draft-ietf-pce-hierarchy-extensions-03.txt   draft-ietf-pce-hierarchy-extensions-04.txt 
Network Working Group F. Zhang
PCE Working Group F. Zhang
Internet-Draft Q. Zhao Internet-Draft Q. Zhao
Intended status: Standards Track Huawei Intended status: Standards Track Huawei
Expires: January 8, 2017 O. Gonzalez de Dios Expires: September 6, 2018 O. Gonzalez de Dios
Telefonica I+D Telefonica I+D
R. Casellas R. Casellas
CTTC CTTC
D. King D. King
Old Dog Consulting Old Dog Consulting
July 7, 2016 March 5, 2018
Extensions to Path Computation Element Communication Protocol (PCEP) for Extensions to Path Computation Element Communication Protocol (PCEP) for
Hierarchical Path Computation Elements (PCE) Hierarchical Path Computation Elements (PCE)
draft-ietf-pce-hierarchy-extensions-03 draft-ietf-pce-hierarchy-extensions-04
Abstract Abstract
The Hierarchical Path Computation Element (H-PCE) architecture (RFC The Hierarchical Path Computation Element (H-PCE) architecture RFC
6805), provides a mechanism to allow the optimum sequence of domains 6805, provides a mechanism to allow the optimum sequence of domains
to be selected, and the optimum end-to-end path to be derived through to be selected, and the optimum end-to-end path to be derived through
the use of a hierarchical relationship between domains. the use of a hierarchical relationship between domains.
This document defines the Path Computation Element Protocol (PCEP) This document defines the Path Computation Element Protocol (PCEP)
extensions for the purpose of implementing necessary Hierarchical PCE extensions for the purpose of implementing necessary Hierarchical PCE
procedures and protocol extensions. procedures and protocol extensions.
Status of this Memo Status of This Memo
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provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire in January 8, 2017. This Internet-Draft will expire on September 6, 2018.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . .3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . .4 1.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . .4 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
1.3. Requirements Language . . . . . . . . . . . . . . . . . .4 1.3. Requirements Language . . . . . . . . . . . . . . . . . . 5
2. Requirements for H-PCE . . . . . . . . . . . . . . . . . . . .4 2. Requirements for H-PCE . . . . . . . . . . . . . . . . . . . 5
2.1. PCEP Requests . . . . . . . . . . . . . . . . . . . . . .5 2.1. Path Computation Request . . . . . . . . . . . . . . . . 5
2.1.1. Qualification of PCEP Requests . . . . . . . . . . . .5 2.1.1. Qualification of PCEP Requests . . . . . . . . . . . 5
2.1.2. Multi-domain Objective Functions . . . . . . . . . . .5 2.1.2. Multi-domain Objective Functions . . . . . . . . . . 6
2.1.3. Multi-domain Metrics . . . . . . . . . . . . . . . . .6 2.1.3. Multi-domain Metrics . . . . . . . . . . . . . . . . 6
2.2. Parent PCE Capability Discovery . . . . . . . . . . . . .6 2.2. Parent PCE Capability Advertisement . . . . . . . . . . . 7
2.3. PCE Domain and PCE ID Discovery . . . . . . . . . . . . .6 2.3. PCE Domain Discovery . . . . . . . . . . . . . . . . . . 7
3. PCEP Extensions (Encoding) . . . . . . . . . . . . . . . . . .6 2.4. Domain Diversity . . . . . . . . . . . . . . . . . . . . 7
3.1. OPEN Object . . . . . . . . . . . . . . . . . . . . . . .7 3. PCEP Extensions . . . . . . . . . . . . . . . . . . . . . . . 8
3.1.1. H-PCE capability TLV . . . . . . . . . . . . . . . . .7 3.1. OPEN object . . . . . . . . . . . . . . . . . . . . . . . 8
3.1.2. Domain-ID TLV . . . . . . . . . . . . . . . . . . . .8 3.1.1. H-PCE capability TLV . . . . . . . . . . . . . . . . 8
3.2. RP object . . . . . . . . . . . . . . . . . . . . . . . . .9 3.1.2. Domain-ID TLV . . . . . . . . . . . . . . . . . . . . 9
3.2.1. H-PCE-FLAG TLV . . . . . . . . . . . . . . . . . . . .9 3.2. RP object . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2.2. Domain-ID TLV . . . . . . . . . . . . . . . . . . . .9 3.2.1. H-PCE-FLAG TLV . . . . . . . . . . . . . . . . . . . 10
3.3. Objective Function . . . . . . . . . . . . . . . . . . . .10 3.2.2. Domain-ID TLV . . . . . . . . . . . . . . . . . . . . 10
3.3.1. OF Codes . . . . . . . . . . . . . . . . . . . . . . .10 3.3. Objective Functions . . . . . . . . . . . . . . . . . . . 11
3.3.2. OF Object . . . . . . . . . . . . . . . . . . . . . .11 3.3.1. OF Codes . . . . . . . . . . . . . . . . . . . . . . 11
3.4. Metric Object . . . . . . . . . . . . . . . . . . . . . .11 3.3.2. OF Object . . . . . . . . . . . . . . . . . . . . . . 12
3.5. PCEP-ERROR Object . . . . . . . . . . . . . . . . . . . .12 3.4. Metric Object . . . . . . . . . . . . . . . . . . . . . . 12
3.5.1. Hierarchy PCE Error-Type . . . . . . . . . . . . . . .12 3.5. SVEC Object . . . . . . . . . . . . . . . . . . . . . . . 13
3.6. NO-PATH Object . . . . . . . . . . . . . . . . . . . . . .12 3.6. PCEP-ERROR object . . . . . . . . . . . . . . . . . . . . 13
4. H-PCE Procedures . . . . . . . . . . . . . . . . . . . . . . .13 3.6.1. Hierarchy PCE Error-Type . . . . . . . . . . . . . . 13
4.1. OPEN Procedure between Child PCE and Parent PCE . . . . .13 3.7. NO-PATH Object . . . . . . . . . . . . . . . . . . . . . 14
4.2. Procedure to Obtain Domain Sequence . . . . . . . . . . .13 4. H-PCE Procedures . . . . . . . . . . . . . . . . . . . . . . 14
5. Error Handling . . . . . . . . . . . . . . . . . . . . . . . .14 4.1. OPEN Procedure between Child PCE and Parent PCE . . . . . 14
6. Manageability Considerations . . . . . . . . . . . . . . . . .14 4.2. Procedure to obtain Domain Sequence . . . . . . . . . . . 15
6.1. Control of Function and Policy . . . . . . . . . . . . . .15 5. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 15
6.1.1. Child PCE . . . . . . . . . . . . . . . . . . . . . .15 6. Manageability Considerations . . . . . . . . . . . . . . . . 16
6.1.2. Parent PCE . . . . . . . . . . . . . . . . . . . . . .15 6.1. Control of Function and Policy . . . . . . . . . . . . . 16
6.1.3. Policy Control . . . . . . . . . . . . . . . . . . . .15 6.1.1. Child PCE . . . . . . . . . . . . . . . . . . . . . . 17
6.2. Information and Data Models . . . . . . . . . . . . . . .15 6.1.2. Parent PCE . . . . . . . . . . . . . . . . . . . . . 17
6.3. Liveness Detection and Monitoring . . . . . . . . . . . .16 6.1.3. Policy Control . . . . . . . . . . . . . . . . . . . 17
6.4. Verifying Correct Operation . . . . . . . . . . . . . . .16 6.2. Information and Data Models . . . . . . . . . . . . . . . 17
6.5. Impact on Network Operation . . . . . . . . . . . . . . .16 6.3. Liveness Detection and Monitoring . . . . . . . . . . . . 18
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . .16 6.4. Verify Correct Operations . . . . . . . . . . . . . . . . 18
7.1. PCEP TLV . . . . . . . . . . . . . . . . . . . . . . . . .16 6.5. Requirements On Other Protocols . . . . . . . . . . . . . 18
7.2. H-PCE-CAPABILITY TLV Flags . . . . . . . . . . . . . . . .17 6.6. Impact On Network Operations . . . . . . . . . . . . . . 18
7.3. Domain-ID TLV Domain Type . . . . . . . . . . . . . . . .17 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
7.4. H-PCE-FLAG TLV Flags . . . . . . . . . . . . . . . . . . .17 7.1. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . 19
7.5. OF Codes . . . . . . . . . . . . . . . . . . . . . . . . .18 7.2. H-PCE-CAPABILITY TLV Flags . . . . . . . . . . . . . . . 19
7.6. METRIC Types . . . . . . . . . . . . . . . . . . . . . . .18 7.3. Domain-ID TLV Domain type . . . . . . . . . . . . . . . . 19
7.7. New PCEP Error-Types and Values . . . . . . . . . . . . .19 7.4. H-PCE-FLAG TLV Flags . . . . . . . . . . . . . . . . . . 20
7.8. New NO-PATH-VECTOR TLV Bit Flag . . . . . . . . . . . . .19 7.5. OF Codes . . . . . . . . . . . . . . . . . . . . . . . . 20
8. Security Considerations . . . . . . . . . . . . . . . . . . . 20 7.6. METRIC Types . . . . . . . . . . . . . . . . . . . . . . 21
9. Implementation Status . . . . . . . . . . . . . . . . . . . .20 7.7. New PCEP Error-Types and Values . . . . . . . . . . . . . 21
9.1. Inter-layer traffic engineering with H-PCE. . . . . . . . .21 7.8. New NO-PATH-VECTOR TLV Bit Flag . . . . . . . . . . . . . 22
9.2. Telefonica Netphony (Open Source PCE) . . . . . . . . . . .21 7.9. SVEC Flag . . . . . . . . . . . . . . . . . . . . . . . . 22
9.3. H-PCE Proof of Concept developed by Huawei. . . . . . . . .23 8. Security Considerations . . . . . . . . . . . . . . . . . . . 22
10. Contributing Authors . . . . . . . . . . . . . . . . . . . .23 9. Implementation Status . . . . . . . . . . . . . . . . . . . . 23
11. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . 23 9.1. Inter-layer traffic engineering with H-PCE . . . . . . . 23
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 23 9.2. Telefonica Netphony (Open Source PCE) . . . . . . . . . . 24
12.1. Normative References. . . . . . . . . . . . . . . . . . . 23 9.3. Implementation 3: H-PCE Proof of Concept developed by
12.2. Informative References. . . . . . . . . . . . . . . . . . 24 Huawei . . . . . . . . . . . . . . . . . . . . . . . . . 26
10. Contributing Authors . . . . . . . . . . . . . . . . . . . . 26
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 26
11.1. Normative References . . . . . . . . . . . . . . . . . . 27
11.2. Informative References . . . . . . . . . . . . . . . . . 27
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29
1. Introduction 1. Introduction
[RFC6805] describes a Hierarchical PCE (H-PCE) architecture which can [RFC6805] describes a Hierarchical PCE (H-PCE) architecture which can
be used for computing end-to-end paths for inter-domain MPLS Traffic be used for computing end-to-end paths for inter-domain MPLS Traffic
Engineering (TE) and GMPLS Label Switched Paths (LSPs). Engineering (TE) and GMPLS Label Switched Paths (LSPs).
Within the hierarchical PCE architecture, the parent PCE is used to Within the hierarchical PCE architecture, the parent PCE is used to
compute a multi-domain path based on the domain connectivity compute a multi-domain path based on the domain connectivity
information . A child PCE may be responsible for a single domain or information . A child PCE may be responsible for a single domain or
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This document defines the PCEP extensions for the purpose of This document defines the PCEP extensions for the purpose of
implementing Hierarchical PCE procedures, which are described in implementing Hierarchical PCE procedures, which are described in
[RFC6805]. [RFC6805].
1.1. Scope 1.1. Scope
The following functions are out of scope of this document. The following functions are out of scope of this document.
o Determination of Destination Domain (section 4.5 of [RFC6805]) o Determination of Destination Domain (section 4.5 of [RFC6805])
- via collection of reachability information from child domain; * via collection of reachability information from child domain;
- via requests to the child PCEs to discover if they contain the * via requests to the child PCEs to discover if they contain the
destination node; destination node;
- or any other methods. * or any other methods.
o Parent Traffic Engineering Database (TED) methods (section 4.4 of o Parent Traffic Engineering Database (TED) methods (section 4.4 of
[RFC6805]) [RFC6805])
o Learning of Domain connectivity and boundary nodes (BN) addresses. o Learning of Domain connectivity and boundary nodes (BN) addresses.
1.2. Terminology 1.2. Terminology
This document uses the terminology defined in [RFC4655], [RFC5440] This document uses the terminology defined in [RFC4655], [RFC5440]
and the additional terms defined in section 1.4 of [RFC6805]. and the additional terms defined in section 1.4 of [RFC6805].
1.3. Requirements Language 1.3. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
document are to be interpreted as described in [RFC2119]. "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. Requirements for H-PCE 2. Requirements for H-PCE
This section compiles the set of requirements of the PCEP protocol to This section compiles the set of requirements of the PCEP protocol to
support the H-PCE architecture and procedures. support the H-PCE architecture and procedures.
[RFC6805] identifies high-level requirements of PCEP extensions [RFC6805] identifies high-level requirements of PCEP extensions
required to support the hierarchical PCE model. required to support the hierarchical PCE model.
2.1. Path Computation Request 2.1. Path Computation Request
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2.1.2. Multi-domain Objective Functions 2.1.2. Multi-domain Objective Functions
For inter-domain path computation, there is one new objective For inter-domain path computation, there is one new objective
Function which is defined in section 1.3.1 and 4.1 of [RFC6805]: Function which is defined in section 1.3.1 and 4.1 of [RFC6805]:
o Minimize the number of domains crossed. A domain can be either an o Minimize the number of domains crossed. A domain can be either an
Autonomous System (AS) or an Internal Gateway Protocol (IGP) area Autonomous System (AS) or an Internal Gateway Protocol (IGP) area
depending on the type of multi-domain network hierarchical PCE is depending on the type of multi-domain network hierarchical PCE is
applied to. applied to.
Another objective Function to minimize the number of border nodes is
also defined in this document.
During the PCEP session establishment procedure, the parent PCE needs During the PCEP session establishment procedure, the parent PCE needs
to be capable of indicating the Objective Functions (OF) [RFC5541] to be capable of indicating the Objective Functions (OF) [RFC5541]
capability in the Open message. This capability information may then capability in the Open message. This capability information may then
be announced by child PCEs, and used for selecting the PCE when a PCC be announced by child PCEs, and used for selecting the PCE when a PCC
wants a path that satisfies one or multiple inter-domain objective wants a path that satisfies one or multiple inter-domain objective
functions. functions.
When a PCC requests a PCE to compute an inter-domain path, the PCC When a PCC requests a PCE to compute an inter-domain path, the PCC
needs also to be capable of indicating the new objective functions needs also to be capable of indicating the new objective functions
for inter-domain path. Note that a given child PCE may also act as a for inter-domain path. Note that a given child PCE may also act as a
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For the reasons described previously, new OF codes need to be defined For the reasons described previously, new OF codes need to be defined
for the new inter-domain objective functions. Then the PCE can for the new inter-domain objective functions. Then the PCE can
notify its new inter-domain objective functions to the PCC by notify its new inter-domain objective functions to the PCC by
carrying them in the OF-list TLV which is carried in the OPEN object. carrying them in the OF-list TLV which is carried in the OPEN object.
The PCC can specify which objective function code to use, which is The PCC can specify which objective function code to use, which is
carried in the OF object when requesting a PCE to compute an inter- carried in the OF object when requesting a PCE to compute an inter-
domain path. domain path.
A parent PCE MUST be capable of ensuring homogeneity, across domains, A parent PCE MUST be capable of ensuring homogeneity, across domains,
when applying OF codes for strict OF intra-domain requests . when applying OF codes for strict OF intra-domain requests.
2.1.3. Multi-domain Metrics 2.1.3. Multi-domain Metrics
For inter-domain path computation, there are several path metrics of For inter-domain path computation, there are several path metrics of
Interest. interest.
o Domain count (number of domains crossed); o Domain count (number of domains crossed);
o Border Node count. o Border Node count.
A PCC may be able to limit the number of domains crossed by applying A PCC may be able to limit the number of domains crossed by applying
a limit on these metrics. Details in section 3.3. a limit on these metrics. Details in section 3.3.
2.2. Parent PCE Capability Advertisement 2.2. Parent PCE Capability Advertisement
Parent and child PCE relationships are likely to be configured. Parent and child PCE relationships are likely to be configured.
However, as mentioned in [RFC6805], it would assist network operators However, as mentioned in [RFC6805], it would assist network operators
if the child and parent PCEs could indicate their H-PCE capabilities. if the child and parent PCEs could indicate their H-PCE capabilities.
During the PCEP session establishment procedure, the child PCE needs During the PCEP session establishment procedure, the child PCE needs
to be capable of indicating to the parent PCE whether it requests the to be capable of indicating to the parent PCE whether it requests the
parent PCE capability or not. Also, during the PCEP session parent PCE capability or not. Also, during the PCEP session
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to be capable of indicating to the parent PCE whether it requests the to be capable of indicating to the parent PCE whether it requests the
parent PCE capability or not. Also, during the PCEP session parent PCE capability or not. Also, during the PCEP session
establishment procedure, the parent PCE needs to be capable of establishment procedure, the parent PCE needs to be capable of
indicating whether its parent capability can be provided or not. indicating whether its parent capability can be provided or not.
A PCEP Speaker (Parent PCE or Child PCE or PCC) includes the "H-PCE A PCEP Speaker (Parent PCE or Child PCE or PCC) includes the "H-PCE
Capability" TLV, described in Section 3.1.1, in the OPEN Object to Capability" TLV, described in Section 3.1.1, in the OPEN Object to
advertise its support for PCEP extensions for H-PCE Capability. advertise its support for PCEP extensions for H-PCE Capability.
2.3. PCE Domain Discovery 2.3. PCE Domain Discovery
A PCE domain is a single domain with an associated PCE. Although it A PCE domain is a single domain with an associated PCE. Although it
is possible for a PCE to manage multiple domains. The PCE domain may is possible for a PCE to manage multiple domains. The PCE domain may
be an IGP area or AS. be an IGP area or AS.
The PCE domain identifiers may be provided during the PCEP session The PCE domain identifiers may be provided during the PCEP session
establishment procedure. establishment procedure.
2.4. Domain Diversity
In a multi-domain environment, Domain Diversity is defined in
[RFC6805]. A pair of paths are domain-diverse if they do not
traverse any of the same transit domains. Domain diversity may be
maximized for a pair of paths by selecting paths that have the
smallest number of shared domains. Path computation should
facilitate the selection of domain diverse paths as a way to reduce
the risk of shared failure and automatically helps to ensure path
diversity for most of the route of a pair of LSPs.
The main motivation behind domain diversity is to avoid fate sharing,
but it can also be because of some geo-political reasons and
commercial relationships that would require domain diversity. for
example, a pair of paths should choose different transit Autonomous
System (AS) because of some policy considerations.
In case when full domain diversity could not be achieved, it is
helpful to minimize the common shared domains. Also it is
interesting to note that other scope of diversity (node, link, SRLG
etc) can still be applied inside the common shared domains.
3. PCEP Extensions 3. PCEP Extensions
This section defines PCEP extensions to ([RFC5440]) so as to This section defines PCEP extensions to ([RFC5440]) so as to support
support the H-PCE procedures. the H-PCE procedures.
3.1. OPEN object 3.1. OPEN object
Two new TLVs are defined in this document to be carried within an Two new TLVs are defined in this document to be carried within an
OPEN object. This way, during PCEP session establishment, the H-PCE OPEN object. This way, during PCEP session establishment, the H-PCE
capability and Domain information can be advertised. capability and Domain information can be advertised.
3.1.1. H-PCE capability TLV 3.1.1. H-PCE capability TLV
The H-PCE-CAPABILITY TLV is an optional TLV associated with the OPEN The H-PCE-CAPABILITY TLV is an optional TLV associated with the OPEN
Object [RFC5440] to exchange H-PCE capability of PCEP speakers. Object [RFC5440] to exchange H-PCE capability of PCEP speakers.
Its format is shown in the following figure: Its format is shown in the following figure:
0 1 2 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 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= TBD1 | Length=4 | | Type= TBD1 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags |I|R| | Flags |I|R|
+---------------------------------------------------------------+ +---------------------------------------------------------------+
Figure 1: H-PCE-CAPABILITY TLV format
Figure 1: H-PCE-CAPABILITY TLV format
The type of the TLV is TBD1 (to be assigned by IANA) and it has a The type of the TLV is TBD1 (to be assigned by IANA) and it has a
fixed length of 4 octets. fixed length of 4 octets.
The value comprises a single field - Flags (32 bits): The value comprises a single field - Flags (32 bits):
R (Parent PCE Request bit): if set, will signal that the child R (Parent PCE Request bit): if set, will signal that the child PCE
PCE wishes to use the peer PCE as a parent PCE. wishes to use the peer PCE as a parent PCE.
I (Parent PCE Indication bit): if set, will signal that the PCE can I (Parent PCE Indication bit): if set, will signal that the PCE
be used as a parent PCE by the peer PCE. can be used as a parent PCE by the peer PCE.
The inclusion of this TLV in an OPEN object indicate that the H-PCE The inclusion of this TLV in an OPEN object indicate that the H-PCE
extensions are supported by the PCEP speaker. The PCC MAY include extensions are supported by the PCEP speaker. The PCC MAY include
this TLV to indicate that it understands the H-PCE extensions. The this TLV to indicate that it understands the H-PCE extensions. The
Child PCE MUST include this TLV and set the R flag (and unset the I Child PCE MUST include this TLV and set the R flag (and unset the I
flag) on the PCEP session towards the Parent PCE. The Parent PCE MUST flag) on the PCEP session towards the Parent PCE. The Parent PCE
include this TLV and set the I flag and unset the R flag on the MUST include this TLV and set the I flag and unset the R flag on the
PCEP session towards the child PCE. The parent-child PCEP session is PCEP session towards the child PCE. The parent-child PCEP session is
set to be established only when this capability is advertised. set to be established only when this capability is advertised.
If such capability is not exchanged and the parent PCE receive a "H- If such capability is not exchanged and the parent PCE receive a "H-
PCE path computation request", it MUST send a PCErr message with PCE path computation request", it MUST send a PCErr message with
Error-Type=TBD8 (H-PCE error) and Error-Value=1 (Parent PCE Error-Type=TBD8 (H-PCE error) and Error-Value=1 (Parent PCE
Capability not advertised). Capability not advertised).
3.1.2. Domain-ID TLV 3.1.2. Domain-ID TLV
The Domain-ID TLV when used in OPEN object identify the domain(s) The Domain-ID TLV when used in OPEN object identify the domain(s)
served by the PCE. The child PCE uses this mechanism to inform the served by the PCE. The child PCE uses this mechanism to inform the
domain information to the parent PCE. domain information to the parent PCE.
The Domain-ID TLV is defined below: The Domain-ID TLV is defined below:
0 1 2 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 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type= TBD2 | Length | | Type= TBD2 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Domain Type | Reserved | | Domain Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Domain ID | | Domain ID |
// // // //
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Domain-ID TLV format Figure 2: Domain-ID TLV format
The type of the TLV is TBD2 (to be assigned by IANA) and it has a The type of the TLV is TBD2 (to be assigned by IANA) and it has a
variable Length of the value portion. The value part comprises of - variable Length of the value portion. The value part comprises of -
Domain Type (8 bits): Indicates the domain type. Four types of Domain Type (8 bits): Indicates the domain type. Four types of
domain are currently defined: domain are currently defined:
o Type=1: the Domain ID field carries a 2-byte AS number. Padded * Type=1: the Domain ID field carries a 2-byte AS number. Padded
with trailing zeroes to a 4-byte boundary. with trailing zeroes to a 4-byte boundary.
o Type=2: the Domain ID field carries a 4-byte AS number. * Type=2: the Domain ID field carries a 4-byte AS number.
o Type=3: the Domain ID field carries an 4-byte OSPF area ID. * Type=3: the Domain ID field carries an 4-byte OSPF area ID.
o Type=4: the Domain ID field carries <2-byte Area-Len, variable * Type=4: the Domain ID field carries [2-byte Area-Len, variable
length IS-IS area ID>. Padded with trailing zeroes to a 4-byte length IS-IS area ID]. Padded with trailing zeroes to a 4-byte
boundary. boundary.
Reserved: Zero at transmission; ignored at receipt. Reserved: Zero at transmission; ignored at receipt.
Domain ID (variable): Indicates an IGP Area ID or AS number. It can Domain ID (variable): Indicates an IGP Area ID or AS number. It
be 2 bytes, 4 bytes or variable length depending on the domain can be 2 bytes, 4 bytes or variable length depending on the domain
identifier used. It is padded with trailing zeroes to a 4-byte identifier used. It is padded with trailing zeroes to a 4-byte
boundary . boundary.
In case a PCE serves more than one domain, multiple Domain-ID TLV is In case a PCE serves more than one domain, multiple Domain-ID TLV is
included for each domain it serves. included for each domain it serves.
3.2. RP object 3.2. RP object
3.2.1. H-PCE-FLAG TLV 3.2.1. H-PCE-FLAG TLV
The H-PCE-FLAG TLV is an optional TLV associated with the RP Object The H-PCE-FLAG TLV is an optional TLV associated with the RP Object
[RFC5440] to indicate the H-PCE path computation request and [RFC5440] to indicate the H-PCE path computation request and options.
options..
Its format is shown in the following figure: Its format is shown in the following figure:
0 1 2 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 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= TBD3 | Length=4 | | Type= TBD3 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags |D|S| | Flags |D|S|
+---------------------------------------------------------------+ +---------------------------------------------------------------+
Figure 3: H-PCE-FLAG TLV format
Figure 3: H-PCE-FLAG TLV format
The type of the TLV is TBD3 (to be assigned by IANA) and it has a The type of the TLV is TBD3 (to be assigned by IANA) and it has a
fixed length of 4 octets. fixed length of 4 octets.
The value comprises a single field - Flags (32 bits): The value comprises a single field - Flags (32 bits):
S (Domain Sequence bit): if set, will signal that the child PCE S (Domain Sequence bit): if set, will signal that the child PCE
wishes to get only the domain sequence in the path computation reply. wishes to get only the domain sequence in the path computation
reply. Refer section 3.7 of [RFC7897] for details.
D (Disallow Domain Re-entry bit): if set, will signal that the D (Disallow Domain Re-entry bit): if set, will signal that the
computed path does not enter a domain more than once. computed path does not enter a domain more than once.
3.2.2. Domain-ID TLV 3.2.2. Domain-ID TLV
The usage of Domain-ID TLV carried in an OPEN object is used to The usage of Domain-ID TLV carried in an OPEN object is used to
indicate a (list of) managed domains and is described in section indicate a (list of) managed domains and is described in section
3.1.2. This TLV when carried in a RP object, indicates the 3.1.2. This TLV when carried in a RP object, indicates the
destination domain ID. If a PCC knows the egress domain, it can destination domain ID. If a PCC knows the egress domain, it can
supply this information in the PCReq message. The format of this supply this information in the PCReq message. The format of this TLV
TLV is defined in Section 3.1.2. is defined in Section 3.1.2.
3.3. Objective Functions 3.3. Objective Functions
3.3.1. OF Codes 3.3.1. OF Codes
[RFC5541] defines a mechanism to specify an objective function that [RFC5541] defines a mechanism to specify an objective function that
is used by a PCE when it computes a path. Two new objective functions is used by a PCE when it computes a path. Two new objective
are defined for the H-PCE experiment. functions are defined for the H-PCE experiment.
o MTD o MTD
* Name: Minimize the number of Transit Domains (MTD) * Name: Minimize the number of Transit Domains (MTD)
* Objective Function Code - TBD4 (to be assigned by IANA) * Objective Function Code - TBD4 (to be assigned by IANA)
* Description: Find a path P such that it passes through the * Description: Find a path P such that it passes through the
least number of transit domains. least number of transit domains.
Objective functions are formulated using the following terminology: * Objective functions are formulated using the following
terminology:
- A network comprises a set of N domains {Di, (i=1...N)}. + A network comprises a set of N domains {Di, (i=1...N)}.
- A path P passes through K domains {Dpi,(i=1...K)}. + A path P passes through K domains {Dpi,(i=1...K)}.
Find a path P such that the value of K is minimized. + Find a path P such that the value of K is minimized.
o MBN o MBN
* Name: Minimize the number of border nodes. * Name: Minimize the number of border nodes.
* Objective Function Code - TBD5 (to be assigned by IANA) * Objective Function Code - TBD5 (to be assigned by IANA)
* Description: Find a path P such that it passes through the * Description: Find a path P such that it passes through the
least number of border nodes. least number of border nodes.
Objective functions are formulated using the following * Objective functions are formulated using the following
terminology: terminology:
- A network comprises a set of N nodes {Ni, (i=1...N)}. + A network comprises a set of N nodes {Ni, (i=1...N)}.
- A path P is a list of K nodes {Npi,(i=1...K)}. + A path P is a list of K nodes {Npi,(i=1...K)}.
- B(N) if a function that determine if the node is a border node. + B(N) if a function that determine if the node is a border
B(Ni) = 1 if Ni is border node; B(Nk) = 0 if Nk is not a border node. B(Ni) = 1 if Ni is border node; B(Nk) = 0 if Nk is
node. not a border node.
- The number of border node in a path P is denoted by B(P), where + The number of border node in a path P is denoted by B(P),
B(P) = sum{B(Npi),(i=1...K)}. where B(P) = sum{B(Npi),(i=1...K)}.
Find a path P such that B(P) is minimized. + Find a path P such that B(P) is minimized.
MCTD
o Name: Minimize the number of Common Transit Domains.
o Objective Function Code: TBD13
o Description: Find a set of paths such that it passes through the
least number of common transit domains.
3.3.2. OF Object 3.3.2. OF Object
The OF (Objective Function) object [RFC5541] is carried within a The OF (Objective Function) object [RFC5541] is carried within a
PCReq message so as to indicate the desired/required objective PCReq message so as to indicate the desired/required objective
function to be applied by the PCE during path computation. As per function to be applied by the PCE during path computation. As per
section 3.2 of [RFC5541] a single OF object may be included in section 3.2 of [RFC5541] a single OF object may be included in a path
a path computation request. computation request.
The new OF code described in section 3.3.1 are applicable at the The new OF code described in section 3.3.1 are applicable at the
inter-domain level (parent), it is also necessary to specify the OF inter-domain level (parent), it is also necessary to specify the OF
code that may be applied at the intra-domain (child) path computation code that may be applied at the intra-domain (child) path computation
level. To accommodate this, the OF-List TLV (described in section level. To accommodate this, the OF-List TLV (described in section
2.1. of [RFC5541]) is included in the OF object as an optional TLV. 2.1. of [RFC5541]) is included in the OF object as an optional TLV.
OF-List TLV allow encoding of multiple OF codes. When this TLV is OF-List TLV allow encoding of multiple OF codes. When this TLV is
included inside the OF object, only the first OF-code in the OF-LIST included inside the OF object, only the first OF-code in the OF-LIST
TLV is considered. The parent PCE would use this OF code in the OF TLV is considered. The parent PCE would use this OF code in the OF
object when sending the intra domain path computation request to the object when sending the intra domain path computation request to the
child PCE . child PCE.
If the objective functions defined in this document are unknown/ If the objective functions defined in this document are unknown/
unsupported by a PCE, then the procedure as defined in [RFC5541] is unsupported by a PCE, then the procedure as defined in [RFC5541] is
followed. followed.
3.4. Metric Object 3.4. Metric Object
The METRIC object is defined in section 7.8 of [RFC5440], comprising The METRIC object is defined in section 7.8 of [RFC5440], comprising
metric-value, metric-type (T field) and flags. This document defines metric-value, metric-type (T field) and flags. This document defines
the following types for the METRIC object for H-PCE: the following types for the METRIC object for H-PCE:
o T=TBD6: Domain count metric (number of domains crossed); o T=TBD6: Domain count metric (number of domains crossed);
o T=TBD7: Border Node count metric (number of border nodes crossed). o T=TBD7: Border Node count metric (number of border nodes crossed).
The domain count metric type of the METRIC object encodes the number The domain count metric type of the METRIC object encodes the number
of domain crossed in the path. The border node count metric type of of domain crossed in the path. The border node count metric type of
the METRIC object encodes the number of border nodes in the path. the METRIC object encodes the number of border nodes in the path.
A PCC or child PCE MAY use these metric in PCReq message an inter- A PCC or child PCE MAY use these metric in PCReq message an inter-
domain path meeting the number of domain or border nodes requirement. domain path meeting the number of domain or border nodes requirement.
In this case, the B bit MUST be set to suggest a bound (a maximum) In this case, the B bit MUST be set to suggest a bound (a maximum)
for the metric that must not be exceeded for the PCC to consider the for the metric that must not be exceeded for the PCC to consider the
computed path as acceptable. computed path as acceptable.
A PCC or child PCE MAY also use this metric to ask the PCE to A PCC or child PCE MAY also use this metric to ask the PCE to
optimize the metric during inter-domain path computation. In this optimize the metric during inter-domain path computation. In this
case, the B flag MUST be cleared. case, the B flag MUST be cleared.
The Parent PCE MAY use these metric in a PCRep message along with a The Parent PCE MAY use these metric in a PCRep message along with a
NO-PATH object in the case where the PCE cannot compute a path NO-PATH object in the case where the PCE cannot compute a path
meeting this constraint. A PCE MAY also use this metric to send the meeting this constraint. A PCE MAY also use this metric to send the
computed end to end metric in a reply message. computed end to end metric in a reply message.
3.5. PCEP-ERROR object 3.5. SVEC Object
3.5.1. Hierarchy PCE Error-Type [RFC5440] defines SVEC object which includes flags for the potential
dependency between the set of path computation requests (Link, Node
and SRLG diverse). This document proposes a new flag O for domain
diversity.
Following new bit is added in the Flags field:
o O (Domain diverse) bit - TBD12 : when set, this indicates that the
computed paths corresponding to the requests specified by the
following RP objects MUST NOT have any transit domain(s) in
common.
The Domain Diverse O-bit can be used in Hierarchical PCE path
computation to compute synchronized domain diverse end to end path or
diverse domain sequences.
When domain diverse O bit is set, it is applied to the transit
domains. The other bit in SVEC object (N, L, S etc) is set, SHOULD
still be applied in the ingress and egress shared domain.
3.6. PCEP-ERROR object
3.6.1. Hierarchy PCE Error-Type
A new PCEP Error-Type is used for this H-PCE experiment and is A new PCEP Error-Type is used for this H-PCE experiment and is
defined below: defined below:
+------------+------------------------------------------------------+ +------------+------------------------------------------------------+
| Error-Type | Meaning | | Error-Type | Meaning |
+------------+------------------------------------------------------+ +------------+------------------------------------------------------+
| TBD8 | H-PCE error | | TBD8 | H-PCE error |
| | Error-value=1: parent PCE capability | | | Error-value=1: parent PCE capability |
| | was not advertised | | | was not advertised |
| | Error-value=2: parent PCE capability | | | Error-value=2: parent PCE capability |
| | cannot be provided | | | cannot be provided |
+------------+------------------------------------------------------+ +------------+------------------------------------------------------+
Figure 4: H-PCE error Figure 4: H-PCE error
3.6. NO-PATH Object 3.7. NO-PATH Object
To communicate the reason(s) for not being able to find a multi- To communicate the reason(s) for not being able to find a multi-
domain path or domain sequence, the NO-PATH object can be used in the domain path or domain sequence, the NO-PATH object can be used in the
PCRep message. [RFC5440] defines the format of the NO-PATH object. PCRep message. [RFC5440] defines the format of the NO-PATH object.
The object may contain a NO-PATH-VECTOR TLV to provide additional The object may contain a NO-PATH-VECTOR TLV to provide additional
information about why a path computation has failed. information about why a path computation has failed.
Three new bit flags are defined to be carried in the Flags field in Three new bit flags are defined to be carried in the Flags field in
the NO-PATH-VECTOR TLV carried in the NO-PATH Object. the NO-PATH-VECTOR TLV carried in the NO-PATH Object.
o Bit number TBD9: When set, the parent PCE indicates that o Bit number TBD9: When set, the parent PCE indicates that
destination domain unknown; destination domain unknown;
o Bit number TBD10: When set, the parent PCE indicates unresponsive o Bit number TBD10: When set, the parent PCE indicates unresponsive
child PCE(s); child PCE(s);
o Bit number TBD11: When set, the parent PCE indicates no available o Bit number TBD11: When set, the parent PCE indicates no available
resource available in one or more domain(s). resource available in one or more domain(s).
4. H-PCE Procedures 4. H-PCE Procedures
4.1. OPEN Procedure between Child PCE and Parent PCE 4.1. OPEN Procedure between Child PCE and Parent PCE
If a child PCE wants to use the peer PCE as a parent, it can set the If a child PCE wants to use the peer PCE as a parent, it can set the
R (parent PCE request flag) in the H-PCE-CAPABILITY TLV inside the R (parent PCE request flag) in the H-PCE-CAPABILITY TLV inside the
OPEN object carried in the Open message OPEN object carried in the Open message during the PCEP session
during the PCEP session creation procedure. creation procedure.
If the parent PCE can provide the parent function to the peer PCE, it If the parent PCE can provide the parent function to the peer PCE, it
may set the I (parent PCE indication flag) in the H-PCE-CAPABILITY may set the I (parent PCE indication flag) in the H-PCE-CAPABILITY
TLV inside the OPEN object carried in TLV inside the OPEN object carried in the Open message during the
the Open message during the PCEP session creation procedure. PCEP session creation procedure.
The PCE may also report its list of domain IDs to the peer The PCE may also report its list of domain IDs to the peer PCE by
PCE by specifying them in the Domain-ID TLVs in the OPEN object specifying them in the Domain-ID TLVs in the OPEN object carried in
carried in the Open message during the PCEP session creation the Open message during the PCEP session creation procedure.
procedure.
The OF codes defined in this document can be carried in the OF-list The OF codes defined in this document can be carried in the OF-list
TLV of the OPEN object. If the OF-list TLV carries the OF codes, it TLV of the OPEN object. If the OF-list TLV carries the OF codes, it
means that the PCE is capable of implementing the corresponding means that the PCE is capable of implementing the corresponding
objective functions. This information can be used for selecting a objective functions. This information can be used for selecting a
proper parent PCE when a child PCE wants to get a path that satisfies proper parent PCE when a child PCE wants to get a path that satisfies
a certain objective function. a certain objective function.
When a specific child PCE sends a PCReq to a peer PCE that requires When a specific child PCE sends a PCReq to a peer PCE that requires
parental activity and H-PCE capability flags were not set in the parental activity and H-PCE capability flags were not set in the
session establishment procedure as described above, the peer PCE session establishment procedure as described above, the peer PCE
should send a PCErr message to the child PCE and should send a PCErr message to the child PCE and specify the error-
specify the error-type=TBD (H-PCE error) and error-value=1 (parent type=TBD (H-PCE error) and error-value=1 (parent PCE capability was
PCE capability was not advertised) in the PCEP-ERROR object. not advertised) in the PCEP-ERROR object.
When a specific child PCE sends a PCReq to a peer PCE that requires When a specific child PCE sends a PCReq to a peer PCE that requires
parental activity and the peer PCE does not want to act as the parent parental activity and the peer PCE does not want to act as the parent
for it, the peer PCE should send a PCErr message to the child PCE and for it, the peer PCE should send a PCErr message to the child PCE and
specify the error-type=TBD (H-PCE error) and error-value=2 (parent specify the error-type=TBD (H-PCE error) and error-value=2 (parent
PCE capability cannot be provided) in the PCEP-ERROR object. PCE capability cannot be provided) in the PCEP-ERROR object.
4.2. Procedure to obtain Domain Sequence 4.2. Procedure to obtain Domain Sequence
If a child PCE only wants to get the domain sequence for a multi- If a child PCE only wants to get the domain sequence for a multi-
domain path computation from a parent PCE, it can set the Domain Path domain path computation from a parent PCE, it can set the Domain Path
Request bit in the H-PCE FlagH-PCE-FLAG TLV in the RP object carried Request bit in the H-PCE-FLAG TLV in the RP object carried in a PCReq
in a PCReq message. The parent PCE which receives the PCReq message message. The parent PCE which receives the PCReq message tries to
tries to compute a domain sequence for it. If the domain path compute a domain sequence for it (instead for E2E path). If the
computation succeeds the parent PCE sends a PCRep message which domain path computation succeeds the parent PCE sends a PCRep message
carries the domain sequence in the ERO to the child PCE. Refer which carries the domain sequence in the ERO to the child PCE. Refer
[RFC7897] for more details about domain sub-objects in the ERO. [RFC7897] for more details about domain sub-objects in the ERO.
Otherwise it sends a PCReq message which carries the NO-PATH object Otherwise it sends a PCReq message which carries the NO-PATH object
to the child PCE. to the child PCE.
5. Error Handling 5. Error Handling
A PCE that is capable of acting as a parent PCE might not be A PCE that is capable of acting as a parent PCE might not be
configured or willing to act as the parent for a specific child PCE. configured or willing to act as the parent for a specific child PCE.
This fact could be determined when the child sends a PCReq that This fact could be determined when the child sends a PCReq that
requires parental activity, and could result in a negative response requires parental activity, and could result in a negative response
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In this case, the parent PCE MAY need to send a negative path In this case, the parent PCE MAY need to send a negative path
computation reply specifying the reason. This can be achieved by computation reply specifying the reason. This can be achieved by
including NO-PATH object in the PCRep message. Extension to NO-PATH including NO-PATH object in the PCRep message. Extension to NO-PATH
object is needed to include the aforementioned reasons described in object is needed to include the aforementioned reasons described in
section 3.6. section 3.6.
6. Manageability Considerations 6. Manageability Considerations
General PCE and PCEP management considerations are discussed in General PCE and PCEP management considerations are discussed in
[RFC4655] and [RFC5440]. There are additional management [RFC4655] and [RFC5440]. There are additional management
considerations for H-PCE which are described in [RFC6805], and considerations for H-PCE which are described in [RFC6805], and
repeated in this section. repeated in this section.
The administrative entity responsible for the management of the The administrative entity responsible for the management of the
parent PCEs must be determined for the following cases: parent PCEs must be determined for the following cases:
o multi-domains (e.g., IGP areas or multiple ASes) within a single o multi-domains (e.g., IGP areas or multiple ASes) within a single
service provider network, the management responsibility for the service provider network, the management responsibility for the
parent PCE would most likely be handled by the service provider, parent PCE would most likely be handled by the service provider,
o multiple ASes within different service provider networks, it may o multiple ASes within different service provider networks, it may
be necessary for a third party to manage the parent PCEs according be necessary for a third party to manage the parent PCEs according
to commercial and policy agreements from each of the participating to commercial and policy agreements from each of the participating
service providers. service providers.
6.1. Control of Function and Policy 6.1. Control of Function and Policy
Control and function will need to be carefully managed in a H-PCE Control and function will need to be carefully managed in a H-PCE
network. A child PCE will need to be configured with the network. A child PCE will need to be configured with the address of
address of its parent PCE. It is expected that there will only be its parent PCE. It is expected that there will only be one or two
one or two parents of any child. parents of any child.
The parent PCE also needs to be aware of the child PCEs for all child The parent PCE also needs to be aware of the child PCEs for all child
domains that it can see. This information is most likely to be domains that it can see. This information is most likely to be
configured (as part of the administrative definition of each domain). configured (as part of the administrative definition of each domain).
Discovery of the relationships between parent PCEs and child PCEs Discovery of the relationships between parent PCEs and child PCEs
does not form part of the hierarchical PCE architecture. Mechanisms does not form part of the hierarchical PCE architecture. Mechanisms
that rely on advertising or querying PCE locations across domain or that rely on advertising or querying PCE locations across domain or
provider boundaries are undesirable for security, scaling, provider boundaries are undesirable for security, scaling,
commercial, and confidentiality reasons. commercial, and confidentiality reasons. Specific behavior of the
Specific behavior of the child and parent PCE are described in the child and parent PCE are described in the following sub-sections.
following sub-sections.
6.1.1. Child PCE 6.1.1. Child PCE
Support of the hierarchical procedure will be controlled by the Support of the hierarchical procedure will be controlled by the
management organization responsible for each child PCE. A child management organization responsible for each child PCE. A child PCE
PCE must be configured with the address of its parent PCE in order must be configured with the address of its parent PCE in order for it
for it to interact with its parent PCE. The child PCE must also to interact with its parent PCE. The child PCE must also be
be authorized to peer with the parent PCE. authorized to peer with the parent PCE.
6.1.2. Parent PCE 6.1.2. Parent PCE
The parent PCE must only accept path computation requests from The parent PCE must only accept path computation requests from
authorized child PCEs. If a parent PCE receives requests from an authorized child PCEs. If a parent PCE receives requests from an
unauthorized child PCE, the request should be dropped. This means unauthorized child PCE, the request should be dropped. This means
that a parent PCE must be configured with the identities and that a parent PCE must be configured with the identities and security
security credentials of all of its child PCEs, or there must be credentials of all of its child PCEs, or there must be some form of
some form of shared secret that allows an unknown child PCE to be shared secret that allows an unknown child PCE to be authorized by
authorized by the parent PCE. the parent PCE.
6.1.3. Policy Control 6.1.3. Policy Control
It may be necessary to maintain a policy module on the parent PCE It may be necessary to maintain a policy module on the parent PCE
[RFC5394]. This would allow the parent PCE to apply commercially [RFC5394]. This would allow the parent PCE to apply commercially
relevant constraints such as SLAs, security, peering preferences, and relevant constraints such as SLAs, security, peering preferences, and
monetary costs. monetary costs.
It may also be necessary for the parent PCE to limit end-to-end path It may also be necessary for the parent PCE to limit end-to-end path
selection by including or excluding specific domains based on selection by including or excluding specific domains based on
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It may be necessary to maintain a policy module on the parent PCE It may be necessary to maintain a policy module on the parent PCE
[RFC5394]. This would allow the parent PCE to apply commercially [RFC5394]. This would allow the parent PCE to apply commercially
relevant constraints such as SLAs, security, peering preferences, and relevant constraints such as SLAs, security, peering preferences, and
monetary costs. monetary costs.
It may also be necessary for the parent PCE to limit end-to-end path It may also be necessary for the parent PCE to limit end-to-end path
selection by including or excluding specific domains based on selection by including or excluding specific domains based on
commercial relationships, security implications, and reliability. commercial relationships, security implications, and reliability.
6.2. Information and Data Models 6.2. Information and Data Models
A MIB module for PCEP was published as RFC 7420 [RFC7420] that A MIB module for PCEP was published as RFC 7420 [RFC7420] that
describes managed objects for modeling of PCEP communication. A describes managed objects for modeling of PCEP communication. A YANG
YANG module for PCEP has also been proposed [I-D.pkd-pce-pcep-yang]. module for PCEP has also been proposed [I-D.ietf-pce-pcep-yang].
A H-PCE MIB module, or additional data model, will be required to A H-PCE MIB module, or additional data model, will be required to
report parent PCE and child PCE information, including: report parent PCE and child PCE information, including:
o parent PCE configuration and status, o parent PCE configuration and status,
o child PCE configuration and information, o child PCE configuration and information,
o notifications to indicate session changes between parent PCEs and o notifications to indicate session changes between parent PCEs and
child PCEs, and child PCEs, and
o notification of parent PCE TED updates and changes. o notification of parent PCE TED updates and changes.
6.3. Liveness Detection and Monitoring 6.3. Liveness Detection and Monitoring
The hierarchical procedure requires interaction with multiple PCEs. The hierarchical procedure requires interaction with multiple PCEs.
Once a child PCE requests an end-to-end path, a sequence of events Once a child PCE requests an end-to-end path, a sequence of events
occurs that requires interaction between the parent PCE and each occurs that requires interaction between the parent PCE and each
skipping to change at page 16, line 28 skipping to change at page 18, line 17
o notification of parent PCE TED updates and changes. o notification of parent PCE TED updates and changes.
6.3. Liveness Detection and Monitoring 6.3. Liveness Detection and Monitoring
The hierarchical procedure requires interaction with multiple PCEs. The hierarchical procedure requires interaction with multiple PCEs.
Once a child PCE requests an end-to-end path, a sequence of events Once a child PCE requests an end-to-end path, a sequence of events
occurs that requires interaction between the parent PCE and each occurs that requires interaction between the parent PCE and each
child PCE. If a child PCE is not operational, and an alternate child PCE. If a child PCE is not operational, and an alternate
transit domain is not available, then a failure must be reported. transit domain is not available, then a failure must be reported.
6.4. Verifying Correct Operation 6.4. Verify Correct Operations
Verifying the correct operation of a parent PCE can be performed by Verifying the correct operation of a parent PCE can be performed by
monitoring a set of parameters. The parent PCE implementation should monitoring a set of parameters. The parent PCE implementation should
provide the following parameters monitored by the parent PCE: provide the following parameters monitored by the parent PCE:
o number of child PCE requests, o number of child PCE requests,
o number of successful hierarchical PCE procedures completions on a o number of successful hierarchical PCE procedures completions on a
per-PCE-peer basis, per-PCE-peer basis,
o number of hierarchical PCE procedure completion failures on a per- o number of hierarchical PCE procedure completion failures on a per-
PCE-peer basis, and PCE-peer basis, and
o number of hierarchical PCE procedure requests from unauthorized o number of hierarchical PCE procedure requests from unauthorized
child PCEs. child PCEs.
6.5. Impact on Network Operation 6.5. Requirements On Other Protocols
Mechanisms defined in this document do not imply any new requirements
on other protocols.
6.6. Impact On Network Operations
The hierarchical PCE procedure is a multiple-PCE path computation The hierarchical PCE procedure is a multiple-PCE path computation
scheme. Subsequent requests to and from the child and parent PCEs do scheme. Subsequent requests to and from the child and parent PCEs do
not differ from other path computation requests and should not have not differ from other path computation requests and should not have
any significant impact on network operations. any significant impact on network operations.
7. IANA Considerations 7. IANA Considerations
7.1. PCEP TLV Type Indicators
7.1. PCEP TLV
IANA Manages the PCEP TLV code point registry (see [RFC5440]). This IANA Manages the PCEP TLV code point registry (see [RFC5440]). This
is maintained as the "PCEP TLV Type Indicators" sub-registry of the is maintained as the "PCEP TLV Type Indicators" sub-registry of the
"Path Computation Element Protocol (PCEP) Numbers" registry. "Path Computation Element Protocol (PCEP) Numbers" registry.
This document defines three new PCEP TLVs. IANA is requested to make This document defines three new PCEP TLVs. IANA is requested to make
the following allocation: the following allocation:
Type TLV name References Type TLV name References
----------------------------------------------- -----------------------------------------------
TBD1 H-PCE-CAPABILITY TLV This I-D TBD1 H-PCE-CAPABILITY TLV This I-D
TBD2 Domain-ID TLV This I-D TBD2 Domain-ID TLV This I-D
TBD3 H-PCE-FLAG TLV This I-D TBD3 H-PCE-FLAG TLV This I-D
7.2. H-PCE-CAPABILITY TLV Flags 7.2. H-PCE-CAPABILITY TLV Flags
This document requests that a new sub-registry, named " H-PCE- This document requests that a new sub-registry, named " H-PCE-
CAPABILITY TLV Flag Field", is created within the "Path Computation CAPABILITY TLV Flag Field", is created within the "Path Computation
Element Protocol (PCEP) Numbers" registry to manage the Flag field in Element Protocol (PCEP) Numbers" registry to manage the Flag field in
the H-PCE-CAPABILITY TLV of the PCEP OPEN object (class = 1). the H-PCE-CAPABILITY TLV of the PCEP OPEN object (class = 1).
New values are to be assigned by Standards Action [RFC5226]. Each New values are to be assigned by Standards Action [RFC5226]. Each
bit should be tracked with the following qualities: bit should be tracked with the following qualities:
o Bit number (counting from bit 0 as the most significant bit) o Bit number (counting from bit 0 as the most significant bit)
o Capability description o Capability description
o Defining RFC o Defining RFC
The following values are defined in this document: The following values are defined in this document:
Bit Description Reference Bit Description Reference
-------------------------------------------------- --------------------------------------------------
31 R (Parent PCE Request bit) This I.D. 31 R (Parent PCE Request bit) This I.D.
30 I (Parent PCE Indication bit) This I.D. 30 I (Parent PCE Indication bit) This I.D.
7.3. Domain-ID TLV Domain type 7.3. Domain-ID TLV Domain type
This document requests that a new sub-registry, named " Domain-ID TLV This document requests that a new sub-registry, named " Domain-ID TLV
Domain type", is created within the "Path Computation Element Domain type", is created within the "Path Computation Element
Protocol (PCEP) Numbers" registry to manage the Domain-Type Protocol (PCEP) Numbers" registry to manage the Domain-Type field of
field of the Domain-ID TLV. the Domain-ID TLV.
Value Meaning Value Meaning
----------------------------------------------- -----------------------------------------------
1 2-byte AS number 1 2-byte AS number
2 4-byte AS number 2 4-byte AS number
3 4-byte OSPF area ID 3 4-byte OSPF area ID
4 Variable length IS-IS area ID 4 Variable length IS-IS area ID
7.4. H-PCE-FLAG TLV Flags 7.4. H-PCE-FLAG TLV Flags
This document requests that a new sub-registry, named "H-PCE-FLAGS
This document requests that a new sub-registry, named "H-PCE-FLAGS
TLV Flag Field", is created within the "Path Computation Element TLV Flag Field", is created within the "Path Computation Element
Protocol (PCEP) Numbers" registry to manage the Flag field in Protocol (PCEP) Numbers" registry to manage the Flag field in the H-
the H-PCE-FLAGS TLV of the PCEP OPEN object (class = 1). New values PCE-FLAGS TLV of the PCEP OPEN object (class = 1). New values are to
are to be assigned by Standards Action [RFC5226]. Each bit should be be assigned by Standards Action [RFC5226]. Each bit should be
tracked with the following qualities: tracked with the following qualities:
o Bit number (counting from bit 0 as the most significant bit) o Bit number (counting from bit 0 as the most significant bit)
o Capability description o Capability description
o Defining RFC o Defining RFC
The following values are defined in this document: The following values are defined in this document:
Bit Description Reference Bit Description Reference
----------------------------------------------- -----------------------------------------------
31 S (Domain This I.D. 31 S (Domain This I.D.
Sequence bit) Sequence bit)
30 D (Disallow Domain This I.D. 30 D (Disallow Domain This I.D.
Re-entry bit) Re-entry bit)
7.5. OF Codes 7.5. OF Codes
IANA maintains registry of Objective Function (described in IANA maintains registry of Objective Function (described in
[RFC5541]) at the sub-registry "Objective Function". Two new [RFC5541]) at the sub-registry "Objective Function". Two new
Objective Functions have been defined in this document. Objective Functions have been defined in this document.
IANA is requested to make the following allocations: IANA is requested to make the following allocations:
Code Code
Point Name Reference Point Name Reference
------------------------------------------------------ ------------------------------------------------------
TBD4 Minimum number of Transit This I.D. TBD4 Minimum number of Transit This I.D.
Domains (MTD) Domains (MTD)
TBD5 Minimize number of Border This I.D. TBD5 Minimize number of Border This I.D.
Nodes (MBN) Nodes (MBN)
TBD13 Minimize the number of This I.D.
Common Transit Domains.
(MCTD)
7.6. METRIC Types 7.6. METRIC Types
IANA maintains one sub-registry for "METRIC object T field". Two new IANA maintains one sub-registry for "METRIC object T field". Two new
metric types are defined in this document for the METRIC object metric types are defined in this document for the METRIC object
(specified in [RFC5440]). (specified in [RFC5440]).
IANA is requested to make the following allocations: IANA is requested to make the following allocations:
Value Description Reference Value Description Reference
---------------------------------------------------------- ----------------------------------------------------------
TBD6 Domain Count metric This I.D. TBD6 Domain Count metric This I.D.
TBD7 Border Node Count metric This I.D. TBD7 Border Node Count metric This I.D.
7.7. New PCEP Error-Types and Values 7.7. New PCEP Error-Types and Values
IANA maintains a registry of Error-Types and Error-values for use in IANA maintains a registry of Error-Types and Error-values for use in
PCEP messages. This is maintained as the "PCEP-ERROR Object Error PCEP messages. This is maintained as the "PCEP-ERROR Object Error
Types and Values" sub-registry of the "Path Computation Element Types and Values" sub-registry of the "Path Computation Element
Protocol (PCEP) Numbers" registry. Protocol (PCEP) Numbers" registry.
IANA is requested to make the following allocations: IANA is requested to make the following allocations:
Error-Type Meaning and error values Reference Error-Type Meaning and error values Reference
------------------------------------------------------ ------------------------------------------------------
TBD8 H-PCE Error This I.D. TBD8 H-PCE Error This I.D.
Error-value=1 Parent PCE Error-value=1 Parent PCE
Capability not advertised Capability not advertised
Error-value=2 Parent PCE Error-value=2 Parent PCE
Capability not supported Capability not supported
7.8. New NO-PATH-VECTOR TLV Bit Flag 7.8. New NO-PATH-VECTOR TLV Bit Flag
IANA maintains a registry of bit flags carried in the PCEP NO-PATH- IANA maintains a registry of bit flags carried in the PCEP NO-PATH-
VECTOR TLV in the PCEP NO-PATH object as defined in [RFC5440]. IANA VECTOR TLV in the PCEP NO-PATH object as defined in [RFC5440]. IANA
Is requested to assign three new bit flag as follows: Is requested to assign three new bit flag as follows:
Bit Number Name Flag Reference Bit Number Name Flag Reference
------------------------------------------------------ ------------------------------------------------------
TBD9 Destination Domain unknown This I.D. TBD9 Destination Domain unknown This I.D.
TBD10 Unresponsive child PCE(s) This I.D. TBD10 Unresponsive child PCE(s) This I.D.
TBD11 No available resource in This I.D. TBD11 No available resource in This I.D.
one or more domain one or more domain
7.9. SVEC Flag
IANA maintains a registry of bit flags carried in the PCEP SVEC
object as defined in [RFC5440]. IANA Is requested to assign one new
bit flag as follows:
Bit Number Name Flag Reference
------------------------------------------------------
TBD13 Domain Diverse This I.D.
8. Security Considerations 8. Security Considerations
The hierarchical PCE procedure relies on PCEP and inherits the The hierarchical PCE procedure relies on PCEP and inherits the
security requirements defined in [RFC5440]. As PCEP operates security requirements defined in [RFC5440]. As PCEP operates over
over TCP, it may also make use of TCP security mechanisms, such as TCP, it may also make use of TCP security mechanisms, such as TCP-AO
TCP-AO or [I-D.ietf-pce-pceps]. or [RFC8253].
H-PCE operation also relies on information used to build the TED. H-PCE operation also relies on information used to build the TED.
Attacks on a parent or child PCE may be achieved by falsifying Attacks on a parent or child PCE may be achieved by falsifying or
or impeding this flow of information. If the child PCE listens to impeding this flow of information. If the child PCE listens to the
the IGP or BGP-LS for populating the TED, then normal IGP or BGP-LS IGP or BGP-LS for populating the TED, then normal IGP or BGP-LS
security measures may be applied, and it should be noted that an IGP security measures may be applied, and it should be noted that an IGP
routing system is generally assumed to be a trusted domain such that routing system is generally assumed to be a trusted domain such that
router subversion is not a risk. The parent PCE TED is constructed as router subversion is not a risk. The parent PCE TED is constructed
described in this document and may involve: as described in this document and may involve:
o multiple parent-child relationships using PCEP o multiple parent-child relationships using PCEP
o the parent PCE listening to child domain IGPs (with the same o the parent PCE listening to child domain IGPs (with the same
security features as a child PCE listening to its IGP) security features as a child PCE listening to its IGP)
o an external mechanism (such as [RFC7752]), which will need to be o an external mechanism (such as [RFC7752]), which will need to be
authorized and secured. authorized and secured.
Any multi-domain operation necessarily involves the exchange of Any multi-domain operation necessarily involves the exchange of
information across domain boundaries. This is bound to represent a information across domain boundaries. This is bound to represent a
significant security and confidentiality risk especially when the significant security and confidentiality risk especially when the
child domains are controlled by different commercial concerns. PCEP child domains are controlled by different commercial concerns. PCEP
allows individual PCEs to maintain confidentiality of their domain allows individual PCEs to maintain confidentiality of their domain
path information using path-keys [RFC5520], and the H-PCE path information using path-keys [RFC5520], and the H-PCE
architecture is specifically designed to enable as much isolation of architecture is specifically designed to enable as much isolation of
domain topology and capabilities information as is possible. domain topology and capabilities information as is possible.
For further considerations of the security issues related to inter-AS For further considerations of the security issues related to inter-AS
path computation, see [RFC5376]. path computation, see [RFC5376].
9. Implementation Status 9. Implementation Status
The H-PCE architecture and protocol procedures describe in this I-D The H-PCE architecture and protocol procedures describe in this I-D
were implemented and tested for a variety of optical research were implemented and tested for a variety of optical research
applications. applications.
9.1 Inter-layer traffic engineering with H-PCE 9.1. Inter-layer traffic engineering with H-PCE
This work was led by: This work was led by:
o Ramon Casellas <ramon.casellas@cttc.es> o Ramon Casellas [ramon.casellas@cttc.es]
o Centre Tecnologic de Telecomunicacions de Catalunya (CTTC) o Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)
The H-PCE instances (parent and child) were multi-threaded The H-PCE instances (parent and child) were multi-threaded
asynchronous processes. Implemented in C++11, using C++ Boost asynchronous processes. Implemented in C++11, using C++ Boost
Libraries. The targeted system used to deploy and run H-PCE Libraries. The targeted system used to deploy and run H-PCE
applications was a POSIX system (Debian GNU/Linux operating applications was a POSIX system (Debian GNU/Linux operating system).
system).
Some parts of the software may require a Linux Kernel, the Some parts of the software may require a Linux Kernel, the
availability of a Routing Controller running collocated in the same availability of a Routing Controller running collocated in the same
host and the usage of libnetfilter / libipq and GNU/Linux host and the usage of libnetfilter / libipq and GNU/Linux firewalling
firewalling capabilities. Most of the functionality, including capabilities. Most of the functionality, including algorithms is
algorithms is done by means of plugins (e.g., as shared libraries done by means of plugins (e.g., as shared libraries or .so files in
or .so files in Unix systems). Unix systems).
The CTTC PCE supports the H-PCE architecture, but also supports The CTTC PCE supports the H-PCE architecture, but also supports
stateful PCE with active capabilities, as an OpenFlow controller, stateful PCE with active capabilities, as an OpenFlow controller, and
and has dedicated plugins to support monitoring, BRPC, P2MP, path has dedicated plugins to support monitoring, BRPC, P2MP, path keys,
keys, back end PCEs. Management of the H-PCE entities was supported back end PCEs. Management of the H-PCE entities was supported via
via HTTP and CLI via Telnet. HTTP and CLI via Telnet.
Further details of the H-PCE prototyping and experimentation can be Further details of the H-PCE prototyping and experimentation can be
found in the following scientific papers: found in the following scientific papers:
R. Casellas, R. Martinez, R. Munoz, L. Liu, T. Tsuritani, I. R. Casellas, R. Martinez, R. Munoz, L. Liu, T. Tsuritani, I.
Morita, "Inter-layer traffic engineering with hierarchical-PCE in
Morita, "Inter-layer traffic engineering with hierarchical-PCE in MPLS-TP over wavelength switched optical networks" , Optics
MPLS-TP over wavelength switched optical networks" , Optics Express, Vol. 20, No. 28, December 2012.
Express, Vol. 20, No. 28, December 2012.
R. Casellas, R. Martinez, R. Munoz, L. Liu, T. Tsuritani, I. Morita, R. Casellas, R. Martinez, R. Munoz, L. Liu, T. Tsuritani, I.
M. Msurusawa, "Dynamic virtual link mesh topology aggregation in Morita, M. Msurusawa, "Dynamic virtual link mesh topology
multi-domain translucent WSON with hierarchical-PCE", Optics Express aggregation in multi-domain translucent WSON with hierarchical-
Journal, Vol. 19, No. 26, December 2011. PCE", Optics Express Journal, Vol. 19, No. 26, December 2011.
R. Casellas, R. Munoz, R. Martinez, R. Vilalta, L. Liu, T. Tsuritani, R. Casellas, R. Munoz, R. Martinez, R. Vilalta, L. Liu, T.
I. Morita, V. Lopez, O. Gonzalez de Dios, J. P. Fernandez-Palacios, Tsuritani, I. Morita, V. Lopez, O. Gonzalez de Dios, J. P.
"SDN based Provisioning Orchestration of OpenFlow/GMPLS Flexi-grid Fernandez-Palacios, "SDN based Provisioning Orchestration of
Networks with a Stateful Hierarchical PCE", in Proceedings of Optical OpenFlow/GMPLS Flexi-grid Networks with a Stateful Hierarchical
Fiber Communication Conference and Exposition (OFC), 9-13 March, PCE", in Proceedings of Optical Fiber Communication Conference and
2014, San Francisco (EEUU). Extended Version to appear in Journal Exposition (OFC), 9-13 March, 2014, San Francisco (EEUU).
Of Optical Communications and Networking January 2015 Extended Version to appear in Journal Of Optical Communications
and Networking January 2015
F. Paolucci, O. Gonzalez de Dios, R. Casellas, S. Duhovnikov, P. F. Paolucci, O. Gonzalez de Dios, R. Casellas, S. Duhovnikov,
Castoldi, R. Munoz, R. Martinez, "Experimenting Hierarchical PCE P. Castoldi, R. Munoz, R. Martinez, "Experimenting Hierarchical
Architecture in a Distributed Multi-Platform Control Plane Testbed" , PCE Architecture in a Distributed Multi-Platform Control Plane
in Proceedings of Optical Fiber Communication Conference and Testbed" , in Proceedings of Optical Fiber Communication
Exposition (OFC) and The National Fiber Optic Engineers Conference Conference and Exposition (OFC) and The National Fiber Optic
(NFOEC), 4-8 March, 2012, Los Angeles, California (USA). Engineers Conference (NFOEC), 4-8 March, 2012, Los Angeles,
California (USA).
R. Casellas, R. Martinez, R. Munoz, L. Liu, T. Tsuritani, I. Morita, R. Casellas, R. Martinez, R. Munoz, L. Liu, T. Tsuritani, I.
M. Tsurusawa, "Dynamic Virtual Link Mesh Topology Aggregation in Morita, M. Tsurusawa, "Dynamic Virtual Link Mesh Topology
Multi-Domain Translucent WSON with Hierarchical-PCE", in Aggregation in Multi-Domain Translucent WSON with Hierarchical-
Proceedings of 37th European Conference and Exhibition on Optical PCE", in Proceedings of 37th European Conference and Exhibition on
Communication (ECOC 2011), 18-22 September 2011, Geneve ( Optical Communication (ECOC 2011), 18-22 September 2011, Geneve (
Switzerland). Switzerland).
R. Casellas, R. Munoz, R. Martinez, "Lab Trial of Multi-Domain Path R. Casellas, R. Munoz, R. Martinez, "Lab Trial of Multi-Domain
Computation in GMPLS Controlled WSON Using a Hierarchical PCE", in Path Computation in GMPLS Controlled WSON Using a Hierarchical
Proceedings of OFC/NFOEC Conference (OFC2011), 10 March 2011, Los PCE", in Proceedings of OFC/NFOEC Conference (OFC2011), 10 March
Angeles (USA). 2011, Los Angeles (USA).
9.2 Telefonica Netphony (Open Source PCE) 9.2. Telefonica Netphony (Open Source PCE)
The Telefonica Netphony PCE is an open source Java-based The Telefonica Netphony PCE is an open source Java-based
implementation of a Path Computation Element, with several flavours, implementation of a Path Computation Element, with several flavours,
and a Path Computation Client. The PCE follows a modular architecture and a Path Computation Client. The PCE follows a modular
and allows to add customized algorithms. The PCE has also stateful architecture and allows to add customized algorithms. The PCE has
and remote initiation capabilities. In current version, three also stateful and remote initiation capabilities. In current
components can be built, a domain PCE (aka child PCE), a parent PCE version, three components can be built, a domain PCE (aka child PCE),
(ready for the H-PCE architecture) and a PCC (path computation a parent PCE (ready for the H-PCE architecture) and a PCC (path
client). computation client).
This work was led by: This work was led by:
o Oscar Gonzalez de Dios <oscar.gonzalezdedios@telefonica.com> o Oscar Gonzalez de Dios [oscar.gonzalezdedios@telefonica.com]
o Victor Lopez Alvarez <victor.lopezalvarez@telefonica.com>
o Victor Lopez Alvarez [victor.lopezalvarez@telefonica.com]
o Telefonica I+D, Madrid, Spain o Telefonica I+D, Madrid, Spain
The PCE code is publicly available in a GitHub repository: The PCE code is publicly available in a GitHub repository:
* https://github.com/telefonicaid/netphony-pce
o https://github.com/telefonicaid/netphony-pce
The PCEP protocol encodings are located in the following repository: The PCEP protocol encodings are located in the following repository:
* https://github.com/telefonicaid/netphony-network protocols
o https://github.com/telefonicaid/netphony-network protocols
The traffic engineering database and a BGP-LS speaker to fill the The traffic engineering database and a BGP-LS speaker to fill the
database is located in: database is located in:
* https://github.com/telefonicaid/netphony-topology
The parent and child PCE are multi-threaded java applications. The o https://github.com/telefonicaid/netphony-topology
The parent and child PCE are multi-threaded java applications. The
path computation uses the jgrapht free Java class library (0.9.1) path computation uses the jgrapht free Java class library (0.9.1)
that provides mathematical graph-theory objects and algorithms. that provides mathematical graph-theory objects and algorithms.
Current version of netphony PCE runs on java 1.7 and 1.8, and has Current version of netphony PCE runs on java 1.7 and 1.8, and has
been tested in GNU/Linux, Mac OS-X and Windows environments. The been tested in GNU/Linux, Mac OS-X and Windows environments. The
management of the parent and domain PCEs is supported though CLI via management of the parent and domain PCEs is supported though CLI via
Telnet, and configured via XML files . Telnet, and configured via XML files.
Further details of the netphony H-PCE prototyping and experimentation Further details of the netphony H-PCE prototyping and experimentation
can be found in the following research papers: can be found in the following research papers:
O. Gonzalez de Dios, R. Casellas, F. Paolucci, A. Napoli, L. Gifre, o O. Gonzalez de Dios, R. Casellas, F. Paolucci, A. Napoli, L.
A. Dupas, E, Hugues-Salas, R. Morro, S. Belotti, G. Meloni, T. Gifre, A. Dupas, E, Hugues-Salas, R. Morro, S. Belotti, G.
Rahman, V.P Lopez, R. Martinez, F. Fresi, M. Bohn, S. Yan, L. Meloni, T. Rahman, V.P Lopez, R. Martinez, F. Fresi, M. Bohn,
Velasco, . Layec and J. P. Fernandez-Palacios: Experimental S. Yan, L. Velasco, . Layec and J. P. Fernandez-Palacios:
Demonstration of Multivendor and Multidomain EON With Data and Experimental Demonstration of Multivendor and Multidomain EON With
Control Interoperability Over a Pan-European Test Bed, in Journal of Data and Control Interoperability Over a Pan-European Test Bed, in
Lightwave Technology, Dec. 2016, Vol. 34, Issue 7, pp. 1610-1617. Journal of Lightwave Technology, Dec. 2016, Vol. 34, Issue 7, pp.
1610-1617.
O. Gonzalez de Dios, R. Casellas, R. Morro, F. Paolucci, V. Lopez, o O. Gonzalez de Dios, R. Casellas, R. Morro, F. Paolucci, V.
R. Martinez, R. Munoz, R. Villalta, P. Castoldi: "Multi-partner Lopez, R. Martinez, R. Munoz, R. Villalta, P. Castoldi:
Demonstration of BGP-LS enabled multi-domain EON, in Journal of "Multi-partner Demonstration of BGP-LS enabled multi-domain EON,
Optical Communications and Networking, Dec. 2015, Vol. 7, Issue 12, in Journal of Optical Communications and Networking, Dec. 2015,
pp. B153-B162. Vol. 7, Issue 12, pp. B153-B162.
F. Paolucci, O. Gonzalez de Dios, R. Casellas, S. Duhovnikov, P. o F. Paolucci, O. Gonzalez de Dios, R. Casellas, S. Duhovnikov,
Castoldi, R. Munoz, R. Martinez, "Experimenting Hierarchical PCE P. Castoldi, R. Munoz, R. Martinez, "Experimenting Hierarchical
Architecture in a Distributed Multi-Platform Control Plane Testbed" , PCE Architecture in a Distributed Multi-Platform Control Plane
in Proceedings of Optical Fiber Communication Conference and Testbed" , in Proceedings of Optical Fiber Communication
Exposition (OFC) and The National Fiber Optic Engineers Conference Conference and Exposition (OFC) and The National Fiber Optic
(NFOEC), 4-8 March, 2012, Los Angeles, California (USA). Engineers Conference (NFOEC), 4-8 March, 2012, Los Angeles,
California (USA).
9.3 Implementation 3: H-PCE Proof of Concept developed by Huawei 9.3. Implementation 3: H-PCE Proof of Concept developed by Huawei
Huawei developed this H-PCE on the Huawei Versatile Routing Platform Huawei developed this H-PCE on the Huawei Versatile Routing Platform
(VRP) to experiment with the hierarchy of PCE. Both end to end path (VRP) to experiment with the hierarchy of PCE. Both end to end path
computation as well as computation for domain-sequence are supported. computation as well as computation for domain-sequence are supported.
This work was led by: This work was led by:
o Udayasree Pallee <udayasree.palle@huawei.com> o Udayasree Pallee [udayasreereddy@gmail.com]
o Dhruv Dhody <dhruv.ietf@gmail.com>
o Huawei Technologies, Bangalore, India
Further work on stateful H-PCE is being carried out on ONOS. o Dhruv Dhody [dhruv.ietf@gmail.com]
10. Contributing Authors o Huawei Technologies, Bangalore, India
Xian Zhang Further work on stateful H-PCE [I-D.ietf-pce-stateful-hpce] is being
Huawei carried out on ONOS.
zhang.xian@huawei.com
Dhruv Dhody 10. Contributing Authors
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560066
India
EMail: dhruv.ietf@gmail.com Xian Zhang
Huawei
EMail: zhang.xian@huawei.com
11. Acknowledgments Dhruv Dhody
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560066
India
12. References EMail: dhruv.ietf@gmail.com
12.1 Normative References 11. References
11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
[RFC5152] Vasseur, JP., Ayyangar, A., and R. Zhang, "A Per-Domain <https://www.rfc-editor.org/info/rfc2119>.
Path Computation Method for Establishing Inter-Domain
Traffic Engineering (TE) Label Switched Paths (LSPs)",
RFC 5152, February 2008.
[RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element [RFC5152] Vasseur, JP., Ed., Ayyangar, A., Ed., and R. Zhang, "A
(PCE) Communication Protocol (PCEP)", RFC 5440, Per-Domain Path Computation Method for Establishing Inter-
March 2009. Domain Traffic Engineering (TE) Label Switched Paths
(LSPs)", RFC 5152, DOI 10.17487/RFC5152, February 2008,
<https://www.rfc-editor.org/info/rfc5152>.
[RFC5441] Vasseur, JP., Zhang, R., Bitar, N., and JL. Le Roux, "A [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Backward-Recursive PCE-Based Computation (BRPC) Procedure Element (PCE) Communication Protocol (PCEP)", RFC 5440,
to Compute Shortest Constrained Inter-Domain Traffic DOI 10.17487/RFC5440, March 2009,
Engineering Label Switched Paths", RFC 5441, April 2009. <https://www.rfc-editor.org/info/rfc5440>.
[RFC5541] Le Roux, JL., Vasseur, JP., and Y. Lee, "Encoding of [RFC5541] Le Roux, JL., Vasseur, JP., and Y. Lee, "Encoding of
Objective Functions in the Path Computation Element Objective Functions in the Path Computation Element
Communication Protocol (PCEP)", RFC 5541, June 2009. Communication Protocol (PCEP)", RFC 5541,
DOI 10.17487/RFC5541, June 2009,
<https://www.rfc-editor.org/info/rfc5541>.
12.2 Informative References [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>.
11.2. Informative References
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655, August 2006. Element (PCE)-Based Architecture", RFC 4655,
DOI 10.17487/RFC4655, August 2006,
<https://www.rfc-editor.org/info/rfc4655>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, IANA Considerations Section in RFCs", RFC 5226,
DOI 10.17487/RFC5226, May 2008, DOI 10.17487/RFC5226, May 2008,
<https://www.rfc-editor.org/info/rfc5226>.
[RFC5376] Bitar, N., Zhang, R., and K. Kumaki, "Inter-AS [RFC5376] Bitar, N., Zhang, R., and K. Kumaki, "Inter-AS
Requirements for the Path Computation Element Requirements for the Path Computation Element
Communication Protocol (PCECP)", RFC 5376, November Communication Protocol (PCECP)", RFC 5376,
2008. DOI 10.17487/RFC5376, November 2008,
<https://www.rfc-editor.org/info/rfc5376>.
[RFC5394] Bryskin, I., Papadimitriou, D., Berger, L., and J. Ash, [RFC5394] Bryskin, I., Papadimitriou, D., Berger, L., and J. Ash,
"Policy-Enabled Path Computation Framework", RFC 5394, "Policy-Enabled Path Computation Framework", RFC 5394,
December 2008. DOI 10.17487/RFC5394, December 2008,
<https://www.rfc-editor.org/info/rfc5394>.
[RFC5520] Bradford, R., Ed., Vasseur, JP., and A. Farrel, [RFC5520] Bradford, R., Ed., Vasseur, JP., and A. Farrel,
"Preserving Topology Confidentiality in Inter-Domain "Preserving Topology Confidentiality in Inter-Domain Path
Path Computation Using a Path-Key-Based Mechanism", Computation Using a Path-Key-Based Mechanism", RFC 5520,
RFC 5520, April 2009. DOI 10.17487/RFC5520, April 2009,
<https://www.rfc-editor.org/info/rfc5520>.
[RFC6805] King, D. and A. Farrel, "The Application of the Path [RFC5441] Vasseur, JP., Ed., Zhang, R., Bitar, N., and JL. Le Roux,
Computation Element Architecture to the Determination of a "A Backward-Recursive PCE-Based Computation (BRPC)
Sequence of Domains in MPLS and GMPLS", RFC 6805, Procedure to Compute Shortest Constrained Inter-Domain
November 2012. Traffic Engineering Label Switched Paths", RFC 5441,
DOI 10.17487/RFC5441, April 2009,
<https://www.rfc-editor.org/info/rfc5441>.
[RFC7420] Koushik, A., Stephan, E., Zhao, Q., King, D., Hardwick, [RFC6805] King, D., Ed. and A. Farrel, Ed., "The Application of the
J., "Path Computation Element Communication Protocol Path Computation Element Architecture to the Determination
(PCEP) Management Information Base (MIB) Module", RFC of a Sequence of Domains in MPLS and GMPLS", RFC 6805,
7420, December 2014. DOI 10.17487/RFC6805, November 2012,
<https://www.rfc-editor.org/info/rfc6805>.
[RFC7752] Gredler, H., Medved, J., Previdi, S., Farrel, A., and [RFC7470] Zhang, F. and A. Farrel, "Conveying Vendor-Specific
S. Ray, "North-Bound Distribution of Link-State and TE Constraints in the Path Computation Element Communication
Information using BGP", Work in Progress, RFC 7752, Protocol", RFC 7470, DOI 10.17487/RFC7470, March 2015,
March, 2016. <https://www.rfc-editor.org/info/rfc7470>.
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016,
<https://www.rfc-editor.org/info/rfc7752>.
[RFC7897] Dhody, D., Palle, U., and R. Casellas, "Domain Subobjects [RFC7897] Dhody, D., Palle, U., and R. Casellas, "Domain Subobjects
for the Path Computation Element Communication Protocol for the Path Computation Element Communication Protocol
(PCEP)", RFC 7897, DOI 10.17487/RFC7897, June 2016. (PCEP)", RFC 7897, DOI 10.17487/RFC7897, June 2016,
<https://www.rfc-editor.org/info/rfc7897>.
[I-D.ietf-pce-pceps] [RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody,
Lopez, D., Dios, O., Wu, W., and D. Dhody, "Secure "PCEPS: Usage of TLS to Provide a Secure Transport for the
Transport for PCEP", draft-ietf-pce-pceps (work in Path Computation Element Communication Protocol (PCEP)",
progress), March 2016. RFC 8253, DOI 10.17487/RFC8253, October 2017,
<https://www.rfc-editor.org/info/rfc8253>.
[I-D.pkd-pce-pcep-yang] [I-D.ietf-pce-pcep-yang]
Dhody, D., Hardwick, J., Beeram, V., and J. Tantsura, "A Dhody, D., Hardwick, J., Beeram, V., and J. Tantsura, "A
YANG Data Model for Path Computation Element YANG Data Model for Path Computation Element
Communications Protocol (PCEP)", draft-pkd-pce-pcep- Communications Protocol (PCEP)", draft-ietf-pce-pcep-
yang (work in progress), January 2016. yang-07 (work in progress), March 2018.
[I-D.ietf-pce-stateful-hpce]
Dhody, D., Lee, Y., Ceccarelli, D., Shin, J., King, D.,
and O. Dios, "Hierarchical Stateful Path Computation
Element (PCE).", draft-ietf-pce-stateful-hpce-04 (work in
progress), March 2018.
Authors' Addresses Authors' Addresses
Fatai Zhang Fatai Zhang
Huawei Huawei
Huawei Base, Bantian, Longgang District Huawei Base, Bantian, Longgang District
Shenzhen, 518129 Shenzhen 518129
China China
Phone: +86-755-28972912 EMail: zhangfatai@huawei.com
Email: zhangfatai@huawei.com
Quintin Zhao Quintin Zhao
Huawei Huawei
125 Nagog Technology Park 125 Nagog Technology Park
Acton, MA 01719 Acton, MA 01719
US USA
Phone: EMail: quintin.zhao@huawei.com
Email: qzhao@huawei.com
Oscar Gonzalez de Dios Oscar Gonzalez de Dios
Telefonica I+D Telefonica I+D
Don Ramon de la Cruz 82-84 Don Ramon de la Cruz 82-84
Madrid, 28045 Madrid 28045
Spain Spain
Phone: +34913128832 EMail: ogondio@tid.es
Email: ogondio@tid.es
Ramon Casellas Ramon Casellas
CTTC CTTC
Av. Carl Friedrich Gauss n.7 Av. Carl Friedrich Gauss n.7
Castelldefels, Barcelona Barcelona, Castelldefels
Spain Spain
Phone: +34 93 645 29 00 EMail: ramon.casellas@cttc.es
Email: ramon.casellas@cttc.es
Daniel King Daniel King
Old Dog Consulting Old Dog Consulting
UK UK
Phone: EMail: daniel@olddog.co.uk
Email: daniel@olddog.co.uk
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