Internet DRAFT - draft-ietf-pce-segment-routing-ipv6
draft-ietf-pce-segment-routing-ipv6
PCE Working Group C. Li
Internet-Draft Huawei Technologies
Intended status: Standards Track P. Kaladharan
Expires: 18 August 2024 RtBrick Inc
S. Sivabalan
Ciena Corporation
M. Koldychev
Cisco Systems, Inc.
Y. Zhu
China Telecom
15 February 2024
Path Computation Element Communication Protocol (PCEP) Extensions for
Segment Routing leveraging the IPv6 dataplane
draft-ietf-pce-segment-routing-ipv6-22
Abstract
Segment Routing (SR) can be used to steer packets through an IPv6 or
MPLS network using the source routing paradigm. SR enables any head-
end node to select any path without relying on a hop-by-hop signaling
technique (e.g., LDP or RSVP-TE).
A Segment Routed Path can be derived from a variety of mechanisms,
including an IGP Shortest Path Tree (SPT), explicit configuration, or
a Path Computation Element(PCE).
Since SR can be applied to both MPLS and IPv6 forwarding planes, a
PCE should be able to compute an SR Path for both MPLS and IPv6
forwarding planes. The PCEP extension and mechanisms to support SR-
MPLS have been defined. This document describes the extensions
required for SR support for the IPv6 data plane in the Path
Computation Element communication Protocol (PCEP).
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on 18 August 2024.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
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Please review these documents carefully, as they describe your rights
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Overview of PCEP Operation in SRv6 Networks . . . . . . . . . 5
3.1. Operation Overview . . . . . . . . . . . . . . . . . . . 6
3.2. SRv6-Specific PCEP Message Extensions . . . . . . . . . . 6
4. Object Formats . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. The OPEN Object . . . . . . . . . . . . . . . . . . . . . 6
4.1.1. The SRv6 PCE Capability sub-TLV . . . . . . . . . . . 6
4.2. The RP/SRP Object . . . . . . . . . . . . . . . . . . . . 8
4.3. ERO . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.3.1. SRv6-ERO Subobject . . . . . . . . . . . . . . . . . 8
4.3.1.1. SID Structure . . . . . . . . . . . . . . . . . . 11
4.3.1.2. Order of the Optional fields . . . . . . . . . . 12
4.4. RRO . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.4.1. SRv6-RRO Subobject . . . . . . . . . . . . . . . . . 13
5. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1. Exchanging the SRv6 Capability . . . . . . . . . . . . . 14
5.2. ERO Processing . . . . . . . . . . . . . . . . . . . . . 15
5.2.1. SRv6 ERO Validation . . . . . . . . . . . . . . . . . 15
5.2.2. Interpreting the SRv6-ERO . . . . . . . . . . . . . . 16
5.3. RRO Processing . . . . . . . . . . . . . . . . . . . . . 16
6. Security Considerations . . . . . . . . . . . . . . . . . . . 17
7. Manageability Considerations . . . . . . . . . . . . . . . . 17
7.1. Control of Function and Policy . . . . . . . . . . . . . 17
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7.2. Information and Data Models . . . . . . . . . . . . . . . 18
7.3. Liveness Detection and Monitoring . . . . . . . . . . . . 18
7.4. Verify Correct Operations . . . . . . . . . . . . . . . . 18
7.5. Requirements On Other Protocols . . . . . . . . . . . . . 18
7.6. Impact On Network Operations . . . . . . . . . . . . . . 18
8. Implementation Status . . . . . . . . . . . . . . . . . . . . 18
8.1. Cisco's Commercial Delivery . . . . . . . . . . . . . . . 19
8.2. Huawei's Commercial Delivery . . . . . . . . . . . . . . 19
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
9.1. PCEP ERO and RRO subobjects . . . . . . . . . . . . . . . 19
9.2. New SRv6-ERO NAI Type Registry . . . . . . . . . . . . . 20
9.3. New SRv6-ERO Flag Registry . . . . . . . . . . . . . . . 20
9.4. LSP-ERROR-CODE TLV . . . . . . . . . . . . . . . . . . . 21
9.5. PATH-SETUP-TYPE-CAPABILITY Sub-TLV Type Indicators . . . 21
9.6. SRv6 PCE Capability Flags . . . . . . . . . . . . . . . . 21
9.7. New Path Setup Type . . . . . . . . . . . . . . . . . . . 22
9.8. ERROR Objects . . . . . . . . . . . . . . . . . . . . . . 22
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 23
10.1. Normative References . . . . . . . . . . . . . . . . . . 23
10.2. Informative References . . . . . . . . . . . . . . . . . 24
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 26
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27
1. Introduction
As defined in [RFC8402], Segment Routing (SR) architecture allows the
source node to steer a packet through a path indicated by an ordered
list of instructions, called segments. A segment can represent any
instruction, topological or service-based, and it can have a semantic
local to an SR node or global within an SR domain.
When the SR architecture is applied to the MPLS forwarding plane, it
is called SR-MPLS. When the SR architecture is applied to the IPv6
data plane, is is called SRv6 (Segment Routing over IPv6 data plane)
[RFC8754].
An SR path can be derived from an IGP Shortest Path Tree (SPT), but
SR-TE (Segment Routing Traffic Engineering) paths might not follow
IGP SPT. Such paths may be chosen by a suitable network planning
tool, or a PCE and provisioned on the ingress node.
[RFC5440] describes Path Computation Element communication Protocol
(PCEP) for communication between a Path Computation Client (PCC) and
a Path Computation Element (PCE) or between a pair of PCEs. A PCE or
a PCC operating as a PCE (in hierarchical PCE environment) computes
paths for MPLS Traffic Engineering LSPs (MPLS-TE LSPs) based on
various constraints and optimization criteria.
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[RFC8231] specifies extensions to PCEP that allow a stateful PCE to
compute and recommend network paths in compliance with [RFC4657] and
defines objects and TLVs for MPLS-TE LSPs. Stateful PCEP extensions
provide synchronization of LSP state between a PCC and a PCE or
between a pair of PCEs, delegation of LSP control, reporting of LSP
state from a PCC to a PCE, controlling the setup and path routing of
an LSP from a PCE to a PCC. Stateful PCEP extensions are intended
for an operational model in which LSPs are configured on the PCC, and
control over them is delegated to the PCE.
A mechanism to dynamically initiate LSPs on a PCC based on the
requests from a stateful PCE or a controller using stateful PCE is
specified in [RFC8281]. As per [RFC8664], it is possible to use a
stateful PCE for computing one or more SR-TE paths taking into
account various constraints and objective functions. Once a path is
chosen, the stateful PCE can initiate an SR-TE path on a PCC using
PCEP extensions specified in [RFC8281] and the SR-specific PCEP
extensions specified in [RFC8664]. [RFC8664] specifies PCEP
extensions for supporting a SR-TE LSP for the MPLS data plane. This
document extends [RFC8664] to support SR for the IPv6 data plane.
Additionally, using procedures described in this document, a PCC can
request an SRv6 path from either a stateful or stateless PCE. This
specification relies on the PATH-SETUP-TYPE TLV and procedures
specified in [RFC8408].
This specification provides a mechanism for a network controller
(acting as a PCE) to instantiate candidate paths for an SR Policy
onto a head-end node (acting as a PCC) using PCEP. For more
information on the SR Policy Architecture, see [RFC9256] which is
applicable to both SR-MPLS and SRv6.
1.1. 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.
2. Terminology
This document uses the following terms defined in [RFC5440]: PCC,
PCE, PCEP, PCEP Peer.
This document uses the following terms defined in [RFC8051]: Stateful
PCE, Delegation.
Further, following terms are used in the document,
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MSD: Maximum SID Depth.
PST: Path Setup Type.
SR: Segment Routing.
SID: Segment Identifier.
SRv6: Segment Routing over IPv6 data plane.
SRH: IPv6 Segment Routing Header.
SRv6 Path: IPv6 Segment List (List of IPv6 SIDs representing a path
in IPv6 SR domain in the context of this document)
Further, note that the term LSP used in the PCEP specifications,
would be equivalent to an SRv6 Path (represented as a list of SRv6
segments) in the context of supporting SRv6 in PCEP.
3. Overview of PCEP Operation in SRv6 Networks
Basic operations for PCEP speakers are as per [RFC8664]. SRv6 Paths
computed by a PCE can be represented as an ordered list of SRv6
segments.
[RFC8664] defined a new Explicit Route Object (ERO) subobject denoted
by "SR-ERO subobject" capable of carrying a SID as well as the
identity of the node/adjacency represented by the SID for SR-MPLS.
SR-capable PCEP speakers can generate and/or process such an ERO
subobject. An ERO containing SR-ERO subobjects can be included in
the PCEP Path Computation Reply (PCRep) message defined in [RFC5440],
the PCEP LSP Initiate Request message (PCInitiate) defined in
[RFC8281], as well as in the PCEP LSP Update Request (PCUpd) and PCEP
LSP State Report (PCRpt) messages defined in [RFC8231]. [RFC8664]
also defines a new Reported Route Object(RRO) called SR-RRO to
represents the SID list that was applied by the PCC, that is, the
actual path taken by the LSP in SR-MPLS network.
This document defines new subobjects "SRv6-ERO" and "SRv6-RRO" in the
ERO and the RRO respectively to carry the SRv6 SID. SRv6-capable
PCEP speakers MUST be able to generate and/or process these
subobjects.
When a PCEP session between a PCC and a PCE is established, both PCEP
speakers exchange their capabilities to indicate their ability to
support SRv6 specific functionality as described in Section 4.1.1.
In summary, this document,
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* Defines a new PCEP capability for SRv6.
* Defines a new subobject SRv6-ERO in ERO.
* Defines a new subobject SRv6-RRO in RRO.
* Defines a new path setup type (PST) [RFC8408] carried in the PATH-
SETUP-TYPE TLV and the PATH-SETUP-TYPE-CAPABILITY TLV.
3.1. Operation Overview
In SR networks, an SR source node encodes all packets being steered
onto an SR path with a list of segments.
For the use of an IPv6 control plane but an MPLS data plane,
mechanism remains the same as specified in [RFC8664].
This document describes the extension to support SRv6 in PCEP. A PCC
or PCE indicates its ability to support SRv6 during the PCEP session
Initialization Phase via a new SRv6-PCE-CAPABILITY sub-TLV (see
details in Section 4.1.1).
3.2. SRv6-Specific PCEP Message Extensions
As defined in [RFC5440], a PCEP message consists of a common header
followed by a variable length body made up of mandatory and/or
optional objects. This document does not require any changes in the
format of PCReq and PCRep messages specified in [RFC5440], PCInitiate
message specified in [RFC8281], and PCRpt and PCUpd messages
specified in [RFC8231]. However, PCEP messages pertaining to SRv6
MUST include PATH-SETUP-TYPE TLV in the RP (Request Parameters) or
SRP (Stateful PCE Request Parameters) object to clearly identify that
SRv6 is intended.
4. Object Formats
4.1. The OPEN Object
4.1.1. The SRv6 PCE Capability sub-TLV
This document defines a new Path Setup Type (PST) [RFC8408] for SRv6,
as follows.
* PST = 3 : Path is setup using SRv6.
A PCEP speaker indicates its support of the function described in
this document by sending a PATH-SETUP-TYPE-CAPABILITY TLV in the OPEN
object with this new PST "3" included in the PST list.
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This document also defines the SRv6-PCE-CAPABILITY sub-TLV. PCEP
speakers use this sub-TLV to exchange information about their SRv6
capability. If a PCEP speaker includes PST=3 in the PST List of the
PATH-SETUP-TYPE-CAPABILITY TLV then it MUST also include the SRv6-
PCE-CAPABILITY sub-TLV inside the PATH-SETUP-TYPE-CAPABILITY TLV.
For further error handling, please see Section 5.
The format of the SRv6-PCE-CAPABILITY sub-TLV is shown in the
following figure.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=27 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Flags |N| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MSD-Type | MSD-Value | MSD-Type | MSD-Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// ... //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MSD-Type | MSD-Value | Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: SRv6-PCE-CAPABILITY sub-TLV format
The code point for the TLV type is 27 and the format is compliant
with the PCEP TLV format defined in [RFC5440]. That is, the sub-TLV
is composed of 2 octets for the type, 2 octets specifying the length,
and a Value field. The Type field when set to 27 identifies the
SRv6-PCE-CAPABILITY sub-TLV and the presence of the sub-TLV indicates
the support for the SRv6 paths in PCEP. The Length field defines the
length of the value portion in octets. The TLV is padded to 4-octet
alignment, and padding is not included in the Length field. The
(MSD-Type,MSD-Value) pairs are OPTIONAL. The number of (MSD-
Type,MSD-Value) pairs can be determined from the Length field of the
TLV.
The value comprises of -
Reserved: 2 octet, this field MUST be set to 0 on transmission,
and ignored on receipt.
Flags: 2 octet, one bit is currently assigned in this document.
Section 9.6
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- N bit: A PCC sets this flag bit to 1 to indicate that it is
capable of resolving a Node or Adjacency Identifier (NAI) to an
SRv6-SID.
- Unassigned bits MUST be set to 0 on transmission and ignored on
receipt
A pair of (MSD-Type, MSD-Value): Where MSD-Type (1 octet) is as
per the IGP MSD Type registry created by [RFC8491] and populated
with SRv6 MSD types as per [RFC9352]; MSD-Value (1 octet) is as
per [RFC8491].
The SRv6 MSD information advertised via SRv6-PCE-Capability sub-TLV
conveys the SRv6 capabilities of the PCEP speaker alone. However,
when it comes to the computation of an SR Policy for the SRv6
dataplane, the SRv6 MSD capabilities of all the intermediate SRv6
Endpoint node as well as the tailend node also need to be considered
to ensure those midpoints are able to correctly process their
segments and for the tailend to dispose of the SRv6 encapsulation.
The SRv6 MSD capabilities of other nodes might be learned as part of
the topology information via BGP-LS[RFC9514] or via PCEP if the PCE
also happens to have PCEP sessions to those nodes.
It is recommended that the SRv6 MSD information be not included in
the SRv6-PCE-Capability sub-TLV in deployments where the PCE is able
to obtain this via IGP/BGP-LS as part of the topology information.
4.2. The RP/SRP Object
This document defines a new Path Setup Type (PST=3) for SRv6. In
order to indicate that the path is for SRv6, any RP or SRP object
MUST include the PATH-SETUP-TYPE TLV as specified in [RFC8408], where
PST is set to 3.
4.3. ERO
In order to support SRv6, a new "SRv6-ERO" subobject is defined for
inclusion in the ERO.
4.3.1. SRv6-ERO Subobject
An SRv6-ERO subobject is formatted as shown in the following figure.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Type=40 | Length | NT | Flags |V|T|F|S|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Endpoint Behavior |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| SRv6 SID (conditional) |
| (128-bit) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// NAI (variable, conditional) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| SID Structure (conditional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: SRv6-ERO Subobject Format
The fields in the SRv6-ERO subobject are as follows:
The 'L' Flag: Indicates whether the subobject represents a loose-hop
(see [RFC3209]). If this flag is set to zero, a PCC MUST NOT
overwrite the SID value present in the SRv6-ERO subobject.
Otherwise, a PCC MAY expand or replace one or more SID values in the
received SRv6-ERO based on its local policy.
Type: indicates the content of the subobject, i.e. when the field is
set to 40, the suboject is an SRv6-ERO subobject representing an SRv6
SID.
Length: Contains the total length of the subobject in octets. The
Length MUST be at least 24, and MUST be a multiple of 4. An SRv6-ERO
subobject MUST contain at least one of an SRv6-SID or an NAI. The S
and F bit in the Flags field indicates whether the SRv6-SID or NAI
fields are absent.
NAI Type (NT): Indicates the type and format of the NAI contained in
the object body, if any is present. If the F bit is set to one (see
below) then the NT field has no meaning and MUST be ignored by the
receiver. This document creates a new PCEP SRv6-ERO NAI Types
registry in IANA add allocates the following values.
If NT value is 0, the NAI MUST NOT be included.
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When NT value is 2, the NAI is as per the 'IPv6 Node ID' format
defined in [RFC8664], which specifies an IPv6 address. This is
used to identify the owner of the SRv6 Identifier. This is
optional, as the LOC (the locator portion) of the SRv6 SID serves
a similar purpose (when present).
When NT value is 4, the NAI is as per the 'IPv6 Adjacency' format
defined in [RFC8664], which specify a pair of IPv6 addresses.
This is used to identify the IPv6 Adjacency and used with the SRv6
Adj-SID.
When NT value is 6, the NAI is as per the 'link-local IPv6
addresses' format defined in [RFC8664], which specify a pair of
(global IPv6 address, interface ID) tuples. It is used to
identify the IPv6 Adjacency and used with the SRv6 Adj-SID.
Flags: Used to carry additional information pertaining to the
SRv6-SID. This document defines the following flag bits. The other
bits MUST be set to zero by the sender and MUST be ignored by the
receiver.
* S: When this bit is set to 1, the SRv6-SID value in the subobject
body is absent. In this case, the PCC is responsible for choosing
the SRv6-SID value, e.g., by looking up in the SR-DB using the NAI
which, in this case, MUST be present in the subobject. If the S
bit is set to 1 then F bit MUST be set to zero.
* F: When this bit is set to 1, the NAI value in the subobject body
is absent. The F bit MUST be set to 1 if NT=0, and otherwise MUST
be set to zero. The S and F bits MUST NOT both be set to 1.
* T: When this bit is set to 1, the SID Structure value in the
subobject body is present. The T bit MUST be set to 0 when S bit
is set to 1. If the T bit is set when the S bit is set, the T bit
MUST be ignored. Thus, the T bit indicates the presence of an
optional 8-byte SID Structure when SRv6 SID is included. The SID
Structure is defined in Section 4.3.1.1.
* V: The "SID verification" bit usage is as per Section 5.1 of
[RFC9256]. If a PCC "Verification fails" for a SID, it MUST
report this error by including the LSP-ERROR-CODE TLV with LSP
error-value "SID Verification fails" in the LSP object in the
PCRpt message to the PCE.
Reserved: MUST be set to zero while sending and ignored on receipt.
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Endpoint Behavior: A 16-bit field representing the behavior
associated with the SRv6 SIDs. This information is optional, but it
is recommended to signal it always if possible. It could be used for
maintainability and diagnostic purpose. If behavior is not known,
value '0xFFFF' defined in the registry "SRv6 Endpoint Behaviors" is
used [RFC8986].
SRv6 SID: SRv6 Identifier is an 128-bit value representing the SRv6
segment.
NAI: The NAI associated with the SRv6-SID. The NAI's format depends
on the value in the NT field, and is described in [RFC8664].
At least one SRv6-SID or the NAI MUST be included in the SRv6-ERO
subobject, and both MAY be included.
4.3.1.1. SID Structure
The SID Structure is an optional part of the SR-ERO subobject, as
described in Section 4.3.1.
[RFC8986] defines an SRv6 SID as consisting of LOC:FUNCT:ARG, 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 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 operator) and N is
the identifier of the parent node instantiating the SID called
locator node.
It is formatted as shown in the following figure.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LB Length | LN Length | Fun. Length | Arg. Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: SID Structure Format
where:
LB Length: 1 octet. SRv6 SID Locator Block length in bits.
LN Length: 1 octet. SRv6 SID Locator Node length in bits.
Fun. Length: 1 octet. SRv6 SID Function length in bits.
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Arg. Length: 1 octet. SRv6 SID Arguments length in bits.
The sum of all four sizes in the SID Structure must be lower or equal
to 128 bits. If the sum of all four sizes advertised in the SID
Structure is larger than 128 bits, the corresponding SRv6 SID MUST be
considered invalid and a PCErr message with Error-Type = 10
("Reception of an invalid object") and Error-Value = 37 ("Invalid
SRv6 SID Structure") is returned.
Reserved: MUST be set to zero while sending and ignored on receipt.
Flags: Currently no flags are defined. Unassigned bits must be set
to zero while sending and ignored on receipt.
The SRv6 SID Structure provides the detailed encoding information of
an SRv6 SID, which is useful in the use cases that require to know
the SRv6 SID structure. When a PCEP speaker receives the SRv6 SID
and its structure information, the SRv6 SID can be parsed based on
the SRv6 SID Structure and/or possible local policies. The SRv6 SID
Structure could be used by the PCE for ease of operations and
monitoring. For example, this information could be used for
validation of SRv6 SIDs being instantiated in the network and checked
for conformance to the SRv6 SID allocation scheme chosen by the
operator as described in Section 3.2 of [RFC8986]. In the future,
PCE might also be utilized to verify and automate the security of the
SRv6 domain by provisioning filtering rules at the domain boundaries
as described in Section 5 of [RFC8754]. The details of these
potential applications are outside the scope of this document.
4.3.1.2. Order of the Optional fields
The optional elements in the SRv6-ERO subobject i.e. SRv6 SID, NAI
and the SID Structure MUST be encoded in the order as depicted in
Figure 2. The presence of each of them is indicated by the
respective flags i.e. S flag, F flag and T flag.
In order to ensure future compatibility, any optional elements added
to the SRv6-ERO subobject in the future must specify their order and
request the Internet Assigned Numbers Authority (IANA) to allocate a
flag to indicate their presence from the subregistry created in
Section 9.3.
4.4. RRO
In order to support SRv6, a new "SRv6-RRO" subobject is defined for
inclusion in the RRO.
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4.4.1. SRv6-RRO Subobject
A PCC reports an SRv6 path to a PCE by sending a PCRpt message, per
[RFC8231]. The RRO on this message represents the SID list that was
applied by the PCC, that is, the actual path taken. The procedures
of [RFC8664] with respect to the RRO apply equally to this
specification without change.
An RRO contains one or more subobjects called "SRv6-RRO subobjects"
whose format is shown below.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=40 | Length | NT | Flags |V|T|F|S|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Endpoint Behavior |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| SRv6 SID(optional) |
| (128-bit) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// NAI (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| SID Structure (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: SRv6-RRO Subobject Format
The format of the SRv6-RRO subobject is the same as that of the
SRv6-ERO subobject, but without the L flag.
The V flag has no meaning in the SRv6-RRO and is ignored on receipt
at the PCE.
Ordering of SRv6-RRO subobjects by PCC in PCRpt message remains as
per [RFC8664].
The ordering of optional elements in the SRv6-RRO subobject is the
same as described in Section 4.3.1.2.
5. Procedures
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5.1. Exchanging the SRv6 Capability
A PCC indicates that it is capable of supporting the head-end
functions for SRv6 by including the SRv6-PCE-CAPABILITY sub-TLV in
the Open message that it sends to a PCE. A PCE indicates that it is
capable of computing SRv6 paths by including the SRv6-PCE-CAPABILITY
sub-TLV in the Open message that it sends to a PCC.
If a PCEP speaker receives a PATH-SETUP-TYPE-CAPABILITY TLV with a
PST list containing PST=3, but the SRv6-PCE-CAPABILITY sub-TLV is
absent, then the PCEP speaker MUST send a PCErr message with Error-
Type = 10 (Reception of an invalid object) and Error-Value = 34
(Missing PCE-SRv6-CAPABILITY sub-TLV) and MUST then close the PCEP
session. If a PCEP speaker receives a PATH-SETUP-TYPE-CAPABILITY TLV
with an SRv6-PCE-CAPABILITY sub-TLV, but the PST list does not
contain PST=3, then the PCEP speaker MUST ignore the SRv6-PCE-
CAPABILITY sub-TLV.
In case the MSD-Type in SRv6-PCE-CAPABILITY sub-TLV received by the
PCE does not correspond to one of the SRv6 MSD types, the PCE MUST
respond with a PCErr message (Error-Type = 1 "PCEP session
establishment failure" and Error-Value = 1 "reception of an invalid
Open message or a non Open message.").
Note that the MSD-Type, MSD-Value exchanged via the SRv6-PCE-
CAPABILITY sub-TLV indicates the SRv6 SID imposition limit for the
sender PCC node only. However, if a PCE learns these via alternate
mechanisms, e.g routing protocols [RFC9352], then it ignores the
values in the SRv6-PCE-CAPABILITY sub-TLV. Furthermore, whenever a
PCE learns any other SRv6 MSD types that may be defined in the future
via alternate mechanisms, it MUST use those values regardless of the
values exchanged in the SRv6-PCE-CAPABILITY sub-TLV.
During path computation, PCE must consider the MSD information of all
the nodes along the path instead of only the MSD information of the
ingress PCC since a packet may be dropped on any node in a forwarding
path because of MSD exceeding. The MSD capabilities of all SR nodes
along the path can be learned as part of the topology information via
IGP/BGP-LS or via PCEP if the PCE also happens to have PCEP sessions
to those nodes.
A PCE MUST NOT send SRv6 paths exceeding the SRv6 MSD capabilities of
the PCC. If a PCC needs to modify the SRv6 MSD value signaled via
the Open message, it MUST close the PCEP session and re-establish it
with the new value. If the PCC receives an SRv6 path that exceed its
SRv6 MSD capabilties, the PCC MUST send a PCErr message with Error-
Type = 10 (Reception of an invalid object) and Error-Value = 39
(Unsupported number of SRv6-ERO subobjects).
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The N flag and (MSD-Type,MSD-Value) pair inside the SRv6-PCE-
CAPABILITY sub-TLV are meaningful only in the Open message sent to a
PCE. As such,the flags MUST be set to zero and a (MSD-Type,MSD-
Value) pair MUST NOT be present in the SRv6-PCE-CAPABILITY sub-TLV in
an Open message sent to a PCC. Similarly, a PCC MUST ignore flags
and any (MSD-Type,MSD-Value) pair in a received Open message. If a
PCE receives multiple SRv6-PCE-CAPABILITY sub-TLVs in an Open
message, it processes only the first sub-TLV received.
5.2. ERO Processing
The processing of ERO remains unchanged in accordance with both
[RFC5440] and [RFC8664].
5.2.1. SRv6 ERO Validation
If a PCC does not support the SRv6 PCE Capability and thus cannot
recognize the SRv6-ERO or SRv6-RRO subobjects, it should respond
according to the rules for a malformed object as described in
[RFC5440].
On receiving an SRv6-ERO, a PCC MUST validate that the Length field,
the S bit, the F bit, the T bit, and the NT field are consistent, as
follows.
* If NT=0, the F bit MUST be 1, the S bit MUST be zero and the
Length MUST be 24.
* If NT=2, the F bit MUST be zero. If the S bit is 1, the Length
MUST be 24, otherwise the Length MUST be 40.
* If NT=4, the F bit MUST be zero. If the S bit is 1, the Length
MUST be 40, otherwise the Length MUST be 56.
* If NT=6, the F bit MUST be zero. If the S bit is 1, the Length
MUST be 48, otherwise the Length MUST be 64.
* If T bit is 1, then S bit MUST be zero.
If a PCC finds that the NT field, Length field, S bit, F bit, and T
bit are not consistent, it MUST consider the entire ERO invalid and
MUST send a PCErr message with Error-Type = 10 ("Reception of an
invalid object") and Error-Value = 11 ("Malformed object").
If a PCC does not recognize or support the value in the NT field, it
MUST consider the entire ERO invalid and send a PCErr message with
Error-Type = 10 ("Reception of an invalid object") and Error- value =
40 ("Unsupported NAI Type in the SRv6-ERO/SRv6-RRO subobject").
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If a PCC receives an SRv6-ERO subobject in which the S and F bits are
both set to 1 (that is, both the SID and NAI are absent), it MUST
consider the entire ERO invalid and send a PCErr message with Error-
Type = 10 ("Reception of an invalid object") and Error-value = 41
("Both SID and NAI are absent in the SRv6-ERO subobject").
If a PCC receives an SRv6-ERO subobject in which the S bit is set to
1 and the F bit is set to zero (that is, the SID is absent and the
NAI is present), but the PCC does not support NAI resolution, it MUST
consider the entire ERO invalid and send a PCErr message with Error-
Type = 4 ("Not supported object") and Error-value = 4 ("Unsupported
parameter").
If a PCC detects that the subobjects of an ERO are a mixture of SRv6-
ERO subobjects and subobjects of other types, then it MUST send a
PCErr message with Error-Type = 10 ("Reception of an invalid object")
and Error-value = 42 ("ERO mixes SRv6-ERO subobjects with other
subobject types").
In case a PCEP speaker receives an SRv6-ERO subobject, when the PST
is not set to 3 or SRv6-PCE-CAPABILITY sub-TLV was not exchanged, it
MUST send a PCErr message with Error-Type = 19 ("Invalid Operation")
and Error-Value = 19 ("Attempted SRv6 when the capability was not
advertised").
If a PCC receives an SRv6 path that exceeds the SRv6 MSD
capabilities, it MUST send a PCErr message with Error-Type = 10
("Reception of an invalid object") and Error-Value = 43 ("Unsupported
number of SRv6-ERO subobjects") as per [RFC8664].
5.2.2. Interpreting the SRv6-ERO
The SRv6-ERO contains a sequence of subobjects. According to
[RFC9256], each SRv6-ERO subobject in the sequence identifies a
segment that the traffic will be directed to, in the order given.
That is, the first subobject identifies the first segment the traffic
will be directed to, the second SRv6-ERO subobject represents the
second segment, and so on.
5.3. RRO Processing
The syntax checking rules that apply to the SRv6-RRO subobject are
identical to those of the SRv6-ERO subobject, except as noted below.
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If a PCEP speaker receives an SRv6-RRO subobject in which both SRv6
SID and NAI are absent, it MUST consider the entire RRO invalid and
send a PCErr message with Error-Type = 10 ("Reception of an invalid
object") and Error-Value = 35 ("Both SID and NAI are absent in
SRv6-RRO subobject").
If a PCE detects that the subobjects of an RRO are a mixture of
SRv6-RRO subobjects and subobjects of other types, then it MUST send
a PCErr message with Error-Type = 10 ("Reception of an invalid
object") and Error-Value = 36 ("RRO mixes SRv6-RRO subobjects with
other subobject types").
The mechanism by which the PCC learns the path is outside the scope
of this document.
6. Security Considerations
The security considerations described in [RFC5440], section 2.5 of
[RFC6952], [RFC8231], [RFC8281], [RFC8253] and [RFC8664] are
applicable to this specification.
Note that this specification enables a network controller to
instantiate an SRv6 path in the network. This creates an additional
vulnerability if the security mechanisms of [RFC5440], [RFC8231], and
[RFC8281] are not used. If there is no integrity protection on the
session, then an attacker could create an SRv6 path that may not
subjected to the further verification checks. Further, the MSD field
in the Open message could disclose node forwarding capabilities if
suitable security mechanisms are not in place. Hence, securing the
PCEP session using Transport Layer Security (TLS) [RFC8253] is
RECOMMENDED.
7. Manageability Considerations
All manageability requirements and considerations listed in
[RFC5440], [RFC8231], [RFC8281], and [RFC8664] apply to PCEP protocol
extensions defined in this document. In addition, requirements and
considerations listed in this section apply.
7.1. Control of Function and Policy
A PCEP implementation SHOULD allow the operator to configure the SRv6
capability. Further a policy to accept NAI only for the SRv6 SHOULD
be allowed to be set.
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7.2. Information and Data Models
The PCEP YANG module is out of the scope of this document and defined
in other documents, for example, [I-D.ietf-pce-pcep-yang]. An
augmented YANG module for SRv6 is also specified in another document
[I-D.ietf-pce-pcep-srv6-yang] that allows for SRv6 capability and MSD
configurations as well as to monitor the SRv6 paths set in the
network.
7.3. Liveness Detection and Monitoring
Mechanisms defined in this document do not imply any new liveness
detection and monitoring requirements in addition to those already
listed in [RFC5440].
7.4. Verify Correct Operations
Verification of the mechanisms defined in this document can be built
on those already listed in [RFC5440], [RFC8231], and [RFC8664].
7.5. Requirements On Other Protocols
Mechanisms defined in this document do not imply any new requirements
on other protocols.
7.6. Impact On Network Operations
Mechanisms defined in [RFC5440], [RFC8231], and [RFC8664] also apply
to PCEP extensions defined in this document.
8. Implementation Status
[Note to the RFC Editor - remove this section before publication, as
well as remove the reference to [RFC7942].
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.
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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".
8.1. Cisco's Commercial Delivery
* Organization: Cisco Systems, Inc.
* Implementation: IOS-XR PCE and PCC.
* Description: Implementation with experimental codepoints.
* Maturity Level: Production
* Coverage: Partial
* Contact: ssidor@cisco.com
8.2. Huawei's Commercial Delivery
* Organization: Huawei Technologies Co.,Ltd.
* Implementation: Huawei Routers and NCE Controller
* Description: Huawei has Implemented this draft to support PCE-
Initiated SRv6 Policy.
* Maturity Level: Production
* Coverage: Partial
* Contact: yuwei.yuwei@huawei.com
9. IANA Considerations
9.1. PCEP ERO and RRO subobjects
This document defines a new subobject type for the PCEP explicit
route object (ERO), and a new subobject type for the PCEP reported
route object (RRO). The code points for subobject types of these
objects is maintained in the RSVP parameters registry, under the
EXPLICIT_ROUTE and REPORTED_ROUTE objects. IANA is requested to
confirm the following allocations in the RSVP Parameters registry for
each of the new subobject types defined in this document.
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Object Subobject Subobject Type
--------------------- -------------------------- ------------------
EXPLICIT_ROUTE SRv6-ERO (PCEP-specific) 40
ROUTE_RECORD SRv6-RRO (PCEP-specific) 40
9.2. New SRv6-ERO NAI Type Registry
IANA is requested to create a new sub-registry, named "PCEP SRv6-ERO
NAI Types", within the "Path Computation Element Protocol (PCEP)
Numbers" registry to manage the 4-bit NT field in SRv6-ERO subobject.
The allocation policy for this new registry is by IETF
Review[RFC8126].The new registry contains the following values.
Value Description Reference
----- ----------- ---------
0 NAI is absent. This document
1 Unassigned
2 NAI is an IPv6 node ID. This document
3 Unassigned
4 NAI is an IPv6 adjacency This document
with global IPv6 addresses.
5 Unassigned
6 NAI is an IPv6 adjacency This document
with link-local IPv6 addresses.
7-15 Unassigned
9.3. New SRv6-ERO Flag Registry
IANA is requested to create a new sub-registry, named "SRv6-ERO Flag
Field", within the "Path Computation Element Protocol (PCEP) Numbers"
registry to manage the 12-bit Flag field of the SRv6-ERO subobject.
New values are to be assigned by Standards Action [RFC8126]. Each
bit should be tracked with the following qualities.
* Bit (counting from bit 0 as the most significant bit)
* Description
* Reference
The following values are defined in this document.
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Bit Description Reference
----- ------------------ --------------
0-7 Unassigned
8 SID Verification (V) This document
9 SID Structure is This document
present (T)
10 NAI is absent (F) This document
11 SID is absent (S) This document
9.4. LSP-ERROR-CODE TLV
This document defines a new value in the sub-registry "LSP-ERROR-CODE
TLV Error Code Field" in the "Path Computation Element Protocol(PCEP)
Numbers" registry.
Value Meaning Reference
--- ----------------------- -----------
TBD SID Verification fails This document
9.5. PATH-SETUP-TYPE-CAPABILITY Sub-TLV Type Indicators
IANA maintains a sub-registry, named "PATH-SETUP-TYPE-CAPABILITY Sub-
TLV Type Indicators", within the "Path Computation Element Protocol
(PCEP) Numbers" registry to manage the type indicator space for sub-
TLVs of the PATH-SETUP-TYPE-CAPABILITY TLV. IANA is requested to
confirm the following allocations in the sub-registry.
Value Meaning Reference
----- ------- ---------
27 SRv6-PCE-CAPABILITY This Document
9.6. SRv6 PCE Capability Flags
IANA is requested to create a new sub-registry, named "SRv6
Capability Flag Field", within the "Path Computation Element Protocol
(PCEP) Numbers" registry to manage the 16-bit Flag field of the SRv6-
PCE-CAPABILITY sub-TLV. New values are to be assigned by Standards
Action [RFC8126]. Each bit should be tracked with the following
qualities.
* Bit (counting from bit 0 as the most significant bit)
* Description
* Reference
The following values are defined in this document.
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Bit Description Reference
----- ------------------ --------------
0-13 Unassigned
14 Node or Adjacency This document
Identifier (NAI) is
supported (N)
15 Unassigned
9.7. New Path Setup Type
[RFC8408] created a sub-registry within the "Path Computation Element
Protocol (PCEP) Numbers" registry called "PCEP Path Setup Types".
IANA is requested to confirm the following allocations in the sub-
registry.
Value Description Reference
----- ----------- ---------
3 Traffic engineering path is This Document
setup using SRv6.
9.8. ERROR Objects
IANA is requested to confirm the following allocations in the PCEP-
ERROR Object Error Types and Values registry for the following new
error-values.
Error-Type Meaning
---------- -------
10 Reception of an invalid object
Error-value = 34 (Missing
PCE-SRv6-CAPABILITY sub-TLV)
Error-value = 35 (Both SID and NAI are absent
in SRv6-RRO subobject)
Error-value = 36 (RRO mixes SRv6-RRO subobjects
with other subobject types)
Error-value = 37 (Invalid SRv6 SID Structure)
19 Invalid Operation
Error-value = 19 (Attempted SRv6 when the
capability was not advertised)
IANA is requested to make a new allocations in the PCEP-ERROR Object
Error Types and Values registry for the following new error-values.
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Error-Type Meaning
---------- -------
10 Reception of an invalid object
Error-value = TBD (Unsupported number of
SRv6-ERO subobjects)
Error-value = TBD (Unsupported NAI Type
in the SRv6-ERO/SRv6-RRO subobject)
Error-value = TBD (Both SID and NAI are
absent in the SRv6-ERO subobject)
Error-value = TBD (ERO mixes SRv6-ERO
subobjects with other subobject types)
Error-value = TBD (Unsupported number
of SRv6-ERO subobjects)
10. References
10.1. Normative References
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
<https://www.rfc-editor.org/rfc/rfc3209>.
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009,
<https://www.rfc-editor.org/rfc/rfc5440>.
[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/rfc/rfc8126>.
[RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
Computation Element Communication Protocol (PCEP)
Extensions for Stateful PCE", RFC 8231,
DOI 10.17487/RFC8231, September 2017,
<https://www.rfc-editor.org/rfc/rfc8231>.
[RFC8281] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path
Computation Element Communication Protocol (PCEP)
Extensions for PCE-Initiated LSP Setup in a Stateful PCE
Model", RFC 8281, DOI 10.17487/RFC8281, December 2017,
<https://www.rfc-editor.org/rfc/rfc8281>.
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[RFC8408] Sivabalan, S., Tantsura, J., Minei, I., Varga, R., and J.
Hardwick, "Conveying Path Setup Type in PCE Communication
Protocol (PCEP) Messages", RFC 8408, DOI 10.17487/RFC8408,
July 2018, <https://www.rfc-editor.org/rfc/rfc8408>.
[RFC8491] Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg,
"Signaling Maximum SID Depth (MSD) Using IS-IS", RFC 8491,
DOI 10.17487/RFC8491, November 2018,
<https://www.rfc-editor.org/rfc/rfc8491>.
[RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody,
"PCEPS: Usage of TLS to Provide a Secure Transport for the
Path Computation Element Communication Protocol (PCEP)",
RFC 8253, DOI 10.17487/RFC8253, October 2017,
<https://www.rfc-editor.org/rfc/rfc8253>.
[RFC8664] Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
and J. Hardwick, "Path Computation Element Communication
Protocol (PCEP) Extensions for Segment Routing", RFC 8664,
DOI 10.17487/RFC8664, December 2019,
<https://www.rfc-editor.org/rfc/rfc8664>.
[RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
(SRv6) Network Programming", RFC 8986,
DOI 10.17487/RFC8986, February 2021,
<https://www.rfc-editor.org/rfc/rfc8986>.
[RFC9514] Dawra, G., Filsfils, C., Talaulikar, K., Ed., Chen, M.,
Bernier, D., and B. Decraene, "Border Gateway Protocol -
Link State (BGP-LS) Extensions for Segment Routing over
IPv6 (SRv6)", RFC 9514, DOI 10.17487/RFC9514, December
2023, <https://www.rfc-editor.org/rfc/rfc9514>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
10.2. Informative References
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[RFC4657] Ash, J., Ed. and J.L. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol Generic
Requirements", RFC 4657, DOI 10.17487/RFC4657, September
2006, <https://www.rfc-editor.org/rfc/rfc4657>.
[RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of
BGP, LDP, PCEP, and MSDP Issues According to the Keying
and Authentication for Routing Protocols (KARP) Design
Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013,
<https://www.rfc-editor.org/rfc/rfc6952>.
[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/rfc/rfc7942>.
[RFC8051] Zhang, X., Ed. and I. Minei, Ed., "Applicability of a
Stateful Path Computation Element (PCE)", RFC 8051,
DOI 10.17487/RFC8051, January 2017,
<https://www.rfc-editor.org/rfc/rfc8051>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/rfc/rfc8402>.
[RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J.,
Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
(SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,
<https://www.rfc-editor.org/rfc/rfc8754>.
[RFC9256] Filsfils, C., Talaulikar, K., Ed., Voyer, D., Bogdanov,
A., and P. Mattes, "Segment Routing Policy Architecture",
RFC 9256, DOI 10.17487/RFC9256, July 2022,
<https://www.rfc-editor.org/rfc/rfc9256>.
[RFC9352] Psenak, P., Ed., Filsfils, C., Bashandy, A., Decraene, B.,
and Z. Hu, "IS-IS Extensions to Support Segment Routing
over the IPv6 Data Plane", RFC 9352, DOI 10.17487/RFC9352,
February 2023, <https://www.rfc-editor.org/rfc/rfc9352>.
[I-D.ietf-pce-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-22, 11 September
2023, <https://datatracker.ietf.org/doc/html/draft-ietf-
pce-pcep-yang-22>.
Li, et al. Expires 18 August 2024 [Page 25]
Internet-Draft PCEP-SRv6 February 2024
[I-D.ietf-pce-pcep-srv6-yang]
Li, C., Sivabalan, S., Peng, S., Koldychev, M., and L.
Ndifor, "A YANG Data Model for Segment Routing (SR) Policy
and SR in IPv6 (SRv6) support in Path Computation Element
Communications Protocol (PCEP)", Work in Progress,
Internet-Draft, draft-ietf-pce-pcep-srv6-yang-04, 11
September 2023, <https://datatracker.ietf.org/doc/html/
draft-ietf-pce-pcep-srv6-yang-04>.
Acknowledgements
The authors would like to thank Jeff Tantsura, Adrian Farrel, Aijun
Wang, Khasanov Boris, Ketan Talaulikar, Martin Vigoureux, Hariharan
Ananthakrishnan, Xinyue Zhang, John Scudder, Julien Meuric and Robert
Varga for valuable suggestions.
Contributors
Mahendra Singh Negi
RtBrick Inc
Bangalore
Karnataka
India
Email: mahend.ietf@gmail.com
Dhruv Dhody
Huawei
India
Email: dhruv.ietf@gmail.com
Huang Wumin
Huawei Technologies
Huawei Building, No. 156 Beiqing Rd.
Beijing
100095
China
Email: huangwumin@huawei.com
Shuping Peng
Huawei Technologies
Huawei Building, No. 156 Beiqing Rd.
Beijing
100095
China
Email: pengshuping@huawei.com
Li, et al. Expires 18 August 2024 [Page 26]
Internet-Draft PCEP-SRv6 February 2024
Ran Chen
ZTE Corporation
China
Email: chen.ran@zte.com.cn
Authors' Addresses
Cheng Li(Editor)
Huawei Technologies
Huawei Campus, No. 156 Beiqing Rd.
Beijing
100095
China
Email: c.l@huawei.com
Prejeeth Kaladharan
RtBrick Inc
Bangalore
Karnataka
India
Email: prejeeth@rtbrick.com
Siva Sivabalan
Ciena Corporation
Email: msiva282@gmail.com
Mike Koldychev
Cisco Systems, Inc.
Canada
Email: mkoldych@cisco.com
Yongqing Zhu
China Telecom
109 West Zhongshan Ave, Tianhe District
Bangalore
Guangzhou,
P.R. China
Email: zhuyq8@chinatelecom.cn
Li, et al. Expires 18 August 2024 [Page 27]
