--- 1/draft-ietf-idr-sr-policy-path-mtu-00.txt 2020-04-28 04:13:13.253314798 -0700 +++ 2/draft-ietf-idr-sr-policy-path-mtu-01.txt 2020-04-28 04:13:13.349317254 -0700 @@ -3,21 +3,21 @@ Internet-Draft Huawei Technologies Intended status: Standards Track Y. Zhu Expires: October 30, 2020 China Telecom A. Sawaf Saudi Telecom Company Z. Li Huawei Technologies April 28, 2020 Segment Routing Path MTU in BGP - draft-ietf-idr-sr-policy-path-mtu-00 + draft-ietf-idr-sr-policy-path-mtu-01 Abstract Segment Routing is a source routing paradigm that explicitly indicates the forwarding path for packets at the ingress node. An SR policy is a set of candidate SR paths consisting of one or more segment lists with necessary path attributes. However, the path maximum transmission unit (MTU) information for SR path is not available in the SR policy since the SR does not require signaling. This document defines extensions to BGP to distribute path MTU @@ -54,30 +54,32 @@ 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 3. SR Policy for Path MTU . . . . . . . . . . . . . . . . . . . 3 - 3.1. SR Path MTU Sub-TLV . . . . . . . . . . . . . . . . . . . 4 + 3.1. Path MTU Sub-TLV . . . . . . . . . . . . . . . . . . . . 4 4. Operations . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 - 6. Security Considerations . . . . . . . . . . . . . . . . . . . 6 - 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 6 - 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 - 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 9.1. Normative References . . . . . . . . . . . . . . . . . . 6 - 9.2. Informative References . . . . . . . . . . . . . . . . . 7 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 + 5. Implementation Status . . . . . . . . . . . . . . . . . . . . 6 + 5.1. Huawei's Commercial Delivery . . . . . . . . . . . . . . 6 + 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 + 7. Security Considerations . . . . . . . . . . . . . . . . . . . 7 + 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 7 + 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 + 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 + 10.1. Normative References . . . . . . . . . . . . . . . . . . 7 + 10.2. Informative References . . . . . . . . . . . . . . . . . 8 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 1. Introduction Segment routing (SR) [RFC8402] is a source routing paradigm that explicitly indicates the forwarding path for packets at the ingress node. The ingress node steers packets into a specific path according to the Segment Routing Policy ( SR Policy) as defined in [I-D.ietf-spring-segment-routing-policy]. In order to distribute SR policies to the headend, [I-D.ietf-idr-segment-routing-te-policy] specifies a mechanism by using BGP. @@ -164,30 +166,40 @@ Policy Name Explicit NULL Label Policy (ENLP) Segment List Weight Path MTU Segment Segment ... ... -3.1. SR Path MTU Sub-TLV +3.1. Path MTU Sub-TLV - An SR Path MTU sub-TLV is an Optional sub-TLV. When it appears, it - must appear only once at most within a Segment List sub-TLV. If - multiple Path MTU sub-TLVs appear within a Segment List sub-TLV, the - first one will be processed, and the rest will be ignored. An SR - Path MTU sub-TLV is associated with an SR path specified by a segment - list sub-TLV or path segment as defined in - [I-D.ietf-spring-mpls-path-segment] and - [I-D.li-spring-srv6-path-segment]. It has the following format: + A Path MTU sub-TLV is an Optional sub-TLV. When it appears, it must + appear only once at most within a Segment List sub-TLV. If multiple + Path MTU sub-TLVs appear within a Segment List sub-TLV, the NLRI MUST + be treated as a malformed NLRI. + + As per [I-D.ietf-idr-segment-routing-te-policy], when the error + determined allows for the router to skip the malformed NLRI(s) and + continue processing of the rest of the update message, then it MUST + handle such malformed NLRIs as 'Treat-as-withdraw'. This document + does not define new error handling rules for Path MTU sub-TLV, and + the error handling rules defined in + [I-D.ietf-idr-segment-routing-te-policy] apply to this document. + + A Path MTU sub-TLV is associated with an SR path specified by a + segment list sub-TLV or a path segment + [I-D.ietf-spring-mpls-path-segment] + [I-D.li-spring-srv6-path-segment]. The Path MTU 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | RESERVED | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Path MTU | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1. Path MTU sub-TLV @@ -204,73 +216,113 @@ Path MTU: 4 bytes value of path MTU in octets. The value can be calculated by a central controller or other devices based on the information that learned via IGP of BGP-LS or other means. Whenever the path MTU of a physical or logical interface is changed, a new SR policy with new path MTU information should be updated accordingly by BGP. 4. Operations - The document does not bring new operation beyong the description of + The document does not bring new operation beyond the description of operations defined in [I-D.ietf-idr-segment-routing-te-policy]. The existing operations defined in [I-D.ietf-idr-segment-routing-te-policy] can apply to this document directly. Typically but not limit to, the SR policies carrying path MTU infomation are configured by a controller. After configuration, the SR policies carrying path MTU infomation will be advertised by BGP update messages. The operation of advertisement is the same as defined in [I-D.ietf-idr-segment-routing-te-policy], as well as the receiption. The consumer of the SR policies is not the BGP process. The operation of sending information to consumers is out of scope of this document. -5. IANA Considerations +5. Implementation Status + + [Note to the RFC Editor - remove this section before publication, as + well as remove the reference to [RFC7942]. + + This section records the status of known implementations of the + protocol defined by this specification at the time of posting of this + Internet-Draft, and is based on a proposal described in [RFC7942]. + The description of implementations in this section is intended to + assist the IETF in its decision processes in progressing drafts to + RFCs. Please note that the listing of any individual implementation + here does not imply endorsement by the IETF. Furthermore, no effort + has been spent to verify the information presented here that was + supplied by IETF contributors. This is not intended as, and must not + be construed to be, a catalog of available implementations or their + features. Readers are advised to note that other implementations may + exist. + + According to [RFC7942], "this will allow reviewers and working groups + to assign due consideration to documents that have the benefit of + running code, which may serve as evidence of valuable experimentation + and feedback that have made the implemented protocols more mature. + It is up to the individual working groups to use this information as + they see fit". + +5.1. Huawei's Commercial Delivery + + The feature has been implemented on Huawei VRP8. + + o Organization: Huawei + + o Implementation: Huawei's Commercial Delivery implementation based + on VRP8. + + o Description: The implementation has been done. + + o Maturity Level: Product + + o Contact: guokeqiang@huawei.com + +6. IANA Considerations This document defines a new Sub-TLV in registries "SR Policy List Sub- TLVs" [I-D.ietf-idr-segment-routing-te-policy]: Value Description Reference --------------------------------------------------------------------- TBA Path MTU sub-TLV This document -6. Security Considerations +7. Security Considerations TBA -7. Contributors +8. Contributors Jun Qiu Huawei Technologies China Email: qiujun8@huawei.com -8. Acknowledgements +9. Acknowledgements Authors would like to thank Ketan Talaulikar, Aijun Wang, Weiqiang Cheng, Huanan Chen, Chongfeng Xie, Stefano Previdi, Taishan Tang, Keqiang Guo, Chen Zhang, Susan Hares, Weiguo Hao, Gong Xia, Bing Yang, Linda Dunbar, Shunwan Zhuang, Huaimo Chen, Mach Chen, Jingring Xie, Zhibo Hu, Jimmy Dong and Jianwei Mao for their proprefessional comments and help. -9. References +10. References -9.1. Normative References +10.1. Normative References [I-D.ietf-idr-segment-routing-te-policy] Previdi, S., Filsfils, C., Talaulikar, K., Mattes, P., Rosen, E., Jain, D., and S. Lin, "Advertising Segment Routing Policies in BGP", draft-ietf-idr-segment-routing- te-policy-08 (work in progress), November 2019. [I-D.ietf-spring-segment-routing-policy] Filsfils, C., Sivabalan, S., Voyer, D., Bogdanov, A., and P. Mattes, "Segment Routing Policy Architecture", draft- @@ -284,21 +336,21 @@ [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [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, . -9.2. Informative References +10.2. Informative References [I-D.ietf-spring-mpls-path-segment] Cheng, W., Li, H., Chen, M., Gandhi, R., and R. Zigler, "Path Segment in MPLS Based Segment Routing Network", draft-ietf-spring-mpls-path-segment-02 (work in progress), February 2020. [I-D.li-spring-srv6-path-segment] Li, C., Cheng, W., Chen, M., Dhody, D., and R. Gandhi, "Path Segment for SRv6 (Segment Routing in IPv6)", draft- @@ -308,20 +360,25 @@ [I-D.zhu-idr-bgp-ls-path-mtu] Zhu, Y., Hu, Z., Yan, G., and J. Yao, "BGP-LS Extensions for Advertising Path MTU", draft-zhu-idr-bgp-ls-path- mtu-02 (work in progress), January 2020. [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, . + [RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running + Code: The Implementation Status Section", BCP 205, + RFC 7942, DOI 10.17487/RFC7942, July 2016, + . + [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", STD 86, RFC 8200, DOI 10.17487/RFC8200, July 2017, . [RFC8201] McCann, J., Deering, S., Mogul, J., and R. Hinden, Ed., "Path MTU Discovery for IP version 6", STD 87, RFC 8201, DOI 10.17487/RFC8201, July 2017, . @@ -334,21 +391,21 @@ China Email: chengli13@huawei.com YongQing Zhu China Telecom 109, West Zhongshan Road, Tianhe District. Guangzhou China - Email: zhuyq.gd@chinatelecom.cn + Email: zhuyq8@chinatelecom.cn Ahmed El Sawaf Saudi Telecom Company Riyadh Saudi Arabia Email: aelsawaf.c@stc.com.sa Zhenbin Li Huawei Technologies