optical packet switching the technology and its potential role in future communication networks
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Optical Packet Switching the technology and its potential role in future communication networks. Results from IST project . Lars Dittmann COM – Technical University of Denmark [email protected]. What is the next generation photonic network? (different targets different timescales). - PowerPoint PPT PresentationTRANSCRIPT
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Optical Packet Switching the technology and its potential role in
future communication networks
Results from IST project .Lars Dittmann
COM – Technical University of [email protected]
[email protected] Zagreb 210503
What is the next generation photonic network?
(different targets different timescales)
• Extension to current SDH/SONET network with LCAS, ASON, GMPLS, GFP, etc. ?
• Bitrate and protocol transparent optical datapath with electrical control and management ?
• All-optical network with optical control, information processing and routing ?
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Why do we need the next generation optical network ?
• for cost reduction reasons (cost reduction potential seems larger for optics than for electronics)
• to increase network efficiency and utilisation• for resource savings preserving network reliability and availability• for better network control for fast and efficient configuration of
connections (reduction of manual interventions)• to increase network flexibility and responsiveness to dynamic
traffic demands/changes• because an optical network is in line with a simplified core
structure with more complex and intelligent flow handling at the edges (which was the original idea of the MPLS concept)
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Technological challengespossible optical connection types
Network Resources
Virtual ConnectionOriented
Connection-Less
BurstSwitching
PacketSwitching
Packet and Burst Switching
Virtual Leased Lines& VPNs
ConnectionOriented
Circuit Switching
Leased Lines
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Technological challengespackets vs. circuits
Circuit
Flow
100ns
1ms
10ms
100ms
1ms
10ms
100ms
1s
100 1k 10k 0.1M 1M 10M 0.1G 1G
40 Gbps
Bitrate 2.
5 Gbps Burst
Packet
Tran
sfer
Tim
e
Transaction Size (Bytes)
10s
10 Gbps
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Why packet switching
• Primarily a traffic engineering tool!• Seen as the final goal for network
flexibility, however must be justified • Packet based operation at application level
and transport level should not be mixed up!• Potential new methods for network
resilience in packet based networks (path set-up without resource reservation)
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Optical Burst and label Switchingpotential step towards optical transport plane
Switch controlAdd/Drop control
Control plane interface
lcl1
ln
Out Fibrel0, l1,..., ln
WDM
Mux
1
lcl1
ln
In Fibrel0, l1,..., ln
WDM
Dem
ux 1
Burst Assembly/DisassemblyBuffering
Drop Ports Add Ports
IP Router
Switch Control(Label Swap)
O
E O
E
Labels in Labels out
O/E Conversion
Optical Domain
Electrical Domain
Data interfaces
OpticalSpace
Add/Drop Switch
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• DAVID = Data and Voice Integration over DWDM• A European research project
– Financially supported by the EU commission– IST program
• Goals– Develop concepts and technologies for future, optical networks– Traffic engineering in packet-over-WDM based networks– Control systems for optical networks
• Timeline– Start July 2000, end October 2003
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DAVID Project partners
• Companies– Alcatel, CIT (F)– Alcatel, SEL (D)
• Network operators– BT (UK)– TELENOR (N)– TELEFONICA (E)
• Research centers– IMEC (B)– COM (DK)
• Universities– NTUA (G)– University of Bologna (I)– Politechnica de Torino (I)– LRI (F)– INT (F)– University of Essex (UK)– UPC (E)
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Overall architecture• Key components
– OPADM – optical packet add / drop multiplexer– Hub– Gateway– OPR – optical packet router
• Coverage– MAN and WAN
• Control– MPLS-based
MAN
WAN
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Hierarchical MPLS concept• An MPLS based architecture for mixed-technology
networks• Traffic optimized/conditioned between levels• Levels of various granularity
Level Bandwidth granularity
Electrical MPLS Packets Optical MPLS Larger packets Wavelength routed
Wavelengths
+ wavelength bands, fibers
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The optical packet MAN• Topology - interconnected physical DWDM rings• Each physical ring -> several logical rings• Ring nodes – OPADMs - provide
– Ring connectivity– Legacy network interfaces
• Inter ring traffic controlled by a hub
Opticalswitch
RN1
RN 5MAC protocolMulti-ringsDwdmWavelength bandsOptical packetsOPADM &
legacy interfaces
Management of the flows
Wide Area Network
IP, Ethernet, ...
IP, Ethernet, ...
IP, Ethernet, ...
Legacy interface
Band demuxBand mux
Optical packet Add/Drop multiplexer (OPADM)
Hub
OPADM OPADM
data slot data slotdata slot
data slot data slotdata slot
data slot data slotdata slot
λ0
λ1
λν
...
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– permutations to use are based on measurements of "demand"
– each timeunit Hub switches traffic between rings– permutations to switch multislots between (logical) rings
The metro part: MAN• Hub functionality:
ring 1
ring 2
ring 3
ring 4
ring 1
ring 2
ring 3
ring 4
?ring 1ring 2ring 3ring 4
ring 1ring 2ring 3ring 4
1 2 3 1 3 32 3 4 3 2 13 4 1 2 1 24 1 2 4 4 4
...
...
...
...
ring permutation
slotin
put r
ing
?
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Packet formats
For synchronisation reasons fixed size packets (at transport level) is preferable for small units (nano-micro sec).Variable service units handled by sequence of fixed size packets.
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Ring node evolutionary steps (cost vs. flexibility)
DAVID MAN with active OPADMs
DAVID MAN with passive OPADMs
“Now” “Future”
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Administrative challangesASON vs. GMPLS/MPlS
• Apply the dynamic configuration of service layers to the transport layer(s)
• Integrated control of layers in the network• Optimised use of the individual layers• Standard proposals from: IETF, ITU-T, OIF• Protocol centric solutions (IETF) vs.
architectural centric solutions (ITU-T)• Multi-layer resilience concepts
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Administrative challangesIETF : MPLS/MPlS
leve
l 0(M
AN)
leve
l 1(E
MPL
S)le
vel 2
(OM
PLS)
leve
l 3(M
PλS)
edgerouter
WAN
MAN
Technology hierarchy
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When will the next generation of photonic networks become a reality
• Significant effort needed to lower the cost and enable OAM functions of optical components (higher integration and automatic packaging)
• Better understanding of traffic and performance issues in core and metro networks needed to evaluate cost and reliability issues in current proposals.
• Gain consensus on administrative concepts and standard.• Optical networks must become digital – 3R in all elements
as first process
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When will the next generation of photonic networks become a reality
• Dynamic administration of pseudo optical networks (SONET/SDH) in 2-4 years.
• All-optical networks functions in the data plane obtainable in 5-10 years
• All-optical operation in all layers is not realistic with current know technology (and might never be)
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IST DAVID info @ david.com.dtu.dk
Public demo in October in relation to Public demo in October in relation to
PS´2003 (photonics in switching) in ParisPS´2003 (photonics in switching) in Paris
and(NGPN deliverables @ www.ngni-core.net)