Internet DRAFT - draft-ietf-pce-stateful-path-protection
draft-ietf-pce-stateful-path-protection
PCE Working Group H. Ananthakrishnan
Internet-Draft Netflix
Intended status: Standards Track S. Sivabalan
Expires: March 28, 2020 Cisco
C. Barth
Juniper Networks
I. Minei
Google, Inc
M. Negi
Huawei Technologies
September 25, 2019
PCEP Extensions for Associating Working and Protection LSPs with
Stateful PCE
draft-ietf-pce-stateful-path-protection-11
Abstract
An active stateful Path Computation Element (PCE) is capable of
computing as well as controlling via Path Computation Element
Communication Protocol (PCEP) Multiprotocol Label Switching Traffic
Engineering (MPLS-TE) Label Switched Paths (LSPs). Furthermore, it
is also possible for an active stateful PCE to create, maintain, and
delete LSPs. This document defines the PCEP extension to associate
two or more LSPs to provide end-to-end path protection.
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
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Internet-Drafts are draft documents valid for a maximum of six months
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time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 28, 2020.
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Copyright Notice
Copyright (c) 2019 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
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. PCEP Extensions . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Path Protection Association Type . . . . . . . . . . . . 5
3.2. Path Protection Association TLV . . . . . . . . . . . . . 6
4. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.1. State Synchronization . . . . . . . . . . . . . . . . . . 7
4.2. PCC-Initiated LSPs . . . . . . . . . . . . . . . . . . . 7
4.3. PCE-Initiated LSPs . . . . . . . . . . . . . . . . . . . 7
4.4. Session Termination . . . . . . . . . . . . . . . . . . . 8
4.5. Error Handling . . . . . . . . . . . . . . . . . . . . . 8
5. Other Considerations . . . . . . . . . . . . . . . . . . . . 9
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
6.1. Association Type . . . . . . . . . . . . . . . . . . . . 10
6.2. Path Protection Association TLV . . . . . . . . . . . . . 10
6.3. PCEP Errors . . . . . . . . . . . . . . . . . . . . . . . 11
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12
8. Manageability Considerations . . . . . . . . . . . . . . . . 12
8.1. Control of Function and Policy . . . . . . . . . . . . . 12
8.2. Information and Data Models . . . . . . . . . . . . . . . 12
8.3. Liveness Detection and Monitoring . . . . . . . . . . . . 12
8.4. Verify Correct Operations . . . . . . . . . . . . . . . . 12
8.5. Requirements On Other Protocols . . . . . . . . . . . . . 12
8.6. Impact On Network Operations . . . . . . . . . . . . . . 13
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
10.1. Normative References . . . . . . . . . . . . . . . . . . 13
10.2. Informative References . . . . . . . . . . . . . . . . . 14
Appendix A. Contributor Addresses . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
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1. Introduction
[RFC5440] describes Path Computation Element Communication Protocol
for communication between a Path Computation Client (PCC) and a PCE
or between a pair of PCEs as per [RFC4655]. A PCE computes paths for
MPLS-TE Label Switched Paths (LSPs) based on various constraints and
optimization criteria.
Stateful PCE [RFC8231] specifies a set of extensions to PCEP to
enable stateful control of paths such as MPLS-TE LSPs between and
across PCEP sessions in compliance with [RFC4657]. It includes
mechanisms to affect LSP state synchronization between PCCs and PCEs,
delegation of control of LSPs to PCEs, and PCE control of timing and
sequence of path computations within and across PCEP sessions. The
focus is on a model where LSPs are configured on the PCC and control
over them is delegated to the Stateful PCE. Furthermore, [RFC8281]
specifies a mechanism to dynamically instantiate LSPs on a PCC based
on the requests from a stateful PCE or a controller using stateful
PCE.
Path protection [RFC4427] refers to a paradigm in which the working
LSP is protected by one or more protection LSP(s). When the working
LSP fails, protection LSP(s) is/are activated. When the working LSPs
are computed and controlled by the PCE, there is benefit in a mode of
operation where protection LSPs are also computed and controlled by
the same PCE. [RFC8051] describes applicability of path protection
in PCE deployments.
This document specifies a stateful PCEP extension to associate two or
more LSPs for the purpose of setting up path protection. The
extension defined in this document covers the following scenarios:
o A PCC initiates a protection LSP and retains the control of the
LSP. The PCC computes the path itself or makes a request for path
computation to a PCE. After the path setup, it reports the
information and state of the path to the PCE. This includes the
association group identifying the working and protection LSPs.
This is the passive stateful mode [RFC8051].
o A PCC initiates a protection LSP and delegates the control of the
LSP to a stateful PCE. During delegation the association group
identifying the working and protection LSPs is included. The PCE
computes the path for the protection LSP and updates the PCC with
the information about the path as long as it controls the LSP.
This is the active stateful mode [RFC8051].
o A protection LSP could be initiated by a stateful PCE, which
retains the control of the LSP. The PCE is responsible for
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computing the path of the LSP and updating to the PCC with the
information about the path. This is the PCE-Initiated mode
[RFC8281].
Note that a protection LSP can be established (signaled) before the
failure (in which case the LSP is said to be in standby mode
[RFC4427] or a Primary LSP [RFC4872]) or after failure of the
corresponding working LSP (known as a secondary LSP [RFC4872]).
Whether to establish it before or after failure is according to
operator choice or policy.
[I-D.ietf-pce-association-group] introduces a generic mechanism to
create a grouping of LSPs, which can then be used to define
associations between a set of LSPs. The mechanism is equally
applicable to stateful PCE (active and passive modes) and stateless
PCE.
This document specifies a PCEP extension to associate one working LSP
with one or more protection LSPs using the generic association
mechanism.
This document describes a PCEP extension to associate protection LSPs
by creating Path Protection Association Group (PPAG) and encoding
this association in PCEP messages for stateful PCEP sessions.
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 terminologies are used in this document:
ERO: Explicit Route Object.
LSP: Label Switched Path.
PCC: Path Computation Client.
PCE: Path Computation Element
PCEP: Path Computation Element Communication Protocol.
PPAG: Path Protection Association Group.
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TLV: Type, Length, and Value.
3. PCEP Extensions
3.1. Path Protection Association Type
As per [I-D.ietf-pce-association-group], LSPs are not associated by
listing the other LSPs with which they interact, but rather by making
them belong to an association groups. All LSPs join an association
group individually. The generic ASSOCIATION object is used to
associate two or more LSPs as specified in
[I-D.ietf-pce-association-group]. This document defines a new
Association type called "Path Protection Association Type" of value
TBD1 and a "Path Protection Association Group" (PPAG). A member LSP
of a PPAG can take the role of working or protection LSP. A PPAG can
have one working LSP and/or one or more protection LSPs. The source,
destination, Tunnel ID (as carried in LSP-IDENTIFIERS TLV [RFC8231],
with description as per [RFC3209]), and Protection Type (PT) (in Path
Protection Association TLV) of all LSPs within a PPAG MUST be the
same. As per [RFC3209], TE tunnel is used to associate a set of LSPs
during reroute or to spread a traffic trunk over multiple paths.
The format of the Association object used for PPAG is specified in
[I-D.ietf-pce-association-group].
[I-D.ietf-pce-association-group] specifies the mechanism for the
capability advertisement of the Association types supported by a PCEP
speaker by defining a ASSOC-Type-List TLV to be carried within an
OPEN object. This capability exchange for the Association type
described in this document (i.e. Path Protection Association Type)
MAY be done before using this association, i.e., the PCEP speaker MAY
include the Path Protection Association Type (TBD1) in the ASSOC-
Type-List TLV before using the PPAG in the PCEP messages.
This Association type is dynamic in nature and created by the PCC or
PCE for the LSPs belonging to the same TE tunnel (as described in
[RFC3209]) originating at the same head node and terminating at the
same destination. These associations are conveyed via PCEP messages
to the PCEP peer. As per [I-D.ietf-pce-association-group], the
association source is set to the local PCEP speaker address that
created the association, unless local policy dictates otherwise.
Operator-configured Association Range MUST NOT be set for this
Association type and MUST be ignored.
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3.2. Path Protection Association TLV
The Path Protection Association TLV is an optional TLV for use in the
ASSOCIATION Object with the Path Protection Association Type. The
Path Protection Association TLV MUST NOT be present more than once.
If it appears more than once, only the first occurrence is processed
and any others MUST be ignored.
The Path Protection Association TLV follows the PCEP TLV format of
[RFC5440].
The type (16 bits) of the TLV is TBD2. The length field (16 bit) has
a fixed value of 4.
The value comprises of a single field, the Path Protection
Association Flags (32 bits), where each bit represents a flag option.
The format of the Path Protection Association TLV (Figure 1) is as
follows:
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 = TBD2 | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PT | Unassigned Flags |S|P|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Path Protection Association TLV format
Path Protection Association Flags (32 bits) - The following flags are
currently defined -
Protecting (P): 1 bit - This bit is as defined in Section 14.1 of
[RFC4872] to indicate if the LSP is a working (0) or protection
(1) LSP.
Secondary (S): 1 bit - This bit is as defined in Section 14.1 of
[RFC4872] to indicate if the LSP is a primary (0) or secondary (1)
LSP. The S flag is ignored if the P flag is not set.
Protection Type (PT): 6 bits - This field is as defined in
Section 14.1 of [RFC4872] to indicate the LSP protection type in
use. Any type already defined or that could be defined in the
future for use in the RSVP-TE PROTECTION object is acceptable in
this TLV unless explicitly stated otherwise.
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Unassigned bits are considered reserved. They MUST be set to 0 on
transmission and MUST be ignored on receipt.
If the TLV is missing in PPAG ASSOCIATION object, it is considered
that the LSP is a working LSP (i.e. as if the P bit is unset).
4. Operation
An LSP is associated with other LSPs with which it interacts by
adding them to a common association group via the ASSOCIATION object.
All procedures and error-handling for the ASSOCIATION object is as
per [I-D.ietf-pce-association-group].
4.1. State Synchronization
During state synchronization, a PCC reports all the existing LSP
states as described in [RFC8231]. The association group membership
pertaining to an LSP is also reported as per
[I-D.ietf-pce-association-group]. This includes PPAGs.
4.2. PCC-Initiated LSPs
A PCC can associate a set of LSPs under its control for path
protection purposes. Similarly, the PCC can remove one or more LSPs
under its control from the corresponding PPAG. In both cases, the
PCC reports the change in association to PCE(s) via Path Computation
Report (PCRpt) messages. A PCC can also delegate the working and
protection LSPs to an active stateful PCE, where the PCE would
control the LSPs. The stateful PCE could update the paths and
attributes of the LSPs in the association group via Path Computation
Update (PCUpd) message. A PCE could also update the association to
the PCC via PCUpd message. These procedures are described in
[I-D.ietf-pce-association-group].
It is expected that both working and protection LSPs are delegated
together (and to the same PCE) to avoid any race conditions. Refer
to [I-D.litkowski-pce-state-sync] for the problem description.
4.3. PCE-Initiated LSPs
A PCE can create/update working and protection LSPs independently.
As specified in [I-D.ietf-pce-association-group], Association Groups
can be created by both the PCE and the PCC. Further, a PCE can
remove a protection LSP from a PPAG as specified in
[I-D.ietf-pce-association-group]. The PCE uses PCUpd or Path
Computation Initiate (PCInitiate) messages to communicate the
association information to the PCC.
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4.4. Session Termination
As per [I-D.ietf-pce-association-group] the association information
is cleared along with the LSP state information. When a PCEP session
is terminated, after expiry of State Timeout Interval at the PCC, the
LSP state associated with that PCEP session is reverted to operator-
defined default parameters or behaviors as per [RFC8231]. The same
procedure is also followed for the association information. On
session termination at the PCE, when the LSP state reported by PCC is
cleared, the association information is also cleared as per
[I-D.ietf-pce-association-group]. Where there are no LSPs in a
association group, the association is considered to be deleted.
4.5. Error Handling
As per the processing rules specified in section 6.4 of
[I-D.ietf-pce-association-group], if a PCEP speaker does not support
this Path Protection Association Type, it would return a PCErr
message with Error-Type 26 "Association Error" and Error-Value 1
"Association type is not supported".
All LSPs (working or protection) within a PPAG MUST belong to the
same TE Tunnel (as described in [RFC3209]) and have the same source
and destination. If a PCEP speaker attempts to add or update an LSP
to a PPAG and the Tunnel ID (as carried in LSP-IDENTIFIERS TLV
[RFC8231], with description as per [RFC3209]) or source or
destination of the LSP is different from the LSP(s) in the PPAG, the
PCEP speaker MUST send PCErr with Error-Type 26 (Association Error)
[I-D.ietf-pce-association-group] and Error-Value TBD3 (Tunnel ID or
End points mismatch for Path Protection Association). In case of
Path Protection, LSP-IDENTIFIERS TLV SHOULD be included for all LSPs
(including Segment Routing (SR) [I-D.ietf-pce-segment-routing]). If
the Protection Type (PT) (in Path Protection Association TLV) is
different from the LSPs in the PPAG, the PCEP speaker MUST send PCErr
with Error-Type 26 (Association Error)
[I-D.ietf-pce-association-group] and Error-Value 6 (Association
information mismatch) as per [I-D.ietf-pce-association-group].
When the PCEP peer does not support the protection type set in PPAG,
the PCEP peer MUST send PCErr with Error-Type 26 (Association Error)
[I-D.ietf-pce-association-group] and Error-Value TBD5 (Protection
type is not supported).
A given LSP MAY belong to more than one PPAG. If there is a conflict
between any of the two PPAGs, the PCEP peer MUST send PCErr with
Error-Type 26 (Association Error) [I-D.ietf-pce-association-group]
and Error-Value 6 (Association information mismatch) as per
[I-D.ietf-pce-association-group].
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When the protection type is set to 1+1 (i.e., protection type=0x08 or
0x10), there MUST be at maximum, only one working LSP and one
protection LSP within a PPAG. If a PCEP speaker attempts to add
another working/protection LSP, the PCEP peer MUST send PCErr with
Error-Type 26 (Association Error) [I-D.ietf-pce-association-group]
and Error-Value TBD4 (Attempt to add another working/protection LSP
for Path Protection Association).
When the protection type is set to 1:N (i.e., protection type=0x04),
there MUST be at maximum, only one working LSP and number of
protection LSPs MUST NOT be more than N within a PPAG. If a PCEP
speaker attempts to add another working/protection LSP, the PCEP peer
MUST send PCErr with Error-Type 26 (Association Error)
[I-D.ietf-pce-association-group] and Error-Value TBD4 (Attempt to add
another working/protection LSP for Path Protection Association).
During the make-before-break (MBB) procedure, two paths will briefly
coexist. The error handling related to number of LSPs allowed in a
PPAG MUST NOT be applied during MBB.
All processing as per [I-D.ietf-pce-association-group] continues to
apply.
5. Other Considerations
The working and protection LSPs are typically resource disjoint
(e.g., node, SRLG disjoint). This ensures that a single failure will
not affect both the working and protection LSPs. The disjoint
requirement for a group of LSPs is handled via another Association
type called "Disjointness Association", as described in
[I-D.ietf-pce-association-diversity]. The diversity requirements for
the protection LSP are also handled by including both ASSOCIATION
objects identifying both the protection association group and the
disjoint association group for the group of LSPs. The relationship
between the Synchronization VECtor (SVEC) object and the Disjointness
Association is described in section 5.3 of
[I-D.ietf-pce-association-diversity].
[RFC4872] introduces the concept and mechanisms to support the
association of one LSP to another LSP across different RSVP Traffic
Engineering (RSVP-TE) sessions using ASSOCIATION and PROTECTION
object. The information in the Path Protection Association TLV in
PCEP as received from the PCE is used to trigger the signaling of
working LSP and protection LSP, with the Path Protection Association
Flags mapped to the corresponding fields in the PROTECTION Object in
RSVP-TE.
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6. IANA Considerations
[Note to RFC Editor and IANA: Sections 3.1, 3.2, and 4.5 contain
"TBD1" through "TBD5" those should be replaced by the values that
IANA assigns.]
6.1. Association Type
This document defines a new Association type, originally defined in
[I-D.ietf-pce-association-group], for path protection. IANA is
requested to make the assignment of a new value for the sub-registry
"ASSOCIATION Type Field" (request to be created in
[I-D.ietf-pce-association-group]), as follows:
+----------------------+-------------------------+------------------+
| Association type | Association Name | Reference |
| Value | | |
+----------------------+-------------------------+------------------+
| TBD1 | Path Protection | This |
| | Association | document |
+----------------------+-------------------------+------------------+
6.2. Path Protection Association TLV
This document defines a new TLV for carrying additional information
of LSPs within a path protection association group. IANA is
requested to make the assignment of a new value for the existing
"PCEP TLV Type Indicators" registry as follows:
+---------------+-----------------------------------+---------------+
| TLV Type | TLV Name | Reference |
| Value | | |
+---------------+-----------------------------------+---------------+
| TBD2 | Path Protection Association Group | This document |
| | TLV | |
+---------------+-----------------------------------+---------------+
This document requests that a new sub-registry, named "Path
protection Association Group TLV Flag Field", is created within the
"Path Computation Element Protocol (PCEP) Numbers" registry to manage
the Flag field in the Path Protection Association Group TLV. New
values are to be assigned by Standards Action [RFC8126]. Each bit
should be tracked with the following qualities:
o Bit number (count from 0 as the most significant bit)
o Name flag
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o Reference
+------------+-----------------------+----------------+
| Bit Number | Name | Reference |
+------------+-----------------------+----------------+
| 31 | P - PROTECTION-LSP | This document |
| 30 | S - SECONDARY-LSP | This document |
| 6-29 | Unassigned | This document |
| 0-5 | Protection Type Flags | This document |
+------------+-----------------------+----------------+
Table 1: Path Protection Association TLV Flag Field
6.3. PCEP Errors
This document defines new Error-Values related to path protection
association for Error-type 26 "Association Error" defined in
[I-D.ietf-pce-association-group]. IANA is requested to allocate new
error values within the "PCEP-ERROR Object Error Types and Values"
sub-registry of the PCEP Numbers registry, as follows:
+---------+----------+-----------------+----------------------------+
| Error- | Error- | Meaning | Reference |
| type | value | | |
+---------+----------+-----------------+----------------------------+
| 26 | | Association | [I-D.ietf-pce-association- |
| | | Error | group] |
| | | | |
| | TBD3 | Tunnel ID or | This document |
| | | End points | |
| | | mismatch for | |
| | | Path Protection | |
| | | Association | |
| | TBD4 | Attempt to add | This document |
| | | another working | |
| | | /protection LSP | |
| | | for Path | |
| | | Protection | |
| | | Association | |
| | TBD5 | Protection type | This document |
| | | is not | |
| | | supported | |
+---------+----------+-----------------+----------------------------+
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7. Security Considerations
The security considerations described in [RFC8231], [RFC8281], and
[RFC5440] apply to the extensions described in this document as well.
Additional considerations related to associations where a malicious
PCEP speaker could be spoofed and could be used as an attack vector
by creating associations as described in
[I-D.ietf-pce-association-group]. Adding a spurious protection LSP
to the Path Protection Association group could give false sense of
network reliability, which leads to issues when the working LSP is
down and the protection LSP fails as well. 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.
8. Manageability Considerations
8.1. Control of Function and Policy
Mechanisms defined in this document do not imply any control or
policy requirements in addition to those already listed in [RFC5440],
[RFC8231], and [RFC8281].
8.2. Information and Data Models
[RFC7420] describes the PCEP MIB, there are no new MIB Objects for
this document.
The PCEP YANG module [I-D.ietf-pce-pcep-yang] supports associations.
8.3. 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], [RFC8231], and [RFC8281].
8.4. Verify Correct Operations
Mechanisms defined in this document do not imply any new operation
verification requirements in addition to those already listed in
[RFC5440], [RFC8231], and [RFC8281].
8.5. Requirements On Other Protocols
Mechanisms defined in this document do not imply any new requirements
on other protocols.
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8.6. Impact On Network Operations
Mechanisms defined in this document do not have any impact on network
operations in addition to those already listed in [RFC5440],
[RFC8231], and [RFC8281].
9. Acknowledgments
We would like to thank Jeff Tantsura, Xian Zhang and Greg Mirsky for
their contributions to this document.
Thanks to Ines Robles for the RTGDIR review.
Thanks to Pete Resnick for the GENART review.
Thanks to Donald Eastlake for the SECDIR review.
Thanks to Barry Leiba, Benjamin Kaduk, Eric Vyncke, and Roman Danyliw
for the IESG review.
10. References
10.1. 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>.
[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/info/rfc3209>.
[RFC4872] Lang, J., Ed., Rekhter, Y., Ed., and D. Papadimitriou,
Ed., "RSVP-TE Extensions in Support of End-to-End
Generalized Multi-Protocol Label Switching (GMPLS)
Recovery", RFC 4872, DOI 10.17487/RFC4872, May 2007,
<https://www.rfc-editor.org/info/rfc4872>.
[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>.
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Internet-Draft Stateful PCE LSP Path Protection September 2019
[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>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[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>.
[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>.
[I-D.ietf-pce-association-group]
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)", draft-ietf-pce-association-group-10 (work in
progress), August 2019.
10.2. Informative References
[RFC4427] Mannie, E., Ed. and D. Papadimitriou, Ed., "Recovery
(Protection and Restoration) Terminology for Generalized
Multi-Protocol Label Switching (GMPLS)", RFC 4427,
DOI 10.17487/RFC4427, March 2006,
<https://www.rfc-editor.org/info/rfc4427>.
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[RFC4655] Farrel, A., Vasseur, J., 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>.
[RFC4657] Ash, J., Ed. and J. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol Generic
Requirements", RFC 4657, DOI 10.17487/RFC4657, September
2006, <https://www.rfc-editor.org/info/rfc4657>.
[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>.
[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/info/rfc8051>.
[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-12 (work in progress), July 2019.
[I-D.ietf-pce-association-diversity]
Litkowski, S., Sivabalan, S., Barth, C., and M. Negi,
"Path Computation Element Communication Protocol (PCEP)
Extension for LSP Diversity Constraint Signaling", draft-
ietf-pce-association-diversity-10 (work in progress),
August 2019.
[I-D.ietf-pce-segment-routing]
Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
and J. Hardwick, "PCEP Extensions for Segment Routing",
draft-ietf-pce-segment-routing-16 (work in progress),
March 2019.
[I-D.litkowski-pce-state-sync]
Litkowski, S., Sivabalan, S., Li, C., and H. Zheng, "Inter
Stateful Path Computation Element (PCE) Communication
Procedures.", draft-litkowski-pce-state-sync-06 (work in
progress), July 2019.
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Appendix A. Contributor Addresses
Dhruv Dhody
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560066
India
EMail: dhruv.ietf@gmail.com
Raveendra Torvi
Juniper Networks
1194 N Mathilda Ave,
Sunnyvale, CA, 94086
USA
EMail: rtorvi@juniper.net
Edward Crabbe
Individual Contributor
EMail: edward.crabbe@gmail.com
Authors' Addresses
Hariharan Ananthakrishnan
Netflix
USA
Email: hari@netflix.com
Siva Sivabalan
Cisco
2000 Innovation Drive
Kananta, Ontaria K2K 3E8
Canada
Email: msiva@cisco.com
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Colby Barth
Juniper Networks
1194 N Mathilda Ave,
Sunnyvale, CA, 94086
USA
Email: cbarth@juniper.net
Ina Minei
Google, Inc
1600 Amphitheatre Parkway
Mountain View, CA, 94043
USA
Email: inaminei@google.com
Mahendra Singh Negi
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560066
India
Email: mahend.ietf@gmail.com
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