draft-ietf-ccamp-flexi-grid-fwk-00.txt   draft-ietf-ccamp-flexi-grid-fwk-01.txt 
Network Working Group O. Gonzalez de Dios, Ed. Network Working Group O. Gonzalez de Dios, Ed.
Internet-Draft Telefonica I+D Internet-Draft Telefonica I+D
Intended status: Standards Track R. Casellas, Ed. Intended status: Standards Track R. Casellas, Ed.
Expires: April 05, 2014 CTTC Expires: August 18, 2014 CTTC
F. Zhang F. Zhang
Huawei Huawei
X. Fu X. Fu
ZTE ZTE
D. Ceccarelli D. Ceccarelli
Ericsson Ericsson
I. Hussain I. Hussain
Infinera Infinera
October 02, 2013 February 14, 2014
Framework and Requirements for GMPLS based control of Flexi-grid DWDM Framework and Requirements for GMPLS based control of Flexi-grid DWDM
networks networks
draft-ietf-ccamp-flexi-grid-fwk-00 draft-ietf-ccamp-flexi-grid-fwk-01
Abstract Abstract
This document defines a framework and the associated control plane This document defines a framework and the associated control plane
requirements for the GMPLS based control of flexi-grid DWDM networks. requirements for the GMPLS based control of flexi-grid DWDM networks.
To allow efficient allocation of optical spectral bandwidth for high To allow efficient allocation of optical spectral bandwidth for high
bit-rate systems, the International Telecommunication Union bit-rate systems, the International Telecommunication Union
Telecommunication Standardization Sector (ITU-T) has extended the Telecommunication Standardization Sector (ITU-T) has extended the
recommendations [G.694.1] and [G.872] to include the concept of recommendations [G.694.1] and [G.872] to include the concept of
flexible grid. A new DWDM grid has been developed within the ITU-T flexible grid. A new DWDM grid has been developed within the ITU-T
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Copyright Notice Copyright Notice
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4. Flexi-grid Networks . . . . . . . . . . . . . . . . . . . . . 4 4. Flexi-grid Networks . . . . . . . . . . . . . . . . . . . . . 4
4.1. Flexi-grid in the context of OTN . . . . . . . . . . . . 4 4.1. Flexi-grid in the context of OTN . . . . . . . . . . . . 4
4.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5 4.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
4.2.1. Frequency Slots . . . . . . . . . . . . . . . . . . . 5 4.2.1. Frequency Slots . . . . . . . . . . . . . . . . . . . 5
4.2.2. Media Channels . . . . . . . . . . . . . . . . . . . 7 4.2.2. Media Channels . . . . . . . . . . . . . . . . . . . 7
4.2.3. Media Layer Elements . . . . . . . . . . . . . . . . 7 4.2.3. Media Layer Elements . . . . . . . . . . . . . . . . 7
4.2.4. Optical Tributary Signals . . . . . . . . . . . . . . 8 4.2.4. Optical Tributary Signals . . . . . . . . . . . . . . 8
4.3. Flexi-grid layered network model . . . . . . . . . . . . 8 4.3. Flexi-grid layered network model . . . . . . . . . . . . 8
4.3.1. Hierarchy in the Media Layer . . . . . . . . . . . . 9 4.3.1. Hierarchy in the Media Layer . . . . . . . . . . . . 9
4.3.2. DWDM flexi-grid enabled network element models . . . 10 4.3.2. DWDM flexi-grid enabled network element models . . . 10
5. GMPLS applicability . . . . . . . . . . . . . . . . . . . . . 10 5. GMPLS applicability . . . . . . . . . . . . . . . . . . . . . 11
5.1. General considerations . . . . . . . . . . . . . . . . . 11 5.1. General considerations . . . . . . . . . . . . . . . . . 11
5.2. Considerations on TE Links . . . . . . . . . . . . . . . 11 5.2. Considerations on TE Links . . . . . . . . . . . . . . . 11
5.3. Considerations on Labeled Switched Path (LSP) in Flexi- 5.3. Considerations on Labeled Switched Path (LSP) in Flexi-
grid . . . . . . . . . . . . . . . . . . . . . . . . . . 13 grid . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.4. Control Plane modeling of Network elements . . . . . . . 17 5.4. Control Plane modeling of Network elements . . . . . . . 18
5.5. Media Layer Resource Allocation considerations . . . . . 17 5.5. Media Layer Resource Allocation considerations . . . . . 19
5.6. Neighbor Discovery and Link Property Correlation . . . . 21 5.6. Neighbor Discovery and Link Property Correlation . . . . 23
5.7. Path Computation / Routing and Spectrum Assignment (RSA) 21 5.7. Path Computation / Routing and Spectrum Assignment (RSA) 23
5.7.1. Architectural Approaches to RSA . . . . . . . . . . . 22 5.7.1. Architectural Approaches to RSA . . . . . . . . . . . 24
5.8. Routing / Topology dissemination . . . . . . . . . . . . 23 5.8. Routing / Topology dissemination . . . . . . . . . . . . 24
5.8.1. Available Frequency Ranges/slots of DWDM Links . . . 23 5.8.1. Available Frequency Ranges/slots of DWDM Links . . . 25
5.8.2. Available Slot Width Ranges of DWDM Links . . . . . . 23 5.8.2. Available Slot Width Ranges of DWDM Links . . . . . . 25
5.8.3. Spectrum Management . . . . . . . . . . . . . . . . . 23 5.8.3. Spectrum Management . . . . . . . . . . . . . . . . . 25
5.8.4. Information Model . . . . . . . . . . . . . . . . . . 24 5.8.4. Information Model . . . . . . . . . . . . . . . . . . 26
6. Control Plane Requirements . . . . . . . . . . . . . . . . . 25 6. Control Plane Requirements . . . . . . . . . . . . . . . . . 27
6.1. Functional requirements . . . . . . . . . . . . . . . . . 25 6.1. Support for Media Channels . . . . . . . . . . . . . . . 27
6.2. Routing/Topology Dissemination requirements . . . . . . . 25 6.2. Support for Media Channel Resizing . . . . . . . . . . . 27
6.3. Signaling requirements . . . . . . . . . . . . . . . . . 25 6.3. Support for Logical Associations of multiple media
7. Security Considerations . . . . . . . . . . . . . . . . . . . 25 channels . . . . . . . . . . . . . . . . . . . . . . . . 28
8. Contributing Authors . . . . . . . . . . . . . . . . . . . . 25 7. Security Considerations . . . . . . . . . . . . . . . . . . . 28
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 27 8. Contributing Authors . . . . . . . . . . . . . . . . . . . . 28
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 28 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 30
10.1. Normative References . . . . . . . . . . . . . . . . . . 28 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 30
10.2. Informative References . . . . . . . . . . . . . . . . . 29 10.1. Normative References . . . . . . . . . . . . . . . . . . 30
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29 10.2. Informative References . . . . . . . . . . . . . . . . . 32
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32
1. Requirements Language 1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2. Introduction 2. Introduction
The term "Flexible grid" (flexi-grid for short) as defined by the The term "Flexible grid" (flexi-grid for short) as defined by the
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4. Flexi-grid Networks 4. Flexi-grid Networks
4.1. Flexi-grid in the context of OTN 4.1. Flexi-grid in the context of OTN
[G.872] describes from a network level the functional architecture of [G.872] describes from a network level the functional architecture of
Optical Transport Networks (OTN). The OTN is decomposed into Optical Transport Networks (OTN). The OTN is decomposed into
independent layer networks with client/layer relationships among independent layer networks with client/layer relationships among
them. A simplified view of the OTN layers is shown in Figure 1. them. A simplified view of the OTN layers is shown in Figure 1.
+----------------+ +----------------+
| Digital Layer | | Digital Layer |
+----------------+ +----------------+
| Signal Layer | | Signal Layer |
+----------------+ +----------------+
| Media Layer | | Media Layer |
+----------------+ +----------------+
Figure 1: Generic OTN overview Figure 1: Generic OTN overview
In the OTN layering context, the media layer is the server layer of In the OTN layering context, the media layer is the server layer of
the optical signal layer. The optical signal is guided to its the optical signal layer. The optical signal is guided to its
destination by the media layer by means of a network media channel. destination by the media layer by means of a network media channel.
In the media layer, switching is based on a frequency slot, and the In the media layer, switching is based on a frequency slot, and the
size of a media channel is given by the properties of the associated size of a media channel is given by the properties of the associated
frequency slot. frequency slot.
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frequency slot is defined by its nominal central frequency and its frequency slot is defined by its nominal central frequency and its
slot width. slot width.
Nominal Central Frequency: each of the allowed frequencies as per the Nominal Central Frequency: each of the allowed frequencies as per the
definition of flexible DWDM grid in [G.694.1]. The set of nominal definition of flexible DWDM grid in [G.694.1]. The set of nominal
central frequencies can be built using the following expression f = central frequencies can be built using the following expression f =
193.1 THz + n x 0.00625 THz, where 193.1 THz is ITU-T ''anchor 193.1 THz + n x 0.00625 THz, where 193.1 THz is ITU-T ''anchor
frequency'' for transmission over the C band, n is a positive or frequency'' for transmission over the C band, n is a positive or
negative integer including 0. negative integer including 0.
-5 -4 -3 -2 -1 0 1 2 3 4 5 <- values of n -5 -4 -3 -2 -1 0 1 2 3 4 5 <- values of n
...+--+--+--+--+--+--+--+--+--+--+- ...+--+--+--+--+--+--+--+--+--+--+-
^ ^
193.1 THz <- anchor frequency 193.1 THz <- anchor frequency
Figure 2: Anchor frequency and set of nominal central frequencies Figure 2: Anchor frequency and set of nominal central frequencies
Nominal Central Frequency Granularity: It is the spacing between Nominal Central Frequency Granularity: It is the spacing between
allowed nominal central frequencies and it is set to 6.25 GHz (note: allowed nominal central frequencies and it is set to 6.25 GHz (note:
sometimes referred to as 0.00625 THz). sometimes referred to as 0.00625 THz).
Slot Width Granularity: 12.5 GHz, as defined in [G.694.1]. Slot Width Granularity: 12.5 GHz, as defined in [G.694.1].
Slot Width: The slot width determines the "amount" of optical Slot Width: The slot width determines the "amount" of optical
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| \ (1) | | (1) | | (1) / | | \ (1) | | (1) | | (1) / |
| \----|-----------------|-----------|-------------------|-----/ | | \----|-----------------|-----------|-------------------|-----/ |
+--------+ Link Channel +-----------+ Link Channel +--------+ +--------+ Link Channel +-----------+ Link Channel +--------+
Media Channel Media Channel Media Channel Media Channel Media Channel Media Channel
Matrix Matrix Matrix Matrix Matrix Matrix
(1) - Matrix Channel (1) - Matrix Channel
Figure 5: Simplified Layered Network Model Figure 5: Simplified Layered Network Model
A particular example of Optical Tributary Signal is the OCh-P. Figure A particular example of Optical Tributary Signal is the OCh-P.
Figure 6 shows the example of the layered network model Figure Figure 6 shows the example of the layered network model
particularized for the OCH-P case, as defined in G.805. particularized for the OCH-P case, as defined in G.805.
OCh AP Trail (OCh) OCh AP OCh AP Trail (OCh) OCh AP
O- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O O- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O
| | | |
--- OCh-P OCh-P --- --- OCh-P OCh-P ---
\ / source sink \ / \ / source sink \ /
+ + + +
| OCh-P OCh-P Network Connection OCh-P | | OCh-P OCh-P Network Connection OCh-P |
O TCP - - - - - - - - - - - - - - - - - - - - - - - - - - -TCP O O TCP - - - - - - - - - - - - - - - - - - - - - - - - - - -TCP O
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<Minimal Slot Width> <Minimal Slot Width>
<Maximal Slot Width> <Maximal Slot Width>
<Available Frequency Range-List> ::= <Available Frequency Range-List> ::=
<Available Frequency Range >[< Available Frequency Range-List>] <Available Frequency Range >[< Available Frequency Range-List>]
<Available Frequency Range >::= <Available Frequency Range >::=
<Start Spectrum Position><End Spectrum Position> | <Start Spectrum Position><End Spectrum Position> |
<Sets of contiguous slices> <Sets of contiguous slices>
<Available Central Frequency Granularity> ::= n x 6.25GHz, <Available Central Frequency Granularity> ::= n A&#151; 6.25GHz,
where n is positive integer, such as 6.25GHz, 12.5GHz, 25GHz, 50GHz where n is positive integer, such as 6.25GHz, 12.5GHz, 25GHz, 50GHz
or 100GHz or 100GHz
<Available Slot Width Granularity> ::= m x 12.5GHz, <Available Slot Width Granularity> ::= m A&#151; 12.5GHz,
where m is positive integer where m is positive integer
<Minimal Slot Width> ::= j x 12.5GHz, <Minimal Slot Width> ::= j x 12.5GHz,
j is a positive integer j is a positive integer
<Maximal Slot Width> ::= k x 12.5GHz, <Maximal Slot Width> ::= k x 12.5GHz,
k is a positive integer (k >= j) k is a positive integer (k >= j)
Figure 17: Routing Information model Figure 17: Routing Information model
6. Control Plane Requirements 6. Control Plane Requirements
This section provides a high level view of the requirements for GMPLS The GMPLS based control plane of a flexi-grid networks provides
/PCE flexi-grid control plane. A detailed list of requirements will aditional requirements to GMPLS. In this section the features to be
be provided in the next version of the document covered by GMPLS signaling for flexi-grid are identified. [Editor's
note: Only discussed requirements are included at this stage.
Routing requirements will come in the next version]
6.1. Functional requirements 6.1. Support for Media Channels
o It must be able to dynamically set up media channels The control plane SHALL be able to support Media Channels,
characterized by a single frequency slot. The representation of the
Media Channel in the GMPLS Control plane is the so-called flexi-grid
LSP. Since network media channels are media channels, an LSP may
also be the control plane representation of a network media channel.
Consequently, the control plane SHALL be able to support Network
Media Channels.
o It must be able to dynamically set up network media channels The signaling procedure SHALL be able to configure the nominal
central frequency (n) of a flexi-grid LSP.
o It must must be able to dynamically set up a set of co-routed The control plane protocols SHALL allow flexible range of values for
network media channels, and associate them logically the frequency slot width (m) parameter. Specifically, the control
plane SHALL allow setting up a media channel with frequency slot
width (m) ranging from a minimum of m=1 (12.5GHz) to a maximum of the
entire C-band with a slot width granularity of 12.5GHz.
6.2. Routing/Topology Dissemination requirements The signaling procedure of the GMPLS control plane SHALL be able to
configure the minimum width (m) of a flexi-grid LSP. In adition, the
control plane SHALL be able to configure local frecuency slots,
The computation entity needs to get the detailed network information: The control plane architecture SHOULD allow for the support of L-band
connectivity topology, node capabilities and available frequency and S-band
ranges of the links
6.3. Signaling requirements The signalling process of the control plane SHALL allow to collect
the local frequency slot asigned at each link along the path
o The signaling must be able to configure the minimum width (m) of 6.2. Support for Media Channel Resizing
an LSP.
o The signaling must be able to configure the nominal central The control plane SHALL allow resizing (grow or shrink) the frequency
frequency (n) of an LSP. slot width of a media channel/network media channel. The resizing
MAY imply resizing the local frequency slots along the path of the
flexi-grid LSP.
o It must be possible to collect the local frequency slot asigned at 6.3. Support for Logical Associations of multiple media channels
each link along the path
A set of media channels can be used to transport signals that have a
logical association between them. The control plane architecture
SHOULD allow multiple media channels to be logically associated. The
control plane SHOULD allow the co-routing of a set of media channels
logically associated
7. Security Considerations 7. Security Considerations
TBD TBD
8. Contributing Authors 8. Contributing Authors
Qilei Wang Qilei Wang
ZTE ZTE
Ruanjian Avenue, Nanjing, China Ruanjian Avenue, Nanjing, China
skipping to change at page 27, line 33 skipping to change at page 30, line 17
Marco Sosa Marco Sosa
Infinera Infinera
Biao Lu Biao Lu
Infinera Infinera
Abinder Dhillon Abinder Dhillon
Infinera Infinera
Felipe Jimenez Arribas Felipe Jimenez Arribas
Telefonica I+D TelefA^3nica I+D
Andrew G. Malis Andrew G. Malis
Verizon Verizon
Adrian Farrel Adrian Farrel
Old Dog Consulting Old Dog Consulting
Daniel King Daniel King
Old Dog Consulting Old Dog Consulting
Huub van Helvoort Huub van Helvoort
9. Acknowledgments 9. Acknowledgments
The authors would like to thank Pete Anslow for his insights and The authors would like to thank Pete Anslow for his insights and
clarifications. clarifications. This work was supported in part by the FP-7 IDEALIST
project under grant agreement number 317999.
10. References 10. References
10.1. Normative References 10.1. Normative References
[G.694.1] International Telecomunications Union, "ITU-T [G.694.1] International Telecomunications Union, "ITU-T
Recommendation G.694.1, Spectral grids for WDM Recommendation G.694.1, Spectral grids for WDM
applications: DWDM frequency grid", November 2012. applications: DWDM frequency grid", November 2012.
[G.709] International Telecomunications Union, "ITU-T [G.709] International Telecomunications Union, "ITU-T
Recommendation G.709, Interfaces for the Optical Transport Recommendation G.709, Interfaces for the Optical Transport
Network (OTN). ", March 2009. Network (OTN).", March 2009.
[G.800] International Telecomunications Union, "ITU-T [G.800] International Telecomunications Union, "ITU-T
Recommendation G.800, Unified functional architecture of Recommendation G.800, Unified functional architecture of
transport networks.", February 2012. transport networks.", February 2012.
[G.805] International Telecomunications Union, "ITU-T [G.805] International Telecomunications Union, "ITU-T
Recommendation G.805, Generic functional architecture of Recommendation G.805, Generic functional architecture of
transport networks.", March 2000. transport networks.", March 2000.
[G.8080] International Telecomunications Union, "ITU-T [G.8080] International Telecomunications Union, "ITU-T
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