< draft-ietf-pce-binding-label-sid-07.txt   draft-ietf-pce-binding-label-sid-08.txt >
PCE Working Group S. Sivabalan PCE Working Group S. Sivabalan
Internet-Draft Ciena Corporation Internet-Draft Ciena Corporation
Intended status: Standards Track C. Filsfils Intended status: Standards Track C. Filsfils
Expires: August 24, 2021 Cisco Systems, Inc. Expires: October 16, 2021 Cisco Systems, Inc.
J. Tantsura J. Tantsura
Apstra, Inc. Juniper Networks
S. Previdi S. Previdi
C. Li C. Li
Huawei Technologies Huawei Technologies
February 20, 2021 April 14, 2021
Carrying Binding Label/Segment-ID in PCE-based Networks. Carrying Binding Label/Segment Identifier in PCE-based Networks.
draft-ietf-pce-binding-label-sid-07 draft-ietf-pce-binding-label-sid-08
Abstract Abstract
In order to provide greater scalability, network opacity, and service In order to provide greater scalability, network opacity, and service
independence, Segment Routing (SR) utilizes a Binding Segment independence, Segment Routing (SR) utilizes a Binding Segment
Identifier (BSID). It is possible to associate a BSID to RSVP-TE Identifier (BSID). It is possible to associate a BSID to an RSVP-TE
signaled Traffic Engineering Label Switching Path or binding Segment- signaled Traffic Engineering Label Switching Path or an SR Traffic
ID (SID) to SR Traffic Engineering path. Such a binding label/SID Engineering path. The BSID can be used by an upstream node for
can be used by an upstream node for steering traffic into the steering traffic into the appropriate TE path to enforce SR policies.
appropriate TE path to enforce SR policies. This document proposes This document specifies the binding value as an MPLS label or Segment
an approach for reporting binding label/SID to Path Computation Identifier. It further specify an approach for reporting binding
Element (PCE) for supporting PCE-based Traffic Engineering policies. label/SID by a Path Computation Client (PCC) to the Path Computation
Element (PCE) to support PCE-based Traffic Engineering policies.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 24, 2021. This Internet-Draft will expire on October 16, 2021.
Copyright Notice Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 5
3. Path Binding TLV . . . . . . . . . . . . . . . . . . . . . . 6 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. SRv6 Endpoint Behavior and SID Structure . . . . . . . . 7 4. Path Binding TLV . . . . . . . . . . . . . . . . . . . . . . 6
4. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.1. SRv6 Endpoint Behavior and SID Structure . . . . . . . . 7
5. Binding SID in SR-ERO . . . . . . . . . . . . . . . . . . . . 10 5. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6. Binding SID in SRv6-ERO . . . . . . . . . . . . . . . . . . . 10 6. Binding SID in SR-ERO . . . . . . . . . . . . . . . . . . . . 10
7. PCE Allocation of Binding SID . . . . . . . . . . . . . . . . 10 7. Binding SID in SRv6-ERO . . . . . . . . . . . . . . . . . . . 11
8. Implementation Status . . . . . . . . . . . . . . . . . . . . 12 8. PCE Allocation of Binding label/SID . . . . . . . . . . . . . 11
8.1. Huawei . . . . . . . . . . . . . . . . . . . . . . . . . 12 9. Implementation Status . . . . . . . . . . . . . . . . . . . . 13
8.2. Cisco . . . . . . . . . . . . . . . . . . . . . . . . . . 13 9.1. Huawei . . . . . . . . . . . . . . . . . . . . . . . . . 13
9. Security Considerations . . . . . . . . . . . . . . . . . . . 13 9.2. Cisco . . . . . . . . . . . . . . . . . . . . . . . . . . 13
10. Manageability Considerations . . . . . . . . . . . . . . . . 13 10. Security Considerations . . . . . . . . . . . . . . . . . . . 14
10.1. Control of Function and Policy . . . . . . . . . . . . . 14 11. Manageability Considerations . . . . . . . . . . . . . . . . 14
10.2. Information and Data Models . . . . . . . . . . . . . . 14 11.1. Control of Function and Policy . . . . . . . . . . . . . 14
10.3. Liveness Detection and Monitoring . . . . . . . . . . . 14 11.2. Information and Data Models . . . . . . . . . . . . . . 14
10.4. Verify Correct Operations . . . . . . . . . . . . . . . 14 11.3. Liveness Detection and Monitoring . . . . . . . . . . . 14
10.5. Requirements On Other Protocols . . . . . . . . . . . . 14 11.4. Verify Correct Operations . . . . . . . . . . . . . . . 15
10.6. Impact On Network Operations . . . . . . . . . . . . . . 14 11.5. Requirements On Other Protocols . . . . . . . . . . . . 15
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 11.6. Impact On Network Operations . . . . . . . . . . . . . . 15
11.1. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . 14 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
11.1.1. TE-PATH-BINDING TLV . . . . . . . . . . . . . . . . 15 12.1. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . 15
11.2. LSP Object . . . . . . . . . . . . . . . . . . . . . . . 15 12.1.1. TE-PATH-BINDING TLV . . . . . . . . . . . . . . . . 15
11.3. PCEP Error Type and Value . . . . . . . . . . . . . . . 16 12.2. LSP Object . . . . . . . . . . . . . . . . . . . . . . . 16
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 16 12.3. PCEP Error Type and Value . . . . . . . . . . . . . . . 16
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 16 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17
13.1. Normative References . . . . . . . . . . . . . . . . . . 16 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
13.2. Informative References . . . . . . . . . . . . . . . . . 18 14.1. Normative References . . . . . . . . . . . . . . . . . . 17
Appendix A. Contributor Addresses . . . . . . . . . . . . . . . 19 14.2. Informative References . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19 Appendix A. Contributor Addresses . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20
1. Introduction 1. Introduction
A PCE can compute Traffic Engineering paths (TE paths) through a A Path Computation Element (PCE) can compute Traffic Engineering
network that are subject to various constraints. Currently, TE paths paths (TE paths) through a network where those paths are subject to
are either set up using the RSVP-TE signaling protocol or Segment various constraints. Currently, TE paths are either set up using the
Routing (SR). We refer to such paths as RSVP-TE paths and SR-TE RSVP-TE signaling protocol or Segment Routing (SR). We refer to such
paths respectively in this document. paths as RSVP-TE paths and SR-TE paths respectively in this document.
As per [RFC8402] SR allows a headend node to steer a packet flow As per [RFC8402] SR allows a headend node to steer a packet flow
along any path. The headend node is said to steer a flow into an along any path. The headend node is said to steer a flow into an
Segment Routing Policy (SR Policy). Further, as per Segment Routing Policy (SR Policy). Further, as per
[I-D.ietf-spring-segment-routing-policy], an SR Policy is a framework [I-D.ietf-spring-segment-routing-policy], an SR Policy is a framework
that enables instantiation of an ordered list of segments on a node that enables instantiation of an ordered list of segments on a node
for implementing a source routing policy with a specific intent for for implementing a source routing policy with a specific intent for
traffic steering from that node. traffic steering from that node.
As described in [RFC8402], Binding Segment Identifier (BSID) is bound As described in [RFC8402], a Binding Segment Identifier (BSID) is
to an Segment Routed (SR) Policy, instantiation of which may involve bound to a Segment Routed (SR) Policy, instantiation of which may
a list of SIDs. Any packets received with an active segment equal to involve a list of SIDs. Any packets received with an active segment
BSID are steered onto the bound SR Policy. A BSID may be either a equal to a BSID are steered onto the bound SR Policy. A BSID may be
local (SR Local Block (SRLB)) or a global (SR Global Block (SRGB)) either a local (SR Local Block (SRLB)) or a global (SR Global Block
SID. As per Section 6.4 of [I-D.ietf-spring-segment-routing-policy] (SRGB)) SID. As per Section 6.4 of
a BSID can also be associated with any type of interfaces or tunnel [I-D.ietf-spring-segment-routing-policy] a BSID can also be
to enable the use of a non-SR interface or tunnels as segments in a associated with any type of interfaces or tunnel to enable the use of
SID-list. a non-SR interface or tunnel as a segment in a SID-list. In this
document, binding label/SID is used to generalize the allocation of
binding value for both SR and non-SR paths.
[RFC5440] describes the Path Computation Element Protocol (PCEP) for [RFC5440] describes the Path Computation Element Protocol (PCEP) for
communication between a Path Computation Client (PCC) and a PCE or communication between a Path Computation Client (PCC) and a PCE or
between a pair of PCEs as per [RFC4655]. [RFC8231] specifies between a pair of PCEs as per [RFC4655]. [RFC8231] specifies
extension to PCEP that allows a PCC to delegate its LSPs to a extensions to PCEP that allow a PCC to delegate its Label Switched
stateful PCE. A stateful PCE can then update the state of LSPs Paths (LSPs) to a stateful PCE. A stateful PCE can then update the
delegated to it. [RFC8281] specifies a mechanism allowing a PCE to state of LSPs delegated to it. [RFC8281] specifies a mechanism
dynamically instantiate an LSP on a PCC by sending the path and allowing a PCE to dynamically instantiate an LSP on a PCC by sending
characteristics. The PCEP extension to setup and maintain SR-TE the path and characteristics.
paths is specified in [RFC8664].
[RFC8664] provides a mechanism for a network controller (acting as a [RFC8664] provides a mechanism for a network controller (acting as a
PCE) to instantiate candidate paths for an SR Policy onto a head-end PCE) to instantiate SR-TE paths (candidate paths) for an SR Policy
node (acting as a PCC) using PCEP. For more information on the SR onto a head-end node (acting as a PCC) using PCEP. For more
Policy Architecture, see [I-D.ietf-spring-segment-routing-policy]. information on the SR Policy Architecture, see
[I-D.ietf-spring-segment-routing-policy].
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, it may be desirable to report the binding label or SID up TE paths, it may be desirable for PCC to report the binding label/
to the stateful PCE for the purpose of enforcing end-to-end TE/SR SID to the stateful PCE for the purpose of enforcing end-to-end TE/SR
policy. A sample Data Center (DC) use-case is illustrated in the policy. A sample Data Center (DC) use-case is illustrated in the
following diagram. In the MPLS DC network, an SR LSP (without Figure 1. In the MPLS DC network, an SR LSP (without traffic
traffic engineering) is established using a prefix SID advertised by engineering) is established using a prefix SID advertised by BGP (see
BGP (see [RFC8669]). In IP/MPLS WAN, an SR-TE LSP is setup using the [RFC8669]). In the IP/MPLS WAN, an SR-TE LSP is set up using the
PCE. The list of SIDs of the SR-TE LSP is {A, B, C, D}. The gateway PCE. The list of SIDs of the SR-TE LSP is {A, B, C, D}. The gateway
node 1 (which is the PCC) allocates a binding SID X and reports it to node 1 (which is the PCC) allocates a binding SID X and reports it to
the PCE. In order for the access node to steer the traffic over the the PCE. In order for the access node to steer the traffic over the
SR-TE LSP, the PCE passes the SID stack {Y, X} where Y is the prefix SR-TE LSP, the PCE passes the SID stack {Y, X} where Y is the prefix
SID of the gateway node-1 to the access node. In the absence of the SID of the gateway node-1 to the access node. In the absence of the
binding SID X, the PCE should pass the SID stack {Y, A, B, C, D} to binding SID X, the PCE should pass the SID stack {Y, A, B, C, D} to
the access node. This example also illustrates the additional the access node. This example also illustrates the additional
benefit of using the binding SID to reduce the number of SIDs imposed benefit of using the binding SID to reduce the number of SIDs imposed
on the access nodes with a limited forwarding capacity. on the access nodes with a limited forwarding capacity.
skipping to change at page 5, line 12 skipping to change at page 5, line 10
specified binding value, it reports the binding value to the PCE. specified binding value, it reports the binding value to the PCE.
Otherwise, the PCC sends an error message to the PCE indicating the Otherwise, the PCC sends an error message to the PCE indicating the
cause of the failure. A local policy or configuration at the PCC cause of the failure. A local policy or configuration at the PCC
SHOULD dictate if the binding label/SID needs to be assigned. SHOULD dictate if the binding label/SID needs to be assigned.
In this document, we introduce a new OPTIONAL TLV that a PCC can use In this document, we introduce a new OPTIONAL TLV that a PCC can use
in order to report the binding label/SID associated with a TE LSP, or in order to report the binding label/SID associated with a TE LSP, or
a PCE to request a PCC to allocate a specific binding label/SID a PCE to request a PCC to allocate a specific binding label/SID
value. This TLV is intended for TE LSPs established using RSVP-TE, value. This TLV is intended for TE LSPs established using RSVP-TE,
SR, or any other future method. Also, in the case of SR-TE LSPs, the SR, or any other future method. Also, in the case of SR-TE LSPs, the
TLV can carry a binding MPLS label (for SR-TE path with MPLS data- TLV can carry a binding label (for SR-TE path with MPLS data-plane)
plane) or a binding IPv6 SID (e.g., IPv6 address for SR-TE paths with or a binding IPv6 SID (e.g., IPv6 address for SR-TE paths with IPv6
IPv6 data-plane). Binding value means either MPLS label or SID data-plane). Throughout this document, the term "binding value"
throughout this document. means either an MPLS label or SID.
Additionally, to support the PCE based central controller [RFC8283] Additionally, to support the PCE based central controller [RFC8283]
operation where the PCE would take responsibility for managing some operation where the PCE would take responsibility for managing some
part of the MPLS label space for each of the routers that it part of the MPLS label space for each of the routers that it
controls, the PCE could directly make the binding label/SID controls, the PCE could directly make the binding label/SID
allocation and inform the PCC. See Section 7 for details. allocation and inform the PCC. See Section 8 for details.
2. Terminology 2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Terminology
The following terminologies are used in this document: The following terminologies are used in this document:
BSID: Binding Segment Identifier. BSID: Binding Segment Identifier.
LER: Label Edge Router.
LSP: Label Switched Path. LSP: Label Switched Path.
LSR: Label Switching Router.
PCC: Path Computation Client. PCC: Path Computation Client.
PCE: Path Computation Element PCE: Path Computation Element
PCEP: Path Computation Element Protocol. PCEP: Path Computation Element 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.
SRGB: Segment Routing Global Block.
SRLB: Segment Routing Local Block.
TLV: Type, Length, and Value. TLV: Type, Length, and Value.
3. Path Binding TLV 4. Path Binding TLV
The new optional TLV is called "TE-PATH-BINDING TLV" (whose format is The new optional TLV is called "TE-PATH-BINDING TLV" (whose format is
shown in the figure below) is defined to carry the binding label or shown in the Figure 2) is defined to carry the binding label/SID for
SID for a TE path. This TLV is associated with the LSP object a TE path. This TLV is associated with the LSP object specified in
specified in ([RFC8231]). The type of this TLV is to be allocated by [RFC8231]. This TLV can also be carried in the PCEP-ERROR object
IANA. [RFC5440] in case of error. Multiple instance of TE-PATH-BINDING
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.
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 | Length | | Type | 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 TE-PATH-BINDING TLV is a generic TLV such that it is able to carry
MPLS label binding as well as SRv6 Binding SID. It is formatted binding label/SID (i.e. MPLS label or SRv6 SID). It is formatted
according to the rules specified in [RFC5440]. according to the rules specified in [RFC5440]. The value portion of
the TLV comprise of:
Binding Type (BT): A one-octet field identifies the type of binding Binding Type (BT): A one-octet field identifies the type of binding
included in the TLV. This document specifies the following BT included in the TLV. This document specifies the following BT
values: values:
o BT = 0: The binding value is an MPLS label carried in the format o BT = 0: The binding value is a 20-bit MPLS label value. The TLV
specified in [RFC5462] where only the label value is valid, and is padded to 4-bytes alignment. The Length MUST be set to 7 and
other fields MUST be considered invalid. The Length MUST be set first 20 bits are used to encode the MPLS label value.
to 7.
o BT = 1: Similar to the case where BT is 0 except that all the o BT = 1: The binding value is a 32-bit MPLS label stack entry as
fields on the MPLS label entry are set on transmission. However, per [RFC3032] with Label, TC [RFC5462], S, and TTL values encoded.
the receiver MAY choose to override TC, S, and TTL values Note that the receiver MAY choose to override TC, S, and TTL
according its local policy. The Length MUST be set to 8. values according to its local policy. The Length MUST be set to
8.
o BT = 2: The binding value is an SRv6 SID with a format of a 16 o BT = 2: The binding value is an SRv6 SID with a format of a 16
octet IPv6 address, representing the binding SID for SRv6. The octet IPv6 address, representing the binding SID for SRv6. The
Length MUST be set to 20. Length MUST be set to 20.
o BT = 3: The binding value is a 24 octet field, defined in o BT = 3: The binding value is a 24 octet field, defined in
Section 3.1, 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.
Flags: 1 octet of flags. Following flags are defined in the new Section 12.1.1 defines the IANA registry used to maintain all these
binding types as well as any future ones. Note that, multiple TE-
PATH-BINDING TLVs with different Binding Types MAY be present for the
same LSP.
Flags: 1 octet of flags. Following flag is defined in the new
registry "TE-PATH-BINDING TLV Flag field" as described in registry "TE-PATH-BINDING TLV Flag field" as described in
Section 11.1.1: Section 12.1.1:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| |I|S| |R| |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
where: Figure 3: Flags
o S-Flag: This flag encodes the "Specified-BSID-only" behavior. It where:
is used as described in Section 6.2.3 of
[I-D.ietf-spring-segment-routing-policy].
o I-Flag: This flag encodes the "Drop Upon Invalid" behavior. It is o R (Removal - 1 bit): When set, the requesting PCEP peer requires
used as described in Section 8.2 of the removal of the binding value for the LSP. When unset, the
[I-D.ietf-spring-segment-routing-policy]. PCEP peer indicates that the binding value is added or retained
for the LSP. This flag is used in the PCRpt and PCUpd messages.
It is ignored in other PCEP messages.
o Unassigned bits MUST be set to 0 while sending and ignored on o The unassigned flags MUST be set to 0 while sending and ignored on
receipt. 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 to
a 4-octet boundary. For the BT as 0, the 20 bits represent the MPLS a 4-octet boundary. For the BT as 0, the 20 bits represent the MPLS
label. For the BT as 1, the 32-bits represent the label stack entry label. For the BT as 1, the 32-bits represent the MPLS label stack
as per [RFC5462]. For the BT as 2, the 128-bits represent the SRv6 entry as per [RFC3032]. For the BT as 2, the 128-bits represent the
SID. For the BT as 3, the Binding Value contains SRv6 Endpoint SRv6 SID. For the BT as 3, the Binding Value also contains the SRv6
Behavior and SID Structure, defined in Section 3.1. Endpoint Behavior and SID Structure, defined in Section 4.1.
3.1. SRv6 Endpoint Behavior and SID Structure 4.1. SRv6 Endpoint Behavior and SID Structure
Carried as the Binding Value in the TE-PATH-BINDING TLV when the BT This section specify the format of the Binding Value in the TE-PATH-
is set to 3. Applicable for SRv6 Binding SIDs BINDING TLV when the BT is set to 3 for the SRv6 Binding SIDs
[I-D.ietf-spring-srv6-network-programming]. [RFC8986], as 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
Reserved: 2 octets. MUST be set to 0 on transmit and ignored on The Binding Value consist of:
receipt.
Endpoint Behavior: 2 octets. The Endpoint Behavior code point for o SRv6 Binding SID: 16 octets. The 128-bits IPv6 address,
this SRv6 SID as defined in section 9.2 of representing the binding SID for SRv6.
[I-D.ietf-spring-srv6-network-programming]. When set with the value
0, the choice of behavior is considered unset.
LB Length: 1 octet. SRv6 SID Locator Block length in bits. o Reserved: 2 octets. It MUST be set to 0 on transmit and ignored
on receipt.
LN Length: 1 octet. SRv6 SID Locator Node length in bits. o Endpoint Behavior: 2 octets. The Endpoint Behavior code point for
this SRv6 SID as per the IANA subregistry called "SRv6 Endpoint
Behaviors", created by [RFC8986]. When the field is set with the
value 0, the endpoint behavior is considered unknown.
Function Length: 1 octet. SRv6 SID Function length in bits. o The following fields are used to advertise the length of each
individual part of the SRv6 SID as defined in [RFC8986]:
Argument Length: 1 octet. SRv6 SID Arguments length in bits. * LB Length: 1 octet. SRv6 SID Locator Block length in bits.
4. Operation * LN Length: 1 octet. SRv6 SID Locator Node length in bits.
* Function Length: 1 octet. SRv6 SID Function length in bits.
* Argument Length: 1 octet. SRv6 SID Arguments length in bits.
5. Operation
The binding value is allocated by the PCC and reported to a PCE via The binding value is allocated by the PCC and reported to a PCE via
PCRpt message. If a PCE does not recognize the TE-PATH-BINDING TLV, PCRpt message. If a PCE does not recognize the TE-PATH-BINDING TLV,
it would ignore the TLV in accordance with ([RFC5440]). If a PCE it would ignore the TLV in accordance with [RFC5440]. If a PCE
recognizes the TLV but does not support the TLV, it MUST send PCErr recognizes the TLV but does not support the TLV, it MUST send PCErr
with Error-Type = 2 (Capability not supported). with Error-Type = 2 (Capability not supported).
If a TE-PATH-BINDING TLV is absent in the PCRpt message, PCE MUST
assume that the corresponding LSP does not have any binding. If a
PCE recognizes an invalid binding value (e.g., label value from the
reserved label space when MPLS label binding is used), it MUST send
the PCErr message with Error-Type = 10 ("Reception of an invalid
object") and Error Value = 2 ("Bad label value") as specified in
[RFC8664].
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. the given LSP. In the case of multiple TE-PATH-BINDING TLVs,
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
and the resulting PCErr message MAY include the offending TE-PATH-
BINDING TLV in the PCEP-ERROR object.
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
Error-Type = 10 ("Reception of an invalid object") and Error Value =
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, instead of 2. The choice of by setting the BT (Binding Type) to 3. This enables the sender to
interpreting SRv6 Endpoint Behavior and SID Structure when none is have control of the SRv6 Endpoint Behavior and SID Structure. A
explicitly specified is left up to the implementation. sender MAY choose to set the BT to 2, in which case the receiving
implementation chooses how to interpret the SRv6 Endpoint Behavior
If a PCE requires a PCC to allocate a specific binding value, it may and SID Structure according to local policy.
do so by sending a PCUpd or PCInitiate message containing a TE-PATH-
BINDING TLV. If the value can be successfully allocated, the PCC
reports the binding value to the PCE. If the PCC considers the
binding value specified by the PCE invalid, it MUST send a PCErr
message with Error-Type = TBD2 ("Binding label/SID failure") and
Error Value = TBD3 ("Invalid SID"). If the binding value is valid,
but the PCC is unable to allocate the binding value, it MUST send a
PCErr message with Error-Type = TBD2 ("Binding label/SID failure")
and Error Value = TBD4 ("Unable to allocate the specified label/
SID").
If a PCC receives TE-PATH-BINDING TLV in any message other than PCUpd If a PCC wishes to withdraw a previously reported binding value, it
or PCInitiate, it MUST close the corresponding PCEP session with the MUST send a PCRpt message with the specific TE-PATH-BINDING TLV with
reason "Reception of a malformed PCEP message" (according to R flag set to 1. If a PCC wishes to modify a previously reported
[RFC5440]). Similarly, if a PCE receives a TE-PATH-BINDING TLV in binding, it MUST withdraw the old binding value (with R flag set in
any message other than a PCRpt or if the TE-PATH-BINDING TLV is the old TE-PATH-BINDING TLV) and include a new TE-PATH-BINDING TLV
associated with any object other than LSP object, the PCE MUST close containing the new binding value. Note that, other instances of TE-
the corresponding PCEP session with the reason "Reception of a PATH-BINDING TLVs that are unchanged MAY also be included.
malformed PCEP message" (according to [RFC5440]).
If a PCC wishes to withdraw or modify a previously reported binding If a PCE requires a PCC to allocate a specific binding value(s), it
value, it MUST send a PCRpt message without any TE-PATH-BINDING TLV may do so by sending a PCUpd or PCInitiate message containing a TE-
or with the TE-PATH-BINDING TLV containing the new binding value PATH-BINDING TLV(s). If the value(s) can be successfully allocated,
respectively. the PCC reports the binding value(s) to the PCE. If the PCC
considers the binding value specified by the PCE invalid, it MUST
send a PCErr message with Error-Type = TBD2 ("Binding label/SID
failure") and Error Value = TBD3 ("Invalid SID"). If the binding
value is valid, but the PCC is unable to allocate the binding value,
it MUST send a PCErr message with Error-Type = TBD2 ("Binding label/
SID failure") and Error Value = TBD4 ("Unable to allocate the
specified binding value"). Note that in case of an error, the PCC
rejects the PCUpd or PCInitiate message in its entirety and can carry
the offending TE-PATH-BINDING TLV in the PCEP-ERROR object.
If a PCE wishes to modify a previously requested binding value, it If a PCE wishes to request withdrawal of a previously reported
MUST send a PCUpd message with TE-PATH-BINDING TLV containing the new binding value, it MUST send a PCUpd message with the specific TE-
binding value. The absence of TE-PATH-BINDING TLV in PCUpd message PATH-BINDING TLV with R flag set to 1. If a PCE wishes to modify a
means that the PCE does not specify a binding value in which case the previously requested binding value, it MUST request withdrawal of the
binding value allocation is governed by the PCC's local policy. old binding value (with R flag set in the old TE-PATH-BINDING TLV)
and include a new TE-PATH-BINDING TLV containing the new binding
value.
If a PCC receives a valid binding value from a PCE which is different In some cases, a stateful PCE can request the PCC to allocate any
than the current binding value, it MUST try to allocate the new binding value. It instructs the PCC by sending a PCUpd message
value. If the new binding value is successfully allocated, the PCC containing an empty TE-PATH-BINDING TLV, i.e., no binding value is
MUST report the new value to the PCE. Otherwise, it MUST send a specified (making the length field of the TLV as 4). A PCE can also
PCErr message with Error-Type = TBD2 ("Binding label/SID failure") request PCC to allocate a binding value at the time of initiation by
and Error Value = TBD4 ("Unable to allocate the specified label/ sending a PCInitiate message with an empty TE-PATH-BINDING TLV. Only
one such instance of empty TE-PATH-BINDING TLV SHOULD be included in
the LSP object and others ignored on receipt. If the PCC is unable
to allocate a new binding value as per the specified BT, it MUST send
a PCErr message with Error-Type = TBD2 ("Binding label/SID failure")
and Error-Value = TBD5 ("Unable to allocate a new binding label/
SID"). SID").
In some cases, a stateful PCE can request the PCC to allocate a As previously noted, if a message contains an invalid TE-PATH-BINDING
binding value. It may do so by sending a PCUpd message containing an TLV that leads to an error condition, the whole message is rejected
empty TE-PATH-BINDING TLV, i.e., no binding value is specified including any other valid instances of TE-PATH-BINDING TLVs, if any.
(making the length field of the TLV as 4). A PCE can also request The resulting error message MAY include the offending TE-PATH-BINDING
PCC to allocate a binding value at the time of initiation by sending TLV in the PCEP-ERROR object.
a PCInitiate message with an empty TE-PATH-BINDING TLV. If the PCC
is unable to allocate a binding value, it MUST send a PCErr message
with Error-Type = TBD2 ("Binding label/SID failure") and Error-Value
= TBD5 ("Unable to allocate label/SID").
5. Binding SID in SR-ERO If a PCC receives a TE-PATH-BINDING TLV in any message other than
PCUpd or PCInitiate, it MUST close the corresponding PCEP session
with the reason "Reception of a malformed PCEP message" (according to
[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
associated with any object other than an LSP or PCEP-ERROR object,
the PCE MUST close the corresponding PCEP session with the reason
"Reception of a malformed PCEP message" (according to [RFC5440]).
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
corresponding LSP does not have any binding. Similarly, if TE-PATH-
BINDING TLV is absent in the PCUpd message and no binding values were
reported before, the PCC's local policy dictates how the binding
allocations are made for a given LSP.
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 a new ERO subobject "SR-ERO subobject" capable of [RFC8664] defines a new ERO subobject "SR-ERO subobject" capable of
carrying a SID as well as the identity of the node/adjacency (NAI) carrying a SID as well as the identity of the node/adjacency (NAI)
represented by the SID. The NAI Type (NT) field indicates the type represented by the SID. The NAI Type (NT) field indicates the type
and format of the NAI contained in the SR-ERO. In case of binding and format of the NAI contained in the SR-ERO. In case of binding
SID, the NAI MUST NOT be included and NT MUST be set to zero. So as SID, the NAI MUST NOT be included and NT MUST be set to zero. So as
per Section 5.2.1 of [RFC8664], for NT=0, the F bit is set to 1, the per Section 5.2.1 of [RFC8664], for NT=0, the F bit is set to 1, the
S bit needs to be zero and the Length is 8. Further, the M bit is S bit needs to be zero and the Length is 8. Further, the M bit is
set. If these conditions are not met, the entire ERO MUST be set. If these conditions are not met, the entire ERO MUST be
considered invalid and a PCErr message is sent with Error-Type = 10 considered invalid and a PCErr message is sent by the PCC with Error-
("Reception of an invalid object") and Error-Value = 11 ("Malformed Type = 10 ("Reception of an invalid object") and Error-Value = 11
object"). ("Malformed object").
6. Binding SID in SRv6-ERO 7. Binding SID in SRv6-ERO
[RFC8664] defines a new ERO subobject "SRv6-ERO subobject" for SRv6 [I-D.ietf-pce-segment-routing-ipv6] defines a new ERO subobject
SID. The NAI MUST NOT be included and NT MUST be set to zero. So as "SRv6-ERO subobject" for an SRv6 SID. As stated in Section 6, in
per Section 5.2.1 of [RFC8664], for NT=0, the F bit is set to 1, the case of binding SID, the NAI is not included and NT is set to zero
S bit needs to be zero and the Length is 24. If these conditions are i.e., NT=0, the F bit is set to 1, the S bit needs to be zero and the
not met, the entire ERO is considered invalid and a PCErr message is Length is 24 [I-D.ietf-pce-segment-routing-ipv6]. As per [RFC8664],
sent with Error-Type = 10 ("Reception of an invalid object") and if these conditions are not met, the entire ERO is considered invalid
Error-Value = 11 ("Malformed object") (as per [RFC8664]). and a PCErr message is sent by the PCC with Error-Type = 10
("Reception of an invalid object") and Error-Value = 11 ("Malformed
object").
7. PCE Allocation of Binding SID 8. PCE Allocation of Binding label/SID
Section 4 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 specify an message containing a TE-PATH-BINDING TLV. This section specifies an
OPTIONAL feature for the PCE to allocate the binding label on its own OPTIONAL feature for the PCE to allocate the binding label/SID on its
accord in the case where the PCE also controls the label space of the own accord in the case where the PCE also controls the label space of
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 4) 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. [I-D.ietf-pce-pcep-extension-for-pce-controller] specifies and PCC. [I-D.ietf-pce-pcep-extension-for-pce-controller] specifies
the procedures and PCEP extensions for using the PCE as the central the procedures and PCEP extensions for using the PCE as the central
controller. controller.
For an implementation that supports PCECC operations as per For an implementation that supports PCECC operations as per
[I-D.ietf-pce-pcep-extension-for-pce-controller], the binding label/ [I-D.ietf-pce-pcep-extension-for-pce-controller], the binding label/
SID MAY also be allocated by the PCE itself. Both peers need to SID MAY also be allocated by the PCE itself. Both peers need to
exchange the PCECC capability as described in exchange the PCECC capability as described in
[I-D.ietf-pce-pcep-extension-for-pce-controller] before PCE could [I-D.ietf-pce-pcep-extension-for-pce-controller] before the PCE can
allocate the binding label/SID on its own. 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
the allocation needs to be made by the PCE: the allocation needs to be made by the PCE:
o P (PCE-allocated binding label/SID - TBD6): If the bit is set to o P (PCE-allocated binding label/SID): If the bit is set to 1, it
1, it indicates that the PCC requests PCE to make allocations for indicates that the PCC requests PCE to make allocations for this
this LSP. The TLV in LSP object identifies what should be LSP. The TE-PATH-BINDING TLV in the LSP object identifies that
allocated, such as Binding label/SID. A PCC would set this bit to the allocation is for binding label/SID. A PCC would set this bit
1 and include a TE-PATH-BINDING TLV in the LSP object to request to 1 and include a TE-PATH-BINDING TLV in the LSP object to
for allocation of Binding label/SID by the PCE in the PCEP request for allocation of binding label/SID by the PCE in the PCEP
message. A PCE would also set this bit to 1 and include a TE- message. A PCE would also set this bit to 1 and include a TE-
PATH-BINDING TLV to indicate that the Binding label/SID is PATH-BINDING TLV to indicate that the binding label/SID is
allocated by PCE and encoded in the PCEP message towards PCC. allocated by PCE and encoded in the PCEP message towards PCC.
Further, a PCE would set this bit to 0 and include a TE-PATH- Further, a PCE would set this bit to 0 and include a TE-PATH-
BINDING TLV in the LSP object to indicate that the Binding label/ BINDING TLV in the LSP object to indicate that the binding label/
SID should be allocated by the PCC as described in Section 4. SID should be allocated by the PCC as described in Section 5.
Note that, Note that -
o a PCE could allocate the binding label/SID on its own accord for a o A PCE could allocate the binding label/SID on its own accord for a
PCE-initiated or delegated LSP, and inform the PCC in the PCE-initiated or 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.
o to let the PCC allocates the binding label/SID, a PCE could set o To let the PCC allocates the binding label/SID, a PCE could set
P=0 and empty TE-PATH-BINDING TLV ( i.e., no binding value is P=0 and include an empty TE-PATH-BINDING TLV ( i.e., no binding
specified) in the LSP object in PCInitiate/PCUpd message. value is specified) in the LSP object in PCInitiate/PCUpd message.
o a PCC could request that the PCE allocate the binding label/SID by o A PCC could request that the PCE allocate the binding label/SID by
setting P=1, D=1, and empty TE-PATH-BINDING TLV in PCRpt message. setting P=1, D=1, and including an empty TE-PATH-BINDING TLV in
The PCE would allocate it and respond to the PCC with PCUpd PCRpt message. The PCE would allocate it and respond to the PCC
message including the allocated binding label/SID in the TE-PATH- with PCUpd message including the allocated binding label/SID in
BINDING TLV and P=1, D=1 in the LSP object. the TE-PATH-BINDING TLV and P=1, D=1 in the LSP object.
o if both peers have not exchanged the PCECC capabilities as per o If both peers have not exchanged the PCECC capabilities as per
[I-D.ietf-pce-pcep-extension-for-pce-controller] and it receives [I-D.ietf-pce-pcep-extension-for-pce-controller] and a PCEP peer
P=1 in the LSP object, it needs to act as per receives P=1 in the LSP object, it needs to act as per
[I-D.ietf-pce-pcep-extension-for-pce-controller]: [I-D.ietf-pce-pcep-extension-for-pce-controller]:
* Send a PCErr message with Error-Type=19 (Invalid Operation) and * Send a PCErr message with Error-Type=19 (Invalid Operation) and
Error-Value=TBD (Attempted PCECC operations when PCECC Error-Value=16 (Attempted PCECC operations when PCECC
capability was not advertised) capability was not advertised)
* Terminate the PCEP session * Terminate the PCEP session
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 scope of set on both PCEP peers. The exact mechanism is out of scope of
[I-D.ietf-pce-pcep-extension-for-pce-controller] or this document. [I-D.ietf-pce-pcep-extension-for-pce-controller] or this document.
Note that the specific BSID could be from the PCE-controlled or the Note that the specific BSID could be from the PCE-controlled or the
PCC-controlled label space. PCE would directly allocate the label PCC-controlled label space. The PCE can directly allocate the label
from the PCE-controlled label space using P=1 as described above, from the PCE-controlled label space using P=1 as described above,
whereas PCE would request for the allocation of a specific BSID from whereas the PCE can request for the allocation of a specific BSID
the PCC-controlled label space with P=0 as described in Section 4. from the PCC-controlled label space with P=0 as described in
Section 5.
8. Implementation Status 9. Implementation Status
[Note to the RFC Editor - remove this section before publication, as [Note to the RFC Editor - remove this section before publication, as
well as remove the reference to RFC 7942.] well as remove the reference to RFC 7942.]
This section records the status of known implementations of the This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in [RFC7942]. Internet-Draft, and is based on a proposal described in [RFC7942].
The description of implementations in this section is intended to The description of implementations in this section is intended to
assist the IETF in its decision processes in progressing drafts to assist the IETF in its decision processes in progressing drafts to
RFCs. Please note that the listing of any individual implementation RFCs. Please note that the listing of any individual implementation
skipping to change at page 12, line 47 skipping to change at page 13, line 30
features. Readers are advised to note that other implementations may features. Readers are advised to note that other implementations may
exist. exist.
According to [RFC7942], "this will allow reviewers and working groups According to [RFC7942], "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature. and feedback that have made the implemented protocols more mature.
It is up to the individual working groups to use this information as It is up to the individual working groups to use this information as
they see fit". they see fit".
8.1. Huawei 9.1. Huawei
o Organization: Huawei o Organization: Huawei
o Implementation: Huawei's Router and Controller o Implementation: Huawei's Router and Controller
o Description: An experimental code-point is used and plan to o Description: An experimental code-point is used and plan to
request early code-point allocation from IANA after WG adoption. request early code-point allocation from IANA after WG adoption.
o Maturity Level: Production o Maturity Level: Production
o Coverage: Full o Coverage: Full
o Contact: chengli13@huawei.com o Contact: chengli13@huawei.com
8.2. Cisco 9.2. Cisco
o Organization: Cisco Systems o Organization: Cisco Systems
o Implementation: Head-end and controller. o Implementation: Head-end and controller.
o Description: An experimental code-point is currently used. o Description: An experimental code-point is currently used.
o Maturity Level: Production o Maturity Level: Production
o Coverage: Full o Coverage: Full
o Contact: mkoldych@cisco.com o Contact: mkoldych@cisco.com
9. Security Considerations 10. Security Considerations
The security considerations described in [RFC5440], [RFC8231], The security considerations described in [RFC5440], [RFC8231],
[RFC8281] and [RFC8664] are applicable to this specification. No [RFC8281] and [RFC8664] are applicable to this specification. No
additional security measure is required. additional security measure is required.
As described [RFC8664], SR allows a network controller to instantiate As described [RFC8664], SR allows a network controller to instantiate
and control paths in the network. A rouge PCE can manipulate binding and control paths in the network. A rogue PCE can manipulate binding
SID allocations to move traffic around for some other LSPs that uses SID allocations to move traffic around for some other LSP that uses
BSID in its SR-ERO. BSID in its SR-ERO.
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 BCP195 [RFC7525] (unless explicitly set
aside in [RFC8253]). aside in [RFC8253]).
10. Manageability Considerations 11. 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.
10.1. Control of Function and Policy 11.1. 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 based on which PCC needs to allocates the binding label/SID. policy based on which PCC needs to allocates the binding label/SID.
10.2. Information and Data Models 11.2. Information and Data Models
The PCEP YANG module [I-D.ietf-pce-pcep-yang] could be extended to The PCEP YANG module [I-D.ietf-pce-pcep-yang] could be extended to
include policy configuration for binding label/SID allocation. include policy configuration for binding label/SID allocation.
10.3. Liveness Detection and Monitoring 11.3. Liveness Detection and Monitoring
Mechanisms defined in this document do not imply any new liveness 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].
10.4. Verify Correct Operations 11.4. Verify Correct Operations
Mechanisms defined in this document do not imply any new operation Mechanisms defined in this document do not imply any new operation
verification requirements in addition to those already listed in verification requirements in addition to those already listed in
[RFC5440], [RFC8231], and [RFC8664]. [RFC5440], [RFC8231], and [RFC8664].
10.5. Requirements On Other Protocols 11.5. Requirements On Other Protocols
Mechanisms defined in this document do not imply any new requirements Mechanisms defined in this document do not imply any new requirements
on other protocols. on other protocols.
10.6. Impact On Network Operations 11.6. Impact On Network Operations
Mechanisms defined in [RFC5440], [RFC8231], and [RFC8664] also apply Mechanisms defined in [RFC5440], [RFC8231], and [RFC8664] also apply
to PCEP extensions defined in this document. Further, the mechanism to PCEP extensions defined in this document. Further, the mechanism
described in this document can help the operator to request control described in this document can help the operator to request control
of the LSPs at a particular PCE. of the LSPs at a particular PCE.
11. IANA Considerations 12. IANA Considerations
IANA maintains the "Path Computation Element Protocol (PCEP) Numbers" IANA maintains the "Path Computation Element Protocol (PCEP) Numbers"
registry. This document requests IANA actions to allocate code registry. This document requests IANA actions to allocate code
points for the protocol elements defined in this document. points for the protocol elements defined in this document.
11.1. PCEP TLV Type Indicators 12.1. PCEP TLV Type Indicators
This document defines a new PCEP TLV; IANA is requested to make the This document defines a new PCEP TLV; IANA is requested to confirm
following allocations from the "PCEP TLV Type Indicators" subregistry the following early allocations from the "PCEP TLV Type Indicators"
of the PCEP Numbers registry, as follows: subregistry of the PCEP Numbers registry, as follows:
Value Description Reference Value Description Reference
TBD1 TE-PATH-BINDING This document 55 TE-PATH-BINDING This document
11.1.1. TE-PATH-BINDING TLV 12.1.1. TE-PATH-BINDING TLV
IANA is requested to create a new subregistry "TE-PATH-BINDING TLV BT IANA is requested to create a new subregistry "TE-PATH-BINDING TLV BT
field" to manage the value of the Binding Type field in the TE-PATH- field" to manage the value of the Binding Type field in the TE-PATH-
BINDING TLV. Initial values for the subregistry are given below. BINDING TLV. Initial values for the subregistry are given below.
New values are assigned by Standards Action [RFC8126]. New values are assigned by Standards Action [RFC8126].
Value Description Reference Value Description Reference
0 MPLS Label This document 0 MPLS Label This document
1 MPLS Label Stack This document 1 MPLS Label Stack This document
Entry Entry
2 SRv6 SID This document 2 SRv6 SID This document
3 SRv6 SID with This document 3 SRv6 SID with This document
Behavior and Behavior and
Structure Structure
4-255 Unassigned This document
IANA is requested to create a new subregistry "TE-PATH-BINDING TLV IANA is requested to create a new subregistry "TE-PATH-BINDING TLV
Flag field" to manage the Flag field in the TE-PATH-BINDING TLV. New Flag field" to manage the Flag field in the TE-PATH-BINDING TLV. New
values are to be assigned by Standards Action [RFC8126]. Each bit values are to be assigned by Standards Action [RFC8126]. Each bit
should be tracked with the following qualities: should be tracked with the following qualities:
o Bit number (count from 0 as the most significant bit) o Bit number (count from 0 as the most significant bit)
o Description o Description
o Reference o Reference
Bit Description Reference Bit Description Reference
7 Specified-BSID-Only This document 0 R (Removal) This document
Flag (S-Flag) 1-7 Unassigned This document
6 Drop Upon Invalid This document
Flag (I-Flag)
11.2. LSP Object 12.2. LSP Object
IANA is requested to allocate new code-point in the "LSP Object Flag IANA is requested to confirm the early allocation for a new code-
Field" sub-registry for the new P flag as follows: point in the "LSP Object Flag Field" sub-registry for the new P flag
as follows:
Bit Description Reference Bit Description Reference
TBD6 PCE-allocated binding This document 0 PCE-allocated binding This document
label/SID label/SID
11.3. PCEP Error Type and Value 12.3. PCEP Error Type and Value
This document defines a new Error-type and Error-Values for the PCErr This document defines a new Error-type and Error-Values for the PCErr
message. IANA is requested to allocate new error-type and error- message. IANA is requested to allocate new error-type and error-
values within the "PCEP-ERROR Object Error Types and Values" values within the "PCEP-ERROR Object Error Types and Values"
subregistry of the PCEP Numbers registry, as follows: subregistry of the PCEP Numbers registry, as follows:
Error-Type Meaning Error-value Reference Error-Type Meaning Error-value Reference
TBD2 Binding label/SID This TBD2 Binding label/SID This
failure document failure document
TBD3: Invalid SID This TBD3: Invalid SID This
document document
TBD4: Unable to allocate the This TBD4: Unable to allocate the This
specified label/SID document specified binding value document
TBD5: Unable to allocate This TBD5: Unable to allocate a This
label/SID document new binding label/SID document
12. Acknowledgements 13. Acknowledgements
We like to thank Milos Fabian, Mrinmoy Das, and Andrew Stone for We like to thank Milos Fabian, Mrinmoy Das, Andrew Stone, Tom Petch,
their valuable comments. Aijun Wang, Olivier Dugeon, and Adrian Farrel for their valuable
comments.
13. References 14. References
13.1. Normative References 14.1. Normative References
[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.,
Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001,
<https://www.rfc-editor.org/info/rfc3032>.
[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>.
skipping to change at page 17, line 48 skipping to change at page 18, line 48
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 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>. <https://www.rfc-editor.org/info/rfc8126>.
[I-D.ietf-spring-srv6-network-programming] [RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
Filsfils, C., Camarillo, P., Leddy, J., Voyer, D., D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
Matsushima, S., and Z. Li, "SRv6 Network Programming", (SRv6) Network Programming", RFC 8986,
draft-ietf-spring-srv6-network-programming-28 (work in DOI 10.17487/RFC8986, February 2021,
progress), December 2020. <https://www.rfc-editor.org/info/rfc8986>.
[I-D.ietf-pce-pcep-extension-for-pce-controller] [I-D.ietf-pce-pcep-extension-for-pce-controller]
Li, Z., Peng, S., Negi, M., Zhao, Q., and C. Zhou, "PCEP Li, Z., Peng, S., Negi, M., Zhao, Q., and C. Zhou, "PCEP
Procedures and Protocol Extensions for Using PCE as a Procedures and Protocol Extensions for Using PCE as a
Central Controller (PCECC) of LSPs", draft-ietf-pce-pcep- Central Controller (PCECC) of LSPs", draft-ietf-pce-pcep-
extension-for-pce-controller-10 (work in progress), extension-for-pce-controller-10 (work in progress),
January 2021. January 2021.
13.2. Informative References 14.2. Informative References
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655, 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,
skipping to change at page 19, line 5 skipping to change at page 19, line 43
P. Mattes, "Segment Routing Policy Architecture", draft- P. Mattes, "Segment Routing Policy Architecture", draft-
ietf-spring-segment-routing-policy-09 (work in progress), ietf-spring-segment-routing-policy-09 (work in progress),
November 2020. November 2020.
[I-D.ietf-pce-pcep-yang] [I-D.ietf-pce-pcep-yang]
Dhody, D., Hardwick, J., Beeram, V., and J. Tantsura, "A Dhody, D., Hardwick, J., Beeram, V., and J. Tantsura, "A
YANG Data Model for Path Computation Element YANG Data Model for Path Computation Element
Communications Protocol (PCEP)", draft-ietf-pce-pcep- Communications Protocol (PCEP)", draft-ietf-pce-pcep-
yang-15 (work in progress), October 2020. yang-15 (work in progress), October 2020.
[I-D.ietf-pce-segment-routing-ipv6]
Li, C., Negi, M., Sivabalan, S., Koldychev, M.,
Kaladharan, P., and Y. Zhu, "PCEP Extensions for Segment
Routing leveraging the IPv6 data plane", draft-ietf-pce-
segment-routing-ipv6-08 (work in progress), November 2020.
Appendix A. Contributor Addresses Appendix A. Contributor Addresses
Jonathan Hardwick Jonathan Hardwick
Metaswitch Networks Metaswitch Networks
100 Church Street 33 Genotin Road
Enfield, Middlesex Enfield
UK United Kingdom
EMail: Jonathan.Hardwick@metaswitch.com EMail: Jonathan.Hardwick@metaswitch.com
Dhruv Dhody Dhruv Dhody
Huawei Technologies Huawei Technologies
Divyashree Techno Park, Whitefield Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560066 Bangalore, Karnataka 560066
India India
EMail: dhruv.ietf@gmail.com EMail: dhruv.ietf@gmail.com
skipping to change at page 20, line 13 skipping to change at page 21, line 13
EMail: msiva282@gmail.com EMail: msiva282@gmail.com
Clarence Filsfils Clarence Filsfils
Cisco Systems, Inc. Cisco Systems, Inc.
Pegasus Parc Pegasus Parc
De kleetlaan 6a, DIEGEM BRABANT 1831 De kleetlaan 6a, DIEGEM BRABANT 1831
BELGIUM BELGIUM
EMail: cfilsfil@cisco.com EMail: cfilsfil@cisco.com
Jeff Tantsura Jeff Tantsura
Apstra, Inc. Juniper Networks
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 Cheng Li
Huawei Technologies Huawei Technologies
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