Network Working Group E. Oki
Internet-Draft UEC Tokyo
Intended status: Standards Track Tomonori Takeda
NTT
J-L Le Roux
France Telecom
A. Farrel
Juniper Networks
Fatai Zhang
Huawei
Expires: July 24, 2014 January 24, 2014
Extensions to the Path Computation Element communication Protocol
(PCEP) for Inter-Layer MPLS and GMPLS Traffic Engineering
draft-ietf-pce-inter-layer-ext-08.txt
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This Internet-Draft will expire on July 24, 2014.
Abstract
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The Path Computation Element (PCE) provides path computation
functions in support of traffic engineering in Multiprotocol Label
Switching (MPLS) and Generalized MPLS (GMPLS) networks.
MPLS and GMPLS networks may be constructed from layered service
networks. It is advantageous for overall network efficiency to
provide end-to-end traffic engineering across multiple network layers
through a process called inter-layer traffic engineering. PCE is a
candidate solution for such requirements.
The PCE communication Protocol (PCEP) is designed as a communication
protocol between Path Computation Clients (PCCs) and PCEs. This
document presents PCEP extensions for inter-layer traffic engineering.
Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC-2119 [RFC2119].
Table of Contents
1. Introduction ................................................. 3
2. Overview of PCE-Based Inter-Layer Path Computation ........... 3
3. Protocol Extensions .......................................... 4
3.1. INTER-LAYER Object....................................... 4
3.2. SWITCH-LAYER Object ..................................... 7
3.3. REQ-ADAP-CAP Object ..................................... 8
3.4. New Metric Types......................................... 9
3.5. ERO sub-object ......................................... 10
4. Procedures .................................................. 10
4.1. Path Computation Request ............................... 10
4.2. Path Computation Reply ................................. 11
5. Updated Format of PCEP Messages ............................. 12
6. Manageability Considerations ................................ 13
7. IANA Considerations ......................................... 13
7.1. New PCEP Objects........................................ 13
7.2. New Registry for INTER-LAYER Object Flags .............. 14
7.3. METRIC Type ............................................ 15
8. Security Considerations ..................................... 15
9. Acknowledgments ............................................. 15
10. References ................................................. 15
10.1. Normative References .................................. 15
10.2. Informative References ................................ 16
11. Authors' Addresses ......................................... 16
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1. Introduction
The Path Computation Element (PCE) defined in [RFC4655] is an entity
that is capable of computing a network path or route based on a
network graph, and applying computational constraints. A Path
Computation Client (PCC) may make requests to a PCE for paths to be
computed.
A network may comprise multiple layers. These layers may represent
separations of technologies (e.g., packet switch capable (PSC), time
division multiplex (TDM), lambda switch capable (LSC)) [RFC3945],
separation of data plane switching granularity levels (e.g., PSC-1
and PSC-2, or VC4 and VC12) [RFC5212], or a distinction between
client and server networking roles (e.g., commercial or
administrative separation of client and server networks). In this
multi-layer network, Label Switched Paths (LSPs) in lower layers are
used to carry higher-layer LSPs. The network topology formed by
lower-layer LSPs and advertised as traffic engineering links (TE
links) in the higher layer is called a Virtual Network Topology (VNT)
[RFC5212].
It is important to optimize network resource utilization globally,
i.e., taking into account all layers, rather than optimizing resource
utilization at each layer independently. This allows better network
efficiency to be achieved. This is what we call inter-layer traffic
engineering. This includes mechanisms allowing the computation of
end-to-end paths across layers (known as inter-layer path
computation), and mechanisms for control and management of the VNT by
setting up and releasing LSPs in the lower layers [RFC5212].
PCE can provide a suitable mechanism for resolving inter-layer path
computation issues. The framework for applying the PCE-based path
computation architecture to inter-layer traffic engineering is
described in [RFC5623].
The PCE communication protocol (PCEP) is designed as a communication
protocol between PCCs and PCEs and is defined in [RFC5440]. A set of
requirements for PCEP extensions to support inter-layer traffic
engineering is described in [RFC6457].
This document presents PCEP extensions for inter-layer traffic
engineering that satisfy the requirements described in [RFC6457].
2. Overview of PCE-Based Inter-Layer Path Computation
[RFC4206] defines a way to signal a higher-layer LSP which has an
explicit route that includes hops traversed by LSPs in lower layers.
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The computation of end-to-end paths across layers is called Inter-
Layer Path Computation.
A Label Switching Router (LSR) in the higher-layer might not have
information on the lower-layer topology, particularly in an overlay
or augmented model [RFC3945], and hence may not be able to compute an
end-to-end path across layers.
PCE-based inter-layer path computation consists of using one or more
PCEs to compute an end-to-end path across layers. This could be
achieved by relying on a single PCE that has topology information
about multiple layers and can directly compute an end-to-end path
across layers considering the topology of all of the layers.
Alternatively, the inter-layer path computation could be performed
using multiple cooperating PCEs where each PCE has information about
the topology of one or more layers (but not all layers) and where the
PCEs collaborate to compute an end-to-end path.
As described in [RFC5339], a hybrid nodes may advertise a single TE
link with multiple switching capabilities. Those TE links exist at
the layer/region boarder normally. In this case, PCE needs to be
capable of specifying the server layer path information when the
server layer path information is required to be returned to the PCC.
[RFC5623] describes models for inter-layer path computation in more
detail.
3. Protocol Extensions
This section describes PCEP extensions for inter-layer path
computation. Three new objects are defined: the INTER-LAYER object,
the SWITCH-LAYER object, the REQ-ADAP-CAP object and SERVER-
INDICATION. Also, two new metric types are defined.
3.1. INTER-LAYER Object
The INTER-LAYER object is optional and can be used in PCReq and PCRep
messages.
In a PCReq message, the INTER-LAYER object indicates whether inter-
layer path computation is allowed, the type of path to be computed,
and whether triggered signaling (hierarchical LSPs per [RFC4206] or
stitched LSPs per [RFC5150] depending on physical network
technologies) is allowed. When the INTER-LAYER object is absent from
a PCReq message, the receiving PCE MUST process as though inter-layer
path computation had been explicitly disallowed (I-bit set to zero -
see below).
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In a PCRep message, the INTER-LAYER object indicates whether inter-
layer path computation has been performed, the type of path that has
been computed, and whether triggered signaling is used.
When a PCReq message includes more than one request, an INTER-LAYER
object is used per request. When a PCRep message includes more than
one path per request that is responded to, an INTER-LAYER object is
used per path.
INTER-LAYER Object-Class is to be assigned by IANA (recommended
value=18)
INTER-LAYER Object-Type is to be assigned by IANA (recommended
value=1)
The format of the INTER-LAYER object 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |T|M|I|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
I flag (1 bit): The I flag is used by a PCC in a PCReq message to
indicate to a PCE whether an inter-layer path is allowed. When the I
flag is set (one), the PCE MAY perform inter-layer path computation
and return an inter-layer path. When the flag is clear (zero), the
path that is returned MUST NOT be an inter-layer path.
The I flag is used by a PCE in a PCRep message to indicate to a PCC
whether the path returned is an inter-layer path. When the I flag is
set (one), the path is an inter-layer path. When it is clear (zero),
the path is contained within a single layer either because inter-
layer path computation was not performed or because a mono-layer path
(without any virtual TE link and without any loose hop that spans the
lower-layer network) was found notwithstanding the use of inter-layer
path computation.
M flag (1 bit): The M flag is used by a PCC in a PCReq message to
indicate to a PCE whether mono-layer path or multi-layer path is
requested. When the M flag is set (one), multi-layer path is
requested. When it is clear (zero), mono-layer path is requested.
The M flag is used by a PCE in a PCRep message to indicate to a PCC
whether mono-layer path or multi-layer path is returned. When M flag
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is set (one), multi-layer path is returned. When M flag is set (zero),
mono-layer path is returned.
If the I flag is clear (zero), the M flag has no meaning and MUST be
ignored.
[RFC6457] describes two sub-options for mono-layer path.
- A mono-layer path that is specified by strict hops. The path may
include virtual TE links.
- A mono-layer path that includes loose hops that span the lower-
layer network.
The choice of this sub-option can be specified by the use of O flag
in the RP object specified in [RFC5440].
T flag (1 bit): The T flag is used by a PCC in a PCReq message to
indicate to a PCE whether triggered signaling is allowed. When the T
flag is set (one), triggered signaling is allowed. When it is clear
(zero), triggered signaling is not allowed.
The T flag is used by a PCE in a PCRep message to indicate to a PCC
whether triggered signaling is required to support the returned path.
When the T flag is set (one), triggered signaling is required. When
it is clear (zero), triggered signaling is not required.
Note that triggered signaling is used to support hierarchical
[RFC4206] or stitched [RFC5150] LSPs according to the physical
attributes of the network layers.
If the I flag is clear (zero), the T flag has no meaning and MUST be
ignored.
Note that the I flag and M flag differ in the following ways. - When
the I flag is clear (zero), virtual TE links must not be used in path
computation. In addition, loose hops that span the lower-layer
network must not be specified. Only regular TE links from the same
layer may be used.
- When the I flag is set (one), the M flag is clear (zero), and the T
flag is set (one), virtual TE links are allowed in path computation.
In addition, when the O flag of the RP object is set, loose hops that
span the lower-layer network may be specified. This will initiate
lower-layer LSP setup, thus inter-layer path is setup even though the
path computation result from a PCE to a PCC include hops from the
same layer only.
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- However, when the I flag is set (one), the M flag is clear (zero),
and the T flag is clear (zero), since triggered signaling is not
allowed, virtual TE links must not be used in path computation. In
addition, loose hops that span the lower-layer network must not be
specified. Therefore, this is equivalent to the I flag being clear
(zero).
Reserved bits of the INTER-LAYER object SHOULD be transmitted as zero
and SHOULD be ignored on receipt. A PCE that forwards a path
computation request to other PCEs SHOULD preserve the settings of
reserved bits in the PCReq messages it sends and in the PCRep
messages it forwards to PCCs.
3.2. SWITCH-LAYER Object
The SWITCH-LAYER object is optional on a PCReq message and specifies
switching layers in which a path MUST, or MUST NOT, be established. A
switching layer is expressed as a switching type and encoding type.
When a SWITCH-LAYER object is used on a PCReq it is interpreted in
the context of the INTER-LAYER object on the same message. If no
INTER-LAYER object is present, the PCE MUST process the SWITCH-LAYER
object as though inter-layer path computation had been explicitly
disallowed. In such a case, the SWITCH-LAYER object MUST NOT have
more than one LSP Encoding Type and Switching Type with the I flag
set.
The SWITCH-LAYER object is optional on a PCRep message, where it is
used with the NO-PATH object in the case of unsuccessful path
computation to indicate the set of constraints that could not be
satisfied.
SWITCH-LAYER Object-Class is to be assigned by IANA (recommended
value=19)
SWITCH-LAYER Object-Type is to be assigned by IANA (recommended
value=1)
The format of the SWITCH-LAYER object body is as follows:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSP Enc. Type |Switching Type | Reserved |I|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| . |
// . //
| . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSP Enc. Type |Switching Type | Reserved |I|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Each row indicates a switching type and encoding type that must or
must not be used for specified layer(s) in the computed path.
The format is based on [RFC3471], and has equivalent semantics.
LSP Encoding Type (8 bits): see [RFC3471] for a description of
parameters.
Switching Type (8 bits): see [RFC3471] for a description of
parameters.
I flag (1 bit): the I flag indicates whether a layer with the
specified switching type and encoding type must or must not be used
by the computed path. When the I flag is set (one), the computed path
MUST traverse a layer with the specified switching type and encoding
type. When the I flag is clear (zero), the computed path MUST NOT
enter or traverse any layer with the specified switching type and
encoding type.
When a combination of switching type and encoding type is not
included in SWITCH-LAYER object, the computed path MAY traverse a
layer with that combination of switching type and encoding type.
A PCC may want to specify only a Switching Type and not an LSP
Encoding Type. In this case, the LSP Encoding Type is set to zero.
3.3. REQ-ADAP-CAP Object
The REQ-ADAP-CAP object is optional and is used to specify a
requested adaptation capability for both ends of the lower layer LSP.
The REQ-ADAP-CAP object is used in a PCReq message for inter-PCE
communication, where the PCE that is responsible for computing higher
layer paths acts as a PCC to request a path computation from a PCE
that is responsible for computing lower layer paths.
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The REQ-ADAP-CAP object is used in a PCRep message in case of
unsuccessful path computation (in this case, the PCRep message also
contains a NO-PATH object, and the REQ-ADAP-CAP object is used to
indicate the set of constraints that could not be satisfied).
The REQ-ADAP-CAP object MAY be used in a PCReq message in a mono-
layer network to specify a requested adaptation capability for both
ends of the LSP. In this case, it MAY be carried without INTER-LAYER
Object.
REQ-ADAP-CAP Object-Class is to be assigned by IANA (recommended
value=20)
REQ-ADAP-CAP Object-Type is to be assigned by IANA (recommended
value=1)
The format of the REQ-ADAP-CAP object 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Switching Cap | Encoding | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format is based on [RFC6001] and has equivalent semantics as the
IACD Upper SC and Lower SC.
Switching Capability (8 bits): see [RFC4203] for a description of
parameters.
Encoding (8 bits): see [RFC3471] for a description of parameters.
A PCC may want to specify a Switching Capability, but not an Encoding.
In this case, the Encoding MUST be set zero.
3.4. New Metric Types
Two new metric types are defined for the METRIC object in PCEP.
Type 11 (suggested value, to be assigned by IANA): Number of
adaptations on a path.
Type 12 (suggested value, to be assigned by IANA): Number of layers
to be involved on a path.
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3.5. SERVER-INDICATION object
The SERVER-INDICATION is optional and is used to indicate that path
information included in the ERO is server layer information and
specify the characteristics of the server layer, e.g. the switching
capability and encoding of the server layer path.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Switching Cap | Encoding | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Optional TLVs ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The type of SERVER-INDICATION object is to be assigned by IANA.
Switching Capability (8 bits): see [RFC4203] for a description of
parameters.
Encoding (8 bits): see [RFC3471] for a description of parameters.
Optional TLVs: Optional TLVs may be included within the object to
specify more specific server layer path information (e.g., traffic
parameters).
4. Procedures
4.1. Path Computation Request
A PCC requests or allows inter-layer path computation in a PCReq
message by including the INTER-LAYER object with the I flag set. The
INTER-LAYER object indicates whether inter-layer path computation is
allowed, which path type is requested, and whether triggered
signaling is allowed.
The SWITCH-LAYER object, which MUST NOT be present unless the INTER-
LAYER object is also present, is optionally used to specify the
switching types and encoding types that define layers that must, or
must not, be used in the computed path. When the SWITCH-LAYER object
is used with the INTER-LAYER object I flag clear (zero), inter-layer
path computation is not allowed, but constraints specified in the
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SWITCH-LAYER object apply. Example usage includes path computation in
a single layer GMPLS network.
The REQ-ADAP-CAP object is optionally used to specify the interface
switching capability of both ends of the lower layer LSP. The REQ-
ADAP-CAP object is used in inter-PCE communication, where the PCE
that is responsible for computing higher layer paths makes a request
as a PCC to a PCE that is responsible for computing lower layer paths.
Alternatively, the REQ-ADAP-CAP object may be used in the NMS-VNTM
model, where the VNTM makes a request as a PCC to a PCE that is
responsible for computing lower-layer paths.
The METRIC object is optionally used to specify metric types to be
optimized or bounded. When metric type 11 (TBC by IANA) is used, it
indicates that path computation MUST minimize or bound the number of
adaptations on a path. When metric type 12 (TBC by IANA) is used, it
indicates that path computation MUST minimize or bound the number of
layers to be involved on a path.
Furthermore, in order to allow different objective functions to be
applied within different network layers, multiple OF objects MAY be
present. In such a case, the first OF object specifies an objective
function for the higher-layer network, and subsequent OF objects
specify objection functions of the subsequent lower-layer networks.
4.2. Path Computation Reply
In the case of successful path computation, the requested PCE replies
to the requesting PCC for the inter-layer path computation result in
a PCRep message that MAY include the INTER-LAYER object. When the
INTER-LAYER object is included in a PCRep message, the I flag, M flag,
and T flag indicate semantics of the path as described in Section 3.1.
Furthermore, when the C flag of the METRIC object in a PCReq is set,
the METRIC object MUST be included in the PCRep to provide the
computed metric value, as specified in [RFC5440].
PCE MAY specify the server layer path information in the ERO. In this
case, the requested PCE replies a PCRep message that includes at
least two sets of ERO information in the path-list, one is for the
client layer path information, and another one is the server layer
path information. When SERVER-INDICATION is included in a PCRep
message, it indicates that the path in the ERO is the server layer
path information. The server layer path specified in the ERO could be
loose or strict. On receiving the replied path, the PCC (e.g. NMS,
ingress node) can trigger the signaling to setup the LSPs according
to the computed paths.
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In the case of unsuccessful path computation, the PCRep message also
contains a NO-PATH object, and the SWITCH-TYPE object and/or the REQ-
ADAP-CAP MAY be used to indicate the set of constraints that could
not be satisfied.
5. Updated Format of PCEP Messages
Message formats in this section, as those in [RFC5440] are presented
using Backus-Naur Format as specified in [RFC5511].
The format of the PCReq message is updated as follows:
<PCReq Message>::= <Common Header>
[<SVEC-list>]
<request-list>
where:
<svec-list>::=<SVEC>
[<svec-list>]
<request-list>::=<request>[<request-list>]
<request>::= <RP>
<END-POINTS>
[<of-list>]
[<LSPA>]
[<BANDWIDTH>]
[<metric-list>]
[<RRO>[<BANDWIDTH>]]
[<IRO>]
[<LOAD-BALANCING>]
[<INTER-LAYER> [<SWITCH-LAYER>]]
[<REQ-ADAP-CAP>]
where:
<of-list>::=<OF>[<of-list>]
<metric-list>::=<METRIC>[<metric-list>]
The format of the PCRep message is updated as follows:
<PCRep Message> ::= <Common Header>
<response-list>
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where:
<response-list>::=<response>[<response-list>]
<response>::=<RP>
[<NO-PATH>]
[<attribute-list>]
[<path-list>]
<path-list>::=<path>[<path-list>]
<path>::= <ERO><attribute-list>
where:
<attribute-list>::=[<of-list>]
[<LSPA>]
[<BANDWIDTH>]
[<metric-list>]
[<IRO>]
[<INTER-LAYER>]
[<SWITCH-LAYER>]
[<REQ-ADAP-CAP>]
[<SERVER-INDICATION>]
<of-list>::=<OF>[<of-list>]
<metric-list>::=<METRIC>[<metric-list>]
6. Manageability Considerations
Manageability of inter-layer traffic engineering with PCE must
address the following consideration for section 5.1.
- need for a MIB module for control and monitoring
- need for built-in diagnostic tools
- configuration implication for the protocol
7. IANA Considerations
7.1. New PCEP Objects
Four new objects: INTER-LAYER object, SWITCH-LAYER object, REQ-ADAP-
CAP and SERVER-INDICATION object.
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INTER-LAYER Object-Class is to be assigned by IANA (recommended
value=18)
INTER-LAYER Object-Type is to be assigned by IANA (recommended
value=1)
SWITCH-LAYER Object-Class is to be assigned by IANA (recommended
value=19)
SWITCH-LAYER Object-Type is to be assigned by IANA (recommended
value=1)
REQ-ADAP-CAP Object-Class is to be assigned by IANA (recommended
value=20)
REQ-ADAP-CAP Object-Type is to be assigned by IANA (recommended
value=1)
SERVER-INDICATION Object-Class is to be assigned by IANA (recommended
value=21)
SERVER-INDICATION Object-Type is to be assigned by IANA (recommended
value=1)
7.2. New Registry for INTER-LAYER Object Flags
IANA is requested to create a registry to manage the Flag field of
the INTER-Layer object.
New bit numbers may be allocated only by an IETF Consensus action.
Each bit should be tracked with the following qualities:
o Bit number (counting from bit 0 as the most significant bit)
o Capability Description
o Defining RFC
Several bits are defined for the INTER-LAYER object flag fields in
this document. The following values have been assigned:
Bit Number Description Reference
29 T flag this document
30 M flag this document
31 I flag this document
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7.3. METRIC Type
Two new metric types are defined in this document for the METRIC
object (specified in [RFC5440]). The IANA is requested to make the
following allocation (suggested value):
- Type 11 : Number of adaptations on a path
- Type 12 : Number of layers on a path
8. Security Considerations
Inter-layer traffic engineering with PCE may raise new security
issues when PCE-PCE communication is done between different layer
networks for inter-layer path computation. Security issues may also
exist when a single PCE is granted full visibility of TE information
that applies to multiple layers.
Path-Key-based mechanism defined in [RFC5520] MAY be applied to
address the topology confidentiality between different layers.
9. Acknowledgments
The authors would like to thank Cyril Margaria for his valuable
comments.
10. References
10.1. Normative References
[RFC2119] S. Bradner, "Key words for use in RFCs to indicate
requirements levels", RFC 2119, March 1997.
[RFC3471] L. Burger, "Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 3471, January 2003.
[RFC3945] E. Mannie, "Generalized Multi-Protocol Label Switching
Architecture", RFC 3945, October 2004.
[RFC4203] K. Kompella and Y. Rekhter, "OSPF Extensions in Support of
Generalized Multi-Protocol Label Switching (GMPLS)", RFC
4203, October 2005.
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[RFC4206] K. Kompella, and Y. Rekhter, "Label Switched Paths (LSP)
Hierarchy with Generalized Multi-Protocol Label Switching
(GMPLS) Traffic Engineering (TE)", RFC 4206, October 2005.
[RFC5440] JP. Vasseur et al, "Path Computation Element (PCE)
Communication Protocol (PCEP)" RFC 5440, March 2009.
[RFC6457] E. Oki et al., "PCC-PCE Communication Requirements for
Inter-Layer Traffic Engineering", RFC6457, December 2011.
[RFC5623] E. Oki et al., "Framework for PCE-Based Inter-Layer MPLS
and GMPLS Traffic Engineering", September 2009.
[RFC5339] JL. Le Roux et al, "Evaluation of Existing GMPLS Protocols
against Multi-Layer and Multi-Region Networks (MLN/MRN)",
RFC5339, September 2008.
10.2. Informative References
[RFC4655] A. Farrel, JP. Vasseur and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655, September 2006.
[RFC5212] K. Shiomoto et al., "Requirements for GMPLS-based multi-
region and multi-layer networks (MRN/MLN)", RFC 5212, July
2008.
[RFC6001] D. Papadimitriou et al., "Generalized Multi-Protocol Label
Switching (GMPLS) Protocol Extensions for Multi-Layer and
Multi-Region Networks (MLN/MRN)", RFC6001, October 2010.
[RFC5150] A. Ayyangar et al., "Label Switched Path Stitching with
Generalized Multiprotocol Label Switching Traffic
Engineering (GMPLS TE)", RFC 5150, February 2008.
[RFC5511] Farrel, A., "Reduced Backus-Naur Form (RBNF) A Syntax Used
in Various Protocol Specifications", April 2009.
11. Authors' Addresses
Eiji Oki
University of Electro-Communications
Tokyo
Japan
Email: oki@ice.uec.ac.jp
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Tomonori Takeda
NTT
3-9-11 Midori-cho,
Musashino-shi, Tokyo 180-8585, Japan
Email: takeda.tomonori@lab.ntt.co.jp
Jean-Louis Le Roux
France Telecom R&D,
Av Pierre Marzin,
22300 Lannion, France
Email: julien.meuric@orange.com
Adrian Farrel
Juniper Networks
Email: adrian@olddog.co.uk
Fatai Zhang
Huawei Technologies Co., Ltd.
F3-5-B R&D Center, Huawei Base,
Bantian, Longgang District
Shenzhen 518129 P.R.China
Phone: +86-755-28972912
Email: zhangfatai@huawei.com
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