Hi Authors,
I have finished the shepherd review of
draft-ietf-pce-segment-routing-policy-cp-14. Please handle these comments
before we ship this I-D to IESG.
## Major
- Section 5.6, you need to add update: RFC 8231 in the draft metadata. This
should also be captured in the abstract. The prefered way is to clearly
identify the text in RFC8231 that is changing with "OLD:" and "NEW:"
format!
- Section 8, Security considerations need to also cover the non-SRPA TLVs
which are not considered in the current text.
## Query
- Section 4.1,
````
If the PCC receives a
PCInit message with the Association Source set not to the headend IP
but to some globally unique IP address that the headend owns, then
the PCC SHOULD accept the PCInit message and create the SRPA with the
Association Source that was sent in the PCInit message.
````
What is the purpose of this text? PCC should use the source as set by
the PCE - isn't it given? Am I missing something? Boris also pointed this
out in his review.
## Minor
- Abstract is not very useful for a non-expert. Maybe change something like
-
````
OLD:
A Segment Routing (SR) Policy is a non-empty set of SR Candidate
Paths, which share the same <headend, color, endpoint> tuple. SR
Policy is modeled in PCEP as an Association of one or more SR
Candidate Paths. PCEP extensions are defined to signal additional
attributes of an SR Policy. The mechanism is applicable to all SR
forwarding planes (MPLS, SRv6, etc.).
NEW:
Segment Routing (SR) allows a node to steer a packet flow along any
path. SR Policy is an ordered list of segments (i.e.,
instructions) that represent a source-routed policy. Packet flows
are steered into an SR Policy on a node where it is instantiated
called a headend node. An SR Policy is made of one or more candidate
paths.
This document specifies Path Computation Element Communication
Protocol (PCEP) extension to associate candidate paths of the SR
Policy. It applies equally to the SR-MPLS and Segment Routing over
IPv6 (SRv6) instantiations of segment routing.
END
````
- Similarly I find Introduction to be very light on details. Consider
adding text by looking through recently published RFCs for instance.
- Terminology:
```
OLD:
SRPA: SR Policy Association. PCEP ASSOCATION that describes the SR
Policy. Depending on discussion context, it refers to a PCEP
object or to a group of LSPs that belong to the Association.
NEW:
SRPA: SR Policy Association. A new association type 'SR Policy
Association' is used to group candidate paths belonging to the SR
Policy. Depending on discussion context, it can refer to the PCEP
ASSOCIATION object of SR Policy type or to a group of LSPs that
belong to the association.
END
```
- Section 4, please add this text at the start -
````
As per [RFC8697], LSPs are associated with other LSPs with which they
interact by adding them to a common association group. As described
in [RFC8697], the association group is uniquely identified by the
combination of the following fields in the ASSOCIATION object:
Association Type, Association ID, Association Source, and (if
present) Global Association Source or Extended Association ID,
referred to as Association Parameters.
````
- Section 4.2, since none of the TLV are multi-instance. Can we simplify
this text -
````
OLD:
Unless specifically stated otherwise, the TLVs listed in the
following sub-sections are assumed to be single instance. Meaning,
only one instance of the TLV SHOULD be present in the object and only
the first instance of the TLV SHOULD be interpreted and subsequent
instances SHOULD be ignored.
NEW:
This document specifies four new TLVs to be carried in the SRPA object.
Only one TLV instance of each type can be carried, and only the first
occurrence is processed. Any others MUST be ignored.
````
Also applicable to section 5!
- Section 4.2.2, consider changing the SHOULD to MUST in this section. I
could not think of a justification for SHOULD here!
- Section 5.1,
- please also state what happens if the TLVs are used without the
exchange of SRPOLICY-CAPABILITY TLV or the corresponding bit is unset.
Without it, what is the use of adding this TLV?
- Consider updating the description such as "P-flag: If set to '1' by a
PCEP speaker, the P flag indicates that the PCEP speaker supports the
handling of COMPUTATION-PRIORITY TLV for the SR Policy."
- please add "Unassigned bits MUST be set to '0' on transmission and
MUST be ignored on receipt."
- Section 5.2, I am unsure about the interaction between the unsetting of
P-flag (PCEP speaker does not support the TLV) and the default value (128
when the TLV is not present). Isn't it a bit weird?
- Section 5.3, should the use of this TLV be limited to SR-MPLS? Also can
ENLP value be converted into a registery maintained at
https://www.iana.org/assignments/segment-routing/segment-routing.xhtml
which can be referred by both PCE and BGP?
- Section 5.4, please add "The unassigned bits in the Flag octet MUST be
set to zero upon transmission and MUST be ignored upon receipt." Should
"Invalidation Reasons Flags" get a registry for ease of adding new flags in
future? In general, can the text in this section be tightened a little
bit? Examples - be explicit on who is sending and who is receiving for
instance. Also, consider adding a more detailed example to show the usage
of the flags better alongside PCEP message exchange.
- Section 5.5, please add normative reference to
draft-ietf-pce-binding-label-sid
- Section 6.5, are you refereing to the registry at
https://www.iana.org/assignments/segment-routing/segment-routing.xhtml, in
which case it is called "Segment Routing" and not "Segment Routing
Parameters". Also better to call the new registry being added as
subregistry.
- Section 10.2, please make RFC 8253 and RFC 7525 as normative references.
## Nits
- Expand PCEP and SR in the title
- Expand PCEP, SRv6 in the abstract
- Expand MBZ on first use. It is also better to state that the field is
ignored on receipt
- Section 4.2.2, add reference to RFC 9256 for Discriminator, as you have
done for other fields
- Section 4.2.4, add reference to RFC 9356 for Preference
- s/there needs to be a separate capability negotiation/a separate
capability negotiation is useful/
- Expand on first use OAM/PM/BFD
- Section 6, please update the text in subsections where the number of
assignments in tables do not match the introductory text.
I am also attaching the updated xml that could be a starting point for you
to work on -15 version.
Thanks!
Dhruv
<?xml version="1.0" encoding="US-ASCII"?>
<!-- This template is for creating an Internet Draft using xml2rfc,
which is available here: http://xml.resource.org. -->
<!DOCTYPE rfc SYSTEM "rfc2629.dtd" [
<!-- One method to get references from the online citation libraries.
There has to be one entity for each item to be referenced.
An alternate method (rfc include) is described in the references. -->
<!ENTITY RFC2119 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml";>
<!ENTITY RFC2629 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2629.xml";>
<!ENTITY RFC3552 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.3552.xml";>
<!ENTITY I-D.narten-iana-considerations-rfc2434bis SYSTEM "http://xml.resource.org/public/rfc/bibxml3/reference.I-D.narten-iana-considerations-rfc2434bis.xml";>
]>
<?xml-stylesheet type='text/xsl' href='rfc2629.xslt' ?>
<!-- used by XSLT processors -->
<!-- For a complete list and description of processing instructions (PIs),
please see http://xml.resource.org/authoring/README.html. -->
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(Here they are set differently than their defaults in xml2rfc v1.32) -->
<?rfc strict="yes" ?>
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<!-- control the table of contents (ToC) -->
<?rfc toc="yes"?>
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<?rfc tocdepth="4"?>
<!-- the number of levels of subsections in ToC. default: 3 -->
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<?rfc symrefs="yes"?>
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<?rfc sortrefs="no" ?>
<!-- sort the reference entries alphabetically -->
<!-- control vertical white space
(using these PIs as follows is recommended by the RFC Editor) -->
<?rfc compact="yes" ?>
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<?rfc subcompact="no" ?>
<!-- keep one blank line between list items -->
<!-- end of list of popular I-D processing instructions -->
<rfc category="std" docName="draft-ietf-pce-segment-routing-policy-cp-14" ipr="trust200902" updates="8231">
<!-- category values: std, bcp, info, exp, and historic
ipr values: full3667, noModification3667, noDerivatives3667
you can add the attributes updates="NNNN" and obsoletes="NNNN"
they will automatically be output with "(if approved)" -->
<!-- ***** FRONT MATTER ***** -->
<front>
<title abbrev="PCEP SR Policy">
Path Computation Element Communication Protocol (PCEP) Extensions for Segment Routing (SR) Policy Candidate Paths</title>
<author fullname="Mike Koldychev" initials="M." surname="Koldychev">
<organization>Cisco Systems, Inc.</organization>
<address>
<postal>
<street>2000 Innovation Drive</street>
<city>Kanata</city>
<region>Ontario</region>
<code>K2K 3E8</code>
<country>Canada</country>
</postal>
<email>mkold...@proton.me</email>
</address>
</author>
<author fullname="Siva Sivabalan" initials="S." surname="Sivabalan">
<organization>Ciena Corporation</organization>
<address>
<postal>
<street>385 Terry Fox Dr.</street>
<city>Kanata</city>
<region>Ontario</region>
<code>K2K 0L1</code>
<country>Canada</country>
</postal>
<email>ssiva...@ciena.com</email>
</address>
</author>
<author fullname="Colby Barth" initials="C." surname="Barth">
<organization>Juniper Networks, Inc.</organization>
<address>
<email>cba...@juniper.net</email>
</address>
</author>
<author fullname="Shuping Peng" initials="S." surname="Peng">
<organization>Huawei Technologies</organization>
<address>
<postal>
<street>Huawei Campus, No. 156 Beiqing Rd.</street>
<city>Beijing</city>
<region/>
<code>100095</code>
<country>China</country>
</postal>
<phone/>
<facsimile/>
<email>pengshup...@huawei.com</email>
<uri/>
</address>
</author>
<author fullname="Hooman Bidgoli" initials="H." surname="Bidgoli">
<organization>Nokia</organization>
<address>
<email>hooman.bidg...@nokia.com</email>
</address>
</author>
<date day="9" month="March" year="2024" />
<workgroup>PCE Working Group</workgroup>
<abstract>
<t>
Segment Routing (SR) allows a node to steer a packet flow along any
path. SR Policy is an ordered list of segments (i.e.,
instructions) that represent a source-routed policy. Packet flows
are steered into an SR Policy on a node where it is instantiated
called a headend node. An SR Policy is made of one or more candidate
paths.
This document specifies Path Computation Element Communication
Protocol (PCEP) extension to associate candidate paths of the SR
Policy. It applies equally to the SR-MPLS and Segment Routing over
IPv6 (SRv6) instantiations of segment routing.
</t>
</abstract>
<note title="Requirements Language">
<t>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 <xref target="RFC2119"/> <xref target="RFC8174"/> when, and only when, they
appear in all capitals, as shown here.</t>
</note>
</front>
<middle>
<section anchor="Introduction" title="Introduction">
<t>
<xref target="RFC8664"/> specifies extensions that allow PCEP to work with basic SR-TE paths.
<xref target="RFC8697"/> introduces a generic mechanism to create a grouping of LSPs, called an Association.
<xref target="RFC9256"/> introduces the SR Policy construct as a grouping of SR Candidate Paths.
</t>
<t>
This document extends <xref target="RFC8664"/> to support signaling SR Policy Candidate Paths and their attributes.
SR Policy is modeled in PCEP as an Association, where the SR Candidate Paths are the members of that Association.
Thus the PCE can take computation and control decisions about the Candidate Paths, with the additional knowledge that these Candidate Paths belong to the same SR Policy.
</t>
</section> <!-- Introduction -->
<section anchor="Terminology" title="Terminology">
<t>The following terminologies are used in this document:
<list style="hanging">
<t hangText="Endpoint:"> The IPv4 or IPv6 endpoint address of the SR Policy in question, as described in <xref target="RFC9256"/>.</t>
<t hangText="SRPA:"> SR Policy Association. A new association type 'SR Policy
Association' is used to group candidate paths belonging to the SR
Policy. Depending on discussion context, it can refer to the PCEP
ASSOCIATION object of SR Policy type or to a group of LSPs that
belong to the association. </t>
<t hangText="Association Parameters:"> As described in <xref target="RFC8697"/>, refers to the key data, that uniquely identifies the Association.</t>
<t hangText="Association Information:"> As described in <xref target="RFC8697"/>, refers to the non-key information about the Association.</t>
</list>
</t>
</section> <!-- Terminology -->
<section anchor="Overview" title="Overview">
<t>
The SR Policy is represented by a new type of PCEP Association, called the SR Policy Association (SRPA).
The SR Candidate Paths of an SR Policy are the PCEP LSPs within the same SRPA.
The subject of encoding multiple Segment Lists within an SR Policy Candidate Path is described in <xref target="I-D.ietf-pce-multipath"/>.
</t>
<t>The SRPA carries three pieces of information:
SR Policy Identifier, SR Policy Candidate Path Identifier, and SR Policy Candidate Path Attribute(s).</t>
<t>
This document also specify some additional information that is not encoded as part of SRPA: Computation Priority, Explicit Null Label Policy, Drop upon Invalid behavior, and Specified-BSID-only.
</t>
<section anchor="SRPolicyIdentifier" title="SR Policy Identifier">
<t>SR Policy Identifier uniquely identifies the SR Policy <xref target="RFC9256"/> within the network.
SR Policy Identifier MUST be the same for all SR Policy Candidate Paths in the same SRPA.
SR Policy Identifier MUST NOT change for a given SR Policy Candidate Path during its lifetime.
SR Policy Identifier MUST be different for different SRPAs.
When these rules are not satisfied, the PCEP speaker MUST send a PCErr message with
Error-Type = 26 "Association Error", Error Value = TBD7 "SR Policy Identifier Mismatch".
SR Policy Identifier consist of:</t>
<t>
<list style="symbols">
<t>Headend router where the SR Policy originates.</t>
<t>Color of SR Policy.</t>
<t>Endpoint of SR Policy.</t>
</list>
</t>
</section>
<section anchor="SRPolicyCandidatePathIdentifier" title="SR Policy Candidate Path Identifier">
<t>SR Policy Candidate Path Identifier uniquely identifies the SR Policy Candidate Path within the context of an SR Policy.
SR Policy Candidate Path Identifier MUST NOT change for a given LSP during its lifetime.
SR Policy Candidate Path Identifier MUST be different for distinct Candidate Paths within the same SRPA.
When these rules are not satisfied, the PCEP speaker MUST send a PCErr message with
Error-Type = 26 "Association Error", Error Value = TBD8 "SR Policy Candidate Path Identifier Mismatch".
SR Policy Candidate Path Identifier consist of:</t>
<t>
<list style="symbols">
<t>Protocol Origin.</t>
<t>Originator.</t>
<t>Discriminator.</t>
</list>
</t>
</section>
<section anchor="SRPolicyCandidatePathAttributes" title="SR Policy Candidate Path Attributes">
<t>SR Policy Candidate Path Attributes carry non-key information about the Candidate Path and MAY change during the lifetime of the LSP.
SR Policy Candidate Path Attributes consist of:</t>
<t>
<list style="symbols">
<t>Preference.</t>
<t>Optionally, the SR Policy Candidate Path name.</t>
<t>Optionally, the SR Policy name.</t>
</list>
</t>
</section>
</section> <!-- Overview -->
<section anchor="Association" title="SR Policy Association">
<t>
As per [RFC8697], LSPs are associated with other LSPs with which they
interact by adding them to a common association group. As described
in [RFC8697], the association group is uniquely identified by the
combination of the following fields in the ASSOCIATION object:
Association Type, Association ID, Association Source, and (if
present) Global Association Source or Extended Association ID,
referred to as Association Parameters.
</t>
<t>
<xref target="RFC8697"/> specify the ASSOCIATION Object with two Object-Types for IPv4 and IPv6 which includes the field "Association Type". This document defines a new Association type (6) "SR Policy Association" for SRPA.
</t>
<t>
This Association Type is dynamic in nature, thus operator-configured Association
Range MUST NOT be set for this Association type and MUST be ignored.
</t>
<t>
<xref target="RFC8697"/> specifies the mechanism for the capability advertisement of
the Association Types supported by a PCEP speaker by defining an
ASSOC-Type-List TLV to be carried within an OPEN object. This
capability exchange for the SR Policy Association Types MUST
be done before using the SRPA. Thus, the
PCEP speaker MUST include the SRPA Type (6) in
the ASSOC-Type-List TLV and MUST receive the same from the PCEP peer
before using SRPA.
</t>
<t>
A given LSP MUST belong to at most one SRPA, since an SR Policy Candidate Path cannot belong to multiple SR Policies.
If a PCEP speaker receives a PCEP message requesting to join more than one SRPA for the same LSP,
then the PCEP speaker MUST send a PCErr message with
Error-Type = 26 "Association Error", Error-Value = 7 "Cannot join the association group".
</t>
<section anchor="AssociationParameters" title="Association Parameters">
<t>
As per <xref target="RFC9256"/>,
an SR Policy is identified through the tuple <headend, color, endpoint>.
The headend is encoded in the 'Association Source' field in the ASSOCIATION object and
the color and endpoint are encoded as part of the Extended Association ID TLV.
</t>
<t>The Association Parameters (see <xref target="Terminology"/>) consist of:</t>
<t>
<list style="symbols">
<t>Association Type: set to 6 "SR Policy Association".</t>
<t>Association Source (IPv4/IPv6): set to the headend IP address.</t>
<t>Association ID (16-bit): set to "1" (this 16-bit field is not utilized, just set to a fixed value).</t>
<t>Extended Association ID TLV: encodes the Color and Endpoint of the SR Policy.</t>
</list>
</t>
<t>The Association Source MUST be set to the headend value of the SR Policy, as defined in <xref target="RFC9256"/> Section 2.1.
If the PCC receives a PCInit message with the Association Source set not to the headend IP but to some globally unique IP address that the headend owns,
then the PCC SHOULD accept the PCInit message and create the SRPA with the Association Source that was sent in the PCInit message.</t>
<t>The 16-bit Association ID field in the ASSOCIATION object MUST be set to the value of "1".</t>
<t>The Extended Association ID TLV MUST be included and it MUST be in the following format:</t>
<figure anchor="Extended-Association-ID-TLV-FORMAT" title="Extended Association ID TLV format">
<artwork align="center"><![CDATA[
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 = 31 | Length = 8 or 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Color |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Endpoint ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>Type: Extended Association ID TLV, type = 31 <xref target="RFC8697"/>.</t>
<t>Length: Either 8 or 20, depending on whether IPv4 or IPv6 address is encoded in the Endpoint field.</t>
<t>Color: SR Policy color value, non-zero as per <xref target="RFC9256"/> Section 2.1.</t>
<t>Endpoint: can be either IPv4 or IPv6.
This value MAY be different from the one contained in the Destination address field in the END-POINTS object, or in the Tunnel Endpoint Address field in the LSP-IDENTIFIERS TLV.</t>
<t>If the PCEP speaker receives an SRPA object
whose Association Parameters do not follow the above specification,
then the PCEP speaker MUST send PCErr message with
Error-Type = 26 "Association Error", Error-Value = TBD7 "SR Policy Identifier Mismatch".</t>
<t>The purpose of choosing the Association Parameters in this way is to guarantee that there is no possibility of a race condition when multiple PCEP speakers want to associate the same SR Policy at the same time. By adhering to this format, all PCEP speakers come up with the same Association Parameters independently of each other based on the SR Policy <xref target="RFC9256"/> parameters. Thus, there is no chance that different PCEP speakers will come up with different Association Parameters for the same SR Policy.</t>
<t>
The last hop of the computed SR Policy Candidate Path MAY differ from the Endpoint contained in the <headend, color, endpoint> tuple.
An example use case is to terminate the SR Policy before reaching the Endpoint and have decapsulated traffic go the rest of the way to the Endpoint node using the native IGP path(s).
In this example, the destination of the SR Policy Candidate Paths will be some node before the Endpoint, but the Endpoint value is still used at the head-end to steer traffic with that Endpoint IP into the SR Policy.
Destination of the SR Policy Candidate Path is signaled using the END-POINTS object and/or LSP-IDENTIFIERS TLV, as per the usual PCEP procedures.
When neither END-POINTS object nor LSP-IDENTIFIERS TLV is present,
the PCEP speaker MUST extract the destination from the Endpoint field in the SRPA Extended Association ID TLV.
</t>
</section> <!-- AssociationParameters -->
<section anchor="AssociationInformation" title="Association Information">
<t>The SRPA object may carry the following TLVs:</t>
<t>
<list style="symbols">
<t>SRPOLICY-POL-NAME TLV: (optional) encodes SR Policy Name string.</t>
<t>SRPOLICY-CPATH-ID TLV: (mandatory) encodes SR Policy Candidate Path Identifier.</t>
<t>SRPOLICY-CPATH-NAME TLV: (optional) encodes SR Policy Candidate Path string name.</t>
<t>SRPOLICY-CPATH-PREFERENCE TLV: (optional) encodes SR Policy Candidate Path preference value.</t>
</list>
</t>
<t>Out of these TLVs, the SRPOLICY-CPATH-ID TLV is mandatory, all others are optional.
When a mandatory TLV is missing from the SRPA object, the PCEP speaker MUST send a PCErr message with
Error-Type = 6 "Mandatory Object Missing", Error-Value = TBD6 "Missing SR Policy Mandatory TLV".</t>
<t>This document specifies four new TLVs to be carried in the SRPA object. Only one TLV instance of each type can be carried, and only the first occurrence is processed. Any others MUST be ignored.</t>
<section anchor="Policy-name-tlv" title="SR Policy Name TLV">
<t>
The SRPOLICY-POL-NAME TLV is an optional TLV for the SRPA object.
</t>
<figure anchor="SRPOLICY-POL-NAME-TLV-FORMAT" title="The SRPOLICY-POL-NAME TLV format">
<artwork align="center"><![CDATA[
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ SR Policy Name ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>Type: 56 for "SRPOLICY-POL-NAME" TLV.</t>
<t>Length: indicates the length of the value portion of the TLV in octets and MUST be greater than 0. The TLV MUST be zero-padded so that the TLV is 4-octet aligned.</t>
<t>SR Policy Name: SR Policy name, as defined in <xref target="RFC9256"/>. It SHOULD be a string of printable ASCII characters, without a NULL terminator.</t>
</section> <!-- Policy-name-tlv -->
<section anchor="Cpath-identifier-tlv" title="SR Policy Candidate Path Identifier TLV">
<t>
The SRPOLICY-CPATH-ID TLV is a mandatory TLV for the SRPA object.
</t>
<figure anchor="SRPOLICY-CPATH-ID-TLV-FORMAT" title="The SRPOLICY-CPATH-ID TLV format">
<artwork align="center"><![CDATA[
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Proto. Origin | MBZ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originator ASN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Originator Address |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Discriminator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>Type: 57 for "SRPOLICY-CPATH-ID" TLV.</t>
<t>Length: 28.</t>
<t>Protocol Origin: 8-bit value that encodes the protocol origin, as specified in <xref target="protocol_origin"/>.
Note that in PCInitiate message <xref target="RFC8281"/>, the Protocol Origin is always set to 10 (PCEP). </t>
<t>MBZ: Must be zero.</t>
<t>Originator ASN: Represented as 4-byte number, part of the originator identifier, as specified in <xref target="RFC9256"/> Section 2.4. If 2-byte ASNs are in use, the low-order 16 bits is used, and the high-order bits are set to 0.
When sending PCInitiate message <xref target="RFC8281"/>, the PCE is acting as the originator and therefore SHOULD set this to an ASN that it belongs to.
</t>
<t>Originator Address: Represented as 128-bit value where IPv4 address is encoded in lowest 32 bits and high-order bits are set to 0, part of the originator identifier, as specified in <xref target="RFC9256"/> Section 2.4. When sending PCInitiate message, the PCE is acting as the originator and therefore SHOULD set this to an address that it owns.
</t>
<t>Discriminator: 32-bit value that encodes the Discriminator of the Candidate Path, as specified in <xref target="RFC9256"/> Section 2.5.
This is the field that mainly distinguishes different SR Candidate Paths, coming from the same originator. It is allowed to be any number in the 32-bit range.
</t>
</section> <!-- Cpath-identifier-tlv -->
<section anchor="SRPOLICY-CPATH-NAME" title="SR Policy Candidate Path Name TLV">
<t>
The SRPOLICY-CPATH-NAME TLV is an optional TLV for the SRPA object.
</t>
<figure anchor="SRPOLICY-CPATH-NAME-TLV-FORMAT" title="The SRPOLICY-CPATH-NAME TLV format">
<artwork align="center"><![CDATA[
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ SR Policy Candidate Path Name ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>Type: 58 for "SRPOLICY-CPATH-NAME" TLV.</t>
<t>Length: indicates the length of the value portion of the TLV in octets and MUST be greater than 0. The TLV MUST be zero-padded so that the TLV is 4-octet aligned.</t>
<t>SR Policy Candidate Path Name: SR Policy Candidate Path Name, as defined in <xref target="RFC9256"/>. It SHOULD be a string of printable ASCII characters, without a NULL terminator.</t>
</section> <!-- SRPOLICY-CPATH-NAME -->
<section anchor="Cpath-preference-tlv" title="SR Policy Candidate Path Preference TLV">
<t>
The SRPOLICY-CPATH-PREFERENCE TLV is an optional TLV for the SRPA object.
If the TLV is absent, then default Preference value is 100, as per Section 2.7 of <xref target="RFC9256"/>.
</t>
<figure anchor="SRPOLICY-CPATH-PREFERENCE-TLV-FORMAT" title="The SRPOLICY-CPATH-PREFERENCE TLV format">
<artwork align="center"><![CDATA[
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Preference |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>Type: 59 for "SRPOLICY-CPATH-PREFERENCE" TLV.</t>
<t>Length: 4.</t>
<t>Preference: Numerical preference of the Candidate Path as defined in Section 2.7 of <xref target="RFC9256"/>.</t>
</section> <!-- Cpath-preference-tlv -->
</section> <!-- AssociationInformation -->
</section> <!-- Association -->
<section anchor="Other-mechanisms" title="Other Mechanisms">
<t>This section describes mechanisms that are standardized
for SR Policies in <xref target="RFC9256"/>,
but do not make use of the SRPA for signaling in PCEP.
Since SRPA is not used, there needs to be a separate capability
negotiation.</t>
<t>
This document specifies four new TLVs to be carried in the OPEN or LSP object.
Only one TLV instance of each type can be carried, and only the first
occurrence is processed. Any others MUST be ignored.
</t>
<section anchor="Capability-tlv" title="SR Policy Capability TLV">
<t>
The SRPOLICY-CAPABILITY TLV is an optional TLV for the OPEN object.
It is used at session establishment time to learn the other PCEP peer's
capabilities with respect to SR Policy.
</t>
<figure anchor="SRPOLICY-CAPABILITY-TLV-FORMAT" title="The SRPOLICY-CAPABILITY TLV format">
<artwork align="center"><![CDATA[
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags |L|S|I|E|P|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>Type: TBD4 for "SRPOLICY-CAPABILITY TLV.</t>
<t>Length: 4.</t>
<t>P-flag: If set to '1' by a PCEP speaker, the P flag indicates that the PCEP speaker supports the handling of COMPUTATION-PRIORITY TLV for the SR Policy, see <xref target="Computation-priority-tlv"/>.</t>
<t>E-Flag: PCEP speaker supports the ENLP TLV with SR Policy,
see <xref target="enlp-tlv"/>.</t>
<t>I-Flag: PCEP speaker supports INVALIDATION TLV with SR Policy,
see <xref target="Invalidation-tlv"/>.</t>
<t>S-Flag: PCEP speaker supports "Specified-BSID-only" behavior with SR Policy,
see <xref target="Specified-bsid-only"/>.</t>
<t>L-Flag: PCEP speaker supports stateless (PCReq/PCRep) operations with SR Policy,
see <xref target="Stateless-oper"/>.</t>
<t>Unassigned bits MUST be set to '0' on transmission and MUST be ignored on receipt.</t>
</section> <!-- Capability-tlv -->
<section anchor="Computation-priority-tlv" title="Computation Priority TLV">
<t>The COMPUTATION-PRIORITY TLV is an optional TLV for the LSP object.
It is used to signal the numerical computation priority, as specified in Section 2.12 of <xref target="RFC9256"/>.
If the TLV is absent from the LSP object, a default Priority value of 128 is used.</t>
<figure anchor="COMPUTATION-PRIORITY-TLV-FORMAT" title="The COMPUTATION-PRIORITY TLV format">
<artwork align="center"><![CDATA[
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Priority | MBZ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>Type: TBD1 for "COMPUTATION-PRIORITY" TLV.</t>
<t>Length: 4.</t>
<t>Priority: Numerical priority with which this LSP is to be recomputed by the PCE upon topology change.</t>
</section> <!-- Computation-priority-tlv -->
<section anchor="enlp-tlv" title="Explicit Null Label Policy (ENLP) TLV">
<t>
To steer an unlabeled IP packet into an SR policy, it is necessary to create a label stack for that packet, and push one or more labels onto that stack.
The Explicit NULL Label Policy (ENLP) TLV is an optional TLV used to indicate whether an Explicit NULL Label <xref target="RFC3032"/> must be pushed on an unlabeled IP packet before any other labels.
The contents of this TLV are used by the SRPM as described in section 4.1 of <xref target="RFC9256"/>.
If an ENLP TLV is not present, the decision of whether to push an Explicit NULL label on a given packet is a matter of local configuration.
</t>
<figure anchor="ENLP-TLV-FORMAT" title="The Explicit Null Label Policy (ENLP) TLV format">
<artwork align="center"><![CDATA[
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ENLP | MBZ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>Type: TBD2 for "ENLP" TLV.</t>
<t>Length: 4.</t>
<t>
ENLP (Explicit NULL Label Policy): Indicates whether Explicit NULL labels are to be pushed on unlabeled IP packets
that are being steered into a given SR policy. This field has one of the following values:
</t>
<t>
<list style="symbols">
<t>
0: Reserved.
</t>
<t>
1: Push an IPv4 Explicit NULL label on an unlabeled IPv4 packet, but do not push an IPv6 Explicit NULL label on an unlabeled IPv6 packet.
</t>
<t>
2: Push an IPv6 Explicit NULL label on an unlabeled IPv6 packet, but do not push an IPv4 Explicit NULL label on an unlabeled IPv4 packet.
</t>
<t>
3: Push an IPv4 Explicit NULL label on an unlabeled IPv4 packet, and push an IPv6 Explicit NULL label on an unlabeled IPv6 packet.
</t>
<t>
4: Do not push an Explicit NULL label.
</t>
<t>
5 - 255: Reserved.
</t>
</list>
</t>
<t>
The ENLP reserved values may be used for future extensions and implementations SHOULD ignore the ENLP TLV with these values.
The behavior signaled in this TLV MAY be overridden by local configuration.
The section 4.1 of <xref target="RFC9256"/> describes the behavior on the headend for the handling of the explicit null label.
</t>
</section> <!-- enlp-tlv -->
<section anchor="Invalidation-tlv" title="Invalidation TLV">
<t>The INVALIDATION TLV is an optional TLV for the LSP object.
It is used to control traffic steering into the LSP
during the time when the LSP is operationally down/invalid.
In the context of SR Policy, this TLV facilitates
the "Drop upon invalid" behavior,
specified in Section 8.2 of <xref target="RFC9256"/>.
Normally, if the LSP is down/invalid then it stops attracting traffic and
traffic that is originally destined for that LSP
is redirected somewhere else, such as via IGP or via another LSP.
The "Drop upon invalid" behavior specifies that the LSP keeps attracting traffic
and the traffic has to be dropped at the head-end.
Such an LSP is said to be "in drop state".
While in the drop state, the LSP operational state is "UP",
as indicated by the O-flag in the LSP object.
However the ERO object MAY be empty, if no valid path has been computed.
</t>
<t>
The INVALIDATION TLV is used in both directions between PCEP peers:
<list style="symbols">
<t>PCE -> PCC: PCE specifies to the PCC under what conditions the LSP should enter the drop state.</t>
<t>PCC -> PCE: PCC reports under what conditions the LSP will enter the drop state and the PCC also reports whether the LSP is currently in the drop state and if so, for what reason.</t>
</list>
</t>
<t>
Reasons for entering the drop state are represented by a set of flags.
</t>
<figure anchor="INVAL_FLAGS" title="Invalidation Reasons Flags">
<artwork align="center"><![CDATA[
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| |V|P|F|G|
+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>
<list style="symbols">
<t>G: Generic - does not fit into any other categories below.</t>
<t>F: First-hop resolution failure - head-end first hop resolution has failed.</t>
<t>P: Path computation failure - no path was computed for the LSP.</t>
<t>V: Verification failure - OAM/PM/BFD path verification has indicated a breakage.</t>
<t>The unassigned bits in the Flag octet MUST be set to zero upon transmission and MUST be ignored upon receipt.</t>
</list>
</t>
<figure anchor="INVALIDATION-TLV-FORMAT" title="The INVALIDATION TLV format">
<artwork align="center"><![CDATA[
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inval Reason | Drop Upon | MBZ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>Type: TBD3 for "INVALIDATION" TLV.</t>
<t>Length: 4.</t>
<t>Inval Reason: contains "Invalidation Reasons Flags" which encode the
reason(s) why the LSP is currently invalidated.
This field can be set to non-zero values only by the PCC,
it MUST be set to 0 by the PCE and ignored by the PCC.
</t>
<t>Drop Upon: contains "Invalidation Reasons Flags" for conditions
that SHOULD cause the LSP to enter drop state.
This field can be set to non-zero values by both PCC and PCE.
When the G-flag is set, this indicates that the LSP is to go into
Drop upon invalid state for any reason. I.e., when the PCE does not wish to
distinguish any reason for LSP invalidation and just simply wants it to
always go into drop state whenever the LSP is down.
Note that when the G-flag is set, the values of the other flags are irrelevant.
</t>
<t>
Note that out of all the "Invalidation Reasons Flags", only the G-flag (Generic)
MUST be supported.
The other flags can simply be ignored if they are not supported by the PCEP speaker.
For example, suppose the PCC only supports P-flag and G-flag.
When this PCC receives this TLV with Drop Upon set to 0x6 (P,F),
then the PCC responds with Drop Upon = 0x4 (P).
When this PCC receives this TLV with Drop Upon set to 0x7 (P,F,G),
then the PCC responds with Drop Upon = 0x5 (P,G).
</t>
</section> <!-- Invalidation-tlv -->
<section anchor="Specified-bsid-only" title="Specified-BSID-only">
<t>Specified-BSID-only functionality is defined in Section 6.2.3 of <xref target="RFC9256"/>.
When specified-BSID-only is enabled for a particular binding SID, it means that the given binding SID is required to be allocated and programmed for the LSP to be operationally up.
If the binding SID cannot be allocated or programmed for some reason, then the LSP must stay down.</t>
<t>To signal specified-BSID-only, a new bit: S (Specified-BSID-only) is allocated in the "TE-PATH-BINDING TLV Flag field" of the TE-PATH-BINDING TLV <xref target="I-D.ietf-pce-binding-label-sid"/>.
When this bit is set for a particular BSID, it means that the BSID follows the Specified-BSID-only behavior.
It is possible to have a mix of BSIDs for the same LSP: some with S=1 and some with S=0.</t>
</section> <!-- Specified-bsid-only -->
<section anchor="Stateless-oper" title="Stateless Operation">
<t>
<xref target="RFC8231"/> Section 5.8.2, allows delegation of an LSP in operationally down state,
but at the same time mandates the use of PCReq before sending PCRpt.
This document modifies the procedure of <xref target="RFC8231"/> Section 5.8.2,
for SR Policies we make sending of PCReq before PCRpt OPTIONAL.
Thus, when a PCC wants to delegate an SR Policy LSP, it MAY proceed directly to sending PCRpt,
without first sending PCReq and waiting for PCRep.
This has the advantage of reducing the number of PCEP messages and simplifying the implementation.
</t>
<t>
Furthermore, a PCEP speaker is not required to support PCReq/PCRep at all for SR Policies.
The PCEP speaker can indicate support for PCReq/PCRep via the "L-Flag" in
the SRPOLICY-CAPABILITY TLV (See <xref target="Capability-tlv"/>).
When this flag is cleared, or when the SRPOLICY-CAPABILITY TLV is absent,
the given peer SHOULD NOT be sent PCReq/PCRep messages for SR Policy LSPs.
Conversely when this flag is set, the peer can receive and process
PCReq/PCRep messages for SR Policy LSPs.
</t>
<t>
The above applies only to SR Policy LSPs and does not affect other LSP types,
such as RSVP-TE LSPs. For other LSP types, <xref target="RFC8231"/> Section 5.8.2
continues to apply.
</t>
</section> <!-- Stateless-oper -->
</section> <!-- Other mechanisms -->
<section title="IANA Considerations">
<section title="Association Type">
<t>This document defines a new association type: SR Policy Association.
IANA is requested to make the following codepoint assignment in the
"ASSOCIATION Type Field" subregistry <xref target="RFC8697"/> within
the "Path Computation Element Protocol (PCEP) Numbers" registry:</t>
<t>
<figure>
<artwork align="left"><![CDATA[
+-----------+-------------------------------------------+-----------+
| Type | Name | Reference |
+-----------+-------------------------------------------+-----------+
| 6 | SR Policy Association | This.I-D |
+-----------+-------------------------------------------+-----------+
]]></artwork>
</figure>
</t>
</section>
<section title="PCEP TLV Type Indicators">
<t>This document defines eight new TLVs for carrying additional information about SR Policy and SR Candidate Paths. IANA is requested to make the assignment of a new value for the existing "PCEP TLV Type Indicators" subregistry as follows:</t>
<t>
<figure>
<artwork align="left"><![CDATA[
+-----------+-------------------------------------------+-----------+
| Value | Description | Reference |
+-----------+-------------------------------------------+-----------+
| 56 | SRPOLICY-POL-NAME | This.I-D |
+-----------+-------------------------------------------+-----------+
| 57 | SRPOLICY-CPATH-ID | This.I-D |
+-----------+-------------------------------------------+-----------+
| 58 | SRPOLICY-CPATH-NAME | This.I-D |
+-----------+-------------------------------------------+-----------+
| 59 | SRPOLICY-CPATH-PREFERENCE | This.I-D |
+-----------+-------------------------------------------+-----------+
| TBD1 | COMPUTATION-PRIORITY | This.I-D |
+-----------+-------------------------------------------+-----------+
| TBD2 | EXPLICIT-NULL-LABEL-POLICY | This.I-D |
+-----------+-------------------------------------------+-----------+
| TBD3 | INVALIDATION | This.I-D |
+-----------+-------------------------------------------+-----------+
| TBD4 | SRPOLICY-CAPABILITY | This.I-D |
+-----------+-------------------------------------------+-----------+
]]></artwork>
</figure>
</t>
</section>
<section title="PCEP Errors">
<t>This document defines one new Error-Value within the "Mandatory Object Missing" Error-Type and two new Error-Values within the "Association Error" Error-Type.
IANA is requested to allocate new error values within the "PCEP-ERROR Object Error Types and Values" subregistry of the PCEP Numbers registry, as follows:</t>
<t>
<figure>
<artwork align="left"><![CDATA[
+------------+------------------+-----------------------+-----------+
| Error-Type | Meaning | Error-value | Reference |
+------------+------------------+-----------------------+-----------+
| 6 | Mandatory Object | | [RFC5440] |
| | Missing | | |
+------------+------------------+-----------------------+-----------+
| | | TBD6: Missing SR | This.I-D |
| | | Policy Mandatory TLV | |
+------------+------------------+-----------------------+-----------+
| 26 | Association | | [RFC8697] |
| | Error | | |
+------------+------------------+-----------------------+-----------+
| | | TBD7: SR Policy | This.I-D |
| | | Identifers Mismatch | |
+------------+------------------+-----------------------+-----------+
| | | TBD8: SR Policy | This.I-D |
| | | Candidate Path | |
| | | Identifier Mismatch | |
+------------+------------------+-----------------------+-----------+
]]></artwork>
</figure>
</t>
</section>
<section title="TE-PATH-BINDING TLV Flag field">
<t>
IANA is requested to allocate new bit within the "TE-PATH-BINDING TLV Flag field" subregistry of the PCEP Numbers registry, as follows:</t>
<t>
<figure>
<artwork align="left"><![CDATA[
+------------+------------------------------------------+-----------+
| Bit position | Description | Reference |
+--------------+----------------------------------------+-----------+
| TBD9 | S (Specified-BSID-only) | This.I-D |
+--------------+----------------------------------------+-----------+
]]></artwork>
</figure>
</t>
</section>
<section anchor="protocol_origin" title="SR Policy Candidate Path Protocol Origin field">
<t>
This document requests IANA to maintain a new registry under
"Segment Routing" registry group.
New values are to be assigned by "Standards Action" [RFC8126].
The new subregistry is requested to be created under it be called "SR Policy Protocol Origin".
The subregistry contains the following codepoints, with initial values, to
be assigned by IANA with the reference set to this document:
</t>
<figure>
<artwork align="left"><![CDATA[
+------------+------------------------------------------------------+
| Value | Description |
+--------------+----------------------------------------------------+
| 0 | Reserved (not to be used) |
+--------------+----------------------------------------------------+
| 1-9 | Unassigned |
+--------------+----------------------------------------------------+
| 10 | PCEP |
+--------------+----------------------------------------------------+
| 11-19 | Unassigned |
+--------------+----------------------------------------------------+
| 20 | BGP SR Policy |
+--------------+----------------------------------------------------+
| 21-29 | Unassigned |
+--------------+----------------------------------------------------+
| 30 | Configuration (CLI, YANG model via NETCONF, etc.) |
+--------------+----------------------------------------------------+
| 31-250 | Unassigned |
+--------------+----------------------------------------------------+
| 251 - 255 | Private Use (not to be assigned by IANA) |
+--------------+----------------------------------------------------+
]]></artwork>
</figure>
</section>
</section>
<section title="Implementation Status">
<t>[Note to the RFC Editor - remove this section before publication, as
well as remove the reference to RFC 7942.]</t>
<t>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 <xref
target="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.</t>
<t>According to <xref target="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".</t>
<section anchor="Cisco" title="Cisco">
<t><list style="symbols">
<t>Organization: Cisco Systems</t>
<t>Implementation: IOS-XR PCC and PCE.</t>
<t>Description: All features supported except Computation Priority, Explicit NULL and Invalidation Drop.</t>
<t>Maturity Level: Production.</t>
<t>Coverage: Full.</t>
<t>Contact: mkold...@cisco.com</t>
</list></t>
</section>
<section anchor="Juniper" title="Juniper">
<t><list style="symbols">
<t>Organization: Juniper Networks</t>
<t>Implementation: PCC and PCE.</t>
<t>Description: Everything in -05 except SR Policy Name TLV and SR Policy Candidate Path Name TLV.</t>
<t>Maturity Level: Production.</t>
<t>Coverage: Partial.</t>
<t>Contact: cba...@juniper.net</t>
</list></t>
</section>
</section>
<section title="Security Considerations">
<t>This document defines one new type for ASSOCIATION object, which does not add any new
security concerns beyond those discussed in <xref target="RFC5440"/>,
<xref target='RFC8231'/>, <xref target="RFC8664"/> and <xref target='RFC8697'/> in itself.
</t>
<t>
The information carried in the SRPA object, as per this document is related to SR Policy.
It often reflects information
that can also be derived from the SR Database, but association provides a much easier grouping of related LSPs and messages.
The SRPA could provide an adversary with the opportunity to eavesdrop on the relationship between the LSPs.
Thus securing the PCEP session using Transport Layer
Security (TLS) <xref target="RFC8253"/>, as per the recommendations and
best current practices in <xref target="RFC7525"/>, is RECOMMENDED.</t>
</section>
<section anchor="Acknowledgement" title="Acknowledgement">
<t>
Would like to thank Stephane Litkowski, Boris Khasanov, Abdul Rehman, Alex Tokar, Praveen Kumar and Tom Petch for review and suggestions.
</t>
</section> <!-- Acknowledgement -->
</middle>
<back>
<references title="Normative References">
<?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml";?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.5440.xml";?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.8174.xml";?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.8231.xml";?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.8281.xml";?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.7942.xml";?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.9256.xml";?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.8697.xml";?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.8664.xml";?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.3032.xml";?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.7525.xml";?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.8253.xml";?>
<?rfc include="http://xml.resource.org/public/rfc/bibxml3/reference.I-D.ietf-pce-binding-label-sid.xml";?>
</references>
<references title="Informative References">
<?rfc include="http://xml.resource.org/public/rfc/bibxml3/reference.I-D.ietf-pce-multipath.xml";?>
<!--<?rfc include="http://xml.resource.org/public/rfc/bibxml3/reference.I-D.sivabalan-pce-binding-label-sid";?>-->
</references>
<section title="Contributors">
<t><figure><artwork>
Dhruv Dhody
Huawei
India
Email: dhruv.i...@gmail.com
Cheng Li
Huawei Technologies
Huawei Campus, No. 156 Beiqing Rd.
Beijing, 10095
China
Email: chengl...@huawei.com
Samuel Sidor
Cisco Systems, Inc.
Eurovea Central 3.
Pribinova 10
811 09 Bratislava
Slovakia
Email: ssi...@cisco.com
</artwork></figure></t>
</section> <!-- Contributors -->
</back>
</rfc>
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