LSP Object Flag Extension of Stateful PCE
draft-ietf-pce-lsp-extended-flags-02
| Document | Type | Active Internet-Draft (pce WG) | |
|---|---|---|---|
| Author | Quan Xiong | ||
| Last updated | 2022-05-11 | ||
| Replaces | draft-xiong-pce-lsp-flag | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | (None) | ||
| Formats | plain text html xml htmlized pdfized bibtex | ||
| Stream | WG state | In WG Last Call | |
| Document shepherd | (None) | ||
| IESG | IESG state | I-D Exists | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-pce-lsp-extended-flags-02
PCE Q. Xiong
Internet-Draft ZTE Corporation
Intended status: Standards Track May 2022
Expires: 9 November 2022
LSP Object Flag Extension of Stateful PCE
draft-ietf-pce-lsp-extended-flags-02
Abstract
[RFC8231] describes a set of extensions to Path Computation Element
Communication Protocol (PCEP) to enable stateful control of MPLS-TE
and GMPLS Label Switched Paths (LSPs) via PCEP. One of the
extensions is the LSP object which includes a Flag field of the
length of 12 bits. However, all bits of the Flag field have already
been assigned in [RFC8231], [RFC8281], [RFC8623] and
[I-D.ietf-pce-binding-label-sid].
This document proposes to define a new LSP-EXTENDED-FLAG TLV for the
LSP object for an extended flag field.
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."
This Internet-Draft will expire on 2 November 2022.
Copyright Notice
Copyright (c) 2022 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 (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
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and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 3
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Requirements Language . . . . . . . . . . . . . . . . . . 3
3. PCEP Extension . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. The LSP-EXTENDED-FLAG TLV . . . . . . . . . . . . . . . . 3
3.2. Processing . . . . . . . . . . . . . . . . . . . . . . . 4
4. Backward Compatibility . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5.1. LSP Object . . . . . . . . . . . . . . . . . . . . . . . 4
5.1.1. PCEP TLV Type Indicators . . . . . . . . . . . . . . 5
5.1.2. LSP Extended Flags Field . . . . . . . . . . . . . . 5
6. Implementation Status . . . . . . . . . . . . . . . . . . . . 5
7. Security Considerations . . . . . . . . . . . . . . . . . . . 6
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 6
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
10.1. Normative References . . . . . . . . . . . . . . . . . . 7
10.2. Informative References . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
[RFC5440] describes the Path Computation Element (PCE) Communication
Protocol (PCEP) which is used between a PCE and a Path Computation
Client (PCC) (or other PCE) to enable computation of Multi-protocol
Label Switching (MPLS) for Traffic Engineering Label Switched Path
(TE LSP).
PCEP Extensions for the Stateful PCE Model [RFC8231] describes a set
of extensions to PCEP to enable active control of MPLS-TE and
Generalized MPLS (GMPLS) tunnels. One of the extensions is the LSP
object which contains a flag field; bits in the flag field are used
to indicate delegation, syncronization, removal, etc.
As defined in [RFC8231], the length of the flag field is 12 bits and
the value from bit 5 to bit 11 is used for operational,
administrative, remove, synchronize and delegate bits respectively.
The bit value 4 is assigned in [RFC8281] for create for PCE-Initiated
LSPs. The bits from 1 to 3 is assigned in [RFC8623] for Explicit
Route Object (ERO)-compression, fragmentation and Point-to-Multipoint
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(P2MP) respectively. The bit 0 is assigned in
[I-D.ietf-pce-binding-label-sid] to PCE-allocation. All bits of the
Flag field has been assigned already. Thus, it is required to extend
the flag field for the LSP Object for future use.
This document proposes to define a new LSP-EXTENDED-FLAG TLV for an
extended flag field in the LSP object.
2. Conventions used in this document
2.1. Terminology
The terminology is defined as [RFC5440] and [RFC8231].
2.2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. PCEP Extension
The LSP Object is defined in Section 7.3 of [RFC8231]. This document
proposes to define a new LSP-EXTENDED-FLAG TLV for an extended flag
field in the LSP object.
3.1. The LSP-EXTENDED-FLAG TLV
The format of the LSP-EXTENDED-FLAG TLV is as shown in the Figure 1.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=TBD1 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// LSP Extended Flags //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Figure 1: LSP-EXTENDED-FLAG TLV Format
Type (16 bits): the value is TBD1 by IANA.
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Length (16 bits): multiple of 4 octets.
LSP Extended Flags: this contains an array of units of 32-bit flags
numbered from the most significant as bit zero, where each bit
represents one LSP flag (for operation, feature, or state).
Currently no bits are assigned. Unassigned bits MUST be set to zero
on transmission and MUST be ignored on receipt. For example of usage
of the LSP-EXTENDED-FLAG TLV, the E-flag is requested for entropy
label configuration proposed in
[I-D.peng-pce-entropy-label-position].
3.2. Processing
The LSP Extended Flags field is an array of units of 32 flags and to
be allocated starting from the most significant bit. No bits are
currently assigned in this document and the bits of the LSP Extended
Flags field will be assigned by future documents.
Note that, PCEP peers MAY encounter different length of the LSP-
EXTENDED-FLAG TLV.
If a PCEP speaker receives the LSP-EXTENDED-FLAG TLV of a length more
than it currently supports or understands, it will simply ignore the
bits beyond that length.
If a PCEP speaker receives the LSP-EXTENDED-FLAG TLV of a length less
than the one supported by the implementation, it will consider the
bits beyond the length to be unset.
4. Backward Compatibility
The LSP-EXTENDED-FLAG TLV defined in this document does not introduce
any interoperability issues.
A router that does not understand or support the LSP-EXTENDED-FLAG
TLV will silently ignore the TLV as per [RFC5440]. It is expected
that future document that define bits in the LSP-EXTENDED-FLAG TLV
would also define the error case handling required for missing LSP-
EXTENDED-FLAG TLV.
5. IANA Considerations
5.1. LSP Object
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5.1.1. PCEP TLV Type Indicators
IANA is requested to allocate the following TLV Type Indicator value
within the "PCEP TLV Type Indicators" subregistry of the "Path
Computation Element Protocol (PCEP) Numbers" registry:
+=======+===================+=================+
| Value | Description | Reference |
+=======+===================+=================+
| TBD1 | LSP-EXTENDED-FLAG | [This document] |
+-------+-------------------+-----------------+
Table 1
5.1.2. LSP Extended Flags Field
IANA is requested to create a new subregistry called "LSP-EXTENDED-
FLAG TLV Flag Field", within the "Path Computation Element Protocol
(PCEP) Numbers" registry to manage the LSP Extended Flags field of
the LSP-EXTENDED-FLAG TLV. New values are assigned by Standards
Action [RFC8126]. Each bit should be tracked with the following
qualities:
* Bit number (counting from bit 0 as the most significant bit)
* Capability description
* Defining RFC
No values are currently defined.
6. Implementation Status
[NOTE TO RFC EDITOR : This whole section and the reference to
[RFC7942] is to be removed before publication as an RFC]
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This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in [RFC7942].
The description of implementations in this section is intended to
assist the IETF in its decision processes in progressing drafts to
RFCs. Please note that the listing of any individual implementation
here does not imply endorsement by the IETF. Furthermore, no effort
has been spent to verify the information presented here that was
supplied by IETF contributors. This is not intended as, and must not
be construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may
exist.
According to [RFC7942], "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature.
It is up to the individual working groups to use this information as
they see fit".
At the time of posting this version of this document, there are no
known implementations of this TLV. It is believed that this would be
implemented along side the documents that allocate flags in the TLV.
7. Security Considerations
For LSP Object procssing security considerations, see [RFC8231].
No additional security issues are raised in this document beyond
those that exist in the referenced documents.
8. Acknowledgements
The authors would like to thank Loa Andersson and Adrian Farrel for
their review, suggestions and comments to this document.
9. Contributors
The following people have substantially contributed to this document:
Dhruv Dhody
Huawei Technologies
EMail: dhruv.ietf@gmail.com
Greg Mirsky
Ericsson
Email: gregimirsky@gmail.com
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10. References
10.1. Normative References
[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>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[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>.
10.2. Informative References
[I-D.ietf-pce-binding-label-sid]
Sivabalan, S., Filsfils, C., Tantsura, J., Previdi, S.,
and C. L. (editor), "Carrying Binding Label/Segment
Identifier (SID) in PCE-based Networks.", Work in
Progress, Internet-Draft, draft-ietf-pce-binding-label-
sid-15, 20 March 2022, <https://www.ietf.org/archive/id/
draft-ietf-pce-binding-label-sid-15.txt>.
[I-D.peng-pce-entropy-label-position]
Xiong, Q., Peng, S., and F. Qin, "PCEP Extension for SR-
MPLS Entropy Label Position", Work in Progress, Internet-
Draft, draft-peng-pce-entropy-label-position-07, 2 March
2022, <https://www.ietf.org/archive/id/draft-peng-pce-
entropy-label-position-07.txt>.
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[RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", BCP 205,
RFC 7942, DOI 10.17487/RFC7942, July 2016,
<https://www.rfc-editor.org/info/rfc7942>.
[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>.
[RFC8623] Palle, U., Dhody, D., Tanaka, Y., and V. Beeram, "Stateful
Path Computation Element (PCE) Protocol Extensions for
Usage with Point-to-Multipoint TE Label Switched Paths
(LSPs)", RFC 8623, DOI 10.17487/RFC8623, June 2019,
<https://www.rfc-editor.org/info/rfc8623>.
Author's Address
Quan Xiong
ZTE Corporation
No.6 Huashi Park Rd
Wuhan
Hubei, 430223
China
Email: xiong.quan@zte.com.cn
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