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SubmarineTransmission
WherePhysicsbeatsStandards
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TridentCableSystemSubseaOp9calfibrecable
Fourfibre-pairs,3570km
~45amplifiersinpath
10TbpsPerth-Singapore
16–2420-30TbpsPerth-Jakarta
Relies on non-standard optical technology
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Outline
• Standards• Op9calTransmissionStandards(withnoapplica9ons)
• RecentLong-HaulOp9calTransmissionReality(Non-Standards!)
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Astandard-IEEE802.3(Ethernet)
• Originally10Base5• 10Base2–IEEE802.3a(1985)
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Op9calFibreEthernet1993-10BaseF–10Mbps1995–100BaseFX“FastEthernet”1998–1000Base-X“GigabitEthernet”2002–10GBASE-(SR/LR/ER)“10GigE”
MMF SMF
“-ZR”(80km)?Non-standardvendor“-BX”single-fibre?Non-standardvendorLANPHY–10.313Gbps“tradi9onal”framingWANPHY–9.953Gbps,SDHSTM-64framing
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Op9calFibreEthernet1993-10BaseF–10Mbps1995–100BaseFX“FastEthernet”1998–1000Base-X“GigabitEthernet”
MMF SMF
2002–10GBASE-(SR/LR/ER)“10GigE”
1000xspeedin9years
8 years later…. 2010 – 40G/100GBase.XXX Ethernet
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(SoManyStandardstochoosefrom…)
40GbE/100GbE
8 Considerations for scale NGN Access Networks
Multiple Parallel 10Gb channels
MMOF requires multiple fibres
No long-range 40G - datacentres and
server connect only
100GbE not compatible with
DWDM
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Whymul9plelanes?
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Moore’s Law Transistor count doubles
every 24 months
103.3 104.8
Bandwidth Requirement outstrips Moore’s Law by over 30 times!
Electronics scaling slowly
Nielson’s Law Link Capacity doubles
every 18 months
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Whymul9plelanes?
Bitrate Bits/metre Bit time 10Gbps 54.8 91 ps/18.2 mm 40Gbps 220 22.7 ps/4.5mm
Speed of Light (in glass)?
Desktop CPUs: ~2-3GHz limit per core then 2/4/8 cores On/Off Lasers: ~10GHz-25GHz per lane then multi lanes
10Gbps is FAST! Only 20 cm per nanosecond 0.2 mm per picosecond
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NewMul9modeCabling&Connectors
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400GEthernet
8 years later…. ~2017/8 – IEEE802.3bs 200GE & 400GE MMF–32fibres(16ineachdirec9on)–anothernewMPOconnector/cable
SMFwithindatacentre–8fibres,newPAM4signalformat
SMF“longhaul”–only10kmmax.Formatsincompa9ble–nointerconnectwithaienuators
NO40kmop9on-Incompa9blewithDWDMlong-haul
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StandardsBumpingintoPhysics• 25-50Gbaudpushesboundaryofphysicsandopto-
electronicinterfaces–anymoreincreaseisfromparalleliza9onandmul9plelanes
• PaceofEthernetstandardshasslowed–from1000x/9yrto10x/8yrto2-4x/8yr
• ButNielsen’sLawisnotslowingdown!
• NocapacitybenefittoStructuredCabling–s9llonly10G/fibreMM,100G/fibreSM.MPOconnectorsdifficulttobreakout.
• Addinglatency–every100G+linkrequiresFEC(ForwardErrorCorrec9on)&re-alignmentofparallelsignalsbeforecombining-~20-30microsecondsperlink
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EthernetIrony!
Point-to-PointFullDuplex
Onetransmiier,Onereceiverper“wire”
NoCollisions!
EthernethasevolvedtomakeCSMA/CDsuperfluous!
EveryEthernetsegmentisnow…
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Intercon9nentalCapacity
Non-Standards!
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Long-haulOp9calTransmission• Eachfibrecoreisexpensive–
requiresmanyamplifiers,repeaters,andpower
• Verylowfibre-count–2,4,6pairs.
• Big$$$onterminalequipmenttomaximisethroughputperpairusingDWDMtechniques
• 40–80amplifiersmeanshighaienua9on,lowSNR,closetonoisefloor
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SubmarineChannelCapacity
Capacity per wavelength Year Cable
2.5 Gbps 1995-2000 various
10 Gbps 2000-2010 Japan-US, AJC
40 Gbps 2011 APCN2 upgrade
100 Gbps 2012- SCCS upgrade, FASTER, many
200 Gbps (trial 2014) (Japan-US 630km
segment)
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Mul9pleChannels
• ITU-TG.694.1SpectralGridsforDWDM
• Defined ~80 channels, 50 GHz spacing 80 x 10 Gbps = 800 Gbps per fibre-pair
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LongHaul100G• LinecodingdevelopedbyNortel
–DP-QPSK–adoptedbyOIF(Op9calInterworkingForum)
• Combine2separateparallelsignals
• ~112Gbpsfrom2x25-28Gbaudperseccarriers
• Works through existing 50 GHz DWDM equipment • More robust than 40Gbps NRZ (On-Off-Keying) • shipping equipment from 2010 • Completely different from 100G Ethernet signalling
80 x 100 Gbps = 8 Tbps per fibre-pair
No interoperable standard
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100Gbps–Non-Standard!
• ITU-TG.959.1OTNPhysicalLayerInterfaces(2012)
Class Speed
OTU-1 2.5Gbps
OTU-2 10Gbps
OTU-3 40Gbps
• No100Gbpsphysicalinterfacedefined! No standard (use 100GbE)
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CoherentDetec9on• ~2010dedicatedDSPprocessorsbecamefastenoughto
directlyprocessop9calsignal
• Soswarecorrec9onforChroma9c&Polarisa9onDispersion
• Locked-Laserfrequencyvastlybeiernoiserejec9on&sensi9vity
• Instantlyenabledjumpfrom10Gbpsto100Gbps
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NarrowerChannels
Re-paintthelane-lines–squeezechannelsinto37.5GHzspacing
• 80(+25%)100channelsinthesamespectrumband
100 x 100 Gbps = 10 Tbps per fibre-pair
Non-standard
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Wider‘Superchannels’
Combineadjacentchannelstocarryhigherbit-ratesinlessspectrum
• 400Gbpsin(2x50)100GHzsuperchannel600 GHz 488 GHz 462.5 GHz
Infinera White Paper - https://www.infinera.com/wp-content/uploads/2015/07/Infinera-WP-Evolution_of_Next-Gen_Optical_Networks.pdf#page=9&zoom=auto,-12,499
40 x 400 Gbps = 16 Tbps per fibre-pair
Non- standard!
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MoreChannels• ITU-TG.694.1SpectralGridsforDWDM
• 37.5Ghz channels & superchannels completely non-standard….
• …until Feb 2012 Edition 2 defined ‘Flexible Grid’ on 12.5 GHz granularity.
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200G,300G,400G….• Morecomplexencoding-8QAM,16QAM(followingradiotech)
6240km 2880km 1680km @25Gbaud 100G 150G 200G
@50Gbaud 200G 300G 400G
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BeierFibre
• “Standard”fibres–0.22dB/km,core65μm2
• Low-LossFibre–0.17dB/km
• ~25%longerspans,fewerrepeaters,lowernoise• LargeEffecGveAreafibre–core130μm2
• SupportsHighersignalpower,biggeramplifiers
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Compromises
• Currentlyatlimitofop9cal&electricalphysicsandspeeds
• Tradeoffofratevsreachvsbandwidthvsstability
FurtherintotheFuture….
(Spurringanewwaveofnewcables…)
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Mul9-coreSingle-mode
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NTTlabs
https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr201412ra3.pdf&mode=show_pdf
