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Versions: 00                                                            
Network Working Group                                            H. Chen
Internet-Draft                                                M. McBride
Intended status: Standards Track                               Futurewei
Expires: January 12, 2022                                      G. Mishra
                                                            Verizon Inc.
                                                                  Y. Liu
                                                            China Mobile
                                                                 A. Wang
                                                           China Telecom
                                                                  L. Liu
                                                                 Fujitsu
                                                                  X. Liu
                                                          Volta Networks
                                                           July 11, 2021


                   PCE for BIER-TE Ingress Protection
               draft-chen-pce-bier-te-ingress-protect-00

Abstract

   This document describes extensions to Path Computation Element (PCE)
   communication Protocol (PCEP) for protecting the ingress of a BIER-TE
   path.

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 RFC 2119 [RFC2119].

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 https://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 12, 2022.




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Copyright Notice

   Copyright (c) 2021 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
   (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 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.  Terminologies . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  BIER-TE Path Ingress Protection Example . . . . . . . . . . .   3
   4.  Behavior around Ingress Failure . . . . . . . . . . . . . . .   4
     4.1.  Source Detect . . . . . . . . . . . . . . . . . . . . . .   5
     4.2.  Backup Ingress Detect . . . . . . . . . . . . . . . . . .   5
     4.3.  Both Detect . . . . . . . . . . . . . . . . . . . . . . .   5
   5.  Extensions to PCEP  . . . . . . . . . . . . . . . . . . . . .   5
     5.1.  Capability for Ingress Protection . . . . . . . . . . . .   6
       5.1.1.  Capability for Ingress Protection with Backup Ingress   6
       5.1.2.  Capability for Ingress Protection with Traffic Source   7
     5.2.  BIER-TE Path Ingress Protection . . . . . . . . . . . . .   8
       5.2.1.  Extensions for Backup Ingress . . . . . . . . . . . .   8
       5.2.2.  Extensions for Traffic Source . . . . . . . . . . . .  11
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  14
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  14
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  14
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   The fast protection of a transit node of a "Bit Index Explicit
   Replication" (BIER) Traffic Engineering (BIER-TE) path or tunnel is
   described in [I-D.chen-bier-te-frr].  [RFC8424] presents extensions
   to RSVP-TE for the fast protection of the ingress node of a traffic
   engineering (TE) Label Switching Path (LSP).  However, these
   documents do not discuss any protocol extensions for the fast
   protection of the ingress node of a BIER-TE path or tunnel.



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   This document fills that gap and specifies protocol extensions to
   Path Computation Element (PCE) communication Protocol (PCEP) for the
   fast protection of the ingress node of a BIER-TE path or tunnel.
   Ingress node and ingress, fast protection and protection as well as
   BIER-TE path and BIER-TE tunnel will be used exchangeably in the
   following sections.

2.  Terminologies

   The following terminologies are used in this document.

   PCE:  Path Computation Element

   PCEP:  PCE communication Protocol

   PCC:  Path Computation Client

   BIER:  Bit Index Explicit Replication

   CE:  Customer Edge

   PE:  Provider Edge

   TE:  Traffic Engineering

3.  BIER-TE Path Ingress Protection Example

   Figure 1 shows an example of protecting ingress PE1 of a BIER-TE
   path, which is from ingress PE1 to egress nodes PE3 and PE4.  This
   primary BIER-TE path is represented by *** in the figure.  The
   ingress of the primary BIER-TE path is called primary ingress.

                *******  *******
            [PE1]-----[P1]-----[PE3]        PE1 Primary Ingress
            / |       #|*\#####  |          PEx Provider Edge
           /  |       #| *\__    |          CEx Customer Edge
      [CE1]   |       #|  ***\   |          Px  Non Provider Edge
           \  |       #|     *\  |          *** Primary BIER-TE Path
            \ |       #|      *\ |          ### Backup BIER-TE Path
            [PE2]-----[P2]-----[PE4]        PE2 Backup Ingress
                 #####    #####

             Figure 1: Protecting Ingress PE1 of BIER-TE Path

   The backup BIER-TE path is from ingress PE2 to egress nodes PE3 and
   PE4, which is represented by ### in the figure.  The ingress of the
   backup BIER-TE path is called backup ingress.




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   In normal operations, CE1 sends the packets with a multicast group
   and source to ingress PE1, which imports/encapsulates the packets
   into the BIER-TE path through adding a BIER-TE header.  The header
   contains the BIER-TE path from ingress PE1 to egress nodes PE3 and
   PE4.

   When CE1 detects the failure of ingress PE1 using a failure detection
   mechanism such as BFD, it switches the traffic to backup ingress PE2,
   which imports the traffic from CE1 into the backup BIER-TE path.
   When the traffic is imported into the backup path, it is sent to the
   egress nodes PE3 and PE4 along the path.

   Given the traffic source (e.g., CE1), ingress (e.g., PE1) and
   egresses (e.g., PE3 and PE4) of the primary BIER-TE path, the PCE
   computes a backup ingress (e.g., PE2), a backup BIER-TE path from the
   backup ingress to the egresses, and sends the backup BIER-TE path to
   the PCC of the backup ingress.  It also sends the backup ingress,
   primary ingress and the traffic description to the PCC of the traffic
   source (e.g., CE1).

   When the PCC of the traffic source receives the backup ingress,
   primary ingress and traffic description, it sets up the fast
   detection of the primary ingress failure and the switch over target
   backup ingress.  This setup lets the traffic source node switch the
   traffic (to be sent to the primary ingress) to the backup ingress
   when it detects the failure of the primary ingress.

   When the PCC of the backup ingress receives the backup BIER-TE path,
   it adds a forwarding entry into its BIFT.  This entry encapsulates
   the packets from the traffic source in the backup BIER-TE path.  This
   makes the backup ingress send the traffic received from the traffic
   source to the egress nodes via the backup BIER-TE path.

4.  Behavior around Ingress Failure

   This section describes the behavior of some nodes connected to the
   ingress before and after the ingress fails.  These nodes are the
   traffic source (e.g., CE1) and the backup ingress (e.g., PE2).  It
   presents three ways in which these nodes work together to protect the
   ingress.  The first way is called source detect, where the traffic
   source is responsible for fast detecting the failure of the ingress.
   The second way is called backup ingress detect, in which the backup
   ingress is responsible for fast detecting the failure of the ingress.
   The third way is called both detect, where both the traffic source
   and the backup ingress are responsible for fast detecting the failure
   of the ingress.





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4.1.  Source Detect

   In normal operations, i.e., before the failure of the ingress, the
   traffic source sends the traffic to the ingress of the primary BIER-
   TE path.  The backup ingress (e.g., PE2) is ready to import the
   traffic from the traffic source into the backup BIER-TE path
   installed.

   When the traffic source detects the failure of the ingress, it
   switches the traffic to the backup ingress, which delivers the
   traffic to the egress nodes of the BIER-TE path via the backup BIER-
   TE path.

4.2.  Backup Ingress Detect

   The traffic source (e.g., CE1) always sends the traffic to both the
   ingress (e.g., PE1) of the primary BIER-TE path and the backup
   ingress (e.g., PE2).

   The backup ingress does not import any traffic from the traffic
   source into the backup BIER-TE path in normal operations.  When it
   detects the failure of the ingress of the primary BIER-TE path, it
   imports the traffic from the source into the backup BIER-TE path.

   For the backup ingress to fast detect the failure of the primary
   ingress, it SHOULD directly connect to the primary ingress.  When a
   PCE computes a backup ingress and a backup BIER-TE path, it SHOULD
   consider this.

4.3.  Both Detect

   In normal operations, i.e., before the failure of the ingress, the
   traffic source sends the traffic to the ingress of the primary BIER-
   TE path.  When it detects the failure of the ingress, it switches the
   traffic to the backup ingress.

   The backup ingress does not import any traffic from the traffic
   source into the backup BIER-TE path in normal operations.  When it
   detects the failure of the ingress of the primary BIER-TE path, it
   imports the traffic from the source into the backup BIER-TE path.

5.  Extensions to PCEP

   A PCC runs on each of the edge nodes such as PEs and CEs of a network
   normally.  A PCE runs on a server as a controller to communicate with
   PCCs.  The PCE and the PCCs running on backup ingress PEs and traffic
   source CEs work together to support protection for the ingress of a
   BIER-TE path.



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5.1.  Capability for Ingress Protection

5.1.1.  Capability for Ingress Protection with Backup Ingress

   When a PCE and a PCC running on a backup ingress establish a PCEP
   session between them, they exchange their capabilities of supporting
   protection for the ingress node of a BIER-TE path/tunnel.

   A new sub-TLV called BIER-TE_INGRESS_PROTECTION_CAPABILITY is
   defined.  It is included in the PATH_SETUP_TYPE_CAPABILITY TLV with
   PST = TBD1 (suggested value 2 for protecting the ingress of a BIER-TE
   path/tunnel) in the OPEN object, which is exchanged in Open messages
   when a PCC and a PCE establish a PCEP session between them.  Its
   format is illustrated below.

     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 = TBD2          |           Length=4            |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |           Reserved            |        Flags              |D|A|
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

          Figure 2: BIER-TE_INGRESS_PROTECTION_CAPABILITY sub-TLV

   Type:  TBD2 is to be assigned by IANA.

   Length:  4.

   Reserved:  2 octets.  Must be set to zero in transmission and ignored
      on reception.

   Flags:  2 octets.  Two flag bits are defined.

      o  D flag bit: A PCC sets this flag to 1 to indicate that it is
         able to detect its adjacent node's failure quickly.

      o  A flag bit: A PCE sets this flag to 1 to request a PCC to let
         the forwarding entry for the backup BIER-TE path/tunnel be
         Active.

   A PCC, which supports ingress protection for a BIER-TE tunnel/path,
   sends a PCE an Open message containing BIER-
   TE_INGRESS_PROTECTION_CAPABILITY sub-TLV.  This sub-TLV indicates
   that the PCC is capable of supporting the ingress protection for a
   BIER-TE tunnel/path.





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   A PCE, which supports ingress protection for a BIER-TE tunnel/path,
   sends a PCC an Open message containing BIER-
   TE_INGRESS_PROTECTION_CAPABILITY sub-TLV.  This sub-TLV indicates
   that the PCE is capable of supporting the ingress protection for a
   BIER-TE tunnel/path.

   If both a PCC and a PCE support BIER-
   TE_INGRESS_PROTECTION_CAPABILITY, each of the Open messages sent by
   the PCC and PCE contains PATH-SETUP-TYPE-CAPABILITY TLV with a PST
   list containing PST=TBD1 and a BIER-TE-INGRESS_PROTECTION_CAPABILITY
   sub-TLV.

   If a PCE receives an Open message without a BIER-
   TE_INGRESS_PROTECTION_CAPABILITY sub-TLV from a PCC, then the PCE
   MUST not send the PCC any request for ingress protection of a BIER-TE
   path/tunnel.

   If a PCC receives an Open message without a BIER-
   TE_INGRESS_PROTECTION_CAPABILITY sub-TLV from a PCE, then the PCC
   MUST ignore any request for ingress protection of a BIER-TE path/
   tunnel from the PCE.

   If a PCC sets D flag to zero, then the PCE SHOULD send the PCC an
   Open message with A flag set to one and the fast detection of the
   failure of the primary ingress MUST be done by the traffic source.
   When the PCE sends the PCC a message for initiating a backup BIER-TE
   path, the PCC MUST let the forwarding entry for the backup BIER-TE
   path be Active.

5.1.2.  Capability for Ingress Protection with Traffic Source

   When a PCE and a PCC running on a traffic source node establish a
   PCEP session between them, they exchange their capabilities of
   supporting protection for the ingress node of a BIER-TE path/tunnel.

   The PCECC-CAPABILITY sub-TLV defined in
   [I-D.ietf-pce-pcep-extension-for-pce-controller] is included in the
   OPEN object in the PATH-SETUP-TYPE-CAPABILITY TLV, which is exchanged
   in Open messages when a PCC and a PCE establish a PCEP session
   between them.

   A new flag bit P is defined in the Flags field of the PCECC-
   CAPABILITY sub-TLV:

   o  P flag (for Ingress Protection): if set to 1 by a PCEP speaker,
      the P flag indicates that the PCEP speaker supports and is willing
      to handle the PCECC based central controller instructions for
      ingress protection.  The bit MUST be set to 1 by both a PCC and a



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      PCE for the PCECC ingress protection instruction download/report
      on a PCEP session.

5.2.  BIER-TE Path Ingress Protection

   This section specifies the extensions to PCEP for the backup ingress
   and the traffic source.  The extensions let the traffic source

     S1:  fast detect the failure of the primary ingress and switch the
      traffic to the backup ingress when the traffic source detects the
      failure of the primary ingress, or

     S2:  always send the traffic to both the primary ingress and the
      backup ingress.

   The extensions let the backup ingress

     B1:  always import the traffic received from the traffic source
      with possible service ID into the backup BIER-TE path, or

     B2:  import the traffic with possible service ID into the backup
      BIER-TE path when the backup ingress detects the failure of the
      primary ingress.

   The following lists the combinations of Si and Bi (i = 1,2) for
   different ways of failure detects.

     Source Detect:  S1 and B1.

     Backup Ingress Detect:  S2 and B2.

     Both Detect:  S1 and B2.

5.2.1.  Extensions for Backup Ingress

   For the packets from the traffic source, if the primary ingress
   (i.e., the ingress of the primary BIER-TE path) encapsulates the
   packets with a service ID or label into the BIER-TE path, the backup
   ingress MUST have this service ID or label and encapsulates the
   packets with the service ID or label into the backup BIER-TE path
   when the primary ingress fails.

   If the backup ingress is requested to detect the failure of the
   primary ingress, it MUST have the information about the primary
   ingress such as the address of the primary ingress.

   A new TLV called BIER-TE_INGRESS_PROTECTION TLV is defined to
   transfer the information about the primary ingress and/or the service



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   ID or label.  When a PCE sends the PCC of a backup ingress a
   PCInitiate message for initiating a backup BIER-TE path/tunnel to
   protect the primary ingress of a primary BIER-TE path/tunnel, the
   message contains this TLV in the RP/SRP object.  Its format is
   illustrated below.

     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 = TBD3           |        Length (variable)      |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |           Reserved            |        Flags                |A|
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ~                                                               ~
    ~                        sub-TLVs (optional)                    ~
    ~                                                               ~
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Figure 3: BIER-TE_INGRESS_PROTECTION TLV

   Type:  TBD3 is to be assigned by IANA.

   Length:  Variable.

   Reserved:  2 octets.  Must be set to zero in transmission and ignored
      on reception.

   Flags:  2 octets.  One flag bit is defined.

         A flag bit: it is set to 1 or 0 by PCE.

         o  1 is to request the backup ingress to let the forwarding
            entry for the backup BIER-TE path/tunnel be Active always.
            In this case, the traffic source detects the failure of the
            primary ingress and switches the traffic to the backup
            ingress when it detects the failure.

         o  0 is to request the backup ingress to detect the failure of
            the primary ingress and let the forwarding entry for the
            backup BIER-TE path/tunnel be Active when the primary
            ingress fails.  In this case, the TLV includes the primary
            ingress address in a Primary-Ingress sub-TLV.  The traffic
            source can send the traffic to both the primary ingress and
            the backup ingress.  It may switch the traffic to the backup
            ingress from the primary ingress when it detects the failure
            of the primary ingress.





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   Two optional sub-TLVs are defined.  One is Service sub-TLV.  The
   other is Primary-Ingress sub-TLV.  The Multicast Flow Specification
   TLV for IPv4 or IPv6, which is defined in
   [I-D.ietf-pce-pcep-flowspec], is used as a sub-TLV to indicate the
   traffic to be imported into the backup BIER-TE path.

5.2.1.1.  Service sub-TLV

   A Service sub-TLV contains a service label such as VPN service label
   or ID to be added into a packet to be carried by a BIER-TE path/
   tunnel.  It has two formats: one for the service identified by a
   label and the other for the service identified by a service
   identifier (ID) of 32 or 128 bits, which are illustrated below.

     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 = TBD4           |          Length (4)           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |        zero           |       Service Label (20 bits)         |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                      Figure 4: Service Label sub-TLV

   Type:  TBD4 is to be assigned by IANA.

   Length:  4.

   Service Label:  the least significant 20 bits.  It represents a label
      of 20 bits.

     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 = TBD5           |         Length (4/16)         |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                        Service ID (4 or 16 octets)            |
    ~                                                               ~
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                       Figure 5: Service ID sub-TLV

   Type:  TBD5 is to be assigned by IANA.

   Length:  4 or 16.

   Service ID:  4 or 16 octets.  It represents Identifier (ID) of a
      service in 4 or 16 octets.



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5.2.1.2.  Primary-Ingress sub-TLV

   A Primary-Ingress sub-TLV indicates the IP address of the primary
   ingress node of a primary BIER-TE path/tunnel.  It has two formats:
   one for primary ingress node IPv4 address and the other for primary
   ingress node IPv6 address, which are illustrated below.

     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 = TBD6           |          Length (4)           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |            Primary Ingress IPv4 Address (4 octets)            |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

              Figure 6: Primary Ingress IPv4 Address sub-TLV

   Type:  TBD6 is to be assigned by IANA.

   Length:  4.

   Primary Ingress IPv4 Address:  4 octets.  It represents an IPv4 host
      address of the primary ingress node of a BIER-TE path/tunnel.

     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 = TBD7           |         Length (16)           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |            Primary Ingress IPv6 Address (16 octets)           |
    ~                                                               ~
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

              Figure 7: Primary Ingress IPv6 Address sub-TLV

   Type:  TBD7 is to be assigned by IANA.

   Length:  16.

   Primary Ingress IPv6 Address:  16 octets.  It represents an IPv6 host
      address of the primary ingress node of a BIER-TE path/tunnel.

5.2.2.  Extensions for Traffic Source

   If the traffic source is requested to detect the failure of the
   primary ingress and switch the traffic (to be sent to the primary
   ingress) to the backup ingress when the primary ingress fails, it
   MUST have the information about the backup ingress, the primary



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   ingress and the traffic.  This information may be transferred via a
   CCI object for BIER-TE-INGRESS-PROTECTION to the PCC of the traffic
   source node from a PCE.

   If the traffic source PCC does not accept the request from the PCE or
   support the extensions, the PCE SHOULD have the information about the
   behavior of the traffic source configured such as whether it detects
   the failure of the primary ingress.  Based on the information, the
   PCE instructs the backup ingress accordingly.

   The Central Control Instructions (CCI) Object is defined in
   [I-D.ietf-pce-pcep-extension-for-pce-controller] for a PCE as a
   controller to send instructions for LSPs to a PCC.  This document
   defines a new object-type (TBDt) for BIER-TE ingress protection based
   on the CCI object.  The body of the object with the new object-type
   is illustrated below.  The object may be in PCRpt, PCUpd, or
   PCInitiate message.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            CC-ID                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          Reserved             |             Flags         |B|D|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                        Optional TLV                         //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

             Figure 8: BIER-TE-INGRESS-PROTECTION Object Body

   CC-ID:  It is the same as described in
      [I-D.ietf-pce-pcep-extension-for-pce-controller].

   Flags:  Two flag bits D and B are defined as follows:

      D: D = 1 instructs the PCC of the traffic source to Detect the
         failure of the primary ingress and switch the traffic to the
         backup ingress when it detects the failure.

      B: B = 1 instructs the PCC of the traffic source to send the
         traffic to Both the primary ingress and the backup ingress.

   Optional TLV:  Primary ingress TLV, backup ingress TLV and/or
      Multicast Flow Specification TLV.





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   The primary ingress sub-TLV defined above is used as a TLV to contain
   the information about the primary ingress in the object.  The
   Multicast Flow Specification TLV for IPv4 or IPv6, which is defined
   in [I-D.ietf-pce-pcep-flowspec], is used to contain the information
   about the traffic in the object.  A new TLV, called backup ingress
   TLV, is defined to contain the information about the backup ingress
   in the object.

5.2.2.1.  Backup-Ingress TLV

   A Backup-Ingress TLV indicates the IP address of the ingress node of
   a backup BIER-TE path/tunnel.  It has two formats: one for backup
   ingress node IPv4 address and the other for backup ingress node IPv6
   address, which are illustrated below.  They have the same format as
   the Primary-Ingress sub-TLVs.

     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 = TBD8           |          Length (4)           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |             Backup Ingress IPv4 Address (4 octets)            |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Figure 9: Backup Ingress IPv4 Address TLV

   Type:  TBD8 is to be assigned by IANA.

   Length:  4.

   Backup Ingress IPv4 Address:  4 octets.  It represents an IPv4 host
      address of the backup ingress.

     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 = TBD9           |         Length (16)           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |             Backup Ingress IPv6 Address (16 octets)           |
    ~                                                               ~
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 10: Backup Ingress IPv6 Address TLV

   Type:  TBD9 is to be assigned by IANA.

   Length:  16.




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   Backup Ingress IPv6 Address:  16 octets.  It represents an IPv6 host
      address of the backup ingress node.

6.  IANA Considerations

   TBD

7.  Security Considerations

   TBD

8.  Acknowledgements

   TBD

9.  References

9.1.  Normative References

   [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>.

   [RFC5440]  Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
              Element (PCE) Communication Protocol (PCEP)", RFC 5440,
              DOI 10.17487/RFC5440, March 2009,
              <https://www.rfc-editor.org/info/rfc5440>.

   [RFC8231]  Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
              Computation Element Communication Protocol (PCEP)
              Extensions for Stateful PCE", RFC 8231,
              DOI 10.17487/RFC8231, September 2017,
              <https://www.rfc-editor.org/info/rfc8231>.

9.2.  Informative References

   [I-D.chen-bier-te-frr]
              Chen, H., McBride, M., Liu, Y., Wang, A., Mishra, G. S.,
              Fan, Y., Liu, L., and X. Liu, "BIER-TE Fast ReRoute",
              draft-chen-bier-te-frr-00 (work in progress), February
              2021.









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   [I-D.ietf-pce-pcep-extension-for-pce-controller]
              Li, Z., Peng, S., Negi, M. S., Zhao, Q., and C. Zhou,
              "PCEP Procedures and Protocol Extensions for Using PCE as
              a Central Controller (PCECC) of LSPs", draft-ietf-pce-
              pcep-extension-for-pce-controller-14 (work in progress),
              March 2021.

   [I-D.ietf-pce-pcep-flowspec]
              Dhody, D., Farrel, A., and Z. Li, "PCEP Extension for Flow
              Specification", draft-ietf-pce-pcep-flowspec-12 (work in
              progress), October 2020.

   [RFC8402]  Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
              Decraene, B., Litkowski, S., and R. Shakir, "Segment
              Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
              July 2018, <https://www.rfc-editor.org/info/rfc8402>.

   [RFC8424]  Chen, H., Ed. and R. Torvi, Ed., "Extensions to RSVP-TE
              for Label Switched Path (LSP) Ingress Fast Reroute (FRR)
              Protection", RFC 8424, DOI 10.17487/RFC8424, August 2018,
              <https://www.rfc-editor.org/info/rfc8424>.

Authors' Addresses

   Huaimo Chen
   Futurewei
   Boston, MA
   USA

   Email: Huaimo.chen@futurewei.com


   Mike McBride
   Futurewei

   Email: michael.mcbride@futurewei.com


   Gyan S. Mishra
   Verizon Inc.
   13101 Columbia Pike
   Silver Spring  MD 20904
   USA

   Phone:  301 502-1347
   Email: gyan.s.mishra@verizon.com





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   Yisong Liu
   China Mobile

   Email: liuyisong@chinamobile.com


   Aijun Wang
   China Telecom
   Beiqijia Town, Changping District
   Beijing,    102209
   China

   Email: wangaj3@chinatelecom.cn


   Lei Liu
   Fujitsu


   USA

   Email: liulei.kddi@gmail.com


   Xufeng Liu
   Volta Networks

   McLean, VA
   USA

   Email: xufeng.liu.ietf@gmail.com




















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