchical Label Switched Paths",
RFC 6107, DOI 10.17487/RFC6107, February 2011,
<https://www.rfc-editor.org/info/rfc6107>.
[RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
Computation Element Communication Protocol (PCEP)
Extensions for Stateful PCE", RFC 8231,
DOI 10.17487/RFC8231, September 2017,
<https://www.rfc-editor.org/info/rfc8231>.
[RFC8281] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path
Computation Element Communication Protocol (PCEP)
Extensions for PCE-Initiated LSP Setup in a Stateful PCE
Model", RFC 8281, DOI 10.17487/RFC8281, December 2017,
<https://www.rfc-editor.org/info/rfc8281>.
8.2. Informational References
[I-D.ietf-pce-inter-layer-ext]
Oki, E., Takeda, T., Farrel, A., and F. Zhang, "Extensions
to the Path Computation Element communication Protocol
(PCEP) for Inter-Layer MPLS and GMPLS Traffic
Engineering", draft-ietf-pce-inter-layer-ext-12 (work in
progress), January 2017.
[RFC3471] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Functional Description",
RFC 3471, DOI 10.17487/RFC3471, January 2003,
<https://www.rfc-editor.org/info/rfc3471>.
[RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
DOI 10.17487/RFC3473, January 2003,
<https://www.rfc-editor.org/info/rfc3473>.
[RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links
in Resource ReSerVation Protocol - Traffic Engineering
(RSVP-TE)", RFC 3477, DOI 10.17487/RFC3477, January 2003,
<https://www.rfc-editor.org/info/rfc3477>.
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[RFC4208] Swallow, G., Drake, J., Ishimatsu, H., and Y. Rekhter,
"Generalized Multiprotocol Label Switching (GMPLS) User-
Network Interface (UNI): Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE) Support for the Overlay
Model", RFC 4208, DOI 10.17487/RFC4208, October 2005,
<https://www.rfc-editor.org/info/rfc4208>.
[RFC4872] Lang, J., Ed., Rekhter, Y., Ed., and D. Papadimitriou,
Ed., "RSVP-TE Extensions in Support of End-to-End
Generalized Multi-Protocol Label Switching (GMPLS)
Recovery", RFC 4872, DOI 10.17487/RFC4872, May 2007,
<https://www.rfc-editor.org/info/rfc4872>.
[RFC4873] Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel,
"GMPLS Segment Recovery", RFC 4873, DOI 10.17487/RFC4873,
May 2007, <https://www.rfc-editor.org/info/rfc4873>.
[RFC5520] Bradford, R., Ed., Vasseur, JP., and A. Farrel,
"Preserving Topology Confidentiality in Inter-Domain Path
Computation Using a Path-Key-Based Mechanism", RFC 5520,
DOI 10.17487/RFC5520, April 2009,
<https://www.rfc-editor.org/info/rfc5520>.
[RFC6387] Takacs, A., Berger, L., Caviglia, D., Fedyk, D., and J.
Meuric, "GMPLS Asymmetric Bandwidth Bidirectional Label
Switched Paths (LSPs)", RFC 6387, DOI 10.17487/RFC6387,
September 2011, <https://www.rfc-editor.org/info/rfc6387>.
Authors' Addresses
Zafar Ali
Cisco Systems
Email: zali@cisco.com
Siva Sivabalan
Cisco Systems
Email: msiva@cisco.com
Clarence Filsfils
Cisco Systems
Email: cfilsfil@cisco.com
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Robert Varga
Pantheon Technologies
Email: nite@hq.sk
Victor Lopez
Telefonica
Email: victor.lopezalvarez@telefonica.com
Oscar Gonzalez de Dios
Telefonica
Email: oscar.gonzalezdedios@telefonica.com
Haomian Zheng (Editor)
Huawei Technologies
H1-1-A043S Huawei Industrial Base, Songshanhu
Dongguan, Guangdong 523808
P.R.China
Email: zhenghaomian@huawei.com
Xian Zhang
Huawei Technologies
G1-2, Huawei Industrial Base, Bantian, Longgang District
Shenzhen, Guangdong 518129
P.R.China
Email: zhang.xian@huawei.com
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