rfc9604.original   rfc9604.txt 
PCE Working Group S. Sivabalan Internet Engineering Task Force (IETF) S. Sivabalan
Internet-Draft Ciena Corporation Request for Comments: 9604 Ciena Corporation
Intended status: Standards Track C. Filsfils Category: Standards Track C. Filsfils
Expires: 21 September 2022 Cisco Systems, Inc. ISSN: 2070-1721 Cisco Systems, Inc.
J. Tantsura J. Tantsura
Microsoft Corporation Nvidia
S. Previdi S. Previdi
C. Li, Ed. C. Li, Ed.
Huawei Technologies Huawei Technologies
20 March 2022 August 2024
Carrying Binding Label/Segment Identifier (SID) in PCE-based Networks. Carrying Binding Label/SID in PCE-Based Networks
draft-ietf-pce-binding-label-sid-15
Abstract Abstract
In order to provide greater scalability, network confidentiality, and In order to provide greater scalability, network confidentiality, and
service independence, Segment Routing (SR) utilizes a Binding Segment service independence, Segment Routing (SR) utilizes a Binding Segment
Identifier (SID) (called BSID) as described in RFC 8402. It is Identifier (BSID), as described in RFC 8402. It is possible to
possible to associate a BSID to an RSVP-TE-signaled Traffic associate a BSID to an RSVP-TE-signaled Traffic Engineering (TE)
Engineering Label Switched Path or an SR Traffic Engineering path. Label Switched Path (LSP) or an SR TE path. The BSID can be used by
The BSID can be used by an upstream node for steering traffic into an upstream node for steering traffic into the appropriate TE path to
the appropriate TE path to enforce SR policies. This document enforce SR policies. This document specifies the concept of binding
specifies the concept of binding value, which can be either an MPLS value, which can be either an MPLS label or a Segment Identifier
label or Segment Identifier. It further specifies an extension to (SID). It further specifies an extension to Path Computation Element
Path Computation Element (PCE) communication Protocol(PCEP) for Communication Protocol (PCEP) for reporting the binding value by a
reporting the binding value by a Path Computation Client (PCC) to the Path Computation Client (PCC) to the Path Computation Element (PCE)
PCE to support PCE-based Traffic Engineering policies. to support PCE-based TE policies.
Status of This Memo Status of This Memo
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provisions of BCP 78 and BCP 79.
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and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9604.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction
1.1. Motivation and Example . . . . . . . . . . . . . . . . . 4 1.1. Motivation and Example
1.2. Summary of the Extension . . . . . . . . . . . . . . . . 5 1.2. Summary of the Extension
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 5 2. Requirements Language
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Terminology
4. Path Binding TLV . . . . . . . . . . . . . . . . . . . . . . 6 4. Path Binding TLV
4.1. SRv6 Endpoint Behavior and SID Structure . . . . . . . . 8 4.1. SRv6 Endpoint Behavior and SID Structure
5. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 10 5. Operation
6. Binding SID in SR-ERO . . . . . . . . . . . . . . . . . . . . 12 6. Binding SID in SR-ERO
7. Binding SID in SRv6-ERO . . . . . . . . . . . . . . . . . . . 12 7. Binding SID in SRv6-ERO
8. PCE Allocation of Binding label/SID . . . . . . . . . . . . . 12 8. PCE Allocation of Binding Label/SID
9. Implementation Status . . . . . . . . . . . . . . . . . . . . 14 9. Security Considerations
9.1. Huawei . . . . . . . . . . . . . . . . . . . . . . . . . 15 10. Manageability Considerations
9.2. Cisco . . . . . . . . . . . . . . . . . . . . . . . . . . 15 10.1. Control of Function and Policy
10. Security Considerations . . . . . . . . . . . . . . . . . . . 16 10.2. Information and Data Models
11. Manageability Considerations . . . . . . . . . . . . . . . . 16 10.3. Liveness Detection and Monitoring
11.1. Control of Function and Policy . . . . . . . . . . . . . 17 10.4. Verify Correct Operations
11.2. Information and Data Models . . . . . . . . . . . . . . 17 10.5. Requirements on Other Protocols
11.3. Liveness Detection and Monitoring . . . . . . . . . . . 17 10.6. Impact on Network Operations
11.4. Verify Correct Operations . . . . . . . . . . . . . . . 17 11. IANA Considerations
11.5. Requirements On Other Protocols . . . . . . . . . . . . 17 11.1. PCEP TLV Type Indicators
11.6. Impact On Network Operations . . . . . . . . . . . . . . 17 11.1.1. TE-PATH-BINDING TLV
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 11.2. LSP Object
12.1. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . 17 11.3. PCEP Error Type and Value
12.1.1. TE-PATH-BINDING TLV . . . . . . . . . . . . . . . . 18 12. References
12.2. LSP Object . . . . . . . . . . . . . . . . . . . . . . . 19 12.1. Normative References
12.3. PCEP Error Type and Value . . . . . . . . . . . . . . . 19 12.2. Informative References
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 20 Acknowledgements
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 20 Contributors
14.1. Normative References . . . . . . . . . . . . . . . . . . 20 Authors' Addresses
14.2. Informative References . . . . . . . . . . . . . . . . . 22
Appendix A. Contributor Addresses . . . . . . . . . . . . . . . 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24
1. Introduction 1. Introduction
A Path Computation Element (PCE) can compute Traffic Engineering A Path Computation Element (PCE) can compute Traffic Engineering (TE)
paths (TE paths) through a network where those paths are subject to paths through a network where those paths are subject to various
various constraints. Currently, TE paths are set up using either the constraints. Currently, TE paths are set up using either the RSVP-TE
RSVP-TE signaling protocol or Segment Routing (SR). We refer to such signaling protocol or Segment Routing (SR). We refer to such paths
paths as RSVP-TE paths and SR-TE paths respectively in this document. as "RSVP-TE paths" and "SR-TE paths", respectively, in this document.
As per [RFC8402] SR allows a head-end node to steer a packet flow As per [RFC8402], SR allows a head-end node to steer a packet flow
along a given path via a Segment Routing Policy (SR Policy). As per along a given path via an SR Policy. As per [RFC9256], an SR Policy
[I-D.ietf-spring-segment-routing-policy], an SR Policy is a framework is a framework that enables the instantiation of an ordered list of
that enables the instantiation of an ordered list of segments on a segments on a node for implementing a source routing policy with a
node for implementing a source routing policy with a specific intent specific intent for traffic steering from that node.
for traffic steering from that node.
As described in [RFC8402], a Binding Segment Identifier (BSID) is As described in [RFC8402], a Binding SID (BSID) is bound to an SR
bound to a Segment Routing (SR) Policy, instantiation of which may Policy, instantiation of which may involve a list of Segment
involve a list of Segment Identifiers (SIDs). Any packets received Identifiers (SIDs). Any packets received with an active segment
with an active segment equal to a BSID are steered onto the bound SR equal to a BSID are steered onto the bound SR Policy. A BSID may be
Policy. A BSID may be either a local (SR Local Block (SRLB)) or a either a local (SR Local Block (SRLB)) or a global (SR Global Block
global (SR Global Block (SRGB)) SID. As per Section 6.4 of (SRGB)) SID. As per Section 6.4 of [RFC9256], a BSID can also be
[I-D.ietf-spring-segment-routing-policy] a BSID can also be
associated with any type of interface or tunnel to enable the use of associated with any type of interface or tunnel to enable the use of
a non-SR interface or tunnel as a segment in a SID list. In this a non-SR interface or tunnel as a segment in a SID list. In this
document, the term 'binding label/SID' is used to generalize the document, the term "binding label/SID" is used to generalize the
allocation of binding value for both SR and non-SR paths. allocation of a binding value for both SR and non-SR paths.
[RFC5440] describes the PCEP for communication between a Path [RFC5440] describes the PCEP for communication between a Path
Computation Client (PCC) and a PCE or between a pair of PCEs as per Computation Client (PCC) and a PCE or between a pair of PCEs as per
[RFC4655]. [RFC8231] specifies extensions to PCEP that allow a PCC [RFC4655]. [RFC8231] specifies extensions to PCEP that allow a PCC
to delegate its Label Switched Paths (LSPs) to a stateful PCE. A to delegate its Label Switched Paths (LSPs) to a stateful PCE. A
stateful PCE can then update the state of LSPs delegated to it. stateful PCE can then update the state of LSPs delegated to it.
[RFC8281] specifies a mechanism allowing a PCE to dynamically [RFC8281] specifies a mechanism allowing a PCE to dynamically
instantiate an LSP on a PCC by sending the path and characteristics. instantiate an LSP on a PCC by sending the path and characteristics.
This document specifies an extension to PCEP to manage the binding of This document specifies an extension to PCEP to manage the binding of
label/SID that can be applied to SR, RSVP-TE, and other path setup label/SID that can be applied to SR, RSVP-TE, and other path setup
types. types.
[RFC8664] provides a mechanism for a PCE (acting as a network [RFC8664] provides a mechanism for a PCE (acting as a network
controller) to instantiate SR-TE paths (candidate paths) for an SR controller) to instantiate SR-TE paths (candidate paths) for an SR
Policy onto a head-end node (acting as a PCC) using PCEP. For more Policy onto a head-end node (acting as a PCC) using PCEP. For more
information on the SR Policy Architecture, see information on the SR Policy Architecture, see [RFC9256].
[I-D.ietf-spring-segment-routing-policy].
1.1. Motivation and Example 1.1. Motivation and Example
A binding label/SID has local significance to the ingress node of the A binding label/SID has local significance to the ingress node of the
corresponding TE path. When a stateful PCE is deployed for setting corresponding TE path. When a stateful PCE is deployed for setting
up TE paths, a binding label/SID reported from the PCC to the up TE paths, a binding label/SID reported from the PCC to the
stateful PCE is useful for the purpose of enforcing end-to-end TE/SR stateful PCE is useful for enforcing an end-to-end TE/SR policy. A
policy. A sample Data Center (DC) and IP/MPLS WAN use-case is sample Data Center (DC) and IP/MPLS WAN use case is illustrated in
illustrated in Figure 1 with a multi-domain PCE. In the IP/MPLS WAN, Figure 1 with a multi-domain PCE. In the IP/MPLS WAN, an SR-TE LSP
an SR-TE LSP is set up using the PCE. The list of SIDs of the SR-TE is set up using the PCE. The list of SIDs of the SR-TE LSP is {A, B,
LSP is {A, B, C, D}. The gateway node 1 (which is the PCC) allocates C, D}. The gateway Node-1 (which is the PCC) allocates a binding SID
a binding SID X and reports it to the PCE. In the MPLS DC network, X and reports it to the PCE. In the MPLS DC network, an end-to-end
an end-to-end SR-TE LSP is established. In order for the access node SR-TE LSP is established. In order for the access node to steer the
to steer the traffic towards Node-1 and over the SR-TE path in WAN, traffic towards Node-1 and over the SR-TE path in WAN, the PCE passes
the PCE passes the SID stack {Y, X} where Y is the node SID of the the SID stack {Y, X} where Y is the node SID of the gateway Node-1 to
gateway node-1 to the access node and X is the BSID. In the absence the access node and X is the BSID. In the absence of the BSID X, the
of the BSID X, the PCE would need to pass the SID stack {Y, A, B, C, PCE would need to pass the SID stack {Y, A, B, C, D} to the access
D} to the access node. This example also illustrates the additional node. This example also illustrates the additional benefit of using
benefit of using the binding label/SID to reduce the number of SIDs the binding label/SID to reduce the number of SIDs imposed by the
imposed by the access nodes with a limited forwarding capacity. access nodes with a limited forwarding capacity.
SID stack SID stack
{Y, X} +--------------+ {Y, X} +--------------+
| Multi-domain | | Multi-domain |
_ _ _ _ _ _ _ _ _ _ _ _ _ _| PCE | _ _ _ _ _ _ _ _ _ _ _ _ _ _| PCE |
| +--------------+ | +--------------+
| ^ | ^
| | Binding | | Binding
| .-----. | SID (X) .-----. | .-----. | SID (X) .-----.
| ( ) | ( ) | ( ) | ( )
skipping to change at page 4, line 45 skipping to change at line 173
+------+ ( ) +-------+ ( ) +-------+ +------+ ( ) +-------+ ( ) +-------+
|Access|_( MPLS DC Network )_|Gateway|_( IP/MPLS WAN )_|Gateway| |Access|_( MPLS DC Network )_|Gateway|_( IP/MPLS WAN )_|Gateway|
| Node | ( ==============> ) |Node-1 | ( ================> ) |Node-2 | | Node | ( ==============> ) |Node-1 | ( ================> ) |Node-2 |
+------+ ( SR-TE path ) +-------+ ( SR-TE path ) +-------+ +------+ ( SR-TE path ) +-------+ ( SR-TE path ) +-------+
'--( )--' Node '--( )--' '--( )--' Node '--( )--'
( ) SID of ( ) ( ) SID of ( )
'-----' Node-1 '-----' '-----' Node-1 '-----'
is Y SIDs for SR-TE LSP: is Y SIDs for SR-TE LSP:
{A, B, C, D} {A, B, C, D}
Figure 1: A Sample Use-case of Binding SID Figure 1: A Sample Use Case of Binding SID
Using the extension defined in this document, a PCC could report to Using the extension defined in this document, a PCC could report to
the stateful PCE the binding label/SID it allocated via a Path the stateful PCE the binding label/SID it allocated via a Path
Computation LSP State Report (PCRpt) message. It is also possible Computation LSP State Report (PCRpt) message. It is also possible
for a stateful PCE to request a PCC to allocate a specific binding for a stateful PCE to request a PCC to allocate a specific binding
label/SID by sending a Path Computation LSP Update Request (PCUpd) label/SID by sending a Path Computation LSP Update Request (PCUpd)
message. If the PCC can successfully allocate the specified binding message. If the PCC can successfully allocate the specified binding
value, it reports the binding value to the PCE. Otherwise, the PCC value, it reports the binding value to the PCE. Otherwise, the PCC
sends an error message to the PCE indicating the cause of the sends an error message to the PCE indicating the cause of the
failure. A local policy or configuration at the PCC SHOULD dictate failure. A local policy or configuration at the PCC SHOULD dictate
if the binding label/SID needs to be assigned. if the binding label/SID needs to be assigned.
1.2. Summary of the Extension 1.2. Summary of the Extension
To implement the needed changes to PCEP, in this document, we To implement the needed changes to PCEP, this document introduces a
introduce a new OPTIONAL TLV that a PCC can use in order to report new OPTIONAL TLV that allows a PCC to report the binding label/SID
the binding label/SID associated with a TE LSP, or a PCE to request a associated with a TE LSP or a PCE to request a PCC to allocate any or
PCC to allocate any or a specific binding label/SID value. This TLV a specific binding label/SID value. This TLV is intended for TE LSPs
is intended for TE LSPs established using RSVP-TE, SR-TE, or any established using RSVP-TE, SR-TE, or any other future method. In the
other future method. In the case of SR-TE LSPs, the TLV can carry a case of SR-TE LSPs, the TLV can carry a binding label (for SR-TE
binding label (for SR-TE path with MPLS data-plane) or a binding IPv6 paths with the MPLS data plane) or a binding IPv6 SID (e.g., IPv6
SID (e.g., IPv6 address for SR-TE paths with IPv6 data-plane). address for SR-TE paths with the IPv6 data plane). Throughout this
Throughout this document, the term "binding value" means either an document, the term "binding value" means either an MPLS label or a
MPLS label or a SID. SID.
As another way to use the extension specified in this document, to As another way to use the extension specified in this document, to
support the PCE-based central controller [RFC8283] operation where support the PCE-based central controller [RFC8283] operation where
the PCE would take responsibility for managing some part of the MPLS the PCE would take responsibility for managing some part of the MPLS
label space for each of the routers that it controls, the PCE could label space for each of the routers that it controls, the PCE could
directly make the binding label/SID allocation and inform the PCC. directly make the binding label/SID allocation and inform the PCC.
See Section 8 for details. See Section 8 for details.
In addition to specifying a new TLV, this document specifies how and In addition to specifying a new TLV, this document specifies how and
when a PCC and PCE can use this TLV, how they can allocate a binding when a PCC and PCE can use this TLV, how they can allocate a binding
label/SID, and associated error handling. label/SID, and the associated error handling.
2. Requirements Language 2. 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", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in
14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. Terminology 3. Terminology
The following terminologies are used in this document: The following terminologies are used in this document:
BSID: Binding Segment Identifier. BSID: Binding SID
binding label/SID: a generic term used for the binding segment for binding label/SID: a generic term used for the binding segment for
both SR and non-SR paths. both SR and non-SR paths
binding value: a generic term used for the binding segment as it can binding value: a generic term used for the binding segment as it can
be encoded in various formats (as per the binding type(BT)). be encoded in various formats (as per the Binding Type (BT))
LSP: Label Switched Path. LSP: Label Switched Path
PCC: Path Computation Client. PCC: Path Computation Client
PCEP: Path Computation Element communication Protocol. PCEP: Path Computation Element Communication Protocol
RSVP-TE: Resource ReserVation Protocol-Traffic Engineering. RSVP-TE: Resource Reservation Protocol - Traffic Engineering
SID: Segment Identifier. SID: Segment Identifier
SR: Segment Routing. SR: Segment Routing
4. Path Binding TLV 4. Path Binding TLV
The new optional TLV called "TE-PATH-BINDING TLV" (whose format is The new optional TLV called "TE-PATH-BINDING TLV" (the format is
shown in Figure 2) is defined to carry the binding label/SID for a TE shown in Figure 2) is defined to carry the binding label/SID for a TE
path. This TLV is associated with the LSP object specified in path. This TLV is associated with the LSP object specified in
[RFC8231]. This TLV can also be carried in the PCEP-ERROR object [RFC8231]. This TLV can also be carried in the PCEP-ERROR object
[RFC5440] in case of error. Multiple instances of TE-PATH-BINDING [RFC5440] in case of error. Multiple instances of TE-PATH-BINDING
TLVs MAY be present in the LSP and PCEP-ERROR object. The type of TLVs MAY be present in the LSP and PCEP-ERROR object. The type of
this TLV is 55 (early allocated by IANA). The length is variable. this TLV is 55. The length is variable.
[Note to RFC Editor: Please remove "(early allocated by IANA)" before
publication]
0 1 2 3 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 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 = 55 | Length | | Type = 55 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BT | Flags | Reserved | | BT | Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Binding Value (variable length) ~ ~ Binding Value (variable length) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: TE-PATH-BINDING TLV Figure 2: TE-PATH-BINDING TLV
TE-PATH-BINDING TLV is a generic TLV such that it is able to carry The TE-PATH-BINDING TLV is a generic TLV such that it is able to
binding label/SID (i.e. MPLS label or SRv6 SID). It is formatted carry binding label/SID (i.e., MPLS label or SRv6 SID). It is
according to the rules specified in [RFC5440]. The value portion of formatted according to the rules specified in [RFC5440]. The value
the TLV comprises: portion of the TLV comprises:
Binding Type (BT): A one-octet field that identifies the type of * Binding Type (BT): A one-octet field that identifies the type of
binding included in the TLV. This document specifies the following binding included in the TLV. This document specifies the
BT values: following BT values:
* BT = 0: The binding value is a 20-bit MPLS label value. The TLV - BT = 0: The binding value is a 20-bit MPLS label value. The
is padded to 4-bytes alignment. The Length MUST be set to 7 (the TLV is padded to 4-bytes alignment. The Length MUST be set to
padding is not included in the length, as per [RFC5440] 7 (the padding is not included in the length, as per [RFC5440],
Section 7.1) and the first 20 bits are used to encode the MPLS Section 7.1), and the first 20 bits are used to encode the MPLS
label value. label value.
* BT = 1: The binding value is a 32-bit MPLS label stack entry as - BT = 1: The binding value is a 32-bit MPLS Label Stack Entry as
per [RFC3032] with Label, TC [RFC5462], S, and TTL values encoded. per [RFC3032] with Label, Traffic Class (TC) [RFC5462], S, and
Note that the receiver MAY choose to override TC, S, and TTL TTL values encoded. Note that the receiver MAY choose to
values according to its local policy. The Length MUST be set to override TC, S, and TTL values according to its local policy.
8. The Length MUST be set to 8.
* BT = 2: The binding value is an SRv6 SID with the format of a - BT = 2: The binding value is an SRv6 SID with the format of a
16-octet IPv6 address, representing the binding SID for SRv6. The 16-octet IPv6 address, representing the binding SID for SRv6.
Length MUST be set to 20. The Length MUST be set to 20.
* BT = 3: The binding value is a 24 octet field, defined in - BT = 3: The binding value is a 24-octet field, defined in
Section 4.1, that contains the SRv6 SID as well as its Behavior Section 4.1, that contains the SRv6 SID as well as its Behavior
and Structure. The Length MUST be set to 28. and Structure. The Length MUST be set to 28.
Section 12.1.1 defines the IANA registry used to maintain all these Section 11.1.1 defines the IANA registry used to maintain these
binding types as well as any future ones. Note that multiple TE- binding types as well as any future ones. Note that multiple TE-
PATH-BINDING TLVs with same or different Binding Types MAY be present PATH-BINDING TLVs with the same or different binding types MAY be
for the same LSP. A PCEP speaker could allocate multiple TE-PATH- present for the same LSP. A PCEP speaker could allocate multiple
BINDING TLVs (of the same BT), and use different binding values in TE-PATH-BINDING TLVs (of the same BT) and use different binding
different domains or use-cases based on a local policy. values in different domains or use cases based on a local policy.
Flags: 1 octet of flags. The following flag is defined in the new * Flags: 1 octet of flags. The following flag is defined in the new
registry "TE-PATH-BINDING TLV Flag field" as described in "TE-PATH-BINDING TLV Flag field" registry as described in
Section 12.1.1: Section 11.1.1:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|R| | |R| |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Figure 3: Flags Figure 3: Flags
where: Where:
* R (Removal - 1 bit): When set, the requesting PCEP peer requires - R (Removal - 1 bit): When set, the requesting PCEP peer
the removal of the binding value for the LSP. When unset, the requires the removal of the binding value for the LSP. When
PCEP peer indicates that the binding value is added or retained unset, the PCEP peer indicates that the binding value is added
for the LSP. This flag is used in the PCRpt and PCUpd messages. or retained for the LSP. This flag is used in the PCRpt and
It is ignored in other PCEP messages. PCUpd messages. It is ignored in other PCEP messages.
* The unassigned flags MUST be set to 0 while sending and ignored on - The unassigned flags MUST be set to 0 while sending and ignored
receipt. on receipt.
Reserved: MUST be set to 0 while sending and ignored on receipt. * Reserved: MUST be set to 0 while sending and ignored on receipt.
Binding Value: A variable-length field, padded with trailing zeros to * Binding Value: A variable-length field, padded with trailing zeros
a 4-octet boundary. When the BT is 0, the 20 bits represent the MPLS to a 4-octet boundary. When the BT is 0, the 20 bits represent
label. When the BT is 1, the 32 bits represent the MPLS label stack the MPLS label. When the BT is 1, the 32 bits represent the MPLS
entry as per [RFC3032]. When the BT is 2, the 128 bits represent the label stack entry as per [RFC3032]. When the BT is 2, the 128
SRv6 SID. When the BT is 3, the Binding Value also contains the SRv6 bits represent the SRv6 SID. When the BT is 3, the binding value
Endpoint Behavior and SID Structure, defined in Section 4.1. In this also contains the SRv6 Endpoint Behavior and SID Structure,
document, the TE-PATH-BINDING TLV is considered to be empty if no defined in Section 4.1. In this document, the TE-PATH-BINDING TLV
Binding Value is present. Note that the length of the TLV would be 4 is considered to be empty if no binding value is present. Note
in such a case. that the length of the TLV would be 4 in such a case.
4.1. SRv6 Endpoint Behavior and SID Structure 4.1. SRv6 Endpoint Behavior and SID Structure
This section specifies the format of the Binding Value in the TE- This section specifies the format of the binding value in the TE-
PATH-BINDING TLV when the BT is set to 3 for the SRv6 Binding SIDs PATH-BINDING TLV when the BT is set to 3 for the SRv6 Binding SIDs
[RFC8986]. The format is shown in Figure 4. [RFC8986]. The format is shown in Figure 4.
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| SRv6 Binding SID (16 octets) | | SRv6 Binding SID (16 octets) |
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Endpoint Behavior | | Reserved | Endpoint Behavior |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LB Length | LN Length | Fun. Length | Arg. Length | | LB Length | LN Length | Fun. Length | Arg. Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: SRv6 Endpoint Behavior and SID Structure Figure 4: SRv6 Endpoint Behavior and SID Structure
The Binding Value consists of: The Binding Value consists of:
* SRv6 Binding SID: 16 octets. The 128-bit IPv6 address, * SRv6 Binding SID: 16 octets. The 128-bit IPv6 address,
representing the binding SID for SRv6. representing the binding SID for SRv6.
* Reserved: 2 octets. It MUST be set to 0 on transmit and ignored * Reserved: 2 octets. It MUST be set to 0 on transmit and ignored
on receipt. on receipt.
* Endpoint Behavior: 2 octets. The Endpoint Behavior code point for * Endpoint Behavior: 2 octets. The Endpoint Behavior code point for
this SRv6 SID as per the IANA subregistry called "SRv6 Endpoint this SRv6 SID as defined by the "SRv6 Endpoint Behaviors" registry
Behaviors", created by [RFC8986]. When the field is set with the [RFC8986]. When the field is set with the value 0, the Endpoint
value 0, the endpoint behavior is considered unknown. Behavior is considered unknown.
* [RFC8986] defines an SRv6 SID as consisting of LOC:FUNCT:ARG, * [RFC8986] defines an SRv6 SID as consisting of LOC:FUNCT:ARG,
where a locator (LOC) is encoded in the L most significant bits of where a locator (LOC) is encoded in the L most significant bits of
the SID, followed by F bits of function (FUNCT) and A bits of the SID, followed by F bits of function (FUNCT) and A bits of
arguments (ARG). A locator may be represented as B:N where B is arguments (ARG). A locator may be represented as B:N, where B is
the SRv6 SID locator block (IPv6 prefix allocated for SRv6 SIDs by the SRv6 SID locator block (IPv6 prefix allocated for SRv6 SIDs by
the operator) and N is the identifier of the parent node the operator) and N is the identifier of the parent node
instantiating the SID called locator node. The following fields instantiating the SID, called "locator node". The following
are used to advertise the length of each individual part of the fields are used to advertise the length of each individual part of
SRv6 SID as defined in : the SRv6 SID:
- LB Length: 1 octet. SRv6 SID Locator Block length in bits. - LB Length: 1 octet. SRv6 SID Locator Block length in bits.
- LN Length: 1 octet. SRv6 SID Locator Node length in bits. - LN Length: 1 octet. SRv6 SID Locator Node length in bits.
- Function Length: 1 octet. SRv6 SID Function length in bits. - Function Length: 1 octet. SRv6 SID Function length in bits.
- Argument Length: 1 octet. SRv6 SID Arguments length in bits. - Arguments Length: 1 octet. SRv6 SID Arguments length in bits.
The total of the locator block, locator node, function, and argument The total of the locator block, locator node, function, and arguments
lengths MUST be lower or equal to 128 bits. If this condition is not lengths MUST be less than or equal to 128 bits. If this condition is
met, the corresponding TE-PATH-BINDING TLV is considered invalid. not met, the corresponding TE-PATH-BINDING TLV is considered invalid.
Also, if the Endpoint Behavior is found to be unknown or Also, if the Endpoint Behavior is found to be unknown or
inconsistent, it is considered invalid. A PCErr message with Error- inconsistent, it is considered invalid. A PCErr message with Error-
Type = 10 ("Reception of an invalid object") and Error-Value = 37 Type = 10 ("Reception of an invalid object") and Error-value = 37
("Invalid SRv6 SID Structure") MUST be sent in such cases. ("Invalid SRv6 SID Structure") MUST be sent in such cases.
The SRv6 SID Structure could be used by the PCE for ease of The SRv6 SID Structure could be used by the PCE for ease of
operations and monitoring. For example, this information could be operations and monitoring. For example, this information could be
used for validation of SRv6 SIDs being instantiated in the network used for validation of SRv6 SIDs being instantiated in the network
and checked for conformance to the SRv6 SID allocation scheme chosen and checked for conformance to the SRv6 SID allocation scheme chosen
by the operator as described in Section 3.2 of [RFC8986]. In the by the operator as described in Section 3.2 of [RFC8986]. In the
future, PCE could also be used for verification and the automation future, PCE could also be used for verification and for automatically
for securing the SRv6 domain by provisioning filtering rules at SR securing the SRv6 domain by provisioning filtering rules at SR domain
domain boundaries as described in Section 5 of [RFC8754]. The boundaries as described in Section 5 of [RFC8754]. The details of
details of these potential applications are outside the scope of this these potential applications are outside the scope of this document.
document.
5. Operation 5. Operation
The binding value is usually allocated by the PCC and reported to a The binding value is usually allocated by the PCC and reported to a
PCE via a PCRpt message (see Section 8 where PCE does the PCE via a PCRpt message (see Section 8 where PCE performs the
allocation). If a PCE does not recognize the TE-PATH-BINDING TLV, it allocation). If a PCE does not recognize the TE-PATH-BINDING TLV, it
would ignore the TLV in accordance with [RFC5440]. If a PCE would ignore the TLV in accordance with [RFC5440]. If a PCE
recognizes the TLV but does not support the TLV, it MUST send a PCErr recognizes the TLV but does not support the TLV, it MUST send a PCErr
with Error-Type = 2 (Capability not supported). with Error-Type = 2 ("Capability not supported").
Multiple TE-PATH-BINDING TLVs are allowed to be present in the same Multiple TE-PATH-BINDING TLVs are allowed to be present in the same
LSP object. This signifies the presence of multiple binding SIDs for LSP object. This signifies the presence of multiple binding SIDs for
the given LSP. In the case of multiple TE-PATH-BINDING TLVs, the the given LSP. In the case of multiple TE-PATH-BINDING TLVs, the
existing instances of TE-PATH-BINDING TLVs MAY be included in the LSP existing instances of TE-PATH-BINDING TLVs MAY be included in the LSP
object. In case of an error condition, the whole message is rejected object. In case of an error condition, the whole message is
and the resulting PCErr message MAY include the offending TE-PATH- rejected, and the resulting PCErr message MAY include the offending
BINDING TLV in the PCEP-ERROR object. TE-PATH-BINDING TLV in the PCEP-ERROR object.
If a PCE recognizes an invalid binding value (e.g., label value from If a PCE recognizes an invalid binding value (e.g., label value from
the reserved MPLS label space), it MUST send a PCErr message with the reserved MPLS label space), it MUST send a PCErr message with
Error-Type = 10 ("Reception of an invalid object") and Error Value = Error-Type = 10 ("Reception of an invalid object") and Error-value =
2 ("Bad label value") as specified in [RFC8664]. 2 ("Bad label value") as specified in [RFC8664].
For SRv6 BSIDs, it is RECOMMENDED to always explicitly specify the For SRv6 BSIDs, it is RECOMMENDED to always explicitly specify the
SRv6 Endpoint Behavior and SID Structure in the TE-PATH-BINDING TLV SRv6 Endpoint Behavior and SID Structure in the TE-PATH-BINDING TLV
by setting the BT (Binding Type) to 3. This can enable the sender to by setting BT to 3. This can enable the sender to have control of
have control of the SRv6 Endpoint Behavior and SID Structure. A the SRv6 Endpoint Behavior and SID Structure. A sender MAY choose to
sender MAY choose to set the BT to 2, in which case the receiving set the BT to 2, in which case the receiving implementation chooses
implementation chooses how to interpret the SRv6 Endpoint Behavior how to interpret the SRv6 Endpoint Behavior and SID Structure
and SID Structure according to local policy. according to local policy.
If a PCC wishes to withdraw a previously reported binding value, it If a PCC wishes to withdraw a previously reported binding value, it
MUST send a PCRpt message with the specific TE-PATH-BINDING TLV with MUST send a PCRpt message with the specific TE-PATH-BINDING TLV with
R flag set to 1. If a PCC wishes to modify a previously reported R flag set to 1. If a PCC wishes to modify a previously reported
binding, it MUST withdraw the former binding value (with R flag set binding, it MUST withdraw the former binding value (with R flag set
in the former TE-PATH-BINDING TLV) and include a new TE-PATH-BINDING in the former TE-PATH-BINDING TLV) and include a new TE-PATH-BINDING
TLV containing the new binding value. Note that other instances of TLV containing the new binding value. Note that other instances of
TE-PATH-BINDING TLVs that are unchanged MAY also be included. If the TE-PATH-BINDING TLVs that are unchanged MAY also be included. If the
unchanged instances are not included, they will remain associated unchanged instances are not included, they will remain associated
with the LSP. with the LSP.
If a PCE requires a PCC to allocate a (or several) specific binding If a PCE requires a PCC to allocate one (or several) specific binding
value(s), it may do so by sending a PCUpd or PCInitiate message value(s), it may do so by sending a PCUpd or PCInitiate message
containing a TE-PATH-BINDING TLV(s). If the value(s) can be containing one or more TE-PATH-BINDING TLVs. If the values can be
successfully allocated, the PCC reports the binding value(s) to the successfully allocated, the PCC reports the binding values to the
PCE. If the PCC considers the binding value specified by the PCE PCE. If the PCC considers the binding value specified by the PCE
invalid, it MUST send a PCErr message with Error-Type = TBD2 invalid, it MUST send a PCErr message with Error-Type = 32 ("Binding
("Binding label/SID failure") and Error Value = TBD3 ("Invalid SID"). label/SID failure") and Error-value = 1 ("Invalid SID"). If the
If the binding value is valid, but the PCC is unable to allocate the binding value is valid but the PCC is unable to allocate the binding
binding value, it MUST send a PCErr message with Error-Type = TBD2 value, it MUST send a PCErr message with Error-Type = 32 ("Binding
("Binding label/SID failure") and Error Value = TBD4 ("Unable to label/SID failure") and Error-value = 2 ("Unable to allocate the
allocate the specified binding value"). Note that, in case of an specified binding value"). Note that, in case of an error, the PCC
error, the PCC rejects the PCUpd or PCInitiate message in its rejects the PCUpd or PCInitiate message in its entirety and can
entirety and can include the offending TE-PATH-BINDING TLV in the include the offending TE-PATH-BINDING TLV in the PCEP-ERROR object.
PCEP-ERROR object.
If a PCE wishes to request the withdrawal of a previously reported If a PCE wishes to request the withdrawal of a previously reported
binding value, it MUST send a PCUpd message with the specific TE- binding value, it MUST send a PCUpd message with the specific TE-
PATH-BINDING TLV with R flag set to 1. If a PCE wishes to modify a PATH-BINDING TLV with R flag set to 1. If a PCE wishes to modify a
previously requested binding value, it MUST request the withdrawal of previously requested binding value, it MUST request the withdrawal of
the former binding value (with R flag set in the former TE-PATH- the former binding value (with R flag set in the former TE-PATH-
BINDING TLV) and include a new TE-PATH-BINDING TLV containing the new BINDING TLV) and include a new TE-PATH-BINDING TLV containing the new
binding value. If a PCC receives a PCUpd message with TE-PATH- binding value. If a PCC receives a PCUpd message with TE-PATH-
BINDING TLV where the R flag is set to 1, but either the binding BINDING TLV where the R flag is set to 1, but either the binding
value is missing (empty TE-PATH-BINDING TLV) or the binding value is value is missing (empty TE-PATH-BINDING TLV) or the binding value is
incorrect, it MUST send a PCErr message with Error-Type = TBD2 incorrect, it MUST send a PCErr message with Error-Type = 32
("Binding label/SID failure") and Error Value = TBD6 ("Unable to ("Binding label/SID failure") and Error-value = 4 ("Unable to remove
remove the binding value"). the binding value").
In some cases, a stateful PCE may want to request that the PCC In some cases, a stateful PCE may want to request that the PCC
allocate a binding value of the PCC's own choosing. It instructs the allocate a binding value of the PCC's own choosing. It instructs the
PCC by sending a PCUpd message containing an empty TE-PATH-BINDING PCC by sending a PCUpd message containing an empty TE-PATH-BINDING
TLV, i.e., no binding value is specified (bringing the Length field TLV, i.e., no binding value is specified (bringing the Length field
of the TLV to 4). A PCE can also request a PCC to allocate a binding of the TLV to 4). A PCE can also request that a PCC allocate a
value at the time of initiation by sending a PCInitiate message with binding value at the time of initiation by sending a PCInitiate
an empty TE-PATH-BINDING TLV. Only one such instance of empty TE- message with an empty TE-PATH-BINDING TLV. Only one such instance of
PATH-BINDING TLV, per BT, SHOULD be included in the LSP object and empty TE-PATH-BINDING TLV, per BT, SHOULD be included in the LSP
others ignored on receipt. If the PCC is unable to allocate a new object; others should be ignored on receipt. If the PCC is unable to
binding value as per the specified BT, it MUST send a PCErr message allocate a new binding value as per the specified BT, it MUST send a
with Error-Type = TBD2 ("Binding label/SID failure") and Error-Value PCErr message with Error-Type = 32 ("Binding label/SID failure") and
= TBD5 ("Unable to allocate a new binding label/SID"). Error-value = 3 ("Unable to allocate a new binding label/SID").
As previously noted, if a message contains an invalid TE-PATH-BINDING As previously noted, if a message contains an invalid TE-PATH-BINDING
TLV that leads to an error condition, the whole message is rejected TLV that leads to an error condition, the whole message is rejected
including any other valid instances of TE-PATH-BINDING TLVs, if any. including any other valid instances of TE-PATH-BINDING TLVs, if any.
The resulting error message MAY include the offending TE-PATH-BINDING The resulting error message MAY include the offending TE-PATH-BINDING
TLV in the PCEP-ERROR object. TLV in the PCEP-ERROR object.
If a PCC receives a TE-PATH-BINDING TLV in any message other than If a PCC receives a TE-PATH-BINDING TLV in any message other than
PCUpd or PCInitiate, it MUST close the corresponding PCEP session PCUpd or PCInitiate, it MUST close the corresponding PCEP session
with the reason "Reception of a malformed PCEP message" (according to with the reason "Reception of a malformed PCEP message" (according to
[RFC5440]). Similarly, if a PCE receives a TE-PATH-BINDING TLV in [RFC5440]). Similarly, if a PCE receives a TE-PATH-BINDING TLV in
any message other than a PCRpt or if the TE-PATH-BINDING TLV is any message other than a PCRpt or if the TE-PATH-BINDING TLV is
associated with any object other than an LSP or PCEP-ERROR object, associated with any object other than an LSP or PCEP-ERROR object,
the PCE MUST close the corresponding PCEP session with the reason the PCE MUST close the corresponding PCEP session with the reason
"Reception of a malformed PCEP message" (according to [RFC5440]). "Reception of a malformed PCEP message" (according to [RFC5440]).
If a TE-PATH-BINDING TLV is absent in the PCRpt message and no If a TE-PATH-BINDING TLV is absent in the PCRpt message and no
binding values were reported before, the PCE MUST assume that the binding values were previously reported, the PCE MUST assume that the
corresponding LSP does not have any binding. Similarly, if TE-PATH- corresponding LSP does not have any binding. Similarly, if TE-PATH-
BINDING TLV is absent in the PCUpd message and no binding values were BINDING TLV is absent in the PCUpd message and no binding values were
reported before, the PCC's local policy dictates how the binding previously reported, the PCC's local policy dictates how the binding
allocations are made for a given LSP. allocations are made for a given LSP.
Note that some binding types have similar information but different Note that some binding types have similar information but different
binding value formats. For example, BT=(2 or 3) is used for the SRv6 binding value formats. For example, BT=(2 or 3) is used for the SRv6
SID and BT=(0 or 1) is used for the MPLS Label. In case a PCEP SID, and BT=(0 or 1) is used for the MPLS Label. In case a PCEP
speaker receives multiple TE-PATH-BINDING TLVs with the same SRv6 SID speaker receives multiple TE-PATH-BINDING TLVs with the same SRv6 SID
or MPLS Label but different BT values, it MUST send a PCErr message or MPLS Label but different BT values, it MUST send a PCErr message
with Error-Type = TBD2 ("Binding label/SID failure") and Error-Value with Error-Type = 32 ("Binding label/SID failure") and Error-value =
= TBD7 ("Inconsistent binding types"). 5 ("Inconsistent binding types").
6. Binding SID in SR-ERO 6. Binding SID in SR-ERO
In PCEP messages, LSP route information is carried in the Explicit In PCEP messages, LSP route information is carried in the Explicit
Route Object (ERO), which consists of a sequence of subobjects. Route Object (ERO), which consists of a sequence of subobjects.
[RFC8664] defines the "SR-ERO subobject" capable of carrying a SID as [RFC8664] defines the "SR-ERO subobject" capable of carrying a SID as
well as the identity of the node/adjacency (NAI) represented by the well as the identity of the Node or Adjacency Identifier (NAI)
SID. The NAI Type (NT) field indicates the type and format of the represented by the SID. The NAI Type (NT) field indicates the type
NAI contained in the SR-ERO. In case of binding SID, the NAI MUST and format of the NAI contained in the SR-ERO. In case of binding
NOT be included and NT MUST be set to zero. [RFC8664] Section 5.2.1 SID, the NAI MUST NOT be included and NT MUST be set to zero.
specifies bit settings and error handling in the case when NT=0. Section 5.2.1 of [RFC8664] specifies bit settings and error handling
in the case when NT=0.
7. Binding SID in SRv6-ERO 7. Binding SID in SRv6-ERO
[I-D.ietf-pce-segment-routing-ipv6] defines the "SRv6-ERO subobject" [RFC9603] defines the "SRv6-ERO subobject" for an SRv6 SID.
for an SRv6 SID. Similarly to SR-ERO (Section 6), the NAI MUST NOT Similarly to SR-ERO (Section 6), the NAI MUST NOT be included and the
be included and the NT MUST be set to zero. [RFC8664] Section 5.2.1 NT MUST be set to zero. Section 5.2.1 of [RFC8664] specifies bit
specifies bit settings and error handling in the case when NT=0. settings and error handling in the case when NT=0.
8. PCE Allocation of Binding label/SID 8. PCE Allocation of Binding Label/SID
Section 5 already includes the scenario where a PCE requires a PCC to Section 5 already includes the scenario where a PCE requires a PCC to
allocate a specified binding value by sending a PCUpd or PCInitiate allocate a specified binding value by sending a PCUpd or PCInitiate
message containing a TE-PATH-BINDING TLV. This section specifies an message containing a TE-PATH-BINDING TLV. This section specifies an
OPTIONAL feature for the PCE to allocate the binding label/SID of its OPTIONAL feature for the PCE to allocate the binding label/SID of its
own accord in the case where the PCE also controls the label space of own accord in the case where the PCE also controls the label space of
the PCC and can make the label allocation on its own as described in the PCC and can make the label allocation on its own as described in
[RFC8283]. Note that the act of requesting a specific binding value [RFC8283]. Note that the act of requesting a specific binding value
(Section 5) is different from the act of allocating a binding label/ (Section 5) is different from the act of allocating a binding label/
SID as described in this section. SID as described in this section.
[RFC8283] introduces the architecture for PCE as a central controller [RFC8283] introduces the architecture for PCE as a central controller
as an extension of the architecture described in [RFC4655] and as an extension of the architecture described in [RFC4655] and
assumes the continued use of PCEP as the protocol used between PCE assumes the continued use of PCEP as the protocol used between PCE
and PCC. [RFC9050] specifies the procedures and PCEP extensions for and PCC. [RFC9050] specifies the procedures and PCEP extensions for
using the PCE as the central controller. It assumes that the using the PCE as the central controller. It assumes that the
exclusive label range to be used by a PCE is known and set on both exclusive label range to be used by a PCE is known and set on both
PCEP peers. A future extension could add the capability to advertise PCEP peers. A future extension could add the capability to advertise
this range via a possible PCEP extension as well (see this range via a possible PCEP extension as well (see
[I-D.li-pce-controlled-id-space]). [PCE-ID-SPACE]).
When PCECC operations are supported as per [RFC9050], the binding When PCE as a Central Controller (PCECC) operations are supported as
label/SID MAY also be allocated by the PCE itself. Both peers need per [RFC9050], the binding label/SID MAY also be allocated by the PCE
to exchange the PCECC capability as described in [RFC9050] before the itself. Both peers need to exchange the PCECC capability as
PCE can allocate the binding label/SID on its own. described in [RFC9050] before the PCE can allocate the binding label/
SID on its own.
A new P flag in the LSP object [RFC8231] is introduced to indicate A new P flag in the LSP object [RFC8231] is introduced to indicate
that the allocation needs to be made by the PCE. Note that the P that the allocation needs to be made by the PCE. Note that the P
flag could be used for other types of allocations (such as path flag could be used for other types of allocations (such as path
segments [I-D.ietf-pce-sr-path-segment]) in future. segments [PCEP-SR]) in the future.
* P (PCE-allocation): If the bit is set to 1, it indicates that the P (PCE-allocation): If the bit is set to 1, it indicates that the
PCC requests PCE to make allocations for this LSP. The TE-PATH- PCC requests that the PCE make allocations for this LSP. The TE-
BINDING TLV in the LSP object identifies that the allocation is PATH-BINDING TLV in the LSP object identifies that the allocation
for a binding label/SID. A PCC MUST set this bit to 1 and include is for a binding label/SID. A PCC MUST set this bit to 1 and
a TE-PATH-BINDING TLV in the LSP object if it wishes to request include a TE-PATH-BINDING TLV in the LSP object if it wishes to
for allocation of binding label/SID by the PCE in the PCEP request an allocation for a binding label/SID by the PCE in the
message. A PCE MUST also set this bit to 1 and include a TE-PATH- PCEP message. A PCE MUST also set this bit to 1 and include a TE-
BINDING TLV to indicate that the binding label/SID is allocated by PATH-BINDING TLV to indicate that the binding label/SID is
PCE and encoded in the PCEP message towards the PCC. Further, if allocated by PCE and encoded in the PCEP message towards the PCC.
the binding label/SID is allocated by the PCC, the PCE MUST set Further, if the binding label/SID is allocated by the PCC, the PCE
this bit to 0 and follow the procedure described in Section 5. MUST set this bit to 0 and follow the procedure described in
Section 5.
Note that - Note that:
* A PCE could allocate the binding label/SID of its own accord for a * A PCE could allocate the binding label/SID of its own accord for a
PCE-initiated or delegated LSP, and inform the PCC in the PCE-initiated or PCE-delegated LSP and inform the PCC in the
PCInitiate message or PCUpd message by setting P=1 and including PCInitiate message or PCUpd message by setting P=1 and including
TE-PATH-BINDING TLV in the LSP object. TE-PATH-BINDING TLV in the LSP object.
* To let the PCC allocate the binding label/SID, a PCE MUST set P=0 * To let the PCC allocate the binding label/SID, a PCE MUST set P=0
and include an empty TE-PATH-BINDING TLV ( i.e., no binding value and include an empty TE-PATH-BINDING TLV (i.e., no binding value
is specified) in the LSP object in PCInitiate/PCUpd message. is specified) in the LSP object in the PCInitiate/PCUpd message.
* To request that the PCE allocate the binding label/SID, a PCC MUST * To request that the PCE allocate the binding label/SID, a PCC MUST
set P=1, D=1, and include an empty TE-PATH-BINDING TLV in PCRpt set P=1, D=1, and include an empty TE-PATH-BINDING TLV in the
message. The PCE will attempt to allocate it and respond to the PCRpt message. The PCE will attempt to allocate it and respond to
PCC with PCUpd message including the allocated binding label/SID the PCC with a PCUpd message that includes the allocated binding
in the TE-PATH-BINDING TLV and P=1, D=1 in the LSP object. If the label/SID in the TE-PATH-BINDING TLV and P=1 and D=1 in the LSP
PCE is unable to allocate, it MUST send a PCErr message with object. If the PCE is unable to allocate the binding label/SID,
Error-Type = TBD2 ("Binding label/SID failure") and Error-Value = it MUST send a PCErr message with Error-Type = 32 ("Binding label/
TBD5 ("Unable to allocate a new binding label/SID"). SID failure") and Error-value = 3 ("Unable to allocate a new
binding label/SID").
* If one or both speakers (PCE and PCC) have not indicated support * If one or both speakers (PCE and PCC) have not indicated support
and willingness to use the PCEP extensions for the PCECC as per and willingness to use the PCEP extensions for the PCECC as per
[RFC9050] and a PCEP peer receives P=1 in the LSP object, it MUST: [RFC9050] and a PCEP peer receives P=1 in the LSP object, they
MUST:
- send a PCErr message with Error-Type=19 (Invalid Operation) and - send a PCErr message with Error-Type = 19 ("Invalid Operation")
Error-value=16 (Attempted PCECC operations when PCECC and Error-value = 16 ("Attempted PCECC operations when PCECC
capability was not advertised) and capability was not advertised") and
- terminate the PCEP session. - terminate the PCEP session.
* A legacy PCEP speaker that does not recognize the P flag in the * A legacy PCEP speaker that does not recognize the P flag in the
LSP object would ignore it in accordance with [RFC8231]. LSP object would ignore it in accordance with [RFC8231].
It is assumed that the label range to be used by a PCE is known and It is assumed that the label range to be used by a PCE is known and
set on both PCEP peers. The exact mechanism is out of the scope of set on both PCEP peers. The exact mechanism is out of the scope of
[RFC9050] or this document. Note that the specific BSID could be [RFC9050] and this document. Note that the specific BSID could be
from the PCE-controlled or the PCC-controlled label space. The PCE from the PCE-controlled or the PCC-controlled label space. The PCE
can directly allocate the label from the PCE-controlled label space can directly allocate the label from the PCE-controlled label space
using P=1 as described above, whereas the PCE can request the using P=1 as described above, whereas the PCE can request the
allocation of a specific BSID from the PCC-controlled label space allocation of a specific BSID from the PCC-controlled label space
with P=0 as described in Section 5. with P=0 as described in Section 5.
Note that, the P-Flag in the LSP object SHOULD NOT be set to 1 Note that the P flag in the LSP object SHOULD NOT be set to 1 without
without the presence of TE-PATH-BINDING TLV or any other future TLV the presence of TE-PATH-BINDING TLV or any other future TLV defined
defined for PCE allocation. On receipt of such an LSP object, the for PCE allocation. On receipt of such an LSP object, the P flag is
P-Flag is ignored. The presence of TE-PATH-BINDING TLV with P=1 ignored. The presence of TE-PATH-BINDING TLV with P=1 indicates the
indicates the allocation is for the binding label/SID. In the allocation is for the binding label/SID. In the future, some other
future, some other TLV (such as one defined in TLV (such as one defined in [PCEP-SR]) could also be used alongside
[I-D.ietf-pce-sr-path-segment]) could also be used alongside P=1 to P=1 to indicate allocation of a different attribute. A future
indicate allocation of a different attribute. A future document document should not attempt to assign semantics to P=1 without
should not attempt to assign semantics to P=1 without limiting its limiting the scope to one that both PCEP peers can agree on.
scope that both PCEP peers could agree on.
9. Implementation Status
[Note to the RFC Editor - remove this section before publication, as
well as remove the reference to RFC 7942.]
This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in [RFC7942].
The description of implementations in this section is intended to
assist the IETF in its decision processes in progressing drafts to
RFCs. Please note that the listing of any individual implementation
here does not imply endorsement by the IETF. Furthermore, no effort
has been spent to verify the information presented here that was
supplied by IETF contributors. This is not intended as, and must not
be construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may
exist.
According to [RFC7942], "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature.
It is up to the individual working groups to use this information as
they see fit".
9.1. Huawei
* Organization: Huawei
* Implementation: Huawei's Router and Controller
* Description: An experimental code-point is used and will be
modified to the value allocated in this document.
* Maturity Level: Production
* Coverage: Full
* Contact: c.l@huawei.com
9.2. Cisco
* Organization: Cisco Systems
* Implementation: Head-end and controller.
* Description: An experimental code-point is used and will be
modified to the value allocated in this document.
* Maturity Level: Production
* Coverage: Full
* Contact: mkoldych@cisco.com
10. Security Considerations 9. Security Considerations
The security considerations described in [RFC5440], [RFC8231], The security considerations described in [RFC5440], [RFC8231],
[RFC8281], [RFC8664], and [RFC9050] are applicable to this [RFC8281], [RFC8664], and [RFC9050] are applicable to this
specification. No additional security measure is required. specification. No additional security measure is required.
As described in [RFC8402] and [RFC8664], SR intrinsically involves an As described in [RFC8402] and [RFC8664], SR intrinsically involves an
entity (whether head-end or a central network controller) controlling entity (whether head-end or a central network controller) controlling
and instantiating paths in the network without the involvement of and instantiating paths in the network without the involvement of
(other) nodes along those paths. Binding SIDs are in effect (other) nodes along those paths. Binding SIDs are in effect
shorthand aliases for longer path representations, and the alias shorthand aliases for longer path representations, and the alias
skipping to change at page 16, line 29 skipping to change at line 656
PCE, and rogue actions by either PCC or PCE could result in shifting PCE, and rogue actions by either PCC or PCE could result in shifting
or misdirecting traffic in ways that are hard for other nodes to or misdirecting traffic in ways that are hard for other nodes to
detect. In particular, when a PCE propagates paths of the form {A, detect. In particular, when a PCE propagates paths of the form {A,
B, BSID} to other entities, the BSID values are opaque, and a rogue B, BSID} to other entities, the BSID values are opaque, and a rogue
PCE can substitute a BSID from a different LSP in such paths to move PCE can substitute a BSID from a different LSP in such paths to move
traffic without the recipient of the path knowing the ultimate traffic without the recipient of the path knowing the ultimate
destination. destination.
The case of BT=3 provides additional opportunities for malfeasance, The case of BT=3 provides additional opportunities for malfeasance,
as it purports to convey information about internal SRv6 SID as it purports to convey information about internal SRv6 SID
structure. There is no mechanism defined to validate this internal Structure. There is no mechanism defined to validate this internal
structure information, and mischaracterizing the division of bits structure information, and mischaracterizing the division of bits
into locator block, locator node, function, and argument can result into locator block, locator node, function, and argument can result
in different interpretation of the bits by PCC and PCE. Most in different interpretation of the bits by PCC and PCE. Most
notably, shifting bits into or out of the "argument" is a direct notably, shifting bits into or out of the "argument" is a direct
vector for affecting processing, but other attacks are also possible. vector for affecting processing, but other attacks are also possible.
Thus, as per [RFC8231], it is RECOMMENDED that these PCEP extensions Thus, as per [RFC8231], it is RECOMMENDED that these PCEP extensions
only be activated on authenticated and encrypted sessions across PCEs only be activated on authenticated and encrypted sessions across PCEs
and PCCs belonging to the same administrative authority, using and PCCs belonging to the same administrative authority, using
Transport Layer Security (TLS) [RFC8253], as per the recommendations Transport Layer Security (TLS) [RFC8253], as per the recommendations
and best current practices in BCP195 [RFC7525] (unless explicitly set and best current practices in RFC 9325 [BCP195] (unless explicitly
aside in [RFC8253]). set aside in [RFC8253]).
11. Manageability Considerations 10. Manageability Considerations
All manageability requirements and considerations listed in All manageability requirements and considerations listed in
[RFC5440], [RFC8231], and [RFC8664] apply to PCEP protocol extensions [RFC5440], [RFC8231], and [RFC8664] apply to PCEP protocol extensions
defined in this document. In addition, requirements and defined in this document. In addition, requirements and
considerations listed in this section apply. considerations listed in this section apply.
11.1. Control of Function and Policy 10.1. Control of Function and Policy
A PCC implementation SHOULD allow the operator to configure the A PCC implementation SHOULD allow the operator to configure the
policy the PCC needs to apply when allocating the binding label/SID. policy the PCC needs to apply when allocating the binding label/SID.
If BT is set to 2, the operator needs to have local policy set to If BT is set to 2, the operator needs to have local policy set to
decide the SID structure and the SRv6 Endpoint Behavior of the BSID. decide the SID structure and the SRv6 Endpoint Behavior of the BSID.
11.2. Information and Data Models 10.2. Information and Data Models
The PCEP YANG module [I-D.ietf-pce-pcep-yang] will be extended to The PCEP YANG module [PCEP-YANG] will be extended to include policy
include policy configuration for binding label/SID allocation. configuration for binding label/SID allocation.
11.3. Liveness Detection and Monitoring 10.3. Liveness Detection and Monitoring
The mechanisms defined in this document do not imply any new liveness The mechanisms defined in this document do not imply any new liveness
detection and monitoring requirements in addition to those already detection and monitoring requirements in addition to those already
listed in [RFC5440]. listed in [RFC5440].
11.4. Verify Correct Operations 10.4. Verify Correct Operations
The mechanisms defined in this document do not imply any new The mechanisms defined in this document do not imply any new
operation verification requirements in addition to those already operation verification requirements in addition to those already
listed in [RFC5440], [RFC8231], and [RFC8664]. listed in [RFC5440], [RFC8231], and [RFC8664].
11.5. Requirements On Other Protocols 10.5. Requirements on Other Protocols
The mechanisms defined in this document do not imply any new The mechanisms defined in this document do not imply any new
requirements on other protocols. requirements on other protocols.
11.6. Impact On Network Operations 10.6. Impact on Network Operations
The mechanisms defined in [RFC5440], [RFC8231], and [RFC8664] also The mechanisms defined in [RFC5440], [RFC8231], and [RFC8664] also
apply to the PCEP extensions defined in this document. apply to the PCEP extensions defined in this document.
12. IANA Considerations 11. IANA Considerations
IANA maintains the "Path Computation Element Protocol (PCEP) Numbers" IANA has allocated code points for the protocol elements described in
registry. This document requests IANA actions to allocate code this document in the "Path Computation Element Protocol (PCEP)
points for the protocol elements defined in this document. Numbers" registry group.
12.1. PCEP TLV Type Indicators 11.1. PCEP TLV Type Indicators
This document defines a new PCEP TLV; IANA is requested to confirm This document defines a new PCEP TLV. IANA has allocated the
the following early allocations from the "PCEP TLV Type Indicators" following in the "PCEP TLV Type Indicators" registry within the PCEP
subregistry of the PCEP Numbers registry, as follows: Numbers registry group:
+=======+=================+===============+ +=======+=================+===========+
| Value | Description | Reference | | Value | Description | Reference |
+=======+=================+===============+ +=======+=================+===========+
+-------+-----------------+---------------+ | 55 | TE-PATH-BINDING | RFC 9604 |
| 55 | TE-PATH-BINDING | This document | +-------+-----------------+-----------+
+-------+-----------------+---------------+
Table 1 Table 1
12.1.1. TE-PATH-BINDING TLV 11.1.1. TE-PATH-BINDING TLV
IANA is requested to create a new subregistry "TE-PATH-BINDING TLV BT IANA has created the "TE-PATH-BINDING TLV BT Field" registry to
field" to manage the value of the Binding Type field in the TE-PATH- manage the values of the binding type field in the TE-PATH-BINDING
BINDING TLV. Initial values for the subregistry are given below. TLV. Initial values are shown below. New values are assigned by
New values are assigned by Standards Action [RFC8126]. Standards Action [RFC8126].
+=======+======================================+===============+ +=======+======================================+===========+
| Value | Description | Reference | | Value | Description | Reference |
+=======+======================================+===============+ +=======+======================================+===========+
+-------+--------------------------------------+---------------+ | 0 | MPLS Label | RFC 9604 |
| 0 | MPLS Label | This document | +-------+--------------------------------------+-----------+
+-------+--------------------------------------+---------------+ | 1 | MPLS Label Stack Entry | RFC 9604 |
| 1 | MPLS Label Stack Entry | This document | +-------+--------------------------------------+-----------+
+-------+--------------------------------------+---------------+ | 2 | SRv6 SID | RFC 9604 |
| 2 | SRv6 SID | This document | +-------+--------------------------------------+-----------+
+-------+--------------------------------------+---------------+ | 3 | SRv6 SID with Behavior and Structure | RFC 9604 |
| 3 | SRv6 SID with Behavior and Structure | This document | +-------+--------------------------------------+-----------+
+-------+--------------------------------------+---------------+ | 4-255 | Unassigned | |
| 4-255 | Unassigned | This document | +-------+--------------------------------------+-----------+
+-------+--------------------------------------+---------------+
Table 2 Table 2
IANA is requested to create a new subregistry "TE-PATH-BINDING TLV IANA has created a new "TE-PATH-BINDING TLV Flag Field" registry to
Flag field" to manage the Flag field in the TE-PATH-BINDING TLV. New manage the Flag field in the TE-PATH-BINDING TLV. New values are to
values are to be assigned by Standards Action [RFC8126]. Each bit be assigned by Standards Action [RFC8126]. Each bit should be
should be tracked with the following qualities: tracked with the following qualities:
* Bit number (count from 0 as the most significant bit) * Bit number (count from 0 as the most significant bit)
* Description * Description
* Reference * Reference
+=====+=============+===============+
| Bit | Description | Reference | +=====+=============+===========+
+=====+=============+===============+ | Bit | Description | Reference |
+-----+-------------+---------------+ +=====+=============+===========+
| 0 | R (Removal) | This document | | 0 | R (Removal) | RFC 9604 |
+-----+-------------+---------------+ +-----+-------------+-----------+
| 1-7 | Unassigned | This document | | 1-7 | Unassigned | |
+-----+-------------+---------------+ +-----+-------------+-----------+
Table 3 Table 3
12.2. LSP Object 11.2. LSP Object
IANA is requested to confirm the early allocation for a new code- IANA has allocated a code point in the "LSP Object Flag Field"
point in the "LSP Object Flag Field" sub-registry for the new P flag registry for the new P flag as follows:
as follows:
+=====+================+===============+ +=====+================+===========+
| Bit | Description | Reference | | Bit | Description | Reference |
+=====+================+===============+ +=====+================+===========+
+-----+----------------+---------------+ | 0 | PCE-allocation | RFC 9604 |
| 0 | PCE-allocation | This document | +-----+----------------+-----------+
+-----+----------------+---------------+
Table 4 Table 4
12.3. PCEP Error Type and Value 11.3. PCEP Error Type and Value
This document defines a new Error-type and associated Error-Values
for the PCErr message. IANA is requested to allocate new error-type
and error-values within the "PCEP-ERROR Object Error Types and
Values" subregistry of the PCEP Numbers registry, as follows:
+============+================+========================+===========+
| Error-Type | Meaning | Error-value | Reference |
+============+================+========================+===========+
+------------+----------------+------------------------+-----------+
| TBD2 | Binding label/ | 0: Unassigned | This |
| | SID failure | | document |
+------------+----------------+------------------------+-----------+
| | | TBD3: Invalid SID | This |
| | | | document |
+------------+----------------+------------------------+-----------+
| | | TBD4: Unable to | This |
| | | allocate the specified | document |
| | | binding value | |
+------------+----------------+------------------------+-----------+
| | | TBD5: Unable to | This |
| | | allocate a new binding | document |
| | | label/SID | |
+------------+----------------+------------------------+-----------+
| | | TBD6: Unable to remove | This |
| | | the binding value | document |
+------------+----------------+------------------------+-----------+
| | | TBD7: Inconsistent | This |
| | | binding types | document |
+------------+----------------+------------------------+-----------+
Table 5 This document defines a new Error-Type and associated Error-values
for the PCErr message. IANA has allocated a new Error-Type and
Error-values within the "PCEP-ERROR Object Error Types and Values"
registry of the PCEP Numbers registry group, as follows:
13. Acknowledgements +============+================+===========================+
| Error-Type | Meaning | Error-value |
+============+================+===========================+
| 32 | Binding label/ | 0: Unassigned |
| | SID failure +---------------------------+
| | | 1: Invalid SID |
| | +---------------------------+
| | | 2: Unable to allocate the |
| | | specified binding value |
| | +---------------------------+
| | | 3: Unable to allocate a |
| | | new binding label/SID |
| | +---------------------------+
| | | 4: Unable to remove the |
| | | binding value |
| | +---------------------------+
| | | 5: Inconsistent binding |
| | | types |
+------------+----------------+---------------------------+
We would like to thank Milos Fabian, Mrinmoy Das, Andrew Stone, Tom Table 5
Petch, Aijun Wang, Olivier Dugeon, and Adrian Farrel for their
valuable comments.
Thanks to Julien Meuric for shepherding. Thanks to John Scudder for 12. References
the AD review.
Thanks to Theresa Enghardt for the GENART review. 12.1. Normative References
Thanks to Martin Vigoureux, Benjamin Kaduk, Eric Vyncke, Lars Eggert, [BCP195] Best Current Practice 195,
Murray Kucherawy, and Erik Kline for the IESG reviews. <https://www.rfc-editor.org/info/bcp195>.
At the time of writing, this BCP comprises the following:
14. References Moriarty, K. and S. Farrell, "Deprecating TLS 1.0 and TLS
1.1", BCP 195, RFC 8996, DOI 10.17487/RFC8996, March 2021,
<https://www.rfc-editor.org/info/rfc8996>.
14.1. Normative References Sheffer, Y., Saint-Andre, P., and T. Fossati,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November
2022, <https://www.rfc-editor.org/info/rfc9325>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y., [RFC3032] Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001, Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001,
<https://www.rfc-editor.org/info/rfc3032>. <https://www.rfc-editor.org/info/rfc3032>.
skipping to change at page 21, line 25 skipping to change at line 854
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440, Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009, DOI 10.17487/RFC5440, March 2009,
<https://www.rfc-editor.org/info/rfc5440>. <https://www.rfc-editor.org/info/rfc5440>.
[RFC5462] Andersson, L. and R. Asati, "Multiprotocol Label Switching [RFC5462] Andersson, L. and R. Asati, "Multiprotocol Label Switching
(MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic (MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic
Class" Field", RFC 5462, DOI 10.17487/RFC5462, February Class" Field", RFC 5462, DOI 10.17487/RFC5462, February
2009, <https://www.rfc-editor.org/info/rfc5462>. 2009, <https://www.rfc-editor.org/info/rfc5462>.
[RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre, [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
"Recommendations for Secure Use of Transport Layer Writing an IANA Considerations Section in RFCs", BCP 26,
Security (TLS) and Datagram Transport Layer Security RFC 8126, DOI 10.17487/RFC8126, June 2017,
(DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May <https://www.rfc-editor.org/info/rfc8126>.
2015, <https://www.rfc-editor.org/info/rfc7525>.
[RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", BCP 205,
RFC 7942, DOI 10.17487/RFC7942, July 2016,
<https://www.rfc-editor.org/info/rfc7942>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path [RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
Computation Element Communication Protocol (PCEP) Computation Element Communication Protocol (PCEP)
Extensions for Stateful PCE", RFC 8231, Extensions for Stateful PCE", RFC 8231,
DOI 10.17487/RFC8231, September 2017, DOI 10.17487/RFC8231, September 2017,
<https://www.rfc-editor.org/info/rfc8231>. <https://www.rfc-editor.org/info/rfc8231>.
skipping to change at page 22, line 22 skipping to change at line 892
Decraene, B., Litkowski, S., and R. Shakir, "Segment Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>. July 2018, <https://www.rfc-editor.org/info/rfc8402>.
[RFC8664] Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W., [RFC8664] Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
and J. Hardwick, "Path Computation Element Communication and J. Hardwick, "Path Computation Element Communication
Protocol (PCEP) Extensions for Segment Routing", RFC 8664, Protocol (PCEP) Extensions for Segment Routing", RFC 8664,
DOI 10.17487/RFC8664, December 2019, DOI 10.17487/RFC8664, December 2019,
<https://www.rfc-editor.org/info/rfc8664>. <https://www.rfc-editor.org/info/rfc8664>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer, [RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
D., Matsushima, S., and Z. Li, "Segment Routing over IPv6 D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
(SRv6) Network Programming", RFC 8986, (SRv6) Network Programming", RFC 8986,
DOI 10.17487/RFC8986, February 2021, DOI 10.17487/RFC8986, February 2021,
<https://www.rfc-editor.org/info/rfc8986>. <https://www.rfc-editor.org/info/rfc8986>.
[RFC9050] Li, Z., Peng, S., Negi, M., Zhao, Q., and C. Zhou, "Path [RFC9050] Li, Z., Peng, S., Negi, M., Zhao, Q., and C. Zhou, "Path
Computation Element Communication Protocol (PCEP) Computation Element Communication Protocol (PCEP)
Procedures and Extensions for Using the PCE as a Central Procedures and Extensions for Using the PCE as a Central
Controller (PCECC) of LSPs", RFC 9050, Controller (PCECC) of LSPs", RFC 9050,
DOI 10.17487/RFC9050, July 2021, DOI 10.17487/RFC9050, July 2021,
<https://www.rfc-editor.org/info/rfc9050>. <https://www.rfc-editor.org/info/rfc9050>.
[I-D.ietf-pce-segment-routing-ipv6] [RFC9603] Li, C., Ed., Kaladharan, P., Sivabalan, S., Koldychev, M.,
Li, C., Negi, M., Sivabalan, S., Koldychev, M., and Y. Zhu, "Path Computation Element Communication
Kaladharan, P., and Y. Zhu, "PCEP Extensions for Segment Protocol (PCEP) Extensions for IPv6 Segment Routing",
Routing leveraging the IPv6 data plane", Work in Progress, RFC 9603, DOI 10.17487/RFC9603, July 2024,
Internet-Draft, draft-ietf-pce-segment-routing-ipv6-12, 6 <https://www.rfc-editor.org/info/rfc9603>.
March 2022, <https://www.ietf.org/internet-drafts/draft-
ietf-pce-segment-routing-ipv6-12.txt>.
14.2. Informative References 12.2. Informative References
[PCE-ID-SPACE]
Li, C., Shi, H., Wang, A., Cheng, W., and C. Zhou, "Path
Computation Element Communication Protocol (PCEP)
extension to advertise the PCE Controlled Identifier
Space", Work in Progress, Internet-Draft, draft-ietf-pce-
controlled-id-space-00, 4 June 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-pce-
controlled-id-space-00>.
[PCEP-SR] Li, C., Chen, M., Cheng, W., Gandhi, R., and Q. Xiong,
"Path Computation Element Communication Protocol (PCEP)
Extension for Path Segment in Segment Routing (SR)", Work
in Progress, Internet-Draft, draft-ietf-pce-sr-path-
segment-09, 26 February 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-pce-sr-
path-segment-09>.
[PCEP-YANG]
Dhody, D., Beeram, V. P., Hardwick, J., and J. Tantsura,
"A YANG Data Model for Path Computation Element
Communications Protocol (PCEP)", Work in Progress,
Internet-Draft, draft-ietf-pce-pcep-yang-25, 21 May 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-pce-
pcep-yang-25>.
[RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path [RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
Computation Element (PCE)-Based Architecture", RFC 4655, Computation Element (PCE)-Based Architecture", RFC 4655,
DOI 10.17487/RFC4655, August 2006, DOI 10.17487/RFC4655, August 2006,
<https://www.rfc-editor.org/info/rfc4655>. <https://www.rfc-editor.org/info/rfc4655>.
[RFC8283] Farrel, A., Ed., Zhao, Q., Ed., Li, Z., and C. Zhou, "An [RFC8283] Farrel, A., Ed., Zhao, Q., Ed., Li, Z., and C. Zhou, "An
Architecture for Use of PCE and the PCE Communication Architecture for Use of PCE and the PCE Communication
Protocol (PCEP) in a Network with Central Control", Protocol (PCEP) in a Network with Central Control",
RFC 8283, DOI 10.17487/RFC8283, December 2017, RFC 8283, DOI 10.17487/RFC8283, December 2017,
<https://www.rfc-editor.org/info/rfc8283>. <https://www.rfc-editor.org/info/rfc8283>.
[RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J., [RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J.,
Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
(SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020, (SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,
<https://www.rfc-editor.org/info/rfc8754>. <https://www.rfc-editor.org/info/rfc8754>.
[I-D.ietf-spring-segment-routing-policy] [RFC9256] Filsfils, C., Talaulikar, K., Ed., Voyer, D., Bogdanov,
Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and A., and P. Mattes, "Segment Routing Policy Architecture",
P. Mattes, "Segment Routing Policy Architecture", Work in RFC 9256, DOI 10.17487/RFC9256, July 2022,
Progress, Internet-Draft, draft-ietf-spring-segment- <https://www.rfc-editor.org/info/rfc9256>.
routing-policy-21, 19 March 2022,
<https://www.ietf.org/archive/id/draft-ietf-spring-
segment-routing-policy-21.txt>.
[I-D.ietf-pce-pcep-yang] Acknowledgements
Dhody, D., Hardwick, J., Beeram, V. P., and J. Tantsura,
"A YANG Data Model for Path Computation Element
Communications Protocol (PCEP)", Work in Progress,
Internet-Draft, draft-ietf-pce-pcep-yang-18, 25 January
2022, <https://www.ietf.org/archive/id/draft-ietf-pce-
pcep-yang-18.txt>.
[I-D.li-pce-controlled-id-space] We would like to thank Milos Fabian, Mrinmoy Das, Andrew Stone, Tom
Li, C., Chen, M., Wang, A., Cheng, W., and C. Zhou, "PCE Petch, Aijun Wang, Olivier Dugeon, and Adrian Farrel for their
Controlled ID Space", Work in Progress, Internet-Draft, valuable comments.
draft-li-pce-controlled-id-space-10, 24 February 2022,
<https://www.ietf.org/archive/id/draft-li-pce-controlled-
id-space-10.txt>.
[I-D.ietf-pce-sr-path-segment] Thanks to Julien Meuric for shepherding. Thanks to John Scudder for
Li, C., Chen, M., Cheng, W., Gandhi, R., and Q. Xiong, the AD review.
"Path Computation Element Communication Protocol (PCEP)
Extension for Path Segment in Segment Routing (SR)", Work
in Progress, Internet-Draft, draft-ietf-pce-sr-path-
segment-05, 13 February 2022,
<https://www.ietf.org/archive/id/draft-ietf-pce-sr-path-
segment-05.txt>.
Appendix A. Contributor Addresses Thanks to Theresa Enghardt for the GENART review.
Thanks to Martin Vigoureux, Benjamin Kaduk, Eric Vyncke, Lars Eggert,
Murray Kucherawy, and Erik Kline for the IESG reviews.
Contributors
Jonathan Hardwick Jonathan Hardwick
Microsoft Microsoft
United Kingdom United Kingdom
Email: jonhardwick@microsoft.com
EMail: jonhardwick@microsoft.com
Dhruv Dhody Dhruv Dhody
Huawei Technologies Huawei Technologies
Divyashree Techno Park, Whitefield Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560066 Bangalore 560066
Karnataka
India India
Email: dhruv.ietf@gmail.com
EMail: dhruv.ietf@gmail.com
Mahendra Singh Negi Mahendra Singh Negi
RtBrick India RtBrick India
N-17L, Floor-1, 18th Cross Rd, HSR Layout Sector-3 N-17L, Floor-1, 18th Cross Rd, HSR Layout Sector-3
Bangalore, Karnataka 560102 Bangalore 560102
Karnataka
India India
Email: mahend.ietf@gmail.com
EMail: mahend.ietf@gmail.com
Mike Koldychev Mike Koldychev
Cisco Systems, Inc. Cisco Systems, Inc.
2000 Innovation Drive 2000 Innovation Drive
Kanata, Ontario K2K 3E8 Kanata Ontario K2K 3E8
Canada Canada
Email: mkoldych@cisco.com Email: mkoldych@cisco.com
Zafar Ali Zafar Ali
Cisco Systems, Inc. Cisco Systems, Inc.
Email: zali@cisco.com Email: zali@cisco.com
Authors' Addresses Authors' Addresses
Siva Sivabalan Siva Sivabalan
Ciena Corporation Ciena Corporation
Email: msiva282@gmail.com Email: msiva282@gmail.com
Clarence Filsfils Clarence Filsfils
Cisco Systems, Inc. Cisco Systems, Inc.
Pegasus Parc Pegasus Parc
BRABANT 1831 De kleetlaan 6a De Kleetlaan 6a
1831 Brabant
Belgium Belgium
Email: cfilsfil@cisco.com Email: cfilsfil@cisco.com
Jeff Tantsura Jeff Tantsura
Microsoft Corporation Nvidia
Email: jefftant.ietf@gmail.com Email: jefftant.ietf@gmail.com
Stefano Previdi Stefano Previdi
Huawei Technologies Huawei Technologies
Email: stefano@previdi.net Email: stefano@previdi.net
Cheng Li (editor) Cheng Li (editor)
Huawei Technologies Huawei Technologies
Huawei Campus, No. 156 Beiqing Rd. Huawei Campus, No. 156 Beiqing Rd.
Beijing Beijing
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