PCE Q. Xiong Internet-Draft S. Peng Intended status: Standards Track ZTE Corporation Expires: 10 May 2022 V. Beeram T. Saad Juniper Networks November 2021 PCEP Extension for NRP-ID draft-xiong-pce-nrp-id-00 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 5 May 2022. Copyright Notice Copyright (c) 2021 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 Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Xiong, et al. Expires 10 May 2022 [Page 1] Internet-Draft PCEP Extension for NRP-ID November 2021 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 . . . . . . . . . . . . . . . . . . . . . . . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . 4 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. 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. IETF Network Slice is defined in [I-D.ietf-teas-ietf-network-slice-definition]. The slices may be viewed as virtual networks and partition the network resources into sub-topologies in transport network. Slice Aggregate is a a collection of packets that match a slice policy selection criteria and are given the same forwarding treatment as defined in [I-D.bestbar-teas-ns-packet]. And Network Resource Partition is the collection of resources that are used to support a slice aggregate. The identifier of Network Resource Partition (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. Xiong, et al. Expires 10 May 2022 [Page 2] Internet-Draft PCEP Extension for NRP-ID November 2021 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 in Network Slicing. 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 let the scope of path calculation to be limited in a specific network resources partition. There are many control plane technologies to realize network slice. Some control plane technologies may directly maintain resources per slice granularity in the link-state database, only for the case with small slice scalability. [I-D.bestbar-teas-ns-packet] proposes a more scalable slicing scheme. The resource information in link-state database is identified by NRP-ID to distinguish the logical topologies corresponding to different slice-aggregate. Within the controller, a slice-aggregate includes one or more slices mapped to it. If the number of slices is small, the resources per slice granularity can be maintained directly in the link-state database. In this case, different slice may be mapped to different slice- aggregate. If the number of slices is large, it is not recommended to maintain the slice granularity resources in the link-state database, but the aggregated granularity. Xiong, et al. Expires 10 May 2022 [Page 3] Internet-Draft PCEP Extension for NRP-ID November 2021 It is required to define a NRP-ID constraint in the TE purpose definition of overlay service. For example, VPN routes may have Color attribute (refer to [I-D.ietf-idr-tunnel-encaps] and [I-D.ietf-spring-segment-routing-policy]). Color represents aspecific TE purpose, which can contain an NRP-ID. When the controller receives the path computation request with a NRP- ID constraint, it can use the resources identified by specific NRP-ID in TED to calculate the path. PCE may maintain resources per path within the resource pool identified by NRP-ID. In a PCReq message, a PCC MAY insert one NRP-ID TLV to indicate the slice based virtual network that MUST be considered by the PCE. 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. In a PCRep/PCInit/PCUpd message, the NRP-ID TLV MAY be carried so as to provide the network slicing information for the computed path. The headend may put the NRP-ID, or other information that can be deduced to a NRP-ID, to an encapsulated data packet. 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 the identifier of Network Resource Partition to represent an IETF Network Slice that is defined in [I-D.ietf-teas-ietf-network-slice-definition]. 4. Security Considerations TBA Xiong, et al. Expires 10 May 2022 [Page 4] Internet-Draft PCEP Extension for NRP-ID November 2021 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.bestbar-teas-ns-packet] Saad, T., Beeram, V. P., Wen, B., Ceccarelli, D., Halpern, J., Peng, S., Chen, R., Liu, X., Contreras, L. M., and R. Rokui, "Realizing Network Slices in IP/MPLS Networks", Work in Progress, Internet-Draft, draft-bestbar-teas-ns- packet-04, 25 October 2021, . [I-D.ietf-idr-tunnel-encaps] Patel, K., Velde, G. V. D., Sangli, S. R., and J. Scudder, "The BGP Tunnel Encapsulation Attribute", Work in Progress, Internet-Draft, draft-ietf-idr-tunnel-encaps-22, 7 January 2021, . [I-D.ietf-spring-segment-routing-policy] Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and P. Mattes, "Segment Routing Policy Architecture", Work in Progress, Internet-Draft, draft-ietf-spring-segment- routing-policy-14, 25 October 2021, . Xiong, et al. Expires 10 May 2022 [Page 5] Internet-Draft PCEP Extension for NRP-ID November 2021 [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, . [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 Xiong, et al. Expires 10 May 2022 [Page 6] Internet-Draft PCEP Extension for NRP-ID November 2021 Nanjing Jiangsu, 210012 China 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 10 May 2022 [Page 7]