PCE Working Group
Internet Engineering Task Force (IETF) S. Litkowski
Internet-Draft
Request for Comments: 9005 Cisco Systems, Inc.
Intended status:
Category: Standards Track S. Sivabalan
Expires: July 25, 2021
ISSN: 2070-1721 Ciena
J. Tantsura
Apstra, Inc.
Juniper Networks
J. Hardwick
Metaswitch Networks
C. Li
Huawei Technologies
January 21,
李呈 (C. Li)
华为技术有限公司 (Huawei Technologies)
March 2021
Path Computation Element (PCE) Communication Protocol (PCEP) extension Extension for associating
Associating Policies and Label Switched Paths (LSPs)
draft-ietf-pce-association-policy-16
Abstract
This document introduces a simple mechanism to associate policies to
with a group of Label Switched Paths (LSPs) via an extension to the
Path Computation Element (PCE) Communication Protocol (PCEP). The
extension allows a PCEP speaker to advertise to a PCEP peer that a
particular LSP belongs to a particular Policy Association Group. Group
(PAG).
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 an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list It represents the consensus of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid the IETF community. It has
received public review and has been approved for a maximum publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of six months this document, any errata,
and how to provide feedback on it may be updated, replaced, or obsoleted by other documents obtained at any
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 25, 2021.
https://www.rfc-editor.org/info/rfc9005.
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Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Policy based Policy-Based Constraints . . . . . . . . . . . . . . . . 5
4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5. Policy Association Group . . . . . . . . . . . . . . . . . . 7
5.1. Policy Parameters TLV . . . . . . . . . . . . . . . . . . 7 POLICY-PARAMETERS-TLV
6. Implementation Status . . . . . . . . . . . . . . . . . . . . 9
6.1. Cisco's Implementation . . . . . . . . . . . . . . . . . 9
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8.
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
8.1. Association object
7.1. ASSOCIATION Object Type Indicators . . . . . . . . . . . 10
8.2.
7.2. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . 10
8.3.
7.3. PCEP Errors . . . . . . . . . . . . . . . . . . . . . . . 11
9.
8. Manageability Considerations . . . . . . . . . . . . . . . . 11
9.1.
8.1. Control of Function and Policy . . . . . . . . . . . . . 11
9.2.
8.2. Information and Data Models . . . . . . . . . . . . . . . 11
9.3.
8.3. Liveness Detection and Monitoring . . . . . . . . . . . . 12
9.4. Verify
8.4. Verifying Correct Operations . . . . . . . . . . . . . . . . 12
9.5.
8.5. Requirements on Other Protocols . . . . . . . . . . . . . 12
9.6.
8.6. Impact on Network Operations . . . . . . . . . . . . . . 12
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12
11.
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
11.1.
9.1. Normative References . . . . . . . . . . . . . . . . . . 13
11.2.
9.2. Informative References . . . . . . . . . . . . . . . . . 13
Appendix A. Example of Policy Parameters . . . . . . . . . . . . 15
Appendix B. Contributor Addresses . . . . . . . . . . . . . . . 15
Acknowledgments
Contributors
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction
[RFC5440] describes the Path Computation Element Communication
Protocol (PCEP) (PCEP), which enables the communication between a Path
Computation Client (PCC) and a Path Control Element (PCE), (PCE) or between
two PCEs based on the PCE architecture [RFC4655]. [RFC5394] provides
additional details on policy within the PCE architecture and also
provides context for the support of PCE Policy.
PCEP policy.
"Path Computation Element Communication Protocol (PCEP) Extensions
for Stateful PCE Model [RFC8231] PCE" ([RFC8231]) describes a set of extensions to PCEP
to enable active control of Multiprotocol Label Switching Traffic
Engineering (MPLS-TE) and Generalized MPLS (GMPLS) tunnels.
[RFC8281] describes the set-up setup and teardown of PCE-
initiated PCE-initiated LSPs
under the active stateful PCE model, model without the need for local
configuration on the PCC, thus allowing for a dynamic network.
Currently, the LSPs can either be signaled via Resource Reservation
Protocol Traffic Engineering (RSVP-TE) or can be segment routed as specified
in [RFC8664].
[RFC8697] introduces a generic mechanism to create a grouping of LSPs
which
that can then be used to define associations between a set of LSPs
and a set of attributes (such as configuration parameters or
behaviors) and is equally applicable to stateful PCE (active and
passive modes) and stateless PCE.
This document specifies a PCEP extension to associate one or more
LSPs with policies using the generic association mechanism.
A PCEP speaker may want to influence the PCEP peer with respect to
path selection and other policies. This document describes a PCEP
extension to associate policies by creating a Policy Association
Group (PAG) and encoding this association in PCEP messages. The
specification is applicable to both stateful and stateless PCEP
sessions.
Note that the actual policy definition and the associated parameters
are out of scope of this document.
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
The following terminology is used in this document.
Association parameters: As described in [RFC8697], the combination
of the mandatory fields Association type, Type, Association ID ID, and
Association Source in the ASSOCIATION object uniquely identify identifies
the association group. If the optional TLVs - -- Global Association
Source or Extended Association ID -- are included, then they are
included in combination with mandatory fields to uniquely identify
the association group.
Association information: As described in [RFC8697], the ASSOCIATION
object could include other optional TLVs based on the association
types, Association
Types that provide 'information' "information" related to the association.
LSR: Label Switch Router. Switching Router
MPLS: Multiprotocol Label Switching. Switching
PAG: Policy Association Group. Group
PAT: Policy Association Type. Type
PCC: Path Computation Client; any client application requesting a
path computation to be performed by a Path Computation Element.
PCE: Path Computation Element; an entity (component, application, or
network node) that is capable of computing a network path or route
based on a network graph and applying computational constraints.
PCEP: Path Computation Element Communication Protocol. Protocol
3. Motivation
Paths computed using PCE can be subjected to various policies at both
the PCE and the PCC. For example, in a centralized traffic
engineering (TE) TE scenario,
network operators may instantiate LSPs and specify policies for
traffic accounting, path monitoring, telemetry, etc., for some LSPs
via the Stateful stateful PCE. Similarly, a PCC could request a user-specific
or service-specific policy to be applied at the PCE, such as a
constraints relaxation policy policy, to meet optimal QoS and resiliency. resiliency
levels.
PCEP speakers can use the generic mechanism of [RFC8697] to associate
a set of LSPs with a policy, without the need to know the details of
such a policy. This simplifies network operations and operations, avoids frequent
software upgrades, as well as and provides the ability to introduce new policies
more quickly.
PAG Y
{Service-Specific Policy
for constraint
Monitor LSP relaxation}
| |
| PAG X PCReq/PCRpt |
V {Monitor LSP} {PAG Y} V
+-----+ ----------------> +-----+
_ _ _ _ _ _| PCE | | | PCE |
| +-----+ | ----------> +-----+
| PCInitiate/PCUpd | | PCReq/PCRpt
|{PAG X} | | {PAG Y}
| | |
| .-----. | | .-----.
| ( ) | +----+ ( )
| .--( )--. | |PCC1|--.--( )--.
V ( ) | +----+ ( )
+---+ ( ) | ( )
|PCC|----( (G)MPLS network ) +----+ ( (G)MPLS network )
+---+ ( ) |PCC2|------( )
PAG X ( ) +----+ ( )
{Monitor '--( )--' '--( )--'
LSP} ( ) ( )
'-----' '-----'
Case 1: Policy requested by PCE Case 2: Policy requested by
and enforced by PCC PCC and enforced by
PCE
Figure 1: Sample use-cases Use Cases for carrying policies Carrying Policies over PCEP
3.1. Policy based Policy-Based Constraints
In the context of Policy-Enabled Path Computation Framework a policy-enabled path computation framework
[RFC5394], path computation policies may be applied at either a PCC
or PCC, a PCE PCE,
or both. A Label Switching Router (LSR) with a policy
enabled policy-enabled PCC
can receive
o a receive:
* A service request via signaling, including over a Network-Network
Interface (NNI) or User-Network Interface (UNI) reference point
o a point.
* A configuration request over a management interface to establish a
service
service.
The PCC may apply user-specific or service-specific policies to
decide how the path selection process should be constrained, constrained -- that
is, which constraints, diversities, optimization criterion, criteria, and
constraint relaxation
constraint-relaxation strategies should be applied in order for to increase the
likelihood that the service LSP(s) to have a likelihood to will be successfully established
and will provide the necessary QoS and resilience against network
failures. The user-specific or service-specific policies are applied
to the PCC and are then passed to the PCE along with the Path path
computation request, request in the form of constraints [RFC5394].
The PCEP speaker can use the generic mechanism as per [RFC8697] to
associate a set of LSPs with policies and its resulting path
computation constraints. user-specific or service-specific
policies. This would simplify the path computation message exchanges
in PCEP.
4. Overview
As per [RFC8697], LSPs are associated with other LSPs with which they
interact by adding them to a common association group. Grouping can
also be used to define the association between LSPs and the policies
associated to with them. 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. This document defines a new Association type,
Type called "Policy Association", of Association" with value 3 (early-allocated by IANA), based on the generic
ASSOCIATION object. This new Association type Type is also called "PAT", for "Policy
Association Type". Type" (PAT).
[RFC8697] specifies the mechanism for the capability advertisement of
the Association types Types supported by a PCEP speaker by defining a an
ASSOC-Type-List TLV to be carried within an OPEN object. This
capability exchange for the PAT MUST be done before using the policy
association. Thus Policy
Association. Thus, the PCEP speaker MUST include the PAT in the
ASSOC-Type-List TLV and MUST receive the same from the PCEP peer
before using the Policy Association Group (PAG) PAG in PCEP messages.
The Policy Association type Type (3) is operator-configured operator configured (as specified
in [RFC8697]), i.e. i.e., the association is created by the operator
manually on the PCEP peers peers, and an LSP belonging to this association
is conveyed via PCEP messages to the PCEP peer. There is no need to
convey an explicit Operator-configured Association Range, which could
only serve to artificially limit the available association Association IDs.
Thus, for the Policy Association type, Type, the Operator-configured
Association Range MUST NOT be set, set and MUST be ignored if received.
A PAG can have one or more LSPs. The association parameters
including association identifier, Association type Identifier, Policy Association Type (PAT), as
well as the association source Association Source IP address are manually configured by
the operator and are used to identify the PAG as described in
[RFC8697]. The Global Association Source and Extended Association ID
MAY also be included.
As per the processing rules specified in section Section 6.4 of [RFC8697], if
a PCEP speaker does not support this Policy Association type, Type, it
would return a PCErr PCEP error (PCErr) message with Error-Type 26
"Association Error" and Error-Value Error-value 1 "Association type is not
supported". The PAG and the policy MUST be configured on the PCEP
peers as per the operator-
configured operator-configured association procedures. All
further processing is as per
section Section 6.4 of [RFC8697]. If a PCE
speaker receives a PAG in a PCEP
message, message and the policy association Policy Association
information is not configured, it MUST return a PCErr message with
Error-Type 26 "Association Error" and Error-Value Error-value 4 "Association
unknown".
Associating a particular LSP to with multiple policy groups is allowed
from a protocol perspective, perspective; however, there is no assurance that the
PCEP speaker will be able to apply multiple policies. If a PCEP
speaker does not support handling of multiple policies for an LSP, it
MUST NOT add the LSP into the association group and MUST return a
PCErr with Error- Type Error-Type 26 (Association Error) "Association Error" and Error-value 7
(Cannot
"Cannot join the association group). group".
5. Policy Association Group
Association groups and their memberships are defined using the
ASSOCIATION object defined in [RFC8697]. Two object types for IPv4
and IPv6 are defined. The ASSOCIATION object includes "Association
type" indicating the type of the association group. This document
add
adds a new Association type Type, Policy Association Type (PAT).
PAG may carry optional TLVs including but not limited to -
o to:
POLICY-PARAMETERS-TLV:
Used to communicate opaque information useful to apply applying the
policy, described in Section 5.1.
o
VENDOR-INFORMATION-TLV:
Used to communicate arbitrary vendor
specific vendor-specific behavioral
information, described in [RFC7470].
5.1. Policy Parameters TLV
The POLICY-PARAMETERS-TLV is an optional TLV that can be carried in
The ASSOCIATION object (for PAT) to can carry an optional POLICY-
PARAMETERS-TLV with opaque information that is needed to apply the
policy at the PCEP peer. In some cases cases, to apply a PCE policy
successfully, it is required to also associate some policy parameters
that need to be evaluated. This TLV is used to carry those policy
parameters. The TLV could include one or more policy
related policy-related
parameters. The encoding format and the order MUST be known to the
PCEP peers, peers; this could be done during the configuration of the policy
(and its association parameters) for the PAG. The TLV format is as
per the format of the PCEP TLVs, as defined in [RFC5440], [RFC5440] and shown in
Figure 2. Only one POLICY-PARAMETERS-TLV can be carried carried, and only
the first occurrence is processed and any processed. Any others MUST be ignored.
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=48 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Policy Parameters //
| |
+---------------------------------------------------------------+
Figure 2: The POLICY-PARAMETERS-TLV format Format
The type of the POLICY-PARAMETERS-TLV type is 48 (early-allocated by IANA) 48, and it has a variable length.
The Value field is variable and padded to a 4-byte alignment; padding
is not included in the Length field. The PCEP peer implementation
needs to be aware of the encoding format, order, and meaning of the 'Policy Parameters'
policy parameters well in advance based on the policy. Note that
from the protocol point of view view, this data is opaque and can be used
to carry parameters in any format understood by the PCEP peers and
associated to with the policy. The exact use of this TLV is beyond the
scope of this document. Examples are included for illustration
purposes in Appendix A.
If the PCEP peer is unaware of the policy parameters associated with
the policy and it receives the POLICY-PARAMETERS-TLV, it MUST reject
the PCEP message and send a PCErr message with Error-Type 26
"Association Error" and Error-Value TBD3 Error-value 12 "Not expecting policy
parameters". Further, if at least one or more parameters parameter in the POLICY-
PARAMETERS-TLV received by the PCEP speaker are is considered as
unacceptable in the context of the associated policy (e.g., out of
range value, badly encoded value...), value, etc.), the PCEP speaker MUST reject
the PCEP message and send a PCErr message with Error-Type 26
"Association Error" and Error-Value TBD4 Error-value 13 "Unacceptable policy
parameters".
Note that, that the vendor-specific behavioral information is encoded in
VENDOR-INFORMATION-TLV
the VENDOR-INFORMATION-TLV, which can be used along with this TLV.
6. Implementation Status
[Note Security Considerations
The security considerations described in [RFC8697], [RFC8231],
[RFC5394], and [RFC5440] apply to the RFC Editor - remove extensions described in this section before publication,
document as
well well. In particular, a malicious PCEP speaker could be
spoofed and used as remove the reference to RFC 7942.]
This section records the status of known implementations of the
protocol defined an attack vector by this specification at the time of posting of this
Internet-Draft, and is based on a proposal creating spurious Policy
Associations as described in [RFC7942].
The description of implementations in this section is intended to
assist the IETF in its decision processes [RFC8697]. Further, as described in progressing drafts to
RFCs. Please note
[RFC8697], a spurious LSP can have policies that are inconsistent
with those of the listing of any individual implementation
here does not imply endorsement by the IETF. Furthermore, no effort
has been spent to verify the information presented here that was
supplied by IETF contributors. This is not intended as, and must not
be construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may
exist.
According to [RFC7942], "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature.
It is up to the individual working groups to use this information as
they see fit".
6.1. Cisco's Implementation
o Organization: Cisco Systems, Inc.
o Implementation: IOS-XR PCE and PCC.
o Description: The PCEP extension specified in this document is used
to convey traffic steering policies.
o Maturity Level: In shipping product.
o Coverage: Partial.
o Contact: mkoldych@cisco.com
7. Security Considerations
The security considerations described in [RFC8697], [RFC8231],
[RFC5394], and [RFC5440] apply to the extensions described in this
document as well. In particular, a malicious PCEP speaker could be
spoofed and used as an attack vector by creating spurious policy
associations as described in [RFC8697]. Further as described in
[RFC8697], a spurious LSP can have policies that are inconsistent
with those of the legitimate LSPs legitimate LSPs of the group and thus and, thus, cause
problems in the handling of the policy for the legitimate LSPs. It
should be noted that policy association Policy Association could provide an adversary
with the opportunity to eavesdrop on the relationship between the
LSPs. [RFC8697] suggest suggests that the implementations and operators to use
indirect values as a way to hide any sensitive business
relationships. Thus, securing the PCEP session using Transport Layer
Security (TLS) [RFC8253], as per the recommendations and best current
practices in BCP 195 [RFC7525], is RECOMMENDED.
Further, extra care needs to be taken by the implementation with
respect to the POLICY-PARAMETERS-TLV while decoding, verifying, and
applying these policy variables. This TLV parsing could be exploited
by an attacker and thus attacker; thus, extra care must be taken while configuring
policy association a
Policy Association that uses the POLICY-PARAMETERS-TLV and making
sure that the data is easy to parse and verify before use. Ensuring
agreement among all relevant PCEP peers as to the format and layout
of the policy parameters information is key for the correct operations.
Note that, that the parser for POLICY-PARAMETERS-TLV is particularly
sensitive since it is opque opaque to PCEP and can be used to convey data
with many different internal structure/formats. structures/formats. The choice of
decoder is dependent on the additional metadata associated with the policy and thus incur
policy; thus, additional risk of using a wrong decoder and getting
garbage results. Use results is incurred. Using standard and well-known policy
formats could help alleviate those risks.
8.
7. IANA Considerations
8.1. Association object
7.1. ASSOCIATION Object Type Indicators
This document defines a new Association type. The sub-registry Type in the subregistry
"ASSOCIATION Type Field" of the "Path Computation Element Protocol
(PCEP) Numbers" registry that was originally defined in [RFC8697]. IANA
is requested to confirm the early-allocated codepoint.
+=======+====================+===========+
| Value | Name | Reference |
+=======+====================+===========+
| 3 | Policy Association [This.I-D]
8.2. | RFC 9005 |
+-------+--------------------+-----------+
Table 1
7.2. PCEP TLV Type Indicators
The following TLV Type Indicator value is requested has been registered within the
"PCEP TLV Type Indicators" subregistry of the "Path Computation
Element Protocol (PCEP) Numbers" registry. IANA is requested to confirm the
early-allocated codepoint.
+=======+=======================+===========+
| Value | Description | Reference |
+=======+=======================+===========+
| 48 | POLICY-PARAMETERS-TLV [This.I-D]
8.3. | RFC 9005 |
+-------+-----------------------+-----------+
Table 2
7.3. PCEP Errors
This document defines new Error-Values Error-values for Error-type Error-Type 26 "Association
Error" defined in [RFC8697]. IANA is requested to allocate has allocated new error values
within the "PCEP- ERROR "PCEP-ERROR Object Error Types and Values" subregistry of
the PCEP Numbers "Path Computation Element Protocol (PCEP) Numbers" registry as
follows:
+============+===================+===================+===========+
| Error-Type | Meaning | Error-value | Reference |
+============+===================+===================+===========+
| 26 | Association [RFC8697] Error
TBD3: | | [RFC8697] |
+------------+-------------------+-------------------+-----------+
| | | 12: Not expecting [This.I-D] | RFC 9005 |
| | | policy parameters
TBD4: | |
+------------+-------------------+-------------------+-----------+
| | | 13: Unacceptable [This.I-D] | RFC 9005 |
| | | policy parameters
9. | |
+------------+-------------------+-------------------+-----------+
Table 3
8. Manageability Considerations
9.1.
8.1. Control of Function and Policy
An operator MUST be allowed to configure the policy associations Policy Associations at
PCEP peers and associate it them with the LSPs. They MAY also allow
configuration to related policy parameters, parameters and provide information on
the encoding format and order to parse the associated policy
parameters TLV.
9.2. POLICY-
PARAMETERS-TLV.
8.2. Information and Data Models
[RFC7420] describes the PCEP MIB; there are no new MIB Objects objects for
this document.
The PCEP YANG module is defined in [I-D.ietf-pce-pcep-yang]. [PCE-PCEP-YANG]. That module
supports associations as defined in [RFC8697] and thus [RFC8697]; thus, it supports the
Policy Association groups. Groups.
An implementation SHOULD allow the operator to view the PAG
configured. Further implementation SHOULD allow one to view
associations reported by each peer, peer and the current set of LSPs in the
PAG.
9.3.
8.3. Liveness Detection and Monitoring
Mechanisms
The mechanisms defined in this document do not imply any new liveness
detection and monitoring requirements in addition to those already
listed in [RFC5440], [RFC8231], [RFC5440] and [RFC8281].
9.4. Verify [RFC8231].
8.4. Verifying Correct Operations
Verifying the correct operation of a policy can be performed by
monitoring various parameters as described in [RFC5440] and
[RFC8231]. A PCEP implementation SHOULD provide information on
failed path computation because of appling due to applying policy and log error events,
e.g., parsing failure for policy parameters TLV.
9.5. a POLICY-PARAMETERS-TLV.
8.5. Requirements on Other Protocols
Mechanisms
The mechanisms defined in this document do not imply any new
requirements on other protocols.
9.6.
8.6. Impact on Network Operations
Mechanisms
The mechanisms defined in this document do not have any impact on
network operations in addition to those already listed in [RFC5440],
[RFC8231], and [RFC8281].
10. Acknowledgments
We would like to acknowledge and thank Santiago Alvarez, Zafar Ali,
Luis Tomotaki, Victor Lopez, Rob Shakir, and Clarence Filsfils for
working on earlier drafts with similar motivation.
A special thanks to the authors of [RFC8697], this document borrowed
some of the text from it. The authors would like to thank Aijun
Wang, Peng Shuping, and Gyan Mishra for their useful comments.
Thanks to Hari for shepherding this document. Thanks to Deborah
Brungard for providing comments and being the responsible AD for this
document.
Thanks to Nic Leymann for RTGDIR review.
Thanks to Benjamin Kaduk to those already listed in [RFC5440],
[RFC8231], and Murray Kucherawy for the comments during
IESG review.
11. [RFC8281].
9. References
11.1.
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009,
<https://www.rfc-editor.org/info/rfc5440>.
[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/info/rfc8174>.
[RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
Computation Element Communication Protocol (PCEP)
Extensions for Stateful PCE", RFC 8231,
DOI 10.17487/RFC8231, September 2017,
<https://www.rfc-editor.org/info/rfc8231>.
[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/info/rfc8253>.
[RFC8697] Minei, I., Crabbe, E., Sivabalan, S., Ananthakrishnan, H.,
Dhody, D., and Y. Tanaka, "Path Computation Element
Communication Protocol (PCEP) Extensions for Establishing
Relationships between Sets of Label Switched Paths
(LSPs)", RFC 8697, DOI 10.17487/RFC8697, January 2020,
<https://www.rfc-editor.org/info/rfc8697>.
11.2.
9.2. Informative References
[PCE-PCEP-YANG]
Dhody, D., Ed., Hardwick, J., Beeram, V., and J. Tantsura,
"A YANG Data Model for Path Computation Element
Communications Protocol (PCEP)", Work in Progress,
Internet-Draft, draft-ietf-pce-pcep-yang-16, 22 February
2021,
<https://tools.ietf.org/html/draft-ietf-pce-pcep-yang-16>.
[RFC4655] Farrel, A., Vasseur, J., J.-P., and J. Ash, "A Path
Computation Element (PCE)-Based Architecture", RFC 4655,
DOI 10.17487/RFC4655, August 2006,
<https://www.rfc-editor.org/info/rfc4655>.
[RFC5394] Bryskin, I., Papadimitriou, D., Berger, L., and J. Ash,
"Policy-Enabled Path Computation Framework", RFC 5394,
DOI 10.17487/RFC5394, December 2008,
<https://www.rfc-editor.org/info/rfc5394>.
[RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch,
"Network Time Protocol Version 4: Protocol and Algorithms
Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010,
<https://www.rfc-editor.org/info/rfc5905>.
[RFC5394] Bryskin, I., Papadimitriou, D., Berger, L., and J. Ash,
"Policy-Enabled Path Computation Framework", RFC 5394,
DOI 10.17487/RFC5394, December 2008,
<https://www.rfc-editor.org/info/rfc5394>.
[RFC7420] Koushik, A., Stephan, E., Zhao, Q., King, D., and J.
Hardwick, "Path Computation Element Communication Protocol
(PCEP) Management Information Base (MIB) Module",
RFC 7420, DOI 10.17487/RFC7420, December 2014,
<https://www.rfc-editor.org/info/rfc7420>.
[RFC7470] Zhang, F. and A. Farrel, "Conveying Vendor-Specific
Constraints in the Path Computation Element Communication
Protocol", RFC 7470, DOI 10.17487/RFC7470, March 2015,
<https://www.rfc-editor.org/info/rfc7470>.
[RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May
2015, <https://www.rfc-editor.org/info/rfc7525>.
[RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", BCP 205,
RFC 7942, DOI 10.17487/RFC7942, July 2016,
<https://www.rfc-editor.org/info/rfc7942>.
[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/info/rfc8281>.
[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/info/rfc8664>.
[I-D.ietf-pce-pcep-yang]
Dhody, D., Hardwick, J., Beeram, V., and J. Tantsura, "A
YANG Data Model for Path Computation Element
Communications Protocol (PCEP)", draft-ietf-pce-pcep-
yang-15 (work in progress), October 2020.
Appendix A. Example of Policy Parameters
An example could be a monitoring and telemetry policy P1 policy, P1, that is
dependent on a profile (GOLD/SILVER/BRONZE) as set by the operator.
The PCEP peers need to be aware of the policy P1 (and its associated
characteristics) in advance as well the fact that the policy
parameter will encode the profile of a type string in the POLICY-
PARAMETERS-TLV. As an example, LSP1 could encode the PAG with the
POLICY-PARAMETERS-TLV with a using the string "GOLD".
Another
The following is another example where the path computation at the
PCE could be dependent on when the LSP was configured at the PCC.
For such a policy policy, P2, the
time-stamp timestamp can be encoded in the POLICY-PARAMETERS-TLV POLICY-
PARAMETERS-TLV, and the exact encoding could be the 64-bit timestamp
format as defined in [RFC5905].
While the above example has a single field in the POLICY-PARAMETERS-
TLV, it is possible to include multiple fields, but the exact order,
encoding format format, and meanings need to be known in advance at the PCEP
peers.
Appendix B. Contributor Addresses
Following
Acknowledgments
We would like to acknowledge and thank Santiago Alvarez, Zafar Ali,
Luis Tomotaki, Victor Lopez, Rob Shakir, and Clarence Filsfils for
working on earlier draft versions with similar motivation.
Special thanks to the authors of [RFC8697]. This document borrowed
some of its text. The authors would like to thank Aijun Wang, Peng
Shuping, and Gyan Mishra for their useful comments.
Thanks to Hariharan Ananthakrishnan for shepherding this document.
Thanks to Deborah Brungard for providing comments and being the
responsible AD for this document.
Thanks to Nic Leymann for the RTGDIR review.
Thanks to Benjamin Kaduk and Murray Kucherawy for their comments
during the IESG review.
Contributors
The following individuals have contributed extensively:
Mahendra Singh Negi
RtBrick Inc
N-17L, 18th Cross Rd, HSR Layout
Bangalore, Karnataka
Bangalore 560102
Karnataka
India
EMail:
Email: mahend.ietf@gmail.com
Dhruv Dhody
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka
Bangalore 560066
Karnataka
India
EMail:
Email: dhruv.ietf@gmail.com
Following
The following individuals have contributed text that was
incorporated:
Qin Wu
Huawei Technologies
101 Software Avenue, Yuhua District
Nanjing, Jiangsu
Nanjing
Jiangsu, 210012
China
EMail:
Email: sunseawq@huawei.com
Xian Zhang
Huawei Technologies
Bantian, Longgang District
Shenzhen
518129
P.R.China
EMail:
China
Email: zhang.xian@huawei.com
Udayasree Palle
EMail:
Email: udayasreereddy@gmail.com
Mike Koldychev
Cisco Systems, Inc.
Canada
EMail:
Email: mkoldych@cisco.com
Authors' Addresses
Stephane Litkowski
Cisco Systems, Inc.
11 Rue Camille Desmoulins
Issy-les-Moulineaux
92130 Issy-les-Moulineaux
France
EMail:
Email: slitkows@cisco.com
Siva Sivabalan
Ciena
385 Terry Fox Drive
Kanata,
Kanata Ontario K2K 0L1
Canada
EMail:
Email: msiva282@gmail.com
Jeff Tantsura
Apstra, Inc.
EMail:
Juniper Networks
Email: jefftant.ietf@gmail.com
Jonathan Hardwick
Metaswitch Networks
100 Church Street
Enfield, Middlesex
UK
EMail:
33 Genotin Road
Enfield
United Kingdom
Email: Jonathan.Hardwick@metaswitch.com
Cheng Li
Huawei Technologies
Huawei Campus, No. 156 Beiqing Rd.
Beijing
100095
China
EMail:
Email: c.l@huawei.com
Additional contact information:
李呈
中国
100095
北京
华为北研所
华为技术有限公司