draft-ietf-ccamp-gmpls-mln-reqs-06.txt   draft-ietf-ccamp-gmpls-mln-reqs-07.txt 
Network Working Group Kohei Shiomoto (NTT) Network Working Group Kohei Shiomoto (NTT)
Internet-Draft Dimitri Papadimitriou (Alcatel-Lucent) Internet-Draft Dimitri Papadimitriou (Alcatel-Lucent)
Intended Status: Informational Jean-Louis Le Roux (France Telecom) Intended Status: Informational Jean-Louis Le Roux (France Telecom)
Martin Vigoureux (Alcatel-Lucent) Created: November 7, 2007 Martin Vigoureux (Alcatel-Lucent)
Deborah Brungard (AT&T) Expires: May 7, 2008 Deborah Brungard (AT&T)
Expires: April 2008 October 2007
Requirements for GMPLS-based multi-region and Requirements for GMPLS-Based Multi-Region and
multi-layer networks (MRN/MLN) Multi-Layer Networks (MRN/MLN)
draft-ietf-ccamp-gmpls-mln-reqs-06.txt draft-ietf-ccamp-gmpls-mln-reqs-07.txt
Status of this Memo Status of this Memo
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Abstract Abstract
Most of the initial efforts to utilize Generalized MPLS (GMPLS) Most of the initial efforts to utilize Generalized MPLS (GMPLS)
have been related to environments hosting devices with a single have been related to environments hosting devices with a single
switching capability. The complexity raised by the control of such switching capability. The complexity raised by the control of such
data planes is similar to that seen in classical IP/MPLS networks. data planes is similar to that seen in classical IP/MPLS networks.
By extending MPLS to support multiple switching technologies, GMPLS By extending MPLS to support multiple switching technologies, GMPLS
provides a comprehensive framework for the control of a multi- provides a comprehensive framework for the control of a multi-
layered network of either a single switching technology or multiple layered network of either a single switching technology or multiple
switching technologies. switching technologies.
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007
In GMPLS, a switching technology domain defines a region, and a In GMPLS, a switching technology domain defines a region, and a
network of multiple switching types is referred to in this document network of multiple switching types is referred to in this document
as a Multi-Region Network (MRN). When referring in general to a as a Multi-Region Network (MRN). When referring in general to a
layered network, which may consist of either a single or multiple layered network, which may consist of either a single or multiple
regions, this document uses the term, Multi-Layer Network (MLN). regions, this document uses the term, Multi-Layer Network (MLN).
This document defines a framework for GMPLS based multi-
region/multi-layer networks and lists a set of functional
requirements.
Table of Contents draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
1. Introduction ....................................................
1.1. Scope ........................................................ 2.
Conventions Used in this Document ............................... 2.1.
List of Acronyms .............................................. 3.
Positioning ..................................................... 3.1.
Data Plane Layers and Control Plane Regions ................... 3.2.
Service Layer Networks .. ..................................... 3.3.
Vertical and Horizontal Interaction and Integration ........... 3.4.
Motivation .................................................... 4. Key
Concepts of GMPLS-Based MLNs and MRNs ....................... 4.1.
Interface Switching Capability ................................ 4.2.
Multiple Interface Switching Capabilities ..................... 4.2.1.
Networks with Multi-Switching-Type-Capable Hybrid Nodes ..... 4.3.
Integrated Traffic Engineering (TE) and Resource Control ...... 4.3.1.
Triggered Signaling ......................................... 4.3.2.
FA-LSPs ..................................................... 4.3.3.
Virtual Network Topology (VNT) .............................. 5.
Requirements .................................................... 5.1.
Handling Single-Switching and Multi-Switching-Type-Capable
Nodes ....................................................... 5.2.
Advertisement of the Available Adjustment Resource ............ 5.3.
Scalability ................................................... 5.4.
Stability ..................................................... 5.5.
Disruption Minimization ....................................... 5.6.
LSP Attribute Inheritance ..................................... 5.7.
Computing Paths With and Without Nested Signaling ............. 5.8.
LSP Resource Utilization ...................................... 5.8.1.
FA-LSP Release and Setup .................................... 5.8.2.
Virtual TE-Links ............................................ 5.9.
Verification of the LSPs ...................................... 6.
Security Considerations ......................................... 7.
IANA Considerations ............................................ 8.
Acknowledgements ................................................ 9.
References ...................................................... 9.1.
Normative Reference ........................................... 9.2.
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007 This document defines a framework for GMPLS based multi-region/
multi-layer networks and lists a set of functional requirements.
Informative References ........................................ 10. Table of Contents
Authors' Addresses ............................................. 11.
Contributors' Addresses ........................................ 12.
Intellectual Property Considerations ........................... 13.
Full Copyright Statement .......................................
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007 1. Introduction ................................................... 3
1.1. Scope ........................................................ 4
2. Conventions Used in this Document .............................. 5
2.1. List of Acronyms ............................................. 5
3. Positioning .................................................... 5
3.1. Data Plane Layers and Control Plane Regions .................. 6
3.2. Service Layer Networks ....................................... 6
3.3. Vertical and Horizontal Interaction and Integration .......... 7
3.4. Motivation ................................................... 8
4. Key Concepts of GMPLS-Based MLNs and MRNs ...................... 9
4.1. Interface Switching Capability ............................... 9
4.2. Multiple Interface Switching Capabilities ................... 10
4.2.1. Networks with Multi-Switching-Type-Capable Hybrid Nodes ... 10
4.3. Integrated Traffic Engineering (TE) and Resource Control .... 11
4.3.1. Triggered Signaling ....................................... 12
4.3.2. FA-LSPs ................................................... 12
4.3.3. Virtual Network Topology (VNT) ............................ 13
5. Requirements .................................................. 14
5.1. Handling Single-Switching and Multi-Switching-Type-Capable
Nodes ....................................................... 14
5.2. Advertisement of the Available Adjustment Resource .......... 14
5.3. Scalability ................................................. 15
5.4. Stability ................................................... 15
5.5. Disruption Minimization ..................................... 16
5.6. LSP Attribute Inheritance ................................... 16
5.7. Computing Paths With and Without Nested Signaling ........... 17
5.8. LSP Resource Utilization .................................... 18
5.8.1. FA-LSP Release and Setup .................................. 18
5.8.2. Virtual TE-Links .......................................... 19
5.9. Verification of the LSPs .................................... 20
6. Security Considerations ....................................... 20
7. IANA Considerations ........................................... 21
8. Acknowledgements .............................................. 21
9. References .................................................... 21
9.1. Normative Reference ......................................... 21
9.2. Informative References ...................................... 21
10. Authors' Addresses ........................................... 22
11. Contributors' Addresses ...................................... 23
12. Intellectual Property Considerations ......................... 23
13. Full Copyright Statement ..................................... 24
draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
1. Introduction 1. Introduction
Generalized MPLS (GMPLS) extends MPLS to handle multiple switching Generalized MPLS (GMPLS) extends MPLS to handle multiple switching
technologies: packet switching, layer-2 switching, TDM switching, technologies: packet switching, layer-2 switching, TDM switching,
wavelength switching, and fiber switching (see [RFC3945]). The wavelength switching, and fiber switching (see [RFC3945]). The
Interface Switching Capability (ISC) concept is introduced for Interface Switching Capability (ISC) concept is introduced for
these switching technologies and is designated as follows: PSC these switching technologies and is designated as follows: PSC
(packet switch capable), L2SC (Layer-2 switch capable), TDM (Time (packet switch capable), L2SC (Layer-2 switch capable), TDM (Time
Division Multiplex capable), LSC (lambda switch capable), and FSC Division Multiplex capable), LSC (lambda switch capable), and FSC
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In this document, we define a Multi Layer Network (MLN) to be a TE In this document, we define a Multi Layer Network (MLN) to be a TE
domain comprising multiple data plane switching layers either of domain comprising multiple data plane switching layers either of
the same ISC (e.g. TDM) or different ISC (e.g. TDM and PSC) and the same ISC (e.g. TDM) or different ISC (e.g. TDM and PSC) and
controlled by a single GMPLS control plane instance. We further controlled by a single GMPLS control plane instance. We further
define a particular case of MLNs. A Multi Region Network (MRN) is define a particular case of MLNs. A Multi Region Network (MRN) is
defined as a TE domain supporting at least two different switching defined as a TE domain supporting at least two different switching
technologies (e.g., PSC and TDM) hosted on the same devices technologies (e.g., PSC and TDM) hosted on the same devices
(referred to as multi-switching-type-capable LSRs, see below) and (referred to as multi-switching-type-capable LSRs, see below) and
under the control of a single GMPLS control plane instance. under the control of a single GMPLS control plane instance.
MLNs can be further categorized according to the distribution of MLNs can be further categorized according to the distribution of the
the ISCs among the LSRs: ISCs among the LSRs:
- Each LSR may support just one ISC.
Such LSRs are known as single-switching-type-capable LSRs. - Each LSR may support just one ISC. Such LSRs are known as single-
The MLN may comprise a set of single-switching-type-capable LSRs switching-type-capable LSRs. The MLN may comprise a set of single-
some of which support different ISCs. switching-type-capable LSRs some of which support different ISCs.
- Each LSR may support more than one ISC at the same time. - Each LSR may support more than one ISC at the same time.
- Such LSRs are known as multi-switching-type-capable LSRs, and
can be further classified as either "simplex" or "hybrid" nodes
as defined in Section 4.2.
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007 - Such LSRs are known as multi-switching-type-capable LSRs, and can
be further classified as either "simplex" or "hybrid" nodes as
defined in Section 4.2.
- draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
- - The MLN may be constructed from any combination of single-
switching-type-capable LSRs and multi-switching-type-capable - The MLN may be constructed from any combination of single-
LSRs. switching-type-capable LSRs and multi-switching-type-capable LSRs.
Since GMPLS provides a comprehensive framework for the control of Since GMPLS provides a comprehensive framework for the control of
different switching capabilities, a single GMPLS instance may be different switching capabilities, a single GMPLS instance may be used
used to control the MLN/MRN. This enables rapid service to control the MLN/MRN. This enables rapid service provisioning and
provisioning and efficient traffic engineering across all switching efficient traffic engineering across all switching capabilities. In
capabilities. In such networks, TE Links are consolidated into a such networks, TE Links are consolidated into a single Traffic
single Traffic Engineering Database (TED). Since this TED contains Engineering Database (TED). Since this TED contains the information
the information relative to all the different regions and layers relative to all the different regions and layers existing in the
existing in the network, a path across multiple regions or layers network, a path across multiple regions or layers can be computed
can be computed using this TED. Thus optimization of network using this TED. Thus optimization of network resources can be
resources can be achieved across the whole MLN/MRN. achieved across the whole MLN/MRN.
Consider, for example, a MRN consisting of packet- switch capable Consider, for example, a MRN consisting of packet- switch capable
routers and TDM cross-connects. Assume that a packet LSP is routed routers and TDM cross-connects. Assume that a packet LSP is routed
between source and destination packet-switch capable routers, and between source and destination packet-switch capable routers, and
that the LSP can be routed across the PSC-region (i.e., utilizing that the LSP can be routed across the PSC-region (i.e., utilizing
only resources of the packet region topology). If the performance only resources of the packet region topology). If the performance
objective for the packet LSP is not satisfied, new TE links may be objective for the packet LSP is not satisfied, new TE links may be
created between the packet-switch capable routers across the TDM- created between the packet-switch capable routers across the TDM-
region (for example, VC-12 links) and the LSP can be routed over region (for example, VC-12 links) and the LSP can be routed over
those TE links. Furthermore, even if the LSP can be successfully those TE links. Furthermore, even if the LSP can be successfully
established across the PSC-region, TDM hierarchical LSPs across the established across the PSC-region, TDM hierarchical LSPs across the
TDM region between the packet-switch capable routers may be TDM region between the packet-switch capable routers may be
established and used if doing so is necessary to meet the established and used if doing so is necessary to meet the operator's
operator's objectives for network resources availability (e.g., objectives for network resources availability (e.g., link bandwidth).
link bandwidth.The same considerations hold when VC4 LSPs are The same considerations hold when VC4 LSPs are provisioned to provide
provisioned to provide extra flexibility for the VC12 and/or VC11 extra flexibility for the VC12 and/or VC11 layers in an MLN.
layers in an MLN.
1.1. Scope 1.1. Scope
This document describes the requirements to support multi-region/ This document describes the requirements to support multi-region/
multi-layer networks. There is no intention to specify solution- multi-layer networks. There is no intention to specify solution-
specific and/or protocol elements in this document. The specific and/or protocol elements in this document. The applicability
applicability of existing GMPLS protocols and any protocol of existing GMPLS protocols and any protocol extensions to the
extensions to the MRN/MLN is addressed in separate documents [MRN- MRN/MLN is addressed in separate documents [MRN-EVAL].
EVAL].
This document covers the elements of a single GMPLS control plane This document covers the elements of a single GMPLS control plane
instance controlling multiple layers within a given TE domain. A instance controlling multiple layers within a given TE domain. A
control plane instance can serve one, two or more layers. Other control plane instance can serve one, two or more layers. Other
possible approaches such as having multiple control plane instances possible approaches such as having multiple control plane instances
serving disjoint sets of layers are outside the scope of this serving disjoint sets of layers are outside the scope of this
document. It is most probable that such a MLN or MRN would be document. It is most probable that such a MLN or MRN would be
operated by a single Service Provider, but this document does not operated by a single Service Provider, but this document does not
exclude the possibility of two layers (or regions) being under exclude the possibility of two layers (or regions) being under
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007
different administrative control (for example, by different Service different administrative control (for example, by different Service
Providers that share a single control plane instance) where the Providers that share a single control plane instance) where the
administrative domains are prepared to share a limited amount of administrative domains are prepared to share a limited amount of
information. information.
For such TE domain to interoperate with edge nodes/domains draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
supporting non-GMPLS interfaces (such as those defined by other
SDOs), an interworking function may be needed. Location and For such TE domain to interoperate with edge nodes/domains supporting
specification of this function are outside the scope of this non-GMPLS interfaces (such as those defined by other SDOs), an
document (because interworking aspects are strictly under the interworking function may be needed. Location and specification of
responsibility of the interworking function). this function are outside the scope of this document (because
interworking aspects are strictly under the responsibility of the
interworking function).
This document assumes that the interconnection of adjacent MRN/MLN This document assumes that the interconnection of adjacent MRN/MLN
TE domains makes use of [RFC4726] when their edges also support TE domains makes use of [RFC4726] when their edges also support
inter- domain GMPLS RSVP-TE extensions. inter- domain GMPLS RSVP-TE extensions.
2. Conventions Used in this Document 2. Conventions Used in this Document
Although this is not a protocol specification, the key words Although this is not a protocol specification, the key words
"MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
"SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are used in "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are used in
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TDM: Time-Division Switch Capable TDM: Time-Division Switch Capable
TE: Traffic Engineering TE: Traffic Engineering
TED: Traffic Engineering Database TED: Traffic Engineering Database
VNT: Virtual Network Topology VNT: Virtual Network Topology
3. Positioning 3. Positioning
A multi-region network (MRN) is always a multi-layer network (MLN) A multi-region network (MRN) is always a multi-layer network (MLN)
since the network devices on region boundaries bring together since the network devices on region boundaries bring together
different ISCs. A MLN, however, is not necessarily a MRN since different ISCs. A MLN, however, is not necessarily a MRN since
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007
multiple layers could be fully contained within a single region. multiple layers could be fully contained within a single region.
For example, VC12, VC4, and VC4-4c are different layers of the TDM For example, VC12, VC4, and VC4-4c are different layers of the TDM
region. region.
draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
3.1. Data Plane Layers and Control Plane Regions 3.1. Data Plane Layers and Control Plane Regions
A data plane layer is a collection of network resources capable of A data plane layer is a collection of network resources capable of
terminating and/or switching data traffic of a particular format terminating and/or switching data traffic of a particular format
[RFC4397]. These resources can be used for establishing LSPs for [RFC4397]. These resources can be used for establishing LSPs for
traffic delivery. For example, VC-11 and VC4-64c represent two traffic delivery. For example, VC-11 and VC4-64c represent two
different layers. different layers.
From the control plane viewpoint, an LSP region is defined as a set From the control plane viewpoint, an LSP region is defined as a set
of one or more data plane layers that share the same type of of one or more data plane layers that share the same type of
switching technology, that is, the same switching type. For example, switching technology, that is, the same switching type. For example,
VC-11, VC-4, and VC-4-7v layers are part of the same TDM region. VC-11, VC-4, and VC-4-7v layers are part of the same TDM region.
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traffic delivery. For example, VC-11 and VC4-64c represent two traffic delivery. For example, VC-11 and VC4-64c represent two
different layers. different layers.
From the control plane viewpoint, an LSP region is defined as a set From the control plane viewpoint, an LSP region is defined as a set
of one or more data plane layers that share the same type of of one or more data plane layers that share the same type of
switching technology, that is, the same switching type. For example, switching technology, that is, the same switching type. For example,
VC-11, VC-4, and VC-4-7v layers are part of the same TDM region. VC-11, VC-4, and VC-4-7v layers are part of the same TDM region.
The regions that are currently defined are: PSC, L2SC, TDM, LSC, The regions that are currently defined are: PSC, L2SC, TDM, LSC,
and FSC. Hence, an LSP region is a technology domain (identified by and FSC. Hence, an LSP region is a technology domain (identified by
the ISC type) for which data plane resources (i.e., data links) are the ISC type) for which data plane resources (i.e., data links) are
represented into the control plane as an aggregate of TE represented into the control plane as an aggregate of TE information
information associated with a set of links (i.e., TE links). For associated with a set of links (i.e., TE links). For example VC-11
example VC-11 and VC4-64c capable TE links are part of the same TDM and VC4-64c capable TE links are part of the same TDM region.
region. Multiple layers can thus exist in a single region network. Multiple layers can thus exist in a single region network.
Note also that the region may produce a distinction within the Note also that the region may produce a distinction within the
control plane. Layers of the same region share the same switching control plane. Layers of the same region share the same switching
technology and, therefore, use the same set of technology-specific technology and, therefore, use the same set of technology-specific
signaling objects and technology-specific value setting of TE link signaling objects and technology-specific value setting of TE link
attributes within the control plane, but layers from different attributes within the control plane, but layers from different
regions may use different technology-specific objects and TE regions may use different technology-specific objects and TE
attribute values. This means that it may not be possible to simply attribute values. This means that it may not be possible to simply
forward the signaling message between LSR hosting different forward the signaling message between LSR hosting different
switching technologies because change in some of the signaling switching technologies because change in some of the signaling
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A service provider's network may be divided into different service A service provider's network may be divided into different service
layers. The customer's network is considered from the provider's layers. The customer's network is considered from the provider's
perspective as the highest service layer. It interfaces to the perspective as the highest service layer. It interfaces to the
highest service layer of the service provider's network. highest service layer of the service provider's network.
Connectivity across the highest service layer of the service Connectivity across the highest service layer of the service
provider's network may be provided with support from successively provider's network may be provided with support from successively
lower service layers. Service layers are realized via a hierarchy lower service layers. Service layers are realized via a hierarchy
of network layers located generally in several regions and commonly of network layers located generally in several regions and commonly
arranged according to the switching capabilities of network devices. arranged according to the switching capabilities of network devices.
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007
For instance some customers purchase Layer 1 (i.e., transport) For instance some customers purchase Layer 1 (i.e., transport)
services from the service provider, some Layer 2 (e.g., ATM), while services from the service provider, some Layer 2 (e.g., ATM), while
others purchase Layer 3 (IP/MPLS) services. The service provider others purchase Layer 3 (IP/MPLS) services. The service provider
realizes the services by a stack of network layers located within realizes the services by a stack of network layers located within
one or more network regions. The network layers are commonly draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
arranged according to the switching capabilities of the devices in
the networks. Thus, a customer network may be provided on top of one or more network regions. The network layers are commonly arranged
the GMPLS-based multi-region/multi-layer network. For example, a according to the switching capabilities of the devices in the
Layer 1 service (realized via the network layers of TDM, and/or LSC, networks. Thus, a customer network may be provided on top of the
and/or FSC regions) may support a Layer 2 network (realized via ATM GMPLS-based multi-region/multi-layer network. For example, a Layer 1
VP/VC) which may itself support a Layer 3 network (IP/MPLS region). service (realized via the network layers of TDM, and/or LSC, and/or
The supported data plane relationship is a data plane client-server FSC regions) may support a Layer 2 network (realized via ATM VP/VC)
relationship where the lower layer provides a service for the which may itself support a Layer 3 network (IP/MPLS region). The
higher layer using the data links realized in the lower layer. supported data plane relationship is a data plane client-server
relationship where the lower layer provides a service for the higher
layer using the data links realized in the lower layer.
Services provided by a GMPLS-based multi-region/multi-layer network Services provided by a GMPLS-based multi-region/multi-layer network
are referred to as "Multi-region/Multi-layer network services". For are referred to as "Multi-region/Multi-layer network services". For
example, legacy IP and IP/MPLS networks can be supported on top of example, legacy IP and IP/MPLS networks can be supported on top of
multi-region/multi-layer networks. It has to be emphasized that multi-region/multi-layer networks. It has to be emphasized that
delivery of such diverse services is a strong motivator for the delivery of such diverse services is a strong motivator for the
deployment of multi-region/multi-layer networks. deployment of multi-region/multi-layer networks.
A customer network may be provided on top of a server GMPLS-based A customer network may be provided on top of a server GMPLS-based
MRN/MLN which is operated by a service provider. For example, a MRN/MLN which is operated by a service provider. For example, a pure
pure IP and/or an IP/MPLS network can be provided on top of GMPLS- IP and/or an IP/MPLS network can be provided on top of GMPLS-based
based packet over optical networks [MPLS-GMPLS]. The relationship packet over optical networks [MPLS-GMPLS]. The relationship between
between the networks is a client/server relationship and, such the networks is a client/server relationship and, such services are
services are referred to as "MRN/MLN services". In this case, the referred to as "MRN/MLN services". In this case, the customer network
customer network may form part of the MRN/MLN, or may be partially may form part of the MRN/MLN, or may be partially separated, for
separated, for example to maintain separate routing information but example to maintain separate routing information but retain common
retain common signaling. signaling.
3.3. Vertical and Horizontal Interaction and Integration 3.3. Vertical and Horizontal Interaction and Integration
Vertical interaction is defined as the collaborative mechanisms Vertical interaction is defined as the collaborative mechanisms
within a network element that is capable of supporting more than within a network element that is capable of supporting more than one
one layer or region and of realizing the client/server layer or region and of realizing the client/server relationships
relationships between the layers or regions. Protocol exchanges between the layers or regions. Protocol exchanges between two network
between two network controllers managing different regions or controllers managing different regions or layers are also a vertical
layers are also a vertical interaction. Integration of these interaction. Integration of these interactions as part of the control
interactions as part of the control plane is referred to as plane is referred to as vertical integration. Thus, this refers to
vertical integration. Thus, this refers to the collaborative the collaborative mechanisms within a single control plane instance
mechanisms within a single control plane instance driving multiple driving multiple network layers part of the same region or not. Such
network layers part of the same region or not. Such a concept is a concept is useful in order to construct a framework that
useful in order to construct a framework that facilitates efficient facilitates efficient network resource usage and rapid service
network resource usage and rapid service provisioning in carrier provisioning in carrier networks that are based on multiple layers,
networks that are based on multiple layers, switching technologies, switching technologies, or ISCs.
or ISCs.
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007
Horizontal interaction is defined as the protocol exchange between Horizontal interaction is defined as the protocol exchange between
network controllers that manage transport nodes within a given network controllers that manage transport nodes within a given
layer or region. For instance, the control plane interaction layer or region. For instance, the control plane interaction
between two TDM network elements switching at OC-48 is an example between two TDM network elements switching at OC-48 is an example
of horizontal interaction. GMPLS protocol operations handle of horizontal interaction. GMPLS protocol operations handle
horizontal interactions within the same routing area. The case horizontal interactions within the same routing area. The case
draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
where the interaction takes place across a domain boundary, such as where the interaction takes place across a domain boundary, such as
between two routing areas within the same network layer, is between two routing areas within the same network layer, is evaluated
evaluated as part of the inter- domain work [RFC4726], and is as part of the inter- domain work [RFC4726], and is referred to as
referred to as horizontal integration. Thus, horizontal integration horizontal integration. Thus, horizontal integration refers to the
refers to the collaborative mechanisms between network partitions collaborative mechanisms between network partitions and/or
and/or administrative divisions such as routing areas or autonomous administrative divisions such as routing areas or autonomous systems.
systems.
This distinction needs further clarification when administrative This distinction needs further clarification when administrative
domains match layer/region boundaries. Horizontal interaction is domains match layer/region boundaries. Horizontal interaction is
extended to cover such cases. For example, the collaborative extended to cover such cases. For example, the collaborative
mechanisms in place between two lambda switching capable areas mechanisms in place between two lambda switching capable areas relate
relate to horizontal integration. On the other hand, the to horizontal integration. On the other hand, the collaborative
collaborative mechanisms in place between a packet switching mechanisms in place between a packet switching capable (e.g.,
capable (e.g., IP/MPLS) domain and a separate time division IP/MPLS) domain and a separate time division switching capable (e.g.,
switching capable (e.g., VC4 SDH) domain over which it operates are VC4 SDH) domain over which it operates are part of the horizontal
part of the horizontal integration while it can also be seen as a integration while it can also be seen as a first step towards
first step towards vertical integration. vertical integration.
3.4. Motivation 3.4. Motivation
The applicability of GMPLS to multiple switching technologies The applicability of GMPLS to multiple switching technologies
provides a unified control and management approach for both LSP provides a unified control and management approach for both LSP
provisioning and recovery. Indeed, one of the main motivations for provisioning and recovery. Indeed, one of the main motivations for
unifying the capabilities and operations of the GMPLS control plane unifying the capabilities and operations of the GMPLS control plane
is the desire to support multi-LSP-region [RFC4206] routing and is the desire to support multi-LSP-region [RFC4206] routing and
Traffic Engineering (TE) capabilities. For instance, this enables Traffic Engineering (TE) capabilities. For instance, this enables
effective network resource utilization of both the Packet/Layer2 effective network resource utilization of both the Packet/Layer2
LSP regions and the Time Division Multiplexing (TDM) or Lambda LSP LSP regions and the Time Division Multiplexing (TDM) or Lambda LSP
regions in high capacity networks. regions in high capacity networks.
The rationales for GMPLS controlled multi-layer/multi-region The rationales for GMPLS controlled multi-layer/multi-region networks
networks are summarized below: are summarized below:
- The maintenance of multiple instances of the control plane on - The maintenance of multiple instances of the control plane on
devices hosting more than one switching capability not only devices hosting more than one switching capability not only
increases the complexity of their interactions but also increases increases the complexity of their interactions but also increases
the total amount of processing individual instances would handle. the total amount of processing individual instances would handle.
- The unification of the addressing spaces helps in avoiding - The unification of the addressing spaces helps in avoiding
multiple identifiers for the same object (a link, for instance, multiple identifiers for the same object (a link, for instance,
or more generally, any network resource). On the other hand such or more generally, any network resource). On the other hand such
aggregation does not impact the separation between the control aggregation does not impact the separation between the control
plane and the data plane. plane and the data plane.
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007
- By maintaining a single routing protocol instance and a single TE - By maintaining a single routing protocol instance and a single TE
database per LSR, a unified control plane model removes the database per LSR, a unified control plane model removes the
requirement to maintain a dedicated routing topology per layer requirement to maintain a dedicated routing topology per layer
and therefore does not mandate a full mesh of routing adjacencies and therefore does not mandate a full mesh of routing adjacencies
as is the case with overlaid control planes. as is the case with overlaid control planes.
draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
- The collaboration between technology layers where the control - The collaboration between technology layers where the control
channel is associated with the data channel (e.g. packet/framed channel is associated with the data channel (e.g. packet/framed
data planes) and technology layers where the control channel is data planes) and technology layers where the control channel is
not directly associated with the data channel (SONET/SDH, G.709, not directly associated with the data channel (SONET/SDH, G.709,
etc.) is facilitated by the capability within GMPLS to associate etc.) is facilitated by the capability within GMPLS to associate
in-band control plane signaling to the IP terminating interfaces in-band control plane signaling to the IP terminating interfaces
of the control plane. of the control plane.
- Resource management and policies to be applied at the edges of - Resource management and policies to be applied at the edges of
such a MRN/MLN is made more simple (fewer control to management such a MRN/MLN is made more simple (fewer control to management
skipping to change at page 11, line 5 skipping to change at page 9, line 48
[RFC4202]. An ISC is identified via a switching type. [RFC4202]. An ISC is identified via a switching type.
A switching type (also referred to as the switching capability A switching type (also referred to as the switching capability
type) describes the ability of a node to forward data of a type) describes the ability of a node to forward data of a
particular data plane technology, and uniquely identifies a network particular data plane technology, and uniquely identifies a network
region. The following ISC types (and, hence, regions) are defined: region. The following ISC types (and, hence, regions) are defined:
PSC, L2SC, TDM, LSC, and FSC. Each end of a data link (more PSC, L2SC, TDM, LSC, and FSC. Each end of a data link (more
precisely, each interface connecting a data link to a node) in a precisely, each interface connecting a data link to a node) in a
GMPLS network is associated with an ISC. GMPLS network is associated with an ISC.
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007
The ISC value is advertised as a part of the Interface Switching The ISC value is advertised as a part of the Interface Switching
Capability Descriptor (ISCD) attribute (sub-TLV) of a TE link end Capability Descriptor (ISCD) attribute (sub-TLV) of a TE link end
associated with a particular link interface [RFC4202]. Apart from associated with a particular link interface [RFC4202]. Apart from
the ISC, the ISCD contains information including the encoding type, the ISC, the ISCD contains information including the encoding type,
the bandwidth granularity, and the unreserved bandwidth on each of the bandwidth granularity, and the unreserved bandwidth on each of
eight priorities at which LSPs can be established. The ISCD does eight priorities at which LSPs can be established. The ISCD does
not "identify" network layers, it uniquely characterizes not "identify" network layers, it uniquely characterizes
information associated to one or more network layers. information associated to one or more network layers.
draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
TE link end advertisements may contain multiple ISCDs. This can be TE link end advertisements may contain multiple ISCDs. This can be
interpreted as advertising a multi-layer (or multi-switching- interpreted as advertising a multi-layer (or multi-switching-
capable) TE link end. That is, the TE link end (and therefore the capable) TE link end. That is, the TE link end (and therefore the
TE link) is present in multiple layers. TE link) is present in multiple layers.
4.2. Multiple Interface Switching Capabilities 4.2. Multiple Interface Switching Capabilities
In an MLN, network elements may be single-switching-type-capable or In an MLN, network elements may be single-switching-type-capable or
multi-switching-type-capable nodes. Single-switching-type-capable multi-switching-type-capable nodes. Single-switching-type-capable
nodes advertise the same ISC value as part of their ISCD sub-TLV(s) nodes advertise the same ISC value as part of their ISCD sub-TLV(s)
skipping to change at page 11, line 37 skipping to change at page 10, line 28
Link(s). This case is described in [RFC4202]. Link(s). This case is described in [RFC4202].
Multi-switching-type-capable LSRs are classified as "simplex" or Multi-switching-type-capable LSRs are classified as "simplex" or
"hybrid" nodes. Simplex and hybrid nodes are categorized according "hybrid" nodes. Simplex and hybrid nodes are categorized according
to the way they advertise these multiple ISCs: to the way they advertise these multiple ISCs:
- A simplex node can terminate data links with different switching - A simplex node can terminate data links with different switching
capabilities where each data link is connected to the node by a capabilities where each data link is connected to the node by a
separate link interface. So, it advertises several TE Links each separate link interface. So, it advertises several TE Links each
with a single ISC value carried in its ISCD sub-TLV. For example, with a single ISC value carried in its ISCD sub-TLV. For example,
an LSR with PSC and TDM links each of which is connected to the an LSR with PSC and TDM links each of which is connected to the LSR
LSR via a separate interface. via a separate interface.
- A hybrid node can terminate data links with different switching - A hybrid node can terminate data links with different switching
capabilities where the data links are connected to the node by capabilities where the data links are connected to the node by the
the same interface. So, it advertises a single TE Link same interface. So, it advertises a single TE Link containing more
containing more than one ISCD each with a different ISC value. than one ISCD each with a different ISC value. For example, a node
For example, a node may terminate PSC and TDM data links and may terminate PSC and TDM data links and interconnect those
interconnect those external data links via internal links. The external data links via internal links. The external interfaces
external interfaces connected to the node have both PSC and TDM connected to the node have both PSC and TDM capabilities.
capabilities.
Additionally, TE link advertisements issued by a simplex or a
hybrid node may need to provide information about the node's
internal adjustment capacity between the switching technologies
supported. The term "adjustment" capacity refers to the property of
an hybrid node to interconnect different switching capabilities it
provides through its external interfaces.. This information allows
path computation to select an end- to-end multi-layer or multi-
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007
region path that includes links of different switching capabilities Additionally, TE link advertisements issued by a simplex or a hybrid
that are joined by LSRs that can adapt the signal between the links. node may need to provide information about the node's internal
adjustment capacity between the switching technologies supported. The
term "adjustment" capacity refers to the property of an hybrid node
to interconnect different switching capabilities it provides through
its external interfaces.. This information allows path computation to
select an end- to-end multi-layer or multi-region path that includes
links of different switching capabilities that are joined by LSRs
that can adapt the signal between the links.
4.2.1. Networks with Multi-Switching-Type-Capable Hybrid Nodes 4.2.1. Networks with Multi-Switching-Type-Capable Hybrid Nodes
This type of network contains at least one hybrid node, zero or
more simplex nodes, and a set of single-switching-type-capable This type of network contains at least one hybrid node, zero or more
nodes. simplex nodes, and a set of single-switching-type-capable nodes.
Figure 1 shows an example hybrid node. The hybrid node has two Figure 1 shows an example hybrid node. The hybrid node has two
switching elements (matrices), which support, for instance, TDM and switching elements (matrices), which support, for instance, TDM and
PSC switching respectively. The node terminates a PSC and a TDM PSC switching respectively. The node terminates a PSC and a TDM link
link (Link1 and Link2 respectively). It also has an internal link draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
(Link1 and Link2 respectively). It also has an internal link
connecting the two switching elements. connecting the two switching elements.
The two switching elements are internally interconnected in such a The two switching elements are internally interconnected in such a
way that it is possible to terminate some of the resources of, say, way that it is possible to terminate some of the resources of, say,
Link2 and provide adjustment for PSC traffic received/sent over the Link2 and provide adjustment for PSC traffic received/sent over the
PSC interface (#b). This situation is modeled in GMPLS by PSC interface (#b). This situation is modeled in GMPLS by connecting
connecting the local end of Link2 to the TDM switching element via the local end of Link2 to the TDM switching element via an additional
an additional interface realizing the termination/adjustment interface realizing the termination/adjustment function. There are
function. There are two possible ways to set up PSC LSPs through two possible ways to set up PSC LSPs through the hybrid node.
the hybrid node. Available resource advertisement (i.e., Unreserved Available resource advertisement (i.e., Unreserved and Min/Max LSP
and Min/Max LSP Bandwidth) should cover both of these methods. Bandwidth) should cover both of these methods.
Network element Network element
............................. .............................
: -------- : : -------- :
: | PSC | : : | PSC | :
Link1 -------------<->--|#a | : Link1 -------------<->--|#a | :
: | | : : | | :
: +--<->---|#b | : : +--<->---|#b | :
: | -------- : : | -------- :
: | :
: | ---------- : : | ---------- :
TDM : +--<->--|#c TDM | : TDM : +--<->--|#c TDM | :
+PSC : | | : +PSC : | | :
Link2 ------------<->--|#d | : Link2 ------------<->--|#d | :
: ---------- : : ---------- :
:............................ :............................
Figure 1. Hybrid node. Figure 1. Hybrid node.
4.3. Integrated Traffic Engineering (TE) and Resource Control 4.3. Integrated Traffic Engineering (TE) and Resource Control
In GMPLS-based multi-region/multi-layer networks, TE Links may be In GMPLS-based multi-region/multi-layer networks, TE Links may be
consolidated into a single Traffic Engineering Database (TED) for consolidated into a single Traffic Engineering Database (TED) for
use by the single control plane instance. Since this TED contains use by the single control plane instance. Since this TED contains
the information relative to all the layers of all regions in the the information relative to all the layers of all regions in the
network, a path across multiple layers (possibly crossing multiple network, a path across multiple layers (possibly crossing multiple
regions) can be computed using the information in this TED. Thus, regions) can be computed using the information in this TED. Thus,
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007
optimization of network resources across the multiple layers of the optimization of network resources across the multiple layers of the
same region and across multiple regions can be achieved. same region and across multiple regions can be achieved.
These concepts allow for the operation of one network layer over These concepts allow for the operation of one network layer over
the topology (that is, TE links) provided by other network layers the topology (that is, TE links) provided by other network layers
(for example, the use of a lower layer LSC LSP carrying PSC LSPs). (for example, the use of a lower layer LSC LSP carrying PSC LSPs).
In turn, a greater degree of control and inter-working can be In turn, a greater degree of control and inter-working can be
achieved, including (but not limited too): achieved, including (but not limited too):
- Dynamic establishment of Forwarding Adjacency (FA) LSPs draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
[RFC4206] (see Sections 4.3.2 and 4.3.3).
- Provisioning of end-to-end LSPs with dynamic triggering of FA - Dynamic establishment of Forwarding Adjacency (FA) LSPs [RFC4206]
LSPs. (see Sections 4.3.2 and 4.3.3).
Note that in a multi-layer/multi-region network that includes - Provisioning of end-to-end LSPs with dynamic triggering of FA LSPs.
multi- switching-type-capable nodes, an explicit route used to
establish an end-to-end LSP can specify nodes that belong to Note that in a multi-layer/multi-region network that includes multi-
different layers or regions. In this case, a mechanism to control switching-type-capable nodes, an explicit route used to establish an
the dynamic creation of FA-LSPs may be required (see Sections 4.3.2 end-to-end LSP can specify nodes that belong to different layers or
and 4.3.3). regions. In this case, a mechanism to control the dynamic creation of
FA-LSPs may be required (see Sections 4.3.2 and 4.3.3).
There is a full spectrum of options to control how FA-LSPs are There is a full spectrum of options to control how FA-LSPs are
dynamically established. The process can be subject to the control dynamically established. The process can be subject to the control of
of a policy, which may be set by a management component, and which a policy, which may be set by a management component, and which may
may require that the management plane is consulted at the time that require that the management plane is consulted at the time that the
the FA-LSP is established. Alternatively, the FA-LSP can be FA-LSP is established. Alternatively, the FA-LSP can be established
established at the request of the control plane without any at the request of the control plane without any management control.
management control.
4.3.1. Triggered Signaling 4.3.1. Triggered Signaling
When an LSP crosses the boundary from an upper to a lower layer, it When an LSP crosses the boundary from an upper to a lower layer, it
may be nested into a lower layer FA-LSP that crosses the lower may be nested into a lower layer FA-LSP that crosses the lower layer.
layer. From a signaling perspective, there are two alternatives to From a signaling perspective, there are two alternatives to establish
establish the lower layer FA-LSP: static (pre-provisioned) and the lower layer FA-LSP: static (pre-provisioned) and dynamic
dynamic (triggered). A pre-provisioned FA-LSP may be initiated (triggered). A pre-provisioned FA-LSP may be initiated either by the
either by the operator or automatically using features like TE operator or automatically using features like TE auto-mesh [RFC4972].
auto-mesh [RFC4972]. If such a lower layer LSP does not already If such a lower layer LSP does not already exist, the LSP may be
exist, the LSP may be established dynamically. Such a mechanism is established dynamically. Such a mechanism is referred to as
referred to as "triggered signaling". "triggered signaling".
4.3.2. FA-LSPs 4.3.2. FA-LSPs
Once an LSP is created across a layer from one layer border node Once an LSP is created across a layer from one layer border node to
to another, it can be used as a data link in an upper layer. another, it can be used as a data link in an upper layer.
Furthermore, it can be advertised as a TE-link, allowing other
nodes to consider the LSP as a TE link for their path computation
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007
Furthermore, it can be advertised as a TE-link, allowing other nodes
to consider the LSP as a TE link for their path computation
[RFC4206]. An LSP created either statically or dynamically by one [RFC4206]. An LSP created either statically or dynamically by one
instance of the control plane and advertised as a TE link into the instance of the control plane and advertised as a TE link into the
same instance of the control plane is called a Forwarding Adjacency same instance of the control plane is called a Forwarding Adjacency
LSP (FA-LSP). The FA-LSP is advertised as a TE link, and that TE LSP (FA-LSP). The FA-LSP is advertised as a TE link, and that TE link
link is called a Forwarding Adjacency (FA). An FA has the special is called a Forwarding Adjacency (FA). An FA has the special
characteristic of not requiring a routing adjacency (peering) characteristic of not requiring a routing adjacency (peering) between
between its end points yet still guaranteeing control plane its end points yet still guaranteeing control plane connectivity
connectivity between the FA-LSP end points based on a signaling between the FA-LSP end points based on a signaling adjacency. An FA
adjacency. An FA is a useful and powerful tool for improving the is a useful and powerful tool for improving the scalability of GMPLS
scalability of GMPLS Traffic Engineering (TE) capable networks Traffic Engineering (TE) capable networks since multiple higher layer
since multiple higher layer LSPs may be nested (aggregated) over a LSPs may be nested (aggregated) over a single FA-LSP.
single FA-LSP.
The aggregation of LSPs enables the creation of a vertical (nested) draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
LSP Hierarchy. A set of FA-LSPs across or within a lower layer can
be used during path selection by a higher layer LSP. Likewise, the
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007
higher layer LSPs may be carried over dynamic data links realized The aggregation of LSPs enables the creation of a vertical (nested)
via LSPs (just as they are carried over any "regular" static data LSP Hierarchy. A set of FA-LSPs across or within a lower layer can be
links). This process requires the nesting of LSPs through a used during path selection by a higher layer LSP. Likewise, the
hierarchical process [RFC4206]. The TED contains a set of LSP higher layer LSPs may be carried over dynamic data links realized via
advertisements from different layers that are identified by the LSPs (just as they are carried over any "regular" static data links).
ISCD contained within the TE link advertisement associated with the This process requires the nesting of LSPs through a hierarchical
LSP [RFC4202]. process [RFC4206]. The TED contains a set of LSP advertisements from
different layers that are identified by the ISCD contained within the
TE link advertisement associated with the LSP [RFC4202].
If a lower layer LSP is not advertised as an FA, it can still be If a lower layer LSP is not advertised as an FA, it can still be used
used to carry higher layer LSPs across the lower layer. For example, to carry higher layer LSPs across the lower layer. For example, if
if the LSP is set up using triggered signaling, it will be used to the LSP is set up using triggered signaling, it will be used to carry
carry the higher layer LSP that caused the trigger. Further, the the higher layer LSP that caused the trigger. Further, the lower
lower layer remains available for use by other higher layer LSPs layer remains available for use by other higher layer LSPs arriving
arriving at the boundary. at the boundary.
Under some circumstances it may be useful to control the Under some circumstances it may be useful to control the
advertisement of LSPs as FAs during the signaling establishment of advertisement of LSPs as FAs during the signaling establishment of
the LSPs [DYN-HIER]. the LSPs [DYN-HIER].
4.3.3. Virtual Network Topology (VNT) 4.3.3. Virtual Network Topology (VNT)
A set of one or more of lower-layer LSPs provides information for A set of one or more of lower-layer LSPs provides information for
efficient path handling in upper-layer(s) of the MLN, or, in other efficient path handling in upper-layer(s) of the MLN, or, in other
words, provides a virtual network topology (VNT) to the upper- words, provides a virtual network topology (VNT) to the upper-layers.
layers. For instance, a set of LSPs, each of which is supported by For instance, a set of LSPs, each of which is supported by an LSC
an LSC LSP, provides a virtual network topology to the layers of a LSP, provides a virtual network topology to the layers of a PSC
PSC region, assuming that the PSC region is connected to the LSC region, assuming that the PSC region is connected to the LSC region.
region. Note that a single lower-layer LSP is a special case of the Note that a single lower-layer LSP is a special case of the VNT. The
VNT. The virtual network topology is configured by setting up or virtual network topology is configured by setting up or tearing down
tearing down the lower layer LSPs. By using GMPLS signaling and the lower layer LSPs. By using GMPLS signaling and routing protocols,
routing protocols, the virtual network topology can be adapted to the virtual network topology can be adapted to traffic demands.
traffic demands.
A lower-layer LSP appears as a TE-link in the VNT. Whether the A lower-layer LSP appears as a TE-link in the VNT. Whether the
diversely-routed lower-layer LSPs are used or not, the routes of diversely-routed lower-layer LSPs are used or not, the routes of
lower-layer LSPs are hidden from the upper layer in the VNT. Thus, lower-layer LSPs are hidden from the upper layer in the VNT. Thus,
the VNT simplifies the upper-layer routing and traffic engineering the VNT simplifies the upper-layer routing and traffic engineering
decisions by hiding the routes taken by the lower-layer LSPs. decisions by hiding the routes taken by the lower-layer LSPs.
However, hiding the routes of the lower-layer LSPs may lose However, hiding the routes of the lower-layer LSPs may lose important
important information that is needed to make the higher-layer LSPs information that is needed to make the higher-layer LSPs reliable.
reliable. For instance, the routing and traffic engineering in the For instance, the routing and traffic engineering in the IP/MPLS
IP/MPLS layer does not usually consider how the IP/MPLS TE links layer does not usually consider how the IP/MPLS TE links are formed
are formed from optical paths that are routed in the fiber layer. from optical paths that are routed in the fiber layer. Two optical
Two optical paths may share the same fiber link in the lower-layer paths may share the same fiber link in the lower-layer and therefore
and therefore they may both fail if the fiber link is cut. Thus the they may both fail if the fiber link is cut. Thus the shared risk
shared risk properties of the TE links in the VNT must be made properties of the TE links in the VNT must be made available to the
available to the higher layer during path computation. Further, the higher layer during path computation. Further, the topology of the
topology of the VNT should be designed so that any single fiber cut VNT should be designed so that any single fiber cut does not bisect
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007 draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
does not bisect the VNT. These issues are addressed later in this the VNT. These issues are addressed later in this document.
document.
Reconfiguration of the virtual network topology may be triggered by Reconfiguration of the virtual network topology may be triggered by
traffic demand changes, topology configuration changes, signaling traffic demand changes, topology configuration changes, signaling
requests from the upper layer, and network failures. For instance, requests from the upper layer, and network failures. For instance,
by reconfiguring the virtual network topology according to the by reconfiguring the virtual network topology according to the
traffic demand between source and destination node pairs, network traffic demand between source and destination node pairs, network
performance factors, such as maximum link utilization and residual performance factors, such as maximum link utilization and residual
capacity of the network, can be optimized. Reconfiguration is capacity of the network, can be optimized. Reconfiguration is
performed by computing the new VNT from the traffic demand matrix performed by computing the new VNT from the traffic demand matrix
and optionally from the current VNT. Exact details are outside the and optionally from the current VNT. Exact details are outside the
scope of this document. However, this method may be tailored scope of this document. However, this method may be tailored
according to the service provider's policy regarding network according to the service provider's policy regarding network
performance and quality of service (delay, loss/disruption, performance and quality of service (delay, loss/disruption,
utilization, residual capacity, reliability). utilization, residual capacity, reliability).
5. Requirements 5. Requirements
5.1. Handling Single-Switching and Multi-Switching-Type-Capable Nodes 5.1. Handling Single-Switching and Multi-Switching-Type-Capable Nodes
The MRN/MLN can consist of single-switching-type-capable and
multi- switching-type-capable nodes. The path computation mechanism The MRN/MLN can consist of single-switching-type-capable and multi-
in the MLN SHOULD be able to compute paths consisting of any switching-type-capable nodes. The path computation mechanism in the
combination of such nodes. MLN SHOULD be able to compute paths consisting of any combination of
such nodes.
Both single-switching-type-capable and multi-switching-type-capable Both single-switching-type-capable and multi-switching-type-capable
(simplex or hybrid) nodes could play the role of layer boundary. (simplex or hybrid) nodes could play the role of layer boundary.
MRN/MLN Path computation SHOULD handle TE topologies built of any MRN/MLN Path computation SHOULD handle TE topologies built of any
combination of nodes. combination of nodes.
5.2. Advertisement of the Available Adjustment Resource 5.2. Advertisement of the Available Adjustment Resource
A hybrid node SHOULD maintain resources on its internal links (the A hybrid node SHOULD maintain resources on its internal links (the
links required for vertical (layer) integration) and SHOULD links required for vertical (layer) integration) and SHOULD advertise
advertise the resource information for those links. Likewise, path the resource information for those links. Likewise, path computation
computation elements SHOULD be prepared to use the availability of elements SHOULD be prepared to use the availability of termination/
termination/ adjustment resources as a constraint in MRN/MLN path adjustment resources as a constraint in MRN/MLN path computations to
computations to reduce the higher layer LSP setup blocking reduce the higher layer LSP setup blocking probability caused by the
probability caused by the lack of necessary termination/adjustment lack of necessary termination/adjustment resources in the lower
resources in the lower layer(s). layer(s).
The advertisement of the adjustment capability to terminate LSPs of The advertisement of the adjustment capability to terminate LSPs of
lower-region and forward traffic in the upper-region is REQUIRED, lower-region and forward traffic in the upper-region is REQUIRED, as
as it provides critical information when performing multi-region it provides critical information when performing multi-region path
path computation. computation.
The mechanism SHOULD cover the case where the upper-layer links The mechanism SHOULD cover the case where the upper-layer links which
which are directly connected to upper-layer switching element and are directly connected to upper-layer switching element and the ones
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007 which are connected through internal links between upper-layer
element and lower-layer element coexist (see Section 4.2.1).
the ones which are connected through internal links between upper- draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
layer element and lower-layer element coexist (see Section 4.2.1).
5.3. Scalability 5.3. Scalability
The MRN/MLN relies on unified routing and traffic engineering The MRN/MLN relies on unified routing and traffic engineering models.
models.
- Unified routing model: By maintaining a single routing protocol - Unified routing model: By maintaining a single routing protocol
instance and a single TE database per LSR, a unified control instance and a single TE database per LSR, a unified control plane
plane model removes the requirement to maintain a dedicated model removes the requirement to maintain a dedicated routing
routing topology per layer, and therefore does not mandate a topology per layer, and therefore does not mandate a full mesh of
full mesh of routing adjacencies per layer. routing adjacencies per layer.
- Unified TE model: The TED in each LSR is populated with TE-links - Unified TE model: The TED in each LSR is populated with TE-links
from all layers of all regions (TE link interfaces on multiple- from all layers of all regions (TE link interfaces on multiple-
switching-capability LSRs can be advertised with multiple ISCDs). switching-capability LSRs can be advertised with multiple ISCDs).
This may lead to an increase in the amount of information that This may lead to an increase in the amount of information that has
has to be flooded and stored within the network. to be flooded and stored within the network.
Furthermore, path computation times, which may be of great Furthermore, path computation times, which may be of great importance
importance during restoration, will depend on the size of the TED. during restoration, will depend on the size of the TED.
Thus MRN/MLN routing mechanisms MUST be designed to scale well with Thus MRN/MLN routing mechanisms MUST be designed to scale well with
an increase of any of the following: an increase of any of the following:
- Number of nodes - Number of nodes
- Number of TE-links (including FA-LSPs) - Number of TE-links (including FA-LSPs)
- Number of LSPs - Number of regions and layers - Number of LSPs
- Number of regions and layers
- Number of ISCDs per TE-link. - Number of ISCDs per TE-link.
Further, design of the routing protocols MUST NOT prevent TE Further, design of the routing protocols MUST NOT prevent TE
information filtering based on ISCDs. The path computation information filtering based on ISCDs. The path computation mechanism
mechanism and the signaling protocol SHOULD be able to operate on and the signaling protocol SHOULD be able to operate on partial TE
partial TE information. information.
Since TE Links can advertise multiple Interface Switching Since TE Links can advertise multiple Interface Switching
Capabilities (ISCs), the number of links can be limited (by Capabilities (ISCs), the number of links can be limited (by
combination) by using specific topological maps referred to as VNT combination) by using specific topological maps referred to as VNTs
(Virtual Network Topologies). The introduction of virtual (Virtual Network Topologies). The introduction of virtual topological
topological maps leads us to consider the concept of emulation of maps leads us to consider the concept of emulation of data plane
data plane overlays. overlays.
5.4. Stability 5.4. Stability
Path computation is dependent on the network topology and Path computation is dependent on the network topology and associated
associated link state. The path computation stability of an upper link state. The path computation stability of an upper layer may be
layer may be impaired if the VNT changes frequently and/or if the impaired if the VNT changes frequently and/or if the status and TE
status and TE parameters (the TE metric, for instance) of links in parameters (the TE metric, for instance) of links in the VNT changes
the VNT changes frequently. In this context, robustness of the VNT frequently. In this context, robustness of the VNT is defined as the
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007 capability to smooth changes that may occur and avoid their
propagation into higher layers. Changes to the VNT may be caused by
the creation, deletion, or modification of LSPs.
is defined as the capability to smooth changes that may occur and draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
avoid their propagation into higher layers. Changes to the VNT may
be caused by the creation, deletion, or modification of LSPs.
Creation, deletion, and modification of LSPs MAY be triggered by Creation, deletion, and modification of LSPs MAY be triggered by
adjacent layers or through operational actions to meet traffic adjacent layers or through operational actions to meet traffic demand
demand changes, topology changes, signaling requests from the upper changes, topology changes, signaling requests from the upper layer,
layer, and network failures. Routing robustness SHOULD be traded and network failures. Routing robustness SHOULD be traded with
with adaptability with respect to the change of incoming traffic adaptability with respect to the change of incoming traffic requests.
requests.
5.5. Disruption Minimization 5.5. Disruption Minimization
When reconfiguring the VNT according to a change in traffic demand, When reconfiguring the VNT according to a change in traffic demand,
the upper-layer LSP might be disrupted. Such disruption to the the upper-layer LSP might be disrupted. Such disruption to the upper
upper layers MUST be minimized. layers MUST be minimized.
When residual resource decreases to a certain level, some lower When residual resource decreases to a certain level, some lower layer
layer LSPs MAY be released according to local or network policies. LSPs MAY be released according to local or network policies. There is
There is a trade-off between minimizing the amount of resource a trade-off between minimizing the amount of resource reserved in the
reserved in the lower layer and disrupting higher layer traffic lower layer and disrupting higher layer traffic (i.e., moving the
(i.e. moving the traffic to other TE-LSPs so that some LSPs can be traffic to other TE-LSPs so that some LSPs can be released). Such
released). Such traffic disruption MAY be allowed, but MUST be traffic disruption MAY be allowed, but MUST be under the control of
under the control of policy that can be configured by the operator. policy that can be configured by the operator. Any repositioning of
Any repositioning of traffic MUST be as non-disruptive as possible traffic MUST be as non-disruptive as possible (for example, using
(for example, using make-before-break). make-before-break).
5.6. LSP Attribute Inheritance 5.6. LSP Attribute Inheritance
TE-Link parameters SHOULD be inherited from the parameters of the TE-Link parameters SHOULD be inherited from the parameters of the LSP
LSP that provides the TE-link, and so from the TE-links in the that provides the TE-link, and so from the TE-links in the lower
lower layer that are traversed by the LSP. layer that are traversed by the LSP.
These include: These include:
- Interface Switching Capability - Interface Switching Capability
- TE metric - TE metric
- Maximum LSP bandwidth per priority level - Maximum LSP bandwidth per priority level
- Unreserved bandwidth for all priority levels - Unreserved bandwidth for all priority levels
- Maximum Reservable bandwidth - Maximum Reservable bandwidth
- Protection attribute - Protection attribute
- Minimum LSP bandwidth (depending on the Switching Capability) - Minimum LSP bandwidth (depending on the Switching Capability)
- SRLG - SRLG
Inheritance rules MUST be applied based on specific policies. Inheritance rules MUST be applied based on specific policies.
Particular attention should be given to the inheritance of TE Particular attention should be given to the inheritance of TE metric
metric (which may be other than a strict sum of the metrics of the (which may be other than a strict sum of the metrics of the component
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007 TE links at the lower layer), protection attributes, and SRLG.
component TE links at the lower layer), protection attributes, and
SRLG.
As described earlier, hiding the routes of the lower-layer LSPs may As described earlier, hiding the routes of the lower-layer LSPs may
lose important information necessary to make LSPs in the higher lose important information necessary to make LSPs in the higher layer
layer network reliable. SRLGs may be used to identify which lower- network reliable. SRLGs may be used to identify which lower-layer
layer LSPs share the same failure risk so that the potential risk LSPs share the same failure risk so that the potential risk of the
of the VNT becoming disjoint can be minimized, and so that resource VNT becoming disjoint can be minimized, and so that resource disjoint
disjoint protection paths can be set up in the higher layer. How to protection paths can be set up in the higher layer. How to inherit
inherit the SRLG information from the lower layer to the upper draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
layer needs more discussion and is out of scope of this document.
the SRLG information from the lower layer to the upper layer needs
more discussion and is out of scope of this document.
5.7. Computing Paths With and Without Nested Signaling 5.7. Computing Paths With and Without Nested Signaling
Path computation MAY take into account LSP region and layer Path computation MAY take into account LSP region and layer
boundaries when computing a path for an LSP. For example, path boundaries when computing a path for an LSP. For example, path
computation MAY restrict the path taken by an LSP to only the links computation MAY restrict the path taken by an LSP to only the links
whose interface switching capability is PSC. whose interface switching capability is PSC.
Interface switching capability is used as a constraint in path Interface switching capability is used as a constraint in path
computation. For example, a TDM-LSP is routed over the topology computation. For example, a TDM-LSP is routed over the topology
composed of TE links of the same TDM layer. In calculating the path composed of TE links of the same TDM layer. In calculating the path
for the LSP, the TED MAY be filtered to include only links where for the LSP, the TED MAY be filtered to include only links where both
both end include requested LSP switching type. In this way end include requested LSP switching type. In this way hierarchical
hierarchical routing is done by using a TED filtered with respect routing is done by using a TED filtered with respect to switching
to switching capability (that is, with respect to particular layer). capability (that is, with respect to particular layer).
If triggered signaling is allowed, the path computation mechanism If triggered signaling is allowed, the path computation mechanism MAY
MAY produce a route containing multiple layers/regions. The path is produce a route containing multiple layers/regions. The path is
computed over the multiple layers/regions even if the path is not computed over the multiple layers/regions even if the path is not
"connected" in the same layer as the endpoints of the path exist. "connected" in the same layer as the endpoints of the path exist.
Note that here we assume that triggered signaling will be invoked Note that here we assume that triggered signaling will be invoked to
to make the path "connected", when the upper-layer signaling make the path "connected", when the upper-layer signaling request
request arrives at the boundary node. arrives at the boundary node.
The upper-layer signaling request may contain an ERO that includes The upper-layer signaling request may contain an ERO that includes
only hops in the upper layer, in which case the boundary node is only hops in the upper layer, in which case the boundary node is
responsible for triggered creation of the lower-layer FA-LSP using responsible for triggered creation of the lower-layer FA-LSP using a
a path of its choice, or for the selection of any available lower path of its choice, or for the selection of any available lower layer
layer LSP as a data link for the higher layer. This mechanism is LSP as a data link for the higher layer. This mechanism is
appropriate for environments where the TED is filtered in the appropriate for environments where the TED is filtered in the higher
higher layer, where separate routing instances are used per layer, layer, where separate routing instances are used per layer, or where
or where administrative policies prevent the higher layer from administrative policies prevent the higher layer from specifying
specifying paths through the lower layer. paths through the lower layer.
Obviously, if the lower layer LSP has been advertised as a TE link Obviously, if the lower layer LSP has been advertised as a TE link
(virtual or real) into the higher layer, then the higher layer (virtual or real) into the higher layer, then the higher layer
signaling request may contain the TE link identifier and so signaling request may contain the TE link identifier and so indicate
indicate the lower layer resources to be used. But in this case, the lower layer resources to be used. But in this case, the path of
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007 the lower layer LSP can be dynamically changed by the lower layer at
any time.
the path of the lower layer LSP can be dynamically changed by the
lower layer at any time.
Alternatively, the upper-layer signaling request may contain an ERO Alternatively, the upper-layer signaling request may contain an ERO
specifying the lower layer FA-LSP route. In this case, the boundary specifying the lower layer FA-LSP route. In this case, the boundary
node is responsible for decision as to which it should use the path node is responsible for decision as to which it should use the path
contained in the strict ERO or it should re-compute the path within contained in the strict ERO or it should re-compute the path within
in the lower-layer. in the lower-layer.
Even in case the lower-layer FA-LSPs are already established, a Even in case the lower-layer FA-LSPs are already established, a
draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
signaling request may also be encoded as loose ERO. In this signaling request may also be encoded as loose ERO. In this
situation, it is up to the boundary node to decide whether it situation, it is up to the boundary node to decide whether it should
should a new lower-layer FA-LSP or it should use the existing a new lower-layer FA-LSP or it should use the existing lower-layer
lower-layer FA-LSPs. FA-LSPs.
The lower-layer FA-LSP can be advertised just as an FA-LSP in the The lower-layer FA-LSP can be advertised just as an FA-LSP in the
upper-layer or an IGP adjacency can be brought up on the lower- upper-layer or an IGP adjacency can be brought up on the lower-layer
layer FA-LSP. FA-LSP.
5.8. LSP Resource Utilization 5.8. LSP Resource Utilization
It MUST be possible to utilize network resources efficiently. It MUST be possible to utilize network resources efficiently.
Particularly, resource usage in all layers SHOULD be optimized as a Particularly, resource usage in all layers SHOULD be optimized as a
whole (i.e., across all layers), in a coordinated manner, (i.e., whole (i.e., across all layers), in a coordinated manner, (i.e.,
taking all layers into account). The number of lower-layer LSPs taking all layers into account). The number of lower-layer LSPs
carrying upper-layer LSPs SHOULD be minimized (note that multiple carrying upper-layer LSPs SHOULD be minimized (note that multiple
LSPs MAY be used for load balancing). Lower-layer LSPs that could LSPs MAY be used for load balancing). Lower-layer LSPs that could
have their traffic re-routed onto other LSPs are unnecessary and have their traffic re-routed onto other LSPs are unnecessary and
SHOULD be avoided. SHOULD be avoided.
5.8.1. FA-LSP Release and Setup 5.8.1. FA-LSP Release and Setup
Statistical multiplexing can only be employed in PSC and L2SC Statistical multiplexing can only be employed in PSC and L2SC
regions. A PSC or L2SC LSP may or may not consume the maximum regions. A PSC or L2SC LSP may or may not consume the maximum
reservable bandwidth of the TE link (FA-LSP) that carries it. On reservable bandwidth of the TE link (FA-LSP) that carries it. On the
the other hand, a TDM, or LSC LSP always consumes a fixed amount of other hand, a TDM, or LSC LSP always consumes a fixed amount of
bandwidth as long as it exists (and is fully instantiated) because bandwidth as long as it exists (and is fully instantiated) because
statistical multiplexing is not available. statistical multiplexing is not available.
If there is low traffic demand, some FA-LSPs that do not carry any If there is low traffic demand, some FA-LSPs that do not carry any
higher-layer LSP MAY be released so that lower-layer resources are higher-layer LSP MAY be released so that lower-layer resources are
released and can be assigned to other uses. Note that if a small released and can be assigned to other uses. Note that if a small
fraction of the available bandwidth of an FA-LSP is still in use, fraction of the available bandwidth of an FA-LSP is still in use, the
the nested LSPs can also be re-routed to other FA-LSPs (optionally nested LSPs can also be re-routed to other FA-LSPs (optionally using
using the make-before-break technique) to completely free up the the make-before-break technique) to completely free up the FA-LSP.
FA-LSP. Alternatively, unused FA-LSPs MAY be retained for future Alternatively, unused FA-LSPs MAY be retained for future use. Release
use. Release or retention of underutilized FA-LSPs is a policy or retention of underutilized FA-LSPs is a policy decision.
decision.
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007
As part of the re-optimization process, the solution MUST allow As part of the re-optimization process, the solution MUST allow
rerouting of an FA-LSP while keeping interface identifiers of rerouting of an FA-LSP while keeping interface identifiers of
corresponding TE links unchanged. Further, this process MUST be corresponding TE links unchanged. Further, this process MUST be
possible while the FA-LSP is carrying traffic (higher layer LSPs) possible while the FA-LSP is carrying traffic (higher layer LSPs)
with minimal disruption to the traffic. with minimal disruption to the traffic.
Additional FA-LSPs MAY also be created based on policy, which might Additional FA-LSPs MAY also be created based on policy, which might
consider residual resources and the change of traffic demand across consider residual resources and the change of traffic demand across
the region. By creating the new FA-LSPs, the network performance the region. By creating the new FA-LSPs, the network performance such
such as maximum residual capacity may increase. as maximum residual capacity may increase.
draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
As the number of FA-LSPs grows, the residual resource may decrease. As the number of FA-LSPs grows, the residual resource may decrease.
In this case, re-optimization of FA-LSPs MAY be invoked according In this case, re-optimization of FA-LSPs MAY be invoked according to
to policy. policy.
Any solution MUST include measures to protect against network Any solution MUST include measures to protect against network
destabilization caused by the rapid setup and teardown of LSPs as destabilization caused by the rapid setup and teardown of LSPs as
traffic demand varies near a threshold. traffic demand varies near a threshold.
Signaling of lower-layer LSPs SHOULD include a mechanism to rapidly Signaling of lower-layer LSPs SHOULD include a mechanism to rapidly
advertise the LSP as a TE link and to coordinate into which routing advertise the LSP as a TE link and to coordinate into which routing
instances the TE link should be advertised. instances the TE link should be advertised.
5.8.2. Virtual TE-Links 5.8.2. Virtual TE-Links
It may be considered disadvantageous to fully instantiate (i.e. It may be considered disadvantageous to fully instantiate (i.e. pre-
pre- provision) the set of lower layer LSPs that provide the VNT provision) the set of lower layer LSPs that provide the VNT since
since this might reserve bandwidth that could be used for other this might reserve bandwidth that could be used for other LSPs in the
LSPs in the absence of upper-layer traffic. absence of upper-layer traffic.
However, in order to allow path computation of upper-layer LSPs However, in order to allow path computation of upper-layer LSPs
across the lower-layer, the lower-layer LSPs MAY be advertised into across the lower-layer, the lower-layer LSPs MAY be advertised into
the upper-layer as though they had been fully established, but the upper-layer as though they had been fully established, but
without actually establishing them. Such TE links that represent without actually establishing them. Such TE links that represent
the possibility of an underlying LSP are termed "virtual TE-links." the possibility of an underlying LSP are termed "virtual TE-links."
It is an implementation choice at a layer boundary node whether to It is an implementation choice at a layer boundary node whether to
create real or virtual TE-links, and the choice if available in an create real or virtual TE-links, and the choice if available in an
implementation MUST be under the control of operator policy. Note implementation MUST be under the control of operator policy. Note
that there is no requirement to support the creation of virtual TE- that there is no requirement to support the creation of virtual TE-
links, since real TE-links (with established LSPs) may be used, and links, since real TE-links (with established LSPs) may be used, and
even if there are no TE-links (virtual or real) advertised to the even if there are no TE-links (virtual or real) advertised to the
higher layer, it is possible to route a higher layer LSP into a higher layer, it is possible to route a higher layer LSP into a
lower layer on the assumptions that proper hierarchical LSPs in the lower layer on the assumptions that proper hierarchical LSPs in the
lower layer will be dynamically created (triggered) as needed. lower layer will be dynamically created (triggered) as needed.
If an upper-layer LSP that makes use of a virtual TE-Link is set up, If an upper-layer LSP that makes use of a virtual TE-Link is set up,
the underlying LSP MUST be immediately signaled in the lower layer. the underlying LSP MUST be immediately signaled in the lower layer.
If virtual TE-Links are used in place of pre-established LSPs, the If virtual TE-Links are used in place of pre-established LSPs, the
TE-links across the upper-layer can remain stable using pre- TE-links across the upper-layer can remain stable using pre-computed
computed paths while wastage of bandwidth within the lower-layer paths while wastage of bandwidth within the lower-layer and
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007 unnecessary reservation of adaptation resource at the border nodes
can be avoided.
and unnecessary reservation of adaptation resource at the border
nodes can be avoided.
The solution SHOULD provide operations to facilitate the build-up The solution SHOULD provide operations to facilitate the build-up of
of such virtual TE-links, taking into account the (forecast) such virtual TE-links, taking into account the (forecast) traffic
traffic demand and available resource in the lower-layer. demand and available resource in the lower-layer.
Virtual TE-links MAY be added, removed or modified dynamically (by Virtual TE-links MAY be added, removed or modified dynamically (by
changing their capacity) according to the change of the (forecast) changing their capacity) according to the change of the (forecast)
traffic demand and the available resource in the lower-layer. The traffic demand and the available resource in the lower-layer. The
draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
maximum number of virtual TE links that can be defined SHOULD be maximum number of virtual TE links that can be defined SHOULD be
configurable. configurable.
Any solution MUST include measures to protect against network Any solution MUST include measures to protect against network
destabilization caused by the rapid changes in the virtual network destabilization caused by the rapid changes in the virtual network
topology as traffic demand varies near a threshold. topology as traffic demand varies near a threshold.
The concept of the VNT can be extended to allow the virtual TE- The concept of the VNT can be extended to allow the virtual TE-links
links to form part of the VNT. The combination of the fully to form part of the VNT. The combination of the fully provisioned TE-
provisioned TE- links and the virtual TE-links defines the VNT links and the virtual TE-links defines the VNT provided by the lower
provided by the lower layer. The VNT can be changed by setting up layer. The VNT can be changed by setting up and/or tearing down
and/or tearing down virtual TE links as well as by modifying real virtual TE links as well as by modifying real links (i.e., the fully
links (i.e., the fully provisioned LSPs). How to design the VNT and provisioned LSPs). How to design the VNT and how to manage it are out
how to manage it are out of scope of this document. of scope of this document.
In some situations, selective advertisement of the preferred In some situations, selective advertisement of the preferred
connectivity among a set of border nodes between layers may be connectivity among a set of border nodes between layers may be
appropriate. Further decreasing the number of advertisement of the appropriate. Further decreasing the number of advertisement of the
virtual connectivity can be achieved by abstracting the topology virtual connectivity can be achieved by abstracting the topology
(between border nodes) using models similar to those detailed in (between border nodes) using models similar to those detailed in
[RFC4847]. [RFC4847].
5.9. Verification of the LSPs 5.9. Verification of the LSPs
When a lower layer LSP is established for use as a data link by a When a lower layer LSP is established for use as a data link by a
higher layer, the LSP MAY be verified for correct connectivity and higher layer, the LSP MAY be verified for correct connectivity and
data integrity. Such mechanisms are data technology-specific and data integrity. Such mechanisms are data technology-specific and are
are beyond the scope of this document, but may be coordinated beyond the scope of this document, but may be coordinated through the
through the GMPLS control plane. GMPLS control plane.
6. Security Considerations 6. Security Considerations
The MLN/MRN architecture does not introduce any new security The MLN/MRN architecture does not introduce any new security
requirements over the general GMPLS architecture described in requirements over the general GMPLS architecture described in
[RFC3945]. Additional security considerations form MPLS and GMPLS [RFC3945]. Additional security considerations form MPLS and GMPLS
networks are described in [MPLS-SEC]. networks are described in [MPLS-SEC].
However, where the separate layers of a MLN/MRN network are However, where the separate layers of a MLN/MRN network are operated
operated as different administrative domains, additional security as different administrative domains, additional security
considerations may be given to the mechanisms for allowing inter- considerations may be given to the mechanisms for allowing inter-
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007
layer LSP setup, for triggering lower-layer LSPs, or for VNT layer LSP setup, for triggering lower-layer LSPs, or for VNT
management. Similarly, consideration may be given to the amount of management. Similarly, consideration may be given to the amount of
information shared between administrative domains, and the trade- information shared between administrative domains, and the trade-
off between multi-layer TE and confidentiality of information off between multi-layer TE and confidentiality of information
belonging to each administrative domain. belonging to each administrative domain.
It is expected that solution documents will include a full analysis It is expected that solution documents will include a full analysis
of the security issues that any protocol extensions introduce. of the security issues that any protocol extensions introduce.
draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
7. IANA Considerations 7. IANA Considerations
This informational document makes no requests to IANA for action. This informational document makes no requests to IANA for action.
8. Acknowledgements 8. Acknowledgements
The authors would like to thank Adrian Farrel and the participants The authors would like to thank Adrian Farrel and the participants
of ITU-T Study Group 15 Question 14 for their careful review. of ITU-T Study Group 15 Question 14 for their careful review.
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007
9. References 9. References
9.1. Normative Reference 9.1. Normative Reference
[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, March 1997.
[RFC3945] E. Mannie (Editor), "Generalized Multi-Protocol Label
Switching (GMPLS) Architecture", RFC 3945, October 2004.
[RFC4202] Kompella, K., and Rekhter, Y., "Routing Extensions in [RFC4202] Kompella, K., and Rekhter, Y., "Routing Extensions in
Support of Generalized Multi-Protocol Label Switching Support of Generalized Multi-Protocol Label Switching
(GMPLS)," RFC4202, October 2005. (GMPLS)," RFC4202, October 2005.
[RFC4726] Farrel, A., Vasseur, JP., and Ayyangar, A., "A
Framework for Inter-Domain Multiprotocol Label
Switching Traffic Engineering", RFC 4726, November 2006.
[RFC4206] Kompella, K., and Rekhter, Y., "Label Switched Paths [RFC4206] Kompella, K., and Rekhter, Y., "Label Switched Paths
(LSP) Hierarchy with Generalized Multi-Protocol Label (LSP) Hierarchy with Generalized Multi-Protocol Label
Switching (GMPLS) Traffic Engineering (TE)," RFC4206, Switching (GMPLS) Traffic Engineering (TE)," RFC4206,
Oct. 2005. October 2005.
[RFC3945] E. Mannie (Editor), "Generalized Multi-Protocol Label
Switching (GMPLS) Architecture", RFC 3945, October 2004.
[RFC4397] Bryskin, I., and Farrel, A., "A Lexicography for the [RFC4397] Bryskin, I., and Farrel, A., "A Lexicography for the
Interpretation of Generalized Multiprotocol Label Interpretation of Generalized Multiprotocol Label
Switching (GMPLS) Terminology within the Context of the Switching (GMPLS) Terminology within the Context of the
ITU-T's Automatically Switched Optical Network (ASON) ITU-T's Automatically Switched Optical Network (ASON)
Architecture", RFC 4397, February 2006. Architecture", RFC 4397, February 2006.
[RFC4726] Farrel, A., Vasseur, JP., and Ayyangar, A., "A
Framework for Inter-Domain Multiprotocol Label
Switching Traffic Engineering", RFC 4726, November 2006.
9.2. Informative References 9.2. Informative References
[MRN-EVAL] Le Roux, J.L., Brungard, D., Oki, E., Papadimitriou, [DYN-HIER] Shiomoto, K., Rabbat, R., Ayyangar, A., Farrel, A. and
D., Shiomoto, K., Vigoureux, M., "Evaluation of Ali, Z., "Procedures for Dynamically Signaled
Existing GMPLS Protocols Against Multi-Layer and Hierarchical Label Switched Paths",
Multi-Region Network (MLN/MRN) Requirements", draft- draft-ietf-ccamp-lsp-hierarchy-bis, work in progress.
ietf-ccamp-gmpls- mln-eval, work in progress.
[MRN-EVAL] Le Roux, J.L., Brungard, D., Oki, E., Papadimitriou, D.,
Shiomoto, K., Vigoureux, M., "Evaluation of Existing
GMPLS Protocols Against Multi-Layer and Multi-Region
Network (MLN/MRN) Requirements",
draft-ietf-ccamp-gmpls-mln-eval, work in progress.
draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
[MPLS-GMPLS] K. Kumaki (Editor), "Interworking Requirements to [MPLS-GMPLS] K. Kumaki (Editor), "Interworking Requirements to
Support Operation of MPLS-TE over GMPLS Networks", Support Operation of MPLS-TE over GMPLS Networks",
draft-ietf-ccamp-mpls-gmpls-interwork-reqts, work in draft-ietf-ccamp-mpls-gmpls-interwork-reqts, work in
progress. progress.
[DYN-HIER] Shiomoto, K., Rabbat, R., Ayyangar, A., Farrel, A.
and Ali, Z., "Procedures for Dynamically Signaled
Hierarchical Label Switched Paths", draft-ietf-ccamp-
lsp-hierarchy-bis, work in progress.
[MPLS-SEC] Fang, L., et al., " Security Framework for MPLS and [MPLS-SEC] Fang, L., et al., " Security Framework for MPLS and
GMPLS Networks", draft-fang-mpls-gmpls-security- GMPLS Networks",
framework, work in progress. draft-ietf-mpls-mpls-and-gmpls-security-framework, work in
progress.
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007 [RFC4847] T. Takeda (Editor), " Framework and Requirements for Layer
1 Virtual Private Networks", RFC 4847, April 2007.
[RFC4972] Vasseur, JP., Le Roux, JL., et al., "Routing [RFC4972] Vasseur, JP., Le Roux, JL., et al., "Routing Extensions
Extensions for Discovery of Multiprotocol (MPLS) for Discovery of Multiprotocol (MPLS) Label Switch Router
Label Switch Router (LSR) Traffic Engineering (TE) (LSR) Traffic Engineering (TE) Mesh Membership", RFC 4972,
Mesh Membership", RFC 4972, July 2007. July 2007.
[RFC4847] T. Takeda (Editor), " Framework and Requirements for
Layer 1 Virtual Private Networks", RFC 4847, April
2007.
10. Authors' Addresses 10. Authors' Addresses
Kohei Shiomoto Kohei Shiomoto
NTT Network Service Systems Laboratories NTT Network Service Systems Laboratories
3-9-11 Midori-cho, Musashino-shi, Tokyo 180-8585, Japan 3-9-11 Midori-cho, Musashino-shi, Tokyo 180-8585, Japan
Email: shiomoto.kohei@lab.ntt.co.jp Email: shiomoto.kohei@lab.ntt.co.jp
Dimitri Papadimitriou Dimitri Papadimitriou
Alcatel-Lucent Alcatel-Lucent
Copernicuslaan 50, Copernicuslaan 50, B-2018 Antwerpen, Belgium
B-2018 Antwerpen, Belgium
Phone : +32 3 240 8491 Phone : +32 3 240 8491
Email: dimitri.papadimitriou@alcatel-lucent.be Email: dimitri.papadimitriou@alcatel-lucent.be
Jean-Louis Le Roux Jean-Louis Le Roux
France Telecom R&D, France Telecom R&D,
Av Pierre Marzin, Av Pierre Marzin, 22300 Lannion, France
22300 Lannion, France
Email: jeanlouis.leroux@orange-ft.com Email: jeanlouis.leroux@orange-ft.com
Martin Vigoureux Martin Vigoureux
Alcatel-Lucent Alcatel-Lucent
Route de Nozay, 91461 Marcoussis cedex, France Route de Nozay, 91461 Marcoussis cedex, France
Phone: +33 (0)1 69 63 18 52 Phone: +33 (0)1 69 63 18 52
Email: martin.vigoureux@alcatel-lucent.fr Email: martin.vigoureux@alcatel-lucent.fr
Deborah Brungard Deborah Brungard
AT&T AT&T
Rm. D1-3C22 - 200 Rm. D1-3C22 - 200
S. Laurel Ave., Middletown, NJ 07748, USA S. Laurel Ave., Middletown, NJ 07748, USA
Phone: +1 732 420 1573 Phone: +1 732 420 1573
Email: dbrungard@att.com Email: dbrungard@att.com
draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
11. Contributors' Addresses 11. Contributors' Addresses
Eiji Oki Eiji Oki
NTT Network Service Systems Laboratories NTT Network Service Systems Laboratories
3-9-11 Midori-cho, Musashino-shi, 3-9-11 Midori-cho, Musashino-shi,
Tokyo 180-8585, Tokyo 180-8585, Japan
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007
Japan
Phone: +81 422 59 3441 Phone: +81 422 59 3441
Email: oki.eiji@lab.ntt.co.jp Email: oki.eiji@lab.ntt.co.jp
Ichiro Inoue Ichiro Inoue
NTT Network Service Systems Laboratories NTT Network Service Systems Laboratories
3-9-11 Midori-cho, 3-9-11 Midori-cho,
Musashino-shi, Musashino-shi,
Tokyo 180-8585, Tokyo 180-8585, Japan
Japan
Phone: +81 422 59 3441 Phone: +81 422 59 3441
Email: ichiro.inoue@lab.ntt.co.jp Email: ichiro.inoue@lab.ntt.co.jp
Emmanuel Dotaro Emmanuel Dotaro
Alcatel-Lucent Alcatel-Lucent
Route de Nozay, Route de Nozay,
91461 Marcoussis cedex, 91461 Marcoussis cedex, France
France
Phone : +33 1 6963 4723 Phone : +33 1 6963 4723
Email: emmanuel.dotaro@alcatel-lucent.fr Email: emmanuel.dotaro@alcatel-lucent.fr
12. Intellectual Property Considerations 12. Intellectual Property Considerations
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed Intellectual Property Rights or other rights that might be claimed
to pertain to the implementation or use of the technology described to pertain to the implementation or use of the technology described
in this document or the extent to which any license under such in this document or the extent to which any license under such
rights might or might not be available; nor does it represent that rights might or might not be available; nor does it represent that
skipping to change at page 26, line 51 skipping to change at page 24, line 5
of such proprietary rights by implementers or users of this of such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository specification can be obtained from the IETF on-line IPR repository
at http://www.ietf.org/ipr. at http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at ietf- this standard. Please address the information to the IETF at ietf-
ipr@ietf.org. ipr@ietf.org.
draft-ietf-ccamp-gmpls-mln-reqs-07.txt November 2007
13. Full Copyright Statement 13. Full Copyright Statement
draft-ietf-ccamp-gmpls-mln-reqs-06.txt October 2007
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2007).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
This document and the information contained herein are provided on This document and the information contained herein are provided on
an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE
IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL
WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY
WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE
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