Bit Indexed Explicit Replication (bier) Internet Drafts

      
 BGP Extensions for BIER
 
 draft-ietf-bier-idr-extensions-19.txt
 Date: 19/12/2024
 Authors: Xiaohu Xu, Mach Chen, Keyur Patel, IJsbrand Wijnands, Tony Przygienda, Zhaohui Zhang
 Working Group: Bit Indexed Explicit Replication (bier)
 Bit Index Explicit Replication (BIER) is a multicast forwarding architecture that doesn't require an explicit tree-building protocol and doesn't require intermediate routers to maintain per-tree multicast states. Some BIER-specific information and state, which are only in proportion to the number of BIER routers but not per- tree, do need to be advertised, calculated, and maintained. This document describes BGP extensions for advertising the BIER information and methods for calculating BIER states based on the advertisements.
 Operations,Administration and Maintenance (OAM) Requirements for Bit Index Explicit Replication (BIER) Layer
 
 draft-ietf-bier-oam-requirements-16.txt
 Date: 04/11/2024
 Authors: Greg Mirsky, Nagendra Nainar, Mach Chen, Santosh Pallagatti
 Working Group: Bit Indexed Explicit Replication (bier)
 This document describes a list of functional requirements toward Operations, Administration and Maintenance (OAM) toolset in Bit Index Explicit Replication (BIER) layer of a network.
 Performance Measurement (PM) with Marking Method in Bit Index Explicit Replication (BIER) Layer
 
 draft-ietf-bier-pmmm-oam-16.txt
 Date: 07/11/2024
 Authors: Greg Mirsky, Lianshu Zheng, Mach Chen, Giuseppe Fioccola
 Working Group: Bit Indexed Explicit Replication (bier)
 This document describes the applicability of a hybrid performance measurement method for packet loss and packet delay measurements of a multicast service through a Bit Index Explicit Replication domain.
 BIER Ping and Trace
 
 draft-ietf-bier-ping-15.txt
 Date: 08/11/2024
 Authors: Nagendra Nainar, Carlos Pignataro, Mach Chen, Greg Mirsky
 Working Group: Bit Indexed Explicit Replication (bier)
 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 bit-string 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 describes the mechanism and basic BIER OAM packet format that can be used to perform failure detection and isolation on the BIER data plane.
 YANG Data Model for BIER Protocol
 
 draft-ietf-bier-bier-yang-10.txt
 Date: 11/02/2025
 Authors: Ran Chen, fangwei hu, Zheng Zhang, dai.xianxian@zte.com.cn, Mahesh Sivakumar
 Working Group: Bit Indexed Explicit Replication (bier)
 This document defines a YANG data model that can be used to configure and manage devices supporting Bit Index Explicit Replication"(BIER). The YANG module in this document conforms to the Network Management Datastore Architecture (NMDA).
 BGP Link-State extensions for BIER
 
 draft-ietf-bier-bgp-ls-bier-ext-19.txt
 Date: 12/10/2024
 Authors: Ran Chen, Zhaohui Zhang, Vengada Govindan, IJsbrand Wijnands
 Working Group: Bit Indexed Explicit Replication (bier)
 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. BGP Link-State (BGP-LS) enables the collection of various topology informations from the network, and the topology informations are used by the controller to calculate the fowarding tables and then propagate them onto the BFRs(instead of having each node to calculate on its own) and that can be for both inter-as and intra-as situations. This document specifies extensions to the BGP Link-state address- family in order to advertise the BIER informations.
 PIM Signaling Through BIER Core
 
 draft-ietf-bier-pim-signaling-13.txt
 Date: 03/03/2025
 Authors: Hooman Bidgoli, Fengman Xu, Jayant Kotalwar, IJsbrand Wijnands, Mankamana Mishra, Zhaohui Zhang
 Working Group: Bit Indexed Explicit Replication (bier)
 Consider large networks deploying traditional PIM multicast service. Typically, each portion of these large networks have their own mandates and requirements. It might be desirable to deploy BIER technology in some part of these networks to replace traditional PIM services. In such cases downstream PIM states need to be signaled over the BIER Domain toward the source. This document specifies the procedures to signal PIM Join and Prune messages through a BIER Domain using [RFC9739] , enabling the provisioning of traditional PIM services through a BIER Domain. These procedures are valid for forwarding PIM Join/Prune messages to the Source (SSM) or Rendezvous Point (ASM).
 BIER Penultimate Hop Popping
 
 draft-ietf-bier-php-16.txt
 Date: 04/12/2024
 Authors: Zhaohui Zhang
 Working Group: Bit Indexed Explicit Replication (bier)
 This document specifies a mechanism for Penultimate Hop Popping (PHP) in the Bit Index Explicit Replication (BIER) architecture. PHP enables the removal of the BIER header by the penultimate router, thereby reducing the processing burden on the final router in the delivery path. This extension to BIER enhances operational efficiency by optimizing packet forwarding in scenarios where the final hop's capabilities or requirements necessitate such handling. The document details the necessary extensions to the BIER encapsulation and forwarding processes to support PHP, providing guidance for implementation and deployment within BIER-enabled networks.
 A YANG data model for Tree Engineering for Bit Index Explicit Replication (BIER-TE)
 
 draft-ietf-bier-te-yang-08.txt
 Date: 20/01/2025
 Authors: Zheng Zhang, Cui(Linda) Wang, Ran Chen, fangwei hu, Mahesh Sivakumar, chenhuanan
 Working Group: Bit Indexed Explicit Replication (bier)
 This document defines a YANG data module for Tree Engineering for Bit Index Explicit Replication (BIER-TE) configuration and operation.
 BIER Prefix Redistribute
 
 draft-ietf-bier-prefix-redistribute-08.txt
 Date: 23/02/2025
 Authors: Zheng Zhang, Bo Wu, Zhaohui Zhang, IJsbrand Wijnands, Yisong Liu, Hooman Bidgoli
 Working Group: Bit Indexed Explicit Replication (bier)
 This document defines a BIER proxy function to support one single BIER sub-domain over multiple underlay routing protocol regions (Autonomous Systems or IGP areas). A new BIER proxy range sub-TLV is defined to redistribute BIER BFR-id information across the routing regions.
 Tethering A BIER Router To A BIER Incapable Router
 
 draft-ietf-bier-tether-08.txt
 Date: 03/12/2024
 Authors: Zhaohui Zhang, Nils Warnke, IJsbrand Wijnands, Daniel Awduche
 Working Group: Bit Indexed Explicit Replication (bier)
 This document specifies optional enhancements to optimize the support of Bit Index Explicit Replication (BIER) incapable routers in a BIER domain by attaching (tethering) a BIER router to a BIER incapable router, including procedures and ISIS/OSPF/BGP signaling extensions.
 M-LDP Signaling Through BIER Core
 
 draft-ietf-bier-mldp-signaling-over-bier-04.txt
 Date: 05/02/2025
 Authors: Hooman Bidgoli, IJsbrand Wijnands, Mankamana Mishra, Zhaohui Zhang, Eddie Leyton
 Working Group: Bit Indexed Explicit Replication (bier)
 Consider an end-to-end Multipoint LDP (mLDP) network, where it is desirable to deploy BIER in a segment of this network. It might be desirable to deploy BIER with minimal disruption to the mLDP network or a redesign of the network. This document describes a procedure needed for mLDP tunnels to be signaled over and stitched through a BIER core, allowing LDP routers to run traditional mLDP services through a BIER core.
 BIER BFD
 
 draft-ietf-bier-bfd-08.txt
 Date: 26/02/2025
 Authors: Quan Xiong, Greg Mirsky, fangwei hu, Chang Liu, Gyan Mishra
 Working Group: Bit Indexed Explicit Replication (bier)
 Point to multipoint (P2MP) BFD is designed to verify multipoint connectivity. This document specifies the application of P2MP BFD in BIER network.
 BIER (Bit Index Explicit Replication) Redundant Ingress Router Failover
 
 draft-ietf-bier-source-protection-08.txt
 Date: 27/03/2025
 Authors: Zheng Zhang, Greg Mirsky, Quan Xiong, Yisong Liu, Huanan Li
 Working Group: Bit Indexed Explicit Replication (bier)
 This document describes a failover in the Bit Index Explicit Replication domain with a redundant ingress router.
 Supporting BIER in IPv6 Networks (BIERin6)
 
 draft-ietf-bier-bierin6-11.txt
 Date: 02/03/2025
 Authors: Zheng Zhang, Zhaohui Zhang, IJsbrand Wijnands, Mankamana Mishra, Hooman Bidgoli, Gyan Mishra
 Working Group: Bit Indexed Explicit Replication (bier)
 BIER is a multicast forwarding architecture that does not require per-flow state inside the network yet still provides optimal replication. This document describes how the existing BIER encapsulation specified in RFC 8296 works in a non-MPLS IPv6 network, which is referred to as BIERin6. Specifically, like in an IPv4 network, BIER can work over L2 links directly or over tunnels. In case of IPv6 tunneling, a new IP "Next Header" type is to be assigned for BIER.
 BIER Fast ReRoute
 
 draft-ietf-bier-frr-07.txt
 Date: 24/02/2025
 Authors: Huaimo Chen, Mike McBride, Steffen Lindner, Michael Menth, Aijun Wang, Gyan Mishra
 Working Group: Bit Indexed Explicit Replication (bier)
 This document describes a mechanism for Fast Reroute (FRR) in Bit Index Explicit Replication (BIER) networks. The proposed solution enhances the resiliency of BIER by providing a method to quickly reroute traffic in the event of a link or node failure, thereby minimizing packet loss and service disruption. The document details the procedures for detecting failures and selecting backup paths within the BIER domain, ensuring that multicast traffic continues to reach its intended destinations without requiring per-flow state or additional signaling. This FRR mechanism is designed to integrate seamlessly with existing BIER operations, offering a robust solution for improving network reliability.

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Bit Indexed Explicit Replication (bier)

WG Name Bit Indexed Explicit Replication
Acronym bier
Area Routing Area (rtg)
State Active
Charter charter-ietf-bier-03 Approved
Document dependencies
Additional resources Wiki, Zulip Stream
Personnel Chairs Greg Shepherd, Tony Przygienda
Area Director Gunter Van de Velde
Delegates Jeff Tantsura, Zheng Zhang
Secretary Zheng Zhang
Mailing list Address bier@ietf.org
To subscribe https://www.ietf.org/mailman/listinfo/bier
Archive https://mailarchive.ietf.org/arch/browse/bier/
Chat Room address https://zulip.ietf.org/#narrow/stream/bier

Charter for Working Group

The BIER (Bit Index Explicit Replication) Working Group has defined an architecture [RFC 8279] for a dedicated multi-point forwarding plane that can use a variety of encapsulations. Current encapsulation specifications are [RFC 8296] that can be used on MPLS or Ethernet transport, which has received an Ethertype assignment [0xAB37] from the IEEE. In addition, the WG has adopted draft-ietf-bier-bierin6 to progress as a proposed standard solution for native IPv6 encapsulation in coordination with the 6MAN and OPSAWG working groups. The BIER-WG is chartered to produce Standards Track, Informational, Best Current Practices, and Experimental RFCs, including the status update for RFCs 8279 and 8296. Some Informational drafts may be published, others may progress through WGLC but not be published.

The focus of the BIER-WG is on deployment: transition, partial deployments, applicability and management.

First and primarily, the BIER-WG will complete its work on:

1) Transition Mechanisms and Partial Deployments: The WG will define mechanisms to integrate BIER into existing multicast networks, enabling partial or end-to-end adoption alongside protocols like PIM and various MVPN solutions, addressing scenarios with non-BIER-capable routers, mixed BitStringLengths, and varying encapsulations. This includes connecting legacy multicast non-BIER domains over a BIER core, the mixing of BIER-capable routers with non-BIER routers within the same domain, and introducing BIER-only replication points as part of a legacy multicast network. This work is to include all connection and transition mechanisms to be specified. (Intended status: Experimental, Informational or Proposed Standard).

2) Applicability Statements: Building on prior work (e.g., MVPN [RFC 8556], EVPN/BUM [RFC 9624]), the WG will continue developing applicability statements to articulate BIER’s use in specific scenarios. (Intended status: Informational).

3) Use Case Documentation: The WG will produce a comprehensive use-case document ([draft-ietf-bier-use-cases]) highlighting the benefits of BIER across different applications. (Intended status: Informational).

4) Operations, Administration, and Maintenance (OAM): The WG will specify mechanisms for OAM within BIER domains, emphasizing extensions to existing protocols and documenting maintenance simplifications ([draft-ietf-bier-oam-requirements]). (Intended status: Informational (for requirements) and Proposed Standard (for extensions to existing protocols).

5) Manageability: Define manageability considerations for BIER, such as the development of YANG modules for BIER, as captured in [draft-ietf-bier-bier-yang], will be prioritized to standardize management practices. (Intended status: Proposed Standard).

6) Link-State Routing and BGP Extensions: The WG will specify extensions for OSPFv3 ([draft-ietf-bier-ospfv3-extensions]) and explore additional IGP extensions for constrained topologies. Cooperation with LSR, IDR, and BESS will ensure alignment with related BGP and IGP efforts. (Intended status: Proposed Standard).

7) Forwarding Plane Mechanisms for BIER Traffic Engineering: The WG will define forwarding plane structures (e.g., BIFT) for engineered multicast trees, excluding PCE work. (Intended status: Proposed Standard).

8) Extending BIER scalability: The WG will address scalability requirements and solutions for BIER replication, using ( [draft-zzhang-bier-unmasked-bier]) as a reference draft starting point. (Intended status: Experimental).

Additionally, the WG will coordinate with related working groups, including MPLS, LSR, BABEL, BESS, IDR, PIM, MBONED, PCE, and TEAS, to ensure alignment and interoperability in areas such as OAM, routing extensions, multicast membership management, and architecture for BIER-TE forwarding. These collaborations will support the advancement of BIER as a scalable and efficient solution for multicast forwarding.

This charter reflects the commitment of the BIER-WG to provide practical, interoperable, and standardized mechanisms for BIER in modern networks.

Milestones

Date Milestone Associated documents
Dec 2025 Complete BIER YANG drafts to progress to WGLC draft-ietf-bier-bier-yang
Dec 2025 Update BIER use cases draft to reflect new work and deployment experience draft-ietf-bier-use-cases
Jul 2025 (new draft) Continue work on BIER scalability solutions
Jul 2025 Complete BIER IGMPv3 Extension draft to progress to WGLC draft-ietf-bier-mld
Jul 2025 Complete BIER OAM requirements draft to progress to WGLC draft-ietf-bier-oam-requirements
Jul 2025 (new draft) Introduce BIER Transitions draft to function as a guideline for the WG