| < draft-chen-bier-frr-04.txt | draft-chen-bier-frr-05.txt > | |||
|---|---|---|---|---|
| Network Working Group H. Chen, Ed. | Network Working Group H. Chen, Ed. | |||
| Internet-Draft M. McBride | Internet-Draft M. McBride | |||
| Intended status: Informational Futurewei | Intended status: Informational Futurewei | |||
| Expires: July 6, 2022 S. Lindner | Expires: October 5, 2022 S. Lindner | |||
| M. Menth | M. Menth | |||
| University of Tuebingen | University of Tuebingen | |||
| A. Wang | A. Wang | |||
| China Telecom | China Telecom | |||
| G. Mishra | G. Mishra | |||
| Verizon Inc. | Verizon Inc. | |||
| Y. Liu | Y. Liu | |||
| China Mobile | China Mobile | |||
| Y. Fan | Y. Fan | |||
| Casa Systems | Casa Systems | |||
| L. Liu | L. Liu | |||
| Fujitsu | Fujitsu | |||
| X. Liu | X. Liu | |||
| Volta Networks | Volta Networks | |||
| January 2, 2022 | April 3, 2022 | |||
| BIER Fast ReRoute | BIER Fast ReRoute | |||
| draft-chen-bier-frr-04 | draft-chen-bier-frr-05 | |||
| Abstract | Abstract | |||
| BIER is a scalable multicast overlay [RFC8279] that utilizes a | BIER is a scalable multicast overlay [RFC8279] that utilizes a | |||
| routing underlay, e.g., IP, to build up its Bit Index Forwarding | routing underlay, e.g., IP, to build up its Bit Index Forwarding | |||
| Tables (BIFTs). This document proposes Fast Reroute Extensions for | Tables (BIFTs). This document proposes Fast Reroute for BIER (BIER- | |||
| BIER (BIER-FRR). It protects BIER traffic after detecting the | FRR). It protects BIER traffic after detecting the failure of a link | |||
| failure of a link or node in the core of a BIER domain until affected | or node in the core of a BIER domain until affected BIFT entries are | |||
| BIFT entries are recomputed after reconvergence of the routing | recomputed after reconvergence of the routing underlay. BIER-FRR is | |||
| underlay. The BIER-FRR extensions are applied locally at the point | applied locally at the point of local repair (PLR) and does not | |||
| of local repair (PLR) and do not introduce any per-flow state. The | introduce any per-flow state. The document specifies nomenclature | |||
| document specifies nomenclature for BIER-FRR and gives examples for | for BIER-FRR and gives examples for its integration in BIER | |||
| its integration in BIER forwarding. Furthermore, it presents | forwarding. Furthermore, it presents operation modes for BIER-FRR. | |||
| operation modes for BIER-FRR. Link and node protection may be chosen | Link and node protection may be chosen as protection level. | |||
| as protection level. Moreover, the backup strategies tunnel-based | Moreover, the backup strategies tunnel-based BIER-FRR and LFA-based | |||
| BIER-FRR and LFA-based BIER-FRR are defined and compared. | BIER-FRR are defined and compared. | |||
| Requirements Language | Requirements Language | |||
| The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", | The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", | |||
| "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this | "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this | |||
| document are to be interpreted as described in [RFC2119] [RFC8174] | document are to be interpreted as described in [RFC2119] [RFC8174] | |||
| when, and only when, they appear in all capitals, as shown here. | when, and only when, they appear in all capitals, as shown here. | |||
| Status of This Memo | Status of This Memo | |||
| skipping to change at page 2, line 20 ¶ | skipping to change at page 2, line 20 ¶ | |||
| Internet-Drafts are working documents of the Internet Engineering | Internet-Drafts are working documents of the Internet Engineering | |||
| Task Force (IETF). Note that other groups may also distribute | Task Force (IETF). Note that other groups may also distribute | |||
| working documents as Internet-Drafts. The list of current Internet- | working documents as Internet-Drafts. The list of current Internet- | |||
| Drafts is at https://datatracker.ietf.org/drafts/current/. | Drafts is at https://datatracker.ietf.org/drafts/current/. | |||
| Internet-Drafts are draft documents valid for a maximum of six months | Internet-Drafts are draft documents valid for a maximum of six months | |||
| and may be updated, replaced, or obsoleted by other documents at any | and may be updated, replaced, or obsoleted by other documents at any | |||
| time. It is inappropriate to use Internet-Drafts as reference | time. It is inappropriate to use Internet-Drafts as reference | |||
| material or to cite them other than as "work in progress." | material or to cite them other than as "work in progress." | |||
| This Internet-Draft will expire on July 6, 2022. | This Internet-Draft will expire on October 5, 2022. | |||
| Copyright Notice | Copyright Notice | |||
| Copyright (c) 2022 IETF Trust and the persons identified as the | Copyright (c) 2022 IETF Trust and the persons identified as the | |||
| document authors. All rights reserved. | document authors. All rights reserved. | |||
| This document is subject to BCP 78 and the IETF Trust's Legal | This document is subject to BCP 78 and the IETF Trust's Legal | |||
| Provisions Relating to IETF Documents | Provisions Relating to IETF Documents | |||
| (https://trustee.ietf.org/license-info) in effect on the date of | (https://trustee.ietf.org/license-info) in effect on the date of | |||
| publication of this document. Please review these documents | publication of this document. Please review these documents | |||
| carefully, as they describe your rights and restrictions with respect | carefully, as they describe your rights and restrictions with respect | |||
| to this document. Code Components extracted from this document must | to this document. Code Components extracted from this document must | |||
| include Simplified BSD License text as described in Section 4.e of | include Simplified BSD License text as described in Section 4.e of | |||
| the Trust Legal Provisions and are provided without warranty as | the Trust Legal Provisions and are provided without warranty as | |||
| described in the Simplified BSD License. | described in the Simplified BSD License. | |||
| Table of Contents | Table of Contents | |||
| 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 | 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 | |||
| 2. Extensions for BIER-FRR . . . . . . . . . . . . . . . . . . . 5 | 2. Definition of BIER-FRR . . . . . . . . . . . . . . . . . . . 5 | |||
| 2.1. Definition of Forwarding Actions . . . . . . . . . . . . 5 | 2.1. Definition of Forwarding Actions . . . . . . . . . . . . 5 | |||
| 2.2. Definition of Backup Forwarding Entries . . . . . . . . . 5 | 2.2. Definition of Backup Forwarding Entries . . . . . . . . . 5 | |||
| 2.3. Activating and Deactivating Backup Forwarding Entries . . 6 | 2.3. Activating and Deactivating Backup Forwarding Entries . . 6 | |||
| 2.4. Computation of the Backup F-BM . . . . . . . . . . . . . 7 | 2.4. Computation of the Backup F-BM . . . . . . . . . . . . . 7 | |||
| 3. Representations for BIER-FRR Forwarding Data . . . . . . . . 7 | 3. Representations for BIER-FRR Forwarding Data . . . . . . . . 7 | |||
| 3.1. Potential Emergence of Redundant Packets . . . . . . . . 7 | 3.1. Potential Emergence of Redundant Packets . . . . . . . . 7 | |||
| 3.2. Primary BIFT and Single Backup BIFT . . . . . . . . . . . 9 | 3.2. Primary BIFT and Single Backup BIFT . . . . . . . . . . . 9 | |||
| 3.3. Primary BIFT and Failure-Specific Backup BIFTs . . . . . 10 | 3.3. Primary BIFT and Failure-Specific Backup BIFTs . . . . . 10 | |||
| 4. Protection Levels . . . . . . . . . . . . . . . . . . . . . . 11 | 4. Protection Levels . . . . . . . . . . . . . . . . . . . . . . 11 | |||
| 4.1. Link Protection . . . . . . . . . . . . . . . . . . . . . 11 | 4.1. Link Protection . . . . . . . . . . . . . . . . . . . . . 11 | |||
| skipping to change at page 4, line 15 ¶ | skipping to change at page 4, line 15 ¶ | |||
| would be dropped. BIER traffic can be delivered again only after | would be dropped. BIER traffic can be delivered again only after | |||
| reconvergence of the routing underlay and recalculation of the BIFT. | reconvergence of the routing underlay and recalculation of the BIFT. | |||
| Thus, tunneling BIER packets can help to reach the BFR-NBR in case of | Thus, tunneling BIER packets can help to reach the BFR-NBR in case of | |||
| a link failure by leveraging FRR capabilities of the routing underlay | a link failure by leveraging FRR capabilities of the routing underlay | |||
| if such mechanisms are available. However, this does not help in | if such mechanisms are available. However, this does not help in | |||
| case of a node failure. Then, all destinations having the failed | case of a node failure. Then, all destinations having the failed | |||
| node as BFR-NBR cannot be reached anymore. As BIER carries multicast | node as BFR-NBR cannot be reached anymore. As BIER carries multicast | |||
| traffic which has often realtime requirements, there is a particular | traffic which has often realtime requirements, there is a particular | |||
| need to protect BIER traffic against too long outages after failures. | need to protect BIER traffic against too long outages after failures. | |||
| In this document we propose nomenclature for Fast Reroute Extensions | In this document we propose nomenclature for Fast Reroute in BIER | |||
| for BIER (BIER-FRR). As soon as a BFR detects a BFR-NBR is | (BIER-FRR). As soon as a BFR detects a BFR-NBR is unreachable, BIER- | |||
| unreachable, BIER-FRR enables a BFR to quickly reroute affected BIER | FRR enables a BFR to quickly reroute affected BIER packets with the | |||
| packets with the help of backup forwarding entries. To avoid | help of backup forwarding entries. To avoid redundant packets, | |||
| redundant packets, backup forwarding entries should be processed | backup forwarding entries should be processed prior to normal | |||
| prior to normal forwarding entries. To achieve that goal, two | forwarding entries. To achieve that goal, two possible | |||
| possible representations for backup forwarding entries are proposed. | representations for backup forwarding entries are proposed. | |||
| The protection level can be either link protection or node | The protection level can be either link protection or node | |||
| protection. Link protection protects only the failure of a link. It | protection. Link protection protects only the failure of a link. It | |||
| is simple but may not work if a BFR fails. Node protection is more | is simple but may not work if a BFR fails. Node protection is more | |||
| complex but also protects against the failure of BFRs. The backup | complex but also protects against the failure of BFRs. The backup | |||
| strategy determines the selection of the backup forwarding entries. | strategy determines the selection of the backup forwarding entries. | |||
| Examples for backup strategies are tunnel-based BIER-FRR and LFA- | Examples for backup strategies are tunnel-based BIER-FRR and LFA- | |||
| based BIER-FRR | based BIER-FRR | |||
| skipping to change at page 5, line 7 ¶ | skipping to change at page 5, line 7 ¶ | |||
| topology-independent BIER-LFAs leverage explicit paths to reach | topology-independent BIER-LFAs leverage explicit paths to reach | |||
| the backup BFR-NBR. In contrast to tunnel-based FRR, LFA-based | the backup BFR-NBR. In contrast to tunnel-based FRR, LFA-based | |||
| BIER-FRR does not require fast reroute mechanisms in the routing | BIER-FRR does not require fast reroute mechanisms in the routing | |||
| underlay. | underlay. | |||
| BIER-FRR as presented in this document follows a primary/backup path | BIER-FRR as presented in this document follows a primary/backup path | |||
| principle, also known as 1:1 protection. It is opposite to 1+1 | principle, also known as 1:1 protection. It is opposite to 1+1 | |||
| protection which denotes a live-live protection principle. This has | protection which denotes a live-live protection principle. This has | |||
| been considered for BIER in [BrAl17]. | been considered for BIER in [BrAl17]. | |||
| 2. Extensions for BIER-FRR | 2. Definition of BIER-FRR | |||
| In this section, forwarding actions and backup forwarding entries are | In this section, forwarding actions and backup forwarding entries are | |||
| defined. Then, the computation of the backup F-BM and the BIER | defined. Then, the BIER forwarding process with BIER-FRR and the | |||
| forwarding process with BIER-FRR are explained. | computation of the backup F-BM are explained. | |||
| 2.1. Definition of Forwarding Actions | 2.1. Definition of Forwarding Actions | |||
| A BFR-NBR is directly connected if it is a next hop on the network | A BFR-NBR is directly connected if it is a next hop on the network | |||
| layer, i.e., if it can be reached via the link layer technology. | layer, i.e., if it can be reached via the link layer technology. | |||
| Otherwise, the BFR-NBR is indirectly connected. | Otherwise, the BFR-NBR is indirectly connected. | |||
| We define the following forwarding actions. | We define the following forwarding actions. | |||
| o Plain: Sends the mere BIER packet to a BFR-NBR via a direct link | o Plain: Sends the mere BIER packet to a BFR-NBR via a direct link | |||
| skipping to change at page 26, line 21 ¶ | skipping to change at page 26, line 21 ¶ | |||
| [I-D.chen-bier-egress-protect] | [I-D.chen-bier-egress-protect] | |||
| Chen, H., McBride, M., Wang, A., Mishra, G. S., Liu, Y., | Chen, H., McBride, M., Wang, A., Mishra, G. S., Liu, Y., | |||
| Menth, M., Khasanov, B., Geng, X., Fan, Y., Liu, L., and | Menth, M., Khasanov, B., Geng, X., Fan, Y., Liu, L., and | |||
| X. Liu, "BIER Egress Protection", draft-chen-bier-egress- | X. Liu, "BIER Egress Protection", draft-chen-bier-egress- | |||
| protect-03 (work in progress), October 2021. | protect-03 (work in progress), October 2021. | |||
| [I-D.ietf-rtgwg-segment-routing-ti-lfa] | [I-D.ietf-rtgwg-segment-routing-ti-lfa] | |||
| Litkowski, S., Bashandy, A., Filsfils, C., Francois, P., | Litkowski, S., Bashandy, A., Filsfils, C., Francois, P., | |||
| Decraene, B., and D. Voyer, "Topology Independent Fast | Decraene, B., and D. Voyer, "Topology Independent Fast | |||
| Reroute using Segment Routing", draft-ietf-rtgwg-segment- | Reroute using Segment Routing", draft-ietf-rtgwg-segment- | |||
| routing-ti-lfa-07 (work in progress), June 2021. | routing-ti-lfa-08 (work in progress), January 2022. | |||
| [MeLi20b] Merling, D., Lindner, S., and M. Menth, "P4-Based | [MeLi20b] Merling, D., Lindner, S., and M. Menth, "P4-Based | |||
| Implementation of BIER and BIER-FRR for Scalable and | Implementation of BIER and BIER-FRR for Scalable and | |||
| Resilient Multicast", November 2020. | Resilient Multicast", November 2020. | |||
| [MeLi21] Merling, D., Lindner, S., and M. Menth, "Hardware-based | [MeLi21] Merling, D., Lindner, S., and M. Menth, "Hardware-based | |||
| Evaluation of Scalable and Resilient Multicast with BIER | Evaluation of Scalable and Resilient Multicast with BIER | |||
| in P4", March 2020. | in P4", March 2020. | |||
| [RFC4090] Pan, P., Ed., Swallow, G., Ed., and A. Atlas, Ed., "Fast | [RFC4090] Pan, P., Ed., Swallow, G., Ed., and A. Atlas, Ed., "Fast | |||
| End of changes. 10 change blocks. | ||||
| 27 lines changed or deleted | 27 lines changed or added | |||
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