Internet DRAFT - draft-zwx-bier-te-extensions

draft-zwx-bier-te-extensions







BIER                                                            Z. Zhang
Internet-Draft                                                    Y. Wei
Intended status: Standards Track                                   B. Xu
Expires: 6 March 2024                                    ZTE Corporation
                                                            IJ. Wijnands
                                                                  Arrcus
                                                        3 September 2023


 IS-IS and OSPF extensions for BIER-TE (Tree Engineering for Bit Index
       Explicit Replication) with MPLS and non-MPLS Encapsulation
                    draft-zwx-bier-te-extensions-03

Abstract

   This document describes the IS-IS and OSPF protocol extensions that
   are required for BIER-TE and RBS with MPLS and non-MPLS
   encapsulation.

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
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   This Internet-Draft will expire on 6 March 2024.

Copyright Notice

   Copyright (c) 2023 IETF Trust and the persons identified as the
   document authors.  All rights reserved.











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   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
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   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Flooding of the BIER-TE/RBS Encapsulation Information in
           IS-IS . . . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  BIER-TE MPLS Encapsulation Sub-sub-TLV  . . . . . . . . .   4
     3.2.  BIER-TE Non-MPLS Encapsulation Sub-sub-TLV  . . . . . . .   4
       3.2.1.  BIER-TE IPv6 Encapsulation sub-sub-sub-tlv  . . . . .   5
   4.  Flooding of the BIER-TE/RBS Encapsulation Information in
           OSPF  . . . . . . . . . . . . . . . . . . . . . . . . . .   6
     4.1.  BIER-TE MPLS Encapsulation Sub-TLV  . . . . . . . . . . .   6
     4.2.  BIER-TE Non-MPLS Encapsulation Sub-TLV  . . . . . . . . .   7
       4.2.1.  BIER-TE IPv6 Encapsulation sub-sub-tlv  . . . . . . .   8
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
     5.1.  IS-IS Sub-sub-TLVs for BIER Info sub-TLV Registry . . . .   8
     5.2.  OSPFv2 Extended Prefix TLV Sub-TLVs Registry  . . . . . .   8
     5.3.  OSPFv3 Extended-LSA Sub-TLVs Registry . . . . . . . . . .   9
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   "Bit Index Explicit Replication Traffic Engineering" (BIER-TE)
   [RFC9262] describes per-packet stateless strict and loose path
   steered replication and forwarding for "Bit Index Explicit
   Replication" (BIER, [RFC8279]) packets.  It is called BIER Tree
   Engineering (BIER-TE) and is intended to be used as the path steering
   mechanism for Traffic Engineering with BIER.  RBS
   [I-D.eckert-bier-rbs] introduces a compact data-structure
   representation of multicast trees called "Recursive Bitstring
   Structure" (RBS) and its use for (stateless) forwarding of packets
   that include this structure in their header.





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   BIER-TE and RBS both use a "bit positions" (BP) for the
   representation of link or adjacency.  [I-D.ietf-bier-te-isis],
   [I-D.ietf-bier-te-ospf], and [I-D.ietf-bier-te-ospfv3] describe IS-
   IS, OSPF, OSPFv3 extensions respectively for distributing
   BitPositions configured on the links in BIER-TE domain.

   As described in section 2.4 in [RFC9262] and section 5 in
   [I-D.eckert-bier-rbs], BIER-TE/RBS inherits the encapsulation
   supporting from BIER unchanged.  The encapsulation defined in
   [RFC8296], which specifies a common header format for both MPLS and
   non-MPLS networks, though the first 20-bits (referred to as BIFT-id)
   of the header is an "MPLS Label" in case of MPLS networks and is a
   local 20-bit opaque value in case of non-MPLS networks.

   As described in section 4.3 of [RFC9262] and section 5 in
   [I-D.eckert-bier-rbs], it is necessary to distinguish the BIER and
   BIER-TE/RBS packet and forwarding. like [RFC8401], [RFC8444],
   [I-D.ietf-bier-ospfv3-extensions], and
   [I-D.ietf-bier-lsr-non-mpls-extensions], the MPLS and non-MPLS
   encapsulation needs to be advertised for BIER-TE/RBS packet
   encapsulation.

   The advertisement can follow the existed BIER-TE BP advertisement,
   but it does not work well if there are many BIER-TE links need to be
   advertised.  Too many octets in the advertisement will be consumed
   even if the same BIFT-id is used for different links.

   This document describes the IS-IS and OSPF protocol extensions that
   are required for BIER-TE/RBS with MPLS and non-MPLS encapsulation
   associated with prefix distributing.

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 [RFC2119].

2.  Terminology

   This document does not introduce more terminologies than [RFC8279],
   [RFC8296], [RFC8401], [RFC9262], [I-D.ietf-bier-te-isis],
   [I-D.ietf-bier-te-ospf], [I-D.ietf-bier-te-ospfv3] and
   [I-D.eckert-bier-rbs].








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3.  Flooding of the BIER-TE/RBS Encapsulation Information in IS-IS

   The BIER-TE MPLS Encapsulation Sub-sub-TLV and BIER-TE non-MPLS
   Encapsulation Sub-sub-TLV are advertised with BIER-Info Sub-TLV,
   which is defined in section 6.1 in [RFC8401].

   As described in section 4.3 in [RFC9262] and section 5 in
   [I-D.eckert-bier-rbs], the label for MPLS encapsulation or the BIFT-
   ID for non-MPLS encapsulation is allocatd per SD:BSL.

   The flooding scope is the same with section 5 in [RFC8401].

3.1.  BIER-TE MPLS Encapsulation Sub-sub-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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |     Type      |     Length    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | subdomain-id  | BS Len|              label                    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                               Figure 1

   Type: TBD (To be assigned by IANA).

   Length: 1-octet.

   subdomain-id: A 1-octet field encoding the Unique value
   identifying the BIER subdomain.  The values allowed in this field
   are specified in Section 1 of [RFC8279].

   BS Len (BitString Length): A 4-bit field encoding the supported
   BitString length associated with this BFR-prefix.  The values
   allowed in this field are specified in Section 2 of [RFC8296].

   Label: A 20-bit field, first label of the range.  The labels are
   as defined in [RFC8296].

   The BIER-TE MPLS encapsulation Sub-sub-TLV may be advertised many
   times for different subdomain-id or BS Len.

3.2.  BIER-TE Non-MPLS Encapsulation Sub-sub-TLV








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        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    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | subdomain-id  | BS Len|                BIFT-ID                |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                               Figure 2

   Type: TBD (To be assigned by IANA).

   Length: 1-octet.

   subdomain-id: A 1-octet field encoding the Unique value
   identifying the BIER subdomain.  The values allowed in this field
   are specified in Section 1 of [RFC8279].

   BS Len (BitString Length): A 4-bit field encoding the supported
   BitString length associated with this BFR-prefix.  The values
   allowed in this field are specified in Section 2 of [RFC8296].

   BIFT-ID: A 20-bit field, first BIFT-ID of the range.  The BIFT-ID
   is as defined in [RFC8296].

   The BIER-TE non-MPLS encapsulation sub-sub-TLV may be advertised many
   times for different subdomain-id or BS Len.

3.2.1.  BIER-TE IPv6 Encapsulation sub-sub-sub-tlv

   As described in section 4 of [I-D.ietf-bier-bierin6], which describes
   how the existing BIER encapsulation specified in [RFC8296] works in a
   non-MPLS IPv6 network, a node that requires IPv6 encapsulation MUST
   advertise the BIER-TE IPv6 encapsulation sub-sub-sub-TLV, which
   follows the associated Non-MPLS Encapsulation, according to local
   configuration or policy in the BIER domain to request other BFRs to
   always use IPv6 encapsulation.

         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      |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                               Figure 3

   Type: TBD (To be assigned by IANA).




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   Length: 0.

4.  Flooding of the BIER-TE/RBS Encapsulation Information in OSPF

   Same with IS-IS, the BIER-TE MPLS Encapsulation Sub-TLV and BIER-TE
   non-MPLS Encapsulation Sub-TLV are Sub-TLVs of BIER Sub-TLV, which is
   defined in section 2.1 in [RFC8444].

   It is similar for OSPFv3, the BIER-TE MPLS Encapsulation Sub-TLV and
   BIER-TE non-MPLS Encapsulation Sub-TLV are Sub-TLVs of BIER Sub-TLV,
   which is defined in section 2.1 in [I-D.ietf-bier-ospfv3-extensions].

   As described in section 4.3 in [RFC9262] and section 5 in
   [I-D.eckert-bier-rbs], the label for MPLS encapsulation or the BIFT-
   ID for non-MPLS encapsulation is allocatd per SD:BSL.

   The format defined below works for both OSPFv2 and OSPFv3.  The
   flooding scope for OSPFv2 is the same with section 2.3 in [RFC8444].
   The flooding scope for OSPFv3 is the same with section 2.2 in
   [I-D.ietf-bier-ospfv3-extensions].

4.1.  BIER-TE MPLS Encapsulation Sub-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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |             Type              |             Length            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |     Max SI    |                  Label                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | BS Len|                   Reserved                            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                               Figure 4

   Type: TBD (To be assigned by IANA).

   Length: 2-octet.

   Max SI: A 1-octet field encoding the maximum Set Identifier (SI)
   (see Section 1 of [RFC8279]) used in the encapsulation for this
   BIER sub-domain for this BitString length.

   Label:A 3-octet field, where the 20 rightmost bits represent the
   first label in the label range.  The 4 leftmost bits MUST be
   ignored.





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   BS Len (BitString Length): A 4-bit field encoding the supported
   BitString length associated with this BFR-prefix.  The values
   allowed in this field are specified in Section 2 of [RFC8296].

   Reserved: SHOULD be set to 0 on transmission and MUST be ignored
   on reception.

   The BIER-TE MPLS encapsulation Sub-TLV may be advertised many times
   for different subdomain-id or BS Len.

4.2.  BIER-TE Non-MPLS Encapsulation Sub-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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |             Type              |             Length            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |     Max SI    |                BIFT-ID                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | BS Len|                   Reserved                            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                               Figure 5

   Type: TBD (To be assigned by IANA).

   Length: 2-octet.

   Max SI: A 1-octet field encoding the maximum Set Identifier (SI)
   (see Section 1 of [RFC8279]) used in the encapsulation for this
   BIER sub-domain for this BitString length.

   BIFT-ID: A 3-octet field, where the 20 rightmost bits represent
   the first value in the range.  The 4 leftmost bits MUST be
   ignored.

   BS Len (BitString Length): A 4-bit field encoding the supported
   BitString length associated with this BFR-prefix.  The values
   allowed in this field are specified in Section 2 of [RFC8296].

   Reserved: SHOULD be set to 0 on transmission and MUST be ignored
   on reception.

   The BIER-TE non-MPLS encapsulation Sub-TLV may be advertised many
   times for different subdomain-id or BS Len.






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4.2.1.  BIER-TE IPv6 Encapsulation sub-sub-tlv

   As described in section 4 of [I-D.ietf-bier-bierin6], which describes
   how the existing BIER encapsulation specified in [RFC8296] works in a
   non-MPLS IPv6 network, a node that requires IPv6 encapsulation MUST
   advertise the BIER-TE IPv6 encapsulation sub-sub-sub-TLV, which
   follows the associated Non-MPLS Encapsulation, according to local
   configuration or policy in the BIER domain to request other BFRs to
   always use IPv6 encapsulation.

         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      |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                               Figure 6

   Type: TBD (To be assigned by IANA).

   Length: 0.

5.  IANA Considerations

   The document requests new allocations from the IANA registries as
   follows:

5.1.  IS-IS Sub-sub-TLVs for BIER Info sub-TLV Registry

   BIER-TE MPLS Encapsulation Sub-sub-TLV: TBD (suggested value 3)

   BIER-TE non-MPLS Encapsulation Sub-sub-TLV: TBD (suggested value 4)

   IANA is requested to create a registry for "IS-IS BIER-TE non-MPLS
   Encapsulation Sub-sub-TLV".  The type field for the registry consists
   of 1 octet, with possible values from 1 to 255 (the value 0 is
   reserved).  The allocation policy for this field is to be "First Come
   First Serve".  A "BIER-TE IPv6 encapsulation Sub-sub-sub-TLV" type
   (TBD, suggested value 1) is requested to be assigned in it.

5.2.  OSPFv2 Extended Prefix TLV Sub-TLVs Registry

   BIER-TE MPLS Encapsulation Sub-TLV: TBD (suggested value 12)

   BIER-TE non-MPLS Encapsulation Sub-TLV: TBD (suggested value 13)






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   IANA is requested to create a registry for "OSPFv2 BIER-TE non-MPLS
   Encapsulation Sub-TLV".  The type field for the registry consists of
   2 octets, with possible values from 1 to 65535 (the value 0 is
   reserved).  The allocation policy for this field is to be "First Come
   First Serve".  A "BIER-TE IPv6 encapsulation Sub-sub-sub-TLV" type
   (TBD, suggested value 1) is requested to be assigned in it.

5.3.  OSPFv3 Extended-LSA Sub-TLVs Registry

   BIER-TE MPLS Encapsulation Sub-TLV: TBD (suggested value 12)

   BIER-TE non-MPLS Encapsulation Sub-TLV: TBD (suggested value 13)

   IANA is requested to create a registry for "OSPFv3 BIER-TE non-MPLS
   Encapsulation Sub-TLV".  The type field for the registry consists of
   2 octets, with possible values from 1 to 65535 (the value 0 is
   reserved).  The allocation policy for this field is to be "First Come
   First Serve".  A "BIER-TE IPv6 encapsulation Sub-sub-sub-TLV" type
   (TBD, suggested value 1) is requested to be assigned in it.

6.  Security Considerations

   This document does not introduce more security considerations than
   [RFC9262] and [I-D.ietf-bier-te-isis], [I-D.ietf-bier-te-ospf],
   [I-D.ietf-bier-te-ospfv3] and [I-D.eckert-bier-rbs].

7.  References

7.1.  Normative References

   [I-D.ietf-bier-bierin6]
              Zhang, Z., Zhang, Z. J., Wijnands, I., Mishra, M. P.,
              Bidgoli, H., and G. S. Mishra, "Supporting BIER in IPv6
              Networks (BIERin6)", Work in Progress, Internet-Draft,
              draft-ietf-bier-bierin6-07, 27 March 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-bier-
              bierin6-07>.

   [I-D.ietf-bier-lsr-non-mpls-extensions]
              Dhanaraj, S., Yan, G., Wijnands, I., Psenak, P., Zhang, Z.
              J., and J. Xie, "LSR Extensions for BIER non-MPLS
              Encapsulation", Work in Progress, Internet-Draft, draft-
              ietf-bier-lsr-non-mpls-extensions-01, 19 September 2022,
              <https://datatracker.ietf.org/doc/html/draft-ietf-bier-
              lsr-non-mpls-extensions-01>.






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   [I-D.ietf-bier-ospfv3-extensions]
              Psenak, P., Nainar, N. K., and I. Wijnands, "OSPFv3
              Extensions for BIER", Work in Progress, Internet-Draft,
              draft-ietf-bier-ospfv3-extensions-07, 1 December 2022,
              <https://datatracker.ietf.org/doc/html/draft-ietf-bier-
              ospfv3-extensions-07>.

   [I-D.ietf-bier-te-isis]
              Chen, H., McBride, M., Wang, A., Mishra, G. S., Fan, Y.,
              Liu, L., and X. Liu, "IS-IS Extensions for BIER-TE", Work
              in Progress, Internet-Draft, draft-ietf-bier-te-isis-08, 6
              July 2023, <https://datatracker.ietf.org/doc/html/draft-
              ietf-bier-te-isis-08>.

   [I-D.ietf-bier-te-ospf]
              Chen, H., McBride, M., Wang, A., Mishra, G. S., Fan, Y.,
              Liu, L., and X. Liu, "OSPFv2 Extensions for BIER-TE", Work
              in Progress, Internet-Draft, draft-ietf-bier-te-ospf-06, 5
              July 2023, <https://datatracker.ietf.org/doc/html/draft-
              ietf-bier-te-ospf-06>.

   [I-D.ietf-bier-te-ospfv3]
              Chen, H., McBride, M., Wang, A., Mishra, G. S., Fan, Y.,
              Liu, L., and X. Liu, "OSPFv3 Extensions for BIER-TE", Work
              in Progress, Internet-Draft, draft-ietf-bier-te-ospfv3-06,
              5 July 2023, <https://datatracker.ietf.org/doc/html/draft-
              ietf-bier-te-ospfv3-06>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC8279]  Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
              Przygienda, T., and S. Aldrin, "Multicast Using Bit Index
              Explicit Replication (BIER)", RFC 8279,
              DOI 10.17487/RFC8279, November 2017,
              <https://www.rfc-editor.org/info/rfc8279>.

   [RFC8296]  Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
              Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation
              for Bit Index Explicit Replication (BIER) in MPLS and Non-
              MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January
              2018, <https://www.rfc-editor.org/info/rfc8296>.







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   [RFC8401]  Ginsberg, L., Ed., Przygienda, T., Aldrin, S., and Z.
              Zhang, "Bit Index Explicit Replication (BIER) Support via
              IS-IS", RFC 8401, DOI 10.17487/RFC8401, June 2018,
              <https://www.rfc-editor.org/info/rfc8401>.

   [RFC8444]  Psenak, P., Ed., Kumar, N., Wijnands, IJ., Dolganow, A.,
              Przygienda, T., Zhang, J., and S. Aldrin, "OSPFv2
              Extensions for Bit Index Explicit Replication (BIER)",
              RFC 8444, DOI 10.17487/RFC8444, November 2018,
              <https://www.rfc-editor.org/info/rfc8444>.

   [RFC9262]  Eckert, T., Ed., Menth, M., and G. Cauchie, "Tree
              Engineering for Bit Index Explicit Replication (BIER-TE)",
              RFC 9262, DOI 10.17487/RFC9262, October 2022,
              <https://www.rfc-editor.org/info/rfc9262>.

7.2.  Informative References

   [I-D.eckert-bier-rbs]
              Eckert, T. T., Menth, M., Geng, X., Zheng, X., Meng, R.,
              and F. Li, "Recursive BitString Structure (RBS) Addresses
              for BIER and MSR6", Work in Progress, Internet-Draft,
              draft-eckert-bier-rbs-00, 24 October 2022,
              <https://datatracker.ietf.org/doc/html/draft-eckert-bier-
              rbs-00>.

Authors' Addresses

   Zheng Zhang
   ZTE Corporation
   China
   Email: zhang.zheng@zte.com.cn


   Yuehua Wei
   ZTE Corporation
   China
   Email: wei.yuehua@zte.com.cn


   Benchong Xu
   ZTE Corporation
   China
   Email: xu.benchong@zte.com.cn


   IJsbrand Wijnands
   Arrcus



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   Email: ice@braindump.be


















































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