Networking Working Group Ran. Chen Internet-Draft Zheng. Zhang Intended status: Standards Track ZTE Corporation Expires: January 31, 2018 Vengada. Govindan IJsbrand. Wijnands Cisco July 30, 2017 BGP Link-State extensions for BIER draft-ietf-bier-bgp-ls-bier-ext-01 Abstract Bit Index Explicit Replication (BIER) is an architecture that provides optimal multicast forwarding through a "BIER domain" without requiring intermediate routers to maintain any multicast related per- flow state. BIER also does not require any explicit tree-building protocol for its operation. A multicast data packet enters a BIER domain at a "Bit-Forwarding Ingress Router" (BFIR), and leaves the BIER domain at one or more "Bit-Forwarding Egress Routers" (BFERs). The BFIR router adds a BIER header to the packet. The BIER header contains a bitstring in which each bit represents exactly one BFER to forward the packet to. The set of BFERs to which the multicast packet needs to be forwarded is expressed by setting the bits that correspond to those routers in the BIER header. This document specifies extensions to the BGP Link-state address- family in order to advertising BIER information. 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 http://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 January 31, 2018. Chen, et al. Expires January 31, 2018 [Page 1] Internet-Draft BGP-LS extensions for BIER July 2017 Copyright Notice Copyright (c) 2017 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 (http://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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions used in this document . . . . . . . . . . . . . . 3 3. BGP-LS Extensions for BIER . . . . . . . . . . . . . . . . . 3 3.1. The BIER TLV . . . . . . . . . . . . . . . . . . . . . . 3 3.1.1. The BIER MPLS Encapsulation Sub-TLV . . . . . . . . . 4 3.2. The BIER-TE TLV . . . . . . . . . . . . . . . . . . . . . 5 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 7. Normative references . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction Bit Index Explicit Replication (BIER) is an architecture that provides optimal multicast forwarding through a "BIER domain" without requiring intermediate routers to maintain any multicast related per- flow state. BIER also does not require any explicit tree-building protocol for its operation. A multicast data packet enters a BIER domain at a "Bit-Forwarding Ingress Router" (BFIR), and leaves the BIER domain at one or more "Bit-Forwarding Egress Routers" (BFERs). The BFIR router adds a BIER header to the packet. The BIER header contains a bitstring in which each bit represents exactly one BFER to forward the packet to. The set of BFERs to which the multicast packet needs to be forwarded is expressed by setting the bits that correspond to those routers in the BIER header. This document specifies extensions to the BGP Link-state address- family in order to advertising BIER-specific. An external component (e.g., a controller) then can collect BIER information in the "northbound" direction within the BIER domain. Chen, et al. Expires January 31, 2018 [Page 2] Internet-Draft BGP-LS extensions for BIER July 2017 2. Conventions used in this document 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 RFC2119. 3. BGP-LS Extensions for BIER Each BFR MUST be assigned a "BFR-Prefix". A BFR's BFR-Prefix MUST be an IP address (either IPv4 or IPv6) of the BFR, and MUST be unique and routable within the BIER domain as described in section 2 of [I-D.ietf-bier-architecture], and then external component (e.g., a controller) need to collect BIER information of BIER routers are associated with the BFR-Prefix in the "northbound" direction within the BIER domain. Given that the BIER information is associated with the prefix, the BGP-LS Prefix Attribute TLV [I-D.ietf-idr-ls-distribution] can be used to carry the BIER information. A new Prefix Attribute TLV and Sub-TLV are defined for the encoding of BIER information. 3.1. The BIER TLV A new Prefix Attribute TLV (defined in [I-D.ietf-idr-ls-distribution] is defined for distributing BIER information. The new TLV is called the BIER TLV. The BIER TLVs may appear multiple times. The following BIER TLV is defined: 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 | subdomain-id | MT-ID | BSL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BFR-id | reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sub-TLVs (variable) | +- -+ | | Figure 1 Type:as indicated in IANA Considerations section. Chen, et al. Expires January 31, 2018 [Page 3] Internet-Draft BGP-LS extensions for BIER July 2017 Length: 2 octet. Reserved: MUST be 0 on transmission, ignored on reception. May be used in future versions. Subdomain-id: Unique value identifying the BIER sub-domain, 1 octet. MT-ID: Multi-Topology ID that identifies the topology that is associated with the BIER sub-domain.1 octet. BitString Length (BS Len): A 1 octet field encoding the supported BitString length associated with this BFR-prefix.This field are specified in section 3 of [I-D.ietf-bier-mpls-encapsulation].Given that the bier router can support BSL values set, this field encoding the BSL values set that BIER routers supported. BFR-id: A 2 octet field encoding the BFR-id, as documented in [I-D.ietf-bier-architecture]. If the BFR-id is zero, it means, the advertising router is not advertising any BIER-id.In some environment, BFR-id can be configured by NMS, The BFR-id should be sent to a controller. If multiple BIER Sub-TLVs are present, all having the same BS Length and Subdomain-id values, first one MUST be used and subsequent ones MUST be ignored. 3.1.1. The BIER MPLS Encapsulation Sub-TLV The BIER MPLS Encapsulation Sub-TLV is a sub-TLV of the BIER TLV. BIER MPLS Encapsulation Sub-TLV is used in order to advertise MPLS specific information used for BIER. It MUST appear multiple times in the BIER TLV as described in [I-D.ietf-bier-ospf-bier-extensions] The following the BIER MPLS Encapsulation Sub-TLV is defined: 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Lbl Range Size | Label Range Base | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BS Length | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2 Chen, et al. Expires January 31, 2018 [Page 4] Internet-Draft BGP-LS extensions for BIER July 2017 Type: as indicated in IANA Considerations section. Length: 2 octet. Label Range Size: A 1 octet field encoding the label range size of the label range. It MUST be greater than 0, otherwise the TLV MUST be ignored. Label Range Base: A 3 octet field, where the 20 rightmost bits represent the first label in the label range. BS Length: Bitstring length for the label range that this router is advertising per [I-D.ietf-bier-mpls-encapsulation]. 1 octet.The values allowed in this field are specified in section 3 of [I-D.ietf-bier-mpls-encapsulation]. The "label range" is the set of labels beginning with the label range base and ending with (label range base)+(label range size)-1. A unique label range is allocated for each BitStream length and Sub- domain-ID. These label is used for BIER forwarding as described in [I-D.ietf-bier-architecture] and [I-D.ietf-bier-mpls-encapsulation].Label ranges within the sub-TLV MUST NOT overlap, otherwise the whole sub-TLV MUST be disregarded BS length in multiple BIER MPLS Encapsulation Sub-TLV inside the same BIER Sub-TLV MUST NOT repeat, otherwise only the first BIER MPLS Encapsulation Sub-TLV with such BS length MUST be used and any subsequent BIER MPLS Encapsulation Sub-TLVs with the same BS length MUST be ignored. 3.2. The BIER-TE TLV This TLV is used to collect BIER-TE information in the "northbound" direction within the BIER-TE domain. The section will be added in next version. 4. IANA Considerations This document requests assigning code-points from the registry for the new Prefix Attribute TLV and Sub-TLV. Chen, et al. Expires January 31, 2018 [Page 5] Internet-Draft BGP-LS extensions for BIER July 2017 +-------------------+---------------+-----------------+ | TLV Code Point | Description | Value defined | +-------------------+---------------+-----------------+ | 1158( recommend ) | BIER | this document | +-------------------+---------------+-----------------+ Table 1: The new Prefix Attribute TLV +-----------------+-------------------------------+-----------------+ | Sub-TLV | Description | Value | | Code Point | | | +-----------------+-------------------------------+-----------------+ | 1 ( recommend) | BIER MPLS Encapsulation | this document | +------------+-------------------------------+----------------------+ Table 2: The new Prefix Attribute Sub-TLV 5. Security Considerations Procedures and protocol extensions defined in this document do not affect the BGP security model. See [RFC6952] for details. 6. Acknowledgements We would like to thank Peter Psenak (Cisco) for his comments and support of this work. 7. Normative references [I-D.ietf-bier-architecture] Wijnands, I., Rosen, E., Dolganow, A., Przygienda, T., and S. Aldrin, "Multicast using Bit Index Explicit Replication", draft-ietf-bier-architecture-07 (work in progress), June 2017. [I-D.ietf-bier-isis-extensions] Ginsberg, L., Przygienda, T., Aldrin, S., and Z. Zhang, "BIER support via ISIS", draft-ietf-bier-isis- extensions-04 (work in progress), March 2017. Chen, et al. Expires January 31, 2018 [Page 6] Internet-Draft BGP-LS extensions for BIER July 2017 [I-D.ietf-bier-mpls-encapsulation] Wijnands, I., Rosen, E., Dolganow, A., Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation for Bit Index Explicit Replication in MPLS and non-MPLS Networks", draft-ietf-bier-mpls-encapsulation-07 (work in progress), June 2017. [I-D.ietf-bier-ospf-bier-extensions] Psenak, P., Kumar, N., Wijnands, I., Dolganow, A., Przygienda, T., Zhang, Z., and S. Aldrin, "OSPF Extensions for BIER", draft-ietf-bier-ospf-bier-extensions-07 (work in progress), July 2017. [I-D.ietf-idr-ls-distribution] Gredler, H., Medved, J., Previdi, S., Farrel, A., and S. Ray, "North-Bound Distribution of Link-State and TE Information using BGP", draft-ietf-idr-ls-distribution-13 (work in progress), October 2015. [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering (TE) Extensions to OSPF Version 2", RFC 3630, DOI 10.17487/RFC3630, September 2003, . [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, . Authors' Addresses Ran Chen ZTE Corporation No.50 Software Avenue,Yuhuatai District Nanjing, Jiangsu Province 210012 China Phone: +86 025 88014636 Email: chen.ran@zte.com.cn Chen, et al. Expires January 31, 2018 [Page 7] Internet-Draft BGP-LS extensions for BIER July 2017 Zheng Zhang ZTE Corporation No.50 Software Avenue,Yuhuatai District Nanjing, Jiangsu Province 210012 China Email: zhang.zheng@zte.com.cn Vengada Prasad Govindan Cisco Email: venggovi@cisco.com IJsbrand Wijnands Cisco De Kleetlaan 6a Diegem 1831 Belgium Email: ice@cisco.com Chen, et al. Expires January 31, 2018 [Page 8]