Internet DRAFT - draft-hu-pce-stitching-lsp-association
draft-hu-pce-stitching-lsp-association
PCE Quan Xiong
Internet-Draft Greg Mirsky
Intended status: Standards Track ZTE Corporation
Expires: April 24, 2020 Fangwei Hu
Individual
Weiqiang Cheng
China Mobile
October 22, 2019
Stitching LSP Association
draft-hu-pce-stitching-lsp-association-02
Abstract
The Path Computation Element Communication Protocol (PCEP) provides
mechanisms for Path Computation Elements (PCEs) to perform path
computations in response to Path Computation Clients (PCCs) requests.
[I-D.ietf-pce-association-group] proposed an association mechanism
for a set of LSPs.
This document defines the stitching LSP association type and
stitching LSP association TLV for the inter-domain scenairo.
Status of This Memo
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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
Provisions Relating to IETF Documents
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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. Stitching LSPs in SR-MPLS Inter-domain Scenario . . . . . . . 3
4. PCEP Extension for Stitching LSP . . . . . . . . . . . . . . 3
4.1. I-flag in LSP Object . . . . . . . . . . . . . . . . . . 3
4.2. Stitching LSP Association Type and Group . . . . . . . . 4
4.3. Stitching LSP Association TLV . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7.1. New LSP Flag Registry . . . . . . . . . . . . . . . . . . 5
7.2. Association Object Type . . . . . . . . . . . . . . . . . 6
8. Normative References . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
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). [I-D.ietf-pce-association-group] proposed an
association mechanism to create a grouping of LSPs in the context of
a PCE.
[I-D.xiong-pce-stateful-pce-sr-inter-domain] introduces the procedure
and the PCEP extension to form the inter-domain MPLS data entries and
the multiple LSPs from multiple contiguous domains need to be
stitched to an end-to-end LSP in SR inter-domain scenario.
This document proposes a new association object type called
"stitching Association LSP type" and TLV called "Stitching LSP
Association TLV" to associate a grouping of LSPs from multiple
domains for inter-domain scenario.
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2. Conventions used in this document
2.1. Terminology
The terminology is defined as [RFC5440],
[I-D.ietf-pce-association-group] and
[I-D.xiong-pce-stateful-pce-sr-inter-domain].
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. Stitching LSPs in SR-MPLS Inter-domain Scenario
As described in [I-D.xiong-pce-stateful-pce-sr-inter-domain], the
domains of the networks may be IGP Areas in stitching inter-domain
scenario. As Figure 1 shown, the multiple SR-MPLS domains may be
interconnect with a ABR within areas. The multiple LSPs in each
domain can be stitched to an inter-domain end-to-end LSP. The LSP-1,
LSP-2 and LSP-3 can be associated to a group.
.................. ................. ....................
. . . . . .
+-----+ +-----+ +-----+ +-----+
| A | | X | | Y | | Z |
+-----+ +-----+ +-----+ +-----+
. IGP-1 . . IGP-2 . . IGP-3 .
.................. ................. ...................
|--------LSP-1------>|-------LSP-2------->|-------LSP-3------->|
|--------------Stitching LSP Association Group---------------->|
Figure 1: Stitching LSPs in SR-MPLS Inter-domain Scenario
4. PCEP Extension for Stitching LSP
4.1. I-flag in LSP Object
The LSP Object is defined in Section 7.3 of [RFC8231]. This document
defiend a new flag (I-flag) for the LSP Object as Figure 2 shown:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PLSP-ID | Flag|I|C| O |A|R|S|D|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// TLVs //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: I-flag in LSP Object
I (Request for Inter-domain Path) : If the bit is set to 1, it
indicates that the PCC requests PCE to compute the end-to-end path
for inter-domain scenario carried in PCReq message. A parent PCE
would set this bit to 1 to indicate that it is an end-to-end inter-
domain path and a chid PCE would set it to 1 to indicate that the
path is part of an end-to-end inter-domain path. That may be encoded
in the PCRep, PCUpd or PCInitiate message.
4.2. Stitching LSP Association Type and Group
An association ID will be used to identify the group and a new
Association Type is defined in this document, based on the generic
Association object :
Association Type (TBD) = Stitching LSP Association Group (SLAG).
SLAG may carry optional TLVs including but not limited to :
STITCHING-LSP-ASSOCIATION-TLV: Used to identify the role of stitching
LSPs, described in Section 4.3.
As [I-D.ietf-pce-association-group] specified, the capability
advertisement of the association types supported by a PCEP speaker is
performed by defining a ASSOC-Type-List TLV to be carried within an
OPEN object. The association type which defined in this document
should be added in the list and be advertised between the PCEP
speakers before the stitching LSP association.
Stitching LSP Association could be created dynamically or configured
by the operator when operator-configured association is needed.
4.3. Stitching LSP Association TLV
The format of the Stitching LSP Association TLV is shown in Figure 3.
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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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |S|T|D|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Stitching LSP Association TLV
The fields of the Stitching LSP Association TLV are following:
Type:16 bits, it indicates the stitching LSP Association Group
TLV: TBD2, the value is assigned by IANA).
Length: the value is 4, it indicates the length of the TLV is 4
bytes.
Reserved: it is reserved for future use.
Stitching LSP Association Flags-S:1bit, indicates stitching LSP of
the source domain when it is set.
Stitching LSP Association Flags-T:1bit, indicates stitching LSP of
the transit domain when it is set.
Stitching LSP Association Flags-D:1bit, indicates stitching LSP of
the destination layer when it is set.
5. Security Considerations
TBA
6. Acknowledgements
TBA
7. IANA Considerations
7.1. New LSP Flag Registry
[RFC8231] defines the LSP object; per that RFC, IANA created a
registry to manage the value of the LSP object's Flag field. IANA is
requested to make allocations from the registry, as follows:
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+--------+------------------------------------+------------------+
| Value | Name | Reference |
+--------+------------------------------------+------------------+
| TBD | Request for Inter-domain Path (I) | [this document] |
+--------+------------------------------------+------------------+
Table 1
7.2. Association Object Type
This document defines a new association type and TLV in Association
object which originally defined in [I-D.ietf-pce-association-group].
IANA is requested to make allocations from the registry, as follows:
+--------+---------------------------------+------------------+
| Value | Name | Reference |
+--------+---------------------------------+------------------+
| TBD | Stitching LSP Association Type | [this document] |
| TBD | Stitching LSP Association TLV | [this document] |
+--------+---------------------------------+------------------+
Table 2
8. Normative References
[I-D.ietf-pce-association-group]
Minei, I., Crabbe, E., Sivabalan, S., Ananthakrishnan, H.,
Dhody, D., and Y. Tanaka, "Path Computation Element
Communication Protocol (PCEP) Extensions for Establishing
Relationships Between Sets of Label Switched Paths
(LSPs)", draft-ietf-pce-association-group-10 (work in
progress), August 2019.
[I-D.xiong-pce-stateful-pce-sr-inter-domain]
Xiong, Q., hu, f., Mirsky, G., and W. Cheng, "Stateful PCE
for SR-MPLS Inter-domain", draft-xiong-pce-stateful-pce-
sr-inter-domain-01 (work in progress), July 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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[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>.
Authors' Addresses
Quan Xiong
ZTE Corporation
No.6 Huashi Park Rd
Wuhan, Hubei 430223
China
Phone: +86 27 83531060
Email: xiong.quan@zte.com.cn
Greg Mirsky
ZTE Corporation
USA
Email: gregimirsky@gmail.com
Fangwei Hu
Individual
China
Email: hufwei@gmail.com
Weiqiang Cheng
China Mobile
Beijing
China
Email: chengweiqiang@chinamobile.com
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