BIER WG Z. Zhang Internet-Draft ZTE Corporation Intended status: Standards Track A. Przygienda Expires: December 29, 2017 Juniper Networks June 27, 2017 BIER in BABEL draft-zhang-bier-babel-extensions-01 Abstract BIER introduces a novel multicast architecture. It does not require a signaling protocol to explicitly build multicast distribution trees, nor does it require intermediate nodes to maintain any per- flow state. Babel defines a distance-vector routing protocol that operates in a robust and efficient fashion both in wired as well as in wireless mesh networks. This document defines a way to carry necessary BIER signaling information in Babel. 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 December 29, 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 Zhang & Przygienda Expires December 29, 2017 [Page 1]
Internet-Draft BIER Babel extensions June 2017 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. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Advertisement of BIER information . . . . . . . . . . . . . . 2 3.1. BIER BFR-prefix and BIER sub-TLV . . . . . . . . . . . . 3 3.1.1. BIER sub-TLV . . . . . . . . . . . . . . . . . . . . 3 3.2. BIER MPLS Encapsulation sub-sub-TLV . . . . . . . . . . . 3 3.3. Optional BIER sub-domain BSL conversion sub-sub-TLV . . . 4 4. Tree types and tunneling . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5 8. Normative References . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 1. Introduction [I-D.ietf-bier-architecture] introduces a novel multicast architecture. It does not require a signaling protocol to explicitly build multicast distribution trees, nor does it require intermediate nodes to maintain any per-flow state. All procedures necessary to support BIER are abbreviated by the "BIER architecture" moniker in this document. [RFC6126] and [I-D.ietf-babel-rfc6126bis] define a distance-vector routing protocol under the name of "Babel". Babel operates in a robust and efficient fashion both in ordinary wired as well as in wireless mesh networks. 2. Terminology The terminology of this documents follows [I-D.ietf-bier-architecture], [RFC6126], [RFC7557] and [I-D.ietf-babel-rfc6126bis]. 3. Advertisement of BIER information In case a router is configured with BIER information, and Babel is the routing protocol used, such a router MAY use Babel protocol to announce the BIER information using the BIER sub-TLV specified below. Zhang & Przygienda Expires December 29, 2017 [Page 2]
Internet-Draft BIER Babel extensions June 2017 3.1. BIER BFR-prefix and BIER sub-TLV BFR-prefix and according information is carried in a Babel Update TLV per [I-D.ietf-babel-rfc6126bis]. A new sub-TLV is defined to convey further BIER information such as BFR-id, sub-domain-id and BSL. Two sub-sub-TLVs are carried as payload of BIER sub-TLV. The mandatory bit of BIER sub-TLV should be set to 0. If a router cannot recognize a sub-TLV, the router MUST ignore this unknown sub- TLV. 3.1.1. BIER sub-TLV The BIER sub-TLV format aligns exactly with the definition and restrictions in [I-D.ietf-bier-isis-extensions] and [I-D.ietf-bier-ospf-bier-extensions]. It is a sub-TLV of Babel update TLV. The prefix MUST NOT be summarized and the according sub- TLV MUST be treated as optional and transitive. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | sub-Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | subdomain-id | BFR-id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: BIER sub-TLV o Type: as indicated in IANA section. o Length: 1 octet. Include the length of BIER sub-TLV and potential length of the two sub-sub-TLVs. o Reserved: MUST be 0 on transmission, ignored on reception. May be used in future versions. 8 bits. o subdomain-id: Unique value identifying the BIER sub-domain. 1 octet. o BFR-id: A 2 octet field encoding the BFR-id, as documented in [I-D.ietf-bier-architecture]. If no BFR-id has been assigned this field is set to the invalid BFR-id. 3.2. BIER MPLS Encapsulation sub-sub-TLV The BIER MPLS Encapsulation sub-sub-TLV can be carried by BIER sub- TLV. The format and restrictions are aligned with [I-D.ietf-bier-isis-extensions] and Zhang & Przygienda Expires December 29, 2017 [Page 3]
Internet-Draft BIER Babel extensions June 2017 [I-D.ietf-bier-ospf-bier-extensions]. This sub-sub-TLV carries the information for the BIER MPLS encapsulation including the label range for a specific BSL for a certain <MT,SD> pair. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | sub-sub-Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Lbl Range Size|BS Len | Label | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: MPLS Encapsulation sub-sub-TLV o Type: value of 1 indicating MPLS encapsulation. o Length: 1 octet o Local BitString Length (BS Len): Encoded bitstring length as per [I-D.ietf-bier-mpls-encapsulation]. 4 bits. o Label Range Size: Number of labels in the range for this BIER sub- domain and bitstring length combination, 1 octet. o Label: First label of the range, 20 bits. The labels are as defined in [I-D.ietf-bier-mpls-encapsulation]. 3.3. Optional BIER sub-domain BSL conversion sub-sub-TLV This sub-sub-TLV is used to carry the BSL information. Its definition and restrictions are aligned with [I-D.ietf-bier-isis-extensions]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | sub-sub-Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4: BSL conversion sub-sub-TLV 4. Tree types and tunneling Since Babel is performing a diffusion computation, support for different tree types is not as natural as with link-state protocols. Hence this specification is assuming that normal Babel reachability computation is performed without further modifications. Zhang & Przygienda Expires December 29, 2017 [Page 4]
Internet-Draft BIER Babel extensions June 2017 BIER architecture does not rely on all routers in a domain performing BFR procedures. How to support tunnels that will allow to tunnel BIER across such routers in Babel is for further study. 5. Security Considerations TBD 6. IANA Considerations A new type of Babel update sub-TLV needs to be defined for BIER information advertisement. 7. Acknowledgements The draft is aligned with the [I-D.ietf-bier-isis-extensions] and [I-D.ietf-bier-ospf-bier-extensions] as far as feasible. 8. Normative References [I-D.ietf-babel-rfc6126bis] Chroboczek, J., "The Babel Routing Protocol", draft-ietf- babel-rfc6126bis-02 (work in progress), May 2017. [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. [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-06 (work in progress), June 2017. Zhang & Przygienda Expires December 29, 2017 [Page 5]
Internet-Draft BIER Babel extensions June 2017 [RFC6126] Chroboczek, J., "The Babel Routing Protocol", RFC 6126, DOI 10.17487/RFC6126, April 2011, <http://www.rfc-editor.org/info/rfc6126>. [RFC7557] Chroboczek, J., "Extension Mechanism for the Babel Routing Protocol", RFC 7557, DOI 10.17487/RFC7557, May 2015, <http://www.rfc-editor.org/info/rfc7557>. Authors' Addresses Zheng(Sandy) Zhang ZTE Corporation No. 50 Software Ave, Yuhuatai Distinct Nanjing China Email: zhang.zheng@zte.com.cn Tony Przygienda Juniper Networks Email: prz@juniper.net Zhang & Przygienda Expires December 29, 2017 [Page 6]