draft-ietf-ccamp-flexi-grid-fwk-02.txt   draft-ietf-ccamp-flexi-grid-fwk-03.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: February 27, 2015 CTTC Expires: August 27, 2015 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
August 26, 2014 February 23, 2015
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-02 draft-ietf-ccamp-flexi-grid-fwk-03
Abstract Abstract
This document defines a framework and the associated control plane
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 its
recommendations [G.694.1] and [G.872] to include the concept of Recommendations G.694.1 and G.872 to include a new dense wavelength
flexible grid. A new DWDM grid has been developed within the ITU-T division multiplexing (DWDM) grid by defining a set of nominal
Study Group 15 by defining a set of nominal central frequencies, central frequencies, channel spacings and the concept of "frequency
channel spacings and the concept of "frequency slot". In such slot". In such an environment, a data plane connection is switched
environment, a data plane connection is switched based on allocated, based on allocated, variable-sized frequency ranges within the
variable-sized frequency ranges within the optical spectrum. optical spectrum creating what is known as a flexible grid (flexi-
grid).
This document defines a framework and the associated control plane
requirements for the GMPLS-based control of flexi-grid DWDM networks.
Status of This Memo Status of This Memo
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Table of Contents Table of Contents
1. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
4. Flexi-grid Networks . . . . . . . . . . . . . . . . . . . . . 4 2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 4
4.1. Flexi-grid in the context of OTN . . . . . . . . . . . . 4 3. Overview of Flexi-grid Networks . . . . . . . . . . . . . . . 5
4.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5 3.1. Flexi-grid in the Context of OTN . . . . . . . . . . . . 5
4.2.1. Frequency Slots . . . . . . . . . . . . . . . . . . . 5 3.2. Flexi-grid Terminology . . . . . . . . . . . . . . . . . 6
4.2.2. Media Channels . . . . . . . . . . . . . . . . . . . 7 3.2.1. Frequency Slots . . . . . . . . . . . . . . . . . . . 6
4.2.3. Media Layer Elements . . . . . . . . . . . . . . . . 7 3.2.2. Media Channels . . . . . . . . . . . . . . . . . . . 8
4.2.4. Optical Tributary Signals . . . . . . . . . . . . . . 8 3.2.3. Media Layer Elements . . . . . . . . . . . . . . . . 8
4.3. Flexi-grid layered network model . . . . . . . . . . . . 8 3.2.4. Optical Tributary Signals . . . . . . . . . . . . . . 9
4.3.1. Hierarchy in the Media Layer . . . . . . . . . . . . 9 3.2.5. Composite Media Channels . . . . . . . . . . . . . . 9
4.3.2. DWDM flexi-grid enabled network element models . . . 10 3.3. Hierarchy in the Media Layer . . . . . . . . . . . . . . 10
5. GMPLS applicability . . . . . . . . . . . . . . . . . . . . . 11 3.4. Flexi-grid Layered Network Model . . . . . . . . . . . . 10
5.1. General considerations . . . . . . . . . . . . . . . . . 11 3.4.1. DWDM Flexi-grid Enabled Network Element Models . . . 12
5.2. Considerations on TE Links . . . . . . . . . . . . . . . 11 4. GMPLS Applicability . . . . . . . . . . . . . . . . . . . . . 12
5.3. Considerations on Labeled Switched Path (LSP) in Flexi- 4.1. General Considerations . . . . . . . . . . . . . . . . . 12
grid . . . . . . . . . . . . . . . . . . . . . . . . . . 14 4.2. Consideration of TE Links . . . . . . . . . . . . . . . . 13
5.4. Control Plane modeling of Network elements . . . . . . . 18 4.3. Consideration of LSPs in Flexi-grid . . . . . . . . . . . 16
5.5. Media Layer Resource Allocation considerations . . . . . 19 4.4. Control Plane Modeling of Network Elements . . . . . . . 21
5.6. Neighbor Discovery and Link Property Correlation . . . . 23 4.5. Media Layer Resource Allocation Considerations . . . . . 21
5.7. Path Computation / Routing and Spectrum Assignment (RSA) 23 4.6. Neighbor Discovery and Link Property Correlation . . . . 25
5.7.1. Architectural Approaches to RSA . . . . . . . . . . . 24 4.7. Path Computation / Routing and Spectrum Assignment (RSA) 26
5.8. Routing / Topology dissemination . . . . . . . . . . . . 24 4.7.1. Architectural Approaches to RSA . . . . . . . . . . . 26
5.8.1. Available Frequency Ranges/slots of DWDM Links . . . 25 4.8. Routing and Topology Dissemination . . . . . . . . . . . 27
5.8.2. Available Slot Width Ranges of DWDM Links . . . . . . 25 4.8.1. Available Frequency Ranges/Slots of DWDM Links . . . 28
5.8.3. Spectrum Management . . . . . . . . . . . . . . . . . 25 4.8.2. Available Slot Width Ranges of DWDM Links . . . . . . 28
5.8.4. Information Model . . . . . . . . . . . . . . . . . . 26 4.8.3. Spectrum Management . . . . . . . . . . . . . . . . . 28
6. Control Plane Requirements . . . . . . . . . . . . . . . . . 27 4.8.4. Information Model . . . . . . . . . . . . . . . . . . 28
6.1. Support for Media Channels . . . . . . . . . . . . . . . 27 5. Control Plane Requirements . . . . . . . . . . . . . . . . . 30
6.2. Support for Media Channel Resizing . . . . . . . . . . . 27 5.1. Support for Media Channels . . . . . . . . . . . . . . . 30
6.3. Support for Logical Associations of multiple media 5.1.1. Signaling . . . . . . . . . . . . . . . . . . . . . . 31
channels . . . . . . . . . . . . . . . . . . . . . . . . 28 5.1.2. Routing . . . . . . . . . . . . . . . . . . . . . . . 31
7. Security Considerations . . . . . . . . . . . . . . . . . . . 28 5.2. Support for Media Channel Resizing . . . . . . . . . . . 32
8. Contributing Authors . . . . . . . . . . . . . . . . . . . . 28 5.3. Support for Logical Associations of Multiple Media
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 30 Channels . . . . . . . . . . . . . . . . . . . . . . . . 32
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 30 5.4. Support for Composite Media Channels . . . . . . . . . . 32
10.1. Normative References . . . . . . . . . . . . . . . . . . 30 5.5. Support for Neighbor Discovery and Link Property
10.2. Informative References . . . . . . . . . . . . . . . . . 32 Correlation . . . . . . . . . . . . . . . . . . . . . . . 32
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33
7. Security Considerations . . . . . . . . . . . . . . . . . . . 33
1. Requirements Language 8. Manageability Considerations . . . . . . . . . . . . . . . . 33
9. Contributing Authors . . . . . . . . . . . . . . . . . . . . 34
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 37
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 37
document are to be interpreted as described in [RFC2119]. 11.1. Normative References . . . . . . . . . . . . . . . . . . 37
11.2. Informative References . . . . . . . . . . . . . . . . . 38
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 39
2. Introduction 1. 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
International Telecommunication Union Telecommunication International Telecommunication Union Telecommunication
Standardization Sector (ITU-T) Study Group 15 in the latest version Standardization Sector (ITU-T) Study Group 15 in the latest version
of [G.694.1], refers to the updated set of nominal central of [G.694.1], refers to the updated set of nominal central
frequencies (a frequency grid), channel spacing and optical spectrum frequencies (a frequency grid), channel spacing and optical spectrum
management/allocation considerations that have been defined in order management/allocation considerations that have been defined in order
to allow an efficient and flexible allocation and configuration of to allow an efficient and flexible allocation and configuration of
optical spectral bandwidth for high bit-rate systems. optical spectral bandwidth for high bit-rate systems.
A key concept of flexi-grid is the "frequency slot"; a variable-sized A key concept of flexi-grid is the "frequency slot"; a variable-sized
optical frequency range that can be allocated to a data connection. optical frequency range that can be allocated to a data connection.
As detailed later in the document, a frequency slot is characterized As detailed later in the document, a frequency slot is characterized
by its nominal central frequency and its slot width which, as per by its nominal central frequency and its slot width which, as per
[G.694.1], is constrained to be a multiple of a given slot width [G.694.1], is constrained to be a multiple of a given slot width
granularity. granularity.
Compared to a traditional fixed grid network, which uses fixed size Compared to a traditional fixed grid network, which uses fixed size
optical spectrum frequency ranges or "frequency slots" with typical optical spectrum frequency ranges or frequency slots with typical
channel separations of 50 GHz, a flexible grid network can select its channel separations of 50 GHz, a flexible grid network can select its
media channels with a more flexible choice of slot widths, allocating media channels with a more flexible choice of slot widths, allocating
as much optical spectrum as required, allowing high bit rate signals as much optical spectrum as required.
(e.g., 400G, 1T or higher) that do not fit in the fixed grid.
From a networking perspective, a flexible grid network is assumed to From a networking perspective, a flexible grid network is assumed to
be a layered network [G.872][G.800] in which the media layer is the be a layered network [G.872][G.800] in which the media layer is the
server layer and the optical signal layer is the client layer. In server layer and the optical signal layer is the client layer. In
the media layer, switching is based on a frequency slot, and the size 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 of a media channel is given by the properties of the associated
frequency slot. In this layered network, the media channel frequency slot. In this layered network, the media channel can
transports an Optical Tributary Signal. transport more than one Optical Tributary Signals.
A Wavelength Switched Optical Network (WSON), addressed in [RFC6163], A Wavelength Switched Optical Network (WSON), addressed in [RFC6163],
is a term commonly used to refer to the application/deployment of a is a term commonly used to refer to the application/deployment of a
Generalized Multi-Protocol Label Switching (GMPLS)-based control GMPLS-based control plane for the control (provisioning/recovery,
plane for the control (provisioning/recovery, etc) of a fixed grid etc.) of a fixed grid wavelength division multiplexing (WDM) network
WDM network in which media (spectrum) and signal are jointly in which media (spectrum) and signal are jointly considered.
considered
This document defines the framework for a GMPLS-based control of This document defines the framework for a GMPLS-based control of
flexi-grid enabled DWDM networks (in the scope defined by ITU-T flexi-grid enabled dense wavelength division multiplexing (DWDM)
layered Optical Transport Networks [G.872]), as well as a set of networks (in the scope defined by ITU-T layered Optical Transport
associated control plane requirements. An important design Networks [G.872]), as well as a set of associated control plane
consideration relates to the decoupling of the management of the requirements. An important design consideration relates to the
optical spectrum resource and the client signals to be transported. decoupling of the management of the optical spectrum resource and the
client signals to be transported.
3. Acronyms 2. Terminology
Further terminology specific to flexi-grid networks can be found in
Section 3.2.
2.1. Requirements Language
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 [RFC2119].
2.2. Abbreviations
EFS: Effective Frequency Slot EFS: Effective Frequency Slot
FS: Frequency Slot FS: Frequency Slot
FSC: Fiber-Switch Capable
LSR: Label Switching Router
NCF: Nominal Central Frequency NCF: Nominal Central Frequency
OCh: Optical Channel OCh: Optical Channel
OCh-P: Optical Channel Payload OCh-P: Optical Channel Payload
OTSi: Optical Tributary Signal
OTS: Optical Tributary Signal OTSiG: OTSi Group is the set of OTSi signals
OCC: Optical Channel Carrier OCC: Optical Channel Carrier
PCE: Path Computation Element
ROADM: Reconfigurable Optical Add-Drop Multiplexer
SSON: Spectrum-Switched Optical Network
SWG: Slot Width Granularity SWG: Slot Width Granularity
4. Flexi-grid Networks 3. Overview of Flexi-grid Networks
4.1. Flexi-grid in the context of OTN 3.1. 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
Optical Transport Networks (OTN). The OTN is decomposed into of 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.
size of a media channel is given by the properties of the associated
frequency slot.
In this scope, this document uses the term flexi-grid enabled DWDM In this scope, this document uses the term flexi-grid enabled DWDM
network to refer to a network in which switching is based on network to refer to a network in which switching is based on
frequency slots defined using the flexible grid, and covers mainly frequency slots defined using the flexible grid, and covers mainly
the Media Layer as well as the required adaptations from the Signal the Media Layer as well as the required adaptations from the Signal
layer. The present document is thus focused on the control and layer. The present document is thus focused on the control and
management of the media layer. management of the media layer.
4.2. Terminology 3.2. Flexi-grid Terminology
This section presents the definition of the terms used in flexi-grid This section presents the definition of the terms used in flexi-grid
networks. These terms are included in the ITU-T recommendations networks. More detail about these terms can be found in the ITU-T
[G.694.1], [G.872]), [G.870], [G.8080] and [G.959.1-2013]. Recommendations [G.694.1], [G.872]), [G.870], [G.8080], and
[G.959.1-2013].
Where appropriate, this documents also uses terminology and Where appropriate, this documents also uses terminology and
lexicography from [RFC4397]. lexicography from [RFC4397].
4.2.1. Frequency Slots 3.2.1. Frequency Slots
This subsection is focused on the frequency slot related terms. This subsection is focused on the frequency slot related terms.
o Frequency Slot [G.694.1]: The frequency range allocated to a slot o Frequency Slot [G.694.1]: The frequency range allocated to a slot
within the flexible grid and unavailable to other slots. A within the flexible grid and unavailable to other slots. A
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 o Effective Frequency Slot [G.870]: The effective frequency slot of
definition of flexible DWDM grid in [G.694.1]. The set of nominal a media channel is that part of the frequency slots of the filters
central frequencies can be built using the following expression f = along the media channel that is common to all of the filters'
193.1 THz + n x 0.00625 THz, where 193.1 THz is ITU-T ''anchor frequency slots. Note that both the Frequency Slot and Effective
frequency'' for transmission over the C band, n is a positive or Frequency Slot are both local terms.
negative integer including 0.
-5 -4 -3 -2 -1 0 1 2 3 4 5 <- values of n o Nominal Central Frequency: Each of the allowed frequencies as per
...+--+--+--+--+--+--+--+--+--+--+- the definition of flexible DWDM grid in [G.694.1]. The set of
^ nominal central frequencies can be built using the following
193.1 THz <- anchor frequency expression
Figure 2: Anchor frequency and set of nominal central frequencies f = 193.1 THz + n x 0.00625 THz
Nominal Central Frequency Granularity: It is the spacing between where 193.1 THz is ITU-T "anchor frequency" for transmission over
allowed nominal central frequencies and it is set to 6.25 GHz (note: the C band, and n is a positive or negative integer including 0.
sometimes referred to as 0.00625 THz).
Slot Width Granularity: 12.5 GHz, as defined in [G.694.1]. -5 -4 -3 -2 -1 0 1 2 3 4 5 <- values of n
...+--+--+--+--+--+--+--+--+--+--+-
^
193.1 THz <- anchor frequency
Slot Width: The slot width determines the "amount" of optical Figure 2: Anchor Frequency and Set of Nominal Central Frequencies
spectrum regardless of its actual "position" in the frequency axis.
A slot width is constrained to be m x SWG (that is, m x 12.5 GHz),
where m is an integer greater than or equal to 1.
Frequency Slot 1 Frequency Slot 2 o Nominal Central Frequency Granularity: This is the spacing between
------------- ------------------- allowed nominal central frequencies and it is set to 6.25 GHz.
| | | |
-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 3: Example Frequency slots o Slot Width Granularity (SWG): 12.5 GHz, as defined in [G.694.1].
o The symbol '+' represents the allowed nominal central frequencies, o Slot Width: The slot width determines the "amount" of optical
the '--' represents the nominal central frequency granularity, and spectrum regardless of its actual "position" in the frequency
the '^' represents the slot nominal central frequency. The number axis. A slot width is constrained to be m x SWG (that is, m x
on the top of the '+' symbol represents the 'n' in the frequency 12.5 GHz), where m is an integer greater than or equal to 1.
calculation formula. The nominal central frequency is 193.1 THz
when n equals zero.
Effective Frequency Slot: the effective frequency slot of a media Frequency Slot 1 Frequency Slot 2
channel is the common part of the frequency slots along the media ------------- -------------------
channel through a particular path through the optical network. It is | | | |
a logical construct derived from the (intersection of) frequency -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11
slots allocated to each device in the path. The effective frequency ...--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--...
slot is an attribute of a media channel and, being a frequency slot, ------------- -------------------
it is described by its nominal central frequency and slot width, ^ ^
according to the already described rules. Central F = 193.1THz Central F = 193.14375 THz
Slot width = 25 GHz Slot width = 37.5 GHz
Figure 3: Example Frequency Slots
* The symbol '+' represents the allowed nominal central
frequencies
* The '--' represents the nominal central frequency granularity
* The '^' represents the slot nominal central frequency
* The number on the top of the '+' symbol represents the 'n' in
the frequency calculation formula.
* The nominal central frequency is 193.1 THz when n equals zero.
o Effective Frequency Slot: The effective frequency slot of a media
channel is the common part of the frequency slots along the media
channel through a particular path through the optical network. It
is a logical construct derived from the (intersection of)
frequency slots allocated to each device in the path. The
effective frequency slot is an attribute of a media channel and,
being a frequency slot, it is described by its nominal central
frequency and slot width, according to the already described
rules.
Frequency Slot 1 Frequency Slot 1
------------- -------------
| | | |
-3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11
..--+--+--+--+--X--+--+--+--+--+--+--+--+--+--+--+--... ..--+--+--+--+--X--+--+--+--+--+--+--+--+--+--+--+--...
Frequency Slot 2 Frequency Slot 2
------------------- -------------------
| | | |
skipping to change at page 7, line 26 skipping to change at page 8, line 26
=============================================== ===============================================
Effective Frequency Slot Effective Frequency Slot
------------- -------------
| | | |
-3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11
..--+--+--+--+--X--+--+--+--+--+--+--+--+--+--+--+--... ..--+--+--+--+--X--+--+--+--+--+--+--+--+--+--+--+--...
Figure 4: Effective Frequency Slot Figure 4: Effective Frequency Slot
4.2.2. Media Channels 3.2.2. Media Channels
Media Channel: a media association that represents both the topology This section defines concepts such as (Network) Media Channel; the
(i.e., path through the media) and the resource (frequency slot) that mapping to GMPLS constructs (i.e., LSP) is detailed in Section 4.
it occupies. As a topological construct, it represents a (effective)
frequency slot supported by a concatenation of media elements
(fibers, amplifiers, filters, switching matrices...). This term is
used to identify the end-to-end physical layer entity with its
corresponding (one or more) frequency slots local at each link
filters.
Network Media Channel: It is a media channel that transports an o Media Channel: A media association that represents both the
Optical Tributary Signal [Editor's note: this definition goes beyond topology (i.e., path through the media) and the resource
current G.870 definition, which is still tightened to a particular (frequency slot) that it occupies. As a topological construct, it
case of OTS, the OCh-P] represents a frequency slot (an effective frequency slot)
supported by a concatenation of media elements (fibers,
amplifiers, filters, switching matrices...). This term is used to
identify the end-to-end physical layer entity with its
corresponding (one or more) frequency slots local at each link
filters.
4.2.3. Media Layer Elements o Network Media Channel: [G.870] defines the Network Media Channel
in terms of the media channel that transports the OTSi. This
document broadens the definition to cover any OTSi so that a
Network Media Channel is a media channel that transports an OTSi.
Media Element: a media element only directs the optical signal or 3.2.3. Media Layer Elements
affects the properties of an optical signal, it does not modify the
properties of the information that has been modulated to produce the
optical signal [G.870]. Examples of media elements include fibers,
amplifiers, filters and switching matrices.
Media Channel Matrixes: the media channel matrix provides flexible o Media Element: A media element directs an optical signal or
connectivity for the media channels. That is, it represents a point affects the properties of an optical signal. It does not modify
of flexibility where relationships between the media ports at the the properties of the information that has been modulated to
edge of a media channel matrix may be created and broken. The produce the optical signal [G.870]. Examples of media elements
relationship between these ports is called a matrix channel. include fibers, amplifiers, filters, and switching matrices.
(Network) Media Channels are switched in a Media Channel Matrix.
4.2.4. Optical Tributary Signals o Media Channel Matrixes: The media channel matrix provides flexible
connectivity for the media channels. That is, it represents a
point of flexibility where relationships between the media ports
at the edge of a media channel matrix may be created and broken.
The relationship between these ports is called a matrix channel.
(Network) Media Channels are switched in a Media Channel Matrix.
Optical Tributary Signal [G.959.1-2013]: The optical signal that is 3.2.4. Optical Tributary Signals
placed within a network media channel for transport across the
optical network. This may consist of a single modulated optical
carrier or a group of modulated optical carriers or subcarriers. One
particular example of Optical Tributary Signal is an Optical Channel
Payload (OCh-P) [G.872].
4.3. Flexi-grid layered network model o Optical Tributary Signal (OTSi) [G.959.1-2013]: The optical signal
that is placed within a network media channel for transport across
the optical network. This may consist of a single modulated
optical carrier or a group of modulated optical carriers or
subcarriers. To provide a connection between the OTSi source and
the OTSi sink the optical signal must be assigned to a network
media channel.
In the OTN layered network, the network media channel transports a o OTSi Group (OTSiG): The set of OTSi signals that are carried by a
single Optical Tributary Signal (see Figure 5) group of network media channels. Each OTSi is carried by one
network media channel. From a management perspective it should be
possible to manage both the OTSiG and a group of Network Media
Channels as single entities.
3.2.5. Composite Media Channels
o It is possible to construct an end-to-end media channel as a
composite of more than one network media channels. A composite
media channel carries a group of OTSi (i.e., OTSiG). Each OTSi is
carried by one network media channel. This group of OTSi should
be carried over a single fibre.
o In this case, the effective frequency slots may be contiguous
(i.e., there is no spectrum between them that can be used for
other media channels) or non-contiguous.
o It is not currently envisaged that such composite media channels
may be constructed from slots carried on different fibers whether
those fibers traverse the same hop-by-hop path through the network
or not.
o Furthermore, it is not considered likely that a media channel may
be constructed from a different variation of slot composition on
each hop. That is, the slot composition must be the same from one
end to the other of the media channel even if the specific slots
and their spacing may vary hop by hop.
o How the signal is carried across such groups of network media
channels is out of scope for this document.
3.3. Hierarchy in the Media Layer
In summary, the concept of frequency slot is a logical abstraction
that represents a frequency range, while the media layer represents
the underlying media support. Media Channels are media associations,
characterized by their (effective) frequency slot, respectively; and
media channels are switched in media channel matrixes. From the
control and management perspective, a media channel can be logically
split into network media channels.
In Figure 5, a media channel has been configured and dimensioned to
support two network media channels, each of them carrying one optical
tributary signal.
Media Channel Frequency Slot
+-------------------------------X------------------------------+
| |
| Frequency Slot Frequency Slot |
| +------------X-----------+ +----------X-----------+ |
| | Opt Tributary Signal | | Opt Tributary Signal | |
| | o | | o | |
| | | | | | | |
-4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12
--+---+---+---+---+---+---+---+---+---+---+---+--+---+---+---+---+--
<- Network Media Channel-> <- Network Media Channel->
<------------------------ Media Channel ----------------------->
X - Frequency Slot Central Frequency
o - signal central frequency
Figure 5: Example of Media Channel / Network Media Channels and
Associated Frequency Slots
3.4. Flexi-grid Layered Network Model
In the OTN layered network, the network media channel transports a
single Optical Tributary Signal (see Figure 6)
| Optical Tributary Signal | | Optical Tributary Signal |
O - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O O - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O
| | | |
| Channel Port Network Media Channel Channel Port | | Channel Port Network Media Channel Channel Port |
O - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O O - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O
| | | |
+--------+ +-----------+ +--------+ +--------+ +-----------+ +--------+
| \ (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 The symbol (1) indicates a Matrix Channel
Figure 5: Simplified Layered Network Model Figure 6: Simplified Layered Network Model
A particular example of Optical Tributary Signal is the OCh-P. A particular example of Optical Tributary Signal is the OCh-P.
Figure Figure 6 shows the example of the layered network model Figure 7 shows this specific example as defined in G.805 [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
| | | |
|Channel Port Network Media Channel Channel Port | |Channel Port Network Media Channel Channel Port |
O - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O O - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - O
| | | |
+--------+ +-----------+ +---------+ +--------+ +-----------+ +---------+
| \ (1) | OCh-P LC | (1) | OCh-P LC | (1) / | | \ (1) | OCh-P LC | (1) | OCh-P LC | (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 The symbol (1) indicates a Matrix Channel
Figure 6: Layered Network Model according to G.805
By definition a network media channel only supports a single Optical
Tributary signal. How several Optical Tributary signals are bound
together is out of the scope of the present document and is a matter
of the signal layer.
4.3.1. Hierarchy in the Media Layer
In summary, the concept of frequency slot is a logical abstraction
that represents a frequency range while the media layer represents
the underlying media support. Media Channels are media associations,
characterized by their (effective) frequency slot, respectively; and
media channels are switched in media channel matrixes. From the
control and management perspective, a media channel can be logically
splited in other media channels.
In Figure 7 , a Media Channel has been configured and dimensioned to
support two network media channels, each of them carrying one optical
tributary signal.
Media Channel Frequency Slot
+-------------------------------X------------------------------+
| |
| Frequency Slot Frequency Slot |
| +------------X-----------+ +----------X-----------+ |
| | Opt Tributary Signal | | Opt Tributary Signal | |
| | o | | o | |
| | | | | | | |
-4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12
+---+---+---+---+---+---+---+---+---+---+---+--+---+---+---+---+---
<- Network Media Channel-> <- Network Media Channel->
<------------------------ Media Channel ----------------------->
X - Frequency Slot Central Frequency
o - signal central frequency Figure 7: Layered Network Model According to G.805
Figure 7: Example of Media Channel / Network Media Channels and By definition, a network media channel supports only a single Optical
associated frequency slots Tributary Signal.
4.3.2. DWDM flexi-grid enabled network element models 3.4.1. DWDM Flexi-grid Enabled Network Element Models
Similar to fixed grid networks, a flexible grid network is also A flexible grid network is constructed from subsystems that include
constructed from subsystems that include Wavelength Division WDM links, tunable transmitters, and receivers, (i.e, media elements
Multiplexing (WDM) links, tunable transmitters and receivers, i.e, including media layer switching elements that are media matrices) as
media elements including media layer switching elements (media well as electro-optical network elements. This is just the same as
matrices), as well as electro-optical network elements, all of them in a fixed grid network except that each element has flexible grid
with flexible grid characteristics. characteristics.
As stated in [G.694.1] the flexible DWDM grid defined in Clause 7 has As stated in Clause 7 of [G.694.1] the flexible DWDM grid has a
a nominal central frequency granularity of 6.25 GHz and a slot width nominal central frequency granularity of 6.25 GHz and a slot width
granularity of 12.5 GHz. However, devices or applications that make granularity of 12.5 GHz. However, devices or applications that make
use of the flexible grid may not be capable of supporting every use of the flexible grid might not be capable of supporting every
possible slot width or position. In other words, applications may be possible slot width or position. In other words, applications may be
defined where only a subset of the possible slot widths and positions defined where only a subset of the possible slot widths and positions
are required to be supported. For example, an application could be are required to be supported. For example, an application could be
defined where the nominal central frequency granularity is 12.5 GHz defined where the nominal central frequency granularity is 12.5 GHz
(by only requiring values of n that are even) and that only requires (by only requiring values of n that are even) and that only requires
slot widths as a multiple of 25 GHz (by only requiring values of m slot widths as a multiple of 25 GHz (by only requiring values of m
that are even). that are even).
5. GMPLS applicability 4. GMPLS Applicability
The goal of this section is to provide an insight of the application The goal of this section is to provide an insight into the
of GMPLS to control flexi-grid networks, while specific requirements application of GMPLS as a control mechanism in flexi-grid networks.
are covered in the next section. The present framework is aimed at Specific control plane requirements for the support of flexi-grid
controlling the media layer within the Optical Transport Network networks are covered in Section 5. This framework is aimed at
(OTN) hierarchy and the required adaptations of the signal layer. controlling the media layer within the OTN hierarchy, and controlling
This document also defines the term SSON (Spectrum-Switched Optical the required adaptations of the signal layer. This document also
Network) to refer to a Flexi-grid enabled DWDM network that is defines the term Spectrum-Switched Optical Network (SSON) to refer to
controlled by a GMPLS/PCE control plane. a Flexi-grid enabled DWDM network that is controlled by a GMPLS/PCE
control plane.
This section provides a mapping of the ITU-T G.872 architectural This section provides a mapping of the ITU-T G.872 architectural
aspects to GMPLS/Control plane terms, and considers the relationship aspects to GMPLS/Control plane terms, and considers the relationship
between the architectural concept/construct of media channel and its between the architectural concept/construct of media channel and its
control plane representations (e.g. as a TE link). control plane representations (e.g., as a TE link).
5.1. General considerations 4.1. General Considerations
The GMPLS control of the media layer deals with the establishment of The GMPLS control of the media layer deals with the establishment of
media channels, which are switched in media channel matrixes. GMPLS media channels that are switched in media channel matrices. GMPLS
labels locally represent the media channel and its associated labels are used to locally represent the media channel and its
frequency slot. Network media channels are considered a particular associated frequency slot. Network media channels are considered a
case of media channels when the end points are transceivers (that is, particular case of media channels when the end points are
source and destination of an Optical Tributary Signal) transceivers (that is, source and destination of an Optical Tributary
Signal)
5.2. Considerations on TE Links 4.2. Consideration of TE Links
From a theoretical / abstract point of view, a fiber can be modeled From a theoretical / abstract point of view, a fiber can be modeled
has having a frequency slot that ranges from (-inf, +inf). This as having a frequency slot that ranges from minus infinity to plus
representation helps understand the relationship between frequency infinity. This representation helps understand the relationship
slots / ranges. between frequency slots and ranges.
The frequency slot is a local concept that applies locally to a The frequency slot is a local concept that applies within a component
component / element. When applied to a media channel, we are or element. When applied to a media channel, we are referring to its
referring to its effective frequency slot as defined in [G.872]. effective frequency slot as defined in [G.872].
The association of a filter, a fiber and a filter is a media channel The association of the three components a filter, a fiber, and a
in its most basic form, which from the control plane perspective may filter, is a media channel in its most basic form. From the control
modeled as a (physical) TE-link with a contiguous optical spectrum at plane perspective this may modeled as a (physical) TE-link with a
start of day. A means to represent this is that the portion of contiguous optical spectrum. This can be represented by saying that
spectrum available at time t0 depends on which filters are placed at the portion of spectrum available at time t0 depends on which filters
the ends of the fiber and how they have been configured. Once are placed at the ends of the fiber and how they have been
filters are placed we have the one hop media channel. In practical configured. Once filters are placed we have a one-hop media channel.
terms, associating a fiber with the terminating filters determines In practical terms, associating a fiber with the terminating filters
the usable optical spectrum. determines the usable optical spectrum.
-----------------+ +-----------------+ ---------------+ +-----------------+
| | | |
+--------+ +--------+ +--------+ +--------+
| | | | +--------- | | | | +---------
---o| =============================== o--| ---o| =============================== o--|
| | Fiber | | | --\ /-- | | Fiber | | | --\ /--
---o| | | o--| \/ ---o| | | o--| \/
| | | | | /\ | | | | | /\
---o| =============================== o--| --/ \-- ---o| =============================== o--| --/ \--
| Filter | | Filter | | | Filter | | Filter | |
| | | | +--------- | | | | +---------
+--------+ +--------+ +--------+ +--------+
| | | |
|------- Basic Media Channel ---------| |------- Basic Media Channel ---------|
-----------------+ +-----------------+ ---------------+ +-----------------+
--------+ +-------- --------+ +--------
|--------------------------------------| |--------------------------------------|
LSR | TE link | LSR LSR | TE link | LSR
|--------------------------------------| |--------------------------------------|
+--------+ +-------- +--------+ +--------
Figure 8: (Basic) Media channel and TE link Figure 8: (Basic) Media Channel and TE Link
Additionally, when a cross-connect for a specific frequency slot is Additionally, when a cross-connect for a specific frequency slot is
considered, the underlying media support is still a media channel, considered, the underlying media support is still a media channel,
augmented, so to speak, with a bigger association of media elements augmented, so to speak, with a bigger association of media elements
and a resulting effective slot. When this media channel is the and a resulting effective slot. When this media channel is the
result of the association of basic media channels and media layer result of the association of basic media channels and media layer
matrix cross-connects, this architectural construct can be matrix cross-connects, this architectural construct can be
represented as / corresponds to a Label Switched Path (LSP) from a represented as (i.e., corresponds to) a Label Switched Path (LSP)
control plane perspective. In other words, It is possible to from a control plane perspective. In other words, It is possible to
"concatenate" several media channels (e.g. Patch on intermediate "concatenate" several media channels (e.g., Patch on intermediate
nodes) to create a single media channel. nodes) to create a single media channel.
-----------+ +------------------------------+ +---------- ----------+ +------------------------------+ +---------
| | | | | | | |
+------+ +------+ +------+ +------+ +------+ +------+ +------+ +------+
| | | | +----------+ | | | | | | | | +----------+ | | | |
--o| ========= o--| |--o ========= o-- --o| ========= o--| |--o ========= o--
| | Fiber | | | --\ /-- | | | Fiber | | | | Fiber | | | --\ /-- | | | Fiber | |
--o| | | o--| \/ |--o | | o-- --o| | | o--| \/ |--o | | o--
| | | | | /\ | | | | | | | | | | /\ | | | | |
--o| ========= o--***********|--o ========= o-- --o| ========= o--***********|--o ========= o--
|Filter| |Filter| | | |Filter| |Filter| |Filter| |Filter| | | |Filter| |Filter|
| | | | | | | | | | | | | | | |
+------+ +------+ +------+ +------+ +------+ +------+ +------+ +------+
| | | | | | | |
<- Basic Media -> <- Matrix -> <- Basic Media-> <- Basic Media -> <- Matrix -> <- Basic Media->
|Channel| Channel |Channel| |Channel| Channel |Channel|
-----------+ +------------------------------+ +---------- ----------+ +------------------------------+ +---------
<-------------------- Media Channel ----------------> <-------------------- Media Channel ---------------->
-----+ +---------------+ +------- ------+ +---------------+ +------
|------------------| |------------------| |------------------| |------------------|
LSR | TE link | LSR | TE link | LSR LSR | TE link | LSR | TE link | LSR
|------------------| |------------------| |------------------| |------------------|
-----+ +---------------+ +------- ------+ +---------------+ +------
Figure 9: Extended Media Channel Figure 9: Extended Media Channel
Additionally, if appropriate, it can also be represented as a TE link Furthermore, if appropriate, the media channel can also be
or Forwarding Adjacency (FA), augmenting the control plane network represented as a TE link or Forwarding Adjacency (FA) [RFC4206],
model. augmenting the control plane network model.
-----------+ +------------------------------+ +---------- ----------+ +------------------------------+ +---------
| | | | | | | |
+------+ +------+ +------+ +------+ +------+ +------+ +------+ +------+
| | | | +----------+ | | | | | | | | +----------+ | | | |
--o| ========= o--| |--o ========= o-- --o| ========= o--| |--o ========= o--
| | Fiber | | | --\ /-- | | | Fiber | | | | Fiber | | | --\ /-- | | | Fiber | |
--o| | | o--| \/ |--o | | o-- --o| | | o--| \/ |--o | | o--
| | | | | /\ | | | | | | | | | | /\ | | | | |
--o| ========= o--***********|--o ========= o-- --o| ========= o--***********|--o ========= o--
|Filter| |Filter| | | |Filter| |Filter| |Filter| |Filter| | | |Filter| |Filter|
| | | | | | | | | | | | | | | |
+------+ +------+ +------+ +------+ +------+ +------+ +------+ +------+
| | | | | | | |
-----------+ +------------------------------+ +---------- ----------+ +------------------------------+ +---------
<------------------------ Media Channel -----------> <------------------------ Media Channel ----------->
+-----+ +------ ------+ +-----
|------------------------------------------------------| |------------------------------------------------------|
LSR | TE link | LSR LSR | TE link | LSR
|------------------------------------------------------| |------------------------------------------------------|
+-----+ +------ ------+ +-----
Figure 10: Extended Media Channel / TE Link / FA Figure 10: Extended Media Channel / TE Link / FA
5.3. Considerations on Labeled Switched Path (LSP) in Flexi-grid 4.3. Consideration of LSPs in Flexi-grid
The flexi-grid LSP is seen as a control plane representation of a The flexi-grid LSP is a control plane representation of a media
media channel. Since network media channels are media channels, an channel. Since network media channels are media channels, an LSP may
LSP may also be the control plane representation of a network media also be the control plane representation of a network media channel
channel, in a particular context. From a control plane perspective, (without considering the adaptation functions). From a control plane
the main difference (regardless of the actual effective frequency perspective, the main difference (regardless of the actual effective
slot which may be dimensioned arbitrarily) is that the LSP that frequency slot which may be dimensioned arbitrarily) is that the LSP
represents a network media channel also includes the endpoints that represents a network media channel also includes the endpoints
(transceivers) , including the cross-connects at the ingress / egress (transceivers), including the cross-connects at the ingress and
nodes. The ports towards the client can still be represented as egress nodes. The ports towards the client can still be represented
interfaces from the control plane perspective. as interfaces from the control plane perspective.
Figure 11 describes an LSP routed along 3 nodes. The LSP is Figure 11 shows an LSP routed between 3 nodes. The LSP is terminated
terminated before the optical matrix of the ingress and egress nodes before the optical matrix of the ingress and egress nodes and can
and can represent a Media Channel. This case does NOT (and cannot) represent a media channel. This case does not (and cannot) represent
represent a network media channel as it does not include (and cannot a network media channel because it does not include (and cannot
include) the transceivers. include) the transceivers.
----------+ +--------------------------------+ +--------- ---------+ +--------------------------------+ +--------
| | | | | | | |
+------+ +------+ +------+ +------+ +------+ +------+ +------+ +------+
| | | | +----------+ | | | | | | | | +----------+ | | | |
-o| ========= o---| |---o ========= o- -o| ========= o---| |---o ========= o-
| | Fiber | | | --\ /-- | | | Fiber | | | | Fiber | | | --\ /-- | | | Fiber | |
-o|>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>o- -o|>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>o-
| | | | | /\ | | | | | | | | | | /\ | | | | |
-o| ========= o---***********|---o ========= o- -o| ========= o---***********|---o ========= o-
|Filter| |Filter| | | |Filter| |Filter| |Filter| |Filter| | | |Filter| |Filter|
| | | | | | | | | | | | | | | |
+------+ +------+ +------+ +------+ +------+ +------+ +------+ +------+
| | | | | | | |
----------+ +--------------------------------+ +--------- ---------+ +--------------------------------+ +--------
>>>>>>>>>>>>>>>>>>>>>>>>>>>> LSP >>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>>>>>>> LSP >>>>>>>>>>>>>>>>>>>>>>>>
-----+ +---------------+ +----- -----+ +---------------+ +-----
|------------------| |----------------| |------------------| |----------------|
LSR | TE link | LSR | TE link | LSR LSR | TE link | LSR | TE link | LSR
|------------------| |----------------| |------------------| |----------------|
-----+ +---------------+ +----- -----+ +---------------+ +-----
Figure 11: Flex-grid LSP representing a media channel that starts at Figure 11: Flex-grid LSP Representing a Media Channel that Starts at
the filter of the outgoing interface of the ingress LSR and ends at the Filter of the Outgoing Interface of the Ingress LSR and ends at
the filter of the incoming interface of the egress LSR the Filter of the Incoming Interface of the Egress LSR
In Figure 12 a Network Media Channel is represented as terminated at In Figure 12 a Network Media Channel is represented as terminated at
the DWDM side of the transponder, this is commonly named as OCh-trail the DWDM side of the transponder. This is commonly named as OCh-
connection. trail connection.
|--------------------- Network Media Channel ----------------------| |--------------------- Network Media Channel ----------------------|
+----------------------+ +----------------------+ +----------------------+ +----------------------+
| | | | | |
+------+ +------+ +------+ +------+ +------+ +------+ +------+ +------+
| | +----+ | | | | +----+ | |OCh-P | | +----+ | | | | +----+ | |OTSi
OCh-P| o-| |-o | +-----+ | o-| |-o |sink OTSi| o-| |-o | +-----+ | o-| |-o |sink
src | | | | | ===+-+ +-+==| | | | | O---|R src | | | | | ===+-+ +-+==| | | | | O---|R
T|***o******o******************************************************** T|***o******o********************************************************
| | |\ /| | | | | | | | |\ /| | | | | |\ /| | | | | | | | |\ /| | |
| o-| \/ |-o ===| | | |==| o-| \/ |-o | | o-| \/ |-o ===| | | |==| o-| \/ |-o |
| | | /\ | | | +-+ +-+ | | | /\ | | | | | | /\ | | | +-+ +-+ | | | /\ | | |
| o-|/ \|-o | | \/ | | o-|/ \|-o | | o-|/ \|-o | | \/ | | o-|/ \|-o |
|Filter| | | |Filter| | /\ | |Filter| | | |Filter| |Filter| | | |Filter| | /\ | |Filter| | | |Filter|
+------+ | | +------+ +-----+ +------+ | | +------+ +------+ | | +------+ +-----+ +------+ | | +------+
| | | | | | | | | | | | | | | |
+----------------------+ +----------------------+ +----------------------+ +----------------------+
skipping to change at page 16, line 33 skipping to change at page 18, line 33
<-------------------------------------------------------------------> <------------------------------------------------------------------->
LSP LSP
<------------------------------------------------------------------> <------------------------------------------------------------------>
+-----+ +--------+ +-----+ +-----+ +--------+ +-----+
o--- | |-------------------| |----------------| |---o o--- | |-------------------| |----------------| |---o
| LSR | TE link | LSR | TE link | LSR | | LSR | TE link | LSR | TE link | LSR |
| |-------------------| |----------------| | | |-------------------| |----------------| |
+-----+ +--------+ +-----+ +-----+ +--------+ +-----+
Figure 12: LSP representing a network media channel (OCh-Trail) Figure 12: LSP Representing a Network Media Channel (OTSi Trail)
In a third case, a Network Media Channel terminated on the Filter In a third case, a Network Media Channel is terminated on the Filter
ports of the Ingress and Egress nodes. This is named in G.872 as ports of the Ingress and Egress nodes. This is named in G.872 as
OCh-NC (we need to discuss the implications, if any, once modeled at OTSi Network Connection. As can be seen from the figures, there is
the control plane level of models B and C). no difference from a GMPLS modelling perspective between these cases,
but they are shown as distinct examples to highlight the differences
in the data plane.
|--------------------- Network Media Channel --------------------| |--------------------- Network Media Channel --------------------|
+------------------------+ +------------------------+ +------------------------+ +------------------------+
+------+ +------+ +------+ +------+ +------+ +------+ +------+ +------+
| | +----+ | | | | +----+ | | | | +----+ | | | | +----+ | |
| o-| |-o | +------+ | o-| |-o | | o-| |-o | +------+ | o-| |-o |
| | | | | =====+-+ +-+=====| | | | | | | | | | | =====+-+ +-+=====| | | | | |
T-o******o********************************************************O-R T-o******o********************************************************O-R
| | |\ /| | | | | | | | |\ /| | | | | |\ /| | | | | | | | |\ /| | |
skipping to change at page 17, line 32 skipping to change at page 19, line 32
LSP LSP
LSP LSP
<--------------------------------------------------------------> <-------------------------------------------------------------->
+-----+ +--------+ +-----+ +-----+ +--------+ +-----+
o--| |--------------------| |-------------------| |--o o--| |--------------------| |-------------------| |--o
| LSR | TE link | LSR | TE link | LSR | | LSR | TE link | LSR | TE link | LSR |
| |--------------------| |-------------------| | | |--------------------| |-------------------| |
+-----+ +--------+ +-----+ +-----+ +--------+ +-----+
Figure 13: LSP representing a network media channel (OCh-P NC) Figure 13: LSP Representing a Network Media Channel (OTSi Network
Connection)
[Note: not clear the difference, from a control plane perspective, of
figs Figure 12 and Figure 13.]
Applying the notion of hierarchy at the media layer, by using the LSP Applying the notion of hierarchy at the media layer, by using the LSP
as a FA, the media channel created can support multiple (sub) media as an FA (i.e., by using hierarchical LSPs), the media channel
channels. [Editot note : a specific behavior related to Hierarchies created can support multiple (sub-)media channels.
will be verified at a later point in time].
+--------------+ +--------------+ +--------------+ +--------------+
| OCh-P | TE | OCh-P | Virtual TE | Media Channel| TE | Media Channel| Virtual TE
| | link | | link | | link | | link
| Matrix |o- - - - - - - - - - o| Matrix |o- - - - - - | Matrix |o- - - - - - - - - - o| Matrix |o- - - - - -
+--------------+ +--------------+ +--------------+ +--------------+
| +---------+ | | +---------+ |
| | Media | | | | Media | |
|o----| Channel |-----o| |o----| Channel |-----o|
| | | |
| Matrix | | Matrix |
+---------+ +---------+
Figure 14: MRN/MLN topology view with TE link / FA Figure 14: MRN/MLN Topology View with TE Link / FA
Note that there is only one media layer switch matrix (one Note that there is only one media layer switch matrix (one
implementation is FlexGrid ROADM) in SSON, while "signal layer LSP is implementation is a FlexGrid ROADM) in SSON, while a signal layer LSP
mainly for the purpose of management and control of individual (Network Media Channel) is established mainly for the purpose of
optical signal". Signal layer LSPs (OChs) with the same attributions management and control of individual optical signals. Signal layer
(such as source and destination) could be grouped into one media- LSPs with the same attributes (such as source and destination) can be
layer LSP (media channel), which has advantages in spectral grouped into one media-layer LSP (media channel): this has advantages
efficiency (reduce guard band between adjacent OChs in one FSC) and in spectral efficiency (reduce guard band between adjacent OChs in
LSP management. However, assuming some network elements indeed one FSC channel) and LSP management. However, assuming some network
perform signal layer switch in SSON, there must be enough guard band elements perform signal layer switching in an SSON, there must be
between adjacent OChs in one media channel, in order to compensate enough guard band between adjacent OTSis in any media channel to
filter concatenation effect and other effects caused by signal layer compensate filter concatenation effect and other effects caused by
switching elements. In such condition, the separation of signal signal layer switching elements. In such a situation, the separation
layer from media layer cannot bring any benefit in spectral of the signal layer from the media layer does not bring any benefit
efficiency and in other aspects, but make the network switch and in spectral efficiency or in other aspects, but makes the network
control more complex. If two OChs must switch to different ports, it switch and control more complex. If two OTSis must be switched to
is better to carry them by diferent FSCs and the media layer switch different ports, it is better to carry them by diferent FSC channels,
is enough in this scenario. and the media layer switch is enough in this scenario.
5.4. Control Plane modeling of Network elements As discussed in Section 3.2.5, a media channel may be constructed
from a compsite of network media channels. This may be achieved in
two ways using LSPs. These mechanisms may be compared to the
techniques used in GMPLS to support inverse multiplexing in Time
Division Multiplexing (TDM) networks and in OTN [RFC4606], [RFC6344],
and [RFC7139].
Optical transmitters/receivers may have different tunability o In the first case, a single LSP may be established in the control
plane. The signaling messages include information for all of the
component network media channels that make up the composite media
channel.
o In the second case, each component network media channel is
established using a separate control plane LSP, and these LSPs are
associated within the control plane so that the end points may see
them as a single media channel.
4.4. Control Plane Modeling of Network Elements
Optical transmitters and receivers may have different tunability
constraints, and media channel matrixes may have switching constraints, and media channel matrixes may have switching
restrictions. Additionally, a key feature of their implementation is restrictions. Additionally, a key feature of their implementation is
their highly asymmetric switching capability which is described in their highly asymmetric switching capability which is described in
[RFC6163] in detail. Media matrices include line side ports which detail in [RFC6163]. Media matrices include line side ports that are
are connected to DWDM links and tributary side input/output ports connected to DWDM links, and tributary side input/output ports that
which can be connected to transmitters/receivers. can be connected to transmitters/receivers.
A set of common constraints can be defined: A set of common constraints can be defined:
o The minimum and maximum slot width. o Slot widths: The minimum and maximum slot width.
o Granularity: the optical hardware may not be able to select o Granularity: The optical hardware may not be able to select
parameters with the lowest granularity (e.g. 6.25 GHz for nominal parameters with the lowest granularity (e.g., 6.25 GHz for nominal
central frequencies or 12.5 GHz for slot width granularity). central frequencies or 12.5 GHz for slot width granularity).
o Available frequency ranges: the set or union of frequency ranges o Available frequency ranges: The set or union of frequency ranges
that are not allocated (i.e. available). The relative grouping that have not been allocated (i.e., are available). The relative
and distribution of available frequency ranges in a fiber is grouping and distribution of available frequency ranges in a fiber
usually referred to as ''fragmentation''. is usually referred to as "fragmentation".
o Available slot width ranges: the set or union of slot width ranges o Available slot width ranges: The set or union of slot width ranges
supported by media matrices. It includes the following supported by media matrices. It includes the following
information. information.
* Slot width threshold: the minimum and maximum Slot Width * Slot width threshold: The minimum and maximum Slot Width
supported by the media matrix. For example, the slot width can supported by the media matrix. For example, the slot width
be from 50GHz to 200GHz. could be from 50GHz to 200GHz.
* Step granularity: the minimum step by which the optical filter * Step granularity: The minimum step by which the optical filter
bandwidth of the media matrix can be increased or decreased. bandwidth of the media matrix can be increased or decreased.
This parameter is typically equal to slot width granularity This parameter is typically equal to slot width granularity
(i.e. 12.5GHz) or integer multiples of 12.5GHz. (i.e., 12.5GHz) or integer multiples of 12.5GHz.
[Editor's note: different configurations such as C/CD/CDC will be
added later. This section should state specifics to media channel
matrices, ROADM models need to be moved to an appendix].
5.5. Media Layer Resource Allocation considerations 4.5. Media Layer Resource Allocation Considerations
A media channel has an associated effective frequency slot. From the A media channel has an associated effective frequency slot. From the
perspective of network control and management, this effective slot is perspective of network control and management, this effective slot is
seen as the "usable" frequency slot end to end. The establishment of seen as the "usable" end-to-end frequency slot. The establishment of
an LSP related the establishment of the media channel and effective an LSP is related to the establishment of the media channel and the
frequency slot. configuration of the effective frequency slot.
In this context, when used unqualified, the frequency slot is a local
term, which applies at each hop. An effective frequency slot applies
at the media chall (LSP) level
A "service" request is characterized as a minimum, by its required
effective slot width. This does not preclude that the request may
add additional constraints such as imposing also the nominal central
frequency. A given frequency slot is requested for the media channel
say, with the Path message. Regardless of the actual encoding, the
Path message sender descriptor sender_tspec shall specify a minimum
frequency slot width that needs to be fulfilled.
In order to allocate a proper effective frequency slot for a LSP, the A "service request" is characterized (at a minimum) by its required
signaling should specify its required slot width. effective frequency slot width. This does not preclude that the
request may add additional constraints such as also imposing the
nominal central frequency. A given effective frequency slot may be
requested for the media channel in the control plane LSP setup
messages, and a specific frequency slot can be requeste on any
specific hop of the LSP setup. Regardless of the actual encoding,
the LSP setup message specifies a minimum frequency slot width that
needs to be fulfilled in order to successful establish the requsted
LSP.
An effective frequency slot must equally be described in terms of a An effective frequency slot must equally be described in terms of a
central nominal frequency and its slot width (in terms of usable central nominal frequency and its slot width (in terms of usable
spectrum of the effective frequency slot). That is, one must be able spectrum of the effective frequency slot). That is, it must be
to obtain an end-to-end equivalent n and m parameters. We refer to possible to determine the end-to-end values of the n and m
this as the "effective frequency slot of the media channel/LSP must parameters. We refer to this by saying that the "effective frequency
be valid". slot of the media channel/LSP must be valid".
In GMPLS the requested effective frequency slot is represented to the In GMPLS the requested effective frequency slot is represented to the
TSpec and the effective frequency slot is mapped to the FlowSpec. TSpec present in the Path message, and the effective frequency slot
is mapped to the FlowSpec carried in the Resv message.
The switched element corresponds in GMPLS to the 'label'. As in In GMPLS-controlled systems, the switched element corresponds to the
flexi-grid the switched element is a frequency slot, the label 'label'. In flexi-grid where the switched element is a frequency
represents a frequency slot. Consequently, the label in flexi-grid slot, the label represents a frequency slot. In consequence, the
must convey the necessary information to obtain the frequency slot label in flexi-grid conveys the necessary information to obtain the
characteristics (i.e, center and width, the n and m parameters). The frequency slot characteristics (i.e, central frequency and slot
frequency slot is locally identified by the label width: the n and m parameters). The frequency slot is locally
identified by the label.
The local frequency slot may change at each hop, typically given The local frequency slot may change at each hop, given hardware
hardware constraints (e.g. a given node cannot support the finest constraints and capabilities (e.g., a given node might not support
granularity). Locally n and m may change. As long as a given the finest granularity). This means that the values of n and m may
downstream node allocates enough optical spectrum, m can be different change at each hop. As long as a given downstream node allocates
along the path. This covers the issue where concrete media matrices enough optical spectrum, m can be different along the path. This
can have different slot width granularities. Such "local" m will covers the issue where media matrices can have different slot width
appear in the allocated label that encodes the frequency slot as well granularities. Such variations in the local value of m will appear
as the flow descriptor flowspec. in the allocated label that encodes the frequency slot as well as the
in the FlowSpec that describes the flow.
Different modes are considered: RSA with explicit label control, and Different operational modes can be considered. For Routing and
for R+DSA, the GMPLS signaling procedure is similar to the one Spectrum Assignment (RSA) with explicit label control, and for
described in section 4.1.3 of [RFC6163] except that the label set Routing and Distributed Spectrum Assignment (R+DSA), the GMPLS
should specify the available nominal central frequencies that meet signaling procedures are similar to those described in section 4.1.3
the slot width requirement of the LSP. The intermediate nodes can of [RFC6163] for Routing and Wavelength Assignment (RWA) and for
collect the acceptable central frequencies that meet the slot width Routing and Distributed Wavelength Assignment (R+DWA). The main
requirement hop by hop. The tail-end node also needs to know the difference is that the label set specifies the available nominal
slot width of a LSP to assign the proper frequency resource. central frequencies that meet the slot width requirements of the LSP.
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].
Regarding how a GMPLS control plane can assign n and m, different The intermediate nodes use the control plane to collect the
cases can apply: acceptable central frequencies that meet the slot width requirement
hop by hop. The tail-end node also needs to know the slot width of
an LSP to assign the proper frequency resource. Except for
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 for WSON as described in section 6.1 of
[RFC6163].
a) n and m can both change. It is the effective slot what Regarding how a GMPLS control plane can assign n and m hop-by-hop
matters. Some entity needs to make sure the effective frequency along the path of an LSP, different cases can apply:
slot remains valid.
b) m can change; n needs to be the same along the path. This a. n and m can both change. It is the effective frequency slot that
ensures that the nominal central frequency stays the same. matters, it needs to remain valid along the path.
c) n and m need to be the same. b. m can change, but n needs to remain the same along the path.
This ensures that the nominal central frequency stays the same,
but the width of the slot can vary along the path. Again, the
important thing is that the effective frequency slot remains
valid and satisfies the requested parameters along the whole path
of the LSP.
d)n can change, m needs to be the same. c. n and m need to be unchanging along the path. This ensures that
the frequency slot is well-known end-to-end, and is a simple way
to ensure that the effective frequency slot remains valid for the
whole LSP.
In consequence, an entity such as a PCE can make sure that the n and d. n can change, but m needs to remain the same along the path.
m stay the same along the path. Any constraint (including frequency This ensures that the effective frequency slot remains valid, but
slot and width granularities) is taken into account during path allows the frequency slot to be moved within the spectrum from
computation. alternatively, A PCE (or a source node) can compute a hop to hop.
path and the actual frequency slot assignment is done, for example,
with a distributed (signaling) procedure:
Each downstream node ensures that m is >= requested_m. The selection of a path that ensures n and m continuity can be
delegated to a dedicated entity such as a Path Computation Element
(PCE). Any constraint (including frequency slot and width
granularities) can be taken into account during path computation.
Alternatively, A PCE can compute a path leaving the actual frequency
slot assignment to be done, for example, with a distributed
(signaling) procedure:
Since a downstream node cannot foresee what an upstream node will o Each downstream node ensures that m is >= requested_m.
allocate in turn, a way we can ensure that the effective frequency
slot is valid is then by ensuring that the same "n" is allocated.
By forcing the same n, we avoid cases where the effective
frequency slot of the media channel is invalid (that is, the
resulting frequency slot cannot be described by its n and m
parameters).
Maybe this is a too hard restriction, since a node (or even a o A downstream node cannot foresee what an upstream node will
centralized/combined RSA entity) can make sure that the resulting allocate. A way to ensure that the effective frequency slot is
end to end (effective) frequency slot is valid, even if n is valid along the length of the LSP is to ensure that the same value
different locally. That means, the effective (end to end) of n is allocated at each hop. By forcing the same value of n we
frequency slot that characterizes the media channel is one and avoid cases where the effective frequency slot of the media
determined by its n and m, but are logical, in the sense that they channel is invalid (that is, the resulting frequency slot cannot
are the result of the intersection of local (filters) freq slots be described by its n and m parameters).
which may have different freq. slots
For Figure Figure 15 the effective slot is valid by ensuring that the o This may be too restrictive, since a node (or even a centralized/
combined RSA entity) may be able ensure that the resulting end-to-
end effective frequency slot is valid even if n varies locally.
That means, the effective frequency slot that characterizes the
media channel from end to end is consistent and is determined by
its n and m values, but that the effective frequency slot and
those values are logical (i.e., do not map direct to the
physically assigned spectrum) in the sense that they are the
result of the intersection of locally-assigned frequency slots
applicable at local components (such as filters) each of which may
have assigned different frequency slots.
For Figure 15 the effective slot is made valid by ensuring that the
minimum m is greater than the requested m. The effective slot minimum m is greater than the requested m. The effective slot
(intersection) is the lowest m (bottleneck). (intersection) is the lowest m (bottleneck).
For Figure Figure 16 the effective slot is valid by ensuring that it For Figure 16 the effective slot is made valid by ensuring that it is
is valid at each hop in the upstream direction. The intersection valid at each hop in the upstream direction. The intersection needs
needs to be computed. Invalid slots could result otherwise. to be computed because invalid slots could result otherwise.
|Path(m_req) | ^ | |Path(m_req) | ^ |
|---------> | # | |---------> | # |
| | # ^ | | # ^
-^--------------^----------------#----------------#-- -^--------------^----------------#----------------#--
Effective # # # # Effective # # # #
FS n, m # . . . . . . .#. . . . . . . . # . . . . . . . .# <-fixed FS n, m # . . . . . . .#. . . . . . . . # . . . . . . . .# <-fixed
# # # # n # # # # n
-v--------------v----------------#----------------#--- -v--------------v----------------#----------------#---
| | # v | | # v
| | # Resv | | | # Resv |
| | v <------ | | | v <------ |
| | |flowspec(n, m_a)| | | |FlowSpec(n, m_a)|
| | <--------| | | | <--------| |
| | flowspec (n, | | | FlowSpec (n, |
<--------| min(m_a, m_b)) <--------| min(m_a, m_b))
flowspec (n, | FlowSpec (n, |
min(m_a, m_b, m_c)) min(m_a, m_b, m_c))
Figure 15: Distributed allocation with different m and same n Figure 15: Distributed Allocation with Different m and Same n
|Path(m_req) ^ | |Path(m_req) ^ |
|---------> # | | |---------> # | |
| # ^ ^ | # ^ ^
-^-------------#----------------#-----------------#-------- -^-------------#----------------#-----------------#--------
Effective # # # # Effective # # # #
FS n, m # # # # FS n, m # # # #
# # # # # # # #
-v-------------v----------------#-----------------#-------- -v-------------v----------------#-----------------#--------
| | # v | | # v
| | # Resv | | | # Resv |
| | v <------ | | | v <------ |
| | |flowspec(n_a, m_a) | | |FlowSpec(n_a, m_a)
| | <--------| | | | <--------| |
| | flowspec (FSb [intersect] FSa) | | FlowSpec (FSb [intersect] FSa)
<--------| <--------|
flowspec ([intersect] FSa,FSb,FSc) FlowSpec ([intersect] FSa,FSb,FSc)
Figure 16: Distributed allocation with different m and different n Figure 16: Distributed Allocation with Different m and Different n
Note, when a media channel is bound to one OCh-P (i.e is a Network Note, when a media channel is bound to one OTSi (i.e., is a network
media channel), the EFS must be the one of the Och-P. The media media channel), the EFS must be the one of the OTSi. The media
channel setup by the LSP may contains the EFS of the network media channel setup by the LSP may contains the EFS of the network media
channel EFS. This is an endpoint property, the egress and ingress channel EFS. This is an endpoint property: the egress and ingress
SHOULD constrain the EFS to Och-P EFS . have to constrain the EFS to be the OTSi EFS.
5.6. Neighbor Discovery and Link Property Correlation 4.6. Neighbor Discovery and Link Property Correlation
Potential interworking problems between fixed-grid DWDM and flexible- There are potential interworking problems between fixed-grid DWDM and
grid DWDM nodes, may appear. Additionally, even two flexible-grid flexi-grid DWDM nodes. Additionally, even two flexi-grid nodes may
optical nodes may have different grid properties, leading to link have different grid properties, leading to link property conflict
property conflict. with resulting limited interworking.
Devices or applications that make use of the flexible-grid may not be Devices or applications that make use of the flexi-grid might not be
able to support every possible slot width. In other words, able to support every possible slot width. In other words, different
applications may be defined where different grid granularity can be applications may be defined where each supports a different grid
supported. Taking node F as an example, an application could be granularity. Consider a node with an application where the nominal
defined where the nominal central frequency granularity is 12.5 GHz central frequency granularity is 12.5 GHz and where slot widths are
requiring slot widths being multiple of 25 GHz. Therefore the link multiples of 25 GHz. In this case the link between two optical nodes
between two optical nodes with different grid granularity must be with different grid granularities must be configured to align with
configured to align with the larger of both granularities. Besides, the larger of both granularities. Furthermore, different nodes may
different nodes may have different slot width tuning ranges. have different slot-width tuning ranges.
In summary, in a DWDM Link between two nodes, at least the following In summary, in a DWDM Link between two nodes, at least the following
properties should be negotiated: properties need to be negotiated:
Grid capability (channel spacing) - Between fixed-grid and o Grid capability (channel spacing) - Between fixed-grid and flexi-
flexible-grid nodes. grid nodes.
Grid granularity - Between two flexible-grid nodes. o Grid granularity - Between two flexi-grid nodes.
Slot width tuning range - Between two flexible-grid nodes. o Slot width tuning range - Between two flexi-grid nodes.
5.7. Path Computation / Routing and Spectrum Assignment (RSA) 4.7. Path Computation / Routing and Spectrum Assignment (RSA)
Much like in WSON, in which if there is no (available) wavelength In WSON, if there is no (available) wavelength converter in an
converters in an optical network, an LSP is subject to the optical network, an LSP is subject to the "wavelength continuity
''wavelength continuity constraint'' (see section 4 of [RFC6163]), if constraint" (see section 4 of [RFC6163]). Similarly in flexi-grid,
the capability of shifting or converting an allocated frequency slot, if the capability to shift or convert an allocated frequency slot is
the LSP is subject to the Optical ''Spectrum Continuity Constraint''. absent, the LSP is subject to the "Spectrum Continuity Constraint".
Because of the limited availability of wavelength/spectrum converters Because of the limited availability of wavelength/spectrum converters
(sparse translucent optical network) the wavelength/spectrum (in what is called a "sparse translucent optical network") the
continuity constraint should always be considered. When available, wavelength/spectrum continuity constraint always has to be
information regarding spectrum conversion capabilities at the optical considered. When available, information regarding spectrum
nodes may be used by RSA (Routing and Spectrum Assignment) conversion capabilities at the optical nodes may be used by RSA
mechanisms. mechanisms.
The RSA process determines a route and frequency slot for a LSP. The RSA process determines a route and frequency slot for an LSP.
Hence, when a route is computed the spectrum assignment process (SA) Hence, when a route is computed the spectrum assignment process (SA)
should determine the central frequency and slot width based on the determines the central frequency and slot width based on the slot
slot width and available central frequencies information of the width and available central frequencies information of the
transmitter and receiver, and the available frequency ranges transmitter and receiver, and utilizing the available frequency
information and available slot width ranges of the links that the ranges information and available slot width ranges of the links that
route traverses. the route traverses.
5.7.1. Architectural Approaches to RSA 4.7.1. Architectural Approaches to RSA
Similar to RWA for fixed grids, different ways of performing RSA in Similar to RWA for fixed grids [RFC6163], different ways of
conjunction with the control plane can be considered. The approaches performing RSA in conjunction with the control plane can be
included in this document are provided for reference purposes only; considered. The approaches included in this document are provided
other possible options could also be deployed. for reference purposes only: other possible options could also be
deployed.
5.7.1.1. Combined RSA (R&SA) Note that all of these models allow the concept of a composite media
channel supported by a single control plane LSP or by a set of
associated LSPs.
4.7.1.1. Combined RSA (R&SA)
In this case, a computation entity performs both routing and In this case, a computation entity performs both routing and
frequency slot assignment. The computation entity should have the frequency slot assignment. The computation entity needs access to
detailed network information, e.g. connectivity topology constructed detailed network information, e.g., the connectivity topology of the
by nodes/links information, available frequency ranges on each link, nodes and links, the available frequency ranges on each link, the
node capabilities, etc. node capabilities, etc.
The computation entity could reside either on a PCE or the ingress The computation entity could reside on a dedicated PCE server, in the
provisioning application that requests the service, or on the ingress
node. node.
5.7.1.2. Separated RSA (R+SA) 4.7.1.2. Separated RSA (R+SA)
In this case, routing computation and frequency slot assignment are In this case, routing computation and frequency slot assignment are
performed by different entities. The first entity computes the performed by different entities. The first entity computes the
routes and provides them to the second entity; the second entity routes and provides them to the second entity. The second entity
assigns the frequency slot. assigns the frequency slot.
The first entity should get the connectivity topology to compute the The first entity needs the connectivity topology to compute the
proper routes; the second entity should get the available frequency proper routes. The second entity needs information about the
ranges of the links and nodes' capabilities information to assign the available frequency ranges of the links and the capabilities of the
spectrum. nodes in order to assign the spectrum.
5.7.1.3. Routing and Distributed SA (R+DSA) 4.7.1.3. Routing and Distributed SA (R+DSA)
In this case, one entity computes the route but the frequency slot In this case an entity computes the route, but the frequency slot
assignment is performed hop-by-hop in a distributed way along the assignment is performed hop-by-hop in a distributed way along the
route. The available central frequencies which meet the spectrum route. The available central frequencies which meet the spectrum
continuity constraint should be collected hop by hop along the route. continuity constraint need to be collected hop-by-hop along the
This procedure can be implemented by the GMPLS signaling protocol. route. This procedure can be implemented by the GMPLS signaling
protocol.
5.8. Routing / Topology dissemination 4.8. Routing and Topology Dissemination
In the case of combined RSA architecture, the computation entity In the case of the combined RSA architecture, the computation entity
needs to get the detailed network information, i.e. connectivity needs the detailed network information, i.e., connectivity topology,
topology, node capabilities and available frequency ranges of the node capabilities, and available frequency ranges of the links.
links. Route computation is performed based on the connectivity Route computation is performed based on the connectivity topology and
topology and node capabilities; spectrum assignment is performed node capabilities, while spectrum assignment is performed based on
based on the available frequency ranges of the links. The the available frequency ranges of the links. The computation entity
computation entity may get the detailed network information by the may get the detailed network information via the GMPLS routing
GMPLS routing protocol. Compared with [RFC6163], except wavelength- protocol.
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.
5.8.1. Available Frequency Ranges/slots of DWDM Links For WSON, the connectivity topology and node capabilities can be
advertised by the GMPLS routing protocol (refer to section 6.2 of
[RFC6163]. Except for wavelength-specific availability information,
the information for flexi-grid is the same as for WSON and can
equally be distributed by the GMPLS routing protocol.
This section analyses the necessary changes on link information
brought by flexible grids.
4.8.1. Available Frequency Ranges/Slots of DWDM Links
In the case of flexible grids, channel central frequencies span from 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 193.1 THz towards both ends of the C band spectrum with 6.25 GHz
granularity. Different LSPs could make use of different slot widths granularity. Different LSPs could make use of different slot widths
on the same link. Hence, the available frequency ranges should be on the same link. Hence, the available frequency ranges need to be
advertised. advertised.
5.8.2. Available Slot Width Ranges of DWDM Links 4.8.2. Available Slot Width Ranges of DWDM Links
The available slot width ranges needs to be advertised, in The available slot width ranges need to be advertised in combination
combination with the Available frequency ranges, in order to verify with the available frequency ranges, in order that the computing
whether a LSP with a given slot width can be set up or not; this is entity can verify whether an LSP with a given slot width can be set
is constrained by the available slot width ranges of the media matrix up or not. This is constrained by the available slot width ranges of
Depending on the availability of the slot width ranges, it is the media matrix. Depending on the availability of the slot width
possible to allocate more spectrum than strictly needed by the LSP. ranges, it is possible to allocate more spectrum than strictly needed
by the LSP.
5.8.3. Spectrum Management 4.8.3. Spectrum Management
[Editors' note: the part on the hierarchy of the optical spectrum The total available spectrum on a fiber can be described as a
could be confusing, we can discuss it]. The total available spectrum resource that can be partitioned. For example, a part of the
on a fiber could be described as a resource that can be divided by a spectrum could be assigned to a third party to manage, or parts of
media device into a set of Frequency Slots. In terms of managing the spectrum could be assigned by the operator for different classes
spectrum, it is necessary to be able to speak about different of traffic. This partitioning creates the impression that spectrum
granularities of managed spectrum. For example, a part of the is a hierarchy in view of Management and Control Plane: each
spectrum could be assigned to a third party to manage. This need to partition could be itself be partitioned. However, the hierarchy is
partition creates the impression that spectrum is a hierarchy in view created purely within a management system: it defines a hierarchy of
of Management and Control Plane. The hierarchy is created within a access or management rights, but there is no corresponding resource
management system, and it is an access right hierarchy only. It is a hierarchy within the fiber.
management hierarchy without any actual resource hierarchy within
fiber. The end of fiber is a link end and presents a fiber port
which represents all of spectrum available on the fiber. Each
spectrum allocation appears as Link Channel Port (i.e., frequency
slot port) within fiber.
5.8.4. Information Model The end of fiber is a link end and presents a fiber port which
represents all of spectrum available on the fiber. Each spectrum
allocation appears as Link Channel Port (i.e., frequency slot port)
within fiber. Thus, while there is a hierarchy of ownership (the
Link Channel Port and corresponding LSP are located on a fiber and so
associated with a fiber port) there is no continued nesting hierarchy
of frequency slots within larger frequency slots. In its way, this
mirrors the fixed grid behavior where a wavelength is associated with
a port/fiber, but cannot be subdivided even though it is a partition
of the total spectrum available on the fiber.
Fixed DM grids can also be described via suitable choices of slots in 4.8.4. Information Model
a flexible DWDM grid. However, devices or applications that make use
of the flexible grid may not be capable of supporting every possible This section defines an information model to describe the data that
slot width or central frequency position. Following is the represents the capabilities and resources available in an flexi-grid
definition of information model, not intended to limit any IGP network. It is not a data model and is not intended to limit any
encoding implementation. For example, information required for protocol solution such as an encoding for an IGP. For example,
routing/path selection may be the set of available nominal central information required for routing/path selection may be the set of
frequencies from which a frequency slot of the required width can be available nominal central frequencies from which a frequency slot of
allocated. A convenient encoding for this information (may be as a the required width can be allocated. A convenient encoding for this
frequency slot or sets of contiguous slices) is further study in IGP information is for further study in an IGP encoding document.
encoding document.
Fixed DWDM grids can also be described via suitable choices of slots
in a flexible DWDM grid. However, devices or applications that make
use of the flexible grid may not be capable of supporting every
possible slot width or central frequency position. Thus, the
information model needs to enable:
exchange of information to enable RSA in a flexi-grid network
representation of a fixed grid device participating in a flexi-
grid network
full interworking of fixed and flexible grid devices within the
same network
interworking of flexgrid devices with different capabilities.
The information model is represented using Routing Backus-Naur Format
(RBNF) as defined in [RFC5511].
<Available Spectrum in Fiber for frequency slot> ::= <Available Spectrum in Fiber for frequency slot> ::=
<Available Frequency Range-List> <Available Frequency Range-List>
<Available Central Frequency Granularity > <Available Central Frequency Granularity >
<Available Slot Width Granularity> <Available Slot Width Granularity>
<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 A&#151; 6.25GHz, <Available Central Frequency Granularity> ::= (2^n) x 6.25GHz
where n is positive integer, such as 6.25GHz, 12.5GHz, 25GHz, 50GHz where n is positive integer, giving rise to granularities
or 100GHz such as 6.25GHz, 12.5GHz, 25GHz, 50GHz, and 100GHz
<Available Slot Width Granularity> ::= m A&#151; 12.5GHz, <Available Slot Width Granularity> ::= (2^m) x 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 5. Control Plane Requirements
The GMPLS based control plane of a flexi-grid networks provides The control of a flexi-grid networks places additional requirements
aditional requirements to GMPLS. In this section the features to be on the GMPLS protocols. This section summarizes those requirements
covered by GMPLS signaling for flexi-grid are identified. [Editor's for signaling and routing.
note: Only discussed requirements are included at this stage.
Routing requirements will come in the next version]
6.1. Support for Media Channels 5.1. Support for Media Channels
The control plane SHALL be able to support Media Channels, The control plane SHALL be able to support Media Channels,
characterized by a single frequency slot. The representation of the characterized by a single frequency slot. The representation of the
Media Channel in the GMPLS Control plane is the so-called flexi-grid Media Channel in the GMPLS control plane is the so-called flexi-grid
LSP. Since network media channels are media channels, an LSP may LSP. Since network media channels are media channels, an LSP may
also be the control plane representation of a network media channel. also be the control plane representation of a network media channel.
Consequently, the control plane SHALL be able to support Network Consequently, the control plane will also be able to support Network
Media Channels. Media Channels.
5.1.1. Signaling
The signaling procedure SHALL be able to configure the nominal The signaling procedure SHALL be able to configure the nominal
central frequency (n) of a flexi-grid LSP. central frequency (n) of a flexi-grid LSP.
The control plane protocols SHALL allow flexible range of values for The signaling procedure SHALL allow a flexible range of values for
the frequency slot width (m) parameter. Specifically, the control the frequency slot width (m) parameter. Specifically, the control
plane SHALL allow setting up a media channel with frequency slot 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 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. entire C-band with a slot width granularity of 12.5GHz.
The signaling procedure of the GMPLS control plane SHALL be able to The signaling procedure SHALL be able to configure the minimum width
configure the minimum width (m) of a flexi-grid LSP. In adition, the (m) of a flexi-grid LSP. In addition, the signaling procedure SHALL
control plane SHALL be able to configure local frecuency slots, be able to configure local frequency slots.
The control plane architecture SHOULD allow for the support of L-band The control plane architecture SHOULD allow for the support of L-band
and S-band and S-band.
The signalling process of the control plane SHALL allow to collect The signalling process SHALL be able to collect the local frequency
the local frequency slot asigned at each link along the path slot assigned at each link along the path.
6.2. Support for Media Channel Resizing The signaling procedures SHALL support all of the RSA architectural
models (R&SA, R+SA, and R+DSA) within a single set of protocol
objects although some objects may only be applicable within on of the
models.
The control plane SHALL allow resizing (grow or shrink) the frequency 5.1.2. Routing
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.
6.3. Support for Logical Associations of multiple media channels The routing protocol will support all functions as described in
[RFC4202] and extend them to a flexi-grid data plane.
The routing protocol SHALL distribute sufficient information to
compute paths to enable the signaling procedure to establish LSPs as
described in the previous sections. This includes, at a minimum the
data described by the Information Model in Figure 17.
The routing protocol SHALL update its advertisements of available
resources and capabilities as the usage of resources in the network
varies with the establishment or tear-down of LSPs. These updates
SHOULD be amenable to damping and thresholds as in other traffic
engineering routing advertisements.
The routing protocol SHALL support all of the RSA architectural
models (R&SA, R+SA, and R+DSA) without any configuration or change of
behavior. Thus, the routing protocols SHALL be agnostic to the
computation and signaling model that is in use.
5.2. Support for Media Channel Resizing
The signaling procedures SHALL allow resizing (grow or shrink) the
frequency 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.
The routing protocol SHALL update its advertisements of available
resources and capabilities as the usage of resources in the network
varies with the resizing of LSP. These updates SHOULD be amenable to
damping and thresholds as in other traffic engineering routing
advertisements.
5.3. Support for Logical Associations of Multiple Media Channels
A set of media channels can be used to transport signals that have a A set of media channels can be used to transport signals that have a
logical association between them. The control plane architecture logical association between them. The control plane architecture
SHOULD allow multiple media channels to be logically associated. The SHOULD allow multiple media channels to be logically associated. The
control plane SHOULD allow the co-routing of a set of media channels control plane SHOULD allow the co-routing of a set of media channels
logically associated that are logically associated.
5.4. Support for Composite Media Channels
As described in Section 3.2.5 and Section 4.3, a media channel may be
composed of multiple network media channels.
The signaling procedures SHOULD include support for signaling a
single control plane LSP that includes information about multiple
network media channels that will comprise the single compound media
channel.
The signaling procedures SHOULD include a mechanism to associate
separately signaled control plane LSPs so that the end points may
correlate them into a single compound media channel.
The signaling procedures MAY include a mechanism to dynamically vary
the composition of a composite media channel by allowing network
media channels to be added to or removed from the whole.
The routing protocols MUST provide sufficient information for the
computation of paths and slots for composite media channels using any
of the three RSA architectural models (R&SA, R+SA, and R+DSA).
5.5. Support for Neighbor Discovery and Link Property Correlation
The control plane MAY include support for neighbor discovery such
that an flexi-grid network can be constructed in a "plug-and-play"
manner.
The control plane SHOULD allow the nodes at opposite ends of a link
to correlate the properties that they will apply to the link. Such
correlation SHOULD include at least the identities of the node and
the identities they apply to the link. Other properties such as the
link characteristics described for the routing information model in
Figure 17 SHOULD also be correlated.
Such neighbor discovery and link property correlation, if provided,
MUST be able to operate in both an out-of-band and an out-of-fiber
control channel.
6. IANA Considerations
This framework document makes no requests for IANA action.
7. Security Considerations 7. Security Considerations
TBD The control plane and data plane aspects of a flexi-grid system are
fundamentally the same as a fixed grid system and there is no
substantial reason to expect the security considerations to be any
different.
8. Contributing Authors A good overview of the security considerations for a GMPLS-based
control plane can be found in [RFC5920].
Qilei Wang [RFC6163] includes a section describing security considerations for
ZTE WSON, and it is reasonable to infer that these considerations apply
Ruanjian Avenue, Nanjing, China and may be exacerbated in a flexi-grid SSON system. In particular,
wang.qilei@zte.com.cn the detailed and granular information describing a flexi- grid
network and the capabilities of nodes in that network could put
stress on the routing protocol or the out-of-band control channel
used by the protocol. An attacker might be able to cause small
variations in the use of the network or the available resources
(perhaps by modifying the environment of a fiber) and so trigger the
routing protocol to make new flooding announcements. This situation
is explicitly mitigated in the requirements for the routing protocol
extensions where it is noted that the protocol must include damping
and configurable thresholds as already exist in the core GMPLS
routing protocols.
Malcolm Betts 8. Manageability Considerations
ZTE
malcolm.betts@zte.com.cn GMPLS systems already contain a number of management tools.
o MIB modules exist to model the control plane protocols and the
network elements [RFC4802], [RFC4803], and there is early work to
provide similar access through YANG. The features described in
these models are currently designed to represent fixed-label
technologies such as optical networks using the fixed grid:
extensions may be needed in order to represent bandwidth,
frequency slots, and effective frequency slots in flexi- grid
networks.
o There are protocol extensions within GMPLS signaling to allow
control plane systems to report the presence of faults that affect
LSPs [RFC4783], although it must be carefully noted that these
mechanisms do not constitute an alarm mechanism that could be used
to rapidly propagate information about faults in a way that would
allow the data plane to perform protection switching. These
mechanisms could easily be enhanced with the addition of
technology-specific reasons codes if any are needed.
o The GMPLS protocols, themselves, already include fault detection
and recovery mechanisms (such as the PathErr and Notify messages
in RSVP-TE signaling as used by GMPLS [RFC3473]. It is not
anticipated that these mechanisms will need enhancement to support
flexi-grid although additional reason codes may be needed to
describe technology-specific error cases.
o [RFC7260] describes a framework for the control and configuration
of data plane Operations, Administration, and Management (OAM).
It would not be appropriate for the IETF to define or describe
data plane OAM for optical systems, but the framework described in
RFC 7260 could be used (with minor protocol extensions) to enable
data plane OAM that has been defined by the originators of the
flexi-grid data plane technology (the ITU-T).
o The Link Management Protocol [RFC4204] is designed to allow the
two ends of a network link to coordinate and confirm the
configuration and capabilities that they will apply to the link.
This protocol is particularly applicable to optical links where
the characteristics of the network devices may considerably affect
how the link is used and where misconfiguration of mis-fibering
could make physical interoperability impossible. LMP could easily
be extended to collect and report information between the end
points of links in a flexi-grid network.
9. Contributing Authors
Adrian Farrel
Old Dog Consulting
adrian@olddog.co.uk
Daniel King
Old Dog Consulting
daniel@olddog.co.uk
Xian Zhang Xian Zhang
Huawei Huawei
zhang.xian@huawei.com zhang.xian@huawei.com
Cyril Margaria Cyril Margaria
Juniper Networks Juniper Networks
cmargaria@juniper.net cmargaria@juniper.net
Qilei Wang
ZTE
Ruanjian Avenue, Nanjing, China
wang.qilei@zte.com.cn
Malcolm Betts
ZTE
malcolm.betts@zte.com.cn
Sergio Belotti Sergio Belotti
Alcatel Lucent Alcatel Lucent
Optics CTO Optics CTO
Via Trento 30 20059 Vimercate (Milano) Italy Via Trento 30 20059 Vimercate (Milano) Italy
+39 039 6863033 +39 039 6863033
sergio.belotti@alcatel-lucent.com sergio.belotti@alcatel-lucent.com
Yao Li Yao Li
Nanjing University Nanjing University
wsliguotou@hotmail.com wsliguotou@hotmail.com
skipping to change at page 29, line 25 skipping to change at page 36, line 15
China Academy of Telecom Research China Academy of Telecom Research
No.52 Huayuan Bei Road, Beijing, China No.52 Huayuan Bei Road, Beijing, China
zhangguoying@ritt.cn zhangguoying@ritt.cn
Takehiro Tsuritani Takehiro Tsuritani
KDDI R&D Laboratories Inc. KDDI R&D Laboratories Inc.
2-1-15 Ohara, Fujimino, Saitama, Japan 2-1-15 Ohara, Fujimino, Saitama, Japan
tsuri@kddilabs.jp tsuri@kddilabs.jp
Lei Liu Lei Liu
KDDI R&D Laboratories Inc. U.C. Davis, USA
2-1-15 Ohara, Fujimino, Saitama, Japan leiliu@ucdavis.edu
le-liu@kddilabs.jp
Eve Varma Eve Varma
Alcatel-Lucent Alcatel-Lucent
+1 732 239 7656 +1 732 239 7656
eve.varma@alcatel-lucent.com eve.varma@alcatel-lucent.com
Young Lee Young Lee
Huawei Huawei
Jianrui Han Jianrui Han
skipping to change at page 30, line 17 skipping to change at page 37, line 7
Marco Sosa Marco Sosa
Infinera Infinera
Biao Lu Biao Lu
Infinera Infinera
Abinder Dhillon Abinder Dhillon
Infinera Infinera
Felipe Jimenez Arribas Felipe Jimenez Arribas
TelefA^3nica I+D Telefonica I+D
Andrew G. Malis Andrew G. Malis
Verizon Huawei
agmalis@gmail.com
Adrian Farrel
Old Dog Consulting
Daniel King
Old Dog Consulting
Huub van Helvoort Huub van Helvoort
Hai Gaoming BV
The Neterlands
huubatwork@gmail.com
9. Acknowledgments 10. 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. This work was supported in part by the FP-7 IDEALIST clarifications.
project under grant agreement number 317999.
10. References This work was supported in part by the FP-7 IDEALIST project under
grant agreement number 317999.
10.1. Normative References 11. References
11.1. 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
Recommendation G.709, Interfaces for the Optical Transport
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
Recommendation G.8080/Y.1304, Architecture for the Recommendation G.8080/Y.1304, Architecture for the
skipping to change at page 31, line 37 skipping to change at page 38, line 21
networks, draft v0.16 2012/09 (for discussion)", 2012. networks, draft v0.16 2012/09 (for discussion)", 2012.
[G.959.1-2013] [G.959.1-2013]
International Telecomunications Union, "Update of ITU-T International Telecomunications Union, "Update of ITU-T
Recommendation G.959.1, Optical transport network physical Recommendation G.959.1, Optical transport network physical
layer interfaces (to appear in July 2013)", 2013. layer interfaces (to appear in July 2013)", 2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3945] Mannie, E., "Generalized Multi-Protocol Label Switching [RFC4202] Kompella, K. and Y. Rekhter, "Routing Extensions in
(GMPLS) Architecture", RFC 3945, October 2004. Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4202, October 2005.
[RFC4206] Kompella, K. and Y. Rekhter, "Label Switched Paths (LSP) [RFC4206] Kompella, K. and Y. Rekhter, "Label Switched Paths (LSP)
Hierarchy with Generalized Multi-Protocol Label Switching Hierarchy with Generalized Multi-Protocol Label Switching
(GMPLS) Traffic Engineering (TE)", RFC 4206, October 2005. (GMPLS) Traffic Engineering (TE)", RFC 4206, October 2005.
[RFC5150] Ayyangar, A., Kompella, K., Vasseur, JP., and A. Farrel, [RFC5511] Farrel, A., "Routing Backus-Naur Form (RBNF): A Syntax
"Label Switched Path Stitching with Generalized Used to Form Encoding Rules in Various Routing Protocol
Multiprotocol Label Switching Traffic Engineering (GMPLS Specifications", RFC 5511, April 2009.
TE)", RFC 5150, February 2008.
[RFC6163] Lee, Y., Bernstein, G., and W. Imajuku, "Framework for 11.2. Informative References
GMPLS and Path Computation Element (PCE) Control of
Wavelength Switched Optical Networks (WSONs)", RFC 6163,
April 2011.
10.2. Informative References [RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Resource ReserVation Protocol-Traffic
Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.
[RFC4204] Lang, J., "Link Management Protocol (LMP)", RFC 4204,
October 2005.
[RFC4397] Bryskin, I. and A. Farrel, "A Lexicography for the [RFC4397] Bryskin, I. and A. Farrel, "A Lexicography for the
Interpretation of Generalized Multiprotocol Label Interpretation of Generalized Multiprotocol Label
Switching (GMPLS) Terminology within the Context of the Switching (GMPLS) Terminology within the Context of the
ITU-T's Automatically Switched Optical Network (ASON) ITU-T's Automatically Switched Optical Network (ASON)
Architecture", RFC 4397, February 2006. Architecture", RFC 4397, February 2006.
[RFC4606] Mannie, E. and D. Papadimitriou, "Generalized Multi-
Protocol Label Switching (GMPLS) Extensions for
Synchronous Optical Network (SONET) and Synchronous
Digital Hierarchy (SDH) Control", RFC 4606, August 2006.
[RFC4783] Berger, L., "GMPLS - Communication of Alarm Information",
RFC 4783, December 2006.
[RFC4802] Nadeau, T. and A. Farrel, "Generalized Multiprotocol Label
Switching (GMPLS) Traffic Engineering Management
Information Base", RFC 4802, February 2007.
[RFC4803] Nadeau, T. and A. Farrel, "Generalized Multiprotocol Label
Switching (GMPLS) Label Switching Router (LSR) Management
Information Base", RFC 4803, February 2007.
[RFC5920] Fang, L., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, July 2010.
[RFC6163] Lee, Y., Bernstein, G., and W. Imajuku, "Framework for
GMPLS and Path Computation Element (PCE) Control of
Wavelength Switched Optical Networks (WSONs)", RFC 6163,
April 2011.
[RFC6344] Bernstein, G., Caviglia, D., Rabbat, R., and H. van
Helvoort, "Operating Virtual Concatenation (VCAT) and the
Link Capacity Adjustment Scheme (LCAS) with Generalized
Multi-Protocol Label Switching (GMPLS)", RFC 6344, August
2011.
[RFC7139] Zhang, F., Zhang, G., Belotti, S., Ceccarelli, D., and K.
Pithewan, "GMPLS Signaling Extensions for Control of
Evolving G.709 Optical Transport Networks", RFC 7139,
March 2014.
[RFC7260] Takacs, A., Fedyk, D., and J. He, "GMPLS RSVP-TE
Extensions for Operations, Administration, and Maintenance
(OAM) Configuration", RFC 7260, June 2014.
Authors' Addresses Authors' Addresses
Oscar Gonzalez de Dios (editor) Oscar Gonzalez de Dios (editor)
Telefonica I+D Telefonica I+D
Don Ramon de la Cruz 82-84 Don Ramon de la Cruz 82-84
Madrid 28045 Madrid 28045
Spain Spain
Phone: +34913128832 Phone: +34913128832
Email: oscar.gonzalezdedios@telefonica.com Email: oscar.gonzalezdedios@telefonica.com
skipping to change at page 32, line 44 skipping to change at page 40, line 24
Huawei Huawei
Huawei Base, Bantian, Longgang District Huawei Base, Bantian, Longgang District
Shenzhen 518129 Shenzhen 518129
China China
Phone: +86-755-28972912 Phone: +86-755-28972912
Email: zhangfatai@huawei.com Email: zhangfatai@huawei.com
Xihua Fu Xihua Fu
ZTE ZTE
Ruanjian Avenue ZTE Plaza,No.10,Tangyan South Road, Gaoxin District
Nanjing Xi'An
China China
Email: fu.xihua@zte.com.cn Email: fu.xihua@zte.com.cn
Daniele Ceccarelli Daniele Ceccarelli
Ericsson Ericsson
Via Calda 5 Via Calda 5
Genova Genova
Italy Italy
Phone: +39 010 600 2512 Phone: +39 010 600 2512
Email: daniele.ceccarelli@ericsson.com Email: daniele.ceccarelli@ericsson.com
Iftekhar Hussain Iftekhar Hussain
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