Networks and Optical Communications group – NOC
Adding application awareness in
flexible optical networking
Presenter:
Dimitrios Klonidis
Outline
Evolution of optical communication systems & networks
What is flexible optical networking
Application awareness in flexible optical networking
– the ACINO project approach
Upcoming services are huge bandwidth
generating sources:
• Video services
• Data services to/from mobile users
• Cloud services
These new traffic sources lead to new
characteristics:
• Rapidly changing traffic patterns -
high traffic churn
• High peak-to-average traffic ratio
• Large data-chunk transfers
• Asymmetric traffic between nodes
• Increasing high-QoS traffic
• …
Maintaining network resource
over-provisioning is not possible any more
Source: Transmode
Over-provisioning
Over-provisioning
Optical communications system capacity
and bit-rate x distance product
•
A
forward-looking option:
deploy new fibers (or use strands of available SMF fibers) that can support
multi-cores or/and multi-modes per core
(SDM/Spatially-flexible networks)
•
A
short-term solution:
utilize the available fiber spectrum more efficiently
-
(Spectrally flexible
networks)
0.00001 0.0001 0.001 0.01 0.1 1 10 100 1000 0 1 10 100 1,000 10,000 100,000 1,000,000 10,000,0001983 1987 1991 1995 1999 2003 2007 2011 2015
T
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tal
F
ib
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C
ap
aci
ty
(T
b
it/
s)
B
it
R
ate
D
istan
ce
Pr
o
d
u
ct
(Gb
it/
s.
M
m)
Year Published
WDM TDM OFDM/CoWDM Coherent Detection Spatial Multiplexing Total capacity• Traffic increases at a rate of
20-40% per year, while capacity of
deployed SMF-based networks
approaches fundamental limits…
• Fiber bandwidth was consider for
many years as an abundant
resource, but we
have almost
utilized to the maximum extend
the EDFA amplifiers bandwidth
(i.e. while approaching the
fundamental SE limits)
The technology shift to coherent mesh
networks
Multi-level (>2) modulation
formats for improved
spectral efficiency and reach
Coherent detection
Polarisation division
multiplexing/demultiplexing
Digital signal pre/post
processing algorithms
High speed ASICs/FPGAs
Photonic ICs
10G
100G
40G
400G
Multi-rate variable spectrum
interface
10G
43Gb/s @50GHz
112Gb/s @50GHz
224Gb/s @50GHz
448Gb/s @80GHz
1Tb/s @170GHz
Flexible/elastic optical networks
The definition
Flexible (Elastic) Optical Network = A network able to adapt its resources (link capacity,
transmission bandwidth per node, switching capacity etc.) according to the connectivity (i.e.
traffic) demands in an automated fashion
•
Flexible, elastic, tunable, gridless, or adaptive
are few examples of the terms used by the
research community to describe such solutions
The target
•
Offer optimization of the poorly-filled wavelengths of the fixed spectrum grid via a flexible
spectrum allocation that requires a new wavelength-grid enabling adaptive sub-wavelength
and super-wavelength services
400G
40G
10G
100G
400G
40G
Flexible
Spectrum
Spectrum-Flexible Optical
Node
Spectrum-Flexible Optical
Node
Adaptive
Line-Rate/
Modulation Format
f
B a n d w id th -F le x ib le W S S B a n d w id th -F le x ib le W S S B a n d w id th -F le x ib le W S S B a n d w id th -F le x ib le W S SFlexible Optical Networking
Enabling elements to realize flexible
networking
Main building blocks for enabling flexible networks:
Flexible transponders
Network planning &
control plane
Flexible switching
nodes
Min. WSS
resolution
e.g. 12.5GHz
Nyquist WDM
Optical OFDM
or
Elctronic OFDM
(i.e. with SC generated in el. Domain)
Nyquist-FDM
(i.e. with N-shaped spectra generated electronically)
m-QAM
(format selectable)
Multiplexing schemes and modulation
formats to compose super-channels
A flexible node architecture
Expanding the link capacity limits
Time
:
•
Too expensive to go to higher symbol rates (>32Gboud)
•
PMD starts becoming an issue
Format level
:
•
Multi-level schemes have reduced transmission distance and increased processing complexity
Polarization level
:
•
Is limited to two levels
Frequency
:
•
Increased spectrally-efficiency with the use of flexible multiplexing schemes (i.e. Nyquist WDM and
optical OFDM),
BUT
still limited capacity increase (Shannon limit)
•
Expansion to other wavelength bands beyond C+L may be a solution (still limited), but requires wideband
modules
Space
:
•
This is the obvious yet unexplored dimension
•
“if capacity is limited then offer multiple systems in parallel”
… BUT by simply increasing the number of systems, the cost and power
consumption also increase linearly!
15
Hero transmission experiments
… BUT all these are very good for the spatial capacity increase in
Point-to-Point systems…
Capacity expansion … In Space
The true use of the space domain requires the…
…“
spatial integration of system elements
”*
• Significant efforts in the development of
FMF and MCF
(fibre integration)
•
Multi-link amplification systems
have also be proposed and developed
•
Tx/Rx integration
is a hot and very active topic
… BUT,
all these are good only for the spatial capacity increase in Point-to-Point
systems
WHAT ABOUT using the spatial dimension for optical networking?
Modes/Cores
Wavelengths
Data rate
(Modulation level)
Degrees of Flexibility
The INSPACE channel allocation concept
Modes
or
Cores
f
f
f
f
f
: end-to-end allocated channel
“
Spatial expansion of the
spectrum over multiple
modes/cores and therefore
definition of a superchannel
over two dimensions
(instead of the spectrum
only dimension)”
SMF-Bundle
or
FMF
or
MCF
Frequency FrequencyConventional optical OFDM Optical fast OFDM
(N-1)/T
(N-1)/2T
Nis the channel number (=7 in this example)
(a) (b)
Frequency Frequency
Conventional optical OFDM Optical fast OFDM
(N-1)/T
(N-1)/2T
Nis the channel number (=7 in this example)
(a) (b)
N-WDM
or
OFDM
or
SC-M-QAM
Fibre,
Mode
,Core
Routing and resource optimization
Traditional approaches use the wavelength
channel allocation option
•
Requires wavelength
routing algorithms
In flexible networks a number of subcarrier slots
are now to be assigned
•
Routing and
spectrum allocation algorithms
(RSA).
As the modulation level can be selected on a
connection basis, constraints tying it to the
required bit-rate versus the achieved reach, are
necessary.
•
Routing
modulation level
and spectrum allocation
algorithms (RMLSA).
A further addition is the allocation of spatial
super-channels to fiber cores/modes
•
Spatial
routing modulation level and spectrum
allocation algorithms (S-RMLSA)
The discussed algorithms can address the offline
network planning phase, or they can be applied
to
dynamically provision
connection requests.
•
Speed???
Networking and Control
Significant
improvements are
needed in the control
plane architecture that
should provide a new
set of functionalities,
such as:
• Flexible/elastic traffic
support
• Physical layer
awareness
• Multi-domain and
multi-vendor support
• Network
virtualization
• Evolution towards
cognitive networks
Networking and Control
What does the space
dimension bring in
networking:
• More routing and channel
allocation options
more
optimization options
in
terms of:
Link capacity
Cost (Capex-Opex)
Energy efficiency
• Hitless spectral
defragmentation
using the
space domain
• Support of “actual”
network virtualization
with spatial separation
virtual network segments
Capacity flexibility can be
maintained in spectrum
domain
• BUT
increased complexity
in the control plane
Spatial allocation of
VN segments
Control plane options for flexible
networking
•
Fixed rate channel allocation
in wavelength domain
• λ reconfigurability, ROADMs
legacy networks
future flexible networks
Spectrum
dimension
Spectrum + BW flex
dimension
Spectrum + BW + Spatially flex
Ch
an
n
el
al
lo
cati
o
n
o
p
ti
o
n
s
Space
d
im
en
si
o
n
Con
tro
l
p
lan
e
so
lu
ti
o
n
s
•
Static spatial expansion to
multiple links
•
GMPLS based control plane
–
Well defined and worked fine
•
Adaptive rate channel allocation in
wavelength domain
–
Programmable (i.e. adaptive) devices
–
Sliceable spectrum
•
Static spatial expansion to
multiple links
•
GMPLS extensions required
–
to take the BW flexible option into
consideration
•
SDN concept into networking
–
efficient control of programmable
resources in a sliced spectrum
•
Adaptive rate channel allocation in
wavelength AND space domains
–
Extend flexibility (programmability) to
space domain (switching nodes)
•
Adaptive spatial expansion to
multiple links/cores
•
A GMPLS may lead to suboptimal
allocation of multi-dimension
resources (+scalability issues)
•
SDN can make the difference!
–
Support of multi-dimensional flexibility
Why SDN in flexible optical networks?
SDN and GMPLS (the common centralized version) have the same goal
the “efficient” routing of demands in a network.
• They both consider all the network resources available and can potentially optimize their
use
• They both rely on the use of path computation to identify the less costly path
However … what changes are:
a) The capabilities of the modern data plane (i.e. the DSP enabled hardware capabilities)
b) The amount of data required to be optimized (processed)
The key benefits of SDN in flexible optical networking are:
• The
more efficient control and management
of complicated networks
The higher the complexity the more efficient (compared to the limitations of GMPLS)
• The
manipulation of traffic
(packet)
according to type
Extra capabilities when the IP type of traffic comes into play
• The capability to
deal with virtualized network
infrastructures
Application awareness in flexible optical networking
– the ACINO project approach
Dimitrios Klonidis ([email protected]) - AIT
27
I-CAN Workshop, June 2015, Athens, Greece
The view of ACINO project
So far, the optimization of the Flexible optical network resources is
equivalent to the optimization of the data plane resources according
to the end-to-end demands
However, demands are generated from a diverse set of
applications/services with different needs
While the applications can be treated differently by the IP layer
(QoS), they are aggregated and treated commonly before they are
routed in the optical layer
Concept 1: Since
flexible optical networking
can adapt to the end-to-end
demands, why not
to be adaptive to the type of services/applications per
demand
.
SDN allows application control over the use of network resources,
but this is again limited to the IP layer
Concept 2: The need for an
application-centric network orchestration
is
foreseen.
Approach:
From application-unaware baseline…
Application-unaware baseline
• application classes could be treated differently at the IP layer by
its built-in QoS mechanisms
not currently a feature of the optical layer
• All traffic served by an IP interface mapped into an optical
connection sent towards the destination IP interface
At the edge of the transport network traffic for all
applications to the same next IP hop are translated
into an optical wavelength
E
D
SD Application class“red” traffic from S to D SD Application class “green” traffic from S to D SD Application class “blue” traffic from S to D
Legend
IP/Optical Transport Network
N1
N2
N3
B
A
DC
C
B
E
D
At the edge of the transport network
same/equivalent applications data are multiplexed
into smaller optical sub-wavelengths (thanks to
sliceable transponders)
IP/Optical Transport Network
N1
N2
N3
SD Application class“red” traffic from S to D SD Application class “green” traffic from S to D SD Application class “blue” traffic from S to D
Legend
A
DC
C
DC
Approach:
… to application-centricity!
Application-centric networking
• keep the different application classes separate down to the optical
layer
Different service (latency, survivability, security, ...) for apps
• IP/Opt: global vision, joint/differentiated optimization (virtual
IP/Optical networks per class)
Approach:
dynamic controller and primitives
A dynamic IP/Optical orchestrator able to expose to applications
primitives to be mapped into service
N1 N2 N3
Controller logic
D
ynam
ic
R
es
our
ce
A
lloc
ati
on
O
nl
ine
P
lanni
ng
Application-centric algorithmsO
rch
e
str
a
to
r
mo
d
u
le
s
…
….
APIs
p ri m it ive s p ri m it ive s p ri m it ive sApplications / Network Management System
PRIMITIVES SPACE
Routing metrics Bandwidth Latency
….
In-Operation Planning YesEach 30 Minutes Objective: save energy
No
….
….
Specific application class needs
SERVICE
(how network is programmed)
….
Survivability Optical Protection Multi-layer Restoration Chosen PrimitivesFlexible OADM Flexible OADM Flexible OADM Flexible OADM Flexible OADM Flexible OADM
R1
R2
R3
R3-R1 flow (80)R3-R2 flow (20)
R1-R2 flow (60)
Flexible OADM Flexible OADM Flexible OADM
R3-R1 flow (80)
R3-R2 flow (20)
R1-R2 flow (60)
