This document provides a framework for controlling wavelength switched optical networks (WSONs) using GMPLS and path computation element (PCE) protocols. It describes WSON subsystems like wavelength links, ROADMs, and wavelength converters. It discusses how these new network elements impact routing, signaling, and path computation. The document also relates this framework to ITU-T recommendations on optical transport network architectures and seeks to resolve modeling issues when including wavelength conversion functionality.

1. 72th IETF – Dublin, Ireland,Page - 1
Framework for GMPLS and PCE Control of
Wavelength Switched Optical Networks
(WSON)
Greg Bernstein gregb@grotto-networking.com
Grotto Networking
Young Lee ylee@huawei.com
Huawei
Wataru Imajuku imajuku.wataru@lab.ntt.co.jp
NTT
draft-ietf-ccamp-wavelength-switched-00.txt

2. 72th IETF – Dublin, Ireland,Page - 2
Authors/Contributors
• Snigdho Bardalai (Fujitsu)
• Greg Bernstein (Grotto Networking)
• Diego Caviglia (Ericsson)
• Wataru Imajuku (NTT)
• Daniel King (Aria Networks)
• Young Lee (Huawei)
• Dan Li (Huawei)
• Itaru Nishioka (NEC Corp.)
• Lyndon Ong (Ciena)
• Jonathan Sadler (Tellabs)

3. 72th IETF – Dublin, Ireland,Page - 3
WSON Framework
• Describes wavelength switched optical networks
(WSON), subsystems and associated processes.
Emphasizing those aspects that are different from
other technologies that utilize a GMPLS control
plane.
• Optical impairments are not currently considered
in any depth since different approaches to
impairments are used in different types of WSONs.
• Summarize implications to GMPLS routing and
signaling, and to PCE protocols.

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Contents
• WDM systems from control plane point of view
(new path computation constraints)
– WDM links
– Laser Transmitter/Modulator
– ROADMs, FOADMs, and OXCs
– Wavelength Converters
• Discussion of RWA problem
• Discussion of Signaling, Routing and PCE
“centric” approaches
• Implications for GMPLS and PCE
– Signaling, Routing, PCEP, etc…

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Relation to ITU-T Documents
• Based on ITU-T data plane models and documents
– G.872 Architecture of optical transport networks (drafted new
section explaining this and cite)
– G.65x optical fiber specifications (cited)
– G.671 Transmission characteristics of optical components and
subsystems (this rec. includes definitions of OADM, splitter,
combiner, etc… will cite in next revision)
– G.959.1, Optical Transport Network Physical Layer Interfaces,
March 2006 (cited)
– G.694.1,.2 Spectral grids for WDM applications (cited)
– G Supplement 39, Optical system design and engineering
considerations, February 2006. (cited)
– G Supplement 43, Transport of IEEE 10G base-R in optical
transport networks (OTN), November 2006. (cited)

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Next Steps
• Add section relating this work to ITU-T
G.872 architecture
– Work to resolve some modeling issues when
wavelength converters are included.
• Usage Scenarios
• Alignment with emerging drafts such as
info model, encoding and signaling.

7. 72th IETF – Dublin, Ireland,Page - 7
G.872 Optical Transport Network
Architecture (example)
Optical
Amplifier #1
Optical
Amplifier #2
Optical Add/
Drop
multiplexor
Optical
Multiplexor
Optical De-
multiplexor
= Optical Fiber
= Optical Support Channel
for “Transport layer”
= Optical Support Channel
for “multiplex layer”
OCh
OMS
OTS OTS OTS
OCh
OMS
OTS
OCh
OMS
OTS
Optical Channel
Optical Multiplex
Section
Optical Transport
Section

8. 72th IETF – Dublin, Ireland,Page - 8
Including wavelength converters
• ITU-T Models
– G.872 OCh characteristic information (CI): maximum bandwidth
and SNR (Section 5.3).
– Example of OCh through a wavelength converter in Appendix I,
since the wavelength converter doesn’t change the CI this doesn’t
change layers.
– G.709 “… OCh transports a digital client signal between 3R
regeneration points.”
• Framework draft uses “Lightpath”
– We didn’t define the characteristic information for this yet but
signaling drafts are leaning towards such information as
modulation, modulation parameters, bit rate and FEC.
• Most (?) wavelength converters are OEO and are also 3R
regenerators.
– Would like to handle connection through wavelength converters as
a single LSP without stitching RFC5150 if possible for most
common cases.