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IETF RFC 8779
Last modified on Wednesday, July 22nd, 2020
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Internet Engineering Task Force (IETF) C. Margaria, Ed.
Request for Comments: 8779 Juniper
Category: Standards Track O. Gonzalez de Dios, Ed.
ISSN: 2070-1721 Telefonica Investigacion y Desarrollo
F. Zhang, Ed.
Huawei Technologies
July 2020
Path Computation Element Communication Protocol (PCEP) Extensions for
GMPLS
 Abstract
A Path Computation Element (PCE) provides path computation functions
for Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS)
networks. Additional requirements for GMPLS are identified in RFC
7025.
This memo provides extensions to the Path Computation Element
Communication Protocol (PCEP) for the support of the GMPLS control
plane to address those requirements.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for 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 this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/RFC 8779.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction
1.1. Terminology
1.2. PCEP Requirements for GMPLS
1.3. Requirements Applicability
1.3.1. Requirements on the Path Computation Request
1.3.2. Requirements on the Path Computation Response
1.4. Existing Support and Limitations for GMPLS in Base PCEP
Objects
2. PCEP Objects and Extensions
2.1. GMPLS Capability Advertisement
2.1.1. GMPLS Computation TLV in the Existing PCE Discovery
Protocol
2.1.2. OPEN Object Extension GMPLS-CAPABILITY TLV
2.2. RP Object Extension
2.3. BANDWIDTH Object Extensions
2.4. LOAD-BALANCING Object Extensions
2.5. END-POINTS Object Extensions
2.5.1. Generalized Endpoint Object Type
2.5.2. END-POINTS TLV Extensions
2.6. IRO Extension
2.7. XRO Extension
2.8. LSPA Extensions
2.9. NO-PATH Object Extension
2.9.1. Extensions to NO-PATH-VECTOR TLV
3. Additional Error-Types and Error-Values Defined
4. Manageability Considerations
4.1. Control of Function through Configuration and Policy
4.2. Information and Data Models
4.3. Liveness Detection and Monitoring
4.4. Verifying Correct Operation
4.5. Requirements on Other Protocols and Functional Components
4.6. Impact on Network Operation
5. IANA Considerations
5.1. PCEP Objects
5.2. Endpoint Type Field in the Generalized END-POINTS Object
5.3. New PCEP TLVs
5.4. RP Object Flag Field
5.5. New PCEP Error Codes
5.6. New Bits in NO-PATH-VECTOR TLV
5.7. New Subobject for the Include Route Object
5.8. New Subobject for the Exclude Route Object
5.9. New GMPLS-CAPABILITY TLV Flag Field
6. Security Considerations
7. References
7.1. Normative References
7.2. Informative References
Appendix A. LOAD-BALANCING Usage for SDH Virtual Concatenation
Acknowledgments
Contributors
Authors' Addresses
1. Introduction
Although the PCE architecture and framework for both MPLS and GMPLS
networks are defined in [RFC 4655], most pre-existing PCEP RFCs, such
as [RFC 5440], [RFC 5521], [RFC 5541], and [RFC 5520], are focused on
MPLS networks and do not cover the wide range of GMPLS networks.
This document complements these RFCs by addressing the extensions
required for GMPLS applications and routing requests, for example,
for Optical Transport Networks (OTNs) and Wavelength Switched Optical
Networks (WSONs).
The functional requirements to be addressed by the PCEP extensions to
support these applications are fully described in [RFC 7025] and
[RFC 7449].
1.1. Terminology
This document uses terminologies from the PCE architecture document
[RFC 4655]; the PCEP documents including [RFC 5440], [RFC 5521],
[RFC 5541], [RFC 5520], [RFC 7025], and [RFC 7449]; and the GMPLS
documents such as [RFC 3471], [RFC 3473], and so on. Note that the
reader is expected to be familiar with these documents. The
following abbreviations are used in this document:
ERO: Explicit Route Object
IRO: Include Route Object
L2SC: Layer 2 Switch Capable [RFC 3471]
LSC: Lambda Switch Capable [RFC 3471]
LSP: Label Switched Path
LSPA: LSP Attribute
MEF: Metro Ethernet Forum
MT: Multiplier [RFC 4328] [RFC 4606]
NCC: Number of Contiguous Components [RFC 4606]
NVC: Number of Virtual Components [RFC 4328] [RFC 4606]
ODU: Optical Data Unit [G.709-v3]
OTN: Optical Transport Network [G.709-v3]
P2MP: Point-to-Multipoint
PCC: Path Computation Client
PCRep: Path Computation Reply [RFC 5440]
PCReq: Path Computation Request [RFC 5440]
RCC: Requested Contiguous Concatenation [RFC 4606]
RRO: Record Route Object
RSVP-TE: Resource Reservation Protocol - Traffic Engineering
SDH: Synchronous Digital Hierarchy
SONET: Synchronous Optical Network
SRLG: Shared Risk Link Group
SSON: Spectrum-Switched Optical Network
TDM: Time-Division Multiplex Capable [RFC 3471]
TE-LSP: Traffic Engineered LSP
XRO: Exclude Route Object
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 [RFC 2119] [RFC 8174] when, and only when, they appear in all
capitals, as shown here.
1.2. PCEP Requirements for GMPLS
[RFC 7025] describes the set of PCEP requirements that support GMPLS
TE-LSPs. This document assumes a significant familiarity with
[RFC 7025] and existing PCEP extensions. As a short overview, those
requirements can be broken down into the following categories.
* Which data flow is switched by the LSP: a combination of a
switching type (for instance, L2SC or TDM), an LSP encoding type
(e.g., Ethernet, SONET/SDH), and sometimes the signal type (e.g.,
in case of a TDM or an LSC switching capability).
* Data-flow-specific traffic parameters, which are technology
specific. For instance, in SDH/SONET and OTN networks [G.709-v3],
the concatenation type and the concatenation number have an
influence on the switched data and on which link it can be
supported.
* Support for asymmetric bandwidth requests.
* Support for unnumbered interface identifiers, as defined in
[RFC 3477].
* Label information and technology-specific label(s) such as
wavelength labels as defined in [RFC 6205]. A PCC should also be
able to specify a label restriction similar to the one supported
by RSVP-TE in [RFC 3473].
* Ability to indicate the requested granularity for the path ERO:
node, link, or label. This is to allow the use of the explicit
label control feature of RSVP-TE.
The requirements of [RFC 7025] apply to several objects conveyed by
PCEP; this is described in Section 1.3. Some of the requirements of
[RFC 7025] are already supported in existing documents, as described
in Section 1.4.
This document describes a set of PCEP extensions, including new
object types, TLVs, encodings, error codes, and procedures, in order
to fulfill the aforementioned requirements not covered in existing
RFCs.
1.3. Requirements Applicability
This section follows the organization of [RFC 7025], Section 3 and
indicates, for each requirement, the affected piece of information
carried by PCEP and its scope.
1.3.1. Requirements on the Path Computation Request
(1) Switching capability/type: As described in [RFC 3471], this
piece of information is used with the encoding type and signal
type to fully describe the switching technology and data
carried by the TE-LSP. This is applicable to the TE-LSP itself
and also to the TE-LSP endpoint (carried in the END-POINTS
object for MPLS networks in [RFC 5440]) when considering
multiple network layers. Inter-layer path computation
requirements are addressed in [RFC 8282], which focuses on the
TE-LSP itself but does not address the TE-LSP endpoints.
(2) Encoding type: See (1).
(3) Signal type: See (1).
(4) Concatenation type: This parameter and the concatenation number
(see (5)) are specific to some TDM (SDH and ODU) switching
technologies. They MUST be described together and are used to
derive the requested resource allocation for the TE-LSP. It is
scoped to the TE-LSP and is related to the BANDWIDTH object
[RFC 5440] in MPLS networks. See concatenation information in
[RFC 4606] and [RFC 4328].
(5) Concatenation number: See (4).
(6) Technology-specific label(s): As described in [RFC 3471], the
GMPLS labels are specific to each switching technology. They
can be specified on each link and also on the TE-LSP endpoints,
in WSON networks, for instance, as described in [RFC 6163]. The
label restriction can apply to endpoints, and on each hop, the
related PCEP objects are END-POINTS, IRO, XRO, and RRO.
(7) End-to-End (E2E) path protection type: As defined in [RFC 4872],
this is applicable to the TE-LSP. In MPLS networks, the
related PCEP object is LSPA (carrying local protection
information).
(8) Administrative group: As defined in [RFC 3630], this information
is already carried in the LSPA object.
(9) Link protection type: As defined in [RFC 4872], this is
applicable to the TE-LSP and is carried in association with the
E2E path protection type.
(10) Support for unnumbered interfaces: As defined in [RFC 3477].
Its scope and related objects are the same as labels.
(11) Support for asymmetric bandwidth requests: As defined in
[RFC 6387], the scope is similar to (4).
(12) Support for explicit label control during the path computation:
This affects the TE-LSP and the amount of information returned
in the ERO.
(13) Support of label restrictions in the requests/responses: This
is described in (6).
1.3.2. Requirements on the Path Computation Response
(1) Path computation with concatenation: This is related to the Path
Computation request requirement (4). In addition, there is a
specific type of concatenation, called virtual concatenation,
that allows different routes to be used between the endpoints.
It is similar to the semantic and scope of the LOAD-BALANCING in
MPLS networks.
(2) Label constraint: The PCE should be able to include labels in
the path returned to the PCC; the related object is the ERO
object.
(3) Roles of the routes: As defined in [RFC 4872], this is applicable
to the TE-LSP and is carried in association with the E2E path
protection type.
1.4. Existing Support and Limitations for GMPLS in Base PCEP Objects
The support provided by specifications in [RFC 8282] and [RFC 5440] for
the requirements listed in [RFC 7025] is summarized in Tables 1 and 2.
In some cases, the support may not be complete, as noted, and
additional support needs to be provided as indicated in this
specification.
+======+====================================+===============+
| Req. | Name | Support |
+======+====================================+===============+
| 1 | Switching capability/type | SWITCH-LAYER |
| | | (RFC 8282) |
+------+------------------------------------+---------------+
| 2 | Encoding type | SWITCH-LAYER |
| | | (RFC 8282) |
+------+------------------------------------+---------------+
| 3 | Signal type | SWITCH-LAYER |
| | | (RFC 8282) |
+------+------------------------------------+---------------+
| 4 | Concatenation type | No |
+------+------------------------------------+---------------+
| 5 | Concatenation number | No |
+------+------------------------------------+---------------+
| 6 | Technology-specific label | (Partial) ERO |
| | | (RFC 5440) |
+------+------------------------------------+---------------+
| 7 | End-to-End (E2E) path protection | No |
| | type | |
+------+------------------------------------+---------------+
| 8 | Administrative group | LSPA (RFC |
| | | 5440) |
+------+------------------------------------+---------------+
| 9 | Link protection type | No |
+------+------------------------------------+---------------+
| 10 | Support for unnumbered interfaces | (Partial) ERO |
| | | (RFC 5440) |
+------+------------------------------------+---------------+
| 11 | Support for asymmetric bandwidth | No |
| | requests | |
+------+------------------------------------+---------------+
| 12 | Support for explicit label control | No |
| | during the path computation | |
+------+------------------------------------+---------------+
| 13 | Support of label restrictions in | No |
| | the requests/responses | |
+------+------------------------------------+---------------+
Table 1: Requirements Support per RFC 7025, Section 3.1
+======+=====================================+=========+
| Req. | Name | Support |
+======+=====================================+=========+
| 1 | Path computation with concatenation | No |
+------+-------------------------------------+---------+
| 2 | Label constraint | No |
+------+-------------------------------------+---------+
| 3 | Roles of the routes | No |
+------+-------------------------------------+---------+
Table 2: Requirements Support per RFC 7025, Section 3.2
Per Section 1.3, PCEP (as described in [RFC 5440], [RFC 5521], and
[RFC 8282]) supports the following objects, included in requests and
responses, that are related to the described requirements.
From [RFC 5440]:
END-POINTS: related to requirements 1, 2, 3, 6, 10, and 13. The
object only supports numbered endpoints. The context specifies
whether they are node identifiers or numbered interfaces.
BANDWIDTH: related to requirements 4, 5, and 11. The data rate
is encoded in the BANDWIDTH object (as an IEEE 32-bit float).
[RFC 5440] does not include the ability to convey an encoding
proper to all GMPLS-controlled networks.
ERO: related to requirements 6, 10, 12, and 13. The ERO content
is defined in RSVP in [RFC 3209], [RFC 3473], [RFC 3477], and
[RFC 7570] and already supports all of the requirements.
LSPA: related to requirements 7, 8, and 9. Requirement 8
(Administrative group) is already supported.
From [RFC 5521]:
XRO:
- This object allows excluding (strict or not) resources and is
related to requirements 6, 10, and 13. It also includes the
requested diversity (node, link, or SRLG).
- When the F bit is set, the request indicates that the existing
path has failed, and the resources present in the RRO can be
reused.
From [RFC 8282]:
SWITCH-LAYER: addresses requirements 1, 2, and 3 for the TE-LSP
and indicates which layer(s) should be considered. The object
can be used to represent the RSVP-TE Generalized Label Request.
It does not address the endpoints case of requirements 1, 2,
and 3.
REQ-ADAP-CAP: indicates the adaptation capabilities requested; it
can also be used for the endpoints in case of mono-layer
computation.
The gaps in functional coverage of the base PCEP objects are:
* The BANDWIDTH and LOAD-BALANCING objects do not describe the
details of the traffic request (requirements 4 and 5, for example,
NVC and multiplier) in the context of GMPLS networks, for
instance, in TDM or OTN networks.
* The END-POINTS object does not allow specifying an unnumbered
interface, nor potential label restrictions on the interface
(requirements 6, 10, and 13). Those parameters are of interest in
case of switching constraints.
* The IROs/XROs do not allow the inclusion/exclusion of labels
(requirements 6, 10, and 13).
* Base attributes do not allow expressing the requested link
protection level and/or the end-to-end protection attributes.
As defined later in this document, the PCEP extensions that cover the
gaps are:
* Two new object types are defined for the BANDWIDTH object
(Generalized bandwidth and Generalized bandwidth of an existing
TE-LSP for which a reoptimization is requested).
* A new object type is defined for the LOAD-BALANCING object
(Generalized Load Balancing).
* A new object type is defined for the END-POINTS object
(Generalized Endpoint).
* A new TLV is added to the Open message for capability negotiation.
* A new TLV is added to the LSPA object.
* The Label subobject is now allowed in the IRO and XRO objects.
* In order to indicate the routing granularity used in the response,
a new flag is added in the RP object.
2. PCEP Objects and Extensions
This section describes the necessary PCEP objects and extensions.
The PCReq and PCRep messages are defined in [RFC 5440]. This document
does not change the existing grammar.
2.1. GMPLS Capability Advertisement
2.1.1. GMPLS Computation TLV in the Existing PCE Discovery Protocol
IGP-based PCE Discovery (PCED) is defined in [RFC 5088] and [RFC 5089]
for the OSPF and IS-IS protocols. Those documents have defined bit 0
in the PCE-CAP-FLAGS Sub-TLV of the PCED TLV as "Path computation
with GMPLS link constraints". This capability is optional and can be
used to detect GMPLS-capable PCEs. PCEs that set the bit to indicate
support of GMPLS path computation MUST follow the procedures in
Section 2.1.2 to further qualify the level of support during PCEP
session establishment.
2.1.2. OPEN Object Extension GMPLS-CAPABILITY TLV
In addition to the IGP advertisement, a PCEP speaker MUST be able to
discover the other peer GMPLS capabilities during the Open message
exchange. This capability is also useful to avoid misconfigurations.
This document defines a GMPLS-CAPABILITY TLV for use in the OPEN
object to negotiate the GMPLS capability. The inclusion of this TLV
in the Open message indicates that the PCEP speaker supports the PCEP
extensions defined in the document. A PCEP speaker that is able to
support the GMPLS extensions defined in this document MUST include
the GMPLS-CAPABILITY TLV in the Open message. If one of the PCEP
peers does not include the GMPLS-CAPABILITY TLV in the Open message,
the peers MUST NOT make use of the objects and TLVs defined in this
document.
If the PCEP speaker supports the extensions of this specification but
did not advertise the GMPLS-CAPABILITY capability, upon receipt of a
message from the PCE including an extension defined in this document,
it MUST generate a PCEP Error (PCErr) with Error-Type=10 (Reception
of an invalid object) and Error-value=31 (Missing GMPLS-CAPABILITY
TLV), and it SHOULD terminate the PCEP session.
As documented in Section 5.3 ("New PCEP TLVs"), IANA has allocated
value 45 (GMPLS-CAPABILITY) from the "PCEP TLV Type Indicators" sub-
registry. The format for the GMPLS-CAPABILITY TLV is shown in the
following figure.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=45 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
No flags are defined in this document; they are reserved for future
use. Unassigned flags MUST be set to zero on transmission and MUST
be ignored on receipt.
2.2. RP Object Extension
Explicit Label Control (ELC) is a procedure supported by RSVP-TE,
where the outgoing labels are encoded in the ERO. As a consequence,
the PCE can provide such labels directly in the path ERO. Depending
on the policies or switching layer, it might be necessary for the PCC
to use explicit label control or explicit link ids; thus, it needs to
indicate in the PCReq which granularity it is expecting in the ERO.
This corresponds to requirement 12 in Section 3.1 of [RFC 7025]. The
possible granularities can be node, link, or label. The
granularities are interdependent, in the sense that link granularity
implies the presence of node information in the ERO; similarly, a
label granularity implies that the ERO contains node, link, and label
information.
A new 2-bit Routing Granularity (RG) flag (bits 15-16) is defined in
the RP object. The values are defined as follows:
0: reserved
1: node
2: link
3: label
The RG flag in the RP object indicates the requested route
granularity. The PCE SHOULD follow this granularity and MAY return a
NO-PATH if the requested granularity cannot be provided. The PCE MAY
return any granularity on the route based on its policy. The PCC can
decide if the ERO is acceptable based on its content.
If a PCE honored the requested routing granularity for a request, it
MUST indicate the selected routing granularity in the RP object
included in the response. Otherwise, the PCE MUST use the reserved
RG to leave the check of the ERO to the PCC. The RG flag is backward
compatible with [RFC 5440]: the value sent by an implementation (PCC
or PCE) not supporting it will indicate a reserved value.
2.3. BANDWIDTH Object Extensions
Per [RFC 5440], the object carrying the requested size for the TE-LSP
is the BANDWIDTH object. Object types 1 and 2 defined in [RFC 5440]
do not provide enough information to describe the TE-LSP bandwidth in
GMPLS networks. The BANDWIDTH object encoding has to be extended to
allow the object to express the bandwidth as described in [RFC 7025].
RSVP-TE extensions for GMPLS provide a set of encodings that allow
such representation in an unambiguous way; this is encoded in the
RSVP-TE Traffic Specification (TSpec) and Flow Specification
(FlowSpec) objects. This document extends the BANDWIDTH object with
new object types reusing the RSVP-TE encoding.
The following possibilities are supported by the extended encoding:
* Asymmetric bandwidth (different bandwidth in forward and reverse
direction), as described in [RFC 6387].
* GMPLS (SDH/SONET, G.709, ATM, MEF, etc.) parameters.
This corresponds to requirements 3, 4, 5, and 11 in Section 3.1 of
[RFC 7025].
This document defines two object types for the BANDWIDTH object:
3: Generalized bandwidth
4: Generalized bandwidth of an existing TE-LSP for which a
reoptimization is requested
The definitions below apply for object types 3 and 4. The body 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth Spec Length | Rev. Bandwidth Spec Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bw Spec Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Generalized Bandwidth ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Reverse Generalized Bandwidth (optional) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Optional TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
BANDWIDTH object types 3 and 4 have a variable length. The 16-bit
Bandwidth Spec Length field indicates the length of the Generalized
Bandwidth field. The Bandwidth Spec Length MUST be strictly greater
than 0. The 16-bit Reverse Bandwidth Spec Length field indicates the
length of the Reverse Generalized Bandwidth field. The Reverse
Bandwidth Spec Length MAY be equal to 0.
The Bw Spec Type field determines which type of bandwidth is
represented by the object.
The Bw Spec Type corresponds to the RSVP-TE SENDER_TSPEC (Object
Class 12) C-Types.
The encoding of the Generalized Bandwidth and Reverse Generalized
Bandwidth fields is the same as the traffic parameters carried in
RSVP-TE; they can be found in the following references. Note that
the RSVP-TE traffic specification MAY also include TLVs that are
different from the PCEP TLVs (e.g., the TLVs defined in [RFC 6003]).
+==============+===========+===========+
| Bw Spec Type | Name | Reference |
+==============+===========+===========+
| 2 | Intserv | [RFC 2210] |
+--------------+-----------+-----------+
| 4 | SONET/SDH | [RFC 4606] |
+--------------+-----------+-----------+
| 5 | G.709 | [RFC 4328] |
+--------------+-----------+-----------+
| 6 | Ethernet | [RFC 6003] |
+--------------+-----------+-----------+
| 7 | OTN-TDM | [RFC 7139] |
+--------------+-----------+-----------+
| 8 | SSON | [RFC 7792] |
+--------------+-----------+-----------+
Table 3: Generalized Bandwidth and
Reverse Generalized Bandwidth Field
Encoding
When a PCC requests a bidirectional path with symmetric bandwidth, it
SHOULD only specify the Generalized Bandwidth field and set the
Reverse Bandwidth Spec Length to 0. When a PCC needs to request a
bidirectional path with asymmetric bandwidth, it SHOULD specify the
different bandwidth in the forward and reverse directions with
Generalized Bandwidth and Reverse Generalized Bandwidth fields.
The procedure described in [RFC 5440] for the PCRep is unchanged: a
PCE MAY include the BANDWIDTH objects in the response to indicate the
BANDWIDTH of the path.
As specified in [RFC 5440], in the case of the reoptimization of a TE-
LSP, the bandwidth of the existing TE-LSP MUST also be included in
addition to the requested bandwidth if and only if the two values
differ. The object type 4 MAY be used instead of the previously
specified object type 2 to indicate the existing TE-LSP bandwidth,
which was originally specified with object type 3. A PCC that
requested a path with a BANDWIDTH object of object type 1 MUST use
object type 2 to represent the existing TE-LSP bandwidth.
Optional TLVs MAY be included within the object body to specify more
specific bandwidth requirements. No TLVs for object types 3 and 4
are defined by this document.
2.4. LOAD-BALANCING Object Extensions
The LOAD-BALANCING object [RFC 5440] is used to request a set of at
most Max-LSP TE-LSPs having in total the bandwidth specified in
BANDWIDTH, with each TE-LSP having at least a specified minimum
bandwidth. The LOAD-BALANCING object follows the bandwidth encoding
of the BANDWIDTH object; thus, the existing definition from [RFC 5440]
does not describe enough details for the bandwidth specification
expected by GMPLS.
Similar to the BANDWIDTH object, a new object type is defined to
allow a PCC to represent the bandwidth types supported by GMPLS
networks.
This document defines object type 2 (Generalized Load Balancing) for
the LOAD-BALANCING object. The Generalized Load Balancing object
type has a variable length.
The format of the Generalized Load Balancing object type 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth Spec Length | Reverse Bandwidth Spec Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bw Spec Type | Max-LSP | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Min Bandwidth Spec |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Min Reverse Bandwidth Spec (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Optional TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Bandwidth Spec Length (16 bits): the total length of the Min
Bandwidth Spec field. The length MUST be strictly greater than 0.
Reverse Bandwidth Spec Length (16 bits): the total length of the Min
Reverse Bandwidth Spec field. It MAY be equal to 0.
Bw Spec Type (8 bits): the bandwidth specification type; it
corresponds to RSVP-TE SENDER_TSPEC (Object Class 12) C-Types.
Max-LSP (8 bits): the maximum number of TE-LSPs in the set.
Min Bandwidth Spec (variable): specifies the minimum bandwidth
specification of each element of the TE-LSP set.
Min Reverse Bandwidth Spec (variable): specifies the minimum reverse
bandwidth specification of each element of the TE-LSP set.
The encoding of the Min Bandwidth Spec and Min Reverse Bandwidth Spec
fields is the same as in the RSVP-TE SENDER_TSPEC object; it can be
found in Table 3 in Section 2.3 of this document.
When a PCC requests a bidirectional path with symmetric bandwidth
while specifying load-balancing constraints, it SHOULD specify the
Min Bandwidth Spec field and set the Reverse Bandwidth Spec Length to
0. When a PCC needs to request a bidirectional path with asymmetric
bandwidth while specifying load-balancing constraints, it MUST
specify the different bandwidth in forward and reverse directions
through Min Bandwidth Spec and Min Reverse Bandwidth Spec fields.
Optional TLVs MAY be included within the object body to specify more
specific bandwidth requirements. No TLVs for the Generalized Load
Balancing object type are defined by this document.
The semantic of the LOAD-BALANCING object is not changed. If a PCC
requests the computation of a set of TE-LSPs with at most N TE-LSPs
so that it can carry Generalized bandwidth X, each TE-LSP must at
least transport bandwidth B; it inserts a BANDWIDTH object specifying
X as the required bandwidth and a LOAD-BALANCING object with the Max-
LSP and Min Bandwidth Spec fields set to N and B, respectively. When
the BANDWIDTH and Min Bandwidth Spec can be summarized as scalars,
the sum of the bandwidth for all TE-LSPs in the set is greater than
X. The mapping of the X over N path with (at least) bandwidth B is
technology and possibly node specific. Each standard definition of
the transport technology is defining those mappings and are not
repeated in this document. A simplified example for SDH is described
in Appendix A.
In all other cases, including technologies based on statistical
multiplexing (e.g., InterServ and Ethernet), the exact bandwidth
management (e.g., the Ethernet's Excessive Rate) is left to the PCE's
policies, according to the operator's configuration. If required,
further documents may introduce a new mechanism to finely express
complex load-balancing policies within PCEP.
The BANDWIDTH and LOAD-BALANCING Bw Spec Type can be different
depending on the architecture of the endpoint node. When the PCE is
not able to handle those two Bw Spec Types, it MUST return a NO-PATH
with the bit "LOAD-BALANCING could not be performed with the
bandwidth constraints" set in the NO-PATH-VECTOR TLV.
2.5. END-POINTS Object Extensions
The END-POINTS object is used in a PCEP request message to specify
the source and the destination of the path for which a path
computation is requested. Per [RFC 5440], the source IP address and
the destination IP address are used to identify those. A new object
type is defined to address the following possibilities:
* Different source and destination endpoint types.
* Label restrictions on the endpoint.
* Specification of unnumbered endpoints type as seen in GMPLS
networks.
The object encoding is described in the following sections.
In path computation within a GMPLS context, the endpoints can:
* Be unnumbered as described in [RFC 3477].
* Have labels associated to them, specifying a set of constraints on
the allocation of labels.
* Have different switching capabilities.
The IPv4 and IPv6 endpoints are used to represent the source and
destination IP addresses. The scope of the IP address (node or
numbered link) is not explicitly stated. It is also possible to
request a path between a numbered link and an unnumbered link, or a
P2MP path between different types of endpoints.
This document defines object type 5 (Generalized Endpoint) for the
END-POINTS object. This new type also supports the specification of
constraints on the endpoint label to be used. The PCE might know the
interface restrictions, but this is not a requirement. This
corresponds to requirements 6 and 10 in Section 3.1 of [RFC 7025].
2.5.1. Generalized Endpoint Object Type
The Generalized Endpoint object type format consists of a body and a
list of TLVs scoped to this object. The TLVs give the details of the
endpoints and are described in Section 2.5.2. For each endpoint
type, a different grammar is defined. The TLVs defined to describe
an endpoint are:
1. IPV4-ADDRESS
2. IPV6-ADDRESS
3. UNNUMBERED-ENDPOINT
4. LABEL-REQUEST
5. LABEL-SET
The LABEL-SET TLV is used to restrict or suggest the label allocation
in the PCE. This TLV expresses the set of restrictions that may
apply to signaling. Label restriction support can be an explicit or
a suggested value (LABEL-SET describing one label, with the L bit
cleared or set, respectively), mandatory range restrictions (LABEL-
SET with the L bit cleared), and optional range restriction (LABEL-
SET with the L bit set). Endpoints label restriction may not be part
of the RRO or IRO. They can be included when following [RFC 4003] in
signaling for the egress endpoint, but ingress endpoint properties
can be local to the PCC and not signaled. To support this case, the
LABEL-SET allows indication of which labels are used in case of
reoptimization. The label range restrictions are valid in GMPLS-
controlled networks, depending on either the PCC policy or the
switching technology used, for instance, on a given Ethernet or ODU
equipment having limited hardware capabilities restricting the label
range. Label set restriction also applies to WSON networks where the
optical senders and receivers are limited in their frequency
tunability ranges, consequently restricting the possible label ranges
on the interface in GMPLS. The END-POINTS object with the
Generalized Endpoint object type is encoded 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Endpoint Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Reserved bits SHOULD be set to 0 when a message is sent and ignored
when the message is received.
The values for the Endpoint Type field are defined as follows:
+=========+======================================+
| Value | Type |
+=========+======================================+
| 0 | Point-to-Point |
+---------+--------------------------------------+
| 1 | Point-to-Multipoint with leaf type 1 |
+---------+--------------------------------------+
| 2 | Point-to-Multipoint with leaf type 2 |
+---------+--------------------------------------+
| 3 | Point-to-Multipoint with leaf type 3 |
+---------+--------------------------------------+
| 4 | Point-to-Multipoint with leaf type 4 |
+---------+--------------------------------------+
| 5-244 | Unassigned |
+---------+--------------------------------------+
| 245-255 | Experimental Use |
+---------+--------------------------------------+
Table 4: Generalized Endpoint Types
The Endpoint Type field is used to cover both point-to-point and
different point-to-multipoint endpoints. A PCE may only accept
endpoint type 0; endpoint types 1-4 apply if the PCE implementation
supports P2MP path calculation. The leaf types for P2MP are as per
[RFC 8306]. A PCE not supporting a given endpoint type SHOULD respond
with a PCErr with Error-Type=4 (Not supported object) and Error-
value=7 (Unsupported endpoint type in END-POINTS Generalized Endpoint
object type). As per [RFC 5440], a PCE unable to process Generalized
Endpoints may respond with Error-Type=3 (Unknown Object) and Error-
value=2 (Unrecognized object type) or with Error-Type=4 (Not
supported object) and Error-value=2 (Not supported object Type). The
TLVs present in the request object body MUST follow the grammar per
[RFC 5511]:
<generalized-endpoint-tlvs>::=
<p2p-endpoints> | <p2mp-endpoints>
<p2p-endpoints> ::=
<endpoint> [<endpoint-restriction-list>]
<endpoint> [<endpoint-restriction-list>]
<p2mp-endpoints> ::=
<endpoint> [<endpoint-restriction-list>]
<endpoint> [<endpoint-restriction-list>]
[<endpoint> [<endpoint-restriction-list>]]...
For endpoint type Point-to-Point, two endpoint TLVs MUST be present
in the message. The first endpoint is the source, and the second is
the destination.
For endpoint type Point-to-Multipoint, several END-POINTS objects MAY
be present in the message, and the exact meaning depends on the
endpoint type defined for the object. The first endpoint TLV is the
root, and other endpoint TLVs are the leaves. The root endpoint MUST
be the same for all END-POINTS objects for that P2MP tree request.
If the root endpoint is not the same for all END-POINTS, a PCErr with
Error-Type=17 (P2MP END-POINTS Error) and Error-value=4 (The PCE
cannot satisfy the request due to inconsistent END-POINTS) MUST be
returned. The procedure defined in [RFC 8306], Section 3.10 also
applies to the Generalized Endpoint with Point-to-Multipoint endpoint
types.
An endpoint is defined as follows:
<endpoint>::=<IPV4-ADDRESS>|<IPV6-ADDRESS>|<UNNUMBERED-ENDPOINT>
<endpoint-restriction-list> ::= <endpoint-restriction>
[<endpoint-restriction-list>]
<endpoint-restriction> ::=
[<LABEL-REQUEST>][<label-restriction-list>]
<label-restriction-list> ::= <label-restriction>
[<label-restriction-list>]
<label-restriction> ::= <LABEL-SET>
The different TLVs are described in the following sections. A PCE
MAY support any or all of the IPV4-ADDRESS, IPV6-ADDRESS, and
UNNUMBERED-ENDPOINT TLVs. When receiving a PCReq, a PCE unable to
resolve the identifier in one of those TLVs MUST respond by using a
PCRep with NO-PATH and setting the bit "Unknown destination" or
"Unknown source" in the NO-PATH-VECTOR TLV. The response SHOULD
include the END-POINTS object with only the unsupported TLV(s).
A PCE MAY support either or both of the LABEL-REQUEST and LABEL-SET
TLVs. If a PCE finds a non-supported TLV in the END-POINTS, the PCE
MUST respond with a PCErr message with Error-Type=4 (Not supported
object) and Error-value=8 (Unsupported TLV present in END-POINTS
Generalized Endpoint object type), and the message SHOULD include the
END-POINTS object in the response with only the endpoint and endpoint
restriction TLV it did not understand. A PCE supporting those TLVs
but not being able to fulfill the label restriction MUST send a
response with a NO-PATH object that has the bit "No endpoint label
resource" or "No endpoint label resource in range" set in the NO-
PATH-VECTOR TLV. The response SHOULD include an END-POINTS object
containing only the TLV(s) related to the constraints the PCE could
not meet.
2.5.2. END-POINTS TLV Extensions
All endpoint TLVs have the standard PCEP TLV header as defined in
[RFC 5440], Section 7.1. For the Generalized Endpoint object type,
the TLVs MUST follow the ordering defined in Section 2.5.1.
2.5.2.1. IPV4-ADDRESS TLV
The IPV4-ADDRESS TLV (Type 39) represents a numbered endpoint using
IPv4 numbering. The format of the TLV value 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This TLV MAY be ignored, in which case a PCRep with NO-PATH SHOULD be
returned, as described in Section 2.5.1.
2.5.2.2. IPV6-ADDRESS TLV
The IPv6-ADDRESS TLV (Type 40) represents a numbered endpoint using
IPV6 numbering. The format of the TLV value 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 address (16 bytes) |
| |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This TLV MAY be ignored, in which case a PCRep with NO-PATH SHOULD be
returned, as described in Section 2.5.1.
2.5.2.3. UNNUMBERED-ENDPOINT TLV
The UNNUMBERED-ENDPOINT TLV (Type 41) represents an unnumbered
interface. This TLV has the same semantic as in [RFC 3477]. The TLV
value is encoded 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSR's Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface ID (32 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This TLV MAY be ignored, in which case a PCRep with NO-PATH SHOULD be
returned, as described in Section 2.5.1.
2.5.2.4. LABEL-REQUEST TLV
The LABEL-REQUEST TLV (Type 42) indicates the switching capability
and encoding type of the following label restriction list for the
endpoint. The value format and encoding is the same as described in
Section 3.1 of [RFC 3471] for the Generalized Label Request. The LSP
Encoding Type field indicates the encoding type, e.g., SONET, SDH,
GigE, etc., of the LSP with which the data is associated. The
Switching Type field indicates the type of switching that is being
requested on the endpoint. The Generalized Protocol Identifier
(G-PID) field identifies the payload. This TLV and the following one
are defined to satisfy requirement 13 in Section 3.1 of [RFC 7025] for
the endpoint. It is not directly related to the TE-LSP label
request, which is expressed by the SWITCH-LAYER object.
On the path calculation request, only the GENERALIZED-BANDWIDTH and
SWITCH-LAYER need to be coherent; the endpoint labels could be
different (supporting a different LABEL-REQUEST). Hence, the label
restrictions include a Generalized Label Request in order to
interpret the labels. This TLV MAY be ignored, in which case a PCRep
with NO-PATH SHOULD be returned, as described in Section 2.5.1.
2.5.2.5. LABEL-SET TLV
Label or label range restrictions can be specified for the TE-LSP
endpoints. Those are encoded using the LABEL-SET TLV. The label
value needs to be interpreted with a description on the encoding and
switching type. The REQ-ADAP-CAP object [RFC 8282] can be used in
case of a mono-layer request; however, in case of a multi-layer
request, it is possible to have more than one object, so it is better
to have a dedicated TLV for the label and label request. These TLVs
MAY be ignored, in which case a response with NO-PATH SHOULD be
returned, as described in Section 2.5.1. Per [RFC 5440], the LABEL-
SET TLV is encoded as follows. The type of the LABEL-SET TLV is 43.
The TLV Length is variable, and the value encoding follows
Section 3.5 of [RFC 3471], with the addition of a U bit, O bit, and L
bit. The L bit is used to represent a suggested set of labels,
following the semantic of Suggested Label as defined by [RFC 3471].
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Action | Reserved |L|O|U| Label Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Subchannel 1 |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: : :
: : :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Subchannel N |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
A LABEL-SET TLV represents a set of possible labels that can be used
on an interface. If the L bit is cleared, the label allocated on the
first endpoint MUST be within the label set range. The Action
parameter in the LABEL-SET indicates the type of list provided.
These parameters are described by [RFC 3471], Section 3.5.1.
The U, O, and L bits are defined as follows:
U: Upstream direction. Set for the upstream (reverse) direction
in case of bidirectional LSP.
O: Old label. Set when the TLV represents the old (previously
allocated) label in case of reoptimization. The R bit of the
RP object MUST be set to 1. If the L bit is set, this bit
SHOULD be set to 0 and ignored on receipt. When this bit is
set, the Action field MUST be set to 0 (Inclusive List), and
the LABEL-SET MUST contain one subchannel.
L: Loose label. Set when the TLV indicates to the PCE that a
set of preferred (ordered) labels are to be used. The PCE
MAY use those labels for label allocation.
Several LABEL_SET TLVs MAY be present with the O bit cleared;
LABEL_SET TLVs with the L bit set can be combined with a LABEL_SET
TLV with the L bit cleared. There MUST NOT be more than two
LABEL_SET TLVs present with the O bit set. If there are two
LABEL_SET TLVs present, there MUST NOT be more than one with the U
bit set, and there MUST NOT be more than one with the U bit cleared.
For a given U bit value, if more than one LABEL_SET TLV with the O
bit set is present, the first TLV MUST be processed, and the
following TLVs that have the same U and O bits MUST be ignored.
A LABEL-SET TLV with the O and L bits set MUST trigger a PCErr
message with Error-Type=10 (Reception of an invalid object) and
Error-value=29 (Wrong LABEL-SET TLV present with O and L bits set).
A LABEL-SET TLV that has the O bit set and an Action field not set to
0 (Inclusive List) or that contains more than one subchannel MUST
trigger a PCErr message with Error-Type=10 (Reception of an invalid
object) and Error-value=30 (Wrong LABEL-SET TLV present with O bit
set and wrong format).
If a LABEL-SET TLV is present with the O bit set, the R bit of the RP
object MUST be set; otherwise, a PCErr message MUST be sent with
Error-Type=10 (Reception of an invalid object) and Error-value=28
(LABEL-SET TLV present with O bit set but without R bit set in RP).
2.6. IRO Extension
The IRO as defined in [RFC 5440] is used to include specific objects
in the path. RSVP-TE allows the inclusion of a label definition. In
order to fulfill requirement 13 in Section 3.1 of [RFC 7025], the IRO
needs to support the new subobject type as defined in [RFC 3473]:
+======+===========+
| Type | Subobject |
+======+===========+
| 10 | Label |
+------+-----------+
Table 5
The Label subobject MUST follow a subobject identifying a link,
currently an IP address subobject (Type 1 or 2) or an interface ID
(Type 4) subobject. If an IP address subobject is used, then the
given IP address MUST be associated with a link. More than one Label
subobject MAY follow each subobject identifying a link. The
procedure associated with this subobject is as follows.
If the PCE is able to allocate labels (e.g., via explicit label
control), the PCE MUST allocate one label from within the set of
label values for the given link. If the PCE does not assign labels,
then it sends a response with a NO-PATH object, containing a NO-PATH-
VECTOR TLV with the bit "No label resource in range" set.
2.7. XRO Extension
The XRO as defined in [RFC 5521] is used to exclude specific objects
in the path. RSVP-TE allows the exclusion of certain labels
[RFC 6001]. In order to fulfill requirement 13 in Section 3.1 of
[RFC 7025], the PCEP's XRO needs to support a new subobject to enable
label exclusion.
The encoding of the XRO Label subobject follows the encoding of the
ERO Label subobject defined in [RFC 3473] and the XRO subobject
defined in [RFC 5521]. The XRO Label subobject (Type 10) represents
one label and is defined 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|X| Type=10 | Length |U| Reserved | C-Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
X (1 bit): See [RFC 5521]. The X bit indicates whether the exclusion
is mandatory or desired. 0 indicates that the resource specified
MUST be excluded from the path computed by the PCE. 1 indicates
that the resource specified SHOULD be excluded from the path
computed by the PCE, but it MAY be included subject to the PCE
policy and the absence of a viable path that meets the other
constraints and excludes the resource.
Type (7 bits): The type of the XRO Label subobject is 10.
Length (8 bits): See [RFC 5521]. The total length of the subobject
in bytes (including the Type and Length fields). The length is
always divisible by 4.
U (1 bit): See [RFC 3471], Section 6.1.
C-Type (8 bits): The C-Type of the included Label object as defined
in [RFC 3473].
Label: See [RFC 3471].
The Label subobject MUST follow a subobject identifying a link,
currently an IP address subobject (Type 1 or 2) or an interface ID
(Type 4) subobject. If an IP address subobject is used, the given IP
address MUST be associated with a link. More than one label
subobject MAY follow a subobject identifying a link.
+======+===========+
| Type | Subobject |
+======+===========+
| 10 | Label |
+------+-----------+
Table 6
2.8. LSPA Extensions
The LSPA carries the LSP attributes. In the end-to-end recovery
context, this also includes the protection state information. A new
TLV is defined to fulfill requirement 7 in Section 3.1 of [RFC 7025]
and requirement 3 in Section 3.2 of [RFC 7025]. This TLV contains the
information of the PROTECTION object defined by [RFC 4872] and can be
used as a policy input. The LSPA object MAY carry a PROTECTION-
ATTRIBUTE TLV (Type 44), which is defined 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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|S|P|N|O| Reserved | LSP Flags | Reserved | Link Flags|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|I|R| Reserved | Seg.Flags | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The content is as defined in [RFC 4872], Section 14 and [RFC 4873],
Section 6.1.
The LSP (protection) Flags field or the Link Flags field can be used
by a PCE implementation for routing policy input. The other
attributes are only meaningful for a stateful PCE.
This TLV is OPTIONAL and MAY be ignored by the PCE. If ignored by
the PCE, it MUST NOT include the TLV in the LSPA of the response.
When the TLV is used by the PCE, an LSPA object and the PROTECTION-
ATTRIBUTE TLV MUST be included in the response. Fields that were not
considered MUST be set to 0.
2.9. NO-PATH Object Extension
The NO-PATH object is used in PCRep messages in response to an
unsuccessful Path Computation Request (the PCE could not find a path
satisfying the set of constraints). In this scenario, the PCE MUST
include a NO-PATH object in the PCRep message. The NO-PATH object
MAY carry the NO-PATH-VECTOR TLV that specifies more information on
the reasons that led to a negative reply. In case of GMPLS networks,
there could be some additional constraints that led to the failure
such as protection mismatch, lack of resources, and so on. Several
new flags have been defined in the 32-bit Flag field of the NO-PATH-
VECTOR TLV, but no modifications have been made in the NO-PATH
object.
2.9.1. Extensions to NO-PATH-VECTOR TLV
The modified NO-PATH-VECTOR TLV carrying the additional information
is as follows:
Bit number 18: Protection Mismatch (1 bit). Specifies the
mismatch of the protection type in the PROTECTION-ATTRIBUTE TLV
in the request.
Bit number 17: No Resource (1 bit). Specifies that the resources
are not currently sufficient to provide the path.
Bit number 16: Granularity not supported (1 bit). Specifies that
the PCE is not able to provide a path with the requested
granularity.
Bit number 15: No endpoint label resource (1 bit). Specifies
that the PCE is not able to provide a path because of the
endpoint label restriction.
Bit number 14: No endpoint label resource in range (1 bit).
Specifies that the PCE is not able to provide a path because of
the endpoint label set restriction.
Bit number 13: No label resource in range (1 bit). Specifies
that the PCE is not able to provide a path because of the label
set restriction.
Bit number 12: LOAD-BALANCING could not be performed with the
bandwidth constraints (1 bit). Specifies that the PCE is not
able to provide a path because it could not map the BANDWIDTH
into the parameters specified by the LOAD-BALANCING.
3. Additional Error-Types and Error-Values Defined
A PCEP-ERROR object is used to report a PCEP error and is
characterized by an Error-Type that specifies the type of error and
an Error-value that provides additional information about the error.
An additional Error-Type and several Error-values are defined to
represent some of the errors related to the newly identified objects,
which are related to GMPLS networks. For each PCEP error, an Error-
Type and an Error-value are defined. Error-Types 1 to 10 are already
defined in [RFC 5440]. Additional Error-values are defined for Error-
Types 4 and 10. A new Error-Type 29 (Path computation failure) is
defined in this document.
Error-Type 29 (Path computation failure) is used to reflect
constraints not understood by the PCE, for instance, when the PCE is
not able to understand the Generalized bandwidth. If the constraints
are understood, but the PCE is unable to find those constraints, NO-
PATH is to be used.
+============+===============+==============================+
| Error-Type | Meaning | Error-value |
+============+===============+==============================+
| 4 | Not supported | |
| | object | |
+------------+---------------+------------------------------+
| | | 6: BANDWIDTH object type 3 |
| | | or 4 not supported |
+------------+---------------+------------------------------+
| | | 7: Unsupported endpoint type |
| | | in END-POINTS Generalized |
| | | Endpoint object type |
+------------+---------------+------------------------------+
| | | 8: Unsupported TLV present |
| | | in END-POINTS Generalized |
| | | Endpoint object type |
+------------+---------------+------------------------------+
| | | 9: Unsupported granularity |
| | | in the RP object flags |
+------------+---------------+------------------------------+
| 10 | Reception of | |
| | an invalid | |
| | object | |
+------------+---------------+------------------------------+
| | | 24: Bad BANDWIDTH object |
| | | type 3 or 4 |
+------------+---------------+------------------------------+
| | | 25: Unsupported LSP |
| | | Protection Flags in |
| | | PROTECTION-ATTRIBUTE TLV |
+------------+---------------+------------------------------+
| | | 26: Unsupported Secondary |
| | | LSP Protection Flags in |
| | | PROTECTION-ATTRIBUTE TLV |
+------------+---------------+------------------------------+
| | | 27: Unsupported Link |
| | | Protection Type in |
| | | PROTECTION-ATTRIBUTE TLV |
+------------+---------------+------------------------------+
| | | 28: LABEL-SET TLV present |
| | | with O bit set but without R |
| | | bit set in RP |
+------------+---------------+------------------------------+
| | | 29: Wrong LABEL-SET TLV |
| | | present with O and L bits |
| | | set |
+------------+---------------+------------------------------+
| | | 30: Wrong LABEL-SET TLV |
| | | present with O bit set and |
| | | wrong format |
+------------+---------------+------------------------------+
| | | 31: Missing GMPLS-CAPABILITY |
| | | TLV |
+------------+---------------+------------------------------+
| 29 | Path | |
| | computation | |
| | failure | |
+------------+---------------+------------------------------+
| | | 0: Unassigned |
+------------+---------------+------------------------------+
| | | 1: Unacceptable request |
| | | message |
+------------+---------------+------------------------------+
| | | 2: Generalized bandwidth |
| | | value not supported |
+------------+---------------+------------------------------+
| | | 3: Label set constraint |
| | | could not be met |
+------------+---------------+------------------------------+
| | | 4: Label constraint could |
| | | not be met |
+------------+---------------+------------------------------+
Table 7
4. Manageability Considerations
This section follows the guidance of [RFC 6123].
4.1. Control of Function through Configuration and Policy
This document makes no change to the basic operation of PCEP, so the
requirements described in [RFC 5440], Section 8.1 also apply to this
document. In addition to those requirements, a PCEP implementation
may allow the configuration of the following parameters:
* Accepted RG in the RP object.
* Default RG to use (overriding the one present in the PCReq).
* Accepted BANDWIDTH object type 3 and 4 parameters in the request
and default mapping to use when not specified in the request.
* Accepted LOAD-BALANCING object type 2 parameters in request.
* Accepted endpoint type and allowed TLVs in object END-POINTS with
the object type Generalized Endpoint.
* Accepted range for label restrictions in END-POINTS or IRO/XRO
objects.
* Acceptance and suppression of the PROTECTION-ATTRIBUTE TLV.
The configuration of the above parameters is applicable to the
different sessions as described in [RFC 5440], Section 8.1 (by
default, per PCEP peer, etc.).
4.2. Information and Data Models
This document makes no change to the basic operation of PCEP, so the
requirements described in [RFC 5440], Section 8.2 also apply to this
document. This document does not introduce any new ERO subobjects;
the ERO information model is already covered in [RFC 4802].
4.3. Liveness Detection and Monitoring
This document makes no change to the basic operation of PCEP, so
there are no changes to the requirements for liveness detection and
monitoring in [RFC 4657] and [RFC 5440], Section 8.3.
4.4. Verifying Correct Operation
This document makes no change to the basic operations of PCEP and the
considerations described in [RFC 5440], Section 8.4. New errors
defined by this document should satisfy the requirement to log error
events.
4.5. Requirements on Other Protocols and Functional Components
No new requirements on other protocols and functional components are
made by this document. This document does not require ERO object
extensions. Any new ERO subobject defined in the TEAS or CCAMP
Working Groups can be adopted without modifying the operations
defined in this document.
4.6. Impact on Network Operation
This document makes no change to the basic operations of PCEP and the
considerations described in [RFC 5440], Section 8.6. In addition to
the limit on the rate of messages sent by a PCEP speaker, a limit MAY
be placed on the size of the PCEP messages.
5. IANA Considerations
IANA assigns values to PCEP objects and TLVs. IANA has made
allocations for the newly defined objects and TLVs defined in this
document. In addition, IANA manages the space of flags that have
been newly added in the TLVs.
5.1. PCEP Objects
New object types are defined in Sections 2.3, 2.4, and 2.5.1. IANA
has made the following Object-Type allocations in the "PCEP Objects"
subregistry.
+==============+================+=================+===========+
| Object-Class | Name | Object-Type | Reference |
| Value | | | |
+==============+================+=================+===========+
| 5 | BANDWIDTH | 3: Generalized | RFC 8779, |
| | | bandwidth | Section |
| | | | 2.3 |
+--------------+----------------+-----------------+-----------+
| | | 4: Generalized | RFC 8779, |
| | | bandwidth of an | Section |
| | | existing TE-LSP | 2.3 |
| | | for which a | |
| | | reoptimization | |
| | | is requested | |
+--------------+----------------+-----------------+-----------+
| 14 | LOAD-BALANCING | 2: Generalized | RFC 8779, |
| | | Load Balancing | Section |
| | | | 2.4 |
+--------------+----------------+-----------------+-----------+
| 4 | END-POINTS | 5: Generalized | RFC 8779, |
| | | Endpoint | Section |
| | | | 2.5 |
+--------------+----------------+-----------------+-----------+
Table 8
5.2. Endpoint Type Field in the Generalized END-POINTS Object
IANA has created a new "Generalized Endpoint Types" registry to
manage the Endpoint Type field of the END-POINTS object, the object
type Generalized Endpoint, and the code space.
New endpoint types in the Unassigned range are assigned by Standards
Action [RFC 8126]. Each endpoint type should be tracked with the
following attributes:
* Value
* Type
* Defining RFC
New endpoint types in the Experimental Use range will not be
registered with IANA and MUST NOT be mentioned by any RFCs.
The following values are defined by this document (see Table 4 in
Section 2.5.1):
+=========+======================================+
| Value | Type |
+=========+======================================+
| 0 | Point-to-Point |
+---------+--------------------------------------+
| 1 | Point-to-Multipoint with leaf type 1 |
+---------+--------------------------------------+
| 2 | Point-to-Multipoint with leaf type 2 |
+---------+--------------------------------------+
| 3 | Point-to-Multipoint with leaf type 3 |
+---------+--------------------------------------+
| 4 | Point-to-Multipoint with leaf type 4 |
+---------+--------------------------------------+
| 5-244 | Unassigned |
+---------+--------------------------------------+
| 245-255 | Experimental Use |
+---------+--------------------------------------+
Table 9
5.3. New PCEP TLVs
IANA manages a registry for PCEP TLV code points (see [RFC 5440]),
which is maintained as the "PCEP TLV Type Indicators" subregistry of
the "Path Computation Element Protocol (PCEP) Numbers" registry.
IANA has allocated the following per this document:
+=======+======================+===========================+
| Value | Meaning | Reference |
+=======+======================+===========================+
| 39 | IPV4-ADDRESS | RFC 8779, Section 2.5.2.1 |
+-------+----------------------+---------------------------+
| 40 | IPV6-ADDRESS | RFC 8779, Section 2.5.2.2 |
+-------+----------------------+---------------------------+
| 41 | UNNUMBERED-ENDPOINT | RFC 8779, Section 2.5.2.3 |
+-------+----------------------+---------------------------+
| 42 | LABEL-REQUEST | RFC 8779, Section 2.5.2.4 |
+-------+----------------------+---------------------------+
| 43 | LABEL-SET | RFC 8779, Section 2.5.2.5 |
+-------+----------------------+---------------------------+
| 44 | PROTECTION-ATTRIBUTE | RFC 8779, Section 2.8 |
+-------+----------------------+---------------------------+
| 45 | GMPLS-CAPABILITY | RFC 8779, Section 2.1.2 |
+-------+----------------------+---------------------------+
Table 10
5.4. RP Object Flag Field
A new flag is defined in Section 2.2 for the Flags field of the RP
object. IANA has made the following allocation in the "RP Object
Flag Field" subregistry:
+=======+==========================+=======================+
| Bit | Description | Reference |
+=======+==========================+=======================+
| 15-16 | Routing Granularity (RG) | RFC 8779, Section 2.2 |
+-------+--------------------------+-----------------------+
Table 11
5.5. New PCEP Error Codes
New PCEP Error-Types and Error-values are defined in Section 3. IANA
has made the following allocations in the "PCEP-ERROR Object Error
Types and Values" registry:
+============+=============+==========================+===========+
| Error-Type | Meaning | Error-value | Reference |
+============+=============+==========================+===========+
| 4 | Not | | [RFC 5440] |
| | supported | | |
| | object | | |
+------------+-------------+--------------------------+-----------+
| | | 6: BANDWIDTH object type | RFC 8779 |
| | | 3 or 4 not supported | |
+------------+-------------+--------------------------+-----------+
| | | 7: Unsupported endpoint | RFC 8779 |
| | | type in END-POINTS | |
| | | Generalized Endpoint | |
| | | object type | |
+------------+-------------+--------------------------+-----------+
| | | 8: Unsupported TLV | RFC 8779 |
| | | present in END-POINTS | |
| | | Generalized Endpoint | |
| | | object type | |
+------------+-------------+--------------------------+-----------+
| | | 9: Unsupported | RFC 8779 |
| | | granularity in the RP | |
| | | object flags | |
+------------+-------------+--------------------------+-----------+
| 10 | Reception | | [RFC 5440] |
| | of an | | |
| | invalid | | |
| | object | | |
+------------+-------------+--------------------------+-----------+
| | | 24: Bad BANDWIDTH object | RFC 8779 |
| | | type 3 or 4 | |
+------------+-------------+--------------------------+-----------+
| | | 25: Unsupported LSP | RFC 8779 |
| | | Protection Flags in | |
| | | PROTECTION-ATTRIBUTE TLV | |
+------------+-------------+--------------------------+-----------+
| | | 26: Unsupported | RFC 8779 |
| | | Secondary LSP Protection | |
| | | Flags in PROTECTION- | |
| | | ATTRIBUTE TLV | |
+------------+-------------+--------------------------+-----------+
| | | 27: Unsupported Link | RFC 8779 |
| | | Protection Type in | |
| | | PROTECTION-ATTRIBUTE TLV | |
+------------+-------------+--------------------------+-----------+
| | | 28: LABEL-SET TLV | RFC 8779 |
| | | present with O bit set | |
| | | but without R bit set in | |
| | | RP | |
+------------+-------------+--------------------------+-----------+
| | | 29: Wrong LABEL-SET TLV | RFC 8779 |
| | | present with O and L | |
| | | bits set | |
+------------+-------------+--------------------------+-----------+
| | | 30: Wrong LABEL-SET TLV | RFC 8779 |
| | | present with O bit set | |
| | | and wrong format | |
+------------+-------------+--------------------------+-----------+
| | | 31: Missing GMPLS- | RFC 8779 |
| | | CAPABILITY TLV | |
+------------+-------------+--------------------------+-----------+
| 29 | Path | | RFC 8779 |
| | computation | | |
| | failure | | |
+------------+-------------+--------------------------+-----------+
| | | 0: Unassigned | RFC 8779 |
+------------+-------------+--------------------------+-----------+
| | | 1: Unacceptable request | RFC 8779 |
| | | message | |
+------------+-------------+--------------------------+-----------+
| | | 2: Generalized bandwidth | RFC 8779 |
| | | value not supported | |
+------------+-------------+--------------------------+-----------+
| | | 3: Label set constraint | RFC 8779 |
| | | could not be met | |
+------------+-------------+--------------------------+-----------+
| | | 4: Label constraint | RFC 8779 |
| | | could not be met | |
+------------+-------------+--------------------------+-----------+
Table 12
5.6. New Bits in NO-PATH-VECTOR TLV
New NO-PATH-VECTOR TLV bits are defined in Section 2.9.1. IANA has
made the following allocations in the "NO-PATH-VECTOR TLV Flag Field"
subregistry:
+=====+=======================================+===========+
| Bit | Description | Reference |
+=====+=======================================+===========+
| 18 | Protection Mismatch | RFC 8779 |
+-----+---------------------------------------+-----------+
| 17 | No Resource | RFC 8779 |
+-----+---------------------------------------+-----------+
| 16 | Granularity not supported | RFC 8779 |
+-----+---------------------------------------+-----------+
| 15 | No endpoint label resource | RFC 8779 |
+-----+---------------------------------------+-----------+
| 14 | No endpoint label resource in range | RFC 8779 |
+-----+---------------------------------------+-----------+
| 13 | No label resource in range | RFC 8779 |
+-----+---------------------------------------+-----------+
| 12 | LOAD-BALANCING could not be performed | RFC 8779 |
| | with the bandwidth constraints | |
+-----+---------------------------------------+-----------+
Table 13
5.7. New Subobject for the Include Route Object
IANA has added a new subobject in the "IRO Subobjects" subregistry of
the "Path Computation Element Protocol (PCEP) Numbers" registry.
IANA has added a new subobject that can be carried in the IRO as
follows:
+=======+=============+===========+
| Value | Description | Reference |
+=======+=============+===========+
| 10 | Label | RFC 8779 |
+-------+-------------+-----------+
Table 14
5.8. New Subobject for the Exclude Route Object
IANA has added a new subobject in the "XRO Subobjects" subregistry of
the "Path Computation Element Protocol (PCEP) Numbers" registry.
IANA has added a new subobject that can be carried in the XRO as
follows:
+=======+=============+===========+
| Value | Description | Reference |
+=======+=============+===========+
| 10 | Label | RFC 8779 |
+-------+-------------+-----------+
Table 15
5.9. New GMPLS-CAPABILITY TLV Flag Field
IANA has created a new "GMPLS-CAPABILITY TLV Flag Field" subregistry
within the "Path Computation Element Protocol (PCEP) Numbers"
registry to manage the Flag field of the GMPLS-CAPABILITY TLV.
New bit numbers are to be assigned by Standards Action [RFC 8126].
Each bit should be tracked with the following qualities:
* Bit number (counting from bit 0 as the most significant bit)
* Capability description
* Defining RFC
The initial contents of the subregistry are empty, with bits 0-31
marked as Unassigned.
6. Security Considerations
GMPLS controls multiple technologies and types of network elements.
The LSPs that are established using GMPLS, whose paths can be
computed using the PCEP extensions to support GMPLS described in this
document, can carry a high volume of traffic and can be a critical
part of a network infrastructure. The PCE can then play a key role
in the use of the resources and in determining the physical paths of
the LSPs; thus, it is important to ensure the identity of the PCE and
PCC, as well as the communication channel. In many deployments,
there will be a completely isolated network where an external attack
is of very low probability. However, there are other deployment
cases in which the PCC-PCE communication can be more exposed, and
there could be more security considerations. There are three main
situations in case an attack in the GMPLS PCE context happens:
PCE Identity theft: A legitimate PCC could request a path for a
GMPLS LSP to a malicious PCE, which poses as a legitimate PCE.
The response may be that the LSP traverses some geographical
place known to the attacker where confidentiality (sniffing),
integrity (traffic modification), or availability (traffic
drop) attacks could be performed by use of an attacker-
controlled middlebox device. Also, the resulting LSP can omit
constraints given in the requests (e.g., excluding certain
fibers and avoiding some SRLGs), which could make the LSP that
will be set up later look perfectly fine, but it will be in a
risky situation. Also, the result can lead to the creation of
an LSP that does not provide the desired quality and gives less
resources than necessary.
PCC Identity theft: A malicious PCC, acting as a legitimate PCC,
requesting LSP paths to a legitimate PCE can obtain a good
knowledge of the physical topology of a critical
infrastructure. It could learn enough details to plan a later
physical attack.
Message inspection: As in the previous case, knowledge of an
infrastructure can be obtained by sniffing PCEP messages.
The security mechanisms can provide authentication and
confidentiality for those scenarios where PCC-PCE communication
cannot be completely trusted. [RFC 8253] provides origin
verification, message integrity, and replay protection, and it
ensures that a third party cannot decipher the contents of a message.
In order to protect against the malicious PCE case, the PCC SHOULD
have policies in place to accept or not accept the path provided by
the PCE. Those policies can verify if the path follows the provided
constraints. In addition, a technology-specific data-plane mechanism
can be used (following [RFC 5920], Section 5.8) to verify the data-
plane connectivity and deviation from constraints.
The usage of Transport Layer Security (TLS) to enhance PCEP security
is described in [RFC 8253]. The document describes the initiation of
TLS procedures, the TLS handshake mechanisms, the TLS methods for
peer authentication, the applicable TLS ciphersuites for data
exchange, and the handling of errors in the security checks. PCE and
PCC SHOULD use the mechanism in [RFC 8253] to protect against
malicious PCC and PCE.
Finally, as mentioned by [RFC 7025], the PCEP extensions that support
GMPLS should be considered under the same security as current PCE
work, and this extension will not change the underlying security
issues. However, given the critical nature of the network
infrastructures under control by GMPLS, the security issues described
above should be seriously considered when deploying a GMPLS-PCE-based
control plane for such networks. For an overview of the security
considerations, not only related to PCE/PCEP, and vulnerabilities of
a GMPLS control plane, see [RFC 5920].
7. References
7.1. Normative References
[G.709-v3] ITU-T, "Interfaces for the optical transport network",
Recommendation G.709/Y.1331, June 2016,
<https://www.itu.int/rec/T-REC-G.709-201606-I/en>.
[RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC 2119, March 1997,
<https://www.rfc-editor.org/info/RFC 2119>.
[RFC 2210] Wroclawski, J., "The Use of RSVP with IETF Integrated
Services", RFC 2210, DOI 10.17487/RFC 2210, September 1997,
<https://www.rfc-editor.org/info/RFC 2210>.
[RFC 3209] 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/RFC 3209, December 2001,
<https://www.rfc-editor.org/info/RFC 3209>.
[RFC 3471] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Functional Description",
RFC 3471, DOI 10.17487/RFC 3471, January 2003,
<https://www.rfc-editor.org/info/RFC 3471>.
[RFC 3473] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
DOI 10.17487/RFC 3473, January 2003,
<https://www.rfc-editor.org/info/RFC 3473>.
[RFC 3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links
in Resource ReSerVation Protocol - Traffic Engineering
(RSVP-TE)", RFC 3477, DOI 10.17487/RFC 3477, January 2003,
<https://www.rfc-editor.org/info/RFC 3477>.
[RFC 3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630,
DOI 10.17487/RFC 3630, September 2003,
<https://www.rfc-editor.org/info/RFC 3630>.
[RFC 4003] Berger, L., "GMPLS Signaling Procedure for Egress
Control", RFC 4003, DOI 10.17487/RFC 4003, February 2005,
<https://www.rfc-editor.org/info/RFC 4003>.
[RFC 4328] Papadimitriou, D., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Extensions for G.709 Optical
Transport Networks Control", RFC 4328,
DOI 10.17487/RFC 4328, January 2006,
<https://www.rfc-editor.org/info/RFC 4328>.
[RFC 4606] Mannie, E. and D. Papadimitriou, "Generalized Multi-
Protocol Label Switching (GMPLS) Extensions for
Synchronous Optical Network (SONET) and Synchronous
Digital Hierarchy (SDH) Control", RFC 4606,
DOI 10.17487/RFC 4606, August 2006,
<https://www.rfc-editor.org/info/RFC 4606>.
[RFC 4802] Nadeau, T., Ed. and A. Farrel, Ed., "Generalized
Multiprotocol Label Switching (GMPLS) Traffic Engineering
Management Information Base", RFC 4802,
DOI 10.17487/RFC 4802, February 2007,
<https://www.rfc-editor.org/info/RFC 4802>.
[RFC 4872] Lang, J.P., 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/RFC 4872, May 2007,
<https://www.rfc-editor.org/info/RFC 4872>.
[RFC 4873] Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel,
"GMPLS Segment Recovery", RFC 4873, DOI 10.17487/RFC 4873,
May 2007, <https://www.rfc-editor.org/info/RFC 4873>.
[RFC 5088] Le Roux, JL., Ed., Vasseur, JP., Ed., Ikejiri, Y., and R.
Zhang, "OSPF Protocol Extensions for Path Computation
Element (PCE) Discovery", RFC 5088, DOI 10.17487/RFC 5088,
January 2008, <https://www.rfc-editor.org/info/RFC 5088>.
[RFC 5089] Le Roux, JL., Ed., Vasseur, JP., Ed., Ikejiri, Y., and R.
Zhang, "IS-IS Protocol Extensions for Path Computation
Element (PCE) Discovery", RFC 5089, DOI 10.17487/RFC 5089,
January 2008, <https://www.rfc-editor.org/info/RFC 5089>.
[RFC 5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC 5440, March 2009,
<https://www.rfc-editor.org/info/RFC 5440>.
[RFC 5511] Farrel, A., "Routing Backus-Naur Form (RBNF): A Syntax
Used to Form Encoding Rules in Various Routing Protocol
Specifications", RFC 5511, DOI 10.17487/RFC 5511, April
2009, <https://www.rfc-editor.org/info/RFC 5511>.
[RFC 5520] Bradford, R., Ed., Vasseur, JP., and A. Farrel,
"Preserving Topology Confidentiality in Inter-Domain Path
Computation Using a Path-Key-Based Mechanism", RFC 5520,
DOI 10.17487/RFC 5520, April 2009,
<https://www.rfc-editor.org/info/RFC 5520>.
[RFC 5521] Oki, E., Takeda, T., and A. Farrel, "Extensions to the
Path Computation Element Communication Protocol (PCEP) for
Route Exclusions", RFC 5521, DOI 10.17487/RFC 5521, April
2009, <https://www.rfc-editor.org/info/RFC 5521>.
[RFC 5541] Le Roux, JL., Vasseur, JP., and Y. Lee, "Encoding of
Objective Functions in the Path Computation Element
Communication Protocol (PCEP)", RFC 5541,
DOI 10.17487/RFC 5541, June 2009,
<https://www.rfc-editor.org/info/RFC 5541>.
[RFC 6001] Papadimitriou, D., Vigoureux, M., Shiomoto, K., Brungard,
D., and JL. Le Roux, "Generalized MPLS (GMPLS) Protocol
Extensions for Multi-Layer and Multi-Region Networks (MLN/
MRN)", RFC 6001, DOI 10.17487/RFC 6001, October 2010,
<https://www.rfc-editor.org/info/RFC 6001>.
[RFC 6003] Papadimitriou, D., "Ethernet Traffic Parameters",
RFC 6003, DOI 10.17487/RFC 6003, October 2010,
<https://www.rfc-editor.org/info/RFC 6003>.
[RFC 6205] Otani, T., Ed. and D. Li, Ed., "Generalized Labels for
Lambda-Switch-Capable (LSC) Label Switching Routers",
RFC 6205, DOI 10.17487/RFC 6205, March 2011,
<https://www.rfc-editor.org/info/RFC 6205>.
[RFC 6387] Takacs, A., Berger, L., Caviglia, D., Fedyk, D., and J.
Meuric, "GMPLS Asymmetric Bandwidth Bidirectional Label
Switched Paths (LSPs)", RFC 6387, DOI 10.17487/RFC 6387,
September 2011, <https://www.rfc-editor.org/info/RFC 6387>.
[RFC 7139] Zhang, F., Ed., Zhang, G., Belotti, S., Ceccarelli, D.,
and K. Pithewan, "GMPLS Signaling Extensions for Control
of Evolving G.709 Optical Transport Networks", RFC 7139,
DOI 10.17487/RFC 7139, March 2014,
<https://www.rfc-editor.org/info/RFC 7139>.
[RFC 7570] Margaria, C., Ed., Martinelli, G., Balls, S., and B.
Wright, "Label Switched Path (LSP) Attribute in the
Explicit Route Object (ERO)", RFC 7570,
DOI 10.17487/RFC 7570, July 2015,
<https://www.rfc-editor.org/info/RFC 7570>.
[RFC 7792] Zhang, F., Zhang, X., Farrel, A., Gonzalez de Dios, O.,
and D. Ceccarelli, "RSVP-TE Signaling Extensions in
Support of Flexi-Grid Dense Wavelength Division
Multiplexing (DWDM) Networks", RFC 7792,
DOI 10.17487/RFC 7792, March 2016,
<https://www.rfc-editor.org/info/RFC 7792>.
[RFC 8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC 8126, June 2017,
<https://www.rfc-editor.org/info/RFC 8126>.
[RFC 8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC 8174,
May 2017, <https://www.rfc-editor.org/info/RFC 8174>.
[RFC 8253] 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/RFC 8253, October 2017,
<https://www.rfc-editor.org/info/RFC 8253>.
[RFC 8282] Oki, E., Takeda, T., Farrel, A., and F. Zhang, "Extensions
to the Path Computation Element Communication Protocol
(PCEP) for Inter-Layer MPLS and GMPLS Traffic
Engineering", RFC 8282, DOI 10.17487/RFC 8282, December
2017, <https://www.rfc-editor.org/info/RFC 8282>.
[RFC 8306] Zhao, Q., Dhody, D., Ed., Palleti, R., and D. King,
"Extensions to the Path Computation Element Communication
Protocol (PCEP) for Point-to-Multipoint Traffic
Engineering Label Switched Paths", RFC 8306,
DOI 10.17487/RFC 8306, November 2017,
<https://www.rfc-editor.org/info/RFC 8306>.
7.2. Informative References
[RFC 4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
Computation Element (PCE)-Based Architecture", RFC 4655,
DOI 10.17487/RFC 4655, August 2006,
<https://www.rfc-editor.org/info/RFC 4655>.
[RFC 4657] Ash, J., Ed. and J.L. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol Generic
Requirements", RFC 4657, DOI 10.17487/RFC 4657, September
2006, <https://www.rfc-editor.org/info/RFC 4657>.
[RFC 5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, DOI 10.17487/RFC 5920, July 2010,
<https://www.rfc-editor.org/info/RFC 5920>.
[RFC 6123] Farrel, A., "Inclusion of Manageability Sections in Path
Computation Element (PCE) Working Group Drafts", RFC 6123,
DOI 10.17487/RFC 6123, February 2011,
<https://www.rfc-editor.org/info/RFC 6123>.
[RFC 6163] Lee, Y., Ed., Bernstein, G., Ed., and W. Imajuku,
"Framework for GMPLS and Path Computation Element (PCE)
Control of Wavelength Switched Optical Networks (WSONs)",
RFC 6163, DOI 10.17487/RFC 6163, April 2011,
<https://www.rfc-editor.org/info/RFC 6163>.
[RFC 7025] Otani, T., Ogaki, K., Caviglia, D., Zhang, F., and C.
Margaria, "Requirements for GMPLS Applications of PCE",
RFC 7025, DOI 10.17487/RFC 7025, September 2013,
<https://www.rfc-editor.org/info/RFC 7025>.
[RFC 7449] Lee, Y., Ed., Bernstein, G., Ed., Martensson, J., Takeda,
T., Tsuritani, T., and O. Gonzalez de Dios, "Path
Computation Element Communication Protocol (PCEP)
Requirements for Wavelength Switched Optical Network
(WSON) Routing and Wavelength Assignment", RFC 7449,
DOI 10.17487/RFC 7449, February 2015,
<https://www.rfc-editor.org/info/RFC 7449>.
Appendix A. LOAD-BALANCING Usage for SDH Virtual Concatenation
As an example, a request for one co-signaled n x VC-4 TE-LSP will not
use LOAD-BALANCING. In case the VC-4 components can use different
paths, the BANDWIDTH with object type 3 will contain the complete n x
VC-4 traffic specification, and the LOAD-BALANCING object will
contain the minimum co-signaled VC-4. For an SDH network, a request
for a TE-LSP group with 10 VC-4 containers, with each path using at
minimum 2 x VC-4 containers, can be represented with a BANDWIDTH
object with object type 3, the Bw Spec Type set to 4, and the content
of the Generalized Bandwidth field with ST=6, RCC=0, NCC=0, NVC=10,
and MT=1. The LOAD-BALANCING with object type 2 with the Bw Spec
Type set to 4 and Max-LSP=5, Min Bandwidth Spec is ST=6, RCC=0,
NCC=0, NVC=2, MT=1. The PCE can respond with a maximum of 5 paths,
with each path having a BANDWIDTH object type 3 and a Generalized
Bandwidth field matching the Min Bandwidth Spec from the LOAD-
BALANCING object of the corresponding request.
Acknowledgments
The research of Ramon Casellas, Francisco Javier Jimenez Chico, Oscar
Gonzalez de Dios, Cyril Margaria, and Franz Rambach that led to the
results in this document received funding from the European
Community's Seventh Framework Program FP7/2007-2013 under grant
agreement no. 247674 and no. 317999.
The authors would like to thank Julien Meuric, Lyndon Ong, Giada
Lander, Jonathan Hardwick, Diego Lopez, David Sinicrope, Vincent
Roca, Dhruv Dhody, Adrian Farrel, and Tianran Zhou for their review
and useful comments.
Thanks to Alisa Cooper, Benjamin Kaduk, Elwyn Davies, Martin
Vigoureux, Roman Danyliw, and Suresh Krishnan for the IESG-related
comments.
Contributors
Elie Sfeir
Coriant
St. Martin Strasse 76
81541 Munich
Germany
Email: elie.sfeir@coriant.com
Franz Rambach
Nockherstrasse 2-4
81541 Munich
Germany
Phone: +49 178 8855738
Email: franz.rambach@cgi.com
Francisco Javier Jimenez Chico
Telefonica Investigacion y Desarrollo
C/ Emilio Vargas 6
28043 Madrid
Spain
Phone: +34 91 3379037
Email: fjjc@tid.es
Suresh Babu
Email: sureshhimnish@gmail.com
Young Lee
Samsung Electronics
Email: younglee.tx@gmail.com
Senthil Kumar S
Email: ssenthilkumar@gmail.com
Jun Sun
Huawei Technologies
Shenzhen
China
Email: johnsun@huawei.com
Ramon Casellas
CTTC - Centre Tecnologic de Telecomunicacions de Catalunya
PMT Ed B4 Av. Carl Friedrich Gauss 7
08660 Castelldefels, Barcelona
Spain
Phone: +34 93 6452916
Email: ramon.casellas@cttc.e
Authors' Addresses
Cyril Margaria (editor)
Juniper
Email: cmargaria@juniper.net
Oscar Gonzalez de Dios (editor)
Telefonica Investigacion y Desarrollo
C/ Ronda de la Comunicacion
28050 Madrid
Spain
Phone: +34 91 4833441
Email: oscar.gonzalezdedios@telefonica.com
Fatai Zhang (editor)
Huawei Technologies
F3-5-B R&D Center, Huawei Base
Bantian, Longgang District
Shenzhen
518129
China
Email: zhangfatai@huawei.com
RFC TOTAL SIZE: 103205 bytes
PUBLICATION DATE: Wednesday, July 22nd, 2020
LEGAL RIGHTS: The IETF Trust (see BCP 78)
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