terascale network technology workshop - solutions for lightpaths - architecture, control and cost
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Terascale Network Technology Workshop - Solutions for Lightpaths - Architecture, Control and Cost. Kim Roberts, & Michel Belanger Optical Systems July 17, 2005. A LightPath. A network connection that provides guaranteed capacity, constant latency, and high reliability. - PowerPoint PPT PresentationTRANSCRIPT
Terascale Network Technology Workshop- Solutions for Lightpaths
- Architecture, Control and Cost
Kim Roberts, & Michel Belanger
Optical Systems
July 17, 2005
2 Nortel Confidential – Information under NDA
A LightPath
> A network connection that provides guaranteed capacity, constant latency, and high reliability.• Provisioned by a control plane. • Megabits to Terabits per second• The optimum implementation can be L0, L1, or L2, depending on
the capacity needed and facilities available
Layer 2 Packet EthernetLayer 1 Transport OC-192Layer 0 Photonic Photons
Layer 2 Packet EthernetLayer 1 Transport OC-192Layer 0 Photonic Photons
3 Nortel Confidential – Information under NDA
Challenges in using Lightpaths
> Layer 0 Photons• Need to make the connection independent of optical physics• Need effective way of switching of lots of wavelengths – any to any
> Layer 1 OC-192• Need to map efficiently into the appropriate bandwidth• Need cost-effective switching of lots of STS-Ns
> Layer 2 Ethernet Connections• Need to aggregate packets while preserving quality• Need cost-effective management of lots of VLANs
4 Nortel Confidential – Information under NDA
Summary: Lightpath Solutions
> Layer 0 Photons• Have made the connection independent of optical physics• WSS effective switch for lots of wavelengths
> Layer 1 OC-192• GFP/VCAT/LCAS maps efficiently into the appropriate bandwidth• OME and HDX effective switching for lots of STS-Ns
> Layer 2 Ethernet Connections• L2SS aggregates packets while preserving quality• L2SS, RPR provides cost-effective management of lots of VLANs• RPR provides high reliability ring.
5 Nortel Confidential – Information under NDA
Making Layer 0 Independent of Optical Physics
> What is wrong with physics?
> Solutions in CMOS
6 Nortel Confidential – Information under NDA
Hurdle: Fiber Dispersion Management
ROADM
SMF-28
SMF-28
SMF-28
E-LEAF
E-LEAF
E-LEAF
TWcTWc
PhotonicCross-Connect
PhotonicCross-Connect
PhotonicCross-Connect
Bulk dispersion compensation will not suffice
7 Nortel Confidential – Information under NDA
Effect of Dispersion
Transmitted Eye Eye after 320 km of Fiber
8 Nortel Confidential – Information under NDA
Optical Nonlinearities
> Self Phase Modulation (SPM) arises from the Kerr effect, where the amplitude of an optical signal changes its phase.• Rapid phase changes interact with chromatic dispersion to distort
high capacity optical signals.
> Cross Phase Modulation (XPM) is the similar effect between channels.
> Other nonlinearities: Four wave mixing, SRS, SBS, MI
> Amplified Spontaneous Emission (ASE) is optical noise
9 Nortel Confidential – Information under NDA
Issues with using present methods
10 Nortel Confidential – Information under NDA
Dispersion Compensation Modules (DCM)
> Coils of 1 to 20 km of special fiber
> 3 to 9 dB of loss
> One module for C, another for L band
> $3k to $10k per module
> Different slopes for different fiber types
> Generally needed at each line amp site• Depending upon fiber type, system topology, span lengths.
All the above still does not get us over the hurdle of full agility or address multiple line rates
11 Nortel Confidential – Information under NDA
Layer 0 Solutions
12 Nortel Confidential – Information under NDA
Transmitter Pre-compensation
Opticalmodulator
laser
D/A
D/A
CD-1
Digitaldata
Recovered data
0
Tx Rx
-30 -20 -10 0 10 20 30
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
13 Nortel Confidential – Information under NDA
Electronic Dispersion Compensation320 km of G.652 fiber, 2.5 dBm launched
No Compensation
14 Nortel Confidential – Information under NDA
Received Eye Diagram320 km of G.652 fiber, 2.5 dBm launched
No Compensation WARP CompensationOvercomes Dispersion
15 Nortel Confidential – Information under NDA
10 Gb/s with no Traditional Dispersion Compensation
Eye diagrams after transmission over standard G.652 fiber with Nortel WARP processing.
0 Km 1600 km 3200 km 5120 km
16 Nortel Confidential – Information under NDA
Forward Error Correction to mitigate noise
0
[dB] CodingGain
4.0
8.0
12.0
WRAP10
WRAPTOR
TRIFEC
FECAug 1996
10.0
6.0
2.0
RS-8; 6.2 dB (G.975)
2000 2001 2002 2003
0.13 um CMOS6M gates
9.2 dB; 7% OH 0.18 um CMOS
2M gates7.4 dB; 7%BCH-20
0.5 um BiCMOS600K gates4.2 dBBCH-3
Shannon Bound @ 7% (~ 10.4 dB)
3 dB
Performance: Effective Coding Gain> Wraptor corrects an error rate of 0.38% to < 10-16
> Increased system gain and improved burst tolerance
Performance: Effective Coding Gain> Wraptor corrects an error rate of 0.38% to < 10-16
> Increased system gain and improved burst tolerance
17 Nortel Confidential – Information under NDA
Simplified Optical Line Enables Lightpaths
OADM NodeM
ux
Terminal Node AMP Node
OEO
OEO
…
Mu
xOEO
OEO
…
DCF
DCF
DCF
DCF
DCF
DCF
DCF
DCF
OEO
OEO
…
OEO
OEO
…DCF
DCF
Dem
ux
Dem
ux
Terminal Node
Ram
an
Ram
an
Ram
an
OEO
OEO
OEO
OEO
OEO
OEO
WSS NodeTerminal Node AMP Node Terminal Node
Tom Di PasqualeOptical Solutions
Paul DaspitAdvanced Technology Research