draft-ietf-ccamp-gmpls-mln-reqs-03.txt   draft-ietf-ccamp-gmpls-mln-reqs-04.txt 
Network Working Group Kohei Shiomoto (NTT) Network Working Group Kohei Shiomoto (NTT)
Internet-Draft Dimitri Papadimitriou (Alcatel) 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) Martin Vigoureux (Alcatel-Lucent)
Deborah Brungard (AT&T) Deborah Brungard (AT&T)
Expires: February 2008 August 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-03.txt draft-ietf-ccamp-gmpls-mln-reqs-04.txt
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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
have been related to environments hosting devices with a single related to environments hosting devices with a single switching capability. The
switching capability. The complexity raised by the control of such complexity raised by the control of such data planes is similar to that seen in
data planes is similar to that seen in classical IP/MPLS networks. classical IP/MPLS networks.
By extending MPLS to support multiple switching technologies, GMPLS By extending MPLS to support multiple switching technologies, GMPLS provides a
provides a comprehensive framework for the control of a multi- comprehensive framework for the control of a multi-layered network of either a
layered network of either a single switching technology or multiple single switching technology or multiple switching technologies.
switching technologies.
In GMPLS, a switching technology domain defines a region, and a draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
network of multiple switching types is referred to in this document
as a Multi-Region Network (MRN). When referring in general to a In GMPLS, a switching technology domain defines a region, and a network of
layered network, which may consist of either a single or multiple multiple switching types is referred to in this document as a Multi-Region
regions, this document uses the term, Multi-Layer Network (MLN). Network (MRN). When referring in general to a layered network, which may consist
This document defines a framework for GMPLS based multi- of either a single or multiple regions, this document uses the term, Multi-Layer
region/multi-layer networks and lists a set of functional Network (MLN). This document defines a framework for GMPLS based multi-
requirements. region/multi-layer networks and lists a set of functional requirements.
Table of Contents Table of Contents
1. Introduction...................................................3 1. Introduction.....................................................2
2. Conventions Used in this Document..............................4 2. Conventions Used in this Document....................................4
2.1. List of acronyms.............................................4 2.1. List of acronyms................................................4
3. Positioning....................................................5 3. Positioning......................................................5
3.1. Data Plane Layers and Control Plane Regions..................5 3.1. Data Plane Layers and Control Plane Regions..........................5
3.2. Service layer networks.......................................6 3.2. Service layer networks...........................................6
3.3. Vertical and Horizontal interaction and integration..........6 3.3. Vertical and Horizontal interaction and integration...................6
4. Key Concepts of GMPLS-Based MLNs and MRNs......................7 4. Key Concepts of GMPLS-Based MLNs and MRNs.............................8
4.1. Interface Switching Capability...............................7 4.1. Interface Switching Capability....................................8
4.2. Multiple Interface Switching Capabilities....................8 4.2. Multiple Interface Switching Capabilities...........................8
4.2.1. Networks with Multi-Switching-Type-Capable Hybrid Nodes....9 4.2.1. Networks with Multi-Switching-Type-Capable Hybrid Nodes..............9
4.3. Integrated Traffic Engineering (TE) and Resource Control.....9 4.3. Integrated Traffic Engineering (TE) and Resource Control..............10
4.3.1. Triggered Signaling.......................................10 4.3.1. Triggered Signaling...........................................10
4.3.2. FA-LSPs...................................................10 4.3.2. FA-LSPs.....................................................11
4.3.3. Virtual Network Topology (VNT)............................11 4.3.3. Virtual Network Topology (VNT)..................................11
5. Requirements..................................................12 5. Requirements....................................................12
5.1. Handling Single-Switching and Multi-Switching-Type-Capable 5.1. Handling Single-Switching and Multi-Switching-Type-Capable Nodes.......12
Nodes............................................................12 5.2. Advertisement of the Available Adaptation Resource...................12
5.2. Advertisement of the Available Adaptation Resource..........13 5.3. Scalability...................................................13
5.3. Scalability.................................................13 5.4. Stability.....................................................13
5.4. Stability...................................................13 5.5. Disruption Minimization.........................................14
5.5. Disruption Minimization.....................................14 5.6. LSP Attribute Inheritance........................................14
5.6. LSP Attribute Inheritance...................................14 5.7. Computing Paths With and Without Nested Signaling....................15
5.7. Computing Paths With and Without Nested Signaling...........15 5.8. LSP Resource Utilization........................................15
5.8. LSP Resource Utilization....................................16 5.8.1. FA-LSP Release and Setup.......................................16
5.8.1. FA-LSP Release and Setup..................................16 5.8.2. Virtual TE-Links.............................................16
5.8.2. Virtual TE-Links..........................................17 5.9. Verification of the LSPs........................................17
5.9. Verification of the LSPs....................................18 6. Security Considerations...........................................18
6. Security Considerations.......................................18 7. IANA Considerations..............................................18
7. IANA Considerations...........................................19 8. References......................................................18
8. References....................................................19 8.1. Normative Reference.............................................18
8.1. Normative Reference.........................................19 8.2. Informative References..........................................18
8.2. Informative References......................................19 9. Authors' Addresses...............................................19
9. Authors' Addresses............................................20 10. Contributors' Addresses..........................................20
10. Contributors' Addresses......................................21 11. Intellectual Property Considerations...............................20
11. Intellectual Property Considerations.........................21 12. Full Copyright Statement.........................................20
12. Full Copyright Statement.....................................22
1. Introduction
Generalized MPLS (GMPLS) extends MPLS to handle multiple switching 1. Introduction
technologies: packet switching, layer-2 switching, TDM switching,
wavelength switching, and fiber switching (see [RFC3945]). The
Interface Switching Capability (ISC) concept is introduced for
these switching technologies and is designated as follows: PSC
(packet switch capable), L2SC (Layer-2 switch capable), TDM (Time
Division Multiplex capable), LSC (lambda switch capable), and FSC
(fiber switch capable).
Service providers may operate networks where multiple different Generalized MPLS (GMPLS) extends MPLS to handle multiple switching technologies:
switching technologies exist. The representation, in a GMPLS packet switching, layer-2 switching, TDM switching, wavelength switching, and
control plane, of a switching technology domain is referred to as a fiber switching (see [RFC3945]). The Interface Switching Capability (ISC)
region [RFC4206]. draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
A switching type describes the ability of a node to forward data of concept is introduced for these switching technologies and is designated as
a particular data plane technology, and uniquely identifies a follows: PSC (packet switch capable), L2SC (Layer-2 switch capable), TDM (Time
network region. A layer describes a data plane switching Division Multiplex capable), LSC (lambda switch capable), and FSC (fiber switch
granularity level (e.g., VC4, VC-12). A data plane layer is capable).
associated with a region in the control plane (e.g., VC4 is
associated with TDM, MPLS is associated with PSC). However, more
than one data plane layer can be associated with the same region
(e.g., both VC4 and VC12 are associated with TDM). Thus, a control
plane region, identified by its switching type value (e.g., TDM),
can be sub-divided into smaller granularity component networks
based on "data plane switching layers". The Interface Switching
Capability Descriptor (ISCD) [RFC4202], identifying the interface
switching capability (ISC), the encoding type, and the switching
bandwidth granularity, enables the characterization of the
associated layers.
A network comprising nodes with multiple data plane layers of The representation, in a GMPLS control plane, of a switching technology domain
either the same ISC or different ISCs, controlled by a single GMPLS is referred to as a region [RFC4206]. A switching type describes the ability of
control plane instance is called a Multi-Layer Network (MLN). To a node to forward data of a particular data plane technology, and uniquely
differentiate a network supporting LSPs of different switching identifies a network region. A layer describes a data plane switching
types from a single region network, a network supporting more than granularity level (e.g., VC4, VC-12). A data plane layer is associated with a
one switching technology and controlled by a single GMPLS control region in the control plane (e.g., VC4 is associated with TDM, MPLS is
plane instance is called a Multi-Region Network (MRN). associated with PSC). However, more than one data plane layer can be associated
with the same region (e.g., both VC4 and VC12 are associated with TDM). Thus, a
control plane region, identified by its switching type value (e.g., TDM), can be
sub-divided into smaller granularity component networks based on "data plane
switching layers". The Interface Switching Capability Descriptor (ISCD)
[RFC4202], identifying the interface switching capability (ISC), the encoding
type, and the switching bandwidth granularity, enables the characterization of
the associated layers.
MLNs can be categorized according to the distribution of the ISCs In this document, we define a Multi Layer Network (MLN) to be a TE domain
among the LSRs: comprising multiple data plane switching layers either of the same ISC (e.g.
- Each LSR may support just one ISC. Such LSRs are known as TDM) or different ISC (e.g. TDM and PSC) and controlled by a single GMPLS
single-switching-type-capable LSRs. The MLN may comprise a set of control plane instance. We further define a particular case of MLNs. A Multi
single-switching-type-capable LSRs that support different ISCs. Region Network (MRN) is defined as a TE domain supporting at least two different
switching technologies (e.g. PSC + TDM) hosted on the same device (referred to
as multi-switching-type-capable LSRs, see below) and under the control of a
single GMPLS control plane instance.
MLNs can be further categorized according to the distribution of the ISCs among
the LSRs:
- Each LSR may support just one ISC.
Such LSRs are known as single-switching-type-capable LSRs.
The MLN may comprise a set of single-switching-type-capable LSRs
that 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 Such LSRs are known as multi-switching-type-capable LSRs, and
can be further classified as either "simplex" or "hybrid" nodes can be further classified as either ‘‘simplex’’ or hybrid’’ nodes
as defined in Section 4.2. as defined in Section 4.2.
- The MLN may be constructed from any combination of single- - The MLN may be constructed from any combination of single-switching-type-
switching-type-capable LSRs and multi-switching-type-capable capable LSRs and multi-switching-type-capable LSRs.
LSRs.
Since GMPLS provides a comprehensive framework for the control of Since GMPLS provides a comprehensive framework for the control of different
different switching capabilities, a single GMPLS instance may be switching capabilities, a single GMPLS instance controlling the MLN/MRN enables
used to control the MLN enabling rapid service provisioning and rapid service provisioning and efficient traffic engineering across all
efficient traffic engineering across all switching capabilities. In switching 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 the
Engineering Database (TED). Since this TED contains the information information relative to all the different regions and layers existing in the
relative to all the different regions and layers existing in the network, a path across multiple regions or layers can be computed using this TED.
network, a path across multiple regions or layers can be computed Thus optimization of network resources can be achieved across the whole MLN/MRN.
using this TED. Thus optimization of network resources can be
achieved across the whole MLN.
Consider, for example, a MRN consisting of packet-switch capable draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
routers and TDM cross-connects. Assume that a packet LSP is routed
between source and destination packet-switch capable routers, and
that the LSP can be routed across the PSC-region (i.e., utilizing
only resources of the packet region topology). If the performance
objective for the LSP is not satisfied, new TE links may be created
between the packet-switch capable routers across the TDM-region
(for example, VC-12 links) and the LSP can be routed over those TE
links. Further, even if the LSP can be successfully established
across the PSC-region, TDM hierarchical LSPs across the TDM region
between the packet-switch capable routers may be established and
used if doing so is necessary to meet the operator's objectives for
network resources availability (e.g., link bandwidth, or adaptation
ports between regions) across the regions. The same considerations
hold when VC4 LSPs are provisioned to provide extra flexibility for
the VC12 and/or VC11 layers in an MLN.
This document describes the requirements to support multi- Consider, for example, a MRN consisting of packet-switch capable routers and TDM
region/multi-layer networks. There is no intention to specify cross-connects. Assume that a packet LSP is routed between source and
solution-specific elements in this document. The applicability of destination packet-switch capable routers, and that the LSP can be routed across
existing GMPLS protocols and any protocol extensions to the MRN/MLN the PSC-region (i.e., utilizing only resources of the packet region topology).
is addressed in separate documents [MRN-EVAL]. If the performance objective for the packet LSP is not satisfied, new TE links
may be created between the packet-switch capable routers across the TDM-region
(for example, VC-12 links) and the LSP can be routed over those TE links.
Further, even if the LSP can be successfully established across the PSC-region,
TDM hierarchical LSPs across the TDM region between the packet-switch capable
routers may be established and used if doing so is necessary to meet the
operator's objectives for network resources availability (e.g., link bandwidth,
or adaptation ports between regions) across the regions. The same considerations
hold when VC4 LSPs are provisioned to provide extra flexibility for the VC12
and/or VC11 layers in an MLN.
1.1 Scope
This document describes the requirements to support multi-region/multi-layer
networks. There is no intention to specify solution-specific and/or protocol
elements in this document. The applicability of existing GMPLS protocols and any
protocol extensions to the MRN/MLN is addressed in separate documents [MRN-EVAL].
This document covers the elements of a single GMPLS control plane instance
controlling multiple layers within a given TE domain. A control plane instance
can serve one, two or more layers. Other possible approaches such as having
multiple control plane instances serving disjoint sets of layers are outside the
scope of this document.
For such TE domain to interoperate with edge nodes/domains supporting interfaces
by other SDOs e.g. ITU-T and OIF, an interworking function may be needed.
Location and specification of 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 TE domains
makes use of [RFC4726] when their edges also support inter-domain GMPLS RSVP-TE
extensions.
2. Conventions Used in this Document 2. Conventions Used in this Document
Although this is not a protocol specifcation, the key words "MUST", Although this is not a protocol specification, the key words "MUST", "MUST NOT",
"MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are used in this and "OPTIONAL" are used in this document to highlight requirements, and are to
document to highlight requirements, and are to be interpreted as be interpreted as described in RFC 2119 [RFC2119].
described in RFC 2119 [RFC2119].
2.1.List of acronyms 2.1.List of acronyms
MLN: Multi-Layer Network MLN: Multi-Layer Network
MRN: Multi-Region Network MRN: Multi-Region Network
draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
ISC: Interface Switching Capability ISC: Interface Switching Capability
ISCD: Interface Switching Capability Descriptor ISCD: Interface Switching Capability Descriptor
PSC: Packet Switching Capable PSC: Packet Switching Capable
L2SC: Layer-2 Switching Capable L2SC: Layer-2 Switching Capable
TDM: Time-Division Switch Capable TDM: Time-Division Switch Capable
LSC: Lambda Switching Capable LSC: Lambda Switching Capable
FSC: Fiber Switching Capable FSC: Fiber Switching Capable
SRLG: Shared Risk Ling Group SRLG: Shared Risk Ling Group
VNT: Virtual Network Topology VNT: Virtual Network Topology
FA: Forwarding Adjacency FA: Forwarding Adjacency
FA-LSP: Forwarding Adjacency Label Switched Path FA-LSP: Forwarding Adjacency Label Switched Path
TE: Traffic Engineering TE: Traffic Engineering
TED: Traffic Engineering Database TED: Traffic Engineering Database
LSP: Label Switched Path LSP: Label Switched Path
LSR: Label Switching Router LSR: Label Switching Router
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
since the network devices on region boundaries bring together network devices on region boundaries bring together different ISCs. A MLN,
different ISCs. A MLN, however, is not necessarily a MRN since however, is not necessarily a MRN since multiple layers could be fully contained
multiple layers could be fully contained within a single region. within a single region. For example, VC12, VC4, and VC4-4c are different layers
For example, VC12, VC4, and VC4-4c are different layers of the TDM of the TDM region.
region.
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
terminating and/or switching data traffic of a particular and/or switching data traffic of a particular format [RFC4397]. These resources
format[RFC4397]. These resources can be used for establishing LSPs can be used for establishing LSPs for traffic delivery. For example, VC-11 and
for traffic delivery. For example, VC-11 and VC4-64c represent two 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
of one or more data plane layers that share the same type of more data plane layers that share the same type of switching technology, that is,
switching technology, that is, the same switching type. For example, the same switching type. For example, VC-11, VC-4, and VC-4-7v layers are part
VC-11 and VC-4 layers are part of the same TDM region. The regions of the same TDM region. The regions that are currently defined are: PSC, L2SC,
that are currently defined are: PSC, L2SC, TDM, LSC, and FSC. Hence, TDM, LSC, and FSC. Hence, an LSP region is a technology domain (identified by
an LSP region is a technology domain (identified by the ISC type) the ISC type) for which data plane resources (i.e., data links) are represented
for which data plane resources (i.e., data links) are represented into the control plane as an aggregate of TE information associated with a set
into the control plane as an aggregate of TE information associated of links (i.e., TE links). For example VC-11 and VC4-64c capable TE links are
with a set of links (i.e., TE links). For example VC-11 and VC4-64c part of the same TDM region. Multiple layers can thus exist in a single region
capable TE links are part of the same TDM region. Multiple layers network.
can thus exist in a single region network.
Note also that the region may produce a distinction within the control plane.
Layers of the same region share the same switching technology and, therefore,
use the same set of technology-specific signaling objects and technology-
specific value setting of TE link attributes within the control plane, but
layers from different regions may use different technology-specific objects and
TE attribute values. This means that it may not be possible to simply forward
the signaling message between LSR hosting different switching technologies
because change in some of the signaling objects (for example, the traffic
draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
parameters) when crossing a region boundary even if a single control plane
instance is used to manage the whole MRN. We may solve the issue by using
triggered signaling (See 4.3.1).
Note also that the region may produce a distinction within the
control plane. Layers of the same region share the same switching
technology and, therefore, use the same set of technology-specific
signaling objects within the control plane, but layers from
different regions may use different technology-specific objects or
encodings. This means that there is a control plane discontinuity
when crossing a region boundary even if a single control plane
instance is used to manage the whole MRN.
3.2. Service layer networks 3.2. Service layer networks
A service provider's network may be divided into different service A service provider's network may be divided into different service layers. The
layers. The customer's network is considered from the provider's customer's network is considered from the provider's perspective as the highest
perspective as the highest service layer. It interfaces to the service layer. It interfaces to the highest service layer of the service
highest service layer of the service provider's network. 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 lower service
provider's network may be provided with support from successively layers. Service layers are realized via a hierarchy of network layers located
lower service layers. Service layers are realized via a hierarchy generally in several regions and commonly arranged according to the switching
of network layers located generally in several regions and commonly capabilities of network devices.
arranged according to the switching capabilities of network devices.
For instance some customers purchase Layer 1 (i.e., transport) For instance some customers purchase Layer 1 (i.e., transport) services from the
services from the service provider, some Layer 2 (e.g., ATM), while service provider, some Layer 2 (e.g., ATM), while others purchase Layer 3
others purchase Layer 3 (IP/MPLS) services. The service provider (IP/MPLS) services. The service provider realizes the services by a stack of
realizes the services by a stack of network layers located within network layers located within one or more network regions. The network layers
one or more network regions. The network layers are commonly are commonly arranged according to the switching capabilities of the devices in
arranged according to the switching capabilities of the devices in the networks. Thus, a customer network may be provided on top of the GMPLS-based
the networks. Thus, a customer network may be provided on top of multi-region/multi-layer network. For example, a Layer 1 service (realized via
the GMPLS-based multi-region/multi-layer network. For example, a the network layers of TDM, and/or LSC, and/or FSC regions) may support a Layer 2
Layer 1 service (realized via the network layers of TDM, and/or LSC, network (realized via ATM VP/VC) which may itself support a Layer 3 network
and/or FSC regions) may support a Layer 2 network (realized via ATM (IP/MPLS region). The supported data plane relationship is a data plane client-
VP/VC) which may itself support a Layer 3 network (IP/MPLS region). server relationship where the lower layer provides a service for the higher
The supported data plane relationship is a data plane client-server layer using the data links realized in the lower layer.
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
are referred to as "Multi-region/Multi-layer network services". For to as "Multi-region/Multi-layer network services". For example, legacy IP and
example, legacy IP and IP/MPLS networks can be supported on top of IP/MPLS networks can be supported on top of multi-region/multi-layer networks.
multi-region/multi-layer networks. It has to be emphasized that It has to be emphasized that delivery of such diverse services is a strong
delivery of such diverse services is a strong motivator for the 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
MRN/MLN which is operated by a service provider. For example, a is operated by a service provider. For example, a pure IP and/or an IP/MPLS
pure IP and/or an IP/MPLS network can be provided on top of GMPLS- network can be provided on top of GMPLS-based packet over optical networks
based packet over optical networks [MPLS-GMPLS]. The relationship [MPLS-GMPLS]. The relationship between the networks is a client/server
between the networks is a client/server relationship and, such relationship and, such services are referred to as "MRN/MLN services". In this
services are referred to as "MRN/MLN services". In this case, the case, the customer network may form part of the MRN/MLN, or may be partially
customer network may form part of the MRN/MLN, or may be partially separated, for example to maintain separate routing information but retain
separated, for example to maintain separate routing information but common signaling.
retain common 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
within a network element that is capable of supporting more than
one layer and of realizing the client/server relationships between
the layers. Protocol exchanges between two network controllers
managing different regions or layers are also a vertical
interaction. Integration of these interactions as part of the
control plane is referred to as vertical integration. Thus, this
refers to the collaborative mechanisms within a single control
plane instance driving multiple network layers. Such a concept is
useful in order to construct a framework that facilitates efficient
network resource usage and rapid service provisioning in carrier
networks that are based on multiple layers, switching technologies,
or ISCs.
Horizontal interaction is defined as the protocol exchange between Vertical interaction is defined as the collaborative mechanisms within a network
network controllers that manage transport nodes within a given element that is capable of supporting more than one layer or region and of
layer or region (i.e., nodes with the same switching capability). realizing the client/server relationships between the layers or regions.
For instance, the control plane interaction between two TDM network Protocol exchanges between two network controllers managing different regions or
elements switching at OC-48 is an example of horizontal interaction. layers are also a vertical interaction. Integration of these interactions as
GMPLS protocol operations handle horizontal interactions within the part of the control plane is referred to as vertical integration. Thus, this
same routing area. The case where the interaction takes place draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
across a domain boundary, such as between two routing areas within
the same network layer, is evaluated as part of the inter-domain
work [RFC4726], and is referred to as horizontal integration. Thus,
horizontal integration refers to the collaborative mechanisms
between network partitions and/or administrative divisions such as
routing areas or autonomous systems.
This distinction needs further clarification when administrative refers to the collaborative mechanisms within a single control plane instance
domains match layer boundaries. Horizontal interaction is extended driving multiple network layers part of the same region or not. Such a concept
to cover such cases. For example, the collaborative mechanisms in is useful in order to construct a framework that facilitates efficient network
place between two lambda switching capable areas relate to resource usage and rapid service provisioning in carrier networks that are based
horizontal integration. On the other hand, the collaborative on multiple layers, switching technologies, or ISCs.
mechanisms in place in a network that supports IP/MPLS over TDM
switching could be described as vertical and horizontal integration Horizontal interaction is defined as the protocol exchange between network
in the case where each network belongs to a separate routing area. controllers that manage transport nodes within a given layer or region. For
instance, the control plane interaction between two TDM network elements
switching at OC-48 is an example of horizontal interaction. GMPLS protocol
operations handle horizontal interactions within the same routing area. The case
where the interaction takes place across a domain boundary, such as between two
routing areas within the same network layer, is evaluated as part of the inter-
domain work [RFC4726], and is referred to as horizontal integration. Thus,
horizontal integration refers to the collaborative mechanisms between network
partitions and/or administrative divisions such as routing areas or autonomous
systems.
This distinction needs further clarification when administrative domains match
layer/region boundaries. Horizontal interaction is extended to cover such cases.
For example, the collaborative mechanisms in place between two lambda switching
capable areas relate to horizontal integration. On the other hand, the
collaborative mechanisms in place between a packet switching capable (e.g.
IP/MPLS) domain over a different time division switching capable (eg VC4 SDH)
domain is part of the horizontal integration while it can be seen as a first
step towards vertical integration.
3.4.Motivation
The applicability of GMPLS to multiple switching technologies provides the
unified control management approach for both LSP provisioning and recovery.
Indeed, one of the main motivations for unifying the capabilities and operations
GMPLS control plane is the desire to support multi LSP-region [RFC4206] routing
and Traffic Engineering (TE) capability. For instance, this enables effective
network resource utilization of both the Packet/Layer2 LSP regions and the Time
Division Multiplexing (TDM) or Lambda LSP regions in high capacity networks.
The rationales for GMPLS controlled multi-layer/multi-region networks context
are summarized here below:
- The maintenance of multiple instances of the control plane on devices hosting
more than one switching capability not only increases the complexity of their
interactions but also increases the total amount of processing individual
instances would handle.
- The unification of the addressing spaces helps in avoiding multiple
identification for the same object (a link for instance or more generally any
network resource), on the other hand such aggregation does not impact the
separation between the control and the data plane.
- By maintaining a single routing protocol instance and a single TE database
per LSR, a unified control plane model prevents from maintaining a dedicated
routing topology per layer and therefore does not mandate a full mesh of
routing adjacencies as it is the case with overlaid control planes.
draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
- The collaboration between associated control planes (packet/framed data
planes) and non-associated control planes (SONET/SDH, G.709, etc.) is
facilitated due to the capability of hooking the associated in-band signaling
to the IP terminating interfaces of the control plane.
- Resource management and policies to be applied at the edges of such
environment is facilitated (less control to management interactions) and more
scalable (through the use of aggregated information).
- Multi-region/multi-layer traffic engineering is facilitated as TE-links from
distinct regions/layers are stored within the same TE Database.
4. Key Concepts of GMPLS-Based MLNs and MRNs 4. Key Concepts of GMPLS-Based MLNs and MRNs
A network comprising transport nodes with multiple data plane A network comprising transport nodes with multiple data plane layers of either
layers of either the same ISC or different ISCs, controlled by a the same ISC or different ISCs, controlled by a single GMPLS control plane
single GMPLS control plane instance, is called a Multi-Layer instance, is called a Multi-Layer Network (MLN). A sub-set of MLNs consists of
Network (MLN). A sub-set of MLNs consists of networks supporting networks supporting LSPs of different switching technologies (ISCs). A network
LSPs of different switching technologies (ISCs). A network supporting more than one switching technology is called a Multi-Region Network
supporting more than one switching technology is called a Multi- (MRN).
Region Network (MRN).
4.1. Interface Switching Capability 4.1. Interface Switching Capability
The Interface Switching Capability (ISC) is introduced in GMPLS to
support various kinds of switching technology in a unified way
[RFC4202]. An ISC is identified via a switching type.
A switching type (also referred to as the switching capability The Interface Switching Capability (ISC) is introduced in GMPLS to support
type) describes the ability of a node to forward data of a various kinds of switching technology in a unified way [RFC4202]. An ISC is
particular data plane technology, and uniquely identifies a network identified via a switching type.
region. The following ISC types (and, hence, regions) are defined:
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
GMPLS network is associated with an ISC.
The ISC value is advertised as a part of the Interface Switching A switching type (also referred to as the switching capability type) describes
Capability Descriptor (ISCD) attribute (sub-TLV) of a TE link end the ability of a node to forward data of a particular data plane technology, and
associated with a particular link interface [RFC4202]. Apart from uniquely identifies a network region. The following ISC types (and, hence,
the ISC, the ISCD contains information including the encoding type, regions) are defined: PSC, L2SC, TDM, LSC, and FSC. Each end of a data link
the bandwidth granularity, and the unreserved bandwidth on each of (more precisely, each interface connecting a data link to a node) in a GMPLS
eight priorities at which LSPs can be established. The ISCD does network is associated with an ISC.
not "identify" network layers, it uniquely characterizes
information associated to one or more network layers.
TE link end advertisements may contain multiple ISCDs. This can be The ISC value is advertised as a part of the Interface Switching Capability
interpreted as advertising a multi-layer (or multi-switching- Descriptor (ISCD) attribute (sub-TLV) of a TE link end associated with a
capable) TE link end. That is, the TE link end (and therefore the particular link interface [RFC4202]. Apart from the ISC, the ISCD contains
TE link) is present in multiple layers. information including the encoding type, the bandwidth granularity, and the
unreserved bandwidth on each of eight priorities at which LSPs can be
established. The ISCD does not "identify" network layers, it uniquely
characterizes information associated to one or more network layers.
TE link end advertisements may contain multiple ISCDs. This can be interpreted
as advertising a multi-layer (or multi-switching-capable) TE link end. That is,
the TE link end (and therefore the 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-
multi-switching-type-capable nodes. Single-switching-type-capable switching-type-capable nodes. Single-switching-type-capable nodes advertise the
nodes advertise the same ISC value as part of their ISCD sub-TLV(s) same ISC value as part of their ISCD sub-TLV(s) to describe the termination
to describe the termination capabilities of each of their TE capabilities of each of their TE 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 draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
"hybrid" nodes. Simplex and hybrid nodes are categorized according
to the way they advertise these multiple ISCs:
- A simplex node can terminate data links with different switching Multi-switching-type-capable LSRs are classified as "simplex" or "hybrid" nodes.
capabilities where each data link is connected to the node by a Simplex and hybrid nodes are categorized according to the way they advertise
separate link interface. So, it advertises several TE Links each these multiple ISCs:
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 LSR
via a separate interface.
- A hybrid node can terminate data links with different switching - A simplex node can terminate data links with different switching capabilities
capabilities where the data links are connected to the node by the where each data link is connected to the node by a separate link interface.
same interface. So, it advertises a single TE Link containing more So, it advertises several TE Links each with a single ISC value carried in
than one ISCD each with a different ISC value. For example, a node its ISCD sub-TLV. For example, an LSR with PSC and TDM links each of which is
may terminate PSC and TDM data links and interconnect those connected to the LSR via a separate interface.
external data links via internal links. The external interfaces
connected to the node have both PSC and TDM capabilities.
Additionally, TE link advertisements issued by a simplex or a - A hybrid node can terminate data links with different switching capabilities
hybrid node may need to provide information about the node's where the data links are connected to the node by the same interface. So, it
internal adaptation capabilities between the switching technologies advertises a single TE Link containing more than one ISCD each with a
supported. That is, the node's capability to perform layer border different ISC value. For example, a node may terminate PSC and TDM data links
node functions. and interconnect those external data links via internal links. The external
interfaces connected to the node have both PSC and TDM capabilities.
Additionally, TE link advertisements issued by a simplex or a hybrid node may
need to provide information about the node's internal adaptation capabilities
between the switching technologies supported. That is, the node's capability to
perform layer border node functions.
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 This type of network contains at least one hybrid node, zero or more simplex
more simplex nodes, and a set of single-switching-type-capable nodes, and a set of single-switching-type-capable nodes.
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
switching elements (matrices), which support, for instance, TDM and elements (matrices), which support, for instance, TDM and PSC switching
PSC switching respectively. The node terminates a PSC and a TDM respectively. The node terminates a PSC and a TDM link (Link1 and Link2
link (Link1 and Link2 respectively). It also has an internal link respectively). It also has an internal link connecting the two switching
connecting the two switching elements. elements.
The two switching elements are internally interconnected in such a The two switching elements are internally interconnected in such a way that it
way that it is possible to terminate some of the resources of, say, is possible to terminate some of the resources of, say, Link2 and provide
Link2 and provide adaptation for PSC traffic received/sent over the adaptation for PSC traffic received/sent over the PSC interface (#b). This
PSC interface (#b). This situation is modeled in GMPLS by situation is modeled in GMPLS by connecting the local end of Link2 to the TDM
connecting the local end of Link2 to the TDM switching element via switching element via an additional interface realizing the
an additional interface realizing the termination/adaptation termination/adaptation function. There are two possible ways to set up PSC LSPs
function. There are two possible ways to set up PSC LSPs through through the hybrid node. Available resource advertisement (i.e., Unreserved and
the hybrid node. Available resource advertisement (i.e., Unreserved Min/Max LSP Bandwidth) should cover both of these methods.
and Min/Max LSP Bandwidth) should cover both of these methods.
Network element Network element
............................. .............................
: -------- : : -------- :
: | PSC | : : | PSC | :
Link1 -------------<->--|#a | : Link1 -------------<->--|#a | :
: +--<->---|#b | : : +--<->---|#b | :
: | -------- : : | -------- :
TDM : | ---------- : TDM : | ---------- :
+PSC : +--<->--|#c TDM | : +PSC : +--<->--|#c TDM | :
draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
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
consolidated into a single Traffic Engineering Database (TED) for
use by the single control plane instance. Since this TED contains
the information relative to all the layers of all regions in the
network, a path across multiple layers (possibly crossing multiple
regions) can be computed using the information in this TED. Thus,
optimization of network resources across the multiple layers of the
same region and across multiple regions can be achieved.
These concepts allow for the operation of one network layer over In GMPLS-based multi-region/multi-layer networks, TE Links may be consolidated
the topology (that is, TE links) provided by other network layers into a single Traffic Engineering Database (TED) for use by the single control
(for example, the use of a lower layer LSC LSP carrying PSC LSPs). plane instance. Since this TED contains the information relative to all the
In turn, a greater degree of control and inter-working can be layers of all regions in the network, a path across multiple layers (possibly
achieved, including (but not limited too): crossing multiple regions) can be computed using the information in this TED.
Thus, optimization of network resources across the multiple layers of the same
region and across multiple regions can be achieved.
These concepts allow for the operation of one network layer over the topology
(that is, TE links) provided by other network layers (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 achieved, including (but not limited too):
- Dynamic establishment of Forwarding Adjacency (FA) LSPs - Dynamic establishment of Forwarding Adjacency (FA) LSPs
[RFC4206] (see Sections 4.3.2 and 4.3.3). [RFC4206] (see Sections 4.3.2 and 4.3.3).
- Provisioning of end-to-end LSPs with dynamic triggering of FA - Provisioning of end-to-end LSPs with dynamic triggering of FA
LSPs. LSPs.
Note that in a multi-layer/multi-region network that includes Note that in a multi-layer/multi-region network that includes multi-switching-
multi-switching-type-capable nodes, an explicit route used to type-capable nodes, an explicit route used to establish an end-to-end LSP can
establish an end-to-end LSP can specify nodes that belong to specify nodes that belong to different layers or regions. In this case, a
different layers or regions. In this case, a mechanism to control mechanism to control the dynamic creation of FA LSPs may be required (see
the dynamic creation of FA LSPs may be required (see Sections 4.3.2 Sections 4.3.2 and 4.3.3).
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
dynamically established. The process can be subject to the control established. The process can be subject to the control of a policy, which may be
of a policy, which may be set by a management component, and which set by a management component, and which may require that the management plane
may require that the management plane is consulted at the time that is consulted at the time that the FA LSP is established. Alternatively, the FA
the FA LSP is established. Alternatively, the FA LSP can be LSP can be established at the request of the control plane without any
established 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
may be nested into a lower layer FA LSP that crosses the lower nested into a lower layer FA LSP that crosses the lower layer. From a signaling
layer. From a signaling perspective, there are two alternatives to perspective, there are two alternatives to establish the lower layer FA LSP:
establish the lower layer FA LSP: static (pre-provisioned) and static (pre-provisioned) and dynamic (triggered). A pre-provisioned FA-LSP may
dynamic (triggered). A pre-provisioned FA-LSP may be initiated be initiated either by the operator or automatically using features like TE
either by the operator or automatically using features like TE auto-mesh [AUTO-MESH]. If such a lower layer LSP does not already exist, the LSP
auto-mesh [AUTO-MESH]. If such a lower layer LSP does not already may be established dynamically. Such a mechanism is referred to as "triggered
exist, the LSP may be established dynamically. Such a mechanism is signaling".
referred to as "triggered signaling".
draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
4.3.2. FA-LSPs 4.3.2. FA-LSPs
Once an LSP is created across a layer from one layer border node to
another, it can be used as a data link in an upper layer.
Furthermore, it can be advertised as a TE-link, allowing other Once an LSP is created across a layer from one layer border node to another, it
nodes to consider the LSP as a TE link for their path computation can be used as a data link in an upper layer.
[RFC4206]. An LSP created either statically or dynamically by one
instance of the control plane and advertised as a TE link into the
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
link is called a Forwarding Adjacency (FA). An FA has the special
characteristic of not requiring a routing adjacency (peering)
between its end points yet still guaranteeing control plane
connectivity between the FA-LSP end points based on a signaling
adjacency. An FA is a useful and powerful tool for improving the
scalability of GMPLS Traffic Engineering (TE) capable networks
since multiple higher layer LSPs may be nested (aggregated) over a
single FA-LSP.
The aggregation of LSPs enables the creation of a vertical (nested) Furthermore, it can be advertised as a TE-link, allowing other nodes to consider
LSP Hierarchy. A set of FA-LSPs across or within a lower layer can the LSP as a TE link for their path computation [RFC4206]. An LSP created either
be used during path selection by a higher layer LSP. Likewise, the statically or dynamically by one instance of the control plane and advertised as
higher layer LSPs may be carried over dynamic data links realized a TE link into the same instance of the control plane is called a Forwarding
via LSPs (just as they are carried over any "regular" static data Adjacency LSP (FA-LSP). The FA-LSP is advertised as a TE link, and that TE link
links). This process requires the nesting of LSPs through a is called a Forwarding Adjacency (FA). An FA has the special characteristic of
hierarchical process [RFC4206]. The TED contains a set of LSP not requiring a routing adjacency (peering) between its end points yet still
advertisements from different layers that are identified by the guaranteeing control plane connectivity between the FA-LSP end points based on a
ISCD contained within the TE link advertisement associated with the signaling adjacency. An FA is a useful and powerful tool for improving the
LSP [RFC4202]. scalability of GMPLS Traffic Engineering (TE) capable networks since multiple
higher layer LSPs may be nested (aggregated) over a single FA-LSP.
If a lower layer LSP is not advertised as an FA, it can still be The aggregation of LSPs enables the creation of a vertical (nested) LSP
used to carry higher layer LSPs across the lower layer. For example, Hierarchy. A set of FA-LSPs across or within a lower layer can be used during
if the LSP is set up using triggered signaling, it will be used to path selection by a higher layer LSP. Likewise, the higher layer LSPs may be
carry the higher layer LSP that caused the trigger. Further, the carried over dynamic data links realized via LSPs (just as they are carried over
lower layer remains available for use by other higher layer LSPs any "regular" static data links). This process requires the nesting of LSPs
arriving at the boundary. through a hierarchical 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].
Under some circumstances it may be useful to control the If a lower layer LSP is not advertised as an FA, it can still be used to carry
advertisement of LSPs as FAs during the signaling establishment of higher layer LSPs across the lower layer. For example, if the LSP is set up
the LSPs [DYN-HIER]. using triggered signaling, it will be used to carry the higher layer LSP that
caused the trigger. Further, the lower layer remains available for use by other
higher layer LSPs arriving at the boundary.
Under some circumstances it may be useful to control the advertisement of LSPs
as FAs during the signaling establishment of 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
efficient path handling in upper-layer(s) of the MLN, or, in other handling in upper-layer(s) of the MLN, or, in other words, provides a virtual
words, provides a virtual network topology (VNT) to the upper- network topology (VNT) to the upper-layers. For instance, a set of LSPs, each of
layers. For instance, a set of LSPs, each of which is supported by which is supported by an LSC LSP, provides a virtual network topology to the
an LSC LSP, provides a virtual network topology to the layers of a layers of a PSC region, assuming that the PSC region is connected to the LSC
PSC region, assuming that the PSC region is connected to the LSC region. Note that a single lower-layer LSP is a special case of the VNT. The
region. Note that a single lower-layer LSP is a special case of the virtual network topology is configured by setting up or tearing down the lower
VNT. The virtual network topology is configured by setting up or layer LSPs. By using GMPLS signaling and routing protocols, the virtual network
tearing down the lower layer LSPs. By using GMPLS signaling and topology can be adapted to traffic demands.
routing protocols, the virtual network topology can be adapted to
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
diversely-routed lower-layer LSPs are used or not, the routes of lower-layer LSPs are used or not, the routes of lower-layer LSPs are hidden from
lower-layer LSPs are hidden from the upper layer in the VNT. Thus, the upper layer in the VNT. Thus, the VNT simplifies the upper-layer routing and
the VNT simplifies the upper-layer routing and traffic engineering draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
decisions by hiding the routes taken by the lower-layer LSPs.
However hiding the routes of the lower-layer LSPs may lose
important information that is needed to make the higher-layer LSPs
reliable. For instance, the routing and traffic engineering in the
IP/MPLS layer does not usually consider how the IP/MPLS TE links
are formed from optical paths that are routed in the fiber layer.
Two optical paths may share the same fiber link in the lower-layer
and therefore they may both fail if the fiber link is cut. Thus the
shared risk properties of the TE links in the VNT must be made
available to the higher layer during path computation. Further, the
topology of the VNT should be designed so that any single fiber cut
does not bisect the VNT. These issues are addressed later in this
document.
Reconfiguration of the virtual network topology may be triggered by traffic engineering decisions by hiding the routes taken by the lower-layer LSPs.
traffic demand changes, topology configuration changes, signaling However hiding the routes of the lower-layer LSPs may lose important information
requests from the upper layer, and network failures. For instance, that is needed to make the higher-layer LSPs reliable. For instance, the routing
by reconfiguring the virtual network topology according to the and traffic engineering in the IP/MPLS layer does not usually consider how the
traffic demand between source and destination node pairs, network IP/MPLS TE links are formed from optical paths that are routed in the fiber
performance factors, such as maximum link utilization and residual layer. Two optical paths may share the same fiber link in the lower-layer and
capacity of the network, can be optimized. Reconfiguration is therefore they may both fail if the fiber link is cut. Thus the shared risk
performed by computing the new VNT from the traffic demand matrix properties of the TE links in the VNT must be made available to the higher layer
and optionally from the current VNT. Exact details are outside the during path computation. Further, the topology of the VNT should be designed so
scope of this document. However, this method may be tailored that any single fiber cut does not bisect the VNT. These issues are addressed
according to the service provider's policy regarding network later in this document.
performance and quality of service (delay, loss/disruption,
utilization, residual capacity, reliability). Reconfiguration of the virtual network topology may be triggered by traffic
demand changes, topology configuration changes, signaling requests from the
upper layer, and network failures. For instance, by reconfiguring the virtual
network topology according to the traffic demand between source and destination
node pairs, network performance factors, such as maximum link utilization and
residual capacity of the network, can be optimized. Reconfiguration is performed
by computing the new VNT from the traffic demand matrix and optionally from the
current VNT. Exact details are outside the scope of this document. However, this
method may be tailored according to the service provider's policy regarding
network performance and quality of service (delay, loss/disruption, 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- The MRN/MLN can consist of single-switching-type-capable and multi-switching-
switching-type-capable nodes. The path computation mechanism in the type-capable nodes. The path computation mechanism in the MLN SHOULD be able to
MLN SHOULD be able to compute paths consisting of any combination compute paths consisting of any combination of such nodes.
of such nodes.
Both single-switching-type-capable and multi-switching-type-capable (simplex or
hybrid) nodes could play the role of layer boundary. MRN/MLN Path computation
SHOULD handle TE topologies built of any combination of nodes
Both single-switching-type-capable and multi-switching-type-capable
(simplex or hybrid) nodes could play the role of layer boundary.
MRN/MLN Path computation SHOULD handle TE topologies built of any
combination of nodes
5.2. Advertisement of the Available Adaptation Resource 5.2. Advertisement of the Available Adaptation Resource
A hybrid node SHOULD maintain resources on its internal links (the A hybrid node SHOULD maintain resources on its internal links (the links
links required for vertical (layer) integration) and SHOULD required for vertical (layer) integration) and SHOULD advertise the resource
advertise the resource information for those links. Likewise, path information for those links. Likewise, path computation elements SHOULD be
computation elements SHOULD be prepared to use the availability of prepared to use the availability of termination/adaptation resources as a
termination/adaptation resources as a constraint in MRN/MLN path constraint in MRN/MLN path computations to reduce the higher layer LSP setup
computations to reduce the higher layer LSP setup blocking blocking probability caused by the lack of necessary termination/ adaptation
probability caused by the lack of necessary termination/ adaptation
resources in the lower layer(s). resources in the lower layer(s).
The advertisement of the adaptation capability to terminate LSPs of The advertisement of the adaptation capability to terminate LSPs of lower-region
lower-region and forward traffic in the upper-region is REQUIRED, and forward traffic in the upper-region is REQUIRED, as it provides critical
as it provides critical information when performing multi-region information when performing multi-region path computation.
path computation.
The mechanism SHOULD cover the case where the upper-layer links draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
which are directly connected to upper-layer switching element and
the ones which are connected through internal links between upper- The mechanism SHOULD cover the case where the upper-layer links which are
layer element and lower-layer element coexist (See section 4.2.1). directly connected to upper-layer switching element and the ones which are
connected through internal links between upper-layer element and lower-layer
element coexist (See section 4.2.1).
5.3. Scalability 5.3. Scalability
The MRN/MLN relies on a unified traffic engineering and routing The MRN/MLN relies on a unified traffic engineering and routing model.
model. The TED in each LSR is populated with TE-links from all - Unified routing model: by maintaining a single routing protocol instance and
layers of all regions. This may lead to a huge amount of a single TE database per LSR, a unified control plane model prevents from
maintaining a dedicated routing topology per layer and therefore does not
mandate a full mesh of routing adjacencies per layer.
- Unified TE model: the TED in each LSR is populated with TE-links from all
layers of all regions (TE links interfaces on multiple-switching capability
LSR can be advertised with multiple ISCD). This may lead to a large amount of
information that has to be flooded and stored within the network. information that has to be flooded and stored within the network.
Furthermore, path computation times, which may be of great
importance during restoration, will depend on the size of the TED.
Thus MRN/MLN routing mechanisms MUST be designed to scale well with Furthermore, path computation times, which may be of great importance during
an increase of any of the following: restoration, will depend on the size of the TED.
Thus MRN/MLN routing mechanisms MUST be designed to scale well with 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 LSPs
- Number of regions and layers - 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
information filtering based on ISCDs. The path computation filtering based on ISCDs. The path computation mechanism and the signaling
mechanism and the signaling protocol SHOULD be able to operate on protocol SHOULD be able to operate on partial TE information.
partial TE information.
Since TE Links can advertise multiple Interface Switching Capabilities (ISC),
the number of links can be limited (by combination) by using specific
topological maps referred to as VNT (Virtual Network Topologies). The
introduction of virtual topological maps leads us to consider the concept of
emulation of data plane 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 link state.
associated link state. The path computation stability of an upper The path computation stability of an upper layer may be impaired if the VNT
layer may be impaired if the VNT changes frequently and/or if the changes frequently and/or if the status and TE parameters (the TE metric, for
status and TE parameters (the TE metric, for instance) of links in instance) of links in the VNT changes frequently. In this context, robustness of
the VNT changes frequently. the VNT is defined as the 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.
In this context, robustness of the VNT is defined as the capability Creation, deletion, and modification of LSPs MAY be triggered by adjacent layers
to smooth changes that may occur and avoid their propagation into or through operational actions to meet traffic demand changes, topology changes,
higher layers. Changes to the VNT may be caused by the creation, signaling requests from the upper layer, and network failures. Routing
deletion, or modification of LSPs. draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
Creation, deletion, and modification of LSPs MAY be triggered by robustness SHOULD be traded with adaptability with respect to the change of
adjacent layers or through operational actions to meet traffic incoming traffic requests.
demand changes, topology changes, signaling requests from the upper
layer, and network failures. Routing robustness SHOULD be traded
with adaptability with respect to the change of incoming traffic
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-
the upper-layer LSP might be disrupted. Such disruption to the layer LSP might be disrupted. Such disruption to the upper layers MUST be
upper layers MUST be minimized. minimized.
When residual resource decreases to a certain level, some lower When residual resource decreases to a certain level, some lower layer LSPs MAY
layer LSPs MAY be released according to local or network policies. be released according to local or network policies. There is a trade-off between
There is a trade-off between minimizing the amount of resource minimizing the amount of resource reserved in the lower layer and disrupting
reserved in the lower layer and disrupting higher layer traffic higher layer traffic (i.e. moving the traffic to other TE-LSPs so that some LSPs
(i.e. moving the traffic to other TE-LSPs so that some LSPs can be can be released). Such traffic disruption MAY be allowed, but MUST be under the
released). Such traffic disruption MAY be allowed, but MUST be control of policy that can be configured by the operator. Any repositioning of
under the control of policy that can be configured by the operator. traffic MUST be as non-disruptive as possible (for example, using make-before-
Any repositioning of traffic MUST be as non-disruptive as possible break).
(for example, using 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 that
LSP that provides the TE-link, and so from the TE-links in the provides the TE-link, and so from the TE-links in the lower layer that are
lower layer that are traversed by the LSP. 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
Particular attention should be given to the inheritance of TE attention should be given to the inheritance of TE metric (which may be other
metric (which may be other than a strict sum of the metrics of the than a strict sum of the metrics of the component TE links at the lower layer),
component TE links at the lower layer), protection attributes, and protection attributes, and SRLG.
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
lose important information necessary to make LSPs in the higher important information necessary to make LSPs in the higher layer network
layer network reliable. SRLGs may be used to identify which lower- reliable. SRLGs may be used to identify which lower-layer LSPs share the same
layer LSPs share the same failure risk so that the potential risk failure risk so that the potential risk of the VNT becoming disjoint can be
of the VNT becoming disjoint can be minimized, and so that resource minimized, and so that resource disjoint protection paths can be set up in the
disjoint protection paths can be set up in the higher layer. How to higher layer. How to inherit the SRLG information from the lower layer to the
inherit the SRLG information from the lower layer to the upper upper layer needs more discussion and is out of scope of this document.
layer needs more discussion and is out of scope of this document.
draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
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
boundaries when computing a path for an LSP. For example, path computing a path for an LSP. For example, path computation MAY restrict the path
computation MAY restrict the path taken by an LSP to only the links 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
computation. For example, a TDM-LSP is routed over the topology example, a TDM-LSP is routed over the topology composed of TE links of the same
composed of TE links of the same TDM layer. In calculating the path TDM layer. In calculating the path for the LSP, the TED MAY be filtered to
for the LSP, the TED MAY be filtered to include only links where include only links where both end include requested LSP switching type. In this
both end include requested LSP switching type. In this way way hierarchical routing is done by using a TED filtered with respect to
hierarchical routing is done by using a TED filtered with respect switching capability (that is, with respect to particular layer).
to switching 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 produce a
MAY produce a route containing multiple layers/regions. The path is route containing multiple layers/regions. The path is computed over the multiple
computed over the multiple layers/regions even if the path is not layers/regions even if the path is not "connected" in the same layer as the
"connected" in the same layer as the endpoints of the path exist. endpoints of the path exist. Note that here we assume that triggered signaling
Note that here we assume that triggered signaling will be invoked will be invoked to make the path "connected", when the upper-layer signaling
to make the path "connected", when the upper-layer signaling
request arrives at the boundary node. request 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
only hops in the upper layer, in which case the boundary node is the upper layer, in which case the boundary node is responsible for triggered
responsible for triggered creation of the lower-layer FA-LSP using creation of the lower-layer FA-LSP using a path of its choice, or for the
a path of its choice, or for the selection of any available lower selection of any available lower layer LSP as a data link for the higher layer.
layer LSP as a data link for the higher layer. This mechanism is This mechanism is appropriate for environments where the TED is filtered in the
appropriate for environments where the TED is filtered in the higher layer, where separate routing instances are used per layer, or where
higher layer, where separate routing instances are used per layer, administrative policies prevent the higher layer from specifying paths through
or where administrative policies prevent the higher layer from the lower layer.
specifying 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
(virtual or real) into the higher layer, then the higher layer real) into the higher layer, then the higher layer signaling request may contain
signaling request may contain the TE link identifier and so the TE link identifier and so indicate the lower layer resources to be used. But
indicate the lower layer resources to be used. But in this case, in this case, the path of the lower layer LSP can be dynamically changed by the
the path of the lower layer LSP can be dynamically changed by the
lower layer at any time. 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
specifying the lower layer FA-LSP route. In this case, the boundary the lower layer FA-LSP route. In this case, the boundary node is responsible for
node is responsible for decision as to which it should use the path decision as to which it should use the path contained in the strict ERO or it
contained in the strict ERO or it should re-compute the path within 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 signaling
signaling request may also be encoded as loose ERO. In this request may also be encoded as loose ERO. In this situation, it is up to the
situation, it is up to the boundary node to decide whether it boundary node to decide whether it should a new lower-layer FA-LSP or it should
should a new lower-layer FA-LSP or it should use the existing use the existing lower-layer FA-LSPs.
lower-layer 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
upper-layer or an IGP adjacency can be brought up on the lower- an IGP adjacency can be brought up on the lower-layer FA-LSP.
layer FA-LSP.
5.8. LSP Resource Utilization 5.8. LSP Resource Utilization
draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
It MUST be possible to utilize network resources efficiently. It MUST be possible to utilize network resources efficiently. Particularly,
Particularly, resource usage in all layers SHOULD be optimized as a resource usage in all layers SHOULD be optimized as a whole (i.e., across all
whole (i.e., across all layers), in a coordinated manner, (i.e., layers), in a coordinated manner, (i.e., taking all layers into account). The
taking all layers into account). The number of lower-layer LSPs number of lower-layer LSPs carrying upper-layer LSPs SHOULD be minimized (note
carrying upper-layer LSPs SHOULD be minimized (Note that multiple 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 SHOULD be
have their traffic re-routed onto other LSPs are unnecessary and 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
regions. A PSC or L2SC LSP may or may not consume the maximum L2SC LSP may or may not consume the maximum reservable bandwidth of the TE link
reservable bandwidth of the TE link (FA LSP) that carries it. On (FA LSP) that carries it. On the other hand, a TDM, or LSC LSP always consumes a
the other hand, a TDM, or LSC LSP always consumes a fixed amount of fixed amount of bandwidth as long as it exists (and is fully instantiated)
bandwidth as long as it exists (and is fully instantiated) because 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
higher-layer LSP MAY be released so that lower-layer resources are LSP MAY be released so that lower-layer resources are released and can be
released and can be assigned to other uses. Note that if a small assigned to other uses. Note that if a small fraction of the available bandwidth
fraction of the available bandwidth of an FA-LSP is still in use, of an FA-LSP is still in use, the nested LSPs can also be re-routed to other FA-
the nested LSPs can also be re-routed to other FA-LSPs (optionally LSPs (optionally using the make-before-break technique) to completely free up
using the make-before-break technique) to completely free up the the FA-LSP. Alternatively, unused FA LSPs MAY be retained for future use.
FA-LSP. Alternatively, unused FA LSPs MAY be retained for future Release or retention of underutilized FA LSPs is a policy decision.
use. Release or retention of underutilized FA LSPs is a policy
decision.
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
rerouting of an FA LSP while keeping interface identifiers of FA LSP while keeping interface identifiers of corresponding TE links unchanged.
corresponding TE links unchanged. Further, this process MUST be Further, this process MUST be possible while the FA LSP is carrying traffic
possible while the FA LSP is carrying traffic (higher layer LSPs) (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
consider residual resources and the change of traffic demand across residual resources and the change of traffic demand across the region. By
the region. By creating the new FA LSPs, the network performance creating the new FA LSPs, the network performance such as maximum residual
such as maximum residual capacity may increase. capacity may increase.
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,
In this case, re-optimization of FA LSPs MAY be invoked according re-optimization of FA LSPs MAY be invoked according to policy.
to policy.
Any solution MUST include measures to protect against network Any solution MUST include measures to protect against network destabilization
destabilization caused by the rapid setup and teardown of LSPs as caused by the rapid setup and teardown of LSPs as traffic demand varies near a
traffic demand varies near a threshold. threshold.
Signaling of lower-layer LSPs SHOULD include a mechanism to rapidly Signaling of lower-layer LSPs SHOULD include a mechanism to rapidly advertise
advertise the LSP as a TE link and to coordinate into which routing the LSP as a TE link and to coordinate into which routing instances the TE link
instances the TE link should be advertised. 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-provision)
pre-provision) the set of lower layer LSPs that provide the VNT the set of lower layer LSPs that provide the VNT since this might reserve
since this might reserve bandwidth that could be used for other bandwidth that could be used for other LSPs in the absence of upper-layer
LSPs in the absence of upper-layer traffic. traffic.
However, in order to allow path computation of upper-layer LSPs
across the lower-layer, the lower-layer LSPs MAY be advertised into
the upper-layer as though they had been fully established, but
without actually establishing them. Such TE links that represent
the possibility of an underlying LSP are termed "virtual TE-links."
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
implementation MUST be under the control of operator policy. Note
that there is no requirement to support the creation of virtual TE-
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
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 will be dynamically created (triggered) as needed.
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.
If virtual TE-Links are used in place of pre-established LSPs, the draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
TE-links across the upper-layer can remain stable using pre-
computed paths while wastage of bandwidth within the lower-layer
and unnecessary reservation of adaptation ports at the border nodes
can be avoided.
The concept of the VNT can be extended to allow the virtual TE- However, in order to allow path computation of upper-layer LSPs across the
links to form part of the VNT. The combination of the fully lower-layer, the lower-layer LSPs MAY be advertised into the upper-layer as
provisioned TE-links and the virtual TE-links defines the VNT though they had been fully established, but without actually establishing them.
provided by the lower layer. Such TE links that represent the possibility of an underlying LSP are termed
"virtual TE-links." 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
implementation MUST be under the control of operator policy. Note that there is
no requirement to support the creation of virtual TE-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 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 will be dynamically created (triggered) as needed.
The solution SHOULD provide operations to facilitate the build-up If an upper-layer LSP that makes use of a virtual TE-Link is set up, the
of such virtual TE-links, taking into account the (forecast) underlying LSP MUST be immediately signaled in the lower layer.
traffic demand and available resource in the lower-layer.
Virtual TE-links MAY be modified dynamically (by adding or removing If virtual TE-Links are used in place of pre-established LSPs, the TE-links
virtual TE links, or changing their capacity) according to the across the upper-layer can remain stable using pre-computed paths while wastage
change of the (forecast) traffic demand and the available resource of bandwidth within the lower-layer and unnecessary reservation of adaptation
in the lower-layer. ports at the border nodes can be avoided.
Any solution MUST include measures to protect against network The solution SHOULD provide operations to facilitate the build-up of such
destabilization caused by the rapid changes in the virtual network virtual TE-links, taking into account the (forecast) traffic demand and
topology as traffic demand varies near a threshold. available resource in the lower-layer.
The VNT can be changed by setting up and/or tearing down virtual TE Virtual TE-links MAY be added, removed or modified dynamically (by changing
links as well as by modifying real links (i.e. the fully their capacity) according to the change of the (forecast) traffic demand and the
provisioned LSPs). available resource in the lower-layer. The maximum number of virtual TE links
that can be defined SHOULD be configurable.
The maximum number of virtual TE links that can be defined SHOULD Any solution MUST include measures to protect against network destabilization
be configurable. caused by the rapid changes in the virtual network topology as traffic demand
varies near a threshold.
How to design the VNT and how to manage it are out of scope of this The concept of the VNT can be extended to allow the virtual TE-links to form
document. part of the VNT. The combination of the fully provisioned TE-links and the
virtual TE-links defines the VNT provided by the lower layer. The VNT can be
changed by setting up and/or tearing down virtual TE links as well as by
modifying real links (i.e. the fully provisioned LSPs). How to design the VNT
and how to manage it are out of scope of this document.
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,
higher layer, the LSP MAY be verified for correct connectivity and the LSP MAY be verified for correct connectivity and data integrity. Such
data integrity. Such mechanisms are data technology-specific and mechanisms are data technology-specific and are beyond the scope of this
are beyond the scope of this document, but may be coordinated document, but may be coordinated through the GMPLS control plane.
through the GMPLS control plane.
draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
6. Security Considerations 6. Security Considerations
The current version of this document does not introduce any new The current version of this document does not introduce any new security
security considerations as it only lists a set of requirements. considerations as it only lists a set of requirements.
It is expected that solution documents will include a full analysis It is expected that solution documents will include a full analysis of the
of the security issues that any protocol extensions introduce. security issues that any protocol extensions introduce.
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. References 8. References
8.1. Normative Reference 8.1. Normative Reference
[RFC2119] Bradner, S., "Key words for use in RFCs to [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Indicate Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119, March 1997.
March 1997.
[RFC4202] K.Kompella and Y.Rekhter, "Routing Extensions in [RFC4202] K.Kompella and Y.Rekhter, "Routing Extensions in Support of
Support of Generalized Multi-Protocol Label Generalized Multi-Protocol Label Switching (GMPLS)," RFC4202,
Switching (GMPLS)," RFC4202, October 2005. October 2005.
[RFC4726] A.Farrel, J-P. Vasseur, and A.Ayyangar, "A Framework [RFC4726] A.Farrel, J-P. Vasseur, and A.Ayyangar, "A Framework for Inter-
for Inter-Domain Multiprotocol Label Switching Domain Multiprotocol Label Switching Traffic Engineering", RFC
Traffic Engineering", RFC 4726, November 2006. 4726, November 2006.
[RFC4206] K.Kompella and Y.Rekhter, "Label Switched Paths (LSP) [RFC4206] K.Kompella and Y.Rekhter, "Label Switched Paths (LSP) Hierarchy
Hierarchy with Generalized Multi-Protocol Label with Generalized Multi-Protocol Label Switching (GMPLS) Traffic
Switching (GMPLS) Traffic Engineering (TE)," Engineering (TE)," RFC4206, Oct. 2005.
RFC4206, Oct. 2005.
[RFC3945] E.Mannie (Ed.), "Generalized Multi-Protocol Label [RFC3945] E.Mannie (Ed.), "Generalized Multi-Protocol Label Switching
Switching (GMPLS) Architecture", RFC 3945, October (GMPLS) Architecture", RFC 3945, October 2004.
2004. [RFC4397] I.Bryskin and A. Farrel, "A Lexicography for the Interpretation of
[RFC4397] I.Bryskin and A. Farrel, "A Lexicography for the Generalized Multiprotocol Label Switching (GMPLS)
Interpretation of Generalized Multiprotocol Terminology within the Context of the ITU-T's Automatically
Label Switching (GMPLS) Terminology within the Switched Optical Network (ASON) Architecture", RFC 4397,
Context of the ITU-T's Automatically Switched
Optical Network (ASON) Architecture", RFC 4397,
February 2006. February 2006.
8.2. Informative References 8.2. Informative References
[MRN-EVAL] Le Roux, J.L., Brungard, D., Oki, E., Papadimitriou, D., [MRN-EVAL] Le Roux, J.L., Brungard, D., Oki, E., Papadimitriou, D., Shiomoto,
Shiomoto, K., Vigoureux, M.,"Evaluation of existing K., Vigoureux, M.,"Evaluation of existing GMPLS Protocols
GMPLS Protocols against Multi Layer and Multi Region against Multi Layer and Multi Region Networks (MLN/MRN)",
Networks (MLN/MRN)", draft-ietf-ccamp-gmpls-mrn-eval, draft-ietf-ccamp-gmpls-mrn-eval, work in progress.
work in progress.
[MPLS-GMPLS] K. Kumaki (Editor), "Interworking Requirements to draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
Support operation of MPLS-TE over GMPLS networks",
draft-ietf-ccamp-mpls-gmpls-interwork-reqts, work in
progress.
[DYN-HIER] Shiomoto, K., Rabbat, R., Ayyangar, A., Farrel, A. and [MPLS-GMPLS] K. Kumaki (Editor), "Interworking Requirements to Support
Ali, Z., "Procedures for Dynamically Signaled operation of MPLS-TE over GMPLS networks", draft-
Hierarchical Label Switched Paths", draft-ietf- ietf-ccamp-mpls-gmpls-interwork-reqts, work in progress.
ccamp-lsp-hierarchy-bis, work in progress.
[AUTO-MESH] Vasseur, JP., Le Roux, JL., et al., "Routing [DYN-HIER] Shiomoto, K., Rabbat, R., Ayyangar, A., Farrel, A. and Ali, Z.,
extensions for discovery of Multiprotocol (MPLS) "Procedures for Dynamically Signaled Hierarchical Label
Label Switch Router (LSR) Traffic Engineering (TE) Switched Paths", draft-ietf-ccamp-lsp-hierarchy-bis, work in
mesh membership", draft-ietf-ccamp-automesh, work in
progress. progress.
[AUTO-MESH] Vasseur, JP., Le Roux, JL., et al., "Routing extensions for
discovery of Multiprotocol (MPLS) Label Switch Router (LSR)
Traffic Engineering (TE) mesh membership", draft-ietf-ccamp-
automesh, work in progress.
9. Authors' Addresses 9. Authors' Addresses
Kohei Shiomoto Kohei Shiomoto
NTT Network Service Systems Laboratories NTT Network Service Systems Laboratories
3-9-11 Midori-cho, 3-9-11 Midori-cho,
Musashino-shi, Tokyo 180-8585, Japan 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
Francis Wellensplein 1, 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
skipping to change at page 21, line 4 skipping to change at page 20, line 4
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-04.txt August 2007
10.Contributors' Addresses 10.Contributors' Addresses
Eiji Oki Eiji Oki
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: oki.eiji@lab.ntt.co.jp Email: oki.eiji@lab.ntt.co.jp
skipping to change at page 21, line 34 skipping to change at page 20, line 36
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
11. Intellectual Property Considerations 11. 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
Intellectual Property Rights or other rights that might be claimed Property Rights or other rights that might be claimed to pertain to the
to pertain to the implementation or use of the technology described implementation or use of the technology described in this document or the extent
in this document or the extent to which any license under such to which any license under such rights might or might not be available; nor does
rights might or might not be available; nor does it represent that it represent that it has made any independent effort to identify any such rights.
it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be
Information on the procedures with respect to rights in RFC found in BCP 78 and BCP 79.
documents can be found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any Copies of IPR disclosures made to the IETF Secretariat and any assurances of
assurances of licenses to be made available, or the result of an licenses to be made available, or the result of an attempt made to obtain a
attempt made to obtain a general license or permission for the use general license or permission for the use of such proprietary rights by
of such proprietary rights by implementers or users of this implementers or users of this specification can be obtained from the IETF on-
specification can be obtained from the IETF on-line IPR repository 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,
copyrights, patents or patent applications, or other proprietary patents or patent applications, or other proprietary rights that may cover
rights that may cover technology that may be required to implement technology that may be required to implement this standard. Please address the
this standard. Please address the information to the IETF at ietf- information to the IETF at ietf-ipr@ietf.org.
ipr@ietf.org.
12. Full Copyright Statement 12. Full Copyright Statement
draft-ietf-ccamp-gmpls-mln-reqs-04.txt August 2007
Copyright (C) The IETF Trust (2007). This document is subject to Copyright (C) The IETF Trust (2007). This document is subject to the rights,
the rights, licenses and restrictions contained in BCP 78, and licenses and restrictions contained in BCP 78, and except as set forth therein,
except as set forth therein, the authors retain all their rights. the authors 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"
an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY
REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST, AND THE INTERNET ENGINEERING
IETF TRUST, AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT
WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY 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 ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS PARTICULAR PURPOSE.
FOR A PARTICULAR PURPOSE.
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