LSP Object Flag Extension of Stateful PCE
draft-ietf-pce-lsp-extended-flags-00
PCE Q. Xiong
Internet-Draft ZTE Corporation
Intended status: Standards Track March 8, 2021
Expires: September 9, 2021
LSP Object Flag Extension of Stateful PCE
draft-ietf-pce-lsp-extended-flags-00
Abstract
RFC 8231 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, 11 bits of the Flag field have already been assigned
in RFC 8231, RFC 8281 and RFC 8623.
This document proposes to define a new LSP-EXTENDED-FLAG TLV for the
LSP object for an extended flag field.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on September 9, 2021.
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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 . . . . . . . . . . . . . . 4
5.1.2. LSP Extended Flags Field . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 5
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
9.1. Normative References . . . . . . . . . . . . . . . . . . 5
9.2. Informative References . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
[RFC5440] describes the Path Computation Element Protocol (PCEP)
which is used between a Path Computation Element (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
(P2MP) respectively. Almost all bits of the Flag field has been
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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=TBD | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// LSP Extended Flags //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: LSP-EXTENDED-FLAG TLV Format
Type (16 bits): the value is TBD1 by IANA.
Length (16 bits): multiple of 4 octets.
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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 operation, feature, or state. Currently no bits
are assigned. Unassigned bits MUST be set to zero on transmission
and MUST be ignored on receipt.
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.
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
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]
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:
o Bit number (counting from bit 0 as the most significant bit)
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o Capability description
o Defining RFC
No values are currently defined.
6. 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.
7. Acknowledgements
The authors would like to thank Loa Andersson and Adrian Farrel for
their review, suggestions and comments to this document.
8. Contributors
The following people have contributed to this document:
Dhruv Dhody
EMail: dhruv.ietf@gmail.com
9. References
9.1. 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>.
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[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>.
9.2. Informative References
[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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