Network Working Group Fatai Zhang
Internet-Draft Young Lee
Intended status: Informational Huawei
O. Gonzalez de Dios
Telefonica
Ramon Casellas
CTTC
D. Ceccarelli
Ericsson
Expires: September 05, 2012 March 05, 2012
Framework for GMPLS and PCE Control of Spectrum Switched
Optical Networks
draft-zhang-ccamp-sson-framework-00.txt
Status of this Memo
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Abstract
A new flexible grid of DWDM has been developed within the ITU-T
Study Group 15 to allow a more efficient spectrum allocation. In
such environment a data plane connection is switched based on the
allocated variable width optical spectrum frequency slot. This new
switching capability is referred to as Spectrum Switched Optical
Networks (SSON). This draft describes the framework for the
application of a GMPLS control plane to a SSON.
Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC-2119 [RFC2119].
Table of Contents
1. Introduction ................................................. 3
2. Terminology .................................................. 4
3. New characteristics of SSON .................................. 5
3.1. Overview of Flexible Grid .................................. 6
3.2. ROADM ...................................................... 7
3.3. Optical Transmitters and Receivers ......................... 8
4. Routing and Spectrum Assignment .............................. 9
4.1. Architectural Approaches to RSA ........................... 10
4.1.1. Combined RSA (R&SA) ..................................... 10
4.1.2. Separated RSA (R+SA) .................................... 11
4.1.3. Routing and Distributed SA (R+DSA) ...................... 11
5. Requirements for GMPLS Control Plane ........................ 11
5.1. Routing ................................................... 11
5.1.1. Available Frequency Ranges of DWDM Links ................ 12
5.1.2. Available Slot Width Ranges of DWDM Links ............... 12
5.1.3. Tunable Optical Transmitters and Receivers .............. 12
5.2. Signaling ................................................. 12
5.2.1. Slot Width Requirement .................................. 13
5.2.2. Frequency Slot Representation ........................... 13
5.3. PCE ....................................................... 13
5.3.1. RSA Computation Type .................................... 13
5.3.2. RSA path re-optimization request/reply .................. 14
5.3.3. Frequency Constraints ................................... 14
6. Security Considerations ..................................... 15
7. References .................................................. 15
7.1. Normative References ...................................... 15
7.2. Informative References .................................... 15
8. Authors' Addresses .......................................... 16
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1. Introduction
[G.694.1v1] defines the DWDM frequency grids for WDM applications. A
frequency grid is a reference set of frequencies used to denote
allowed nominal central frequencies that may be used for defining
applications. The channel spacing, i.e. the frequency spacing
between two allowed nominal central frequencies could be 12.5 GHz,
25 GHz, 50 GHz, 100 GHz or integer multiples of 100 GHz as defined
in [G.694.1v1]. The frequency spacing of the channels on a fiber is
fixed.
The data rate of optical signals becomes higher and higher with the
advancement of the optical technology. In the near future, it is
anticipated that high data rate signals (beyond 100 Gbit/s or even
400 Gbit/s) will be deployed in optical networks. These signals may
not be accommodated in the channel spacing specified in old
[G.694.1v1]. Moreover, ''mixed rate'' scenarios will be prevalent, and
the optical signals with different rates may require different
spectrum width. As a result, when the optical signals with different
rates are mixed to be transmitted on the same fiber, the frequency
allocation needs to be more flexible so as to improve spectral
efficiency.
An updated version of [G.694.1v1], i.e., [G.FLEXIGRID] has been
consented in December 2011 in support of flexible grids. The terms
''frequency slot (the frequency range allocated to a channel and
unavailable to other channels within a flexible grid)'' and ''slot
width'' (the full width of a frequency slot in a flexible grid) are
introduced to address flexible grid extensions. A channel is
represented as a LSC (Lambda Switching Capable) LSP in the control
plane, and it means that a LSC LSP should occupy a frequency slot on
each fiber it traverses. In the case of flexible grid, different LSC
LSPs may have different slot widths on a fiber.
Thus the concept of Wavelength Switched Optical Network(WSON) is
extended to Spectrum Switched Optical Network (SSON) which includes
flexible capabilities (i.e. flexi-grid). In SSON, a data plane
connection is switched based on an optical spectrum frequency slot
of a variable (flexible) slot width, rather than based on a single
wavelength within a fixed grid and with a fixed channel spacing as
is the case for WSON. In this sense, a WSON can be seen as a
particular case of a SSON in which all slot widths are equal and
central frequencies depend on the used channel spacing.
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WSON related documents are currently being developed with the focus
of the GMPLS control of fixed grid optical networks. This document
describes the new characteristics of SSON and provides the framework
of GMPLS control for the new features of SSON beyond WSON.
Note that this document focuses on the general properties of SSON.
Information related to optical impairments is out of its scope and
will be addressed in a separate draft.
2. Terminology
Flexible Grid: a new WDM frequency grid defined with the aim of
allowing flexible optical spectrum management, in which the Slot
Width of the frequency ranges allocated to different channels are
flexible (variable size).
Frequency Range: a frequency range is defined as the portion of
frequency spectrum included between a lowest and a highest frequency.
Frequency Slot: the frequency range allocated to a slot and
unavailable to other slots within a flexible grid. A frequency slot
is defined by its nominal central frequency and its slot width.
Slot Width: the full width (in Hz) of a frequency slot. A slot width
can be expressed as a multiple (m) of a basic slot width (e.g. 12.5
GHz).
SSON: Spectrum-Switched Optical Network. An optical network in which
a data plane connection is switched based on an optical spectrum
frequency slot of a variable slot width, rather than based on a
fixed grid and fixed slot width. Please note that a Wavelength
Switched Optical Network (WSON) can be seen as a particular case of
SSON in which all slot widths are equal and depend on the used
channel spacing.
Flexi-LSP: a control plane construct that represents a data plane
connection in which the switching involves a frequency slot of a
variable (flexible) slot width. The mapped client signal is
transported over the frequency slot, using spectrum efficient
modulations such as Coherent Optical Orthogonal Frequency Division
Multiplexing (CO-OFDM) and Forward Error Correction (FEC) techniques.
Although still in the scope of LSC, the term flexi-LSP is used, when
needed, to differentiate from regular WSON LSP in which switching is
based on a nominal wavelength.
RSA: Routing and Spectrum Assignment. As opposed to the typical
Routing and Wavelength Assignment (RWA) problem of traditional WDM
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networks, the flexibility in SSON leads to spectral contiguous
constraint, which means that when assigning the spectral resources
to single connections, the resources assigned to them must be
contiguous over the entire connections in the spectrum domain. RSA
is introduced to describe the routing and spectrum assignment
procedures.
3. New characteristics of SSON
Wavelength Switched Optical Networks (WSONs) are constructed from
subsystems that include Wavelength Division Multiplexing (WDM) links,
tunable transmitters and receivers, Reconfigurable Optical Add/Drop
Multiplexers (ROADMs), wavelength converters, and electro-optical
network elements. WSON framework is described in [RFC6163]. The
introduced flexible grid brings some changes on GMPLS controlled
optical networks.
The concept of WSON is extended to SSON, to highlight that such
subsystems are extended with flexible capabilities (i.e. flexi-grid).
Note that, when modeling SSONs, a WSON can be seen as a particular
case of SSON where all LSC LSPs use a fixed (and equal) slot width
which depends on the used channel spacing.
In WSON, the joint determination of an optical path (physical route)
along with the nominal wavelength on a fiber is known as Routing and
Wavelength Assignment (RWA). Wavelength Assignment (WA) is the
determination of which wavelength can be used for a specific optical
path. In analogy with WSON, in SSON, the determination of a path and
a frequency slot (including both central frequency and slot width)
is referred to as Routing and Spectrum Assignment (RSA). Spectrum
Assignment (SA) is the process of determining the spectrum range
that can be used for one specific flex-LSP given a physical route.
Compared to WSON, flexibility needs to be introduced in optical
network devices such as ROADMs or optical transponders in order to
fully benefit from SSON (flexible grid) improved spectrum management.
Consequently, transceivers may be able to fully leverage flexible
optical channels with advanced modulation formats, and ROADMs may
need to be extended to allow flexible spectrum switching.
A flexible grid is defined for the DWDM system in [G.FLEXIGRID].
Compared to fixed grids a flexible grid has a smaller granularity
for the central frequencies and the slot width may range from say,
12.5 GHz to hundreds of GHz, in order to accommodate different
client data rates. The subsequent sections analyze the new
characteristics of flexible grid based on standard [G.FLEXIGRID],
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and then model ROADMs, and optical transponders in SSON with an
emphasis on those aspects that are of relevance to the control plane.
3.1. Overview of Flexible Grid
o Central Frequency
According to the definition of flexible DWDM grid in [G.FLEXIGRID],
the allowed nominal central frequencies are calculated as in the
case of flexible grid:
Central Frequency = 193.1 THz + n * 0.00625 THz
Where 193.1 THz is ITU-T ''anchor frequency'' for transmission over
the C band, n is a positive or negative integer including 0 and
0.00625 THz is the nominal central frequency granularity.
o Slot Width
A slot width is defined by:
12.5 GHz * m
Where m is a positive integer and 12.5 GHz is the slot width
granularity.
Note that, when flexi-grid is supported on a WDM link, the slot
width of different flexi-LSPs may be different.
The WDM link for flexible grid can be represented as shown in figure
1.
-9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11
...+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--...
^
193.1THz
Figure 1 Fiber link model for flexible grid
The symbol'+' represents the allowed nominal central frequencies.
The symbol ''--" represents the basic 6.25 GHz frequency slot. The
number on the top of the line represents the 'n' in the frequency
calculation formula. The nominal central frequency is 193.1 THz when
n equals zero.
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As Described in [G.FLEXIGRID], the flexible DWDM grid has a nominal
central frequency granularity of 6.25 GHz and a slot width
granularity of 12.5 GHz. However, devices or applications that make
use of the flexible grid, may not have to be capable of supporting
every possible slot width or central frequency granularity. For
example, ROADM and transceivers in SSON may support subset of all
possible slot width or posit defined in [G.FLEXIGRID].
3.2. ROADM
To support flexi grid, a ROADM is a key device which allows
spectrum-based optical switching. A classic degree-4 ROADM is shown
in Figure 2.
+-----------------------+
Line side-1 --->| |---> Line side-2
Input (I1) | | Output (E2)
Line side-1 <---| |<--- Line side-2
Output (E1) | | Input (I2)
| ROADM |
Line side-3 --->| |---> Line side-4
Input (I3) | | Output (E4)
Line side-3 <---| |<--- Line side-4
Output (E3) | | Input (I4)
| |
+-----------------------+
| O | O | O | O
| | | | | | | |
O | O | O | O |
Tributary Side: E5 I5 E6 I6 E7 I7 E8 I8
Figure 2 Degree-4 Bidirectional ROADM
The key feature of ROADMs is their highly asymmetric switching
capability which is described in [RFC6163] in detail. The asymmetric
switching feature of flexible ROADM in SSON is similar to fixed
ROADM in WSON. The ports on ROADM include line side port which is
connected to WDM link, tributary side input/output port which is
connected to transmitter/receiver. The main difference between
ROADMs in SSON and WSON is the capability of ports on ROADM, which
are characterized as follows:
From a SSON control plane perspective (in terms of path computation
and resource allocation), ROADMs line side ports are characterized
by the following aspects:
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o Available frequency ranges: the set or union of frequency ranges
that are not allocated (i.e. available or unused. The relative
grouping and distribution of available frequency ranges in a fiber
is usually referred to as ''fragmentation''.
o Available slot width ranges: the set or union of slot width ranges
supported by ROADM. It includes the following information:
o Slot width threshold: the minimum and maximum Slot Width
supported by ROADM. For example, the slot width can be from
50GHz to 200GHz.
o Step granularity: the minimum step by which the optical filter
bandwidth of ROADM can be increased or decreased. This
parameter is typically equal to slot width granularity defined
in [G.FLEXIGRID] (i.e. 12.5GHz) or integer multiples of 12.5GHz.
These properties can be injected into the link parameters from the
control plane perspective, which is described in Section 5.
Since the tributary side port is connected to a transmitter and
receiver, the characterization of tributary side ports is described
in the next section.
3.3. Optical Transmitters and Receivers
In WSON, the optical transmitter is the wavelength source and the
optical receiver is the wavelength sink of the WDM system. In each
direction, the wavelength used by the transmitter and receiver along
a path shall be consistent if no wavelength converter is available.
The central frequency used by a transmitter or receiver may be fixed
or tunable.
In SSON the optical spectrum (frequency slot width) used by
different flexi-LSPs may be variable. Optical transmitters/receivers
may have different restriction on the following properties:
o Available central frequencies: The set of central frequencies
which can be used by an optical transmitter/receiver.
o Slot width: The slot width needed by a transmitter/receiver.
The slot width is dependent on bit rate and modulation format. For
one specific transmitter, the bit rate and modulation format may
be tunable, so slot width would be determined by the modulation
format used at a given bit rate.
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Similarly, other information on transmitters and receivers
capabilities, in regard to signal processing is needed to perform
efficient RSA, much like in WSON [WSON-ENCODE].
4. Routing and Spectrum Assignment
A LSC flexi-LSP occupies a frequency slot, i.e. a range of
frequencies, on each link the LSP traverses.
Much like in WSON, in which if there is no (available) wavelength
converter in an optical network an LSP is subject to the ''wavelength
continuity constraint'' (see section 4 of [RFC6163]), in SSON if the
capability of shifting or converting the whole optical spectrum
allocated to a flex-LSP is not available, the flexi-LSP is subject
to the Optical ''Spectrum Continuity Constraint''.
Because of the limited availability of wavelength/spectrum
converters (sparse translucent optical network) the
wavelength/spectrum continuity constraint should always be
considered. When available, information regarding spectrum
conversion capabilities at the optical nodes may be used by RSA
mechanisms.
The RSA process determines a route and frequency slot for a flexi-
LSP. Note that the mapping between client signals data rates (10, 40,
100... Gbps) and optical slot widths (which are dependent on
modulation formats and other physical layer parameters) is out of
the scope of this document. The frequency slot can be deduced from
the central frequency and slot width parameters as follows:
Lowest frequency = (central frequency) - (slot width)/2;
Highest frequency = (central frequency) + (slot width)/2.
Hence, when a route is computed the spectrum assignment process (SA)
should determine the central frequency for a flexi-LSP based on the
slot width and available central frequencies information of the
transmitter and receiver, and the available frequency ranges
information and available slot width ranges of the links that the
route traverses.
Figure 2 shows two LSC LSPs that traverse a link.
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Frequency Slot 1 Frequency Slot 2
------------- -------------------
| | | |
-9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11
...+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--...
------------- -------------------
^ ^
Central F = 193.1THz Central F = 193.14375 THz
Slot width = 25 GHz Slot width = 37.5 GHz
Figure 2 Two LSC LSPs traverse a Link
The two wavelengths shown in figure 2 have the following meaning:
Flexi-LSP 1: central frequency = 193.1 THz, slot width = 25 GHz. It
means the frequency slot [193.0875 THz, 193.1125 THz] is assigned to
this LSC LSP.
Flexi-LSP 2: central frequency = 193.14375 THz, slot width = 37.5
GHz. It means the frequency slot [193.125 THz, 193.1625 THz] is
assigned to this LSC LSP.
Note that the frequency slots of two LSC flexi-LSPs on a fiber do
not overlap with each other, and a guard band may be considered to
counteract inter-channel detrimental effects.
4.1. Architectural Approaches to RSA
Similar to RWA for fixed grids, different ways of performing RSA in
conjunction with the control plane can be considered. The approaches
included in this document are provided for reference purposes only;
other possible options could also be deployed.
4.1.1. Combined RSA (R&SA)
In this case, a computation entity performs both routing and
frequency slot assignment. The computation entity should have the
detailed network information, e.g. connectivity topology constructed
by nodes/links information, available frequency ranges on each link,
node capability, etc.
The computation entity could reside on the following elements, which
depends on the implementation:
o PCE: PCE gets the detailed network information and implements the
RSA algorithm for RSA requests from the PCCs.
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o Ingress node: Ingress node gets the detailed network information
(e.g. through routing protocol) and implements the RSA algorithm
when a LSC LSP request is received.
4.1.2. Separated RSA (R+SA)
In this case, routing computation and frequency slot assignment are
performed by different entities. The first entity computes the
routes and provides them to the second entity; the second entity
assigns the frequency slot.
The first entity should get the connectivity topology to compute the
proper routes; the second entity should get the available frequency
ranges of the links and nodes' capabilities information to assign
the spectrum.
4.1.3. Routing and Distributed SA (R+DSA)
In this case, one entity computes the route but the frequency slot
assignment is performed hop-by-hop in a distributed way along the
route. The available central frequencies which meet the wavelength
continuity constraint should be collected hop by hop along the route.
This procedure can be implemented by the GMPLS signaling protocol.
The GMPLS signaling procedure is similar to the one described in
section 4.1.3 of [RFC6163] except that the label set should specify
the available central frequencies that meet the slot width
requirement of the LSC LSP, i.e. the frequency slot which is
determined by the central frequency and slot width MUST NOT overlap
with the existing LSC LSPs.
5. Requirements for GMPLS Control Plane
According to the different architecture approaches to RSA some
additional requirements have to be considered for the GMPLS control
of SSONs.
5.1. Routing
In the case of combined RSA architecture, the computation entity
needs to get the detailed network information, i.e. connectivity
topology, node capabilities and available frequency ranges of the
links. Route computation is performed based on the connectivity
topology and node capabilities; spectrum assignment is performed
based on the available frequency ranges of the links. The
computation entity may get the detailed network information by the
GMPLS routing protocol.
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Compared with [RFC6163], except wavelength-specific availability
information, the connectivity topology and node capabilities are the
same as WSON, which can be advertised by GMPLS routing protocol
(refer to section 6.2 of [RFC6163]. This section analyses the
necessary changes on link information brought by flexible grids.
5.1.1. Available Frequency Ranges of DWDM Links
In the case of flexible grids, channel central frequencies span from
193.1 THz towards both ends of the C band spectrum with 6.25 GHz
granularity. Different LSC LSPs could make use of different slot
widths on the same link. Hence, the available frequency ranges
should be advertised.
5.1.2. Available Slot Width Ranges of DWDM Links
The available slot width ranges needs to be advertised in order to
understand whether a LSC LSCP with a given slot width can be set up
or not.
Whether a LSC LSP with a certain slot width can be set up or not is
constrained by the available slot width ranges of flexible ROADM. So
the available slot width ranges should be advertised.
5.1.3. Tunable Optical Transmitters and Receivers
The slot width of a LSC LSP is determined by the transmitter and
receiver that could be mapped to ADD/DROP interfaces in WSON.
Moreover their central frequency could be fixed or tunable, hence,
both the slot width of an ADD/DROP interface and the available
central frequencies should be advertised.
5.2. Signaling
Compared with [RFC6163], except identifying the resource (i.e.,
fixed wavelength for WSON and frequency resource for flexible grids),
the other signaling requirements (e.g., unidirectional or
bidirectional, with or without converters) are the same as WSON
described in the section 6.1 of [RFC6163].
In the case of routing and distributed SA, GMPLS signaling can be
used to allocate the frequency slot to a LSC LSP. This brings the
following changes to the GMPLS signaling.
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5.2.1. Slot Width Requirement
In order to allocate a proper frequency slot for a LSC LSP, the
signaling should specify the slot width requirement of a LSC LSP.
Then the intermediate nodes can collect the acceptable central
frequencies that meet the slot width requirement hop by hop.
The tail-end node also needs to know the slot width of a LSC LSP to
assign the proper frequency resource. Hence, the slot width
requirement should be specified in the signaling message when a LSC
LSP is being set up.
5.2.2. Frequency Slot Representation
The frequency slot can be determined by the central frequency (n
value) and slot width (m value) as described in section 5. Such
parameters should be able to be specified by the signaling protocol.
5.3. PCE
[WSON-PCE] describes the architecture and requirements of PCE for
WSON. In the case of flexible grid, RSA instead of RWA is used for
routing and frequency slot assignment. Hence PCE should implement
RSA for flexible grids. The architecture and requirements of PCE for
flexible grids are similar to what is described in [WSON-PCE]. This
section describes the changes brought by flexible grids.
5.3.1. RSA Computation Type
A PCEP request within a PCReq message MUST be able to specify the
computation type of the request:
o Combined RSA: Both the route and frequency slot should be provided
by PCE.
o Routing Only: Only the route is requested to be provided by PCE.
The PCEP response within a PCRep Message MUST be able to specify the
route and the frequency slot assigned to the route.
RSA in SSON MAY include the check of signal processing capabilities,
which MAY be provided by the IGP. A PCC should be able to indicate
additional restrictions for such signal compatibility, either on the
endpoint or any given link (such as regeneration points).
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A PCC MUST be able to specify whether the PCE MUST also assign a
Modulation list and/or a FEC list, as defined in [WSON-ENCODE] and
[WSON-PCE].
A PCC MUST be able to specify whether the PCE MUST or SHOULD include
or exclude specific modulation formats and FEC mechanisms.
In the case where a valid path is not found, the response MUST be
able to specify the reason (e.g., no route, spectrum not found, etc.)
5.3.2. RSA path re-optimization request/reply
For a re-optimization request, the PCEP request MUST provide the
path to be re-optimized and include the following options:
o Re-optimize the path keeping the same frequency slot.
o Re-optimize spectrum keeping the same path.
o Re-optimize allowing both frequency slot and the path to change.
The corresponding PCEP response for the re-optimized request MUST
provide the Re-optimized path and frequency slot.
In case a path is not found, the response MUST include the reason
(e.g., no route, frequency slot not found, both of route and
frequency slot not found, etc.)
5.3.3. Frequency Constraints
A PCE should consider the following constraints brought by the
transmitters and receivers:
o Available central frequencies: The set of central frequencies that
can be used by an optical transmitter or receiver.
o Slot width: The slot width needed by a transmitter or receiver.
These constraints may be provided by the requester (PCC) in the PCEP
request or reside within the PCE's TEDB which stores the
transponder's capabilities.
A PCC may also specify the frequency constraints for policy reasons.
In this case, the constraints should be specified in the request
sent to the PCE. In any case, the PCE will compute the route and
assign the frequency slot to meet the constraints specified in
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theafore mentioned request and it will then return the result of the
path computation to the PCC in the corresponding response.
6. Security Considerations
This document does not introduce any further security issues other
than those described in [RFC6163] and [RFC5920].
7. References
7.1. Normative References
[RFC2119] S. Bradner, "Key words for use in RFCs to indicate
requirements levels", RFC 2119, March 1997.
[WSON-PCE] Y. Lee, G. Bernstein, Jonas Martensson, T. Takeda and T.
Tsuritani, "PCEP Requirements for WSON Routing and
Wavelength Assignment", draft-ietf-pce-wson-routing-
wavelength-05, July 2011.
[WSON-ENCODE] G. Bernstein, Y. Lee, Dan Li and W. Imajuku, "Routing
and Wavelength Assignment Information Encoding for
Wavelength Switched Optical Networks", draft-ietf-ccamp-
rwa-wson-encode, August 2011.
[RFC6163] Y. Lee, G. Bernstein and W. Imajuku, "Framework for GMPLS
and Path Computation Element (PCE) Control of Wavelength
Switched Optical Networks (WSONs)", RFC 6163, April 2011.
[G.FLEXIGRID]Draft revised G.694.1 version 1.6, Consented in
December 2011, ITU-T Study Group 15.
7.2. Informative References
[G.694.1v1]ITU-T Recommendation G.694.1, Spectral grids for WDM
applications: DWDM frequency grid, June 2002.
[RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, July 2010.
[SSON-RSA]Yawei Yin, Ke Wen, David J. Geisler, Ruiting Liu, and S. J.
B. Yoo, ''Dynamic on-demand defragmentation in flexible
bandwidth elastic optical networks'', 2012 Optical Society
of America.
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8. Authors' Addresses
Fatai Zhang
Huawei Technologies
F3-5-B R&D Center, Huawei Base
Bantian, Longgang District
Shenzhen 518129 P.R.China
Phone: +86-755-28972912
Email: zhangfatai@huawei.com
Young Lee
Huawei
1700 Alma Drive, Suite 100
Plano, TX 75075
US
Phone: +1 972 509 5599 x2240
Fax: +1 469 229 5397
EMail: ylee@huawei.com
Oscar Gonzalez de Dios
Telefonica Investigacion y Desarrollo
Emilio Vargas 6
Madrid, 28045
Spain
Phone: +34 913374013
Email: ogondio@tid.es
Ramon Casellas
CTTC
Av. Carl Friedrich Gauss, 7
Castelldefels, 08860, Spain
Phone: +34 936452900
Email: ramon.casellas@cttc.es
Daniele Ceccarelli
Ericsson
Via A. Negrone 1/A
Genova - Sestri Ponente
Italy
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Email: daniele.ceccarelli@ericsson.com
Xiaobing Zi
Huawei Technologies
F3-5-B R&D Center, Huawei Base
Bantian, Longgang District
Shenzhen 518129 P.R.China
Phone: +86-755-28973229
Email: zixiaobing@huawei.com
Jianrui Han
Huawei Technologies
F3-5-B R&D Center, Huawei Base
Bantian, Longgang District
Shenzhen 518129 P.R.China
Phone: +86-755-28973229
Email: hanjianrui@huawei.com
Felipe Jimenez Arribas
Telefonica Investigacion y Desarrollo
Emilio Vargas 6
Madrid, 28045
Spain
Email: felipej@tid.es
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