network control in optically switched networksopti500.cian-erc.org/opti500/pdf/lecture 26...
TRANSCRIPT
Overview
• Physical Impairment Aware Routing and Wavelength Assignment in Optically Switched Networks
• Intelligent Aggregation Network Control and Management System for CIAN
12/5/2011 2
Outline • Introduction • Impairment aware routing and wavelength
assignment (RWA) – Impact of physical impairments – Optimal RWA with the quality of transmission
(QoT) constraint – Heuristic RWA with the QoT constraint
• Adaptive QoT-aware routing algorithm • QoT-Friendly wavelength assignment
– Analytical performance analysis
3 12/5/2011
Motivation • The dramatic increase in throughput demands from backbone
transport systems has propelled the development of all-optical networks.
12/5/2011 4
http://lw.pennnet.com/display_article/365016/13/ARTCL/none/none/1/Trans-Atlantic-bandwidth-faces-a-capacity-shortage/?cmpid=EnlDirectJune222009
Introduction
5 12/5/2011
opaque hybrid all optical
Past Present Future
• Evolution of optical networks
OEO router WDM fiber link Optical switch
Introduction • From OEO to optical switching
– Low complexity and energy consumption – Low deployment, maintenance, and operation cost – Transparency – Bandwidth and QoS – On demand service provisioning
12/5/2011 7
DiCon's MEMS 16x16 Matrix Optical Switch
Cisco 12000 Series Router
Challenges
• Optically switched networks – New architecture, technology – Device modeling, placement – Physical impairment accumulation
• Physical impairment aware routing and wavelength assignment
– ...
12/5/2011 8
Careful design of cross-layer network control can efficiently improve the network performance in optically switched networks.
Physical impairments
• Physical impairments in optical networks – Crosstalk
• Linear and nonlinear – ASE noise from EDFA – Shot noise – Thermal noise
12/5/2011 9
traffic independent assuming perfect power compensation
traffic dependent
Impact of physical impairments
• Quality of transmission (QoT) – BER, delay, etc.
12/5/2011 10
20,
220
2221,
2221
01
01 where,22
1
shth
NLXTshthASE
QQerfcBER
σσσ
σσσσσσ
σσµµ
+=
++++=
+−
=
=
( )
( )
( ) e
J
jo
jspsh
e
J
jo
jspXTosh
ethth
J
je
jspoASE
BhfBGnq
BhfBGnPPq
BhfBGnP
−=
−++=
=−=
∑
∑
∑
=
=
=
1
20,
1
21,
22
1
22
12
12
,14
ρσ
ρσ
ησρσ
Derived from the book: G. Agrawal, Fiber-Optic Communication Systems, 3rd ed. Wiley, New York, NY, USA., 2002.
XToXT PP22 ρσ =
Crosstalk
• Linear – Switching – Self – Neighbor
• Nonlinear – FWM – XPM
12/5/2011 12
( )( )
( ) ( )
( ) ( )( )
( ) ( ) ( )( ) (3))(
(2))(
(1)
)()(
1 11,,1,,,,
1,,1,,
1,
0
oadj
S
kxx
S
lyy
ilxmilxmiyxmngbr
oadjilkmilkmself
S
kuu
oswiumsw
n
mngbrselfswXT
PXIIImP
PXIImP
PXImP
mPmPmPP
m m
m
′+′′=
′+′=
=
++=
∑∑
∑
∑
≠=
≠=
+−
+−
≠=
=
λλλ
λλ
λ
( )
( ) ( )∑
∑=
==
m
nlNL
n
mNLNL
lkj
lkjim
im
on usein are ,,
220
22
,,,
,
λλλ
σσ
σσTriple (j,k,l)* . . .
.
.
.
( )lkjnl ,,2σ
* Y. Pointurier, et. al. "Fair QoS-aware adaptive routing and wavelength assignment in all-optical networks," in IEEE ICC, Istanbul, Turkey, Jun. 2006.
Impairment aware RWA
• Lightpath establishment – Wavelength continuity constraint – QoT constraint
12/5/2011 13
LP1
LP2
LP3
http://www.internet2.edu/network/
Optimal RWA for SLE
• With QoT constraint* – Wavelength
• Non-identical
12/5/2011 14
( ) ( )
( )
( ) ( ) ( ) th
zth
Zz Ap
zip
zz
ipi
zi Ap
zip
ii
ii
zipzipzipQ
iApZzTzipQoT
iVjpjI
iApZz
Zz
z
z
τσσµµ
δ
δ
δ
≥+−
=⇒
∀∈∀∈∀≤
∀∈∀≤∈
∀∈∀∈∀≥Λ
∈∀Φ=
=Λ−=Λ
∑∑
∑∑
∈ ∈
∈
,,,,,,
)4(,, ,,,
)3(, ,1)(
)2(,, ,
)1( ,subject to
1minarg1maxargmin
11
21
,
,
,
( )
pjpjIZz
ZzAZ
Zzipi
z
zip
i
path oflink a is if 1)(for sconnection ofnumber :
for paths routing ofset : pair d-s ofset :
for selected are , if 1
onceleast at used is if 1
z
,
=∈∈Φ
∈
∈=
=Λ
δ
bad QoT
* J. He, et. al. "Optimal RWA for Static Traffic in Transmission-Impaired Wavelength-Routed Networks," IEEE Communications Letters, Vol. 12, pp: 694-695, Sept. 2008.
Practical RWA • Practical routing algorithm
– Shortest path algorithm (SP) • Efficient • Distributed • Easy to implement
• Practical wavelength assignment (WA) algorithm – First Fit (FF)
• Pick the first wavelength with lowest index • Low chance of wavelength shortage • High crosstalk level
– Random Pick (RP) • Randomly choose one of free wavelengths • High chance of wavelength shortage • Low crosstalk level
12/5/2011 15
FF WA
RP WA
Numerical results
12/5/2011 16
Opt-RWA: optimal routing and wavelength assignment (RWA)
Opt-WA: optimal wavelength assignment (WA) + shortest path routing SP-FF: not optimal
Gaps (red): performance degradation because of physical impairments
Gaps (Purple): performance improvement because of optimization
Dynamic RWA with QoT constraint • QoT aware and QoT guaranteed • Adaptive
12/5/2011 17
A request arrives
Choose a new wavelength based on wavelength assignment algorithm, such as FF or RP
Find a best available path with a chosen hop weight function for the chosen wavelength
Accept the request
Reject the request
QoT estimation for the chosen lightpath and other involved lightpaths
QoT < threshold
? Yes
Not found
Weight functions in adaptive routing • Shortest distance (SD)
– Length of link i • Fewest hop (FH)
– Constant • Q-maximizing (QM)*
– Average Q factor for existing LPs • Least variance (LV)**
– Based on noises' variance at hop i
12/5/2011 18
{ }{ }otherwise ,max
blocking QoT if ,min),(),(),(),(
max
min
222
αααααααα
ασσσ
∆+⇐∆−⇐
+++=
ii
ii
iASENLXT jijijijiW
* T. Deng, et. al. "Adaptive QoS routing in dynamic wavelength-routed optical networks," in IEEE Broadnets, Oct. 3-7, 2005. ** J. He, et. al. "QoT-aware routing in impairments-constraint optical networks," in IEEE GLOBECOM, Washington, DC, USA, 2007.
QoT-Friendly wavelength assignment
• An important observation
12/5/2011 20
The crosstalk power level is wavelength dependent, with crosstalk from immediately adjacent wavelengths more powerful than crosstalk from those separated by one or more wavelengths.
Conventional first fit WA
QoT-Friendly WA Wavelength ordering RP WA
Wavelength ordering • Optimal ordering • Heuristic ordering
– Static ordering (FFwO)* • Pre-ordering: pick the next one furthest away from the ordered wavelengths • Complexity: O(nm)
– Dynamic ordering (FFwSS)** • Pick a wavelength suffered the least degradations • Complexity: O(nmW2)
– Adaptive wavelength ordering (AFFwSS)** • FFwO or FFwSS based on current network state • Complexity: O(nmW2)
12/5/2011 21
Un-ordered channel lists Pre-ordered channel lists
|)|(),( jiXT ejiP −−= α
* J. He, et. al. "QoS-Aware Wavelength Assignment with BER and Latency Constraints for All-Optical Networks," IEEE/OSA Journal of Lightwave Technology, Vol. 27, pp: 462-474, March 2009. ** J. He, et. al. "Adaptive wavelength assignment using wavelength spectrum separation for distributed optical networks," in IEEE ICC, Glasgow, UK, June 2007.
Simulation results
12/5/2011 22
FF vs RP without impairments
FF vs RP with impairments
FF vs FFwO with impairments
Intelligent Aggregation Network Control and Management System for CIAN
• CIAN projects develop or will develop control module for their components, devices, or test beds. These modules serve as drivers and define the functions and behaviors of the delivered components or sub-systems.
Thrust 2:SubsystemIntegration& SiliconNanophotonics
Thrust 1:OpticalCommunicationSystems& Networking
Rese
arch
Proj
ects
Working Group II:Intelligent Access
AggregationNetworks
Use Cases:Telepresence, 3D holographic
Video
Working Group I:Scalable
& Energy EfficientData Centers
Thrust 3:Materials& Devices
Rese
arch
Proj
ects
Rese
arch
Proj
ects
Packaging & TestUA
Optical Aggregation Testbed (TOAN)
UA
Data CenterTestbed (SEED)
UCSD
Use Cases:Efficient Data centersYou Tube, Facebook
Chip scale Testing
UA and UCSD
DataIntrospection
USC
Cross-layerOptimization
Columbia
Network IntegrationUCSD
Optical Device Characterization
UA
Financial Enterprise
….. Broadband & Triple Play
Wireless Backhaul
Business Services
WDM
MSPP
Ethernet-Switched Packet Network
SONET/SDH, OTN Transport Network
PacketONP
PacketONP
PacketONP
PacketONP
MSPP
PacketONP
PacketONP
PacketONP
PacketONP
…..
TOAN Regime Core Transport Customer Premises
Aggregation Platform: Packet & TDM Svcs. + Optical transport
CIAN Cross-Layer Box Ethernet SONET WDM
Metro Aggregation Regional & Long Haul
Research Challenges
• How to glue heterogeneous components and sub-systems
• How to add the intelligence to the CIAN network
Current Architecture
• A centralized management and control protocol above TCP/IP in application layer – An initiating entity (CMS
software) opens a Transmission Control Protocol connection to the receiving entity (FW nodes or OPM devices) before it sends/receives info with the receiving entity.
– The parties then maintain that TCP connection for as long as the network elements are in use.