Ikheli le-Media Access Control (MAC) liyinombolo kanambambili esetshenziselwa ukukhomba ngokukhethekile amakheli e-computer yenethiwekhi . Lezi zinombolo (ngezinye izikhathi ezibizwa ngokuthi "amakheli wehadiwe" noma "amakheli angokwenyama") zifakwe kwi-hardware yenethiwekhi phakathi nenqubo yokukhiqiza, noma zigcinwe ku-firmware, futhi zenzelwe ukuthi zingaguquki.
Abanye futhi babhekisela kubo ngokuthi "amakheli e-Ethernet" ngezizathu zomlando, kodwa izinhlobo eziningi zamanethiwekhi wonke zisebenzisa ikheli le-MAC kuhlanganise ne- Ethernet , i- Wi-Fi , ne- Bluetooth .
Ifomethi yekheli le-MAC
Amakheli wendabuko we-MAC amadijithi angu-12 (6 bytes noma ama-48 bits ) izinombolo ze-hexadecimal . Ngomhlangano, ngokuvamile kubhalwa kwelinye lamafomethi amathathu alandelayo:
- I-MM: MM: MM: SS: SS: SS
- I-MM-MM-MM-SS-SS-SS
- I-MMM.MMM.SSS.SSS
Amadijithi angu-6 angakwesokunxele (ama-24 bits) okuthiwa "isiqalo" ahlotshaniswa nomkhiqizi we-adapter. Umthengisi ngamunye ubhalisa futhi uthole ama-prefixes e-MAC njengoba anikezwe i-IEEE. Abathengisi bavame ukuba nezinombolo eziningi zesiqalo ezihlobene nemikhiqizo yazo ehlukene. Isibonelo, i-prefixes 00:13:10, 00: 25: 9C no-68: 7F: 74 (kanye nabanye abaningi) bonke bangabakwa-Linksys ( Cisco Systems ).
Idijithali elifanele kakhulu lekheli le-MAC limelela inombolo yokuhlonza yedivaysi ethile. Phakathi kwazo zonke amadivaysi akhiqizwa nesibalo esilinganayo somthengisi, ngamunye unikezwa inombolo yakhe eyingqayizivele engu-24-bit. Qaphela ukuthi i-hardware evela kubathengisi abahlukene kungenzeka kwenzeke ukwabelana ngengxenye efanayo yedivayisi yekheli.
Amakheli we-64-bit MAC
Ngenkathi amakheli wendabuko e-MAC enama-bits angu-48 ubude, izinhlobo ezimbalwa zamanethiwekhi zidinga amakheli angu-64-bit esikhundleni. I-ZigBee engenazintambo zangasese ezingenantambo namanye amanethiwekhi afanayo asekelwe ku-IEEE 802.15.4, isibonelo, zidinga amakheli angu-64-bit MAC alungiselelwe kumadivayisi wabo wehadiwe.
Amanethiwekhi we-TCP / IP asekelwe ku-IPv6 nawo asebenzisa indlela ehlukile yokuxhumana amakheli we-MAC uma kuqhathaniswa ne- IPv4 ejwayelekile . Esikhundleni samakheli we-64-bit hardware, noma kunjalo, i-IPv6 ihumusha ngokuzenzakalelayo ikheli le-48-bit MAC ekhelini le-64-bit ngokufaka i-value ye-FFFE engaguquki (enganaki) 16-bit phakathi kwesiqephu somthengisi kanye nesichazi sedivayisi. I-IPv6 ibiza lezi zinombolo "izikhombi" ukuze zihlukanise namakheli weqiniso we-64-bit hardware.
Isibonelo, ikheli le-MAC lama-48-bit 00: 25: 96: 12: 34: 56 livela kunethiwekhi ye- IPv6 njenge (ejwayelekile ebhalwe kulezi zindlela ezimbili):
- 00: 25: 96: FF: FE: 12: 34: 56
- 0025: 96FF: FE12: 3456
I-MAC ne-IP Address Relationship
Amanethiwekhi we- TCP / IP asebenzisa amakheli we-MAC namakheli e- IP kodwa ngezinhloso ezihlukile. Ikheli le-MAC lihlala lihleliwe kwi-hardware yedivaysi ngenkathi ikheli le-IP lensiza efanayo lingashintshwa kuye ngokucushwa kwesevisi ye-TCP / IP. Ukulawulwa Kwemidiya Yezokuxhumana kusebenza ku-Layer 2 ye- OSI model ngenkathi i- Inthanethi Protocol isebenza ku- Layer 3 . Lokhu kuvumela i-MAC ukubhekana nokusekela ezinye izinhlobo zamanethiwekhi ngaphandle kwe-TCP / IP.
Amanethiwekhi we-IP aphatha ukuguqulwa phakathi kwekheli le-IP ne- MAC esebenzisa i- Address Resolution Protocol (ARP) . I- Dynamic Host Configuration Protocol (DHCP) incike ku-ARP ukuphatha isabelo esiyingqayizivele samakheli e- IP kumadivayisi.
Ikheli le-MAC Cloning
Abanye Abanikezeli Bezinsizakalo ze-Intanethi baxhumanisa ama-akhawunti abo amakhasimende abo okuhlala kuwo amakheli e-MAC we- router network router (noma enye idivayisi yesango). Ikheli elibonwe ngumhlinzeki alishintshi kuze kube yilapho ikhasimende lifaka indawo yesango, njengokufaka i- router entsha . Lapho isango lokuhlala liguqulwa, umhlinzeki we-Inthanethi manje ubona ikheli le-MAC elihlukile elibikwayo futhi livimbela leyo nethiwekhi ukuba ingene ku-intanethi.
Inqubo ebizwa ngokuthi "cloning" ixazulula le nkinga ngokuvumela i-router (isango) ukuthi liqhubeke libika ikheli elidala le-MAC kumhlinzeki ngisho noma ikheli layo lehadiwe lihlukile. Abaphathi bangakwazi ukulungisa router yabo (becabanga ukuthi isekela lesi sici, njengoba abaningi benza) ukusebenzisa ukhetho cloning bese ufaka ikheli le-MAC yesango elidala ekrinini ukumisa. Uma i-cloning ingatholakali, ikhasimende kufanele lithintane nomhlinzeki wesevisi ukuze babhalise idivayisi entsha yesango kunalokho.