Network Working Group G. Fioccola Internet-Draft Huawei Intended status: Standards Track R. Pang Expires: 12 March 2023 China Unicom S. Wang China Telecom B. Decraene Orange S. Zhuang H. Wang Huawei 8 September 2022 BGP Extension for Advertising In-situ Flow Information Telemetry (IFIT) Capabilities draft-ietf-idr-bgp-ifit-capabilities-01 Abstract In-situ Flow Information Telemetry (IFIT) refers to network OAM data plane on-path telemetry techniques, in particular In-situ OAM (IOAM) and Alternate Marking. This document defines extensions to Border Gateway Protocol (BGP) to advertise the In-situ Flow Information Telemetry (IFIT) capabilities. Within an IFIT domain, IFIT- capability advertisement from the tail node to the head node assists the head node to determine whether a particular IFIT Option type can be encapsulated in data packets. Such advertisement would be useful for mitigating the leakage threat and facilitating the deployment of IFIT measurements on a per-service and on-demand basis. 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 12 March 2023. Fioccola, et al. Expires 12 March 2023 [Page 1] Internet-Draft BGP for IFIT Capability September 2022 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4 1.2. Definitions and Acronyms . . . . . . . . . . . . . . . . 4 2. IFIT Domain . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. IFIT Capabilities . . . . . . . . . . . . . . . . . . . . . . 5 4. BGP Next-Hop IFIT Capability Advertisement . . . . . . . . . 6 5. IFIT Attribute Operation . . . . . . . . . . . . . . . . . . 7 6. Head-to-Tail and Hop-by-Hop Mechanisms . . . . . . . . . . . 7 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 8. Security Considerations . . . . . . . . . . . . . . . . . . . 8 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 8 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 11.1. Normative References . . . . . . . . . . . . . . . . . . 9 11.2. Informative References . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction In-situ Flow Information Telemetry (IFIT) denotes a family of flow- oriented on-path telemetry techniques, including In-situ OAM (IOAM) [RFC9197] and Alternate Marking [I-D.ietf-ippm-rfc8321bis]. It can provide flow information on the entire forwarding path on a per- packet basis in real time. Fioccola, et al. Expires 12 March 2023 [Page 2] Internet-Draft BGP for IFIT Capability September 2022 IFIT is a solution focusing on network domains according to [RFC8799] that introduces the concept of specific domain solutions. A network domain consists of a set of network devices or entities within a single administration. As mentioned in [RFC8799], for a number of reasons, such as policies, options supported, style of network management and security requirements, it is suggested to limit applications including the emerging IFIT techniques to a controlled domain. Hence, the family of emerging on-path flow telemetry techniques MUST be typically deployed in such controlled domains. The IFIT solution MAY be selectively or partially implemented in different vendors' devices as an emerging feature for various use cases of application- aware network operations. In addition, for some use cases, the IFIT are deployed on a per-service and on-demand basis. This document introduces extensions to Border Gateway Protocol (BGP) to advertise the supported IFIT capabilities of the egress node to the ingress node in an IFIT domain when the egress node distributes a route, such as EVPNv4, EVPNv6, L2EVPN(EVPN VPWS and EVPN VPLS) routes, etc. Then the ingress node can learn the IFIT node capabilities associated to the routing information distributed between BGP peers and determine whether a particular IFIT Option type can be encapsulated in traffic packets which are forwarded along the path. Such advertisement would be useful for avoiding IFIT data leaking from the IFIT domain and measuring performance metrics on a per-service basis through steering packets of flow into a path where IFIT application are supported. This document defines an IFIT Next-Hop Capability Attribute according to [I-D.ietf-idr-next-hop-capability]. It allows a distributed solution that does not require the participation of centralized control element, while [I-D.ietf-idr-sr-policy-ifit] allows to centrally distribute Segment Routing (SR) Policies and can be considered as a centralized control solution. Therefore, this document enables the IFIT application in networks where no controller is introduced and it helps network operators to deploy IFIT in their networks. Since BGP can be used to advertise a candidate path of a SR Policy ([I-D.ietf-idr-segment-routing-te-policy]), in a SR network it may be convenient to advertise IFIT capabilities in BGP as well, as specified in this document. While, in other scenarios, ICMPv6 can also be an alternative solution ([I-D.ietf-ippm-ioam-conf-state]). Fioccola, et al. Expires 12 March 2023 [Page 3] Internet-Draft BGP for IFIT Capability September 2022 1.1. 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], RFC 8174 [RFC8174]. 1.2. Definitions and Acronyms * IFIT: In-situ Flow Information Telemetry. This term refers to the on-path telemetry techniques also known as In-situ OAM (IOAM) [RFC9197] and Alternate Marking [I-D.ietf-ippm-rfc8321bis]. * OAM: Operation Administration and Maintenance * NLRI: Network Layer Reachable Information, the NLRI advertised in the BGP UPDATE as defined in [RFC4271] and [RFC4760]. 2. IFIT Domain IFIT deployment modes can include monitoring at node-level, tunnel- level, and service-level. The requirement of this document is to provide IFIT deployment at service-level, since different services may have different IFIT requirements. With the service-level solution, different IFIT methods can be deployed for different VPN services. The figure shows an implementation example of IFIT application in a VPN scenario. +----+ +----+ +----+ | | +----+ | | +----+ |CE1 |------|PE1 |==========|RR/P|==========|PE2 |------|CE2 | +----+ | | +----+ | | +----+ +----+ +----+ |<------------IFIT Domain--------->| |<---------------BGP-------------->| |<----------------------------VPN--------------------------->| Figure 1. Example of IFIT application in a VPN scenario As the figure shows, a traffic flow is sent out from the customer edge node CE1 to another customer edge node CE2. In order to enable IFIT application for this flow, the IFIT header must be encapsulated in the packet at the ingress provider edge node PE1, referred to as the IFIT encapsulating node. Then, transit nodes in the IFIT domain may be able to support the IFIT capabilities in order to inspect IFIT Fioccola, et al. Expires 12 March 2023 [Page 4] Internet-Draft BGP for IFIT Capability September 2022 extensions and, if needed, to update the IFIT data fields in the packet. Finally, the IFIT data fields must be exported and removed at egress provider edge node PE2 that is referred to as the IFIT decapsulating node. This is essential to avoid IFIT data leakage outside the controlled domain. Since the IFIT decapsulating node MUST be able to handle and remove the IFIT header, the IFIT encapsulating node MUST know if the IFIT decapsulating node supports the IFIT application and, more specifically, which capabilities can be enabled. 3. IFIT Capabilities This document defines the IFIT Capabilities formed of a 32-bit bitmap. The following format is used: 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 +-+-+-+-+-+----------------------------------------------------+ |P|I|D|E|M| Reserved | +-+-+-+-+-+----------------------------------------------------+ Figure 2. IFIT Capabilities * P-Flag: IOAM Pre-allocated Trace Option Type flag. When set, this indicates that the router is capable of IOAM Pre-allocated Trace [RFC9197]. * I-Flag: IOAM Incremental Trace Option Type flag. When set, this indicates that the router is capable of IOAM Incremental Tracing [RFC9197]. * D-Flag: IOAM DEX Option Type flag. When set, this indicates that the router is capable of IOAM DEX [I-D.ioamteam-ippm-ioam-direct-export]. * E-Flag: IOAM E2E Option Type flag. When set, this indicates that the router is capable of IOAM E2E processing [RFC9197]. * M-Flag: Alternate Marking flag. When set, this indicates that the router is capable of processing Alternative Marking packets Alternate Marking [I-D.ietf-ippm-rfc8321bis]. * Reserved: Reserved for future use. They MUST be set to zero upon transmission and ignored upon receipt. Fioccola, et al. Expires 12 March 2023 [Page 5] Internet-Draft BGP for IFIT Capability September 2022 4. BGP Next-Hop IFIT Capability Advertisement The BGP Next-Hop Capability Attribute [I-D.ietf-idr-next-hop-capability] is a non-transitive BGP attribute and consists of a set of Next-Hop Capabilities. It is modified or deleted when the next-hop is changed, to reflect the capabilities of the new next-hop. The IFIT Capabilities described above can be encoded as a BGP Next- Hop IFIT Capability Attribute. It can be included in a BGP UPDATE message and indicates that the BGP Next-Hop supports the IFIT capability for the NLRI advertised in this BGP UPDATE. The IFIT Next-Hop Capability is defined below and is a triple (Capability Code, Capability Length, Capability Value) aka a 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Capability Code (TBA1) | Capability Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IFIT Capabilities | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ORIG. IP Address(4/16 octets) | | ... | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3. BGP Next-Hop Capability * Capability Code: a two-octets unsigned binary integer which indicates the type of "Next-Hop Capability" advertised and unambiguously identifies an individual capability. This document defines a new Next-Hop Capability, which is called IFIT Next-Hop Capability. The Capability Code is TBA1. * Capability Length: a two-octets unsigned binary integer which indicates the length, in octets, of the Capability Value field. A length of 0 indicates that no Capability Value field is present. * IFIT Capabilities: as defined in previous section. It should be reserved in [I-D.ietf-idr-next-hop-capability]. * ORIG. IP Address: An IPv4 or IPv6 Address of the IFIT decapsulation node. It is an IPv4 or IPv6 unicast address assigned by one of the Internet registries. Fioccola, et al. Expires 12 March 2023 [Page 6] Internet-Draft BGP for IFIT Capability September 2022 5. IFIT Attribute Operation A BGP speaker that sends an UPDATE with the BGP Next-Hop Capability Attribute MAY include the IFIT Next-Hop Capability, if IFIT is configured and enabled. The inclusion of the IFIT Next-Hop Capability with the NLRI advertised in the BGP UPDATE indicates that the BGP Next-Hop can act as the IFIT decapsulating node and it can process the specific IFIT encapsulation format indicated in the capability value. This is applied for all routes indicated in the same NRLI. The IFIT Next-Hop capability MUST reflect the capability of the router indicated in the BGP Next-Hop. If a BGP speaker sets the BGP Next-Hop to an address of a different router, it MUST NOT advertise the IFIT Next-Hop Capability not supported by this router. Therefore the IFIT capability MUST be re-advertised according to the new BGP Next-Hop. In case of large networks, the IFIT domain may span across multiple Autonomous Systems (ASes) and hence the IFIT capability need to be able to cross AS boundaries if configured to do so. In this case, it is also possible to pass this information between BGP clusters to keep the IFIT methods consistent. BGP Link-State (BGP-LS) may allow to bring the information back to a centralized controller as well. 6. Head-to-Tail and Hop-by-Hop Mechanisms When all devices are upgraded to support IFIT, the hop-by-hop mechanism can also be suitable. In the current stage, where new and old devices are deployed together, it is necessary to ensure that the tail node can properly decapsulate the IFIT header, so it is needed an advertisement mechanism from the head node to the tail node. Further, different services on the egress node may have different IFIT requirements, so the capability advertisement from the head node to the tail node is always required. However, it is worth noting that, once defined, hop-by-hop and head- to-tail mechanisms can eventually be used together without conflict. 7. IANA Considerations The IANA is requested to make the assignments for IFIT Next-Hop Capability: Fioccola, et al. Expires 12 March 2023 [Page 7] Internet-Draft BGP for IFIT Capability September 2022 +=======+===================+===============+ | Value | Description | Reference | +=======+===================+===============+ | TBA1 | IFIT Capabilities | This document | +-------+-------------------+---------------+ Table 1 8. Security Considerations This document defines extensions to BGP Next-Hop Capability to advertise the IFIT capabilities. It does not introduce any new security risks to BGP, as also mentioned in [I-D.ietf-idr-next-hop-capability]. IFIT methods are applied within a controlled domain and solutions MUST be taken to ensure that the IFIT data are properly propagated to avoid malicious attacks. Both IOAM method [RFC9197] and Alternate Marking method [I-D.ietf-6man-ipv6-alt-mark] respectively discussed that the implementation of both methods MUST be within a controlled domain. 9. Contributors The following people made significant contributions to this document: Yali Wang Huawei Email: wangyali11@huawei.com Yunan Gu Huawei Email: guyunan@huawei.com Tianran Zhou Huawei Email: zhoutianran@huawei.com Weidong Li Huawei Email: poly.li@huawei.com 10. Acknowledgements The authors would like to thank Ketan Talaulikar, Haoyu Song, Jie Dong, Robin Li, Jeffrey Haas, Robert Raszuk, Zongpeng Du, Yisong Liu, Yongqing Zhu, Aijun Wang, Fan Yang for their reviews and suggestions. Fioccola, et al. Expires 12 March 2023 [Page 8] Internet-Draft BGP for IFIT Capability September 2022 11. References 11.1. Normative References [I-D.ietf-6man-ipv6-alt-mark] Fioccola, G., Zhou, T., Cociglio, M., Qin, F., and R. Pang, "IPv6 Application of the Alternate Marking Method", Work in Progress, Internet-Draft, draft-ietf-6man-ipv6- alt-mark-16, 1 July 2022, . [I-D.ietf-idr-next-hop-capability] Decraene, B., Kompella, K., and W. Henderickx, "BGP Next- Hop dependent capabilities", Work in Progress, Internet- Draft, draft-ietf-idr-next-hop-capability-08, 8 June 2022, . [I-D.ietf-idr-segment-routing-te-policy] Previdi, S., Filsfils, C., Talaulikar, K., Mattes, P., Jain, D., and S. Lin, "Advertising Segment Routing Policies in BGP", Work in Progress, Internet-Draft, draft- ietf-idr-segment-routing-te-policy-20, 27 July 2022, . [I-D.ietf-idr-sr-policy-ifit] Qin, F., Yuan, H., Yang, S., Zhou, T., and G. Fioccola, "BGP SR Policy Extensions to Enable IFIT", Work in Progress, Internet-Draft, draft-ietf-idr-sr-policy-ifit- 04, 7 July 2022, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC9197] Brockners, F., Ed., Bhandari, S., Ed., and T. Mizrahi, Ed., "Data Fields for In Situ Operations, Administration, and Maintenance (IOAM)", RFC 9197, DOI 10.17487/RFC9197, May 2022, . Fioccola, et al. Expires 12 March 2023 [Page 9] Internet-Draft BGP for IFIT Capability September 2022 11.2. Informative References [I-D.ietf-ippm-ioam-conf-state] Min, X., Mirsky, G., and L. Bo, "Echo Request/Reply for Enabled In-situ OAM Capabilities", Work in Progress, Internet-Draft, draft-ietf-ippm-ioam-conf-state-04, 6 July 2022, . [I-D.ietf-ippm-rfc8321bis] Fioccola, G., Cociglio, M., Mirsky, G., Mizrahi, T., and T. Zhou, "Alternate-Marking Method", Work in Progress, Internet-Draft, draft-ietf-ippm-rfc8321bis-03, 25 July 2022, . [I-D.ioamteam-ippm-ioam-direct-export] Song, H., Gafni, B., Zhou, T., Li, Z., Brockners, F., Bhandari, S., Sivakolundu, R., and T. Mizrahi, "In-situ OAM Direct Exporting", Work in Progress, Internet-Draft, draft-ioamteam-ippm-ioam-direct-export-00, 12 October 2019, . [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, . [RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter, "Multiprotocol Extensions for BGP-4", RFC 4760, DOI 10.17487/RFC4760, January 2007, . [RFC8799] Carpenter, B. and B. Liu, "Limited Domains and Internet Protocols", RFC 8799, DOI 10.17487/RFC8799, July 2020, . Authors' Addresses Giuseppe Fioccola Huawei Munich Germany Email: giuseppe.fioccola@huawei.com Fioccola, et al. Expires 12 March 2023 [Page 10] Internet-Draft BGP for IFIT Capability September 2022 Ran Pang China Unicom Beijing China Email: pangran@chinaunicom.cn Subin Wang China Telecom Guangzhou China Email: wangsb6@chinatelecom.cn Bruno Decraene Orange Email: bruno.decraene@orange.com Shunwan Zhuang Huawei Beijing China Email: zhuangshunwan@huawei.com Hiabo Wang Huawei Beijing China Email: rainsword.wang@huawei.com Fioccola, et al. Expires 12 March 2023 [Page 11]