draft-ietf-ccamp-flexi-grid-fwk-05.txt   draft-ietf-ccamp-flexi-grid-fwk-06.txt 
CCAMP Working Group O. Gonzalez de Dios, Ed. CCAMP Working Group O. Gonzalez de Dios, Ed.
Internet-Draft Telefonica I+D Internet-Draft Telefonica I+D
Intended status: Informational R. Casellas, Ed. Intended status: Informational R. Casellas, Ed.
Expires: November 26, 2015 CTTC Expires: February 26, 2016 CTTC
May 25, 2015 August 25, 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-05 draft-ietf-ccamp-flexi-grid-fwk-06
Abstract Abstract
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 its Telecommunication Standardization Sector (ITU-T) has extended its
Recommendations G.694.1 and G.872 to include a new dense wavelength Recommendations G.694.1 and G.872 to include a new dense wavelength
division multiplexing (DWDM) grid by defining a set of nominal division multiplexing (DWDM) grid by defining a set of nominal
central frequencies, channel spacings and the concept of "frequency central frequencies, channel spacings and the concept of "frequency
slot". In such an environment, a data plane connection is switched slot". In such an environment, a data plane connection is switched
based on allocated, variable-sized frequency ranges within the based on allocated, variable-sized frequency ranges within the
optical spectrum creating what is known as a flexible grid (flexi- optical spectrum creating what is known as a flexible grid (flexi-
grid). grid).
This document defines a framework and the associated control plane Given the specific characteristics of flexi-grid optical networks and
requirements for the GMPLS-based control of flexi-grid DWDM networks. their associated technology, this document defines a framework and
the associated control plane requirements for the application of the
existing GMPLS architecture and control plane protocols to the
control of flexi-grid DWDM networks. The actual extensions to the
GMPLS protocols will be defined in companion documents.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 26, 2015. This Internet-Draft will expire on February 26, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 50 skipping to change at page 2, line 50
4.3. Consideration of LSPs in Flexi-grid . . . . . . . . . . . 15 4.3. Consideration of LSPs in Flexi-grid . . . . . . . . . . . 15
4.4. Control Plane Modeling of Network Elements . . . . . . . 20 4.4. Control Plane Modeling of Network Elements . . . . . . . 20
4.5. Media Layer Resource Allocation Considerations . . . . . 20 4.5. Media Layer Resource Allocation Considerations . . . . . 20
4.6. Neighbor Discovery and Link Property Correlation . . . . 24 4.6. Neighbor Discovery and Link Property Correlation . . . . 24
4.7. Path Computation / Routing and Spectrum Assignment (RSA) 25 4.7. Path Computation / Routing and Spectrum Assignment (RSA) 25
4.7.1. Architectural Approaches to RSA . . . . . . . . . . . 25 4.7.1. Architectural Approaches to RSA . . . . . . . . . . . 25
4.8. Routing and Topology Dissemination . . . . . . . . . . . 26 4.8. Routing and Topology Dissemination . . . . . . . . . . . 26
4.8.1. Available Frequency Ranges/Slots of DWDM Links . . . 27 4.8.1. Available Frequency Ranges/Slots of DWDM Links . . . 27
4.8.2. Available Slot Width Ranges of DWDM Links . . . . . . 27 4.8.2. Available Slot Width Ranges of DWDM Links . . . . . . 27
4.8.3. Spectrum Management . . . . . . . . . . . . . . . . . 27 4.8.3. Spectrum Management . . . . . . . . . . . . . . . . . 27
4.8.4. Information Model . . . . . . . . . . . . . . . . . . 27 4.8.4. Information Model . . . . . . . . . . . . . . . . . . 28
5. Control Plane Requirements . . . . . . . . . . . . . . . . . 29 5. Control Plane Requirements . . . . . . . . . . . . . . . . . 29
5.1. Support for Media Channels . . . . . . . . . . . . . . . 29 5.1. Support for Media Channels . . . . . . . . . . . . . . . 29
5.1.1. Signaling . . . . . . . . . . . . . . . . . . . . . . 30 5.1.1. Signaling . . . . . . . . . . . . . . . . . . . . . . 30
5.1.2. Routing . . . . . . . . . . . . . . . . . . . . . . . 30 5.1.2. Routing . . . . . . . . . . . . . . . . . . . . . . . 30
5.2. Support for Media Channel Resizing . . . . . . . . . . . 31 5.2. Support for Media Channel Resizing . . . . . . . . . . . 31
5.3. Support for Logical Associations of Multiple Media 5.3. Support for Logical Associations of Multiple Media
Channels . . . . . . . . . . . . . . . . . . . . . . . . 31 Channels . . . . . . . . . . . . . . . . . . . . . . . . 31
5.4. Support for Composite Media Channels . . . . . . . . . . 31 5.4. Support for Composite Media Channels . . . . . . . . . . 31
5.5. Support for Neighbor Discovery and Link Property 5.5. Support for Neighbor Discovery and Link Property
Correlation . . . . . . . . . . . . . . . . . . . . . . . 32 Correlation . . . . . . . . . . . . . . . . . . . . . . . 32
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 32 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 32
7. Security Considerations . . . . . . . . . . . . . . . . . . . 32 7. Security Considerations . . . . . . . . . . . . . . . . . . . 32
8. Manageability Considerations . . . . . . . . . . . . . . . . 33 8. Manageability Considerations . . . . . . . . . . . . . . . . 33
9. Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 9. Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
10. Contributing Authors . . . . . . . . . . . . . . . . . . . . 34 10. Contributing Authors . . . . . . . . . . . . . . . . . . . . 34
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 37 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 37
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 37 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 37
12.1. Normative References . . . . . . . . . . . . . . . . . . 37 12.1. Normative References . . . . . . . . . . . . . . . . . . 37
12.2. Informative References . . . . . . . . . . . . . . . . . 38 12.2. Informative References . . . . . . . . . . . . . . . . . 38
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 39 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40
1. 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
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The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
While [RFC2119] describes interpretations of these key words in terms While [RFC2119] describes interpretations of these key words in terms
of protocol specifications and implementations, they are used in this of protocol specifications and implementations, they are used in this
document to describe design requirements for protocol extensions. document to describe design requirements for protocol extensions.
2.2. Abbreviations 2.2. Abbreviations
EFS: Effective Frequency Slot
FS: Frequency Slot FS: Frequency Slot
FSC: Fiber-Switch Capable FSC: Fiber-Switch Capable
LSR: Label Switching Router 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
OTN: Optical Transport Network
OTN: Optical Transport Network
OTSi: Optical Tributary Signal OTSi: Optical Tributary Signal
OTSiG: OTSi Group is a set of OTSi OTSiG: OTSi Group is a set of OTSi
OCC: Optical Channel Carrier OCC: Optical Channel Carrier
PCE: Path Computation Element PCE: Path Computation Element
ROADM: Reconfigurable Optical Add-Drop Multiplexer ROADM: Reconfigurable Optical Add-Drop Multiplexer
skipping to change at page 7, line 14 skipping to change at page 7, line 14
axis. A slot width is constrained to be m x SWG (that is, m x 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. 12.5 GHz), where m is an integer greater than or equal to 1.
Frequency Slot 1 Frequency Slot 2 Frequency Slot 1 Frequency Slot 2
------------- ------------------- ------------- -------------------
| | | | | | | |
-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
...--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--... ...--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--...
------------- ------------------- ------------- -------------------
^ ^ ^ ^
Central F = 193.1THz Central F = 193.14375 THz Slot NCF = 193.1THz Slot NCF = 193.14375 THz
Slot width = 25 GHz Slot width = 37.5 GHz Slot width = 25 GHz Slot width = 37.5 GHz
n=0, m=2 n=7, m=3
Figure 3: Example Frequency Slots Figure 3: Example Frequency Slots
* The symbol '+' represents the allowed nominal central * The symbol '+' represents the allowed nominal central
frequencies frequencies
* The '--' represents the nominal central frequency granularity * The '--' represents the nominal central frequency granularity
in units of 6.25 GHz
* The '^' represents the slot nominal central frequency * The '^' represents the slot nominal central frequency
* The number on the top of the '+' symbol represents the 'n' in * The number on the top of the '+' symbol represents the 'n' in
the frequency calculation formula. the frequency calculation formula.
* The nominal central frequency is 193.1 THz when n equals to * The nominal central frequency is 193.1 THz when n equals to
zero. zero.
o Effective Frequency Slot [G.870]: The effective frequency slot of o Effective Frequency Slot [G.870]: The effective frequency slot of
a media channel is that part of the frequency slots of the filters a media channel is that part of the frequency slots of the filters
along the media channel that is common to all of the filters' along the media channel that is common to all of the filters'
frequency slots. Note that both the Frequency Slot and Effective frequency slots. Note that both the Frequency Slot and Effective
Frequency Slot are local terms. Frequency Slot are local terms.
Frequency Slot 1 o Figure 4 shows the effect of combining two filters along a
channel. The combination of frequency slot 1 and frequency slot 2
applied to the media channel is effective frequency slot shown.
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
------------------- -------------------
| | | |
-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--+--+--+--+--+--+--+--+--+--+--+--...
=============================================== ===============================================
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
skipping to change at page 9, line 47 skipping to change at page 9, line 47
(i.e., there is no spectrum between them that can be used for (i.e., there is no spectrum between them that can be used for
other media channels) or non-contiguous. other media channels) or non-contiguous.
o It is not currently envisaged that such composite media channels o It is not currently envisaged that such composite media channels
may be constructed from slots carried on different fibers whether may be constructed from slots carried on different fibers whether
those fibers traverse the same hop-by-hop path through the network those fibers traverse the same hop-by-hop path through the network
or not. or not.
o Furthermore, it is not considered likely that a media channel may o Furthermore, it is not considered likely that a media channel may
be constructed from a different variation of slot composition on be constructed from a different variation of slot composition on
each hop. That is, the slot composition must be the same from one each hop. That is, the slot composition (i.e., the group of OTSi
end to the other of the media channel even if the specific slots carried by the composite media channel) must be the same from one
and their spacing may vary hop by hop. end to the other of the media channel even if the specific slot
for each OTSi and the spacing among slots may vary hop by hop.
o How the signal is carried across such groups of network media o How the signal is carried across such groups of network media
channels is out of scope for this document. channels is out of scope for this document.
3.3. Hierarchy in the Media Layer 3.3. Hierarchy in the Media Layer
In summary, the concept of frequency slot is a logical abstraction In summary, the concept of frequency slot is a logical abstraction
that represents a frequency range, while the media layer represents that represents a frequency range, while the media layer represents
the underlying media support. Media Channels are media associations, the underlying media support. Media Channels are media associations,
characterized by their (effective) frequency slot, respectively; and characterized by their (effective) frequency slot, respectively; and
skipping to change at page 10, line 25 skipping to change at page 10, line 25
control and management perspective, a media channel can be logically control and management perspective, a media channel can be logically
split into network media channels. split into network media channels.
In Figure 5, a media channel has been configured and dimensioned to In Figure 5, a media channel has been configured and dimensioned to
support two network media channels, each of them carrying one OTSi. support two network media channels, each of them carrying one OTSi.
Media Channel Frequency Slot Media Channel Frequency Slot
+-------------------------------X------------------------------+ +-------------------------------X------------------------------+
| | | |
| Frequency Slot Frequency Slot | | Frequency Slot Frequency Slot |
| +------------X----------+ +----------X-----------+ | | +-----------X-----------+ +----------X-----------+ |
| | OTSi | | OTSi | | | | OTSi | | OTSi | |
| | o | | o | | | | o | | o | |
| | | | | | | | | | | | | | | |
-4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12
--+---+---+---+---+---+---+---+---+---+---+---+--+---+---+---+---+-- --+---+---+---+---+---+---+---+---+---+---+---+--+---+---+---+---+--
<- Network Media Channel-> <- Network Media Channel-> <- Network Media Channel-> <- Network Media Channel->
<------------------------ Media Channel -----------------------> <------------------------ Media Channel ----------------------->
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networks are covered in Section 5. This framework is aimed at networks are covered in Section 5. This framework is aimed at
controlling the media layer within the OTN hierarchy, and controlling controlling the media layer within the OTN hierarchy, and controlling
the required adaptations of the signal layer. This document also the required adaptations of the signal layer. This document also
defines the term Spectrum-Switched Optical Network (SSON) to refer to defines the term Spectrum-Switched Optical Network (SSON) to refer to
a Flexi-grid enabled DWDM network that is controlled by a GMPLS/PCE a Flexi-grid enabled DWDM network that is controlled by a GMPLS/PCE
control plane. 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, as defined in
[RFC3945]).
4.1. 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 that are switched in media channel matrices. GMPLS media channels that are switched in media channel matrices. GMPLS
labels are used to locally represent the media channel and its labels are used to locally represent the media channel and its
associated frequency slot. Network media channels are considered a associated frequency slot. Network media channels are considered a
particular case of media channels when the end points are particular case of media channels when the end points are
transceivers (that is, source and destination of an OTSi). transceivers (that is, source and destination of an OTSi).
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|------------------| |----------------| |------------------| |----------------|
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 network side of the trnaponders. This is commonly names as OTSi- the network side of the transceivers. This is commonly named an
trail connection. OTSi-trail connection.
|--------------------- Network Media Channel ----------------------| |--------------------- Network Media Channel ----------------------|
+----------------------+ +----------------------+ +----------------------+ +----------------------+
| | | | | |
+------+ +------+ +------+ +------+ +------+ +------+ +------+ +------+
| | +----+ | | | | +----+ | |OTSi | | +----+ | | | | +----+ | |OTSi
OTSi| o-| |-o | +-----+ | o-| |-o |sink OTSi| o-| |-o | +-----+ | o-| |-o |sink
src | | | | | ===+-+ +-+==| | | | | O---|R src | | | | | ===+-+ +-+==| | | | | O---|R
T|***o******o******************************************************** T|***o******o********************************************************
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perspective of network control and management, this effective slot is perspective of network control and management, this effective slot is
seen as the "usable" end-to-end frequency slot. The establishment of seen as the "usable" end-to-end frequency slot. The establishment of
an LSP is related to the establishment of the media channel and the an LSP is related to the establishment of the media channel and the
configuration of the effective frequency slot. configuration of the effective frequency slot.
A "service request" is characterized (at a minimum) by its required A "service request" is characterized (at a minimum) by its required
effective frequency slot width. This does not preclude that the effective frequency slot width. This does not preclude that the
request may add additional constraints such as also imposing the request may add additional constraints such as also imposing the
nominal central frequency. A given effective frequency slot may be nominal central frequency. A given effective frequency slot may be
requested for the media channel in the control plane LSP setup requested for the media channel in the control plane LSP setup
messages, and a specific frequency slot can be requeste on any messages, and a specific frequency slot can be requested on any
specific hop of the LSP setup. Regardless of the actual encoding, specific hop of the LSP setup. Regardless of the actual encoding,
the LSP setup message specifies a minimum frequency slot width that the LSP setup message specifies a minimum effective frequency slot
needs to be fulfilled in order to successful establish the requsted width that needs to be fulfilled in order to successful establish the
LSP. 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, it must be spectrum of the effective frequency slot). That is, it must be
possible to determine the end-to-end values of the n and m possible to determine the end-to-end values of the n and m
parameters. We refer to this by saying that the "effective frequency parameters. We refer to this by saying that the "effective frequency
slot of the media channel/LSP must 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 present in the Path message, and the effective frequency slot TSpec present in the RSVP-TE Path message, and the effective
is mapped to the FlowSpec carried in the Resv message. frequency slot is mapped to the FlowSpec carried in the RSVP-TE Resv
message.
In GMPLS-controlled systems, the switched element corresponds to the In GMPLS-controlled systems, the switched element corresponds to the
'label'. In flexi-grid where the switched element is a frequency 'label'. In flexi-grid where the switched element is a frequency
slot, the label represents a frequency slot. In consequence, the slot, the label represents a frequency slot. In consequence, the
label in flexi-grid conveys the necessary information to obtain the label in flexi-grid conveys the necessary information to obtain the
frequency slot characteristics (i.e, central frequency and slot frequency slot characteristics (i.e, central frequency and slot
width: the n and m parameters). The frequency slot is locally width: the n and m parameters). The frequency slot is locally
identified by the label. identified by the label.
The local frequency slot may change at each hop, given hardware The local frequency slot may change at each hop, given hardware
skipping to change at page 23, line 27 skipping to change at page 23, line 28
have assigned different frequency slots. have assigned different frequency slots.
For Figure 15 the effective slot is made valid by ensuring that the 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 16 the effective slot is made valid by ensuring that it is For Figure 16 the effective slot is made valid by ensuring that it is
valid at each hop in the upstream direction. The intersection needs valid at each hop in the upstream direction. The intersection needs
to be computed because invalid slots could result otherwise. to be computed because invalid slots could result otherwise.
C B A
|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))
m_a, m_b, m_c: Selected frequency slot widths
Figure 15: Distributed Allocation with Different m and Same n Figure 15: Distributed Allocation with Different m and Same n
|Path(m_req) ^ | C B A
|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)
n_a: Selected nominal central frequencyfr by node A
m_a: Selected frequency slot widths by node A
FSa, FSb, FSc: Frequency slot at each hop A, B, C
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 OTSi (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 OTSi. The media media channel), the effective FS must be the one of the OTSi. The
channel setup by the LSP may contains the EFS of the network media media channel setup by the LSP may contain the effective FS of the
channel EFS. This is an endpoint property: the egress and ingress network media channel effective FS. This is an endpoint property:
have to constrain the EFS to be the OTSi EFS. the egress and ingress have to constrain the Effective FS to be the
OTSi Effective FS.
4.6. Neighbor Discovery and Link Property Correlation 4.6. Neighbor Discovery and Link Property Correlation
There are potential interworking problems between fixed-grid DWDM and There are potential interworking problems between fixed-grid DWDM and
flexi-grid DWDM nodes. Additionally, even two flexi-grid nodes may flexi-grid DWDM nodes. Additionally, even two flexi-grid nodes may
have different grid properties, leading to link property conflict have different grid properties, leading to link property conflict
with resulting limited interworking. with resulting limited interworking.
Devices or applications that make use of the flexi-grid might 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, different able to support every possible slot width. In other words, different
applications may be defined where each supports a different grid applications may be defined where each supports a different grid
granularity. Consider a node with an application where the nominal granularity. In this case the link between two optical nodes with
central frequency granularity is 12.5 GHz and where slot widths are different grid granularities must be configured to align with the
multiples of 25 GHz. In this case the link between two optical nodes larger of both granularities. Furthermore, different nodes may have
with different grid granularities must be configured to align with different slot-width tuning ranges.
the larger of both granularities. Furthermore, different nodes may
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 need to be negotiated: properties need to be negotiated:
o Grid capability (channel spacing) - Between fixed-grid and flexi- o Grid capability (channel spacing) - Between fixed-grid and flexi-
grid nodes. grid nodes.
o Grid granularity - Between two flexi-grid nodes. o Grid granularity - Between two flexi-grid nodes.
o Slot width tuning range - Between two flexi-grid nodes. o Slot width tuning range - Between two flexi-grid nodes.
skipping to change at page 30, line 17 skipping to change at page 30, line 17
5.1.1. Signaling 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 signaling procedure SHALL allow a 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 (the wavelength range 1530 nm to 1565 nm, which
corresponds to the amplification range of erbium doped fiber
amplifiers) with a slot width granularity of 12.5GHz.
The signaling procedure SHALL be able to configure the minimum width The signaling procedure SHALL be able to configure the minimum width
(m) of a flexi-grid LSP. In addition, the signaling procedure SHALL (m) of a flexi-grid LSP. In addition, the signaling procedure SHALL
be able to configure local frequency 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. (the wavelength range 1565 nm to 1625 nm) and S-band (the wavelength
range 1460 nm to 1530 nm).
The signalling process SHALL be able to collect the local frequency The signalling process SHALL be able to collect the local frequency
slot assigned at each link along the path. slot assigned at each link along the path.
The signaling procedures SHALL support all of the RSA architectural The signaling procedures SHALL support all of the RSA architectural
models (R&SA, R+SA, and R+DSA) within a single set of protocol models (R&SA, R+SA, and R+DSA) within a single set of protocol
objects although some objects may only be applicable within one of objects although some objects may only be applicable within one of
the models. the models.
5.1.2. Routing 5.1.2. Routing
skipping to change at page 32, line 9 skipping to change at page 32, line 9
media channels to be added to or removed from the whole. media channels to be added to or removed from the whole.
The routing protocols MUST provide sufficient information for the The routing protocols MUST provide sufficient information for the
computation of paths and slots for composite media channels using any computation of paths and slots for composite media channels using any
of the three RSA architectural models (R&SA, R+SA, and R+DSA). of the three RSA architectural models (R&SA, R+SA, and R+DSA).
5.5. Support for Neighbor Discovery and Link Property Correlation 5.5. Support for Neighbor Discovery and Link Property Correlation
The control plane MAY include support for neighbor discovery such The control plane MAY include support for neighbor discovery such
that an flexi-grid network can be constructed in a "plug-and-play" that an flexi-grid network can be constructed in a "plug-and-play"
manner. manner. Note, however, that in common operational practice
validation processes are used rather than automatic discovery.
The control plane SHOULD allow the nodes at opposite ends of a link 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 to correlate the properties that they will apply to the link. Such
correlation SHOULD include at least the identities of the node and correlation SHOULD include at least the identities of the node and
the identities they apply to the link. Other properties such as the the identities they apply to the link. Other properties such as the
link characteristics described for the routing information model in link characteristics described for the routing information model in
Figure 17 SHOULD also be correlated. Figure 17 SHOULD also be correlated.
Such neighbor discovery and link property correlation, if provided, 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 MUST be able to operate in both an out-of-band and an out-of-fiber
skipping to change at page 37, line 48 skipping to change at page 37, line 48
[G.872] International Telecomunications Union, "ITU-T [G.872] International Telecomunications Union, "ITU-T
Recommendation G.872, Architecture of optical transport Recommendation G.872, Architecture of optical transport
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", 2013. layer interfaces", 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,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC4202] Kompella, K. and Y. Rekhter, "Routing Extensions in [RFC3945] Mannie, E., Ed., "Generalized Multi-Protocol Label
Support of Generalized Multi-Protocol Label Switching Switching (GMPLS) Architecture", RFC 3945,
(GMPLS)", RFC 4202, October 2005. DOI 10.17487/RFC3945, October 2004,
<http://www.rfc-editor.org/info/rfc3945>.
[RFC4202] Kompella, K., Ed. and Y. Rekhter, Ed., "Routing Extensions
in Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4202, DOI 10.17487/RFC4202, October 2005,
<http://www.rfc-editor.org/info/rfc4202>.
[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,
DOI 10.17487/RFC4206, October 2005,
<http://www.rfc-editor.org/info/rfc4206>.
[RFC5511] Farrel, A., "Routing Backus-Naur Form (RBNF): A Syntax [RFC5511] Farrel, A., "Routing Backus-Naur Form (RBNF): A Syntax
Used to Form Encoding Rules in Various Routing Protocol Used to Form Encoding Rules in Various Routing Protocol
Specifications", RFC 5511, April 2009. Specifications", RFC 5511, DOI 10.17487/RFC5511, April
2009, <http://www.rfc-editor.org/info/rfc5511>.
12.2. Informative References 12.2. Informative References
[RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching [RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label
(GMPLS) Signaling Resource ReserVation Protocol-Traffic Switching (GMPLS) Signaling Resource ReserVation Protocol-
Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
DOI 10.17487/RFC3473, January 2003,
<http://www.rfc-editor.org/info/rfc3473>.
[RFC4204] Lang, J., "Link Management Protocol (LMP)", RFC 4204, [RFC4204] Lang, J., Ed., "Link Management Protocol (LMP)", RFC 4204,
October 2005. DOI 10.17487/RFC4204, October 2005,
<http://www.rfc-editor.org/info/rfc4204>.
[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, DOI 10.17487/RFC4397, February
2006, <http://www.rfc-editor.org/info/rfc4397>.
[RFC4606] Mannie, E. and D. Papadimitriou, "Generalized Multi- [RFC4606] Mannie, E. and D. Papadimitriou, "Generalized Multi-
Protocol Label Switching (GMPLS) Extensions for Protocol Label Switching (GMPLS) Extensions for
Synchronous Optical Network (SONET) and Synchronous Synchronous Optical Network (SONET) and Synchronous
Digital Hierarchy (SDH) Control", RFC 4606, August 2006. Digital Hierarchy (SDH) Control", RFC 4606,
DOI 10.17487/RFC4606, August 2006,
<http://www.rfc-editor.org/info/rfc4606>.
[RFC4783] Berger, L., "GMPLS - Communication of Alarm Information", [RFC4783] Berger, L., Ed., "GMPLS - Communication of Alarm
RFC 4783, December 2006. Information", RFC 4783, DOI 10.17487/RFC4783, December
2006, <http://www.rfc-editor.org/info/rfc4783>.
[RFC4802] Nadeau, T. and A. Farrel, "Generalized Multiprotocol Label [RFC4802] Nadeau, T., Ed., Farrel, A., and , "Generalized
Switching (GMPLS) Traffic Engineering Management Multiprotocol Label Switching (GMPLS) Traffic Engineering
Information Base", RFC 4802, February 2007. Management Information Base", RFC 4802,
DOI 10.17487/RFC4802, February 2007,
<http://www.rfc-editor.org/info/rfc4802>.
[RFC4803] Nadeau, T. and A. Farrel, "Generalized Multiprotocol Label [RFC4803] Nadeau, T., Ed. and A. Farrel, Ed., "Generalized
Switching (GMPLS) Label Switching Router (LSR) Management Multiprotocol Label Switching (GMPLS) Label Switching
Information Base", RFC 4803, February 2007. Router (LSR) Management Information Base", RFC 4803,
DOI 10.17487/RFC4803, February 2007,
<http://www.rfc-editor.org/info/rfc4803>.
[RFC5920] Fang, L., "Security Framework for MPLS and GMPLS [RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, July 2010. Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010,
<http://www.rfc-editor.org/info/rfc5920>.
[RFC6163] Lee, Y., Bernstein, G., and W. Imajuku, "Framework for [RFC6163] Lee, Y., Ed., Bernstein, G., Ed., and W. Imajuku,
GMPLS and Path Computation Element (PCE) Control of "Framework for GMPLS and Path Computation Element (PCE)
Wavelength Switched Optical Networks (WSONs)", RFC 6163, Control of Wavelength Switched Optical Networks (WSONs)",
April 2011. RFC 6163, DOI 10.17487/RFC6163, April 2011,
<http://www.rfc-editor.org/info/rfc6163>.
[RFC6344] Bernstein, G., Caviglia, D., Rabbat, R., and H. van [RFC6344] Bernstein, G., Ed., Caviglia, D., Rabbat, R., and H. van
Helvoort, "Operating Virtual Concatenation (VCAT) and the Helvoort, "Operating Virtual Concatenation (VCAT) and the
Link Capacity Adjustment Scheme (LCAS) with Generalized Link Capacity Adjustment Scheme (LCAS) with Generalized
Multi-Protocol Label Switching (GMPLS)", RFC 6344, August Multi-Protocol Label Switching (GMPLS)", RFC 6344,
2011. DOI 10.17487/RFC6344, August 2011,
<http://www.rfc-editor.org/info/rfc6344>.
[RFC7139] Zhang, F., Zhang, G., Belotti, S., Ceccarelli, D., and K. [RFC7139] Zhang, F., Ed., Zhang, G., Belotti, S., Ceccarelli, D.,
Pithewan, "GMPLS Signaling Extensions for Control of and K. Pithewan, "GMPLS Signaling Extensions for Control
Evolving G.709 Optical Transport Networks", RFC 7139, of Evolving G.709 Optical Transport Networks", RFC 7139,
March 2014. DOI 10.17487/RFC7139, March 2014,
<http://www.rfc-editor.org/info/rfc7139>.
[RFC7260] Takacs, A., Fedyk, D., and J. He, "GMPLS RSVP-TE [RFC7260] Takacs, A., Fedyk, D., and J. He, "GMPLS RSVP-TE
Extensions for Operations, Administration, and Maintenance Extensions for Operations, Administration, and Maintenance
(OAM) Configuration", RFC 7260, June 2014. (OAM) Configuration", RFC 7260, DOI 10.17487/RFC7260, June
2014, <http://www.rfc-editor.org/info/rfc7260>.
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
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