SPRING S. Hegde Internet-Draft Juniper Networks Inc. Intended status: Standards Track P. Psenak Expires: 14 September 2023 Cisco Systems B. Decraene Orange 13 March 2023 BGP-LS extensions for IP Flexible Algorithms and Bandwidth, Delay, Metrics and Constraints draft-hegde-idr-bgpls-ip-flex-algo-bw-con-00 Abstract Flexible Algorithm is a mechanism that allows Link state routing protocols (viz. OSPF and IS-IS) to compute paths over a network based on user-defined (and hence, flexible) constraints and metrics. The computation is performed by routers participating in the specific network in a distributed manner using a Flexible Algorithm definition. This definition provisioned on one or more routers and propagated (viz. OSPF and IS- IS flooding) through the network. IP Flex-algo enables these constraint based paths to be built in a network which is purely IP and does not support MPLS or SRv6 forwarding plane. BGP Link-State (BGP-LS) enables the collection of various topology information from the network. This draft defines extensions to BGP- LS address-family to advertise bandwidth, delay and metric related constraints in Flexible algorithm definition. It also defines BGP-LS extensions required to advertise IP flexible algorithm related extensions in BGP-LS. 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]. 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/. Hegde, et al. Expires 14 September 2023 [Page 1] Internet-Draft BGP-LS extensions for IP Flexible Algori March 2023 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 14 September 2023. Copyright Notice Copyright (c) 2023 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Generic Metric Advertisement in BGP-LS . . . . . . . . . . . 3 2.1. BGP-LS Generic Metric TLV . . . . . . . . . . . . . . . . 4 3. BGP-LS FAD constraint sub-TLVs . . . . . . . . . . . . . . . 4 3.1. Flexible Algorithm Exclude Minimum Bandwidth . . . . . . 4 3.2. Flexible Algorithm Exclude Maximum Delay . . . . . . . . 5 3.3. Flexible Algorithm Reference Bandwidth . . . . . . . . . 5 3.4. Flexible Algorithm Bandwidth Threshold . . . . . . . . . 6 4. BGP-LS IP Algorithm TLV . . . . . . . . . . . . . . . . . . . 8 5. BGP-LS IP Algorithm Prefix Reachability TLV . . . . . . . . . 8 6. Backward Compatibility . . . . . . . . . . . . . . . . . . . 9 7. Security Considerations . . . . . . . . . . . . . . . . . . . 9 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 8.1. BGP-LS NLRI and Attribute TLVs . . . . . . . . . . . . . 9 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 10.1. Normative References . . . . . . . . . . . . . . . . . . 10 10.2. Informative References . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 Hegde, et al. Expires 14 September 2023 [Page 2] Internet-Draft BGP-LS extensions for IP Flexible Algori March 2023 1. Introduction Flexible Algorithm [RFC9350] is defined as a set of parameters consisting of calculation-type, metric-type and a set of constraints for allowing operators to have more control over the network path computation. [I-D.ietf-lsr-flex-algo-bw-con] defines further extensions to Flexible Algorithm that will allow operators additional control over their traffic flow, especially with respect to constraints about metric, delay and bandwidth. [I-D.ietf-lsr-ip-flexalgo] enables constraint based paths to be built in a network which is purely IP and does not support MPLS or SRv6 forwarding plane. This document defines BGP-LS related extensions to carry the information specific to Flexible Algorithms delay and bandwidth constraints as well as extensions related to IP Flexible-Algorithms. 2. Generic Metric Advertisement in BGP-LS Generic Metric as defined in [I-D.ietf-lsr-flex-algo-bw-con] is advertised as a Link attribute [RFC7752]. The Generic Metric may be either sourced from ISIS, OSPFv2 or OSPFv3. When the Generic Metric is sourced from below TLVs in ISIS TLV-22 (Extended IS reachability) [RFC5305] TLV-222 (MT-ISN) [RFC5120] TLV-23 (IS Neighbor Attribute) [RFC5311] TLV-223 (MT IS Neighbor Attribute) [RFC5311] TLV-141 (inter-AS reachability information) [RFC5316] OR is sourced from below TLVs in OSPF sub-TLV of the OSPF Link TLV of OSPF extended Link LSA [RFC7684]. sub-TLV of TE Link TLV (2) of OSPF TE LSA [RFC3630]. sub-TLV of the Router-Link TLV in the E-Router-LSA in OSPFv3 [RFC8362]. It is advertised as link attribute TLV. Hegde, et al. Expires 14 September 2023 [Page 3] Internet-Draft BGP-LS extensions for IP Flexible Algori March 2023 When the Generic Metric is sourced from below TLV in ISIS and OSPF sub-TLV 16 (Application-Specific Link Attributes) of TLV 22/222/23/223/141 [RFC8919] sub-sub-TLV of Application-Specific Link Attributes sub-TLV [RFC8920]. It is advertised as a sub-TLV of Application Specific Link Attributes TLV [I-D.ietf-idr-bgp-ls-app-specific-attr] 2.1. BGP-LS Generic Metric 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | metric-type | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Value | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type : TBD (To be assigned by IANA) Length: 8 octets metric-type = A value from the IGP metric type registry Value : metric value (0- 4,294,967,295) Figure 1: BGP-LS Generic Metric TLV 3. BGP-LS FAD constraint sub-TLVs The sub-TLVs described in this section are advertised as the sub-TLV of the Flexible Algorithm Definition TLV [RFC9351]. These sub-TLVs are either sourced from ISIS, OSPF or OSPFv3 as described in [I-D.ietf-lsr-flex-algo-bw-con] 3.1. Flexible Algorithm Exclude Minimum Bandwidth Hegde, et al. Expires 14 September 2023 [Page 4] Internet-Draft BGP-LS extensions for IP Flexible Algori March 2023 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Min Bandwidth | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ where: Type: TBD Length: 4 octets. Min Bandwidth: link bandwidth is encoded in 32 bits in IEEE floating point format. The units are bytes per second. Figure 2: BGP-LS FAEMB sub-TLV 3.2. Flexible Algorithm Exclude Maximum Delay 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max Delay | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ where: Type: TBD Length: 3 octets Max link delay: Maximum link delay in microseconds Figure 3: BGP-LS FAEMD sub-TLV 3.3. Flexible Algorithm Reference Bandwidth Hegde, et al. Expires 14 September 2023 [Page 5] Internet-Draft BGP-LS extensions for IP Flexible Algori March 2023 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reference Bandwidth | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Granularity Bandwidth | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ where: Type: TBD Length: 14 octets. Reference Bandwidth: Bandwidth encoded in 32 bits in IEEE floating point format. The units are in bytes per second. Granularity Bandwidth: Bandwidth encoded in 32 bits in IEEE floating point format. The units are in bytes per second. Flags: 0 1 2 3 4 5 6 7 +-+-+-+-+-+-+-+-+ |G| | | | +-+-+-+-+-+-+-+-+ G-flag: when set, interface group Mode MUST be used to derive total link bandwidth. Metric calculation: (Reference_bandwidth) / (Total_link_bandwidth - (Modulus of (Total_link_bandwidth, Granularity_bw))) Figure 4: BGP-LS FADRB sub-TLV 3.4. Flexible Algorithm Bandwidth Threshold Hegde, et al. Expires 14 September 2023 [Page 6] Internet-Draft BGP-LS extensions for IP Flexible Algori March 2023 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Bandwidth Threshold 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Threshold Metric 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Bandwidth Threshold 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Threshold Metric 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Bandwidth Threshold 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ..... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Threshold Metric n-1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Bandwidth Threshold n | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Threshold Metric n | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ where: Type: TBD Length: 2 + n*8 octets. Here n is equal to number of Threshold Metrics specified. n MUST be greater than or equal to 1. Flags: 0 1 2 3 4 5 6 7 +-+-+-+-+-+-+-+-+ |G| | | | +-+-+-+-+-+-+-+-+ G-flag: when set, interface group Mode MUST be used to derive total link bandwidth. Staircase bandwidth threshold and associated metric values. Hegde, et al. Expires 14 September 2023 [Page 7] Internet-Draft BGP-LS extensions for IP Flexible Algori March 2023 Bandwidth Threshold 1: Minimum Link Bandwidth is encoded in 32 bits in IEEE floating point format. The units are bytes per second. Bandwidth Threshold 2: Maximum Link Bandwidth is encoded in 32 bits in IEEE floating point format. The units are bytes per second. Threshold Metric 1 : metric value range (1 - 4,294,967,296) Figure 5: OSPF FADBT sub-TLV 4. BGP-LS IP Algorithm TLV BGP-LS IP algorithm TLV is a node Attribute TLV and is encoded along with the Node NLRI. The TLV may be sourced from ISIS and/or OSPF as defined in section 5.1 and 5.2 of [I-D.ietf-lsr-ip-flexalgo] . 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Algorithm 1 | Algorithm... | Algorithm n | | +- -+ | | + + * Type: IP Algorithm TLV (Value TBD by IANA) * Length: Variable * Algorithm (1 octet): Value from 128 to 255. Figure 6: BGP-LS IP Algorithm TLV 5. BGP-LS IP Algorithm Prefix Reachability TLV The IP algorithm Prefix Reachability TLV is advertised as a Prefix Attribute and may be associated with an IPv4 or an IPv6 Prefix. This TLV MUST appear only once in a Prefix NLRI. If the IP algorithm Prefix Reachability TLV is present, Prefix Metric TLV MUST NOT be added. IP algorithm Prefix Reachability TLV is present, IGP Flags TLV carries the flags for IP algorithm Prefix Reachability TLV. Hegde, et al. Expires 14 September 2023 [Page 8] Internet-Draft BGP-LS extensions for IP Flexible Algori March 2023 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 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Algorithm| Reserved | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Metric | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type (2 octets) : The value is TBD. * Length (2 octet): 8 * Algorithm (1 octet): Associated Algorithm from 128 to 255. * Reserved: (3 octets). SHOULD be set to 0 on transmission and MUST be ignored on reception. * Metric (4 octets): The algorithm specific metric value. The metric value of 0XFFFFFFFF MUST be considered as unreachable. * Flags (1 octet): None defined Figure 7: BGP-LS IP Algorithm Prefix Reachability TLV 6. Backward Compatibility 7. Security Considerations TBD 8. IANA Considerations 8.1. BGP-LS NLRI and Attribute TLVs BGP-LS NLRI and Attribute TLV registry is updated to include newly defined Node, link and prefix attriute TLVs. Hegde, et al. Expires 14 September 2023 [Page 9] Internet-Draft BGP-LS extensions for IP Flexible Algori March 2023 +-----------+---------------------+------------------------------+ | TLV Code | Description | Reference | | Point | | (RFC/Section) | +------------+---------------------+------------------------------+ | TBD1 | IP Algorithm TLV | draft-ietf-lsr-ip-flexalgo | | | | Section 5.1/5.2 | | TBD2 | IPv4 Algorithm |draft-ietf-lsr-ip-flexalgo | | | Prefix Reachability | section 6.1 to 6.4 | | | TLV | | | TBD3 | Generic Metric TLV |draft-ietf-lsr-flex-algo-bw-con | | | Section 2.1 and 2.2 | | TBD4 |Flexible Algorithm |draft-ietf-lsr-flex-algo-bw-con | |Exclude Minimum |Section 3.1.1 and 3.2.1 | | |Bandwidth | | | TBD5 |Flexible Algorithm |draft-ietf-lsr-flex-algo-bw-con | |Exclude Maximum |Section 3.1.2 and 3.2.2 | | |Delay | | | TBD6 |Flexible Algorithm |draft-ietf-lsr-flex-algo-bw-con | |Reference Bandwidth |Section 4.1.3.1 and 4.1.4.1 | | TBD7 |Flexible Algorithm |draft-ietf-lsr-flex-algo-bw-con | | Bandwidth Threshold |Section 4.1.3.2 and 4.1.4.2 | +------------+---------------------+------------------------------+ Figure 8: IANA BGP-LS NLRI and Attribute TLVs 9. Acknowledgements 10. References 10.1. Normative References [I-D.ietf-idr-bgp-ls-app-specific-attr] Talaulikar, K., Psenak, P., and J. Tantsura, "Application- Specific Link Attributes Advertisement Using the Border Gateway Protocol - Link State (BGP-LS)", Work in Progress, Internet-Draft, draft-ietf-idr-bgp-ls-app-specific-attr- 16, 7 July 2022, . [I-D.ietf-lsr-flex-algo-bw-con] Hegde, S., Britto, W., Shetty, R., Decraene, B., Psenak, P., and T. Li, "Flexible Algorithms: Bandwidth, Delay, Metrics and Constraints", Work in Progress, Internet- Draft, draft-ietf-lsr-flex-algo-bw-con-06, 10 March 2023, . Hegde, et al. Expires 14 September 2023 [Page 10] Internet-Draft BGP-LS extensions for IP Flexible Algori March 2023 [I-D.ietf-lsr-ip-flexalgo] Britto, W., Hegde, S., Kaneriya, P., Shetty, R., Bonica, R., and P. Psenak, "IGP Flexible Algorithms (Flex- Algorithm) In IP Networks", Work in Progress, Internet- Draft, draft-ietf-lsr-ip-flexalgo-08, 19 December 2022, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering (TE) Extensions to OSPF Version 2", RFC 3630, DOI 10.17487/RFC3630, September 2003, . [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic Engineering", RFC 5305, DOI 10.17487/RFC5305, October 2008, . [RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W., Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute Advertisement", RFC 7684, DOI 10.17487/RFC7684, November 2015, . [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, . [RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and F. Baker, "OSPFv3 Link State Advertisement (LSA) Extensibility", RFC 8362, DOI 10.17487/RFC8362, April 2018, . [RFC8919] Ginsberg, L., Psenak, P., Previdi, S., Henderickx, W., and J. Drake, "IS-IS Application-Specific Link Attributes", RFC 8919, DOI 10.17487/RFC8919, October 2020, . [RFC8920] Psenak, P., Ed., Ginsberg, L., Henderickx, W., Tantsura, J., and J. Drake, "OSPF Application-Specific Link Attributes", RFC 8920, DOI 10.17487/RFC8920, October 2020, . Hegde, et al. Expires 14 September 2023 [Page 11] Internet-Draft BGP-LS extensions for IP Flexible Algori March 2023 [RFC9350] Psenak, P., Ed., Hegde, S., Filsfils, C., Talaulikar, K., and A. Gulko, "IGP Flexible Algorithm", RFC 9350, DOI 10.17487/RFC9350, February 2023, . [RFC9351] Talaulikar, K., Ed., Psenak, P., Zandi, S., and G. Dawra, "Border Gateway Protocol - Link State (BGP-LS) Extensions for Flexible Algorithm Advertisement", RFC 9351, DOI 10.17487/RFC9351, February 2023, . 10.2. Informative References [RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi Topology (MT) Routing in Intermediate System to Intermediate Systems (IS-ISs)", RFC 5120, DOI 10.17487/RFC5120, February 2008, . [RFC5311] McPherson, D., Ed., Ginsberg, L., Previdi, S., and M. Shand, "Simplified Extension of Link State PDU (LSP) Space for IS-IS", RFC 5311, DOI 10.17487/RFC5311, February 2009, . [RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in Support of Inter-Autonomous System (AS) MPLS and GMPLS Traffic Engineering", RFC 5316, DOI 10.17487/RFC5316, December 2008, . [RFC7471] Giacalone, S., Ward, D., Drake, J., Atlas, A., and S. Previdi, "OSPF Traffic Engineering (TE) Metric Extensions", RFC 7471, DOI 10.17487/RFC7471, March 2015, . [RFC8570] Ginsberg, L., Ed., Previdi, S., Ed., Giacalone, S., Ward, D., Drake, J., and Q. Wu, "IS-IS Traffic Engineering (TE) Metric Extensions", RFC 8570, DOI 10.17487/RFC8570, March 2019, . Authors' Addresses Shraddha Hegde Juniper Networks Inc. Exora Business Park Bangalore 560103 KA India Email: shraddha@juniper.net Hegde, et al. Expires 14 September 2023 [Page 12] Internet-Draft BGP-LS extensions for IP Flexible Algori March 2023 Peter Psenak Cisco Systems Email: ppsenak@cisco.com Bruno Decraene Orange Email: bruno.decraene@orange.com Hegde, et al. Expires 14 September 2023 [Page 13]