Internet DRAFT - draft-xiong-pce-nrp-id
draft-xiong-pce-nrp-id
PCE Q. Xiong
Internet-Draft S. Peng
Intended status: Standards Track ZTE Corporation
Expires: 7 January 2023 V. Beeram
T. Saad
Juniper Networks
6 July 2022
PCEP Extension for NRP-ID
draft-xiong-pce-nrp-id-01
Abstract
This document proposes a set of extensions for PCEP to support the
identifier of Network Resource Partition (NRP-ID) as the constraint
of network slicing during path computation.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 7 January 2023.
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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 Extensions for Network Resource Partition . . . . . . . 3
3.1. NRP-ID TLV . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Protocol Operation . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 5
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. Normative References . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 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. As depicted
in [RFC4655], a PCE MUST be able to compute the path of a TE LSP by
operating on the TED and considering bandwidth and other constraints
applicable to the TE LSP service request. The constraint parameters
are provided such as metric, bandwidth, delay, affinity, etc.
However these parameters can't meet the network slicing requirements.
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According to 5G context, network slicing is the collection of a set
of technologies to support network service differentiation and
meeting the diversified requirements from vertical industries. As
defined in [I-D.ietf-teas-ietf-network-slice-definition], an IETF
network slice is a logical network topology connecting a number of
endpoints using a set of shared or dedicated network resources that
are used to satisfy specific Service Level Objectives (SLOs). As
defined in [I-D.ietf-teas-ietf-network-slices], a Network Resource
Partition (NRP) is a collection of resources (bufferage, queuing,
scheduling, etc.) in the underlay network to support the IETF Network
Slice service (or any other service that needs logical network
structures with required characteristics to be created). And as per
[I-D.ietf-teas-ns-ip-mpls], NRP Identifier (NRP-ID) indicates an
identifier that is globally unique within an NRP domain and that can
be used in the control or management plane to identify the resources
associated with the NRP. The NRP-ID could be used to identify the
slice and network resource and viewed as constraints of network
slicing when PCE is deployed. PCE MUST take the identifier of
slicing into consideration during path computation.
This document proposes a set of extensions for PCEP to support the
NRP-ID as the constraint of network slicing during path computation.
2. Conventions used in this document
2.1. Terminology
The terminology is defined as [RFC5440] and
[I-D.ietf-teas-ietf-network-slice-definition].
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 Extensions for Network Resource Partition
As defined in [RFC5440] , the LSPA object is used to specify the LSP
attributes to be taken into account by the PCE during path
computation such as constraints. This document proposes new TLV for
the LSPA object to carry TE constraints for network slicing.
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3.1. NRP-ID TLV
The NRP-ID TLV is optional and is defined to carry the slice specific
constraint. PCEP message needs to carry NRP-ID to limit the network
resources for path calculation within a NRP domain.
The format of the NRP-ID TLV is shown as 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=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NRP-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Figure 1: NRP-ID TLV
The code point for the TLV type is TBD1. The TLV length is 4 octets.
NRP-ID (32 bits): indicates a NRP Identifier as defined in
[I-D.ietf-teas-ns-ip-mpls].
3.2. Protocol Operation
As defined in [I-D.ietf-teas-ns-ip-mpls], NRP state aware TE (NRP-TE)
should implement the TE path selection that takes into account the
available network resources associated with a specific NRP. The NRP-
ID TLV should be carried in PCEP messages when computing NRP state
aware TE paths. The PCE may maintain network resources per path and
the NRP state within the resource pool identified by NRP-ID.
In a PCReq message, a PCC MAY request the PCC to compute the NRP-TE
path and insert a NRP-ID TLV to indicate the resources within a NRP
domain. The PCE will perform path computation based on the intra-
domain or inter- domain sub-topology identified by the specific NRP-
ID, that can be used to find the corresponding customized topology or
referenced topology, and corresponding resources. The PCE may reply
the PCC with NRP-ID TLV carried in PCRep message and the headend may
insert the NRP-ID into an encapsulated data packet. In case of
unsuccessful path computation when the NRP-ID constraint could not be
satisfied, the the PCRep message may contain a NO-PATH object.
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In a PCInit/PCUpd message, the PCE MAY compute the optimal NRP-TE
path and carry the NRP-ID TLV so as to provide the network slicing
information. If a PCC is unable to recognize a NRP-ID value passed
in an LSP PCInit/PCUpd request, the PCC must keep the LSP in DOWN
state, and include an LSP Error Code value of "Unsupported NRP"
[Value to be assigned by IANA] in LSP State Report message.
4. Security Considerations
TBA
5. Acknowledgements
TBA
6. IANA Considerations
IANA is requested to make allocations from the registry, as follows:
+======+============+=================+
| Type | TLV | Reference |
+======+============+=================+
| TBD1 | NRP-ID TLV | [this document] |
+------+------------+-----------------+
Table 1
7. Normative References
[I-D.ietf-teas-ietf-network-slice-definition]
Rokui, R., Homma, S., Makhijani, K., Contreras, L. M., and
J. Tantsura, "Definition of IETF Network Slices", Work in
Progress, Internet-Draft, draft-ietf-teas-ietf-network-
slice-definition-01, 22 February 2021,
<https://www.ietf.org/archive/id/draft-ietf-teas-ietf-
network-slice-definition-01.txt>.
[I-D.ietf-teas-ietf-network-slices]
Farrel, A., Drake, J., Rokui, R., Homma, S., Makhijani,
K., Contreras, L. M., and J. Tantsura, "Framework for IETF
Network Slices", Work in Progress, Internet-Draft, draft-
ietf-teas-ietf-network-slices-12, 30 June 2022,
<https://www.ietf.org/archive/id/draft-ietf-teas-ietf-
network-slices-12.txt>.
[I-D.ietf-teas-ns-ip-mpls]
Saad, T., Beeram, V. P., Dong, J., Wen, B., Ceccarelli,
D., Halpern, J., Peng, S., Chen, R., Liu, X., Contreras,
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L. M., Rokui, R., and L. Jalil, "Realizing Network Slices
in IP/MPLS Networks", Work in Progress, Internet-Draft,
draft-ietf-teas-ns-ip-mpls-00, 16 June 2022,
<https://www.ietf.org/archive/id/draft-ietf-teas-ns-ip-
mpls-00.txt>.
[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>.
[RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
Computation Element (PCE)-Based Architecture", RFC 4655,
DOI 10.17487/RFC4655, August 2006,
<https://www.rfc-editor.org/info/rfc4655>.
[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>.
[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
Email: xiong.quan@zte.com.cn
Shaofu Peng
ZTE Corporation
No.50 Software Avenue
Nanjing
Jiangsu, 210012
China
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Email: peng.shaofu@zte.com.cn
Vishnu Pavan Beeram
Juniper Networks
Email: vbeeram@juniper.net
Tarek Saad
Juniper Networks
Email: tsaad@juniper.net
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