400G Optical Modules nyob rau niaj hnub Networks

 

Form Factor Wars Tsis muaj leej twg yeej

 

QSFP-DD thiab OSFP tau tshwm sim los ntawm cov txheej txheem txheej txheem zoo li ob tug kwv tij uas tsis tuaj yeem pom zoo rau ib yam dab tsi tshwj tsis yog tias lawv ob leeg xav tau 400G. Kev lag luam xav tau yim txoj kab hluav taws xob ntawm 50Gbps txhua qhov, thiab ob lub koom haum sib txawv tau txiav txim siab los daws qhov teeb meem ntawm ob txoj kev sib txawv.

QSFP-DD yeej qhov kev sib cav sib ceg. Nws haum QSFP28 tawb uas twb muaj lawm yog tias koj squint nyuaj txaus thiab tsis mloog cov kab thib ob ntawm tus pins. Backward compatibility tseem ceeb thaum koj muaj kaum tawm txhiab tus xa tawm cov chaw nres nkoj thiab CFO uas nug cov lus nug txog cov khoom muaj nqis.

OSFP yeej qhov kev sib cav thermal. Lub vaj tsev loj me me thiab kev sib xyaw ua ke heatsink txhais tau tias koj tuaj yeem ua rau 15-20 watts cov modules kos yam tsis muaj qhov chaw nres nkoj nyob ib sab. Kuv tau pom cov kab ntawv nyob qhov twg lub ces kaum QSFP-DD cov chaw nres nkoj tsis tu ncua khiav 8℃kub dua li nruab nrab vim tias cov qauv airflow xav tias 100G lub hnab ntawv lub zog.

Tsis yeej yeej. Feem ntau cov hyperscalers tau mus QSFP-DD rau cov lus nug yooj yim. Feem ntau ntawm kev xa xov tooj mus rau OSFP vim tias lawv cov qauv sib txuas xav tau lub hauv paus thermal. Txhua tus neeg tau xaiv txhua yam uas lawv tus neeg muag khoom xa khoom xa tuaj thiab tsiv mus.

QSFP112 variant tsim nyog tau hais vim nws ua rau txhua tus neeg tsis meej pem. Plaub txoj kab ntawm 100G txhua- tib 400G sib sau ua ke, tsawg dua txoj kab, SerDes tshiab. Nws tseem ceeb rau NIC kev sib txuas qhov twg koj xav tau server-rau-TOR txuas yam tsis muaj DSP gearbox nyuaj. Nws tseem ceeb tsawg dua li cov neeg muag khoom thov nyob rau lwm qhov.

 

PAM4 Hloov Txhua Yam (Thiab Tawg Qee Yam)

 

Nov yog qhov tsis muaj leej twg piav qhia tau zoo thaum lawv muag koj ntawm 400G: PAM4 signaling lag luam suab nrov tiv thaiv kev ua haujlwm bandwidth, thiab qhov kev lag luam tawm tsis pub dawb.

NRZ encoding siv ob theem teeb liab. Siab lossis qis. Ib los yog xoom. Koj tus neeg txais khoom tsuas yog xav tau kom paub qhov txawv ntawm ob lub xeev, thiab daim duab qhov muag tau muab cov npoo zoo rau koj. PAM4 siv plaub theem-00, 01, 10, 11- uas txhais tau hais tias koj tus neeg txais tam sim no yuav tsum paub qhov txawv ntawm peb qhov kev hla hla nrog ib feem peb ntawm qhov sib cais voltage. Qhov theoretical 9.54dB SNR nplua tsis yog qhov theoretical kiag li. Nws tshwm sim hauv koj qhov pre-FEC BER cov txee txhua hnub.

Lub DSP hauv 400G module ua haujlwm ua haujlwm zoo rau qhov no. Pub-rau pem hauv ntej sib npaug, kev txiav txim siab sib npaug, moos thiab cov ntaub ntawv rov qab-tag nrho khiav ntawm 53.125 GBaud ib txoj kab. Thaum nws ua haujlwm, nws tsis pom. Thaum nws tsis ua haujlwm, koj tau tawg ntawm qhov raug kho tau raug txiav los ntawm qee lub sijhawm tsis raug kho, thiab hmoov zoo nrhiav seb qhov teeb meem yog koj qhov module, koj lub fiber, koj tus tswv tsev, lossis lub cosmic keeb kwm yav dhau tawg.

 

 

Wavelength Variants: Ntau tshaj li ncav cuag

 

Cov ntsiab lus ncav cuag tsuas yog ib feem ntawm zaj dab neeg xwb.

400G-SR8 siv 850nm VCSELs hla yim kab sib npaug, tsom 100 meters tshaj OM4. Nws yog pheej yig. Nws yog multimode. Nws yuav tsum muaj MPO-16 txuas nrog yim TX thiab yim RX fibers. Hauv ib lub racks lossis nruab nrab ntawm cov racks uas nyob ib sab, qhov no ua haujlwm zoo. Lub sijhawm ib tus neeg nug txog kev khiav nws "tsuas yog ntxiv me ntsis," ceeb toom lawv tias modal dispersion ntawm 850nm tsis sib tham.

400G-DR4 ua haujlwm ntawm 1310nm tshaj plaub qhov sib npaug ib zaug - hom fibers, ntsuas rau 500 meters. Lub MPO-12 connector siv lub yim fibers sab nraud thiab tawm plaub yam tsis siv-qhov tseeb uas ua rau cov cable installers tsis meej pem ib zaug rau kev xa tawm. DR4 tau dhau los ua tus neeg ua haujlwm rau nplooj ntoo- qaum kev sib txuas hauv cov nroj tsuag ib hom vim tias 500 meters npog feem ntau datacenter geometries nrog rau chav nyob.

400G-FR4 siv CWDM4 wavelengths (1271, 1291, 1311, 1331nm) multiplexed mus rau ib leeg fiber ntau ntawm duplex LC. Ob kilometers ncav cuag. Qhov no yog qhov uas 400G pib xav tias kev lag luam hauv tsev kawm ntawv sib cuam tshuam, vim tias koj tsis rub yim- fiber ntau MPO trunks ntawm lub tsev.

400G-LR4 stretches tib lub CWDM4 mus kom ze rau 10 kilometers nrog lub zog tso tawm ntau dua thiab cov txais tau zoo dua. Tus nqi dhia los ntawm FR4 mus rau LR4 tseem ua rau cov chaw muag khoom xav tsis thoob uas tsis tau hloov kho lawv cov qauv kev xav ntawm 100G-LR4 tus nqi.

 

Lub Coherent Elephant

 

400G-ZR tsim nyog nws cov seem vim nws sawv cev rau ib qho kev sib txawv ntawm cov thev naus laus zis hnav hauv tib daim ntawv.

Txhua yam kuv tau piav txog tam sim no siv ncaj qha - kuaj pom optics. Lub teeb nkag mus, photodiode hloov nws, DSP ntxuav nws. Coherent optics encode cov ntaub ntawv nyob rau hauv ob qho tib si amplitude thiab theem thoob plaws ob polarizations ib txhij, ces siv lub zos oscillator thiab sophisticated digital teeb liab ua kom rov qab tau txhua yam ntawm lub receiver. Qhov tshwm sim: 400Gbps tshaj 120+ kilometers ntawm unamplified fiber nyob rau hauv ib tug pluggable module.

Tus qauv OIF 400ZR qhia txog 16QAM kev hloov kho ntawm 60 GBaud nrog dual polarization. FEC concatenated (soft-kev txiav txim siab sab hauv Hamming, nyuaj- kev txiav txim siab sab nrauv staircase) muab txog 10.8dB ntawm net coding nce. Tag nrho cov khoom rub tawm 15-20 watts thiab tsim hluav taws xob uas yuav ua rau QSFP-DD module quaj.

Kuv tau pom ZR modules tau teeb tsa hauv cov keyboards uas tsis tau tsim los rau qhov thermal load. Lub chassis hloov pauv tau tshaj tawm qhov kub thiab txias vim tias nws cov khoom siv nkag tau ntsuas cua txias. Lub module tau tshaj tawm 73℃vim hais tias nws yog sandwiched ntawm ob lwm ZR modules nrog airflow tsis txaus. Qhov txuas tau ua haujlwm-nqhis- nrog kev kho FEC siab uas tsis muaj leej twg pom txog thaum ua ntej -FEC BER tau dhau los ntawm qhov pib thiab pob ntawv pib poob.

ZR + thiab MZR variants thawb mus txog ntxiv ntawm tus nqi ntawm kev sib cuam tshuam. Tus neeg muag khoom-Kev txhim kho tshwj xeeb rau kev tso tawm hluav taws xob, kev nkag siab ntawm tus neeg txais, thiab FEC algorithms tuaj yeem txuas txuas mus dhau 400km, tab sis koj tab tom yuav ib qho kev daws teeb meem ntau dua li cov khoom lag luam.

 

 

Thib peb-Cov Lus Nug

 

Kuv twb muaj qhov kev sib tham no kwv yees li rau pua zaus.

"Peb puas tuaj yeem siv thib peb- tog 400G optics?"

Technically yog. MSA cov kev qhia tshwj xeeb muaj nyob ua ke los ua kom muaj ntau yam - neeg muag khoom sib cuam tshuam. Raws li QSFP-DD los ntawm cov chaw tsim khoom X yuav tsum coj tus cwj pwm zoo ib yam los ntawm cov chaw tsim khoom Y. Cov qauv IEEE txhais cov kev ntsuas qhov muag thiab hluav taws xob. CMIS (Common Management Interface Specification) ua qauv li cas tus tswv tsev hais lus rau lub module.

Tswv yim, nws nyob ntawm.

Cisco's authentication mechanisms tau hloov zuj zus los ntawm blunt "yuam kev-lov tes taw qhov chaw nres nkoj" mus kom ze ntawm cov laus platforms mus rau ntau sophisticated neeg muag khoom pov thawj uas teev cov lus ceeb toom tab sis tsis tas yuav lov tes taw functionality. Cov kev pabcuam tsis tau txais kev txhawb nqa -transceiver cov lus txib tseem yog qhov khiav tawm. Arista nyiam ntau tso cai tab sis yuav tsis kam txhawb cov teeb meem uas yuav tshwm sim los ntawm thib peb -party modules. Juniper lub stance txawv ntawm platform thiab software version nyob rau hauv txoj kev uas yuav tsum tau sab laj nrog lawv compatibility matrices.

Kuv khiav qhov thib peb - tog optics nyob rau hauv ib puag ncig lab yam tsis muaj hesitation. Rau kev tsim khoom nqa cov nyiaj tau los ntawm 2 AM thaum ib yam dab tsi ua tsis tiav? Kuv xav tuaj yeem hu rau TAC thiab kom lawv pab tau es tsis txhob tam sim ntawd deflecting "hloov nrog cov transceivers txhawb."

Tus nqi lej hloov qhov kev suav no rau hyperscalers uas yuav cov qauv los ntawm kaum tawm txhiab tus thiab ntiav cov kws kho qhov muag uas tuaj yeem ua tus yam ntxwv thiab tsim nyog rau cov neeg muag khoom ntawm nws tus kheej. Nws yog lej sib txawv rau cov lag luam yuav ntau pua ntawm cov modules los ntawm kev faib tawm nrog cov peev txheej kev siv tsawg.

 

Thermal Reality

 

400G QSFP-DD module kos qhov chaw ntawm 10 thiab 15 watts nyob ntawm qhov sib txawv thiab tus neeg muag khoom. Lub 400G coherent ZR module kos 15-20 watts. Ib qho 800G QSFP{11}}DD800 module- twb tau muab tso rau hauv AI pawg-daws 18-25 watts.

Muab 64 ntawm cov no rau hauv 2RU hloov thiab koj muaj 640 watts tsuas yog los ntawm optics ua ntej suav rau kev hloov ASIC, nco, kiv cua, thiab cov khoom siv fais fab. Qhov teeb meem tsim thermal tau hloov ntawm "tsim" mus rau "tseem ceeb" hauv ib tiam.

Kuv saib lub koob yees duab thermal cheb lub siab -loaded 400G txha nraub qaum hloov thaum lub sij hawm xeem ntawv. Qhov kub tshaj plaws modules tsis yog qhov koj xav tau. Lub kaum sab xis txoj haujlwm, nqes nqes ntawm ASIC tso pa tawm, khiav kub dua lub ntsej muag- phaj nruab nrab modules uas tau txais huab cua ntshiab. Tus qauv DDM kub nyeem tau pom 17℃kis thoob plaws cov chaw nres nkoj uas xav tias zoo ib yam.

Cov qauv qhia tshwj xeeb cog lus ua haujlwm ntawm 0℃txog 70 degree, tab sis qhov kev ua haujlwm nkhaus tsis zoo ib yam ntawm 70℃raws li lawv ua ntawm 25 degree. Laser qhov pib tam sim no nce. Slope efficiency txo. Wavelength drifts-thiab rau CWDM4 thiab DWDM systems, wavelength drift txhais tau hais tias crosstalk nrog cov channel uas nyob ib sab.

Cua-cov tshuab cua txias tau nce mus txog qhov txwv. Cov kua cua txias rau cov keyboards tseem txawv tab sis nce ntxiv rau AI / ML pawg qhov twg GPUs thiab optics sib tw rau tib lub peev nyiaj thermal.

 

 

Kev Xeem Tseeb

 

Cov qauv IEEE txhais cov ntsiab lus ua raws cai. Lawv tsis lav tias koj qhov txuas tshwj xeeb yuav ua haujlwm.

TDECQ (Transmitter and Dispersion Eye Closure Quaternary) yog PAM4 sib npaug ntawm OMA (Optical Modulation Amplitude) tab sis nyuaj dua. Nws sim ua tus yam ntxwv zoo ntawm lub tshuab xa hluav taws xob hauv txoj hauv kev uas kwv yees cov neeg txais kev ua tau zoo. Kev ntsuas yuav tsum tau txais cov neeg siv khoom siv thiab cov lej hloov pauv uas sib txawv ntawm cov neeg muag khoom siv sim hauv txoj hauv kev uas ua rau muaj kev sib cav tsis sib haum ntawm pawg tswj hwm.

Ua ntej-Kev xeem FEC BER tseem ceeb tshaj qhov nws tau ua. Qhov "tus ntiv tes" ntawm koj qhov yuam kev me ntsis-random piv rau bursty, sib npaug sib piv piv rau cov ntsiab lus hauv cov cim PAM4 tshwj xeeb- txiav txim siab seb koj FEC puas tuaj yeem kho lawv. Qhov tseeb random yuam kev ua si zoo nrog Reed -Solomon codes. Kev tawg ua yuam kev los ntawm cov teeb meem rov qab moos lossis DSP tus cwj pwm tsis zoo tuaj yeem cuam tshuam FEC txawm tias BER nyoos zoo li tau txais.

Kuv tau kawm kom thov ua ntej -FEC cov txheeb cais los ntawm txhua qhov txuas 400G, tsis yog tshaj tawm -FEC. Ib qhov txuas uas qhia 0.00 tshaj tawm-FEC BER thaum khiav ua ntej-FEC BER ntawm 2 × 10⁻⁴ zoo heev kom txog rau thaum koj paub tias yuav luag tsis muaj qhov seem seem. Ntxiv ib qho kev sib txuas me ntsis qias neeg lossis ib qho kev laus laser, thiab qhov txuas ntawd yuav tawm ntawm FEC pob tsuas yam tsis tau ceeb toom.

 

Connector Contamination

 

Ntawm 400G qhov teeb meem kis kab mob ua rau mob hnyav. Lub qhov muag modulated muaj tsawg dua. Cov khoom uas yuav tsis pom ntawm qhov qis qis tam sim no attenuate txaus los teeb meem.

Tib - hom fiber ntau cores yog 9 micrometers thoob plaws. Ib qho MTP/MPO-12 connector nqa yim txoj kev siv fiber ntau (plaub TX, plaub RX) ntxiv rau plaub yam tsis siv. Txhua lub voj voog mating muaj kev pheej hmoo kis kab mob. Txhua lub ntsej muag uas muaj kab mob ua rau muaj kev pheej hmoo ntawm kev poob uas noj rau hauv koj cov peev nyiaj txuas.

Kev qhuab ntuas tu yuav tsum tsis yog- sib tham tau tab sis tsis tshua ua raws li qhov tsis tu ncua. Ib qho -nias cov tshuaj ntxuav tes, cov ntaub so qhuav qhuav nrog kev txhawj xeeb zoo li qub, ntxuav ntub dej nrog isopropyl cawv uas yuav tsum tau muab so kom qhuav tam sim ntawd es tsis tso cai rau evaporate -txhua txoj hauv kev muaj cov neeg koom nrog thiab cov neeg thuam. Txhua leej txhua tus pom zoo rau: tshuaj xyuas nrog lub fiber ntau ua ntej txuas, thiab yog tias nws qias neeg, ntxuav nws thiab tshuaj xyuas dua.

Kuv saib ib pab neeg xa mus hlawv tag nrho yav tav su daws teeb meem ib ntus 400G-DR4 txuas. Module sib pauv. Configuration tshuaj xyuas. Thaum kawg tau tawg tawm qhov kev tshuaj ntsuam xyuas thiab pom cov khoom siv khib nyiab ntawm lub bulkhead adapter uas tsis muaj leej twg xav kuaj. Nees nkaum vib nas this nrog lub cuab yeej tu kho qhov plaub teev ntawm kev daws teeb meem tsis tuaj yeem.

 

 

Qhov no txhais tau li cas rau Kev Npaj

 

Yog tias koj tab tom siv cov ntaub ntawv tshiab niaj hnub no, 400G yog lub hauv paus rau txheej txheej txha nraub qaum thiab nce ntxiv rau nplooj - txha nraub qaum. Tus nqi ib me ntsis tau nqis mus rau qhov twg 4 × 100G breakout los ntawm 400G modules feem ntau pheej yig dua tus neeg 100G modules. DR4 rau txhua yam tshaj 30 meters hauv ib lub tsev. FR4 rau tsev kawm ntawv interconnects. LR4 lossis ZR yog tias koj mus txog ntawm qhov chaw.

Yog tias koj yog ib lub lag luam xav txog koj thawj 400G kev xa tawm, cov kev hloov pauv hloov pauv tau loj tuaj, cov khoom lag luam module tau ruaj khov, thiab tus nqi tsis tas yuav tsum tau kos npe rau thawj tswj hwm - tawm ntawm txhua daim ntawv xaj yuav khoom. Pib nrog nplooj - txha nraub qaum rov ua dua tshiab, ua pov thawj tias koj cov kab ke txuas txuas tuaj yeem ua rau kev tiv thaiv kev sib kis nruj dua, thiab nkag siab tias koj cov cuab yeej tswj hwm yuav tsum tau pib sau cov ntaub ntawv FEC ua ntej koj xav tau.

Yog tias koj yog hyperscaler nyeem qhov no, koj twb dhau los 400G rau GPU pawg thiab xav paub seb 1.6T yuav siv tau li cas. Hmoov zoo nrog cov teeb meem thermal; Kuv mam li nyeem koj cov ntawv hauv ob xyoos.

Cov modules lawv tus kheej tau dhau los ua kev ntseeg tau zoo heev. Cov teeb meem nyob txhua qhov chaw: cov khoom sib kis tsis zoo, cov qauv FEC tsis raug, cov qauv tsim hluav taws xob uas xav tias nag hmo lub hnab ntawv fais fab, thiab cov koom haum txhawb nqa tseem kawm paub daws teeb meem PAM4 teeb meem kev ncaj ncees li cas. Cov ntsiab lus tsis txaus ntseeg - ntxuav koj cov khoom sib txuas, ntsuas koj qhov kub thiab txias, nkag siab txog koj cov peev nyiaj FEC- tseem ceeb ntau dua li cov lus qhia tshwj xeeb uas yuav muaj.