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. 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 7 January 2023. 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 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. Xiong, et al. Expires 7 January 2023 [Page 1] Internet-Draft PCEP Extension for NRP-ID July 2022 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. Xiong, et al. Expires 7 January 2023 [Page 2] Internet-Draft PCEP Extension for NRP-ID July 2022 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. Xiong, et al. Expires 7 January 2023 [Page 3] Internet-Draft PCEP Extension for NRP-ID July 2022 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. Xiong, et al. Expires 7 January 2023 [Page 4] Internet-Draft PCEP Extension for NRP-ID July 2022 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, . [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, . [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, Xiong, et al. Expires 7 January 2023 [Page 5] Internet-Draft PCEP Extension for NRP-ID July 2022 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, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, DOI 10.17487/RFC4655, August 2006, . [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, DOI 10.17487/RFC5440, March 2009, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [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, . 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 Xiong, et al. Expires 7 January 2023 [Page 6] Internet-Draft PCEP Extension for NRP-ID July 2022 Email: peng.shaofu@zte.com.cn Vishnu Pavan Beeram Juniper Networks Email: vbeeram@juniper.net Tarek Saad Juniper Networks Email: tsaad@juniper.net Xiong, et al. Expires 7 January 2023 [Page 7]