Network Working Group Kohei Shiomoto (NTT)
Internet Draft Dimitri Papadimitriou (Alcatel)
Jean-Louis Le Roux (France Telecom)
Martin Vigoureux (Alcatel)
Deborah Brungard (AT&T)
Expires: April 2007 October 2006
Requirements for GMPLS-based multi-region and
multi-layer networks (MRN/MLN)
draft-ietf-ccamp-gmpls-mln-reqs-01.txt
draft-ietf-ccamp-gmpls-mln-reqs-02.txt
Status of this Memo
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
This document may only be posted in an Internet-Draft.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six
months and may be updated, replaced, or obsoleted by other
documents at any time. It is inappropriate to use Internet-Drafts
as reference material or to cite them other than as "work in
progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html
This Internet-Draft will expire on December 2006. April 2007.
Copyright Notice
Copyright (C) The Internet Society (2006).
Abstract
Most of the initial efforts on Generalized MPLS (GMPLS) have been
related to environments hosting devices with a single switching
capability. The complexity raised by the control of such data
planes is similar to that seen in classical IP/MPLS networks.
By extending MPLS to support multiple switching technologies, GMPLS
provides a comprehensive framework for the control of a multi-
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
layered network of either a single switching technology or multiple
switching technologies. In GMPLS, a switching technology domain
defines a region, and a network of multiple switching types is
referenced in this document as a multi-region network (MRN). When
referring in general to a layered network, which may consist of
either a single or multiple regions, this document uses the term,
Multi-layer Network (MLN). This draft defines a framework for GMPLS
based multi-region/multi-layer networks and lists a set of
functional requirements.
Table of Contents
1. Introduction...................................................2
2. Conventions used in this document..............................4
3. Positioning....................................................4
3.1. Data plane layers and control plane regions..................5
3.2. Service layer networks.......................................5
3.3. Vertical and Horizontal interaction and integration..........6
4. Key concepts of GMPLS-based MLNs and MRNs......................7
4.1. Interface Switching Capability...............................7
4.2. Multiple Interface Switching Capabilities....................8
4.2.1. Networks with multi-switching-type-capable hybrid nodes....8
4.3. Integrated Traffic Engineering (TE) and Resource Control.....9
4.3.1. Triggered signaling.......................................10
4.3.2. FA-LSP....................................................10
4.3.3. Virtual network topology (VNT)............................11
5. Requirements..................................................11
5.1. Scalability.................................................11
5.2. LSP resource utilization....................................12
5.2.1. FA-LSP release Handling single-switching and setup..................................12
5.2.2. Virtual TE-Link...........................................13
5.3. LSP Attribute inheritance...................................14
5.4. Verification multi-switching-type-capable
nodes............................................................11
5.2. Advertisement of the LSP.....................................14 available adaptation resource..........12
5.3. Scalability.................................................12
5.4. Stability...................................................12
5.5. Disruption minimization.....................................14 minimization.....................................13
5.6. Stability...................................................15 LSP Attribute inheritance...................................13
5.7. Computing paths with and without nested signaling...........16 signaling...........14
5.8. Handling single-switching LSP resource utilization....................................15
5.8.1. FA-LSP release and multi-switching-type-capable
nodes............................................................17 setup..................................15
5.8.2. Virtual TE-Link...........................................16
5.9. Advertisement Verification of the available adaptation resource..........17 LSP.....................................17
6. Security Considerations.......................................17
7. References....................................................18 References....................................................17
7.1. Normative Reference.........................................18 Reference.........................................17
7.2. Informative References......................................18
8. Author's Addresses............................................19
9. Intellectual Property Considerations..........................20
10. Full Copyright Statement.....................................20
1. Introduction
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
Generalized MPLS (GMPLS) extends MPLS to handle multiple switching
technologies: packet switching, layer-two 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
switching technologies exist. The representation, in a GMPLS
control plane, of a switching technology domain is referred to as a
region [RFC4206].
A switching type describes the ability of a node to forward data of
a particular data plane technology, and uniquely identifies a
network region. A layer describes a data plane switching
granularity level (e.g. VC4, VC-12). A data plane layer is
associated with a region in the control plane (e.g. VC4 associated
to TDM, IP associated to PSC). However, more than one data plane
layer can be associated to the same region (e.g. both VC4 and VC12
are associated to TDM). Thus, a control plane region, identified by
its switching type value (e.g. TDM), can itself be sub-divided into
smaller granularity based on the bandwidth that defines the "data
plane switching layers" e.g. from VC-11 to VC4-256c. The Interface
Switching Capability Descriptor (ISCD) [RFC4202], identifying the
interface switching type, capability (ISC), the encoding type and the
switching bandwidth granularity, enable the characterization of the
associated layers.
A network comprising transport nodes with multiple data plane layers of
either the same ISC or different ISCs, controlled by a single GMPLS
control plane instance is called a Multi-Layer Network (MLN). To
differentiate a network supporting LSPs of different switching technologies (ISCs)
types from a single region network, a network supporting more than
one switching technology is called a Multi-Region Network (MRN). All MRNs are MLNs, by definition.
MLNs can be categorized according to the distribution of the ISCD
values amongst the LSRs:
- Each LSR may support just one ISCD, and the MLN set of LSRs may be
comprised
of
LSRs that support different ISCDs. Such LSRs are known as
single-switching-type-capable LSRs.
- Each LSR may support more than one ISCD at the same time so that
the network containing these LSR is an MLN. time. Such
LSRs are known
as multi-switching-type-capable LSRs, and can be further
classified as either "simplex" or "hybrid" nodes as defined in
Section 4.2.
- The MLN may be constructed from any combination of single-
switching-type-capable LSRs and multi-switching-type-capable
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
LSRs.
Since GMPLS provides a comprehensive framework for the control of
different switching capabilities, a single GMPLS instance may be
used to control the MLN enabling rapid service provisioning and
efficient traffic engineering across all switching capabilities. In
such networks, TE Links are consolidated into a single Traffic
Engineering Database (TED). Since this TED contains the information
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. Thus optimization of network resources can be
achieved across the whole MLN.
Consider, for example, a MRN consisting of packet-switch capable
routers and TDM cross-connects. Assume that a packet LSP is routed
between source and destination packet-switchi 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-
region/multi-layer networks. There is no intention to specify
solution-specific elements in this document. The applicability of
existing GMPLS protocols and any protocol extensions to the MRN/MLN
will be addressed in separate documents [MRN-EVAL].
2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
this document are to be interpreted as described in RFC 2119
[RFC2119].
3. Positioning
A multi-region network (MRN) is always a multi-layer network (MLN)
since the network devices on region boundaries bring together
different ISCs. A MLN, however, is not necessarily a MRN since
multiple layers could be fully contained within a single region.
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
For example, VC12, VC4, and VC4-4c are different layers of the TDM
region.
3.1. Data plane layers and control plane regions
A data plane layer is a collection of network resources capable of
terminating and/or switching data traffic of a particular format.
These resources can be used for establishing LSPs or connectionless
traffic delivery. For example, VC-11 and VC4-64c represent two
different layers.
From the control plane viewpoint, an LSP region is defined as a set
of one or more data plane layers that share the same type of
switching technology, that is, the same switching type. For example,
VC-11 and VC-4 layers are part of the same TDM region. The
currently defined regions are: PSC, L2SC, TDM, LSC, and FSC regions.
Hence, an LSP region is a technology domain (identified by the ISC
type) 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 of links (i.e. TE links). For
example VC-11 and VC4-64c capable TE links are part of the same TDM
region. Multiple layers 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 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.
3.2. Service layer networks
A service provider's network may be divided into different service
layers. The customer's network is considered from the provider's
perspective as the highest service layer. It interfaces to the
highest service layer of the service provider's network.
Connectivity across the highest service layer of the service
provider's network may be provided with support from successively
lower service layers. Service layers are realized via a hierarchy
of network layers located generally in several regions and commonly
arranged according to the switching capabilities of network devices.
For instance some customers purchase Layer 1 (i.e. transport)
services from the service provider, some Layer 2 (e.g. ATM), while
others purchase Layer 3 (IP/MPLS) services. The service provider
realizes the services by a stack of network layers located within
one or more network regions. The network layers are commonly
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
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 multi-region/multi-layer network. For example, a
Layer 1 service (realized via the network layers of TDM, and/or LSC,
and/or FSC regions) may support a Layer 2 network (realized via ATM
VP/VC) which may itself support a Layer 3 network (IP/MPLS region).
The supported data plane relationship is a data-plane client-server
relationship where the lower layer provides a service for the
higher layer using the data links realized in the lower layer.
Services provided by a GMPLS-based multi-region/multi-layer network
are referred to as "Multi-region/Multi-layer network services". For
example, legacy IP and IP/MPLS networks can be supported on top of
multi-region/multi-layer networks. It has to be emphasized that
delivery of such diverse services is a strong motivator for the
deployment of multi-region/multi-layer networks.
A customer network may be provided on top of a server GMPLS-based
MRN/MLN which is operated by a service provider. For example, a
pure IP and/or an IP/MPLS network can be provided on top of GMPLS-
based packet over optical networks [IW-MIG-FW]. The relationship
between the networks is a client/server relationship and, such
services are referred to as "MRN/MLN services". In this case, the
customer network may form part of the MRN/MLN, or may be partially
separated, for example to maintain separate routing information but
retain common signaling.
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
them. 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 thus 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's networks
that are based on multiple layers, switching technologies, or ISCDs.
Horizontal interaction is defined as the protocol exchange between
network controllers that manage transport nodes within a given
layer or region (i.e. nodes with the same switching capability).
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
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
the same network layer, is currently being evaluated as part of the
inter-domain work [Inter-domain], 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 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 in a network that supports IP/MPLS over TDM
switching could be described as vertical and horizontal integration
in the case where each network belongs to a separate routing area.
4. Key concepts of GMPLS-based MLNs and MRNs
A network comprising transport nodes with multiple data plane
layers of either the same ISC or different ISCs, controlled by a
single GMPLS control plane instance, is called a Multi-Layer
Network (MLN). A sub-set of MLNs consists of networks supporting
LSPs of different switching technologies (ISCs). A network
supporting more than one switching technology is called a Multi-
Region Network (MRN).
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
type) describes the ability of a node to forward data of a
particular data plane technology, and uniquely identifies a network
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
Capability Descriptor (ISCD) attribute (sub-TLV) of a TE link end
associated with a particular link interface [RFC4202]. Apart from
the ISC, the ISCD contains 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.
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
TE link end advertisements may contain multiple ISCDs. This can be
interpreted as advertising a multi-layer (or multi-switching) TE
link end. That is, the TE link end is present in multiple layers.
4.2. Multiple Interface Switching Capabilities
In an MLN, network elements may be single-switching or multi-
switching-type-capable nodes. Single-switching type capable nodes
advertise the same ISC value as part of their ISCD sub-TLV(s) to
describe the termination capabilities of their TE Link(s). This
case is described in [RFC4202].
Multi-switching-type-capable LSRs are classified as "simplex" or
"hybrid" nodes. Simplex and hybrid nodes are categorized according
to the way they advertise these multiple ISCs:
- A simplex node can terminate links with different switching
capabilities each of them connected to the node by a single link
interface. So, it advertises several TE Links each with a single
ISC value as part of its ISCD sub-TLVs. For example, an LSR with
PSC and TDM links each of which is connected to the LSR via single
interface.
- A hybrid node can terminate links with different switching
capabilities terminating on the same interface. So, it advertises
at least one TE Link containing more than one ISCDs with different
ISC values. For example, a node comprising of PSC and TDM links,
which are interconnected via internal links. The external
interfaces connected to the node have both PSC and TDM capability.
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
The network contains at least one hybrid node, zero or more simplex
nodes, and a set of single-switching-type-capable nodes.
Figure 5a shows an example hybrid node. The hybrid node has two
switching elements (matrices), which support, for instance, TDM and
PSC switching respectively. The node terminates a PSC and a TDM
link (Link1 and Link2 respectively). It also has an internal link
connecting the two swtching switching elements.
The two switching elements are internally interconnected in such a
way that it is possible to terminate some of the resources of, say,
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
Link2 and provide adaptation for PSC traffic received/sent over the
PSC interface (#b). This situation is modeled in GMPLS by
connecting the local end of Link2 to the TDM switching element via
an additional interface realizing the termination/adaptation
function. Two ways are possible to set up PSC LSPs. Available
resource advertisement e.g. Unreserved and Min/Max LSP Bandwidth
should cover both two ways.
Network element
.............................
: -------- :
: | PSC | :
Link1 -------------<->--|#a | :
: +--<->---|#b | :
: | -------- :
TDM : | ---------- :
+PSC : +--<->--|#c TDM | :
Link2 ------------<->--|#d | :
: ---------- :
:............................
Figure 5a. Hybrid node.
4.3. Integrated Traffic Engineering (TE) and Resource Control
In GMPLS-based multi-region/multi-layer networks, TE Links are
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
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 LSPs (see Section
4.3.3)
- provisioning of end-to-end LSPs with dynamic triggering of FA
LSPs
Note that in a multi-layer/multi-region network that includes
multi-switching-type-capable nodes, an explicit route used to
establish an end-to-end LSP can specify nodes that belong to
different layers or regions. In this case, a mechanism to control
the dynamic creation of FA LSPs may be required.
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
There is a full spectrum of options to control how FA LSPs are
dynamically established. The process can be subject to the control
of a policy, which may be set by a management component, and which
may require that the management plane is consulted at the time that
the FA LSP is established. Alternatively, the FA LSP can be
established at the request of the control plane without any
management control.
4.3.1. Triggered signaling
When an LSP crosses the boundary from an upper to a lower layer, it
may be nested into a lower layer FA LSP that crosses the lower
layer. From a signaling perspective, there are two alternatives to
establish the lower layer FA LSP: static (pre-provisioned) and
dynamic (triggered). Pre-provisioned FA-LSP will be initiated
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 may be established dynamically. Such a mechanism is
referred to as "triggered signaling".
4.3.2. FA-LSP
Once an LSP is created across a layer, it can be used as a data
link in an upper layer.
Furthermore, it can be advertised as a TE-link, allowing other
nodes to consider the LSP as a TE link for their path computation
[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 TE-link as which the FA-LSP is advertised is
called an 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. A 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)
LSP Hierarchy. A set of FA-LSPs across or within a lower layer can
be used during path selection by a higher layer LSP. Likewise, the
higher layer LSPs may be carried over dynamic data links realized
via LSPs (just as they are carried over any "regular" static data
links). This process requires the nesting of LSPs 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].
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
If a lower layer LSP is not advertised as an FA, it can still be
used to carry higher layer LSPs across the lower layer. For example,
if the LSP is set up 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.
4.3.3. Virtual network topology (VNT)
A set of one or more of lower-layer LSPs provides information for
efficient path handling in upper-layer(s) of the MLN, or, in other
words, provides a virtual network topology (VNT) to the upper-
layers. For instance, a set of LSPs, each of which is supported by
an LSC LSP, provides a virtual network topology to the layers of a
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 virtual network topology is configured by setting up or
tearing down the lower layer LSPs. By using GMPLS signaling and
routing protocols, the virtual network topology can be adapted to
traffic demands.
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 [MAMLTE]. 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
5.1. Scalability
The MRN/MLN relies on a unified traffic engineering
5.1.Handling single-switching and routing
model. multi-switching-type-capable nodes
The TED in each LSR is populated with TE-links from all
layers of all regions. This may lead to a huge amount MRN/MLN can consist of
information that has to be flooded single-switching-type-capable and stored within the network.
Furthermore, multi-
switching-type-capable nodes. The path computation times, which may be of great
importance during restoration, will depend on the size of mechanism in the TED.
Thus MRN/MLN routing mechanisms MUST
MLN SHOULD be designed able to scale well with
an increase compute paths consisting of any combination
of such nodes.
Both single-switching-type-capable and multi-switching-type-capable
(simplex or hybrid) nodes could play the following:
- Number role of nodes
- Number layer boundary.
MRN/MLN Path computation SHOULD handle TE topologies built of TE-links (including FA-LSPs)
- Number any
combination of LSPs
- Number nodes
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
5.2. Advertisement of regions the available adaptation resource
A hybrid node SHOULD maintain resources and layers
- Number of ISCDs per TE-link.
Further, design of advertise the routing protocols MUST NOT prevent TE resource
information filtering based on ISCDs. Signaling protocol its internal links, the links required for vertical
(layer) integration. Likewise, path computation elements SHOULD be
able to operate on partial TE information.
5.2. LSP resource utilization
It MUST be possible
prepared to utilize network use the availability of termination/adaptation
resources efficiently.
Particularly, resource usage in all layers SHOULD be optimized as a
whole (i.e., across all layers), constraint in a coordinated manner, (i.e.,
taking all layers into account). MRN/MLN path computations to reduce
the higher layer LSP setup blocking probability because of the lack
of necessary termination/ adaptation resources in the lower
layer(s).
The number advertisement of lower-layer LSPs
carrying upper-layer LSPs SHOULD be minimized (Note that multiple the adaptation capability to terminate LSPs MAY be used for load balancing). Unneccesary lower-layer LSPs,
which would not carry any of
lower-region and forward traffic by rerouting in the traffic over upper-region is REQUIRED,
as it provides critical information when performing multi-region
path computation.
The mechanism SHOULD cover the case where the upper-layer links
which are directly connected to alternative upper-layer switching element and
the ones which are connected through internal links between upper-
layer element and lower-layer LSPs, SHOULD be avoided.
5.2.1. FA-LSP release element coexist (See section 4.2.1).
5.3. Scalability
The MRN/MLN relies on a unified traffic engineering and setup
Statistical multiplexing can only be employed routing
model. The TED in PSC and L2SC each LSR is populated with TE-links from all
layers of all regions. A PSC or L2SC LSP may or This may not consume lead to a huge amount of
information that has to be flooded and stored within the maximum
reservable bandwidth network.
Furthermore, path computation times, which may be of great
importance during restoration, will depend on the FA LSP that carries it. On size of the other
hand, a TDM, or LSC LSP always consumes a fixed amount TED.
Thus MRN/MLN routing mechanisms MUST be designed to scale well with
an increase of bandwidth
as long as it exists (and is fully instantiated) because
statistical multiplexing is not available.
If there is low traffic demand, some FA LSPs that do not carry any
LSP MAY be released so that lower-layer resources are released.
Note that if a small fraction of the available bandwidth following:
- Number of an FA-
LSP is still in use, the nested LSPs can also be re-routed to other
FA-LSPs (optionally using the make-before-break technique) to
complete free up the FA-LSP. Alternatively, the FA LSPs MAY be
retained for future use. Release or retention nodes
- Number of underutilized FA
LSPs is a policy decision.
As part TE-links (including FA-LSPs)
- Number of the re-optimization process, the solution MUST allow
rerouting LSPs
- Number of an FA LSP while keeping interface identifiers regions and layers
- Number of
corresponding TE links unchanged. ISCDs per TE-link.
Further, this process design of the routing protocols MUST NOT prevent TE
information filtering based on ISCDs. Signaling protocol SHOULD be
possible while the FA LSP is carrying traffic (higher layer LSPs)
with minimal disruption
able to the traffic.
Additional FA LSPs MAY also be created based operate on partial TE information.
5.4.Stability
Path computation is dependent on policy, which might
consider residual resources and the change network topology and
associated link state. The path computation stability of traffic demand across
the region. By creating an upper
layer may be impaired if the new FA LSPs, VNT changes frequently and/or if the network performance
such as maximum residual capacity may increase.
As the number
status and TE parameters (TE metric for instance) of FA LSPs grows, links in the residual resource may decrease.
virtual network topology changes frequently.
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
In this case, re-optimization context, robustness of FA LSPs MAY be invoked according
to policy.
Any solution MUST include measures the VNT is defined as the capability
to protect against network
destabilization smooth changes that may occur and avoid their propagation into
higher layers. Changes of the VNT may be caused by the rapid setup creation,
deletion, or modification of several LSPs.
Creation, deletion and teardown modification of LSPs as MAY be triggered by
adjacent layers or through operational actions to meet traffic
demand varies near a threshold.
5.2.2. Virtual TE-Link
It may changes, topology changes, signaling requests from the upper
layer, and network failures. Routing robustness SHOULD be considered disadvantageous traded
with adaptability with respect to fully instantiate (i.e.
pre-provision) the set change of incoming traffic
requests.
A full mesh of lower layer LSPs that provide MAY be created between every pair of border
nodes of the VNT
since this might reserve bandwidth higher layer. The merit of a full mesh of PSC TE-LSPs
is that could be it provides stability to the higher layer routing. That is,
the TED or forwarding table used for other
LSPs in the absence higher layer of a PSC-LSR
is not impacted by routing changes within the upper-layer traffic.
However, in order lower-layer (e.g.,
TDM layer). Further, there is always full PSC reachability and
immediate access to allow path computation of upper-layer bandwidth to support LSPs
across in the lower-layer, higher layer.
But it also has significant drawbacks, since it requires 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
maintenance of an underlying LSP are termed "virtual TE-link".
It is an implementation choice at a boundary node whether to create
virtual TE-links, n^2 RSVP-TE sessions, which may be quite CPU and the choice
memory consuming (scalability impact). Also this may lead to
significant bandwidth wastage if available MUST be under the
control LSPs with a certain amount of operator policy.
reserved bandwidth are used.
Note that there is no requirement to
support the creation use of virtual TE-links, since real TE-links (with
established LSPs) may be used, solves the bandwidth wastage
issue, and even if there are no TE-links
(virtual or real) advertised to may reduce the higher layer, it is possible control plane overload.
5.5.Disruption minimization
When reconfiguring the VNT according to
route a higher layer change in traffic demand,
the upper-layer LSP into might be disrupted. Such disruption to the
upper layers MUST be minimized.
When residual resource decreases to a certain level, some lower
layer on the assumptions that
proper hierarchical LSPs MAY be released according to local or network policies.
There is a trade-off between minimizing the amount of resource
reserved 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, and disrupting higher layer traffic
(i.e. moving the underlying LSP traffic to other TE-LSPs so that some LSPs can be
released). Such traffic disruption MAY be allowed but MUST be immediately signaled in under
the lower layer.
If virtual TE-Links are used in place control of pre-established LSPs, the
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 policy that can be extended to allow the virtual TE-
links to form part of the VNT. The combination of the fully
provisioned TE-links and the virtual TE-links defines the VNT
provided configured by the lower layer.
The solution SHOULD provide operations to facilitate the build-up
of such virtual TE-links, taking into account the (forecast)
traffic demand and available resource in the lower-layer.
Virtual TE-links MAY be modified dynamically (by adding or removing
virtual TE links, or chancing their capacity) according to the
change operator. Any
repositioning of the (forecast) traffic demand and the available resource
in the lower-layer.
Any solution MUST include measures to protect against network
destabilization caused by the rapid changes in the virtual network
topology as traffic demand varies near a threshold.
The VNT can be changed by setting up and/or tearing down virtual TE
links as well non-disruptive as by modifying real links (i.e. the fully
provisioned LSPs).
The maximum number of virtual TE links that can be defined SHOULD
be configurable.
How to design the VNT and how to manage it are out of scope of this
document.
5.3. LSP possible (for
example, using make-before-break).
5.6.LSP Attribute inheritance
TE-Link parameters SHOULD be inherited from the parameters of the
LSP that provides the TE-link, and so from the TE-links in the
lower layer that are traversed by the LSP.
These include:
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
- Interface Switching Capability
- TE metric
- Maximum LSP bandwidth per priority level
- Unreserved bandwidth for all priority levels
- Maximum Reservable bandwidth
- Protection attribute
- Minimum LSP bandwidth (depending on the Switching Capability)
Inheritance rules MUST be applied based on specific policies.
Particular attention should be given to the inheritance of TE
metric (which may be other than a strict sum of the metrics of the
component TE links at the lower layer) and protection attributes.
5.4. Verification of the
5.7.Computing paths with and without nested signaling
Path computation MAY take into account LSP
When a lower region and layer LSP is established for use as a data link by
boundaries when computing a
higher layer, the LSP MAY be verified path for correct connectivity and
data integrity. Such mechanisms are data technology-specific and
are beyond the scope of this document, but may be coordinated
through the GMPLS control plane.
5.5. Disruption minimization
When reconfiguring an LSP. For example, path
computation MAY restrict the VNT according path taken by an LSP to only the links
whose interface switching capability is PSC.
Interface switching capability is used as a change constraint in traffic demand, path
computation. For example, a TDM-LSP is routed over the upper-layer LSP might be disrupted. Such disruption to topology
composed of TE links of the
upper layers MUST same TDM layer. In calculating the path
for the LSP, the TED MAY be minimized.
When residual resource decreases filtered to include only links where
both end include requested LSP switching type. In this way
hierarchical routing is done by using a certain level, some lower
layer LSPs MAY be released according TED filtered with respect
to local or network policies.
There switching capability (that is, with respect to particular layer).
If triggered signaling is allowed, the path computation mechanism
MAY produce a trade-off between minimizing route containing multiple layers/regions. The path is
computed over the amount of resource
reserved multiple layers/regions even if the path is not
"connected" in the lower layer and disrupting higher same layer traffic
(i.e. moving the traffic to other TE-LSPs so that some LSPs can be
released). Such traffic disruption MAY be allowed but MUST be under as the control endpoints of policy the path exist.
Note that can here we assume that triggered signaling will be configured by invoked
to make the operator. Any
repositioning of traffic MUST be as non-disruptive as possible (for
example, using make-before-break).
5.6. Stability
Path computation is dependent on the network topology and
associated link state. The path computation stability of an upper
layer may be impaired if "connected", when the VNT changes frequently and/or if upper-layer signaling
request arrives at the
status and TE parameters (TE metric for instance) of links boundary node.
The upper-layer signaling request may contain an ERO that includes
only hops in the
virtual network topology changes frequently.
In this context, robustness of upper layer, in which case the VNT boundary node is defined as the capability
to smooth changes that may occur and avoid their propagation into
higher layers. Changes
responsible for triggered creating of the VNT may be caused by the creation,
deletion, or modification of several LSPs.
Creation, deletion and modification lower-layer FA-LSP using
a path of LSPs MAY be triggered by
adjacent layers its choice, or through operational actions to meet traffic
demand changes, topology changes, signaling requests from the upper
layer, and network failures. Routing robustness SHOULD be traded
with adaptability with respect to for the change of incoming traffic
requests.
A full mesh of LSPs MAY be created between every pair of border
nodes selection of any available lower
layer LSP as a data link for the higher layer. The merit of a full mesh of PSC TE-LSPs This mechanism is that it provides stability to the higher layer routing. That is,
appropriate for environments where the TED or forwarding table used is filtered in the
higher layer of an PSC-LSR
is not impacted by layer, where separate routing changes within the lower-layer (e.g.,
TDM layer). Further, there is always full PSC reachability and
immediate access to bandwidth to support LSPs in instances are used per layer,
or where administrative policies prevent the higher layer from
specifying paths through the lower layer.
But it also
Obviously, if the lower layer LSP has significant drawbacks, since it requires been advertised as a TE link
(virtual or real) into the
maintenance of n^2 RSVP-TE sessions, which higher layer, then the higher layer
signaling request may be quite CPU contain the TE link identifier and
memory consuming (scalability impact). Also this may lead so
indicate the lower layer resources to
significant bandwidth wastage if LSPs with a certain amount of
reserved bandwidth are be used.
Note that But in this case,
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
the use path of virtual TE-links solves the bandwidth wastage
issue, and may reduce the control plane overload.
5.7. Computing paths with and without nested signaling
Path computation MAY take into account lower layer LSP region and can be dynamically changed by the
lower layer
boundaries when computing a path for an LSP. For example, path
computation MAY restrict at any time.
Alternatively, the path taken by upper-layer signaling request may contain an LSP to only ERO
specifying the links
whose interface switching capability is PSC.
Interface switching capability lower layer FA-LSP route. In this case, the boundary
node is used responsible for decision as a constraint in path
computation. For example, a TDM-LSP is routed over to which it should use the topology
composed of TE links of path
contained in the same TDM layer. In calculating strict ERO or it should re-compute the path
for within
in the LSP, lower-layer.
Even in case the TED MAY be filtered to include only links where
both end include requested LSP switching type. lower-layer FA-LSPs are already established, a
signaling request may also be encoded as loose ERO. In this way
hierarchical routing
situation, it is done by using a TED filtered with respect up to switching capability (that is, with respect the boundary node to particular layer).
If triggered signaling is allowed, decide whether it
should a new lower-layer FA-LSP or it should use the path computation mechanism
MAY produce existing
lower-layer FA-LSPs.
The lower-layer FA-LSP can be advertised just as an FA-LSP in the
upper-layer or an IGP adjacency can be brought up on the lower-
layer FA-LSP.
5.8. LSP resource utilization
It MUST be possible to utilize network resources efficiently.
Particularly, resource usage in all layers SHOULD be optimized as a route containing multiple layers/regions.
whole (i.e., across all layers), in a coordinated manner, (i.e.,
taking all layers into account). The path is
computed number of lower-layer LSPs
carrying upper-layer LSPs SHOULD be minimized (Note that multiple
LSPs MAY be used for load balancing). Unneccesary lower-layer LSPs,
which would not carry any traffic by rerouting the traffic over it
to alternative lower-layer LSPs, SHOULD be avoided.
5.8.1. FA-LSP release and setup
Statistical multiplexing can only be employed in PSC and L2SC
regions. A PSC or L2SC LSP may or may not consume the multiple layers/regions even maximum
reservable bandwidth of the FA LSP that carries it. On the other
hand, a TDM, or LSC LSP always consumes a fixed amount of bandwidth
as long as it exists (and is fully instantiated) because
statistical multiplexing is not available.
If there is low traffic demand, some FA LSPs that do not carry any
LSP MAY be released so that lower-layer resources are released.
Note that if a small fraction of the path available bandwidth of an FA-
LSP is not
"connected" still in use, the same layer as the endpoints of the path exist.
Note that here we assume that triggered signaling will nested LSPs can also be invoked re-routed to make the path "connected", when the upper-layer signaling
request arrives at other
FA-LSPs (optionally using the boundary node.
The upper-layer signaling request may contain an ERO that includes
only hops in make-before-break technique) to
complete free up the upper layer, in which case FA-LSP. Alternatively, the boundary node is
responsible FA LSPs MAY be
retained for triggered creating future use. Release or retention of the lower-layer FA-LSP using underutilized FA
LSPs is a path policy decision.
As part of its choice, or for the selection re-optimization process, the solution MUST allow
rerouting of any available lower
layer an FA LSP as a data link for the higher layer. This mechanism is
appropriate for environments where while keeping interface identifiers of
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
corresponding TE links unchanged. Further, this process MUST be
possible while the TED FA LSP is filtered in the
higher layer, where separate routing instances are used per layer,
or where administrative policies prevent the higher carrying traffic (higher layer from
specifying paths through LSPs)
with minimal disruption to the lower layer.
Obviously, if traffic.
Additional FA LSPs MAY also be created based on policy, which might
consider residual resources and the lower layer LSP has been advertised as a TE link
(virtual or real) into change of traffic demand across
the region. By creating the higher layer, then new FA LSPs, the higher layer
signaling request network performance
such as maximum residual capacity may contain increase.
As the TE link identifier and so
indicate number of FA LSPs grows, the lower layer resources to be used. But in residual resource may decrease.
In this case,
the path re-optimization of the lower layer LSP can FA LSPs MAY be dynamically changed invoked according
to policy.
Any solution MUST include measures to protect against network
destabilization caused by the
lower layer at any time.
Alternatively, the upper-layer signaling request rapid setup and teardown of LSPs as
traffic demand varies near a threshold.
5.8.2. Virtual TE-Link
It may contain an ERO
specifying be considered disadvantageous to fully instantiate (i.e.
pre-provision) the set of lower layer FA-LSP route. In this case, LSPs that provide the boundary
node is responsible VNT
since this might reserve bandwidth that could be used for decision as to which it should use the path
contained other
LSPs in the strict ERO or it should re-compute absence of the path within upper-layer traffic.
However, in order to allow path computation of upper-layer LSPs
across the lower-layer.
Even in case lower-layer, the lower-layer FA-LSPs are already 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-link".
It is an implementation choice at a
signaling request boundary node whether to create
virtual TE-links, and the choice if available 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 also be encoded as loose ERO. In this
situation, it is up used, and even if there are no TE-links
(virtual or real) advertised to the boundary node to decide whether higher layer, it
should is possible to
route a new lower-layer FA-LSP or it should use higher layer LSP into a lower layer on the existing
lower-layer FA-LSPs.
The lower-layer FA-LSP can assumptions that
proper hierarchical LSPs in the lower layer will be advertised just dynamically
created (triggered) as needed.
If an FA-LSP 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
TE-links across the upper-layer or an IGP adjacency can be brought up on remain stable using pre-
computed paths while wastage of bandwidth within the lower-
layer FA-LSP.
5.8. Handling single-switching lower-layer
and multi-switching-type-capable unnecessary reservation of adaptation ports at the border nodes
The MRN/MLN
can consist of single-switching-type-capable and multi-
switching-type-capable nodes. be avoided.
The path computation mechanism in concept of the
MLN SHOULD VNT can be able extended to compute paths consisting allow the virtual TE-
links to form part of any the VNT. The combination of such nodes.
Both single-switching-type-capable the fully
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
provisioned TE-links 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
5.9. Advertisement of virtual TE-links defines the available adaptation resource
A hybrid node VNT
provided by the lower layer.
The solution SHOULD maintain resources and advertise provide operations to facilitate the build-up
of such virtual TE-links, taking into account the (forecast)
traffic demand and available resource
information on its internal links, in the links required for vertical
(layer) integration. Likewise, path computation elements SHOULD lower-layer.
virtual TE-links MAY be
prepared modified dynamically (by adding or removing
virtual TE links, or chancing their capacity) according to use the availability
change of termination/adaptation
resources as a constraint the (forecast) traffic demand and the available resource
in MRN/MLN path computations to reduce the higher layer LSP setup blocking probability because of lower-layer.
Any solution MUST include measures to protect against network
destabilization caused by the lack
of necessary termination/ adaptation resources rapid changes in the lower
layer(s). virtual network
topology as traffic demand varies near a threshold.
The advertisement 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).
The maximum number of virtual TE links that can be defined SHOULD
be configurable.
How to design the adaptation capability VNT and how to terminate LSPs manage it are out of scope of this
document.
5.9. Verification of
lower-region and forward traffic in the upper-region LSP
When a lower layer LSP is REQUIRED, established for use as it provides critical information when performing multi-region
path computation.
The mechanism SHOULD cover the case where a data link by a
higher layer, the upper-layer links
which LSP MAY be verified for correct connectivity and
data integrity. Such mechanisms are directly connected to upper-layer switching element data technology-specific and
the ones which
are connected beyond the scope of this document, but may be coordinated
through internal links between upper-
layer element and lower-layer element coexist (See section 4.2.1). the GMPLS control plane.
6. Security Considerations
The current version of this document does not introduce any new
security considerations as it only lists a set of requirements. In
the future versions, new security requirements may be added.
7. References
7.1. Normative Reference
[RFC2119] Bradner, S., "Key words for use in RFCs to
Indicate Requirement Levels", BCP 14, RFC 2119,
March 1997.
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
[RFC3979] Bradner, S., "Intellectual Property Rights in IETF
Technology", BCP 79, RFC 3979, March 2005.
[RFC4202] K.Kompella and Y.Rekhter, "Routing Extensions in
Support of Generalized Multi-Protocol Label
Switching (GMPLS)," RFC4202, October 2005.
[Inter-domain] A.Farrel, J-P. Vasseur, and A.Ayyangar, "A
framework for inter-domain MPLS traffic
engineering," draft-ietf-ccamp-inter-domain-
framework, work in progress.
[RFC4206] K.Kompella and Y.Rekhter, "Label Switched Paths (LSP)
Hierarchy with Generalized Multi-Protocol Label
Switching (GMPLS) Traffic Engineering (TE),"
RFC4206, Oct. 2005.
[STITCH] Ayyangar, A. and Vasseur, JP., "Label Switched Path
Stitching with Generalized MPLS Traffic Engineering",
draft-ietf-ccamp-lsp-stitching, work in progress.
[RFC4204] J. Lang, "Link management protocol (LMP)," RFC4204,
October 2005.
[RFC3945] E.Mannie (Ed.), "Generalized Multi-Protocol Label
Switching (GMPLS) Architecture", RFC 3945, October
2004.
7.2. Informative References
[MAMLTE] K. Shiomoto et al., "Multi-area multi-layer traffic
engineering using hierarchical LSPs in GMPLS
networks", draft-shiomoto-multiarea-te, work in
progress.
[MRN-EVAL] Le Roux, J.L., Brungard, D., Oki, E., Papadimitriou, D.,
Shiomoto, K., Vigoureux, M.,"Evaluation of existing
GMPLS Protocols against Multi Layer and Multi Region
Networks (MLN/MRN)", draft-leroux-ccamp-gmpls-mrn-
eval, draft-ietf-ccamp-gmpls-mrn-eval,
work in progress.
[IW-MIG-FW] Shiomoto, K., Papadimitriou, D., Le Roux, J.L.,
Brungard, D., Oki, E., Inoue, I., " Framework for
IP/MPLS-GMPLS interworking in support of IP/MPLS to
GMPLS migration ", draft-ietf-ccamp-mpls-gmpls-
interwork-fmwk-00.txt, work in progress.
[AUTO-MESH] Vasseur, JP., Le Roux, JL., et al., "Routing
extensions for discovery of Multiprotocol (MPLS)
Label Switch Router (LSR) Traffic Engineering (TE)
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
mesh membership", draft-ietf-ccamp-automesh, work in
progress.
8. Author's Addresses
Kohei Shiomoto
NTT Network Service Systems Laboratories
3-9-11 Midori-cho,
Musashino-shi, Tokyo 180-8585, Japan
Email: shiomoto.kohei@lab.ntt.co.jp
Dimitri Papadimitriou
Alcatel
Francis Wellensplein 1,
B-2018 Antwerpen, Belgium
Phone : +32 3 240 8491
Email: dimitri.papadimitriou@alcatel.be
Jean-Louis Le Roux
France Telecom R&D,
Av Pierre Marzin,
22300 Lannion, France
Email: jeanlouis.leroux@orange-ft.com
Martin Vigoureux
Alcatel
Route de Nozay, 91461 Marcoussis cedex, France
Phone: +33 (0)1 69 63 18 52
Email: martin.vigoureux@alcatel.fr
Deborah Brungard
AT&T
Rm. D1-3C22 - 200
S. Laurel Ave., Middletown, NJ 07748, USA
Phone: +1 732 420 1573
Email: dbrungard@att.com
Contributors
Eiji Oki (NTT Network Service Systems Laboratories)
3-9-11 Midori-cho, Musashino-shi, Tokyo 180-8585, Japan
Phone: +81 422 59 3441 Email: oki.eiji@lab.ntt.co.jp
Ichiro Inoue (NTT Network Service Systems Laboratories)
3-9-11 Midori-cho, Musashino-shi, Tokyo 180-8585, Japan
Phone: +81 422 59 3441 Email: ichiro.inoue@lab.ntt.co.jp
Emmanuel Dotaro (Alcatel)
draft-ietf-ccamp-gmpls-mln-reqs-02.txt October 2006
Route de Nozay, 91461 Marcoussis cedex, France
Phone : +33 1 6963 4723 Email: emmanuel.dotaro@alcatel.fr
9. Intellectual Property Considerations
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed
to pertain to the implementation or use of the technology described
in this document or the extent to which any license under such
rights might or might not be available; nor does it represent that
it has made any independent effort to identify any such rights.
Information on the procedures with respect to rights in RFC
documents can be found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use
of such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository
at http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at ietf-
ipr@ietf.org.
The IETF has been notified by Tellabs Operations, Inc. of
intellectual property rights claimed in regard to some or all of
the specification contained in this document. For more information,
see http://www.ietf.org/ietf/IPR/tellabs-ipr-draft-shiomoto-ccamp-
gmpls-mrn-reqs.txt
10. Full Copyright Statement
Copyright (C) The Internet Society (2006). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.
This document and the information contained herein are provided on
an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT
THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR
ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE.