1 Isingeniso
I-PoE ibizwa nangokuthi i-Power over LAN (PoL) noma i-Active Ethernet, ngezinye izikhathi ebizwa ngokuthi Amandla phezu kwe-Ethernet ngamafuphi.Lokhu ukucaciswa okujwayelekile kwakamuva okusebenzisa izintambo zokudlulisa ezijwayelekile ze-Ethernet ukuze kudluliselwe idatha namandla ngesikhathi esifanayo, futhi kugcine ukuhambisana nezinhlelo ezikhona ze-Ethernet nabasebenzisi.Izinga le-IEEE 802.3af liyindinganiso entsha esekelwe ku-POE yohlelo lwe-Power-over-Ethernet.Yengeza amazinga ahlobene okunikezwa kwamandla okuqondile ngamakhebuli enethiwekhi ngesisekelo se-IEEE 802.3.Kuyisandiso sezinga elikhona le-Ethernet kanye nezinga lokuqala lamazwe ngamazwe lokusabalalisa amandla.ejwayelekile.
I-IEEE yaqala ukuthuthukisa izinga ngo-1999, futhi abathengisi bokuqala ababebambe iqhaza kwakuyi-3Com, Intel, PowerDsine, Nortel, Mitel, kanye ne-National Semiconductor.Kodwa-ke, ukuntuleka kwaleli zinga bekukhawulela ukwanda kwemakethe.Kuze kube nguJuni 2003, i-IEEE igunyaze izinga le-802.3af, elicacise ngokusobala ukutholwa kwamandla nokulawula izinto kumasistimu akude, namarutha axhunyiwe, amaswishi, namahabhu kumafoni we-IP, amasistimu okuvikela, namanethiwekhi endawo angenantambo ngamakhebula e-Ethernet.Indlela yokunikeza amandla amaphuzu nezinye izinto zokusebenza ilawulwa.Ukuthuthukiswa kwe-IEEE 802.3af kufaka phakathi imizamo yochwepheshe abaningi benkampani, okuvumela futhi izinga ukuthi lihlolwe ngokugcwele.
Amandla ajwayelekile phezu kwesistimu ye-Ethernet.Faka okokusebenza kokushintsha kwe-Ethernet ekhabetheni lezintambo, bese usebenzisa ihabhu elimaphakathi ne-span elinehabhu yamandla ukuze unikeze amandla kupheya esontekile ye-LAN.Ekupheleni kokupheya okusontekile, ukunikezwa kwamandla kusetshenziselwa ukunika amandla amafoni, izindawo zokufinyelela ezingenantambo, amakhamera, namanye amadivayisi.Ukuze ugweme ukuphela kukagesi, i-UPS ingasetshenziswa.
2 isimiso
Ikhebuli yenethiwekhi yeSigaba 5 esijwayelekile inamapheya amane wamapheya asontiwe, kodwa amabili kuphela awo asetshenziswa ku-l0M BASE-T naku-100M BASE-T.IEEE80 2.3af ivumela ukusetshenziswa okubili.Uma iphinikhodi yokungenzi lutho isetshenziselwa ukunikezwa kwamandla, izikhonkwane 4 no-5 zixhunywe njengesigxobo esiqondile, futhi izikhonkwane 7 no-8 zixhunywe njengesigxobo esinegethivu.
Lapho iphinikhodi yedatha isetshenziselwa ukunikezwa kwamandla, amandla kagesi e-DC afakwa phakathi nendawo ye-transformer yokudlulisa, engathinti ukudluliswa kwedatha.Ngale ndlela, i-pair 1, 2 kanye ne-3, 6 ingaba nanoma iyiphi i-polarity.
Izinga alikuvumeli ukusetshenziswa kwezimo ezimbili ezingenhla ngesikhathi esisodwa.I-PSE yemishini yokunikeza amandla inganikeza ukusetshenziswa okukodwa kuphela, kodwa i-PD yemishini yohlelo lokusebenza kufanele ikwazi ukuzivumelanisa nezimo zombili ngesikhathi esisodwa.Izinga libeka ukuthi ukunikezwa kwamandla kuvamise ukuba ngu-48V, 13W.Kulula kumishini ye-PD ukunikeza i-48V ukuguqulwa kwamandla kagesi aphansi, kodwa ngesikhathi esifanayo kufanele ibe ne-voltage yokuphepha yokuhlukanisa engu-1500V.
3 amapharamitha
Uhlelo oluphelele lwe-POE luhlanganisa izingxenye ezimbili: okokusebenza kwamandla kagesi (PSE) kanye nemishini yokuphakela amandla (PD).Idivayisi ye-PSE iyithuluzi elinikeza amandla kudivayisi yeklayenti le-Ethernet, futhi lingumphathi wayo yonke inqubo yokunikezwa kwamandla ye-POE Ethernet.Idivayisi ye-PD ingumthwalo we-PSE owamukela amandla, okungukuthi, idivayisi yeklayenti yohlelo lwe-POE, njengamafoni we-IP, amakhamera okuphepha enethiwekhi, ama-APs, namanye amadivaysi e-Ethernet amaningi, njengama-PDA noma amashaja eselula (empeleni, noma imaphi amandla aweqi ku-13W Idivayisi ingathola amandla ahambisanayo kusokhethi RJ45).Lokhu kokubili kusekelwe ezingeni le-IEEE 802.3af futhi kusungulwe uxhumano ngoxhumano lwe-PD, uhlobo lwedivayisi, izinga lokusetshenziswa kwamandla nolunye ulwazi lwedivayisi yokwamukela amandla, futhi ngalesi sisekelo, i-PD inikwa amandla yi-PSE nge-Ethernet.
Imingcele yesici sokuphakelwa kwamandla eyinhloko yesistimu yokuhlinzeka ngamandla kagesi ye-POE yilezi:
1. I-voltage iphakathi kuka-44V no-57V, enenani elijwayelekile elingu-48V.
2. Umkhawulo wamanje ovumelekile ngu-550mA, kanti umkhawulo wokuqala wamanje ngu-500mA.
3. Amandla okusebenza ajwayelekile ngu-10-350mA, kanti ukutholwa kokugcwala ngokweqile kungu-350-500mA.
4. Ngaphansi kwezimo zokungalayishi, ubukhulu obudingekayo bamanje ngu-5mA.
5. Nikeza amazinga amathathu wezidingo zamandla kagesi we-3.84～12.95W wempahla ye-PD, umkhawulo awudluli u-13W.(Qaphela ukuthi amazinga e-PD 0 kanye no-4 awabonisiwe futhi akufanele asetshenziswe.)
4 inqubo yokusebenza
Lapho uhlela okokusebenza kwetheminali ye-PSE kagesi kunethiwekhi, inqubo yokusebenza ye-POE Amandla phezu kwe-Ethernet iboniswa ngezansi.
1. Ukutholwa
Ekuqaleni, idivayisi ye-PSE ikhipha i-voltage encane kakhulu embobeni ize ithole ukuthi ukuxhumeka kwetheminali yekhebula kuyidivayisi yokwamukela amandla esekela izinga le-IEEE 802.3af.
2. Ukuhlukaniswa kwedivayisi ye-PD
Uma i-PD yedivayisi yokugcina eyamukelayo itholwa, idivayisi ye-PSE ingase ihlukanise idivayisi ye-PD futhi ihlole ukulahleka kwamandla okudingeka idivayisi ye-PD.
Phakathi nesikhathi sokuqalisa sesikhathi esilungisekayo (ngokuvamile esingaphansi kuka-15μs), idivayisi ye-PSE iqala ukunikeza amandla kudivayisi ye-PD isuka kuvolthi ephansi ize inikeze amandla kagesi angu-48V DC.
4. Ukunikezwa kwamandla
Ihlinzeka ngamandla aqinile nathembekile we-48V DC wemishini ye-PD ukuze ahlangabezane nokusetshenziswa kwamandla kwemishini ye-PD engeqi ku-15.4W.
5. Cisha amandla
Uma idivayisi ye-PD inqanyuliwe kunethiwekhi, i-PSE izoshesha (imvamisa phakathi kuka-300-400ms) iyeke ukunika amandla idivayisi ye-PD, futhi iphinda inqubo yokuthola ukuze ithole ukuthi ingabe itheminali yekhebula ixhunywe kudivayisi ye-PD.
5 indlela yokunikeza amandla
Izinga le-PoE lichaza izindlela ezimbili zokusebenzisa izintambo zokudlulisela ze-Ethernet ukudlulisa amandla e-DC kumadivayisi ahambisana ne-POE:
1.Mid-Span
Sebenzisa amapheya ezintambo ezingasebenzi angasetshenzisiwe kukhebula ye-Ethernet ukuze udlulise amandla e-DC.Isetshenziswa phakathi kokushintsha okujwayelekile kanye nemishini yokugcina inethiwekhi.Ingakwazi ukunikeza amandla kutheminali yenethiwekhi ngentambo yenethiwekhi.I-Midspan PSE (imishini yokuphakela amandla emaphakathi ne-span) iyisisetshenziswa esikhethekile sokuphatha amandla, ngokuvamile esihlanganiswa nesishintshi.Inamajekhi amabili e-RJ45 ahambisana nembobo ngayinye, eyodwa ixhunywe kusishintshi ngekhebula elifushane, kanti enye ixhunywe kusisetshenziswa esikude.
I-Span yokuphela
I-current eqondile idluliselwa kanyekanye ocingweni oluyinhloko olusetshenziselwa ukudluliswa kwedatha, futhi ukudluliselwa kwayo kusebenzisa imvamisa ehlukile kunesignali yedatha ye-Ethernet.I-Endpoint PSE ehambisanayo (imishini yokunikeza amandla esiphetho) ineswishi ye-Ethernet, irutha, ihabhu noma enye impahla yokushintsha inethiwekhi esekela umsebenzi we-POE.Kuyabonakala ukuthi i-End-Span izophromothwa ngokushesha.Lokhu kungenxa yokuthi idatha ye-Ethernet nokudluliswa kwamandla kusebenzisa ipheya evamile, eqeda isidingo sokusetha umugqa ozinikele wokudluliswa kwamandla okuzimele.Lokhu okwezintambo ezingu-8-core kuphela kanye ne-RJ ejwayelekile efanayo- Isokhethi engu-45 ibaluleke kakhulu.
6 intuthuko
I-PowerDsine, umkhiqizi we-chip we-power-over-Ethernet, izobamba umhlangano we-IEEE ukuze ithumele ngokusemthethweni izinga “lamandla aphezulu-amandla-phezu kwe-Ethernet”, elizosekela ukuphakelwa kwamandla kumalaptop namanye amadivayisi.I-PowerDsine izohambisa iphepha elimhlophe, eliphakamisa ukuthi okokufaka okujwayelekile okungu-802.3af 48v kanye nomkhawulo wamandla otholakalayo ongu-13w kufanele uphindwe kabili.Ngokungeziwe kumakhompiyutha wezincwadi, izinga elisha lingaphinda libe namandla ezibukweni zekristalu ewuketshezi namafoni evidiyo.Ngomhla zingama-30 kuMfumfu, 2009, i-IEEE yakhipha izinga elisha kakhulu le-802.3at, elibeka ukuthi i-POE inganikeza amandla aphakeme, angaphezu kuka-13W futhi angafinyelela ku-30W!