draft-ietf-ccamp-rwa-info-05.txt   draft-ietf-ccamp-rwa-info-06.txt 
Network Working Group Y. Lee Network Working Group Y. Lee
Internet Draft Huawei Internet Draft Huawei
Intended status: Informational G. Bernstein Intended status: Informational G. Bernstein
Expires: April 2010 Grotto Networking Expires: August 2010 Grotto Networking
D. Li D. Li
Huawei Huawei
W. Imajuku W. Imajuku
NTT NTT
October 9, 2009 February 8, 2010
Routing and Wavelength Assignment Information Model for Wavelength Routing and Wavelength Assignment Information Model for Wavelength
Switched Optical Networks Switched Optical Networks
draft-ietf-ccamp-rwa-info-05.txt draft-ietf-ccamp-rwa-info-06.txt
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Abstract Abstract
This document provides a model of information needed by the routing This document provides a model of information needed by the routing
and wavelength assignment (RWA) process in wavelength switched and wavelength assignment (RWA) process in wavelength switched
optical networks (WSONs). The purpose of the information described optical networks (WSONs). The purpose of the information described
in this model is to facilitate constrained lightpath computation in in this model is to facilitate constrained lightpath computation in
WSONs, particularly in cases where there are no or a limited number WSONs. This model takes into account compatibility constraints
of wavelength converters available. This model does not include between WSON signal attributes and network elements but does not
optical impairments. include constraints due to optical impairments. Aspects of this
information that may be of use to other technologies utilizing a
GMPLS control plane are discussed.
Table of Contents Table of Contents
1. Introduction...................................................3 1. Introduction...................................................3
1.1. Revision History..........................................3 1.1. Revision History..........................................4
1.1.1. Changes from 01......................................3 1.1.1. Changes from 01......................................4
1.1.2. Changes from 02......................................3 1.1.2. Changes from 02......................................4
1.1.3. Changes from 03......................................4 1.1.3. Changes from 03......................................4
1.1.4. Changes from 04......................................4 1.1.4. Changes from 04......................................4
2. Terminology....................................................4 1.1.5. Changes from 05......................................5
2. Terminology....................................................5
3. Routing and Wavelength Assignment Information Model............5 3. Routing and Wavelength Assignment Information Model............5
3.1. Dynamic and Relatively Static Information.................5 3.1. Dynamic and Relatively Static Information.................6
3.2. Node Information..........................................6 4. Node Information (General).....................................6
3.2.1. Connectivity Matrix..................................6 4.1. Connectivity Matrix.......................................7
3.2.2. Shared Risk Node Group...............................7 4.2. Shared Risk Node Group....................................8
3.2.3. Wavelength Converter Pool............................7 5. Node Information (WSON specific)...............................8
3.2.4. OEO Wavelength Converter Info.......................10 5.1. Resource Accessibility/Availability.......................9
3.3. Link Information.........................................10 5.2. Resource Signal Constraints and Processing Capabilities..11
3.3.1. Administrative Group................................10 5.3. Compatibility and Capability Details.....................11
3.3.2. Interface Switching Capability Descriptor...........11 5.3.1. Modulation Type List................................11
3.3.3. Link Protection Type (for this link)................11 5.3.2. FEC Type List.......................................12
3.3.4. Shared Risk Link Group Information..................11 5.3.3. Bit Rate Range List.................................12
3.3.5. Traffic Engineering Metric..........................11 5.3.4. Acceptable Client Signal List.......................12
3.3.6. Port Wavelength (label) Restrictions................11 5.3.5. Processing Capability List..........................12
3.4. Dynamic Link Information.................................13 6. Link Information (General)....................................13
3.5. Dynamic Node Information.................................13 6.1. Administrative Group.....................................13
4. Security Considerations.......................................14 6.2. Interface Switching Capability Descriptor................13
5. IANA Considerations...........................................14 6.3. Link Protection Type (for this link).....................14
6. Acknowledgments...............................................14 6.4. Shared Risk Link Group Information.......................14
7. References....................................................15 6.5. Traffic Engineering Metric...............................14
7.1. Normative References.....................................15 6.6. Port Label (Wavelength) Restrictions.....................14
7.2. Informative References...................................15 7. Dynamic Components of the Information Model...................16
8. Contributors..................................................16 7.1. Dynamic Link Information (General).......................16
Author's Addresses...............................................17 7.2. Dynamic Node Information (WSON Specific).................16
Intellectual Property Statement..................................17 8. Security Considerations.......................................17
Disclaimer of Validity...........................................18 9. IANA Considerations...........................................17
10. Acknowledgments..............................................17
11. References...................................................18
11.1. Normative References....................................18
11.2. Informative References..................................19
12. Contributors.................................................20
Author's Addresses...............................................20
Intellectual Property Statement..................................21
Disclaimer of Validity...........................................22
1. Introduction 1. Introduction
The purpose of the following information model for WSONs is to The purpose of the following information model for WSONs is to
facilitate constrained lightpath computation and as such is not a facilitate constrained lightpath computation and as such is not a
general purpose network management information model. In particular general purpose network management information model. This constraint
this model has particular value in the cases where there are no or a is frequently referred to as the "wavelength continuity" constraint,
limited number of wavelength converters available in the WSON. This and the corresponding constrained lightpath computation is known as
constraint is frequently referred to as the "wavelength continuity" the routing and wavelength assignment (RWA) problem. Hence the
constraint, and the corresponding constrained lightpath computation information model must provide sufficient topology and wavelength
is known as the routing and wavelength assignment (RWA) problem. restriction and availability information to support this computation.
Hence the information model must provide sufficient topology and More details on the RWA process and WSON subsystems and their
wavelength restriction and availability information to support this properties can be found in [WSON-Frame]. The model defined here
computation. More details on the RWA process and WSON subsystems and includes constraints between WSON signal attributes and network
their properties can be found in [WSON-Frame]. The model defined here elements, but does not include optical impairments.
does not currently include impairments however optical impairments
can be accommodated by the general framework presented here.
1.1. Revision History In addition to presenting an information model suitable for path
computation in WSON, this document also highlights model aspects that
may have general applicability to other technologies utilizing a
GMPLS control plane. We refer to the information model applicable to
other technologies beyond WSON as "general" to distinguish from the
"WSON-specific" model that is applicable only to WSON technology.
1.1. Revision History
1.1.1. Changes from 01 1.1.1. Changes from 01
Added text on multiple fixed and switched connectivity matrices. Added text on multiple fixed and switched connectivity matrices.
Added text on the relationship between SRNG and SRLG and encoding Added text on the relationship between SRNG and SRLG and encoding
considerations. considerations.
Added clarifying text on the meaning and use of port/wavelength Added clarifying text on the meaning and use of port/wavelength
restrictions. restrictions.
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1.1.3. Changes from 03 1.1.3. Changes from 03
Removed signal related text from section 3.2.4 as signal related Removed signal related text from section 3.2.4 as signal related
information is deferred to a new signal compatibility draft. information is deferred to a new signal compatibility draft.
Removed encoding specific text from Section 3.3.1 of version 03. Removed encoding specific text from Section 3.3.1 of version 03.
1.1.4. Changes from 04 1.1.4. Changes from 04
Removed encoding specific text from Section 3.2.1. Removed encoding specific text from Section 4.1.
Removed encoding specific text from Section 3.4. Removed encoding specific text from Section 3.4.
1.1.5. Changes from 05
Renumbered sections for clarity.
Updated abstract and introduction to encompass signal
compatibility/generalization.
Generalized Section on wavelength converter pools to include electro
optical subsystems in general. This is where we added signal
compatibility modeling.
2. Terminology 2. Terminology
CWDM: Coarse Wavelength Division Multiplexing. CWDM: Coarse Wavelength Division Multiplexing.
DWDM: Dense Wavelength Division Multiplexing. DWDM: Dense Wavelength Division Multiplexing.
FOADM: Fixed Optical Add/Drop Multiplexer. FOADM: Fixed Optical Add/Drop Multiplexer.
ROADM: Reconfigurable Optical Add/Drop Multiplexer. A reduced port ROADM: Reconfigurable Optical Add/Drop Multiplexer. A reduced port
count wavelength selective switching element featuring ingress and count wavelength selective switching element featuring ingress and
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o Link Information o Link Information
o Dynamic Node Information o Dynamic Node Information
o Dynamic Link Information o Dynamic Link Information
Note that this is roughly the categorization used in [G.7715] section Note that this is roughly the categorization used in [G.7715] section
7. 7.
In the following we use where applicable the reduced Backus-Naur form In the following we use, where applicable, the reduced Backus-Naur
(RBNF) syntax of [RBNF] to aid in defining the RWA information model. form (RBNF) syntax of [RBNF] to aid in defining the RWA information
model.
3.1. Dynamic and Relatively Static Information 3.1. Dynamic and Relatively Static Information
All the RWA information of concern in a WSON network is subject to All the RWA information of concern in a WSON network is subject to
change over time. Equipment can be upgraded; links may be placed in change over time. Equipment can be upgraded; links may be placed in
or out of service and the like. However, from the point of view of or out of service and the like. However, from the point of view of
RWA computations there is a difference between information that can RWA computations there is a difference between information that can
change with each successive connection establishment in the network change with each successive connection establishment in the network
and that information that is relatively static on the time scales of and that information that is relatively static on the time scales of
connection establishment. A key example of the former is link connection establishment. A key example of the former is link
wavelength usage since this can change with connection setup/teardown wavelength usage since this can change with connection setup/teardown
and this information is a key input to the RWA process. Examples of and this information is a key input to the RWA process. Examples of
relatively static information are the potential port connectivity of relatively static information are the potential port connectivity of
a WDM ROADM, and the channel spacing on a WDM link. a WDM ROADM, and the channel spacing on a WDM link.
In this document we will separate, where possible, dynamic and static In this document we will separate, where possible, dynamic and static
information so that these can be kept separate in possible encodings information so that these can be kept separate in possible encodings
and hence allowing for separate updates of these two types of and hence allowing for separate updates of these two types of
information thereby reducing processing and traffic load caused by information thereby reducing processing and traffic load caused by
the timely distribution of the more dynamic RWA WSON information. the timely distribution of the more dynamic RWA WSON information.
3.2. Node Information 4. Node Information (General)
The node information described here contains the relatively static The node information described here contains the relatively static
information related to a WSON node. This includes connectivity information related to a WSON node. This includes connectivity
constraints amongst ports and wavelengths since WSON switches can constraints amongst ports and wavelengths since WSON switches can
exhibit asymmetric switching properties. Additional information could exhibit asymmetric switching properties. Additional information could
include properties of wavelength converters in the node if any are include properties of wavelength converters in the node if any are
present. In [Switch] it was shown that the wavelength connectivity present. In [Switch] it was shown that the wavelength connectivity
constraints for a large class of practical WSON devices can be constraints for a large class of practical WSON devices can be
modeled via switched and fixed connectivity matrices along with modeled via switched and fixed connectivity matrices along with
corresponding switched and fixed port constraints. We include these corresponding switched and fixed port constraints. We include these
connectivity matrices with our node information the switched and connectivity matrices with our node information the switched and
fixed port wavelength constraints with the link information. fixed port wavelength constraints with the link information.
Formally, Formally,
<Node_Information> ::= <Node_ID> [<ConnectivityMatrix>...] <Node_Information> ::= <Node_ID> [<ConnectivityMatrix>...]
[<WavelengthConverterPool>]
Where the Node_ID would be an appropriate identifier for the node Where the Node_ID would be an appropriate identifier for the node
within the WSON RWA context. within the WSON RWA context.
Note that multiple connectivity matrices are allowed and hence can Note that multiple connectivity matrices are allowed and hence can
fully support the most general cases enumerated in [Switch]. fully support the most general cases enumerated in [Switch].
3.2.1. Connectivity Matrix 4.1. Connectivity Matrix
The connectivity matrix (ConnectivityMatrix) represents either the The connectivity matrix (ConnectivityMatrix) represents either the
potential connectivity matrix for asymmetric switches (e.g. ROADMs potential connectivity matrix for asymmetric switches (e.g. ROADMs
and such) or fixed connectivity for an asymmetric device such as a and such) or fixed connectivity for an asymmetric device such as a
multiplexer. Note that this matrix does not represent any particular multiplexer. Note that this matrix does not represent any particular
internal blocking behavior but indicates which ingress ports and internal blocking behavior but indicates which ingress ports and
wavelengths could possibly be connected to a particular output port. wavelengths could possibly be connected to a particular output port.
Representing internal state dependent blocking for a switch or ROADM Representing internal state dependent blocking for a switch or ROADM
is beyond the scope of this document and due to it's highly is beyond the scope of this document and due to it's highly
implementation dependent nature would not be subject to implementation dependent nature would most likely not be subject to
standardization. This is a conceptual M by N matrix representing the standardization in the future. The connectivity matrix is a
potential switched or fixed connectivity, where M represents the conceptual M by N matrix representing the potential switched or fixed
number of ingress ports and N the number of egress ports. We say this connectivity, where M represents the number of ingress ports and N
is a "conceptual" since this matrix tends to exhibit structure that the number of egress ports. We say this is a "conceptual" matrix
allows for very compact representations that are useful for both since this matrix tends to exhibit structure that allows for very
transmission and path computation [Encode]. compact representations that are useful for both transmission and
path computation [Encode].
Note that the connectivity matrix concept can be useful in any Note that the connectivity matrix information element can be useful
context where asymmetric switches are utilized. in any technology context where asymmetric switches are utilized.
ConnectivityMatrix(i, j) ::= <MatrixID> <ConnType> <Matrix> ConnectivityMatrix(i, j) ::= <MatrixID> <ConnType> <Matrix>
Where Where
<MatrixID> is a unique identifier for the matrix. <MatrixID> is a unique identifier for the matrix.
<ConnType> can be either 0 or 1 depending upon whether the <ConnType> can be either 0 or 1 depending upon whether the
connectivity is either fixed or potentially switched. connectivity is either fixed or potentially switched.
<Matrix> represents the fixed or switched connectivity in that <Matrix> represents the fixed or switched connectivity in that
Matrix(i, j) = 0 or 1 depending on whether ingress port i can connect Matrix(i, j) = 0 or 1 depending on whether ingress port i can connect
to egress port j for one or more wavelengths. to egress port j for one or more wavelengths.
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<MatrixID> is a unique identifier for the matrix. <MatrixID> is a unique identifier for the matrix.
<ConnType> can be either 0 or 1 depending upon whether the <ConnType> can be either 0 or 1 depending upon whether the
connectivity is either fixed or potentially switched. connectivity is either fixed or potentially switched.
<Matrix> represents the fixed or switched connectivity in that <Matrix> represents the fixed or switched connectivity in that
Matrix(i, j) = 0 or 1 depending on whether ingress port i can connect Matrix(i, j) = 0 or 1 depending on whether ingress port i can connect
to egress port j for one or more wavelengths. to egress port j for one or more wavelengths.
3.2.2. Shared Risk Node Group 4.2. Shared Risk Node Group
SRNG: Shared risk group for nodes. The concept of a shared risk link SRNG: Shared risk group for nodes. The concept of a shared risk link
group was defined in [RFC4202]. This can be used to achieve a desired group was defined in [RFC4202]. This can be used to achieve a desired
"amount" of link diversity. It is also desirable to have a similar "amount" of link diversity. It is also desirable to have a similar
capability to achieve various degrees of node diversity. This is capability to achieve various degrees of node diversity. This is
explained in [G.7715]. Typical risk groupings for nodes can include explained in [G.7715]. Typical risk groupings for nodes can include
those nodes in the same building, within the same city, or geographic those nodes in the same building, within the same city, or geographic
region. region.
Since the failure of a node implies the failure of all links Since the failure of a node implies the failure of all links
associated with that node a sufficiently general shared risk link associated with that node a sufficiently general shared risk link
group (SRLG) encoding, such as that used in GMPLS routing extensions group (SRLG) encoding, such as that used in GMPLS routing extensions
can explicitly incorporate SRNG information. can explicitly incorporate SRNG information.
3.2.3. Wavelength Converter Pool 5. Node Information (WSON specific)
A WSON node may include wavelength converters. These are usually As discussed in [WSON-Frame] a WSON node may contain electro-optical
arranged into some type of pool to promote resource sharing. There subsystems such as regenerators, wavelength converters or entire
are a number of different approaches used in the design of switches switching subsystems. The model present here can be used in
with converter pools. However, from the point of view of path characterizing the accessibility and availability of limited
computation we need to know the following: resources such as regenerators or wavelength converters as well as
WSON signal attribute constraints of electro-optical subsystems. As
such this information element is fairly specific to WSON
technologies. We refer to regenerator block or wavelength converter
block as resource block.
1. The nodes that support wavelength conversion. A WSON node may include regenerators or wavelength converters
arranged in a shared pool. As discussed in [WSON-Frame] this can
include OEO based WDM switches as well. There are a number of
different approaches used in the design of WDM switches containing
regenerator or converter pools. However, from the point of view of
path computation we need to know the following:
1. The nodes that support regeneration or wavelength conversion.
2. The accessibility and availability of a wavelength converter to 2. The accessibility and availability of a wavelength converter to
convert from a given ingress wavelength on a particular ingress convert from a given ingress wavelength on a particular ingress
port to a desired egress wavelength on a particular egress port. port to a desired egress wavelength on a particular egress port.
3. Limitations on the types of signals that can be converted and the 3. Limitations on the types of signals that can be converted and the
conversions that can be performed. conversions that can be performed.
To model point 2 above we can use a similar technique as used to <Node_Information> ::= <Node_ID> [<ConnectivityMatrix>...]
model ROADMs and optical switches this technique was generally [<ResourcePool>] [<ResourceProperties>]
discussed in [WSON-Frame] and consisted of a matrix to indicate 5.1. Resource Accessibility/Availability
possible connectivity along with wavelength constraints for
links/ports. Since wavelength converters are considered a scarce
resource we will also want to our model to include as a minimum the
usage state of individual wavelength converters in the pool. Models
that incorporate more state to further reveal blocking conditions on
ingress or egress to particular converters are for further study.
We utilize a three stage model as shown schematically in Figure 1. In A similar technique as used to model ROADMs and optical switches can
this model we assume N ingress ports (fibers), P wavelength be used to model regenerator/converter accessibility. This technique
converters, and M egress ports (fibers). Since not all ingress ports was generally discussed in [WSON-Frame] and consisted of a matrix to
can necessarily reach the converter pool, the model starts with a indicate possible connectivity along with wavelength constraints for
wavelength pool ingress matrix WI(i,p) = {0,1} whether ingress port i links/ports. Since regenerators or wavelength converters may be
can reach potentially reach wavelength converter p. considered a scarce resource we will also want to our model to
include as a minimum the usage state (availability) of individual
regenerators or converters in the pool. Models that incorporate more
state to further reveal blocking conditions on ingress or egress to
particular converters are for further study and not included here.
Since not all wavelengths can necessarily reach all the converters or The three stage model as shown schematically in Figure 1. In this
the converters may have limited input wavelength range we have a set model we assume N ingress ports (fibers), P resource blocks
of ingress port constraints for each wavelength converter. Currently containing one or more identical resources (e.g. wavelength
we assume that a wavelength converter can only take a single converters), and M egress ports (fibers). Since not all ingress ports
wavelength on input. We can model each wavelength converter ingress can necessarily reach each resource block, the model starts with a
port constraint via a wavelength set mechanism. resource pool ingress matrix RI(i,p) = {0,1} whether ingress port i
can reach potentially reach resource block p.
Next we have a state vector WC(j) = {0,1} dependent upon whether Since not all wavelengths can necessarily reach all the resources or
wavelength converter j in the pool is in use. This is the only state the resources may have limited input wavelength range we have a set
kept in the converter pool model. This state is not necessary for of ingress port constraints for each resource. Currently we assume
modeling "fixed" transponder system, i.e., systems where there is no that a resource with a resource block can only take a single
sharing. In addition, this state information may be encoded in a wavelength on input. We can model each resource block ingress port
much more compact form depending on the overall connectivity constraint via a wavelength set mechanism.
structure [WC-Pool].
After that, we have a set of wavelength converter egress wavelength Next we have a state vector RA(j) = {0,...,k} which tells us the
constraints. These constraints indicate what wavelengths a particular number of resources in resource block j in use. This is the only
wavelength converter can generate or are restricted to generating due state kept in the resource pool model. This state is not necessary
to internal switch structure. for modeling "fixed" transponder system or full OEO switches with WDM
interfaces, i.e., systems where there is no sharing.
Finally, we have a wavelength pool egress matrix WE(p,k) = {0,1} After that, we have a set of resource egress wavelength constraints.
depending on whether the output from wavelength converter p can reach These constraints indicate what wavelengths a particular resource
block can generate or are restricted to generating e.g., a fixed
regenerator would be limited to a single lambda.
Finally, we have a resource pool egress matrix RE(p,k) = {0,1}
depending on whether the output from resource block p can reach
egress port k. Examples of this method being used to model wavelength egress port k. Examples of this method being used to model wavelength
converter pools for several switch architectures from the literature converter pools for several switch architectures from the literature
are given in reference [WC-Pool]. are given in reference [WC-Pool].
I1 +-------------+ +-------------+ E1 I1 +-------------+ +-------------+ E1
----->| | +--------+ | |-----> ----->| | +--------+ | |----->
I2 | +------+ WC #1 +-------+ | E2 I2 | +------+ Rb #1 +-------+ | E2
----->| | +--------+ | |-----> ----->| | +--------+ | |----->
| Wavelength | | Wavelength | | | | |
| Converter | +--------+ | Converter | | Resource | +--------+ | Resource |
| Pool +------+ WC #2 +-------+ Pool | | Pool +------+ +-------+ Pool |
| | +--------+ | | | | + Rb #2 + | |
| Ingress | | Egress | | Ingress +------+ +-------| Egress |
| Connection | . | Connection | | Connection | +--------+ | Connection |
| Matrix | . | Matrix | | Matrix | . | Matrix |
| | . | | | | . | |
| | | | | | . | |
IN | | +--------+ | | EM IN | | +--------+ | | EM
----->| +------+ WC #P +-------+ |-----> ----->| +------+ Rb #P +-------+ |----->
| | +--------+ | | | | +--------+ | |
+-------------+ ^ ^ +-------------+ +-------------+ ^ ^ +-------------+
| | | |
| | | |
| | | |
| | | |
Ingress wavelength Egress wavelength Ingress wavelength Egress wavelength
constraints for constraints for constraints for constraints for
each converter each converter each resource each resource
Figure 1 Schematic diagram of wavelength converter pool model. Figure 1 Schematic diagram of resource pool model.
Formally we can specify the model as: Formally we can specify the model as:
<WavelengthConverterPool> ::= <PoolIngressMatrix> <ResourcePool> ::= <ResourceBlockInfo><PoolIngressMatrix>
<IngressPoolConstraints> [<WCPoolState>] <EgressPoolConstraints> <IngressWaveConstraints> [<ResourcePoolState>]
<PoolEgressMatrix> <EgressWaveConstraints> <PoolEgressMatrix>
Note that except for <WCPoolState> all the other components of
<WavelengthConverterPool> are relatively static. In addition
<WCPoolState> is a relatively small structure compared potentially to
the others and hence in a future revision of this document maybe
moved to a new section on dynamic node information.
3.2.4. OEO Wavelength Converter Info Where
An OEO based wavelength converter can be characterized by an input <ResourceBlockInfo>:=(<ResourceBlockID><ResourceBlockSize>)...
wavelength set and an output wavelength set. Such a wavelength
converter can be modeled by:
<OEOWavelengthConverterInfo> ::= [<InputWavelengthSet>] <ResourcePoolState>:=(<ResourceBlockID><NumResourcesInUse>)...
[<OutputWavelengthSet>]
3.3. Link Information Note that except for <ResourcePoolState> all the other components of
<ResourcePool> are relatively static.
5.2. Resource Signal Constraints and Processing Capabilities
The wavelength conversion abilities of a resource (e.g. regenerator,
wavelength converter) were modeled in the <EgressWaveConstraints>
previously discussed. As discussed in [WSON-Frame] we can model the
constraints on an electro-optical resource in terms of input
constraints, processing capabilities, and output constraints:
<ResourceProperties> ::=
([<ResourceSet>]<InputConstraints><ProcessingCapabilities><OutputCons
traints>)*
Where <ResourceSet> is a list of resource block identifiers with the
same characteristics. If this set is missing the constraints are
applied to the entire network element.
The <InputConstraints> are signal compatibility based constraints.
The details of these constraints are defined in section 5.3.
<InputConstraints> ::=
<ModulationTypeList><FECTypeList><BitRateRange><ClientSignalList>
The <ProcessingCapabilities> are important operations that the
resource (or network element) can perform on the signal. The details
of these capabilities are defined in section 5.3.
<ProcessingCapabilities> ::=
<RegenerationCapabilities><FaultPerfMon><VendorSpecific>
The <OutputConstraints> are either restrictions on the properties of
the signal leaving the resource or network element or options
concerning the signal properties when leaving the resource or network
element.
<OutputConstraints> := <ModulationTypeList><FECTypeList>
5.3. Compatibility and Capability Details
5.3.1. Modulation Type List
Modulation type, also known as optical tributary signal class,
comes in two distinct flavors: (i) ITU-T standardized types; (ii)
vendor specific types. The permitted modulation type list can
include any mixture of standardized and vendor specific types.
<modulation-list>::=
[<STANDARD_MODULATION>|<VENDOR_MODULATION>]...
Where the STANDARD_MODULATION object just represents one of the
ITU-T standardized optical tributary signal class and the
VENDOR_MODULATION object identifies one vendor specific modulation
type.
5.3.2. FEC Type List
Some devices can handle more than one FEC type and hence a list is
needed.
<fec-list>::= [<FEC>]
Where the FEC object represents one of the ITU-T standardized FECs
defined in [G.709], [G.707], [G.975.1] or a vendor-specific FEC.
5.3.3. Bit Rate Range List
Some devices can handle more than one particular bit rate range
and hence a list is needed.
<rate-range-list>::= [<rate-range>]...
<rate-range>::=<START_RATE><END_RATE>
Where the START_RATE object represents the lower end of the range
and the END_RATE object represents the higher end of the range.
5.3.4. Acceptable Client Signal List
The list is simply:
<client-signal-list>::=[<GPID>]...
Where the Generalized Protocol Identifiers (GPID) object
represents one of the IETF standardized GPID values as defined in
[RFC3471] and [RFC4328].
5.3.5. Processing Capability List
We have defined ProcessingCapabilities in Section 5.2 as follows:
<ProcessingCapabilities> ::=
<RegenerationCapabilities><FaultPerfMon><VendorSpecific>
The processing capability list sub-TLV is a list of processing
functions that the WSON network element (NE) can perform on the
signal including:
1. Regeneration capability
2. Fault and performance monitoring
3. Vendor Specific capability
Note that the code points for Fault and performance monitoring and
vendor specific capability are subject to further study.
6. Link Information (General)
MPLS-TE routing protocol extensions for OSPF and IS-IS [RFC3630], MPLS-TE routing protocol extensions for OSPF and IS-IS [RFC3630],
[RFC5305] along with GMPLS routing protocol extensions for OSPF and [RFC5305] along with GMPLS routing protocol extensions for OSPF and
IS-IS [RFC4203, RFC5307] provide the bulk of the relatively static IS-IS [RFC4203, RFC5307] provide the bulk of the relatively static
link information needed by the RWA process. WSON networks bring in link information needed by the RWA process. However, WSON networks
additional link related constraints. These stem from WDM line system bring in additional link related constraints. These stem from WDM
characterization, laser transmitter tuning restrictions, and line system characterization, laser transmitter tuning restrictions,
switching subsystem port wavelength constraints, e.g., colored ROADM and switching subsystem port wavelength constraints, e.g., colored
drop ports. ROADM drop ports.
In the following summarize both information from existing route In the following summarize both information from existing GMPLS route
protocols and new information that maybe needed by the RWA process. protocols and new information that maybe needed by the RWA process.
<LinkInfo> ::= <LinkID> [<AdministrativeGroup>] [<InterfaceCapDesc>] <LinkInfo> ::= <LinkID> [<AdministrativeGroup>] [<InterfaceCapDesc>]
[<Protection>] [<SRLG>]... [<TrafficEngineeringMetric>] [<Protection>] [<SRLG>]... [<TrafficEngineeringMetric>]
[<PortWavelengthRestriction>] [<PortLabelRestriction>]
3.3.1. Administrative Group 6.1. Administrative Group
AdministrativeGroup: Defined in [RFC3630]. Each set bit corresponds AdministrativeGroup: Defined in [RFC3630]. Each set bit corresponds
to one administrative group assigned to the interface. A link may to one administrative group assigned to the interface. A link may
belong to multiple groups. This is a configured quantity and can be belong to multiple groups. This is a configured quantity and can be
used to influence routing decisions. used to influence routing decisions.
3.3.2. Interface Switching Capability Descriptor 6.2. Interface Switching Capability Descriptor
InterfaceSwCapDesc: Defined in [RFC4202], lets us know the different InterfaceSwCapDesc: Defined in [RFC4202], lets us know the different
switching capabilities on this GMPLS interface. In both [RFC4203] and switching capabilities on this GMPLS interface. In both [RFC4203] and
[RFC5307] this information gets combined with the maximum LSP [RFC5307] this information gets combined with the maximum LSP
bandwidth that can be used on this link at eight different priority bandwidth that can be used on this link at eight different priority
levels. levels.
3.3.3. Link Protection Type (for this link) 6.3. Link Protection Type (for this link)
Protection: Defined in [RFC4202] and implemented in [RFC4203, Protection: Defined in [RFC4202] and implemented in [RFC4203,
RFC5307]. Used to indicate what protection, if any, is guarding this RFC5307]. Used to indicate what protection, if any, is guarding this
link. link.
3.3.4. Shared Risk Link Group Information 6.4. Shared Risk Link Group Information
SRLG: Defined in [RFC4202] and implemented in [RFC4203, RFC5307]. SRLG: Defined in [RFC4202] and implemented in [RFC4203, RFC5307].
This allows for the grouping of links into shared risk groups, i.e., This allows for the grouping of links into shared risk groups, i.e.,
those links that are likely, for some reason, to fail at the same those links that are likely, for some reason, to fail at the same
time. time.
3.3.5. Traffic Engineering Metric 6.5. Traffic Engineering Metric
TrafficEngineeringMetric: Defined in [RFC3630]. This allows for the TrafficEngineeringMetric: Defined in [RFC3630]. This allows for the
definition of one additional link metric value for traffic definition of one additional link metric value for traffic
engineering separate from the IP link state routing protocols link engineering separate from the IP link state routing protocols link
metric. Note that multiple "link metric values" could find use in metric. Note that multiple "link metric values" could find use in
optical networks, however it would be more useful to the RWA process optical networks, however it would be more useful to the RWA process
to assign these specific meanings such as link mile metric, or to assign these specific meanings such as link mile metric, or
probability of failure metric, etc... probability of failure metric, etc...
3.3.6. Port Wavelength (label) Restrictions 6.6. Port Label (Wavelength) Restrictions
Port wavelength (label) restrictions (PortWavelengthRestriction) Port label (wavelength) restrictions (PortLabelRestriction) model the
model the wavelength (label) restrictions that the link and various label (wavelength) restrictions that the link and various optical
optical devices such as OXCs, ROADMs, and waveband multiplexers may devices such as OXCs, ROADMs, and waveband multiplexers may impose on
impose on a port. These restrictions tell us what wavelength may or a port. These restrictions tell us what wavelength may or may not be
may not be used on a link and are relatively static. This plays an used on a link and are relatively static. This plays an important
important role in fully characterizing a WSON switching device role in fully characterizing a WSON switching device [Switch]. Port
[Switch]. Port wavelength restrictions are specified relative to the wavelength restrictions are specified relative to the port in general
port in general or to a specific connectivity matrix (section 3.2.1. or to a specific connectivity matrix (section 4.1. Reference
Reference [Switch] gives an example where both switch and fixed [Switch] gives an example where both switch and fixed connectivity
connectivity matrices are used and both types of constraints occur on matrices are used and both types of constraints occur on the same
the same port. Such restrictions could be applied generally to other port. Such restrictions could be applied generally to other label
label types in GMPLS by adding new kinds of restrictions. types in GMPLS by adding new kinds of restrictions.
<PortWavelengthRestriction> ::= [<GeneralPortRestrictions>...] <PortLabelRestriction> ::= [<GeneralPortRestrictions>...]
[<MatrixSpecificRestrictions>...] [<MatrixSpecificRestrictions>...]
<GeneralPortRestrictions> ::= <RestrictionType> <GeneralPortRestrictions> ::= <RestrictionType>
[<RestrictionParameters>] [<RestrictionParameters>]
<MatrixSpecificRestriction> ::= <MatrixID> <RestrictionType> <MatrixSpecificRestriction> ::= <MatrixID> <RestrictionType>
[<RestrictionParameters>] [<RestrictionParameters>]
<RestrictionParameters> ::= [<WavelengthSet>...] [<MaxNumChannels>] <RestrictionParameters> ::= [<LabelSet>...] [<MaxNumChannels>]
[<MaxWaveBandWidth>] [<MaxWaveBandWidth>]
Where Where
MatrixID is the ID of the corresponding connectivity matrix (section MatrixID is the ID of the corresponding connectivity matrix (section
3.2.1. 4.1.
The RestrictionType parameter is used to specify general port The RestrictionType parameter is used to specify general port
restrictions and matrix specific restrictions. It can take the restrictions and matrix specific restrictions. It can take the
following values and meanings: following values and meanings:
SIMPLE_WAVELENGTH: Simple wavelength set restriction; The SIMPLE_WAVELENGTH: Simple wavelength set restriction; The
wavelength set parameter is required. wavelength set parameter is required.
CHANNEL_COUNT: The number of channels is restricted to be less than CHANNEL_COUNT: The number of channels is restricted to be less than
or equal to the Max number of channels parameter (which is required). or equal to the Max number of channels parameter (which is required).
skipping to change at page 12, line 41 skipping to change at page 15, line 38
of channels. Note that an additional wavelength set can be used to of channels. Note that an additional wavelength set can be used to
indicate the overall tuning range. Specific center frequency tuning indicate the overall tuning range. Specific center frequency tuning
information can be obtained from dynamic channel in use information. information can be obtained from dynamic channel in use information.
It is assumed that both center frequency and bandwidth (Q) tuning can It is assumed that both center frequency and bandwidth (Q) tuning can
be done without causing faults in existing signals. be done without causing faults in existing signals.
Restriction specific parameters are used with one or more of the Restriction specific parameters are used with one or more of the
previously listed restriction types. The currently defined parameters previously listed restriction types. The currently defined parameters
are: are:
WavelengthSet is a conceptual set of wavelengths (labels). LabelSet is a conceptual set of labels (wavelengths).
MaxNumChannels is the maximum number of channels that can be MaxNumChannels is the maximum number of channels that can be
simultaneously used (relative to either a port or a matrix). simultaneously used (relative to either a port or a matrix).
MaxWaveBandWidth is the maximum width of a tunable waveband switching MaxWaveBandWidth is the maximum width of a tunable waveband
device. switching device.
For example, if the port is a "colored" drop port of a ROADM then we For example, if the port is a "colored" drop port of a ROADM then we
have two restrictions: (a) CHANNEL_COUNT, with MaxNumChannels = 1, have two restrictions: (a) CHANNEL_COUNT, with MaxNumChannels = 1,
and (b) SIMPLE_WAVELENGTH, with the wavelength set consisting of a and (b) SIMPLE_WAVELENGTH, with the wavelength set consisting of a
single member corresponding to the frequency of the permitted single member corresponding to the frequency of the permitted
wavelength. See [Switch] for a complete waveband example. wavelength. See [Switch] for a complete waveband example.
This information model for port wavelength (label) restrictions is This information model for port wavelength (label) restrictions is
fairly general in that it can be applied to ports that have label fairly general in that it can be applied to ports that have label
restrictions only or to ports that are part of an asymmetric switch restrictions only or to ports that are part of an asymmetric switch
and have label restrictions. In addition, the types of label and have label restrictions. In addition, the types of label
restrictions that can be supported are extensible. restrictions that can be supported are extensible.
3.4. Dynamic Link Information 7. Dynamic Components of the Information Model
By dynamic information we mean information that is subject to change In the previously presented information model there are a limited
on a link with subsequent connection establishment or teardown. number of information elements that are dynamic, i.e., subject to
Currently for WSON the only information we currently envision is change with subsequent establishment and teardown of connections.
wavelength availability and wavelength in use for shared backup Depending on the protocol used to convey this overall information
purposes. model it may be possible to send this dynamic information separate
from the relatively larger amount of static information needed to
characterize WSON's and their network elements.
<DynamicLinkInfo> ::= <LinkID> <AvailableWavelengths> 7.1. Dynamic Link Information (General)
[<SharedBackupWavelengths>]
AvailableWavelengths is a set of wavelengths (labels) currently For WSON links wavelength availability and wavelengths in use for
available on the link. Given this information and the port wavelength shared backup purposes can be considered dynamic information and
hence we can isolate the dynamic information in the following set:
<DynamicLinkInfo> ::= <LinkID> <AvailableLabels>
[<SharedBackupLabels>]
AvailableLabels is a set of labels (wavelengths) currently available
on the link. Given this information and the port wavelength
restrictions we can also determine which wavelengths are currently in restrictions we can also determine which wavelengths are currently in
use. This parameter could potential be used with other technologies use. This parameter could potential be used with other technologies
that GMPLS currently covers or may cover in the future. that GMPLS currently covers or may cover in the future.
SharedBackupWavelengths is a set of wavelengths (labels)currently SharedBackupLabels is a set of labels (wavelengths)currently used for
used for shared backup protection on the link. An example usage of shared backup protection on the link. An example usage of this
this information in a WSON setting is given in [Shared]. This information in a WSON setting is given in [Shared]. This parameter
parameter could potential be used with other technologies that GMPLS could potential be used with other technologies that GMPLS currently
currently covers or may cover in the future. covers or may cover in the future.
3.5. Dynamic Node Information
Dynamic node information is used to hold information for a node that 7.2. Dynamic Node Information (WSON Specific)
can change frequently. Currently only wavelength converter pool
information is included as a possible (but not required) information
sub-element.
<DynamicNodeInfo> ::= <NodeID> [<WavelengthConverterPoolStatus>] Currently the only node information that can be considered dynamic is
the resource pool state and can be isolated into a dynamic node
information element as follows:
Where NodeID is a node identifier and the exact form of the <DynamicNodeInfo> ::= <NodeID> [<ResourcePoolState>]
wavelength converter pool status information is TBD.
4. Security Considerations 8. Security Considerations
This document discussed an information model for RWA computation in This document discussed an information model for RWA computation in
WSONs. Such a model is very similar from a security standpoint of the WSONs. Such a model is very similar from a security standpoint of the
information that can be currently conveyed via GMPLS routing information that can be currently conveyed via GMPLS routing
protocols. Such information includes network topology, link state protocols. Such information includes network topology, link state
and current utilization, and well as the capabilities of switches and and current utilization, and well as the capabilities of switches and
routers within the network. As such this information should be routers within the network. As such this information should be
protected from disclosure to unintended recipients. In addition, the protected from disclosure to unintended recipients. In addition, the
intentional modification of this information can significantly affect intentional modification of this information can significantly affect
network operations, particularly due to the large capacity of the network operations, particularly due to the large capacity of the
optical infrastructure to be controlled. optical infrastructure to be controlled.
5. IANA Considerations 9. IANA Considerations
This informational document does not make any requests for IANA This informational document does not make any requests for IANA
action. action.
6. Acknowledgments 10. Acknowledgments
This document was prepared using 2-Word-v2.0.template.dot. This document was prepared using 2-Word-v2.0.template.dot.
7. References 11. References
7.1. Normative References 11.1. Normative References
[Encode] G. Bernstein, Y. Lee, D. Li, W. Imajuku, "Routing and [Encode] G. Bernstein, Y. Lee, D. Li, W. Imajuku, "Routing and
Wavelength Assignment Information Encoding for Wavelength Wavelength Assignment Information Encoding for Wavelength
Switched Optical Networks", work in progress: draft-ietf- Switched Optical Networks", work in progress: draft-ietf-
ccamp-rwa-wson-encode. ccamp-rwa-wson-encode.
[G.707] ITU-T Recommendation G.707, Network node interface for the
synchronous digital hierarchy (SDH), January 2007.
[G.709] ITU-T Recommendation G.709, Interfaces for the Optical
Transport Network(OTN), March 2003.
[G.975.1] ITU-T Recommendation G.975.1, Forward error correction for
high bit-rate DWDM submarine systems, February 2004.
[RBNF] A. Farrel, "Reduced Backus-Naur Form (RBNF) A Syntax Used in [RBNF] A. Farrel, "Reduced Backus-Naur Form (RBNF) A Syntax Used in
Various Protocol Specifications", RFC 5511, April 2009. Various Protocol Specifications", RFC 5511, April 2009.
[RFC3471] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Functional Description", RFC
3471, January 2003.
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630, September (TE) Extensions to OSPF Version 2", RFC 3630, September
2003. 2003.
[RFC4202] Kompella, K., Ed., and Y. Rekhter, Ed., "Routing Extensions [RFC4202] Kompella, K., Ed., and Y. Rekhter, Ed., "Routing Extensions
in Support of Generalized Multi-Protocol Label Switching in Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4202, October 2005 (GMPLS)", RFC 4202, October 2005
[RFC4203] Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions in [RFC4203] Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions in
Support of Generalized Multi-Protocol Label Switching Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4203, October 2005. (GMPLS)", RFC 4203, October 2005.
[RFC4328] Papadimitriou, D., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Extensions for G.709 Optical
Transport Networks Control", RFC 4328, January 2006.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, October 2008. Engineering", RFC 5305, October 2008.
[RFC5307] Kompella, K., Ed., and Y. Rekhter, Ed., "IS-IS Extensions [RFC5307] Kompella, K., Ed., and Y. Rekhter, Ed., "IS-IS Extensions
in Support of Generalized Multi-Protocol Label Switching in Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 5307, October 2008. (GMPLS)", RFC 5307, October 2008.
[WSON-Frame] Y. Lee, G. Bernstein, W. Imajuku, "Framework for GMPLS [WSON-Frame] Y. Lee, G. Bernstein, W. Imajuku, "Framework for GMPLS
and PCE Control of Wavelength Switched Optical Networks", and PCE Control of Wavelength Switched Optical Networks",
work in progress: draft-ietf-ccamp-rwa-wson-framework. work in progress: draft-ietf-ccamp-rwa-wson-framework.
7.2. Informative References 11.2. Informative References
[Shared] G. Bernstein, Y. Lee, "Shared Backup Mesh Protection in PCE- [Shared] G. Bernstein, Y. Lee, "Shared Backup Mesh Protection in PCE-
based WSON Networks", iPOP 2008, http://www.grotto- based WSON Networks", iPOP 2008, http://www.grotto-
networking.com/wson/iPOP2008_WSON-shared-mesh-poster.pdf . networking.com/wson/iPOP2008_WSON-shared-mesh-poster.pdf .
[Switch] G. Bernstein, Y. Lee, A. Gavler, J. Martensson, " Modeling [Switch] G. Bernstein, Y. Lee, A. Gavler, J. Martensson, " Modeling
WDM Wavelength Switching Systems for Use in GMPLS and Automated WDM Wavelength Switching Systems for Use in GMPLS and Automated
Path Computation", Journal of Optical Communications and Path Computation", Journal of Optical Communications and
Networking, vol. 1, June, 2009, pp. 187-195. Networking, vol. 1, June, 2009, pp. 187-195.
[G.Sup39] ITU-T Series G Supplement 39, Optical system design and [G.Sup39] ITU-T Series G Supplement 39, Optical system design and
engineering considerations, February 2006. engineering considerations, February 2006.
[WC-Pool] G. Bernstein, Y. Lee, "Modeling WDM Switching Systems [WC-Pool] G. Bernstein, Y. Lee, "Modeling WDM Switching Systems
including Wavelength Converters" to appear www.grotto- including Wavelength Converters" to appear www.grotto-
networking.com, 2008. networking.com, 2008.
8. Contributors 12. Contributors
Diego Caviglia Diego Caviglia
Ericsson Ericsson
Via A. Negrone 1/A 16153 Via A. Negrone 1/A 16153
Genoa Italy Genoa Italy
Phone: +39 010 600 3736 Phone: +39 010 600 3736
Email: diego.caviglia@(marconi.com, ericsson.com) Email: diego.caviglia@(marconi.com, ericsson.com)
Anders Gavler Anders Gavler
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