Internet DRAFT - draft-ietf-pce-association-group
draft-ietf-pce-association-group
PCE Working Group I. Minei
Internet-Draft Google, Inc.
Intended status: Standards Track E. Crabbe
Expires: February 2, 2020 Individual Contributor
S. Sivabalan
Cisco Systems, Inc.
H. Ananthakrishnan
Netflix
D. Dhody
Huawei
Y. Tanaka
NTT Communications Corporation
August 1, 2019
Path Computation Element Communication Protocol (PCEP) Extensions for
Establishing Relationships Between Sets of Label Switched Paths (LSPs)
draft-ietf-pce-association-group-10
Abstract
This document introduces a generic mechanism to create a grouping of
Label Switched Paths (LSPs) in the context of a Path Computation
Element (PCE). This grouping can then be used to define associations
between sets of LSPs or between a set of LSPs and a set of attributes
(such as configuration parameters or behaviours), and is equally
applicable to the stateful PCE (active and passive modes) as well as
the stateless PCE.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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 February 2, 2020.
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
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Architectural Overview . . . . . . . . . . . . . . . . . . . 4
3.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Relationship with the SVEC List . . . . . . . . . . . . . 5
3.3. Operation Overview . . . . . . . . . . . . . . . . . . . 5
3.4. Operator-configured Association Range . . . . . . . . . . 6
4. Discovery of Supported Association Types . . . . . . . . . . 7
4.1. ASSOC-Type-List TLV . . . . . . . . . . . . . . . . . . . 7
4.1.1. Procedure . . . . . . . . . . . . . . . . . . . . . . 8
5. Operator-configured Association Range TLV . . . . . . . . . . 8
5.1. Procedure . . . . . . . . . . . . . . . . . . . . . . . . 10
6. ASSOCIATION Object . . . . . . . . . . . . . . . . . . . . . 11
6.1. Object Definition . . . . . . . . . . . . . . . . . . . . 11
6.1.1. Global Association Source TLV . . . . . . . . . . . . 13
6.1.2. Extended Association ID TLV . . . . . . . . . . . . . 13
6.1.3. Association Source . . . . . . . . . . . . . . . . . 14
6.1.4. Unique Identification for an Association Group . . . 14
6.2. Relationship with the RSVP ASSOCIATION . . . . . . . . . 15
6.3. Object Encoding in PCEP messages . . . . . . . . . . . . 15
6.3.1. Stateful PCEP messages . . . . . . . . . . . . . . . 15
6.3.2. Request Message . . . . . . . . . . . . . . . . . . . 17
6.3.3. Reply Message . . . . . . . . . . . . . . . . . . . . 18
6.4. Processing Rules . . . . . . . . . . . . . . . . . . . . 19
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7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
7.1. PCEP Object . . . . . . . . . . . . . . . . . . . . . . . 21
7.2. PCEP TLV . . . . . . . . . . . . . . . . . . . . . . . . 22
7.3. Association Flags . . . . . . . . . . . . . . . . . . . . 22
7.4. Association Type . . . . . . . . . . . . . . . . . . . . 23
7.5. PCEP-Error Object . . . . . . . . . . . . . . . . . . . . 23
8. Security Considerations . . . . . . . . . . . . . . . . . . . 24
9. Manageability Considerations . . . . . . . . . . . . . . . . 24
9.1. Control of Function and Policy . . . . . . . . . . . . . 24
9.2. Information and Data Models . . . . . . . . . . . . . . . 24
9.3. Liveness Detection and Monitoring . . . . . . . . . . . . 25
9.4. Verify Correct Operations . . . . . . . . . . . . . . . . 25
9.5. Requirements on Other Protocols . . . . . . . . . . . . . 25
9.6. Impact on Network Operations . . . . . . . . . . . . . . 25
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 25
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 25
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 26
12.1. Normative References . . . . . . . . . . . . . . . . . . 26
12.2. Informative References . . . . . . . . . . . . . . . . . 27
Appendix A. Example for Operator-configured Association Range . 28
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29
1. Introduction
[RFC5440] describes the Path Computation Element (PCE) Communication
Protocol (PCEP). PCEP enables the communication between a Path
Computation Client (PCC) and a PCE, or between PCE and PCE, for the
purpose of computation of Multiprotocol Label Switching (MPLS) as
well as Generalized MPLS (GMPLS) Traffic Engineering Label Switched
Path (TE LSP) characteristics.
[RFC8231] specifies a set of extensions to PCEP to enable stateful
control of TE LSPs within and across PCEP sessions in compliance with
[RFC4657]. It includes mechanisms to effect LSP State
Synchronization between PCCs and PCEs, delegation of control over
LSPs to PCEs, and PCE control of timing and sequence of path
computations within and across PCEP sessions. The model of operation
where LSPs are initiated from the PCE is described in [RFC8281].
[RFC4872] defines the RSVP ASSOCIATION object, which was defined in
the context of GMPLS-controlled Label Switched Paths (LSPs) to be
used to associate recovery LSPs with the LSP they are protecting.
This object also has broader applicability as a mechanism to
associate RSVP state and [RFC6780] described how the ASSOCIATION
object can be more generally applied by defining the Extended
ASSOCIATION Object.
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This document introduces a generic mechanism to create a grouping of
LSPs. This grouping can then be used to define associations between
sets of LSPs or between a set of LSPs and a set of attributes (such
as configuration parameters or behaviours), and is equally applicable
to stateful PCE (active and passive modes) and stateless PCE. The
associations could be created dynamically and conveyed to a PCEP peer
within PCEP, or it could be configured manually by an operator on the
PCEP peers. Refer Section 3.3 for more details.
2. Terminology
This document uses the following terms defined in [RFC5440]: PCC,
PCE, PCEP Peer, Path Computation Request (PCReq), Path Computation
Reply (PCRep), and PCEP Error (PCErr).
This document uses the following terms defined in [RFC8051]: Stateful
PCE, Active Stateful PCE, Passive Stateful PCE, and Delegation.
This document uses the following terms defined in [RFC8231]: LSP
State Report (PCRpt), LSP Update Request (PCUpd), and State Timeout
Interval.
This document uses the following terms defined in [RFC8281]: PCE-
initiated LSP, and LSP Initiate Request (PCInitiate).
3. Architectural Overview
3.1. Motivation
Stateful PCE provides the ability to update existing LSPs and to
instantiate new ones. There are various situations where several
LSPs need to share common information. E.g., to support for PCE-
controlled make-before-break, an association between the original and
the re-optimized path is desired. Similarly, for end-to-end
protection, the association between working and protection LSPs is
required (see [I-D.ietf-pce-stateful-path-protection]). For diverse
paths, an association between a group of LSPs could be used (see
[I-D.ietf-pce-association-diversity]). Another use for the LSP
grouping is for applying a common set of configuration parameters or
behaviours to a set of LSPs.
For a stateless PCE, it might be useful to associate a path
computation request to an association group, thus enabling it to
associate a common set of policy, configuration parameters or
behaviours with the request.
Some associations could be created dynamically, such as association
between the working and protection LSPs of a tunnel, whereas some
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associations could be created by the operator manually, such as
policy-based association, where the LSP could join an operator-
configured existing association.
Rather than creating separate mechanisms for each use case, this
document defines a generic mechanism that can be reused as needed.
3.2. Relationship with the SVEC List
Note that, [RFC5440] defines a mechanism for the synchronization of a
set of path computation requests by using the SVEC (Synchronization
VECtor) object, that specifies the list of synchronized requests that
can either be dependent or independent. The SVEC object identifies
the relationship between the set of path computation requests,
identified by 'Request-ID-number' in RP (Request Parameters) object.
[RFC6007] further clarifies the use of the SVEC list for synchronized
path computations when computing dependent requests as well as
describes a number of usage scenarios for SVEC lists within single-
domain and multi-domain environments.
The motivation behind the association group defined in this document
and the SVEC object are quite different, though some use cases may
overlap. PCEP extensions that define a new association type should
clarify the relationship between the SVEC object and the association
type, if any.
3.3. Operation Overview
LSPs are associated with other LSPs with which they interact by
adding them to a common association group. Association groups as
defined in this document can be applied to LSPs originating at the
same head end or different head ends.
Some associations could be created dynamically by a PCEP speaker and
the associations (along with the set of LSPs) are conveyed to a PCEP
peer. Whereas some associations are configured by the operator on
the PCEP peers involved beforehand, a PCEP speaker then could ask for
a LSP to join the operator-configured association. Usage of dynamic
and configured association is usually dependent on the type of the
association.
For the operator-configured association, the association parameters
such as the association identifier, association type, as well as the
association source IP address, are manually configured by the
operator. In case of dynamic association, the association parameters
such as the association identifier, are allocated dynamically by the
PCEP speaker, the association source is set as local PCEP speaker
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address, unless local policy dictates otherwise, in which case
association source is set based on the local policy.
The dynamically created association can be reported to the PCEP peer
via the PCEP messages as per the stateful extensions. When the
operator-configured association is known to the PCEP peer beforehand,
a PCEP peer could ask for a LSP to join the operator-configured
association via the stateful PCEP messages.
The associations are properties of the LSP and thus could be stored
in the LSP state database. The dynamic association exists as long as
the LSP state exists. In case of PCEP session termination, the LSP
state clean-up MUST also take care of associations.
Multiple types of associations can exist, each with their own
association identifier space. The definition of the different
association types and their behaviours is outside the scope of this
document. The establishment and removal of the association
relationship can be done on a per LSP basis. An LSP may join
multiple association groups, of different or of the same association
type.
3.4. Operator-configured Association Range
Some association types are dynamic, some are operator-configured and
some could be both. For the association types that could be both
dynamic and operator-configured and use the same association source,
it is necessary to distinguish a range of association identifiers
that are marked for operator-configured associations to avoid any
association identifier clash within the scope of the association
source. This document assumes that these two ranges are configured.
A range of association identifiers for each Association type (and
Association Source) are kept for the operator-configured
associations. Dynamic associations MUST NOT use the association
identifier from this range.
This range as set at the PCEP speaker (PCC or PCE, as an association
source) needs to be communicated to a PCEP peer in the Open Message.
A new TLV is defined in this specification for this purpose
(Section 5). See Appendix A for an example.
Association identifier range for sources other than the PCEP speaker
(for example an NMS system) is not communicated in PCEP and the
procedure for operator-configured association range setting is
outside the scope of this document.
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4. Discovery of Supported Association Types
This section defines PCEP extensions so as to support the capability
advertisement of the association types supported by a PCEP speaker.
A new PCEP ASSOC-Type-List (Association Types list) TLV is defined.
The PCEP ASSOC-Type-List TLV is carried within an OPEN object. This
way, during PCEP session-setup phase, a PCEP speaker can advertise to
a PCEP peer the list of supported Association types.
4.1. ASSOC-Type-List TLV
The PCEP ASSOC-Type-List TLV is OPTIONAL. It MAY be carried within
an OPEN object sent by a PCEP speaker in an Open message to a PCEP
peer so as to indicate the list of supported Association types.
The PCEP ASSOC-Type-List TLV format is compliant with the PCEP TLV
format defined in [RFC5440]. That is, the TLV is composed of 2
octets for the type, 2 octets specifying the TLV length, and a Value
field. The Length field defines the length of the value portion in
octets. The TLV is padded to 4-octet alignment, and padding is not
included in the Length field (e.g., a 3-octet value would have a
length of three, but the total size of the TLV would be eight
octets).
The PCEP ASSOC-Type-List TLV has the following format:
TYPE: TBD
LENGTH: N * 2 (where N is the number of association types)
VALUE: list of 2-byte association type code points, identifying
the association types supported by the sender of the Open
message.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Assoc-type #1 | Assoc-type #2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Assoc-type #N | padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: The ASSOC-Type-List TLV format
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Assoc-type (2 bytes): Association type code point identifier. IANA
manages the "ASSOCIATION Type Field" code point registry (see
Section 7.4).
4.1.1. Procedure
An ASSOC-Type-List TLV within an OPEN object in an Open message is
included by a PCEP speaker in order to advertise a set of one or more
supported association types. The ASSOC-Type-List TLV MUST NOT appear
more than once in an OPEN object. If it appears more than once, the
PCEP session MUST be rejected with error type 1 and error value 1
(PCEP session establishment failure / Reception of an invalid Open
message). As specified in [RFC5440], a PCEP peer that does not
recognize the ASSOC-Type-List TLV will silently ignore it.
Association type (to be defined in other documents) can specify if
the association type advertisement is mandatory for it. Thus, the
ASSOC-Type-List TLV MUST be included if at least one mandatory
association type needs to be advertised and the ASSOC-Type-List TLV
MAY be included otherwise. For an association type that specifies
that the advertisement is mandatory, a missing Assoc-type in the
ASSOC-Type-List TLV (or missing ASSOC-Type-List TLV) is to be
interpreted as the association type is not supported by the PCEP
speaker.
The absence of the ASSOC-Type-List TLV in an OPEN object MUST be
interpreted as an absence of information on the list of supported
Association types (rather than the Association type is not
supported). In this case, the PCEP speaker could still use the
ASSOCIATION object: if the peer does not support the association, it
will react as per the procedure described in Section 6.4.
In case the use of the ASSOC-Type-List TLV is triggered by support
for a mandatory association type, then it is RECOMMENDED that the
PCEP implementation include all supported Association types
(including optional) to ease the operations of the PCEP peer.
5. Operator-configured Association Range TLV
This section defines PCEP extension to support the advertisement of
the Operator-configured Association Range used for an Association
type by the PCEP speaker (as an Association source).
A new PCEP OP-CONF-ASSOC-RANGE (Operator-configured Association
Range) TLV is defined. The PCEP OP-CONF-ASSOC-RANGE TLV is carried
within an OPEN object. This way, during PCEP session-setup phase, a
PCEP speaker can advertise to a PCEP peer the Operator-configured
Association Range for an association type.
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The PCEP OP-CONF-ASSOC-RANGE TLV is OPTIONAL. It MAY be carried
within an OPEN object sent by a PCEP speaker in an Open message to a
PCEP peer. The OP-CONF-ASSOC-RANGE TLV format is compliant with the
PCEP TLV format defined in [RFC5440]. That is, the TLV is composed
of 2 bytes for the type, 2 bytes specifying the TLV length, and a
Value field. The Length field defines the length of the value
portion in bytes.
The PCEP OP-CONF-ASSOC-RANGE TLV has the following format:
TYPE: 29 (Early allocation by IANA)
LENGTH: N * 8 (where N is the number of association types)
VALUE:
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Assoc-type #1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Start-Assoc-ID #1 | Range #1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Assoc-type #N |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Start-Assoc-ID #N | Range #N |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: The OP-CONF-ASSOC-RANGE TLV format
The Value portion includes the following fields, repeated for each
association type:
Reserved (2 bytes): This field MUST be set to 0 on transmission
and MUST be ignored on receipt.
Assoc-type (2 bytes): The association type (Section 7.4). The
association types are defined in separate documents.
Start-Assoc-ID (2 bytes): The start association identifier for the
Operator-configured Association Range for the particular
association type. The values 0 and 0xffff MUST NOT be used and on
receipt of these values in the TLV, the session is rejected with
error message sent (see Section 5.1).
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Range (2 bytes): The number of associations marked for the
Operator-configured Associations. The Range MUST be greater than
0, and it MUST be such that (Start-Assoc-ID + Range) do not cross
the association identifier range of 0xffff. In case this
condition is not satisfied, the session is rejected with error
message sent (see Section 5.1).
5.1. Procedure
A PCEP speaker MAY include an OP-CONF-ASSOC-RANGE TLV within an OPEN
object in an Open message sent to a PCEP peer in order to advertise
the Operator-configured Association Range for an association type.
The OP-CONF-ASSOC-RANGE TLV MUST NOT appear more than once in an OPEN
object. If it appears more than once, the PCEP session MUST be
rejected with error type 1 and error value 1 (PCEP session
establishment failure / Reception of an invalid Open message).
As specified in [RFC5440], a PCEP peer that does not recognize the
OP-CONF-ASSOC-RANGE TLV will silently ignore it.
The Operator-configured Association Range SHOULD be included for each
association type that could be both dynamic and operator-configured.
For association types that are only dynamic or only operator-
configured, this TLV MAY be skipped, in which case the full range of
association identifier is considered dynamic or operator-configured
respectively. Each association type (that are defined in separate
documents) can specify the default value for the operator-configured
association range for their respective association type.
The absence of the OP-CONF-ASSOC-RANGE TLV in an OPEN object MUST be
interpreted as an absence of explicit Operator-configured Association
Range at the PCEP peer. In this case, the default behavior as per
each association type applies. If the association source is not a
PCEP speaker, the default value for the operator-configured
association range is used for the association source.
If the Assoc-type is not recognized or supported by the PCEP speaker,
it MUST ignore that respective Start-Assoc-ID and Range. If the
Assoc-type is recognized/supported but the Start-Assoc-ID or Range
are set incorrectly, the PCEP session MUST be rejected with error
type 1 and error value 1 (PCEP session establishment failure /
Reception of an invalid Open message). The incorrect range include
the case when the (Start-Assoc-ID + Range) crosses the association
identifier range of 0xffff.
A given Assoc-type MAY appear more than once in the OP-CONF-ASSOC-
RANGE TLV in the case of a non-contiguous Operator-configured
Association Range. The PCEP speaker originating this TLV MUST NOT
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carry overlapping ranges for an association type. If a PCEP peer
receives overlapping ranges for an association type, it MUST consider
the Open message malformed and MUST reject the PCEP session with
error type 1 and error value 1 (PCEP session establishment failure /
Reception of an invalid Open message).
There may be cases where an operator-configured association was
configured with association parameters (such as association
identifier, association type and association source) at the local
PCEP speaker, and later the PCEP session gets established with the
association source and a new operator-configured range is learned
during session establishment. At this time, the local PCEP speaker
MUST remove any associations that are not in the new operator-
configured range (by disassociating any LSPs that are part of it (and
notifying this change to the PCEP peer)). If a PCEP speaker receives
an association for an operator-configured association and the
association identifier is not in the operator-configured association
range for the association type and association source, it MUST
generate an error (as described in Section 6.4).
6. ASSOCIATION Object
6.1. Object Definition
Association groups and their memberships are defined using a new
ASSOCIATION object.
ASSOCIATION Object-Class is 40 (Early allocation by IANA).
ASSOCIATION Object-Type is 1 for IPv4 and its format is shown in
Figure 3:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Flags |R|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Association type | Association ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Association Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Optional TLVs //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: The IPv4 ASSOCIATION Object format
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ASSOCIATION Object-Type is 2 for IPv6 and its format is shown in
Figure 4:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Flags |R|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Association type | Association ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| IPv6 Association Source |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Optional TLVs //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: The IPv6 ASSOCIATION Object format
Reserved (2-byte): MUST be set to 0 and ignored upon receipt.
Flags (2-byte): The following flags are currently defined:
R (Removal - 1 bit): when set, the requesting PCEP peer requires the
removal of an LSP from the association group. When unset, the
PCEP peer indicates that the LSP is added or retained as part of
the association group. This flag is used for the ASSOCIATION
object in the PCRpt and the PCUpd message, the flag is ignored in
other PCEP messages.
The unassigned flags MUST be set to zero on transmission and MUST be
ignored on receipt.
Association type (2-byte): the association type (Section 7.4). The
association types are defined in separate documents.
Association ID (2-byte): the identifier of the association group.
When combined with other association parameters, such as Association
Type and Association Source, this value uniquely identifies an
association group. The values 0xffff and 0x0 are reserved. The
value 0xffff is used to indicate all association groups and could be
used with R flag to indicate removal for all associations for the LSP
within the scope of association type and association source.
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Association Source: Contains a valid IPv4 address (4 bytes) if the
ASSOCIATION Object-Type is 1 or a valid IPv6 address (16 bytes) if
the ASSOCIATION Object-Type is 2. The address provides scoping for
the Association ID. See Section 6.1.3 for details.
Optional TLVs: The optional TLVs follow the PCEP TLV format of
[RFC5440]. This document defines two optional TLVs. Other documents
can define more TLVs in future.
6.1.1. Global Association Source TLV
The Global Association Source TLV is an optional TLV for use in the
Association Object. The meaning and the usage of Global Association
Source is as per Section 4 of [RFC6780].
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Global Association Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: The Global Association Source TLV format
Type: 30 (Early allocation by IANA).
Length: Fixed value of 4 bytes.
Global Association Source: as defined in Section 4 of [RFC6780].
6.1.2. Extended Association ID TLV
The Extended Association ID TLV is an optional TLV for use in the
Association Object. The meaning and the usage of Extended
Association ID is as per Section 4 of [RFC6780].
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Extended Association ID //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: The Extended Association ID TLV format
Type: 31 (Early allocation by IANA).
Length: variable.
Extended Association ID: as defined in Section 4 of [RFC6780].
6.1.3. Association Source
The Association Source field in the ASSOCIATION object is set to a
valid IP address to identify the node that originates the
association. In case of dynamic associations, the association source
is usually set as the local PCEP speaker address, unless local policy
dictates otherwise, in which case association source is set based on
the local policy. In case of PCE redundancy, local policy could set
the source as a virtual IP address which identifies all instances of
the PCE. In case of operator-configured association, the association
source is manually configured and it could be set as one of the PCEP
speakers, Network Management System (NMS), or any other valid IP
address that scopes the association identifier for the association
type.
6.1.4. Unique Identification for an Association Group
The combination of the mandatory fields Association type, Association
ID and Association Source in the ASSOCIATION object uniquely identify
the association group. If the optional TLVs - Global Association
Source or Extended Association ID are included, then they MUST be
included in combination with mandatory fields to uniquely identify
the association group. In this document, all these fields are
collectively called 'association parameters'. Note that the
ASSOCIATION object MAY include other optional TLVs (not defined in
this document) based on the association types, that provides
'information' related to the association type, this document uses the
term 'association information' for it.
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6.2. Relationship with the RSVP ASSOCIATION
The format of PCEP ASSOCIATION Object defined in this document is
aligned with the RSVP ASSOCIATION object ([RFC6780]). Various
Association types related to RSVP association are defined in
[RFC4872], [RFC4873], and [RFC7551]. The PCEP extensions that define
new association types, should clarify how the PCEP associations would
work with RSVP associations and vice-versa.
6.3. Object Encoding in PCEP messages
Message formats in this document are expressed using Reduced BNF
(RBNF) as used in [RFC5440] and defined in [RFC5511].
6.3.1. Stateful PCEP messages
The ASSOCIATION Object MAY be carried in the Path Computation Update
(PCUpd), Path Computation Report (PCRpt) and Path Computation
Initiate (PCInitiate) messages.
When carried in PCRpt message, it is used to report the association
group membership pertaining to a LSP to a stateful PCE. The PCRpt
message are used for both initial state synchronization operations
(Section 5.6 of [RFC8231]) as well as whenever the state of the LSP
changes. If the LSP belongs to an association group, then the
associations MUST be included during the state synchronization
operations.
The PCRpt message can also be used to remove an LSP from one or more
association groups by setting the R flag to 1 in the ASSOCIATION
object.
When an LSP is first reported to the PCE, the PCRpt message MUST
include all the association groups that it belongs to. Any
subsequent report message SHOULD include only the associations that
are being modified or removed.
The PCRpt message is defined in [RFC8231] and updated as below:
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<PCRpt Message> ::= <Common Header>
<state-report-list>
Where:
<state-report-list> ::= <state-report>[<state-report-list>]
<state-report> ::= [<SRP>]
<LSP>
[<association-list>]
<path>
Where:
<path>::= <intended-path>
[<actual-attribute-list><actual-path>]
<intended-attribute-list>
<association-list> ::= <ASSOCIATION> [<association-list>]
When an LSP is delegated to a stateful PCE, the stateful PCE can
create a new association group for this LSP, or associate it with one
or more existing association groups. This is done by including the
ASSOCIATION Object in a PCUpd message. A stateful PCE can also
remove a delegated LSP from one or more association groups by setting
the R flag to 1 in the ASSOCIATION object.
The PCUpd message SHOULD include the association groups that are
being modified or removed, there is no need to include associations
that remains unchanged.
The PCUpd message is defined in [RFC8231] and updated as below:
<PCUpd Message> ::= <Common Header>
<update-request-list>
Where:
<update-request-list> ::= <update-request>[<update-request-list>]
<update-request> ::= <SRP>
<LSP>
[<association-list>]
<path>
Where:
<path>::= <intended-path><intended-attribute-list>
<association-list> ::= <ASSOCIATION> [<association-list>]
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Unless a PCEP speaker wants to delete an association from an LSP or
make changes to the association, it does not need to carry the
ASSOCIATION object in future stateful messages.
A PCE initiating a new LSP can also include the association groups
that this LSP belongs to. This is done by including the ASSOCIATION
Object in a PCInitiate message. The PCInitiate message MUST include
all the association groups that it belongs to. The PCInitiate
message is defined in [RFC8281] and updated as below:
<PCInitiate Message> ::= <Common Header>
<PCE-initiated-lsp-list>
Where:
<PCE-initiated-lsp-list> ::= <PCE-initiated-lsp-request>
[<PCE-initiated-lsp-list>]
<PCE-initiated-lsp-request> ::= (<PCE-initiated-lsp-instantiation>|
<PCE-initiated-lsp-deletion>)
<PCE-initiated-lsp-instantiation> ::= <SRP>
<LSP>
[<END-POINTS>]
<ERO>
[<association-list>]
[<attribute-list>]
Where:
<association-list> ::= <ASSOCIATION> [<association-list>]
6.3.2. Request Message
In case of passive (stateful or stateless) PCE, the ASSOCIATION
Object is OPTIONAL and MAY be carried in the Path Computation Request
(PCReq) message.
When carried in a PCReq message, the ASSOCIATION Object is used to
associate the path computation request to an association group. The
association (and the other LSPs) should be known to the PCE
beforehand. These could be operator-configured or dynamically
learned before via stateful PCEP messages. The R flag in ASSOCIATION
object within PCReq message MUST be set to 0 while sending and
ignored on receipt.
The PCReq message is defined in [RFC5440] and updated in [RFC8231] ,
it is further updated below for association:
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<PCReq Message>::= <Common Header>
[<svec-list>]
<request-list>
Where:
<svec-list>::= <SVEC>[<svec-list>]
<request-list>::= <request>[<request-list>]
<request>::= <RP>
<END-POINTS>
[<LSP>]
[<LSPA>]
[<BANDWIDTH>]
[<metric-list>]
[<association-list>]
[<RRO>[<BANDWIDTH>]]
[<IRO>]
[<LOAD-BALANCING>]
Where:
<association-list> ::= <ASSOCIATION> [<association-list>]
Note that the LSP object MAY be present for the passive stateful PCE
mode.
6.3.3. Reply Message
In case of passive (stateful or stateless) PCE, the ASSOCIATION
Object is OPTIONAL and MAY be carried in the Path Computation Reply
(PCRep) message with the NO-PATH object. The ASSOCIATION object in
PCRep message indicates the association group that cause the PCE to
fail to find a path.
The PCRep message is defined in [RFC5440] and updated in [RFC8231] ,
it is further updated below for association:
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<PCRep Message> ::= <Common Header>
<response-list>
Where:
<response-list>::=<response>[<response-list>]
<response>::=<RP>
[<LSP>]
[<NO-PATH>]
[<association-list>]
[<attribute-list>]
[<path-list>]
Where:
<association-list> ::= <ASSOCIATION> [<association-list>]
Note that the LSP object MAY be present for the passive stateful PCE
mode.
6.4. Processing Rules
Association groups can be operator-configured on the necessary PCEP
speakers and the PCEP speakers can join the existing association
groups. In addition, a PCC or a PCE can create association groups
dynamically and the PCEP speaker can also report the associations to
its peer via PCEP messages. The operator-configured associations are
created via configurations (where all association parameters are
manually set) and exist until explicitly removed via configurations.
The PCEP speaker can add LSPs to these configured associations and
carry this via stateful PCEP messages. The dynamic associations are
created dynamically by the PCEP speaker (where all association
parameters are populated dynamically). The association group is
attached to the LSP state, and the association group exists till
there is at least one LSP as part of the association. As described
in Section 6.1.4, the association parameters are the combination of
Association type, Association ID and Association Source as well as
optional global source and extended association identifier, that
uniquely identifies an association group. The information related to
the association types encoded via the TLVs of a particular
association type (not described in this document) are the association
information (Section 6.1.4).
If a PCEP speaker does not recognize the ASSOCIATION object in the
stateful message, it will return a PCErr message with Error-Type
"Unknown Object" as described in [RFC5440]. In case of PCReq
message, the PCE would react based on the P flag as per [RFC5440].
If a PCEP speaker understands the ASSOCIATION object but does not
support the Association type, it MUST return a PCErr message with
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Error-Type 26 (Early allocation by IANA) "Association Error" and
Error-Value 1 "Association type is not supported". If any
association parameters are invalid in the ASSOCIATION object, the
PCEP speaker would consider this as malformed object and handle it as
malformed message [RFC5440]. On receiving a PCEP message with
ASSOCIATION, if a PCEP speaker finds that too many LSPs belong to the
association group, it MUST return a PCErr message with Error-Type 26
(Early allocation by IANA) "Association Error" and Error-Value 2 "Too
many LSPs in the association group". If a PCEP speaker cannot handle
a new association, it MUST return a PCErr message with Error-Type 26
(Early allocation by IANA) "Association Error" and Error-Value 3 "Too
many association groups". These numbers MAY be set by operator or
decided based on a local policy.
If a PCE peer is unwilling or unable to process the ASSOCIATION
object in the stateful message, it MUST return a PCErr message with
the Error-Type "Not supported object" and follow the relevant
procedures described in [RFC5440]. In case of PCReq message, the PCE
would react based on the P flag as per [RFC5440]. On receiving a
PCEP message with ASSOCIATION, if a PCEP speaker could not add the
LSP to the association group for any reason, it MUST return a PCErr
message with Error-Type 26 (Early allocation by IANA) "Association
Error" and Error-Value 7 "Cannot join the association group".
If a PCEP speaker receives an ASSOCIATION object for an operator-
configured association and the association identifier is not in the
operator-configured association range for the Association type and
Association Source, it MUST return a PCErr message with Error-Type 26
(Early allocation by IANA) "Association Error" and Error-Value 8
"Association identifier not in range".
If a PCEP speaker receives ASSOCIATION in PCReq message, and the
association is not known (association is not configured, or created
dynamically, or learned from a PCEP peer), it MUST return a PCErr
message with Error-Type 26 (Early allocation by IANA) "Association
Error" and Error-Value 4 "Association unknown".
If the association information (related to the association group as a
whole) received from the peer does not match with the local operator-
configured information, it MUST return a PCErr message with Error-
Type 26 (Early allocation by IANA) "Association Error" and Error-
Value 5 "Operator-configured association information mismatch". On
receiving association information (related to the association group
as a whole) that does not match with the association information
previously received about the same association from a peer, it MUST
return a PCErr message with Error-Type 26 (Early allocation by IANA)
"Association Error" and Error-Value 6 "Association information
mismatch". Note that information related to each LSP within the
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association as part of the association information TLVs could be
different.
If a PCEP speaker receives an ASSOCIATION object with the R bit set
for removal, and the association group (identified by association
parameters) is not known, it MUST return a PCErr message with Error-
Type 26 (Early allocation by IANA) "Association Error" and Error-
Value 4 "Association unknown".
The dynamic associations are cleared along with the LSP state
information as per the [RFC8231]. When a PCEP session is terminated,
after expiry of State Timeout Interval at PCC, the LSP state
associated with that PCEP session is reverted to operator-defined
default parameters or behaviours. Same procedure is also followed
for the association groups. On session termination at the PCE, when
the LSP state reported by PCC is cleared, the association groups are
also cleared. When there are no LSPs in an association group, the
association is considered to be empty and thus deleted.
In case the LSP is delegated to another PCE on session failure, the
associations (and association information) set by the PCE remains
intact, unless updated by the new PCE that takes over.
Upon LSP delegation revocation, the PCC MAY clear the association
created by the PCE, but in order to avoid traffic loss, it SHOULD
perform this in a make-before-break fashion (same as [RFC8231]).
7. IANA Considerations
IANA maintains the "Path Computation Element Protocol (PCEP) Numbers"
registry at <http://www.iana.org/assignments/pcep>.
7.1. PCEP Object
The "PCEP Numbers" registry contains a subregistry "PCEP Objects".
IANA is requested to confirm the early allocation of the following
code point in the PCEP Objects registry.
Object-Class Value Name Reference
40 (Early allocation by Association [This.I-D]
IANA)
Object-Type
0: Reserved
1: IPv4
2: IPv6
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7.2. PCEP TLV
IANA is requested to confirm the early allocation of the following
code point in the "PCEP TLV Type Indicators" registry.
Value Meaning Reference
29 (Early Operator-configured [This.I-D]
allocation by Association Range
IANA)
30 (Early Global Association Source [This.I-D]
allocation by
IANA)
31 (Early Extended Association ID [This.I-D]
allocation by
IANA)
IANA is requested to fix the meaning for value 31 in the above
registry to 'Extended Association ID', it is currently mentioned as
'Extended Association Id'.
IANA is also requested to make a new assignment for the existing
"PCEP TLV Type Indicators" registry as follows:
Value Meaning Reference
TBD ASSOC-Type-List [This.I-D]
7.3. Association Flags
This document requests IANA to create a subregistry of the "PCEP
Numbers" for the bits carried in the Flags field of the ASSOCIATION
object. The subregistry is called "ASSOCIATION Flags Field". New
values are assigned by Standards Action [RFC8126]. Each bit should
be tracked with the following qualities:
o Bit number (counting from bit 0 as the most significant bit)
o Capability description
o Defining RFC
Bit Description Reference
15 R (Removal) [This.I-D]
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7.4. Association Type
This document requests IANA to create a subregistry of the "PCEP
Numbers" for the Association Type field of the the ASSOCIATION
object. The subregistry is called "ASSOCIATION Type Field". New
values are to be assigned by Standards Action [RFC8126]. Each value
should be tracked with the following qualities:
o Type
o Name
o Reference
There are no association types specified in this document, future
documents should request the assignment of association types from
this subregistry.
7.5. PCEP-Error Object
IANA is requested to confirm the early allocation of the following
code points within the "PCEP-ERROR Object Error Types and Values"
sub-registry of the "PCEP Numbers" registry, as follows:
Error-Type Meaning
26 Association Error [This.I-D]
(early Error-value=0:
alloc by Unassigned
IANA) Error-value=1:
Association type is not supported
Error-value=2:
Too many LSPs in the association group
Error-value=3:
Too many association groups
Error-value=4:
Association unknown
Error-value=5:
Operator-configured association
information mismatch
Error-value=6:
Association information mismatch
Error-value=7:
Cannot join the association group
Error-value=8:
Association identifier not in range
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8. Security Considerations
The security considerations described in [RFC8231] and [RFC5440]
apply to the extensions described in this document as well.
Additional considerations related to a malicious PCEP speaker are
introduced, as associations could be spoofed and could be used as an
attack vector. An attacker could attempt to create too many
associations in an attempt to load the PCEP peer. The PCEP peer
responds with PCErr as described in Section 6.4. An attacker could
impact LSP operations by creating bogus associations. Further,
association groups could provides an adversary with the opportunity
to eavesdrop on the relationship between the LSPs. Thus securing the
PCEP session using Transport Layer Security (TLS) [RFC8253], as per
the recommendations and best current practices in [RFC7525], is
RECOMMENDED.
Much of the information carried in the ASSOCIATION object, as per
this document is not extra sensitive. It often reflects information
that can also be derived from the LSP Database, but association
provides a much easier grouping of related LSPs and messages.
Implementations and operator can and should use indirect values in
ASSOCIATION as a way to hide any sensitive business relationships.
9. Manageability Considerations
All manageability requirements and considerations listed in [RFC5440]
and [RFC8231] apply to PCEP protocol extensions defined in this
document. In addition, requirements and considerations listed in
this section apply.
9.1. Control of Function and Policy
A PCE or PCC implementation MUST allow operator-configured
associations and SHOULD allow setting of the operator-configured
association range (Section 3.4) as described in this document.
9.2. Information and Data Models
The PCEP YANG module is defined in [I-D.ietf-pce-pcep-yang]. In
future, this YANG module should be extended or augmented to provide
the following additional information relating to association groups.
An implementation SHOULD allow the operator to view the associations
configured or created dynamically. Further implementation SHOULD
allow to view associations reported by each peer, and the current set
of LSPs in the association.
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It might also be useful to find out how many associations for each
association type currently exist and to know how many free
association identifiers are available for a particular association
type and source.
9.3. 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].
9.4. Verify Correct Operations
Mechanisms defined in this document do not imply any new operation
verification requirements in addition to those already listed in
[RFC5440] and [RFC8231].
9.5. Requirements on Other Protocols
Mechanisms defined in this document do not imply any new requirements
on other protocols.
9.6. Impact on Network Operations
Mechanisms defined in [RFC5440] and [RFC8231] also apply to PCEP
extensions defined in this document.
10. Acknowledgments
We would like to thank Yuji Kamite and Joshua George for their
contributions to this document. Also thanks to Venugopal Reddy,
Cyril Margaria, Rakesh Gandhi, Mike Koldychev, and Adrian Farrel for
their useful comments.
We would like to thank Julien Meuric for shepherding this document
and providing comments with text suggestions.
Thanks to Stig Venaas for the RTGDIR review comments.
Thanks to Alvaro Retana, Mirja Kuhlewind, Martin Vigoureux, Barry
Leiba, Eric Vyncke, Suresh Krishnan, and Benjamin Kaduk for the IESG
comments.
11. Contributors
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Stephane Litkowski
Orange
Email: stephane.litkowski@orange.com
Xian Zhang
Huawei Technologies
F3-1-B RnD Center, Huawei Base
Bantian, Longgang District
Shenzhen 518129
China
Email: zhang.xian@huawei.com
Mustapha Aissaoui
Nokia
Email: mustapha.aissaoui@nokia.com
12. References
12.1. 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>.
[RFC5511] Farrel, A., "Routing Backus-Naur Form (RBNF): A Syntax
Used to Form Encoding Rules in Various Routing Protocol
Specifications", RFC 5511, DOI 10.17487/RFC5511, April
2009, <https://www.rfc-editor.org/info/rfc5511>.
[RFC6780] Berger, L., Le Faucheur, F., and A. Narayanan, "RSVP
ASSOCIATION Object Extensions", RFC 6780,
DOI 10.17487/RFC6780, October 2012,
<https://www.rfc-editor.org/info/rfc6780>.
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[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>.
[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>.
[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>.
[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>.
12.2. Informative References
[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>.
[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>.
[RFC4873] Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel,
"GMPLS Segment Recovery", RFC 4873, DOI 10.17487/RFC4873,
May 2007, <https://www.rfc-editor.org/info/rfc4873>.
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[RFC6007] Nishioka, I. and D. King, "Use of the Synchronization
VECtor (SVEC) List for Synchronized Dependent Path
Computations", RFC 6007, DOI 10.17487/RFC6007, September
2010, <https://www.rfc-editor.org/info/rfc6007>.
[RFC7551] Zhang, F., Ed., Jing, R., and R. Gandhi, Ed., "RSVP-TE
Extensions for Associated Bidirectional Label Switched
Paths (LSPs)", RFC 7551, DOI 10.17487/RFC7551, May 2015,
<https://www.rfc-editor.org/info/rfc7551>.
[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>.
[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-stateful-path-protection]
Ananthakrishnan, H., Sivabalan, S., Barth, C., Minei, I.,
and M. Negi, "PCEP Extensions for Associating Working and
Protection LSPs with Stateful PCE", draft-ietf-pce-
stateful-path-protection-07 (work in progress), June 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-08 (work in progress), July
2019.
Appendix A. Example for Operator-configured Association Range
Consider an association type T1 (which allows both dynamic and
operator-configured association with a default range of <0x1000,
0xffff>). Consider that, because of need of the network, the PCE
needs to create more dynamic associations and would like to change
the association range to <0xbffe, 0xffff> instead. During PCEP
session establishment the PCE would advertise the new range, the PCC
could skip advertising as the default values are used. If a PCC is
creating a dynamic association (with PCC as association source) it
needs to pick a free association identifier for type T1 in the range
of <0x1, 0x0fff> whereas if a PCE is creating a dynamic association
(with PCE as association source) it needs to pick a free association
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identifier from the range <0x1, 0xbffd>. Similarly if an operator-
configured association is manually configured with the PCC as
association source, it should be from the range <0x1000, 0xffff>
whereas if the PCE is association source, it should be from <0xbffe,
0xffff>. In case the association source is not a PCEP peer (for
example an NMS system), then the default range of <0x1000, 0xffff> is
considered.
Authors' Addresses
Ina Minei
Google, Inc.
1600 Amphitheatre Parkway
Mountain View, CA 94043
US
Email: inaminei@google.com
Edward Crabbe
Individual Contributor
Email: edward.crabbe@gmail.com
Siva Sivabalan
Cisco Systems, Inc.
170 West Tasman Dr.
San Jose, CA 95134
US
Email: msiva@cisco.com
Hariharan Ananthakrishnan
Netflix
Email: hari@netflix.com
Dhruv Dhody
Huawei
Divyashree Techno Park, Whitefield
Bangalore, KA 560066
India
Email: dhruv.ietf@gmail.com
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Yosuke Tanaka
NTT Communications Corporation
Granpark Tower 3-4-1 Shibaura, Minato-ku
Tokyo 108-8118
Japan
Email: yosuke.tanaka@ntt.com
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