I-IPv4 iyinguqulo yesine ye-Internet Protocol (IP) kanye nephrothokholi yokuqala esetshenziswa kabanzi eyenza isisekelo sobuchwepheshe be-inthanethi banamuhla. Idivayisi ngayinye nesizinda esixhunywe ku-inthanethi sinikezwe inombolo ehlukile ebizwa ngekheli le-IP. Ikheli le-IPv4 inombolo engu-32-bit eyakhiwe amadesimali amane. Phakathi kwesihlukanisi sedesimali ngayinye kunenombolo ephakathi kuka-0 no-255. Isibonelo: 192.0.2.235
Namuhla, ngenxa yemvelo entsha ye-IPv6, i-IPv4 iseyisisekelo semisebenzi eminingi ye-inthanethi, futhi amadivayisi amaningi acushwa nge-IPv4. Kulesi simo, amadivayisi amaningi awakwazi ukuxhumana kusetshenziswa i-IPv6, okuholela kubantu abaningi, amabhizinisi, nabanye abasadinga i-IPv4. Okulandelayo, sizokwethula ifomethi yephakethe ye-IPv4.
Ifomethi yephakethe le-IPv4
(1)Inguquloi-akhawunti yenkundla yamabhithi angu-4, okubonisa inguqulo yephrothokholi ye-IP.
(2)Ubude Besihloko se-IP, le nkambu isetshenziselwa ukuchaza ubude besihloko se-IP, njengoba kunezingxenye ozikhethela zobude obuguquguqukayo kunhlokweni ye-IP. Lesi sigaba sithatha amabhithi angu-4, aneyunithi yobude engamabhayithi angu-4, okusho ukuthi inani kulesi sifunda=ubude besihloko se-IP (ngamabhayithi)/iyunithi yobude (amabhayithi angu-4).
(3)Uhlobo Lwesevisi: amabhithi angu-8 ubude.
I-PPP: Amadijithi amathathu okuqala achaza ukubaluleka kwephakheji. Uma inani libaluleke kakhulu, kubaluleke kakhulu ukuthi idatha Enkulu ibaluleke kakhulu
000 (Umjikelezo) Ojwayelekile
001 (Okubalulekile) okubalulekile, okusetshenziselwa ibhizinisi ledatha
010 (Ngokushesha) ngokushesha, yebhizinisi ledatha
011 (Flash) isivinini sokudlulisa izwi
100 (Ukukhishwa kwe-Flash) ngokushesha kwebhizinisi levidiyo
I-101 (ebucayi) i-CRI/TIC/ECP ebalulekile ekudlulisweni kwezwi
110 (Ukulawulwa Kwe-inthanethi) Ukulawulwa kwenethiwekhi ye-Inter, okusetshenziselwa ukulawula inethiwekhi, njengezivumelwano zomzila
111 (Network Control) isilawuli senethiwekhi, esisetshenziselwa ukulawula inethiwekhi
I-DTRCO: Izinombolo zokugcina ezi-5
(1000) D ukubambezeleka: 0: ukulibaziseka kwamaminithi, 1: nciphisa ukubambezeleka ngangokunokwenzeka
(0100) T throughput: 0: max throughput (ubuningi bokuphuma), 1: Zama ukukhulisa ithrafikhi ngangokunokwenzeka
(0010) ukwethembeka kuka-R: 0: umkhawulo wokusebenza, 1: khulisa ukwethembeka
(0001) M Izindleko zokudlulisela: 0: iminithi izindleko zangoMsombuluko (ubuncane bendlela ephezulu), 1: nciphisa izindleko ngendlela ongakhona ngayo
(0000): evamile (isevisi evamile).
(4)Ubude obuphelele bephakethe le-IP: amabhithi angu-16 ubude. Ubude bephakethe le-IP elibalwa ngamabhayithi (okuhlanganisa unhlokweni nedatha), ngakho-ke ubude obukhulu bephakethe le-IP bungamabhayithi angu-65 535. Ngakho, usayizi wephakethe payload=Isamba sobude bephakethe le-IP - ubude besihloko se-IP.
(5)Isihlonzi: amabhithi angu-16 ubude. Le nkambu isetshenziswa ngokuhambisana nezinkambu zefulegi kanye ne-Fragment Offer ukuze kuhlukaniswe amaphakethe aphezulu aphezulu. Ngemva kweumzilaihlukanisa iphakethe, wonke amaphakethe amancane ahlukanisiwe amakwe ngenani elifanayo, ukuze idivayisi yendawo ikwazi ukuhlukanisa ukuthi yiliphi iphakethe elingelephakethe elihlukanisayo.
(6)Amafulegi: amabhithi angu-3 ubude.
Idijithi yokuqala yale nkambu ayisetshenziswa.
Ibhithi yesibili yi-DF (Don't Fragment) bit. Uma ibhithi ye-DF isethelwe ku-1, ikhombisa ukuthi i-umzilaayikwazi ukuhlukanisa iphakethe lesendlalelo esingaphezulu. Uma iphakethe lesendlalelo esiphezulu lingakwazi ukuthunyelwa ngaphandle kokuhlukaniswa, iumzilaizolahla iphakethe lesendlalelo esiphezulu bese ibuyisela umlayezo wephutha.
Ibhithi yesithathu yi-MF (More Fragments) bit. Lapho i-umzilaihlukanisa iphakethe lesendlalelo esiphezulu, isetha ibhithi ye-MF ibe ngu-1 kunhlokweni yephakethe le-IP ngaphandle kwengxenye yokugcina.
(7)I-Fragment Offset: Ubude bamabhithi angu-13, kukalwa ngamayunithi angu-8 octet. Ibonisa indawo yephakethe le-IP kuphakethe lengxenye, esetshenziswa ekugcineni kokwamukela ukuhlanganisa nokubuyisela iphakethe le-IP.
(8)Isikhathi Sokuphila (TTL): Ubude bungamabhithi angu-8, aklanywe ekuqaleni ngamasekhondi (amasekhondi), kodwa empeleni akalwa ngama-hops. Inani elimisiwe elinconywayo lingu-64. Uma amaphakethe e-IP asakazwa, inani elithile linikezwa kuqala kule nkambu. Lapho iphakethe le-IP lidlula ngakunyeumzilaendleleni, ngamunyeumzilaendleleni izonciphisa inani le-TTL lephakethe le-IP ngo-1. Uma i-TTL yehliswa ibe ngu-0, iphakethe le-IP lizolahlwa. Le nkambu ingavimbela amaphakethe e-IP ukuthi angadluliswa ngokuqhubekayo kunethiwekhi ngenxa yamaluphu omzila.
(9)Iphrothokholi: amabhithi angu-16 ubude. Isetshenziselwa ukutholwa kokulunga kwezihloko ze-IP, kodwa ayifaki isigaba sedatha. Ngoba ngamunyeumzilaidinga ukushintsha inani le-TTL, iumzilaizobala kabusha leli nani ngephakethe ngalinye elidlulayo
(10)I-Header Checksum: amabhithi angu-16 ubude. Isetshenziselwa ukutholwa kokulunga kwezihloko ze-IP, kodwa ayifaki isigaba sedatha. Ngoba ngamunyeumzilaidinga ukushintsha inani le-TTL, iumzilaizobala kabusha leli nani ngephakethe ngalinye elidlulayo
(11)Umthombo kanye namakheli endawo: Womabili amakheli angamabhithi angama-32. Ihlonza umsuka nekheli okuyiwa kulo laleli phakethe le-IP. Sicela uqaphele ukuthi ngaphandle kokuthi kusetshenziswe i-NAT, lawa makheli amabili ngeke ashintshe kuyo yonke inqubo yokudlulisela.
(12)Izinketho: Lena inkambu yobude obuguquguqukayo. Le nkambu ingokuzithandela futhi isetshenziselwa ukuhlola, futhi ingabhalwa kabusha idivayisi yokuqala njengoba kudingeka. Izinto ozikhethela zona zihlanganisa okulandelayo:
•Umzila womthombo oxekethile: Nikeza uchungechunge lwamakheli e-IP weumzilaizindawo zokuhlangana. Amaphakethe e-IP kufanele adluliselwe kulawa makheli e-IP, kodwa avunyelwe ukweqa amarutha amaningi phakathi kwamakheli e-IP amabili alandelanayo.
•Umzila womthombo oqinile: Nikeza uchungechunge lwamakheli e-IP weumzilaizindawo zokuhlangana. Amaphakethe e-IP kufanele adluliselwe kanye nalawa makheli e-IP, futhi uma i-hop elandelayo ingekho kuthebula lekheli le-IP, ikhombisa iphutha.
•Rekhoda umzila: Rekhoda ikheli le-IP lesixhumi esibonakalayo esiphumayo somzila lapho iphakethe le-IP lishiya ngalinyeumzila.
•Izitembu zesikhathi: Rekhoda isikhathi lapho iphakethe le-IP lishiya ngalinyeumzila.
•Ukupheda: Ngenxa yokuthi iyunithi yobude besihloko se-IP ingamabhithi angu-32, ubude besihloko se-IP kumelwe bube ukuphindaphinda okuphelele kwamabhithi angu-32. Ngakho-ke, ngemva kwenketho yokuzikhethela, iphrothokholi ye-IP izogcwalisa oziro abambalwa ukuze kuzuzwe inombolo ephelele yamabhithi angu-32.
Idatha ye-IPV4 ivame ukusetshenziswa kweyenkampani yethuI-ONUamadivayisi enethiwekhi, kanye nenethiwekhi yethu ehlobene nemikhiqizo edayiswayo eshisayo ihlanganisa izinhlobo ezahlukene zeI-ONUimikhiqizo yochungechunge, kuhlanganise ne-ACI-ONU/ukuxhumanaI-ONU/ehlakaniphileI-ONU/ibhokisiI-ONU, njll. OkungenhlaI-ONUimikhiqizo yochungechunge ingasetshenziselwa izidingo zenethiwekhi ezimeni ezahlukahlukene. Yamukela wonke umuntu ukuthi eze futhi abe nolwazi oluningiliziwe lobuchwepheshe lomkhiqizo.