IDR R. Chen Internet-Draft Sh. Peng Intended status: Standards Track ZTE Corporation Expires: 30 June 2022 T. Saad V. Beeram Juniper Networks 27 December 2021 BGP-LS Extensions for Network Resource Partition identifier draft-chen-idr-bgp-ls-transport-slice-04 Abstract This draft defines extensions to BGP-LS protocol in order to advertise Network Resource Partition SR segments that share the same IGP computed forwarding path but offer a forwarding treatment (e.g. scheduling and drop policy) that is associated with a specific Network Resource. The draft is applicable to both SR-MPLS and SRv6 dataplanes 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 30 June 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 Chen, et al. Expires 30 June 2022 [Page 1] Internet-Draft BGP-LS Extensions for NRPID December 2021 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 2.2. Acronyms and Abbreviations . . . . . . . . . . . . . . . 3 3. NRPID SID for SR-MPLS . . . . . . . . . . . . . . . . . . . . 3 3.1. Node Attributes TLV . . . . . . . . . . . . . . . . . . . 4 3.2. Link Attribute TLVs . . . . . . . . . . . . . . . . . . . 4 3.2.1. NRPID list sub-TLV . . . . . . . . . . . . . . . . . 5 3.2.2. L2 Bundle Member NRPID TLV . . . . . . . . . . . . . 5 3.2.3. NRPID Adjacency-SID TLV . . . . . . . . . . . . . . . 6 3.2.4. NRPID LAN-Adj-SID TLV . . . . . . . . . . . . . . . . 7 3.3. Prefix Attribute TLVs . . . . . . . . . . . . . . . . . . 8 4. NRPID SID for SRv6 . . . . . . . . . . . . . . . . . . . . . 9 4.1. Router Capabilities for NRPID . . . . . . . . . . . . . . 9 4.2. NRPID SID sub-TLV . . . . . . . . . . . . . . . . . . . . 10 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 7. Security Considerations . . . . . . . . . . . . . . . . . . . 11 8. Normative References . . . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 1. Introduction Network slicing allows a Service Provider to create independent and logical networks on top of a common or shared physical network infrastructure.[I-D.ietf-teas-ietf-network-slices] provides the definition of a network slice for use within the IETF and discusses the general framework for requesting and operating IETF Network Slices, their characteristics, and the necessary system components and interfaces. It also defines the term "network resource partition(NRP)", which means a set of network resources that are available to carry traffic and meet the SLOs and SLEs. [I-D.bestbar-teas-ns-packet] proposes the solution to realize network slicing in IP/MPLS networks. It introduces the notion of a slice aggregate which comprises of one of more IETF network slice traffic streams and use network resource partition identifier (NRP-ID) to distinguish slice aggregation. Chen, et al. Expires 30 June 2022 [Page 2] Internet-Draft BGP-LS Extensions for NRPID December 2021 [I-D.bestbar-lsr-spring-sa]describes extensions to the IS-IS that enable advertising Network Resource Partition identifier(NRPID) SR segments that share the same IGP computed forwarding path but offer a forwarding treatment (e.g. scheduling and drop policy) that is associated with a specific Slice Aggregate. In order to satisfy the need for applications that require topological visibility across one area or Autonomous System (AS). This document specifies extensions to the BGP Link-state address- family in order to advertise the information of Network Resource Partition SIDs. An external component (e.g., a controller) then can collect Network Resource Partition SIDs in the "northbound" direction. The draft is applicable to both SR-MPLS and SRv6 dataplanes. 2. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. cloud transport network: It is usually a national or province backbone network to achieve interconnection between multiple regional clouds/core clouds deployed in the country/province. 2.1. Terminology Slice Aggregate:a collection of packets that match a slice policy selection criteria and are given the same forwarding treatment; a slice aggregate comprises of one or more IETF network slice traffic streams; the mapping of one or more IETF network slices to a slice aggregate is maintained by the IETF Network Slice Controller. Network Resource Partition:the collection of resources that are used to support a slice aggregate. 2.2. Acronyms and Abbreviations NRPID: Network Resource Partition identifier. 3. NRPID SID for SR-MPLS BGP-LS[[RFC7752]]defines the link-state NLRI that can be a Node NLRI, a Link NLRI or a Prefix NLRI. The link-state information is mapped to BGP link-state NLRI within the BGP-LS Attribute. In addition, [I-D.ietf-idr-bgpls-inter-as-topology-ext]defines Stub Link NLRI that is used to describe the inter-as link. This document adds additional BGP-LS Attribute TLVs in order to encode Network Resource Partition Chen, et al. Expires 30 June 2022 [Page 3] Internet-Draft BGP-LS Extensions for NRPID December 2021 information. It does not introduce any changes to the encoding of the BGP-LS NLRIs. 3.1. Node Attributes TLV The Network Resource abbribute TLV is used in order to advertise which Network Resource a router wants to take part in. The NRPID sub-TLV is a new TLV of the optional BGP-LS Attribute that is associated with the node NLRI. The NRPID TLV has the following format: 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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type=TBD1 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NRPID-1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NRPID-n | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1 where: Type: TBD1 (Suggested value to be assigned by IANA) Length: variable. NRPID: Network Resource Partition ID is used to indication the resources on specific link(s)/node(s) that will be traversed by a slice-aggregate. 3.2. Link Attribute TLVs The following Link Attribute TLVs are are defined: Chen, et al. Expires 30 June 2022 [Page 4] Internet-Draft BGP-LS Extensions for NRPID December 2021 +-------+---------------------------------------------+ | Type | Description | +-------+---------------------------------------------+ | TBD2 | NRPID list TLV | | TBD3 | L2 Bundle Member NRPID TLV | | TBD4 | NRPID Adjacency-SID TLV | | TBD5 | NRPID LAN-Adj-SID TLV | +-------+---------------------------------------------+ Figure 2: xml_happy2 These TLVs should only be added to the BGP-LS Attribute associated with the Link NLRI or Stub Link NLRI. 3.2.1. NRPID list sub-TLV The NRPID list sub-TLV has the following format: 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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type=TBD2 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NRPID-1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NRPID-n | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3 Type: TBD2 (Suggested value to be assigned by IANA) Length: variable. NRPID:Network Resource Partition ID is used to indication the resources on specific link(s)/node(s) that will be traversed by a slice-aggregate. 3.2.2. L2 Bundle Member NRPID TLV This TLV is used to advertise NRSP for L2 Bundle Member associated with a parent L3 adjacency which is Point-to-Point. The following format is defined for this sub-TLV: Chen, et al. Expires 30 June 2022 [Page 5] Internet-Draft BGP-LS Extensions for NRPID December 2021 Type: TBD3. Length: variable. L2 Bundle Member NRPID. There MUST be one NRPID for each of the L2 Bundle Members advertised under the preceding L2 Bundle Member Attribute Descriptor. The parrent link can be configured to an IGP instance, or as an inter-as link. 3.2.3. NRPID Adjacency-SID TLV This TLV is used to advertise multiple NRPID Adj-SIDs to the controller, Adjacency-SID need to be allocated per NRPID. This information is derived from IS-IS Slice Aggregate Adjacency-SID Sub- TLV of IS-IS (section 3.2 of [I-D.bestbar-lsr-spring-sa] ). The following format is defined for this sub-TLV: 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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type=TBD4 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | Weight | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NRPID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SID/Index/Label(Variable) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4 where: Type:TBD4(Suggested value to be assigned by IANA) Length: Variable. Depending on the size of the SID. Weight: Variable. 1 octet carrying the weight used for load-balancing purposes. The use of weight is described in section 3.4 of [RFC8402]. NRPID: Identifies the Network Resource Partition information corresponding to the Adjacency-SID. The "Flags" and "SID/Index/Label" fields are the same as the Adjacency-SID sub-TLV [RFC8667]. Chen, et al. Expires 30 June 2022 [Page 6] Internet-Draft BGP-LS Extensions for NRPID December 2021 3.2.4. NRPID LAN-Adj-SID TLV In LAN subnetworks,[RFC8667] defines the LAN-Adj-SID sub-TLV for a router to advertise the Adj-SID of each of its neighbors. NRPID LAN-Adj-SID TLV is used to advertise multiple SA LAN-Adj-SIDs, Adjacency-SID need to be allocated per NRPID. This information is derived from the IS-IS Slice Aggregate LAN Adjacency-SIDs of IS-IS (section 3.3 of I-D. [I-D.bestbar-lsr-spring-sa] ). 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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type=TBD5 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | Weight | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Neighbor System-ID (ID length octets) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NRPID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SID/Label/Index (variable) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5 where: Type:TBD5 (Suggested value to be assigned by IANA) Length: Variable. Depending on the size of the SID. The "Flags" and "SID/Index/Label" fields are the same as the Adjacency-SID sub-TLV [RFC8667]. NRPID: Identifies the Network Resource Partition information corresponding to the LAN-Adjacency-SID. Chen, et al. Expires 30 June 2022 [Page 7] Internet-Draft BGP-LS Extensions for NRPID December 2021 3.3. Prefix Attribute TLVs NRPID Prefix-SID TLV should only be added to the BGP-LS Attribute associated with the Prefix NLRI describing the prefix of the IGP node.This TLV is used to advertising multiple NRPID Prefix-SIDs.This information is derived from IS-IS Slice Aggregate Prefix-SID Sub-TLV of IS-IS (section 3.1 of [I-D.bestbar-lsr-spring-sa]). The Prefix-SID for NRPID TLV has the following format: 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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type=TBD6 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flag | Algorithm | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NRPID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SID/Index/Label(Variable) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 6 where: Type:TBD6 (Suggested value to be assigned by IANA) Length: Variable. Depending on the size of the SID. The "Flags" and "SID/Index/Label" fields are the same as the Prefix- SID sub-TLV [RFC8667]. Algorithm: Accoridng to section "3.2. SR-Algorithm Sub-TLV" of [RFC8667], two values can be set in this field. * 0: Shortest Path First (SPF) algorithm based on link metric. * 1: Strict Shortest Path First (SPF) algorithm based on link metric. Note that[I-D.ietf-lsr-flex-algo]also allows user to define other algorithm values, i.e., FA-id within [128, 255], for the purpose of constraint based path computation.However, an FA-id algorithm value MUST not be set in this field, the reason is that FA-id has not semantic local within AII. Chen, et al. Expires 30 June 2022 [Page 8] Internet-Draft BGP-LS Extensions for NRPID December 2021 NRPID: Identifies the NRPID information corresponding to the Prefix- SID. 4. NRPID SID for SRv6 SRv6 attributes with an IPv6 prefix are advertised using the new BGP- LS Attribute TLVs defined in this section and associated with the BGP-LS Prefix NLRI. 4.1. Router Capabilities for NRPID This BGP-LS Attribute TLV is used to announce which NRPID a router wants to take part in. The Router Capabilities for NRPID has the following format: 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=TBD7 | Length | Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NRPID-1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ...... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NRPID-n | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7 where: Type: TBD7. Length: variable. Number:Number of slice-aggregate which share the same topology. NRPID: Network Resource Partition ID is used to indication the resources on specific link(s)/node(s) that will be traversed by a slice-aggregate. Chen, et al. Expires 30 June 2022 [Page 9] Internet-Draft BGP-LS Extensions for NRPID December 2021 4.2. NRPID SID sub-TLV The SRv6 Locator TLV was introduced in [I-D.ietf-idr-bgpls-srv6-ext] to advertise SRv6 Locators and additional attributes for the given SRv6 Locator. A new NRPID SID sub-TLV under the SRv6 Locator TLV is defined to advertise an Locator that is associated with a specific NRPID. The NRPID SRv6 Locator has the following format: 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=TBD8 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NRPID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 8 where: Type: TBD8 Length: 4 octets. NRPID: Identifies the NRPID information corresponding to an Locator. The new NRPID SID sub-TLV is an optional Sub-TLV of: SRv6 End.X SID TLV (Section 4.1 of [I-D.ietf-idr-bgpls-srv6-ext]. SRv6 LAN End.X SID TLV (Section 4.2 of [I-D.ietf-idr-bgpls-srv6-ext]. 5. Acknowledgements TBD. 6. IANA Considerations This document makes no request of IANA. Chen, et al. Expires 30 June 2022 [Page 10] Internet-Draft BGP-LS Extensions for NRPID December 2021 7. Security Considerations Procedures and protocol extensions defined in this document do not affect the BGP security model. See the "Security Considerations"section of [RFC4271] for a discussion of BGP security. Also, refer to [RFC4272] and [RFC6952] for analyses of security issues for BGP. Security considerations for acquiring and distributing BGP-LS information are discussed in [RFC7752]. 8. Normative References [I-D.bestbar-lsr-spring-sa] Saad, T., Beeram, V. P., Chen, R., Peng, S., Wen, B., and D. Ceccarelli, "IGP Extensions for SR Slice Aggregate SIDs", Work in Progress, Internet-Draft, draft-bestbar- lsr-spring-sa-01, 16 September 2021, . [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., Rokui, R., and L. Jalil, "Realizing Network Slices in IP/MPLS Networks", Work in Progress, Internet-Draft, draft- bestbar-teas-ns-packet-06, 22 December 2021, . [I-D.ietf-idr-bgpls-inter-as-topology-ext] Wang, A., Chen, H., Talaulikar, K., and S. Zhuang, "BGP-LS Extension for Inter-AS Topology Retrieval", Work in Progress, Internet-Draft, draft-ietf-idr-bgpls-inter-as- topology-ext-10, 12 October 2021, . [I-D.ietf-idr-bgpls-srv6-ext] Dawra, G., Filsfils, C., Talaulikar, K., Chen, M., Bernier, D., and B. Decraene, "BGP Link State Extensions for SRv6", Work in Progress, Internet-Draft, draft-ietf- idr-bgpls-srv6-ext-09, 10 November 2021, . Chen, et al. Expires 30 June 2022 [Page 11] Internet-Draft BGP-LS Extensions for NRPID December 2021 [I-D.ietf-lsr-flex-algo] Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and A. Gulko, "IGP Flexible Algorithm", Work in Progress, Internet-Draft, draft-ietf-lsr-flex-algo-18, 25 October 2021, . [I-D.ietf-teas-ietf-network-slices] Farrel, A., Gray, E., 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-05, 25 October 2021, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, DOI 10.17487/RFC4271, January 2006, . [RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis", RFC 4272, DOI 10.17487/RFC4272, January 2006, . [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of BGP, LDP, PCEP, and MSDP Issues According to the Keying and Authentication for Routing Protocols (KARP) Design Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, . [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and S. Ray, "North-Bound Distribution of Link-State and Traffic Engineering (TE) Information Using BGP", RFC 7752, DOI 10.17487/RFC7752, March 2016, . [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., Decraene, B., Litkowski, S., and R. Shakir, "Segment Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, July 2018, . Chen, et al. Expires 30 June 2022 [Page 12] Internet-Draft BGP-LS Extensions for NRPID December 2021 [RFC8667] Previdi, S., Ed., Ginsberg, L., Ed., Filsfils, C., Bashandy, A., Gredler, H., and B. Decraene, "IS-IS Extensions for Segment Routing", RFC 8667, DOI 10.17487/RFC8667, December 2019, . Authors' Addresses Ran Chen ZTE Corporation Nanjing China Email: chen.ran@zte.com.cn Shaofu Peng ZTE Corporation Nanjing China Email: peng.shaofu@zte.com.cn Tarek Saad Juniper Networks Email: tsaad@juniper.net Vishnu Pavan Beeram Juniper Networks Email: vbeeram@juniper.net Chen, et al. Expires 30 June 2022 [Page 13]